Adding upstream version 6.1.76.upstream/6.1.76upstream

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

36 files changed, 16464 insertions, 0 deletions

diff --git a/fs/proc/Kconfig b/fs/proc/Kconfig
new file mode 100644
index 000000000..32b1116ae
--- /dev/null
+++ b/fs/proc/Kconfig
@@ -0,0 +1,110 @@
+# SPDX-License-Identifier: GPL-2.0-only
+config PROC_FS
+	bool "/proc file system support" if EXPERT
+	default y
+	help
+	  This is a virtual file system providing information about the status
+	  of the system. "Virtual" means that it doesn't take up any space on
+	  your hard disk: the files are created on the fly by the kernel when
+	  you try to access them. Also, you cannot read the files with older
+	  version of the program less: you need to use more or cat.
+
+	  It's totally cool; for example, "cat /proc/interrupts" gives
+	  information about what the different IRQs are used for at the moment
+	  (there is a small number of Interrupt ReQuest lines in your computer
+	  that are used by the attached devices to gain the CPU's attention --
+	  often a source of trouble if two devices are mistakenly configured
+	  to use the same IRQ). The program procinfo to display some
+	  information about your system gathered from the /proc file system.
+
+	  Before you can use the /proc file system, it has to be mounted,
+	  meaning it has to be given a location in the directory hierarchy.
+	  That location should be /proc. A command such as "mount -t proc proc
+	  /proc" or the equivalent line in /etc/fstab does the job.
+
+	  The /proc file system is explained in the file
+	  <file:Documentation/filesystems/proc.rst> and on the proc(5) manpage
+	  ("man 5 proc").
+
+	  This option will enlarge your kernel by about 67 KB. Several
+	  programs depend on this, so everyone should say Y here.
+
+config PROC_KCORE
+	bool "/proc/kcore support" if !ARM
+	depends on PROC_FS && MMU
+	select CRASH_CORE
+	help
+	  Provides a virtual ELF core file of the live kernel.  This can
+	  be read with gdb and other ELF tools.  No modifications can be
+	  made using this mechanism.
+
+config PROC_VMCORE
+	bool "/proc/vmcore support"
+	depends on PROC_FS && CRASH_DUMP
+	default y
+	help
+	  Exports the dump image of crashed kernel in ELF format.
+
+config PROC_VMCORE_DEVICE_DUMP
+	bool "Device Hardware/Firmware Log Collection"
+	depends on PROC_VMCORE
+	default n
+	help
+	  After kernel panic, device drivers can collect the device
+	  specific snapshot of their hardware or firmware before the
+	  underlying devices are initialized in crash recovery kernel.
+	  Note that the device driver must be present in the crash
+	  recovery kernel's initramfs to collect its underlying device
+	  snapshot.
+
+	  If you say Y here, the collected device dumps will be added
+	  as ELF notes to /proc/vmcore. You can still disable device
+	  dump using the kernel command line option 'novmcoredd'.
+
+config PROC_SYSCTL
+	bool "Sysctl support (/proc/sys)" if EXPERT
+	depends on PROC_FS
+	select SYSCTL
+	default y
+	help
+	  The sysctl interface provides a means of dynamically changing
+	  certain kernel parameters and variables on the fly without requiring
+	  a recompile of the kernel or reboot of the system.  The primary
+	  interface is through /proc/sys.  If you say Y here a tree of
+	  modifiable sysctl entries will be generated beneath the
+	  /proc/sys directory. They are explained in the files
+	  in <file:Documentation/admin-guide/sysctl/>.  Note that enabling this
+	  option will enlarge the kernel by at least 8 KB.
+
+	  As it is generally a good thing, you should say Y here unless
+	  building a kernel for install/rescue disks or your system is very
+	  limited in memory.
+
+config PROC_PAGE_MONITOR
+ 	default y
+	depends on PROC_FS && MMU
+	bool "Enable /proc page monitoring" if EXPERT
+ 	help
+	  Various /proc files exist to monitor process memory utilization:
+	  /proc/pid/smaps, /proc/pid/clear_refs, /proc/pid/pagemap,
+	  /proc/kpagecount, and /proc/kpageflags. Disabling these
+	  interfaces will reduce the size of the kernel by approximately 4kb.
+
+config PROC_CHILDREN
+	bool "Include /proc/<pid>/task/<tid>/children file"
+	depends on PROC_FS
+	default n
+	help
+	  Provides a fast way to retrieve first level children pids of a task. See
+	  <file:Documentation/filesystems/proc.rst> for more information.
+
+	  Say Y if you are running any user-space software which takes benefit from
+	  this interface. For example, rkt is such a piece of software.
+
+config PROC_PID_ARCH_STATUS
+	def_bool n
+	depends on PROC_FS
+
+config PROC_CPU_RESCTRL
+	def_bool n
+	depends on PROC_FS
diff --git a/fs/proc/Makefile b/fs/proc/Makefile
new file mode 100644
index 000000000..bd08616ed
--- /dev/null
+++ b/fs/proc/Makefile
@@ -0,0 +1,36 @@
+# SPDX-License-Identifier: GPL-2.0
+#
+# Makefile for the Linux proc filesystem routines.
+#
+
+obj-y   += proc.o
+
+CFLAGS_task_mmu.o	+= $(call cc-option,-Wno-override-init,)
+proc-y			:= nommu.o task_nommu.o
+proc-$(CONFIG_MMU)	:= task_mmu.o
+
+proc-y       += inode.o root.o base.o generic.o array.o \
+		fd.o
+proc-$(CONFIG_TTY)      += proc_tty.o
+proc-y	+= cmdline.o
+proc-y	+= consoles.o
+proc-y	+= cpuinfo.o
+proc-y	+= devices.o
+proc-y	+= interrupts.o
+proc-y	+= loadavg.o
+proc-y	+= meminfo.o
+proc-y	+= stat.o
+proc-y	+= uptime.o
+proc-y	+= util.o
+proc-y	+= version.o
+proc-y	+= softirqs.o
+proc-y	+= namespaces.o
+proc-y	+= self.o
+proc-y	+= thread_self.o
+proc-$(CONFIG_PROC_SYSCTL)	+= proc_sysctl.o
+proc-$(CONFIG_NET)		+= proc_net.o
+proc-$(CONFIG_PROC_KCORE)	+= kcore.o
+proc-$(CONFIG_PROC_VMCORE)	+= vmcore.o
+proc-$(CONFIG_PRINTK)	+= kmsg.o
+proc-$(CONFIG_PROC_PAGE_MONITOR)	+= page.o
+proc-$(CONFIG_BOOT_CONFIG)	+= bootconfig.o
diff --git a/fs/proc/array.c b/fs/proc/array.c
new file mode 100644
index 000000000..49283b810
--- /dev/null
+++ b/fs/proc/array.c
@@ -0,0 +1,803 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ *  linux/fs/proc/array.c
+ *
+ *  Copyright (C) 1992  by Linus Torvalds
+ *  based on ideas by Darren Senn
+ *
+ * Fixes:
+ * Michael. K. Johnson: stat,statm extensions.
+ *                      <johnsonm@stolaf.edu>
+ *
+ * Pauline Middelink :  Made cmdline,envline only break at '\0's, to
+ *                      make sure SET_PROCTITLE works. Also removed
+ *                      bad '!' which forced address recalculation for
+ *                      EVERY character on the current page.
+ *                      <middelin@polyware.iaf.nl>
+ *
+ * Danny ter Haar    :	added cpuinfo
+ *			<dth@cistron.nl>
+ *
+ * Alessandro Rubini :  profile extension.
+ *                      <rubini@ipvvis.unipv.it>
+ *
+ * Jeff Tranter      :  added BogoMips field to cpuinfo
+ *                      <Jeff_Tranter@Mitel.COM>
+ *
+ * Bruno Haible      :  remove 4K limit for the maps file
+ *			<haible@ma2s2.mathematik.uni-karlsruhe.de>
+ *
+ * Yves Arrouye      :  remove removal of trailing spaces in get_array.
+ *			<Yves.Arrouye@marin.fdn.fr>
+ *
+ * Jerome Forissier  :  added per-CPU time information to /proc/stat
+ *                      and /proc/<pid>/cpu extension
+ *                      <forissier@isia.cma.fr>
+ *			- Incorporation and non-SMP safe operation
+ *			of forissier patch in 2.1.78 by
+ *			Hans Marcus <crowbar@concepts.nl>
+ *
+ * aeb@cwi.nl        :  /proc/partitions
+ *
+ *
+ * Alan Cox	     :  security fixes.
+ *			<alan@lxorguk.ukuu.org.uk>
+ *
+ * Al Viro           :  safe handling of mm_struct
+ *
+ * Gerhard Wichert   :  added BIGMEM support
+ * Siemens AG           <Gerhard.Wichert@pdb.siemens.de>
+ *
+ * Al Viro & Jeff Garzik :  moved most of the thing into base.c and
+ *			 :  proc_misc.c. The rest may eventually go into
+ *			 :  base.c too.
+ */
+
+#include <linux/types.h>
+#include <linux/errno.h>
+#include <linux/time.h>
+#include <linux/time_namespace.h>
+#include <linux/kernel.h>
+#include <linux/kernel_stat.h>
+#include <linux/tty.h>
+#include <linux/string.h>
+#include <linux/mman.h>
+#include <linux/sched/mm.h>
+#include <linux/sched/numa_balancing.h>
+#include <linux/sched/task_stack.h>
+#include <linux/sched/task.h>
+#include <linux/sched/cputime.h>
+#include <linux/proc_fs.h>
+#include <linux/ioport.h>
+#include <linux/io.h>
+#include <linux/mm.h>
+#include <linux/hugetlb.h>
+#include <linux/pagemap.h>
+#include <linux/swap.h>
+#include <linux/smp.h>
+#include <linux/signal.h>
+#include <linux/highmem.h>
+#include <linux/file.h>
+#include <linux/fdtable.h>
+#include <linux/times.h>
+#include <linux/cpuset.h>
+#include <linux/rcupdate.h>
+#include <linux/delayacct.h>
+#include <linux/seq_file.h>
+#include <linux/pid_namespace.h>
+#include <linux/prctl.h>
+#include <linux/ptrace.h>
+#include <linux/string_helpers.h>
+#include <linux/user_namespace.h>
+#include <linux/fs_struct.h>
+#include <linux/kthread.h>
+
+#include <asm/processor.h>
+#include "internal.h"
+
+void proc_task_name(struct seq_file *m, struct task_struct *p, bool escape)
+{
+	char tcomm[64];
+
+	/*
+	 * Test before PF_KTHREAD because all workqueue worker threads are
+	 * kernel threads.
+	 */
+	if (p->flags & PF_WQ_WORKER)
+		wq_worker_comm(tcomm, sizeof(tcomm), p);
+	else if (p->flags & PF_KTHREAD)
+		get_kthread_comm(tcomm, sizeof(tcomm), p);
+	else
+		__get_task_comm(tcomm, sizeof(tcomm), p);
+
+	if (escape)
+		seq_escape_str(m, tcomm, ESCAPE_SPACE | ESCAPE_SPECIAL, "\n\\");
+	else
+		seq_printf(m, "%.64s", tcomm);
+}
+
+/*
+ * The task state array is a strange "bitmap" of
+ * reasons to sleep. Thus "running" is zero, and
+ * you can test for combinations of others with
+ * simple bit tests.
+ */
+static const char * const task_state_array[] = {
+
+	/* states in TASK_REPORT: */
+	"R (running)",		/* 0x00 */
+	"S (sleeping)",		/* 0x01 */
+	"D (disk sleep)",	/* 0x02 */
+	"T (stopped)",		/* 0x04 */
+	"t (tracing stop)",	/* 0x08 */
+	"X (dead)",		/* 0x10 */
+	"Z (zombie)",		/* 0x20 */
+	"P (parked)",		/* 0x40 */
+
+	/* states beyond TASK_REPORT: */
+	"I (idle)",		/* 0x80 */
+};
+
+static inline const char *get_task_state(struct task_struct *tsk)
+{
+	BUILD_BUG_ON(1 + ilog2(TASK_REPORT_MAX) != ARRAY_SIZE(task_state_array));
+	return task_state_array[task_state_index(tsk)];
+}
+
+static inline void task_state(struct seq_file *m, struct pid_namespace *ns,
+				struct pid *pid, struct task_struct *p)
+{
+	struct user_namespace *user_ns = seq_user_ns(m);
+	struct group_info *group_info;
+	int g, umask = -1;
+	struct task_struct *tracer;
+	const struct cred *cred;
+	pid_t ppid, tpid = 0, tgid, ngid;
+	unsigned int max_fds = 0;
+
+	rcu_read_lock();
+	ppid = pid_alive(p) ?
+		task_tgid_nr_ns(rcu_dereference(p->real_parent), ns) : 0;
+
+	tracer = ptrace_parent(p);
+	if (tracer)
+		tpid = task_pid_nr_ns(tracer, ns);
+
+	tgid = task_tgid_nr_ns(p, ns);
+	ngid = task_numa_group_id(p);
+	cred = get_task_cred(p);
+
+	task_lock(p);
+	if (p->fs)
+		umask = p->fs->umask;
+	if (p->files)
+		max_fds = files_fdtable(p->files)->max_fds;
+	task_unlock(p);
+	rcu_read_unlock();
+
+	if (umask >= 0)
+		seq_printf(m, "Umask:\t%#04o\n", umask);
+	seq_puts(m, "State:\t");
+	seq_puts(m, get_task_state(p));
+
+	seq_put_decimal_ull(m, "\nTgid:\t", tgid);
+	seq_put_decimal_ull(m, "\nNgid:\t", ngid);
+	seq_put_decimal_ull(m, "\nPid:\t", pid_nr_ns(pid, ns));
+	seq_put_decimal_ull(m, "\nPPid:\t", ppid);
+	seq_put_decimal_ull(m, "\nTracerPid:\t", tpid);
+	seq_put_decimal_ull(m, "\nUid:\t", from_kuid_munged(user_ns, cred->uid));
+	seq_put_decimal_ull(m, "\t", from_kuid_munged(user_ns, cred->euid));
+	seq_put_decimal_ull(m, "\t", from_kuid_munged(user_ns, cred->suid));
+	seq_put_decimal_ull(m, "\t", from_kuid_munged(user_ns, cred->fsuid));
+	seq_put_decimal_ull(m, "\nGid:\t", from_kgid_munged(user_ns, cred->gid));
+	seq_put_decimal_ull(m, "\t", from_kgid_munged(user_ns, cred->egid));
+	seq_put_decimal_ull(m, "\t", from_kgid_munged(user_ns, cred->sgid));
+	seq_put_decimal_ull(m, "\t", from_kgid_munged(user_ns, cred->fsgid));
+	seq_put_decimal_ull(m, "\nFDSize:\t", max_fds);
+
+	seq_puts(m, "\nGroups:\t");
+	group_info = cred->group_info;
+	for (g = 0; g < group_info->ngroups; g++)
+		seq_put_decimal_ull(m, g ? " " : "",
+				from_kgid_munged(user_ns, group_info->gid[g]));
+	put_cred(cred);
+	/* Trailing space shouldn't have been added in the first place. */
+	seq_putc(m, ' ');
+
+#ifdef CONFIG_PID_NS
+	seq_puts(m, "\nNStgid:");
+	for (g = ns->level; g <= pid->level; g++)
+		seq_put_decimal_ull(m, "\t", task_tgid_nr_ns(p, pid->numbers[g].ns));
+	seq_puts(m, "\nNSpid:");
+	for (g = ns->level; g <= pid->level; g++)
+		seq_put_decimal_ull(m, "\t", task_pid_nr_ns(p, pid->numbers[g].ns));
+	seq_puts(m, "\nNSpgid:");
+	for (g = ns->level; g <= pid->level; g++)
+		seq_put_decimal_ull(m, "\t", task_pgrp_nr_ns(p, pid->numbers[g].ns));
+	seq_puts(m, "\nNSsid:");
+	for (g = ns->level; g <= pid->level; g++)
+		seq_put_decimal_ull(m, "\t", task_session_nr_ns(p, pid->numbers[g].ns));
+#endif
+	seq_putc(m, '\n');
+}
+
+void render_sigset_t(struct seq_file *m, const char *header,
+				sigset_t *set)
+{
+	int i;
+
+	seq_puts(m, header);
+
+	i = _NSIG;
+	do {
+		int x = 0;
+
+		i -= 4;
+		if (sigismember(set, i+1)) x |= 1;
+		if (sigismember(set, i+2)) x |= 2;
+		if (sigismember(set, i+3)) x |= 4;
+		if (sigismember(set, i+4)) x |= 8;
+		seq_putc(m, hex_asc[x]);
+	} while (i >= 4);
+
+	seq_putc(m, '\n');
+}
+
+static void collect_sigign_sigcatch(struct task_struct *p, sigset_t *sigign,
+				    sigset_t *sigcatch)
+{
+	struct k_sigaction *k;
+	int i;
+
+	k = p->sighand->action;
+	for (i = 1; i <= _NSIG; ++i, ++k) {
+		if (k->sa.sa_handler == SIG_IGN)
+			sigaddset(sigign, i);
+		else if (k->sa.sa_handler != SIG_DFL)
+			sigaddset(sigcatch, i);
+	}
+}
+
+static inline void task_sig(struct seq_file *m, struct task_struct *p)
+{
+	unsigned long flags;
+	sigset_t pending, shpending, blocked, ignored, caught;
+	int num_threads = 0;
+	unsigned int qsize = 0;
+	unsigned long qlim = 0;
+
+	sigemptyset(&pending);
+	sigemptyset(&shpending);
+	sigemptyset(&blocked);
+	sigemptyset(&ignored);
+	sigemptyset(&caught);
+
+	if (lock_task_sighand(p, &flags)) {
+		pending = p->pending.signal;
+		shpending = p->signal->shared_pending.signal;
+		blocked = p->blocked;
+		collect_sigign_sigcatch(p, &ignored, &caught);
+		num_threads = get_nr_threads(p);
+		rcu_read_lock();  /* FIXME: is this correct? */
+		qsize = get_rlimit_value(task_ucounts(p), UCOUNT_RLIMIT_SIGPENDING);
+		rcu_read_unlock();
+		qlim = task_rlimit(p, RLIMIT_SIGPENDING);
+		unlock_task_sighand(p, &flags);
+	}
+
+	seq_put_decimal_ull(m, "Threads:\t", num_threads);
+	seq_put_decimal_ull(m, "\nSigQ:\t", qsize);
+	seq_put_decimal_ull(m, "/", qlim);
+
+	/* render them all */
+	render_sigset_t(m, "\nSigPnd:\t", &pending);
+	render_sigset_t(m, "ShdPnd:\t", &shpending);
+	render_sigset_t(m, "SigBlk:\t", &blocked);
+	render_sigset_t(m, "SigIgn:\t", &ignored);
+	render_sigset_t(m, "SigCgt:\t", &caught);
+}
+
+static void render_cap_t(struct seq_file *m, const char *header,
+			kernel_cap_t *a)
+{
+	unsigned __capi;
+
+	seq_puts(m, header);
+	CAP_FOR_EACH_U32(__capi) {
+		seq_put_hex_ll(m, NULL,
+			   a->cap[CAP_LAST_U32 - __capi], 8);
+	}
+	seq_putc(m, '\n');
+}
+
+static inline void task_cap(struct seq_file *m, struct task_struct *p)
+{
+	const struct cred *cred;
+	kernel_cap_t cap_inheritable, cap_permitted, cap_effective,
+			cap_bset, cap_ambient;
+
+	rcu_read_lock();
+	cred = __task_cred(p);
+	cap_inheritable	= cred->cap_inheritable;
+	cap_permitted	= cred->cap_permitted;
+	cap_effective	= cred->cap_effective;
+	cap_bset	= cred->cap_bset;
+	cap_ambient	= cred->cap_ambient;
+	rcu_read_unlock();
+
+	render_cap_t(m, "CapInh:\t", &cap_inheritable);
+	render_cap_t(m, "CapPrm:\t", &cap_permitted);
+	render_cap_t(m, "CapEff:\t", &cap_effective);
+	render_cap_t(m, "CapBnd:\t", &cap_bset);
+	render_cap_t(m, "CapAmb:\t", &cap_ambient);
+}
+
+static inline void task_seccomp(struct seq_file *m, struct task_struct *p)
+{
+	seq_put_decimal_ull(m, "NoNewPrivs:\t", task_no_new_privs(p));
+#ifdef CONFIG_SECCOMP
+	seq_put_decimal_ull(m, "\nSeccomp:\t", p->seccomp.mode);
+#ifdef CONFIG_SECCOMP_FILTER
+	seq_put_decimal_ull(m, "\nSeccomp_filters:\t",
+			    atomic_read(&p->seccomp.filter_count));
+#endif
+#endif
+	seq_puts(m, "\nSpeculation_Store_Bypass:\t");
+	switch (arch_prctl_spec_ctrl_get(p, PR_SPEC_STORE_BYPASS)) {
+	case -EINVAL:
+		seq_puts(m, "unknown");
+		break;
+	case PR_SPEC_NOT_AFFECTED:
+		seq_puts(m, "not vulnerable");
+		break;
+	case PR_SPEC_PRCTL | PR_SPEC_FORCE_DISABLE:
+		seq_puts(m, "thread force mitigated");
+		break;
+	case PR_SPEC_PRCTL | PR_SPEC_DISABLE:
+		seq_puts(m, "thread mitigated");
+		break;
+	case PR_SPEC_PRCTL | PR_SPEC_ENABLE:
+		seq_puts(m, "thread vulnerable");
+		break;
+	case PR_SPEC_DISABLE:
+		seq_puts(m, "globally mitigated");
+		break;
+	default:
+		seq_puts(m, "vulnerable");
+		break;
+	}
+
+	seq_puts(m, "\nSpeculationIndirectBranch:\t");
+	switch (arch_prctl_spec_ctrl_get(p, PR_SPEC_INDIRECT_BRANCH)) {
+	case -EINVAL:
+		seq_puts(m, "unsupported");
+		break;
+	case PR_SPEC_NOT_AFFECTED:
+		seq_puts(m, "not affected");
+		break;
+	case PR_SPEC_PRCTL | PR_SPEC_FORCE_DISABLE:
+		seq_puts(m, "conditional force disabled");
+		break;
+	case PR_SPEC_PRCTL | PR_SPEC_DISABLE:
+		seq_puts(m, "conditional disabled");
+		break;
+	case PR_SPEC_PRCTL | PR_SPEC_ENABLE:
+		seq_puts(m, "conditional enabled");
+		break;
+	case PR_SPEC_ENABLE:
+		seq_puts(m, "always enabled");
+		break;
+	case PR_SPEC_DISABLE:
+		seq_puts(m, "always disabled");
+		break;
+	default:
+		seq_puts(m, "unknown");
+		break;
+	}
+	seq_putc(m, '\n');
+}
+
+static inline void task_context_switch_counts(struct seq_file *m,
+						struct task_struct *p)
+{
+	seq_put_decimal_ull(m, "voluntary_ctxt_switches:\t", p->nvcsw);
+	seq_put_decimal_ull(m, "\nnonvoluntary_ctxt_switches:\t", p->nivcsw);
+	seq_putc(m, '\n');
+}
+
+static void task_cpus_allowed(struct seq_file *m, struct task_struct *task)
+{
+	seq_printf(m, "Cpus_allowed:\t%*pb\n",
+		   cpumask_pr_args(&task->cpus_mask));
+	seq_printf(m, "Cpus_allowed_list:\t%*pbl\n",
+		   cpumask_pr_args(&task->cpus_mask));
+}
+
+static inline void task_core_dumping(struct seq_file *m, struct task_struct *task)
+{
+	seq_put_decimal_ull(m, "CoreDumping:\t", !!task->signal->core_state);
+	seq_putc(m, '\n');
+}
+
+static inline void task_thp_status(struct seq_file *m, struct mm_struct *mm)
+{
+	bool thp_enabled = IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE);
+
+	if (thp_enabled)
+		thp_enabled = !test_bit(MMF_DISABLE_THP, &mm->flags);
+	seq_printf(m, "THP_enabled:\t%d\n", thp_enabled);
+}
+
+int proc_pid_status(struct seq_file *m, struct pid_namespace *ns,
+			struct pid *pid, struct task_struct *task)
+{
+	struct mm_struct *mm = get_task_mm(task);
+
+	seq_puts(m, "Name:\t");
+	proc_task_name(m, task, true);
+	seq_putc(m, '\n');
+
+	task_state(m, ns, pid, task);
+
+	if (mm) {
+		task_mem(m, mm);
+		task_core_dumping(m, task);
+		task_thp_status(m, mm);
+		mmput(mm);
+	}
+	task_sig(m, task);
+	task_cap(m, task);
+	task_seccomp(m, task);
+	task_cpus_allowed(m, task);
+	cpuset_task_status_allowed(m, task);
+	task_context_switch_counts(m, task);
+	return 0;
+}
+
+static int do_task_stat(struct seq_file *m, struct pid_namespace *ns,
+			struct pid *pid, struct task_struct *task, int whole)
+{
+	unsigned long vsize, eip, esp, wchan = 0;
+	int priority, nice;
+	int tty_pgrp = -1, tty_nr = 0;
+	sigset_t sigign, sigcatch;
+	char state;
+	pid_t ppid = 0, pgid = -1, sid = -1;
+	int num_threads = 0;
+	int permitted;
+	struct mm_struct *mm;
+	unsigned long long start_time;
+	unsigned long cmin_flt = 0, cmaj_flt = 0;
+	unsigned long  min_flt = 0,  maj_flt = 0;
+	u64 cutime, cstime, utime, stime;
+	u64 cgtime, gtime;
+	unsigned long rsslim = 0;
+	unsigned long flags;
+	int exit_code = task->exit_code;
+
+	state = *get_task_state(task);
+	vsize = eip = esp = 0;
+	permitted = ptrace_may_access(task, PTRACE_MODE_READ_FSCREDS | PTRACE_MODE_NOAUDIT);
+	mm = get_task_mm(task);
+	if (mm) {
+		vsize = task_vsize(mm);
+		/*
+		 * esp and eip are intentionally zeroed out.  There is no
+		 * non-racy way to read them without freezing the task.
+		 * Programs that need reliable values can use ptrace(2).
+		 *
+		 * The only exception is if the task is core dumping because
+		 * a program is not able to use ptrace(2) in that case. It is
+		 * safe because the task has stopped executing permanently.
+		 */
+		if (permitted && (task->flags & (PF_EXITING|PF_DUMPCORE))) {
+			if (try_get_task_stack(task)) {
+				eip = KSTK_EIP(task);
+				esp = KSTK_ESP(task);
+				put_task_stack(task);
+			}
+		}
+	}
+
+	sigemptyset(&sigign);
+	sigemptyset(&sigcatch);
+	cutime = cstime = utime = stime = 0;
+	cgtime = gtime = 0;
+
+	if (lock_task_sighand(task, &flags)) {
+		struct signal_struct *sig = task->signal;
+
+		if (sig->tty) {
+			struct pid *pgrp = tty_get_pgrp(sig->tty);
+			tty_pgrp = pid_nr_ns(pgrp, ns);
+			put_pid(pgrp);
+			tty_nr = new_encode_dev(tty_devnum(sig->tty));
+		}
+
+		num_threads = get_nr_threads(task);
+		collect_sigign_sigcatch(task, &sigign, &sigcatch);
+
+		cmin_flt = sig->cmin_flt;
+		cmaj_flt = sig->cmaj_flt;
+		cutime = sig->cutime;
+		cstime = sig->cstime;
+		cgtime = sig->cgtime;
+		rsslim = READ_ONCE(sig->rlim[RLIMIT_RSS].rlim_cur);
+
+		/* add up live thread stats at the group level */
+		if (whole) {
+			struct task_struct *t = task;
+			do {
+				min_flt += t->min_flt;
+				maj_flt += t->maj_flt;
+				gtime += task_gtime(t);
+			} while_each_thread(task, t);
+
+			min_flt += sig->min_flt;
+			maj_flt += sig->maj_flt;
+			thread_group_cputime_adjusted(task, &utime, &stime);
+			gtime += sig->gtime;
+
+			if (sig->flags & (SIGNAL_GROUP_EXIT | SIGNAL_STOP_STOPPED))
+				exit_code = sig->group_exit_code;
+		}
+
+		sid = task_session_nr_ns(task, ns);
+		ppid = task_tgid_nr_ns(task->real_parent, ns);
+		pgid = task_pgrp_nr_ns(task, ns);
+
+		unlock_task_sighand(task, &flags);
+	}
+
+	if (permitted && (!whole || num_threads < 2))
+		wchan = !task_is_running(task);
+	if (!whole) {
+		min_flt = task->min_flt;
+		maj_flt = task->maj_flt;
+		task_cputime_adjusted(task, &utime, &stime);
+		gtime = task_gtime(task);
+	}
+
+	/* scale priority and nice values from timeslices to -20..20 */
+	/* to make it look like a "normal" Unix priority/nice value  */
+	priority = task_prio(task);
+	nice = task_nice(task);
+
+	/* apply timens offset for boottime and convert nsec -> ticks */
+	start_time =
+		nsec_to_clock_t(timens_add_boottime_ns(task->start_boottime));
+
+	seq_put_decimal_ull(m, "", pid_nr_ns(pid, ns));
+	seq_puts(m, " (");
+	proc_task_name(m, task, false);
+	seq_puts(m, ") ");
+	seq_putc(m, state);
+	seq_put_decimal_ll(m, " ", ppid);
+	seq_put_decimal_ll(m, " ", pgid);
+	seq_put_decimal_ll(m, " ", sid);
+	seq_put_decimal_ll(m, " ", tty_nr);
+	seq_put_decimal_ll(m, " ", tty_pgrp);
+	seq_put_decimal_ull(m, " ", task->flags);
+	seq_put_decimal_ull(m, " ", min_flt);
+	seq_put_decimal_ull(m, " ", cmin_flt);
+	seq_put_decimal_ull(m, " ", maj_flt);
+	seq_put_decimal_ull(m, " ", cmaj_flt);
+	seq_put_decimal_ull(m, " ", nsec_to_clock_t(utime));
+	seq_put_decimal_ull(m, " ", nsec_to_clock_t(stime));
+	seq_put_decimal_ll(m, " ", nsec_to_clock_t(cutime));
+	seq_put_decimal_ll(m, " ", nsec_to_clock_t(cstime));
+	seq_put_decimal_ll(m, " ", priority);
+	seq_put_decimal_ll(m, " ", nice);
+	seq_put_decimal_ll(m, " ", num_threads);
+	seq_put_decimal_ull(m, " ", 0);
+	seq_put_decimal_ull(m, " ", start_time);
+	seq_put_decimal_ull(m, " ", vsize);
+	seq_put_decimal_ull(m, " ", mm ? get_mm_rss(mm) : 0);
+	seq_put_decimal_ull(m, " ", rsslim);
+	seq_put_decimal_ull(m, " ", mm ? (permitted ? mm->start_code : 1) : 0);
+	seq_put_decimal_ull(m, " ", mm ? (permitted ? mm->end_code : 1) : 0);
+	seq_put_decimal_ull(m, " ", (permitted && mm) ? mm->start_stack : 0);
+	seq_put_decimal_ull(m, " ", esp);
+	seq_put_decimal_ull(m, " ", eip);
+	/* The signal information here is obsolete.
+	 * It must be decimal for Linux 2.0 compatibility.
+	 * Use /proc/#/status for real-time signals.
+	 */
+	seq_put_decimal_ull(m, " ", task->pending.signal.sig[0] & 0x7fffffffUL);
+	seq_put_decimal_ull(m, " ", task->blocked.sig[0] & 0x7fffffffUL);
+	seq_put_decimal_ull(m, " ", sigign.sig[0] & 0x7fffffffUL);
+	seq_put_decimal_ull(m, " ", sigcatch.sig[0] & 0x7fffffffUL);
+
+	/*
+	 * We used to output the absolute kernel address, but that's an
+	 * information leak - so instead we show a 0/1 flag here, to signal
+	 * to user-space whether there's a wchan field in /proc/PID/wchan.
+	 *
+	 * This works with older implementations of procps as well.
+	 */
+	seq_put_decimal_ull(m, " ", wchan);
+
+	seq_put_decimal_ull(m, " ", 0);
+	seq_put_decimal_ull(m, " ", 0);
+	seq_put_decimal_ll(m, " ", task->exit_signal);
+	seq_put_decimal_ll(m, " ", task_cpu(task));
+	seq_put_decimal_ull(m, " ", task->rt_priority);
+	seq_put_decimal_ull(m, " ", task->policy);
+	seq_put_decimal_ull(m, " ", delayacct_blkio_ticks(task));
+	seq_put_decimal_ull(m, " ", nsec_to_clock_t(gtime));
+	seq_put_decimal_ll(m, " ", nsec_to_clock_t(cgtime));
+
+	if (mm && permitted) {
+		seq_put_decimal_ull(m, " ", mm->start_data);
+		seq_put_decimal_ull(m, " ", mm->end_data);
+		seq_put_decimal_ull(m, " ", mm->start_brk);
+		seq_put_decimal_ull(m, " ", mm->arg_start);
+		seq_put_decimal_ull(m, " ", mm->arg_end);
+		seq_put_decimal_ull(m, " ", mm->env_start);
+		seq_put_decimal_ull(m, " ", mm->env_end);
+	} else
+		seq_puts(m, " 0 0 0 0 0 0 0");
+
+	if (permitted)
+		seq_put_decimal_ll(m, " ", exit_code);
+	else
+		seq_puts(m, " 0");
+
+	seq_putc(m, '\n');
+	if (mm)
+		mmput(mm);
+	return 0;
+}
+
+int proc_tid_stat(struct seq_file *m, struct pid_namespace *ns,
+			struct pid *pid, struct task_struct *task)
+{
+	return do_task_stat(m, ns, pid, task, 0);
+}
+
+int proc_tgid_stat(struct seq_file *m, struct pid_namespace *ns,
+			struct pid *pid, struct task_struct *task)
+{
+	return do_task_stat(m, ns, pid, task, 1);
+}
+
+int proc_pid_statm(struct seq_file *m, struct pid_namespace *ns,
+			struct pid *pid, struct task_struct *task)
+{
+	struct mm_struct *mm = get_task_mm(task);
+
+	if (mm) {
+		unsigned long size;
+		unsigned long resident = 0;
+		unsigned long shared = 0;
+		unsigned long text = 0;
+		unsigned long data = 0;
+
+		size = task_statm(mm, &shared, &text, &data, &resident);
+		mmput(mm);
+
+		/*
+		 * For quick read, open code by putting numbers directly
+		 * expected format is
+		 * seq_printf(m, "%lu %lu %lu %lu 0 %lu 0\n",
+		 *               size, resident, shared, text, data);
+		 */
+		seq_put_decimal_ull(m, "", size);
+		seq_put_decimal_ull(m, " ", resident);
+		seq_put_decimal_ull(m, " ", shared);
+		seq_put_decimal_ull(m, " ", text);
+		seq_put_decimal_ull(m, " ", 0);
+		seq_put_decimal_ull(m, " ", data);
+		seq_put_decimal_ull(m, " ", 0);
+		seq_putc(m, '\n');
+	} else {
+		seq_write(m, "0 0 0 0 0 0 0\n", 14);
+	}
+	return 0;
+}
+
+#ifdef CONFIG_PROC_CHILDREN
+static struct pid *
+get_children_pid(struct inode *inode, struct pid *pid_prev, loff_t pos)
+{
+	struct task_struct *start, *task;
+	struct pid *pid = NULL;
+
+	read_lock(&tasklist_lock);
+
+	start = pid_task(proc_pid(inode), PIDTYPE_PID);
+	if (!start)
+		goto out;
+
+	/*
+	 * Lets try to continue searching first, this gives
+	 * us significant speedup on children-rich processes.
+	 */
+	if (pid_prev) {
+		task = pid_task(pid_prev, PIDTYPE_PID);
+		if (task && task->real_parent == start &&
+		    !(list_empty(&task->sibling))) {
+			if (list_is_last(&task->sibling, &start->children))
+				goto out;
+			task = list_first_entry(&task->sibling,
+						struct task_struct, sibling);
+			pid = get_pid(task_pid(task));
+			goto out;
+		}
+	}
+
+	/*
+	 * Slow search case.
+	 *
+	 * We might miss some children here if children
+	 * are exited while we were not holding the lock,
+	 * but it was never promised to be accurate that
+	 * much.
+	 *
+	 * "Just suppose that the parent sleeps, but N children
+	 *  exit after we printed their tids. Now the slow paths
+	 *  skips N extra children, we miss N tasks." (c)
+	 *
+	 * So one need to stop or freeze the leader and all
+	 * its children to get a precise result.
+	 */
+	list_for_each_entry(task, &start->children, sibling) {
+		if (pos-- == 0) {
+			pid = get_pid(task_pid(task));
+			break;
+		}
+	}
+
+out:
+	read_unlock(&tasklist_lock);
+	return pid;
+}
+
+static int children_seq_show(struct seq_file *seq, void *v)
+{
+	struct inode *inode = file_inode(seq->file);
+
+	seq_printf(seq, "%d ", pid_nr_ns(v, proc_pid_ns(inode->i_sb)));
+	return 0;
+}
+
+static void *children_seq_start(struct seq_file *seq, loff_t *pos)
+{
+	return get_children_pid(file_inode(seq->file), NULL, *pos);
+}
+
+static void *children_seq_next(struct seq_file *seq, void *v, loff_t *pos)
+{
+	struct pid *pid;
+
+	pid = get_children_pid(file_inode(seq->file), v, *pos + 1);
+	put_pid(v);
+
+	++*pos;
+	return pid;
+}
+
+static void children_seq_stop(struct seq_file *seq, void *v)
+{
+	put_pid(v);
+}
+
+static const struct seq_operations children_seq_ops = {
+	.start	= children_seq_start,
+	.next	= children_seq_next,
+	.stop	= children_seq_stop,
+	.show	= children_seq_show,
+};
+
+static int children_seq_open(struct inode *inode, struct file *file)
+{
+	return seq_open(file, &children_seq_ops);
+}
+
+const struct file_operations proc_tid_children_operations = {
+	.open    = children_seq_open,
+	.read    = seq_read,
+	.llseek  = seq_lseek,
+	.release = seq_release,
+};
+#endif /* CONFIG_PROC_CHILDREN */
diff --git a/fs/proc/base.c b/fs/proc/base.c
new file mode 100644
index 000000000..74442e017
--- /dev/null
+++ b/fs/proc/base.c
@@ -0,0 +1,3928 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ *  linux/fs/proc/base.c
+ *
+ *  Copyright (C) 1991, 1992 Linus Torvalds
+ *
+ *  proc base directory handling functions
+ *
+ *  1999, Al Viro. Rewritten. Now it covers the whole per-process part.
+ *  Instead of using magical inumbers to determine the kind of object
+ *  we allocate and fill in-core inodes upon lookup. They don't even
+ *  go into icache. We cache the reference to task_struct upon lookup too.
+ *  Eventually it should become a filesystem in its own. We don't use the
+ *  rest of procfs anymore.
+ *
+ *
+ *  Changelog:
+ *  17-Jan-2005
+ *  Allan Bezerra
+ *  Bruna Moreira <bruna.moreira@indt.org.br>
+ *  Edjard Mota <edjard.mota@indt.org.br>
+ *  Ilias Biris <ilias.biris@indt.org.br>
+ *  Mauricio Lin <mauricio.lin@indt.org.br>
+ *
+ *  Embedded Linux Lab - 10LE Instituto Nokia de Tecnologia - INdT
+ *
+ *  A new process specific entry (smaps) included in /proc. It shows the
+ *  size of rss for each memory area. The maps entry lacks information
+ *  about physical memory size (rss) for each mapped file, i.e.,
+ *  rss information for executables and library files.
+ *  This additional information is useful for any tools that need to know
+ *  about physical memory consumption for a process specific library.
+ *
+ *  Changelog:
+ *  21-Feb-2005
+ *  Embedded Linux Lab - 10LE Instituto Nokia de Tecnologia - INdT
+ *  Pud inclusion in the page table walking.
+ *
+ *  ChangeLog:
+ *  10-Mar-2005
+ *  10LE Instituto Nokia de Tecnologia - INdT:
+ *  A better way to walks through the page table as suggested by Hugh Dickins.
+ *
+ *  Simo Piiroinen <simo.piiroinen@nokia.com>:
+ *  Smaps information related to shared, private, clean and dirty pages.
+ *
+ *  Paul Mundt <paul.mundt@nokia.com>:
+ *  Overall revision about smaps.
+ */
+
+#include <linux/uaccess.h>
+
+#include <linux/errno.h>
+#include <linux/time.h>
+#include <linux/proc_fs.h>
+#include <linux/stat.h>
+#include <linux/task_io_accounting_ops.h>
+#include <linux/init.h>
+#include <linux/capability.h>
+#include <linux/file.h>
+#include <linux/fdtable.h>
+#include <linux/generic-radix-tree.h>
+#include <linux/string.h>
+#include <linux/seq_file.h>
+#include <linux/namei.h>
+#include <linux/mnt_namespace.h>
+#include <linux/mm.h>
+#include <linux/swap.h>
+#include <linux/rcupdate.h>
+#include <linux/kallsyms.h>
+#include <linux/stacktrace.h>
+#include <linux/resource.h>
+#include <linux/module.h>
+#include <linux/mount.h>
+#include <linux/security.h>
+#include <linux/ptrace.h>
+#include <linux/printk.h>
+#include <linux/cache.h>
+#include <linux/cgroup.h>
+#include <linux/cpuset.h>
+#include <linux/audit.h>
+#include <linux/poll.h>
+#include <linux/nsproxy.h>
+#include <linux/oom.h>
+#include <linux/elf.h>
+#include <linux/pid_namespace.h>
+#include <linux/user_namespace.h>
+#include <linux/fs_struct.h>
+#include <linux/slab.h>
+#include <linux/sched/autogroup.h>
+#include <linux/sched/mm.h>
+#include <linux/sched/coredump.h>
+#include <linux/sched/debug.h>
+#include <linux/sched/stat.h>
+#include <linux/posix-timers.h>
+#include <linux/time_namespace.h>
+#include <linux/resctrl.h>
+#include <linux/cn_proc.h>
+#include <trace/events/oom.h>
+#include "internal.h"
+#include "fd.h"
+
+#include "../../lib/kstrtox.h"
+
+/* NOTE:
+ *	Implementing inode permission operations in /proc is almost
+ *	certainly an error.  Permission checks need to happen during
+ *	each system call not at open time.  The reason is that most of
+ *	what we wish to check for permissions in /proc varies at runtime.
+ *
+ *	The classic example of a problem is opening file descriptors
+ *	in /proc for a task before it execs a suid executable.
+ */
+
+static u8 nlink_tid __ro_after_init;
+static u8 nlink_tgid __ro_after_init;
+
+struct pid_entry {
+	const char *name;
+	unsigned int len;
+	umode_t mode;
+	const struct inode_operations *iop;
+	const struct file_operations *fop;
+	union proc_op op;
+};
+
+#define NOD(NAME, MODE, IOP, FOP, OP) {			\
+	.name = (NAME),					\
+	.len  = sizeof(NAME) - 1,			\
+	.mode = MODE,					\
+	.iop  = IOP,					\
+	.fop  = FOP,					\
+	.op   = OP,					\
+}
+
+#define DIR(NAME, MODE, iops, fops)	\
+	NOD(NAME, (S_IFDIR|(MODE)), &iops, &fops, {} )
+#define LNK(NAME, get_link)					\
+	NOD(NAME, (S_IFLNK|S_IRWXUGO),				\
+		&proc_pid_link_inode_operations, NULL,		\
+		{ .proc_get_link = get_link } )
+#define REG(NAME, MODE, fops)				\
+	NOD(NAME, (S_IFREG|(MODE)), NULL, &fops, {})
+#define ONE(NAME, MODE, show)				\
+	NOD(NAME, (S_IFREG|(MODE)),			\
+		NULL, &proc_single_file_operations,	\
+		{ .proc_show = show } )
+#define ATTR(LSM, NAME, MODE)				\
+	NOD(NAME, (S_IFREG|(MODE)),			\
+		NULL, &proc_pid_attr_operations,	\
+		{ .lsm = LSM })
+
+/*
+ * Count the number of hardlinks for the pid_entry table, excluding the .
+ * and .. links.
+ */
+static unsigned int __init pid_entry_nlink(const struct pid_entry *entries,
+	unsigned int n)
+{
+	unsigned int i;
+	unsigned int count;
+
+	count = 2;
+	for (i = 0; i < n; ++i) {
+		if (S_ISDIR(entries[i].mode))
+			++count;
+	}
+
+	return count;
+}
+
+static int get_task_root(struct task_struct *task, struct path *root)
+{
+	int result = -ENOENT;
+
+	task_lock(task);
+	if (task->fs) {
+		get_fs_root(task->fs, root);
+		result = 0;
+	}
+	task_unlock(task);
+	return result;
+}
+
+static int proc_cwd_link(struct dentry *dentry, struct path *path)
+{
+	struct task_struct *task = get_proc_task(d_inode(dentry));
+	int result = -ENOENT;
+
+	if (task) {
+		task_lock(task);
+		if (task->fs) {
+			get_fs_pwd(task->fs, path);
+			result = 0;
+		}
+		task_unlock(task);
+		put_task_struct(task);
+	}
+	return result;
+}
+
+static int proc_root_link(struct dentry *dentry, struct path *path)
+{
+	struct task_struct *task = get_proc_task(d_inode(dentry));
+	int result = -ENOENT;
+
+	if (task) {
+		result = get_task_root(task, path);
+		put_task_struct(task);
+	}
+	return result;
+}
+
+/*
+ * If the user used setproctitle(), we just get the string from
+ * user space at arg_start, and limit it to a maximum of one page.
+ */
+static ssize_t get_mm_proctitle(struct mm_struct *mm, char __user *buf,
+				size_t count, unsigned long pos,
+				unsigned long arg_start)
+{
+	char *page;
+	int ret, got;
+
+	if (pos >= PAGE_SIZE)
+		return 0;
+
+	page = (char *)__get_free_page(GFP_KERNEL);
+	if (!page)
+		return -ENOMEM;
+
+	ret = 0;
+	got = access_remote_vm(mm, arg_start, page, PAGE_SIZE, FOLL_ANON);
+	if (got > 0) {
+		int len = strnlen(page, got);
+
+		/* Include the NUL character if it was found */
+		if (len < got)
+			len++;
+
+		if (len > pos) {
+			len -= pos;
+			if (len > count)
+				len = count;
+			len -= copy_to_user(buf, page+pos, len);
+			if (!len)
+				len = -EFAULT;
+			ret = len;
+		}
+	}
+	free_page((unsigned long)page);
+	return ret;
+}
+
+static ssize_t get_mm_cmdline(struct mm_struct *mm, char __user *buf,
+			      size_t count, loff_t *ppos)
+{
+	unsigned long arg_start, arg_end, env_start, env_end;
+	unsigned long pos, len;
+	char *page, c;
+
+	/* Check if process spawned far enough to have cmdline. */
+	if (!mm->env_end)
+		return 0;
+
+	spin_lock(&mm->arg_lock);
+	arg_start = mm->arg_start;
+	arg_end = mm->arg_end;
+	env_start = mm->env_start;
+	env_end = mm->env_end;
+	spin_unlock(&mm->arg_lock);
+
+	if (arg_start >= arg_end)
+		return 0;
+
+	/*
+	 * We allow setproctitle() to overwrite the argument
+	 * strings, and overflow past the original end. But
+	 * only when it overflows into the environment area.
+	 */
+	if (env_start != arg_end || env_end < env_start)
+		env_start = env_end = arg_end;
+	len = env_end - arg_start;
+
+	/* We're not going to care if "*ppos" has high bits set */
+	pos = *ppos;
+	if (pos >= len)
+		return 0;
+	if (count > len - pos)
+		count = len - pos;
+	if (!count)
+		return 0;
+
+	/*
+	 * Magical special case: if the argv[] end byte is not
+	 * zero, the user has overwritten it with setproctitle(3).
+	 *
+	 * Possible future enhancement: do this only once when
+	 * pos is 0, and set a flag in the 'struct file'.
+	 */
+	if (access_remote_vm(mm, arg_end-1, &c, 1, FOLL_ANON) == 1 && c)
+		return get_mm_proctitle(mm, buf, count, pos, arg_start);
+
+	/*
+	 * For the non-setproctitle() case we limit things strictly
+	 * to the [arg_start, arg_end[ range.
+	 */
+	pos += arg_start;
+	if (pos < arg_start || pos >= arg_end)
+		return 0;
+	if (count > arg_end - pos)
+		count = arg_end - pos;
+
+	page = (char *)__get_free_page(GFP_KERNEL);
+	if (!page)
+		return -ENOMEM;
+
+	len = 0;
+	while (count) {
+		int got;
+		size_t size = min_t(size_t, PAGE_SIZE, count);
+
+		got = access_remote_vm(mm, pos, page, size, FOLL_ANON);
+		if (got <= 0)
+			break;
+		got -= copy_to_user(buf, page, got);
+		if (unlikely(!got)) {
+			if (!len)
+				len = -EFAULT;
+			break;
+		}
+		pos += got;
+		buf += got;
+		len += got;
+		count -= got;
+	}
+
+	free_page((unsigned long)page);
+	return len;
+}
+
+static ssize_t get_task_cmdline(struct task_struct *tsk, char __user *buf,
+				size_t count, loff_t *pos)
+{
+	struct mm_struct *mm;
+	ssize_t ret;
+
+	mm = get_task_mm(tsk);
+	if (!mm)
+		return 0;
+
+	ret = get_mm_cmdline(mm, buf, count, pos);
+	mmput(mm);
+	return ret;
+}
+
+static ssize_t proc_pid_cmdline_read(struct file *file, char __user *buf,
+				     size_t count, loff_t *pos)
+{
+	struct task_struct *tsk;
+	ssize_t ret;
+
+	BUG_ON(*pos < 0);
+
+	tsk = get_proc_task(file_inode(file));
+	if (!tsk)
+		return -ESRCH;
+	ret = get_task_cmdline(tsk, buf, count, pos);
+	put_task_struct(tsk);
+	if (ret > 0)
+		*pos += ret;
+	return ret;
+}
+
+static const struct file_operations proc_pid_cmdline_ops = {
+	.read	= proc_pid_cmdline_read,
+	.llseek	= generic_file_llseek,
+};
+
+#ifdef CONFIG_KALLSYMS
+/*
+ * Provides a wchan file via kallsyms in a proper one-value-per-file format.
+ * Returns the resolved symbol.  If that fails, simply return the address.
+ */
+static int proc_pid_wchan(struct seq_file *m, struct pid_namespace *ns,
+			  struct pid *pid, struct task_struct *task)
+{
+	unsigned long wchan;
+	char symname[KSYM_NAME_LEN];
+
+	if (!ptrace_may_access(task, PTRACE_MODE_READ_FSCREDS))
+		goto print0;
+
+	wchan = get_wchan(task);
+	if (wchan && !lookup_symbol_name(wchan, symname)) {
+		seq_puts(m, symname);
+		return 0;
+	}
+
+print0:
+	seq_putc(m, '0');
+	return 0;
+}
+#endif /* CONFIG_KALLSYMS */
+
+static int lock_trace(struct task_struct *task)
+{
+	int err = down_read_killable(&task->signal->exec_update_lock);
+	if (err)
+		return err;
+	if (!ptrace_may_access(task, PTRACE_MODE_ATTACH_FSCREDS)) {
+		up_read(&task->signal->exec_update_lock);
+		return -EPERM;
+	}
+	return 0;
+}
+
+static void unlock_trace(struct task_struct *task)
+{
+	up_read(&task->signal->exec_update_lock);
+}
+
+#ifdef CONFIG_STACKTRACE
+
+#define MAX_STACK_TRACE_DEPTH	64
+
+static int proc_pid_stack(struct seq_file *m, struct pid_namespace *ns,
+			  struct pid *pid, struct task_struct *task)
+{
+	unsigned long *entries;
+	int err;
+
+	/*
+	 * The ability to racily run the kernel stack unwinder on a running task
+	 * and then observe the unwinder output is scary; while it is useful for
+	 * debugging kernel issues, it can also allow an attacker to leak kernel
+	 * stack contents.
+	 * Doing this in a manner that is at least safe from races would require
+	 * some work to ensure that the remote task can not be scheduled; and
+	 * even then, this would still expose the unwinder as local attack
+	 * surface.
+	 * Therefore, this interface is restricted to root.
+	 */
+	if (!file_ns_capable(m->file, &init_user_ns, CAP_SYS_ADMIN))
+		return -EACCES;
+
+	entries = kmalloc_array(MAX_STACK_TRACE_DEPTH, sizeof(*entries),
+				GFP_KERNEL);
+	if (!entries)
+		return -ENOMEM;
+
+	err = lock_trace(task);
+	if (!err) {
+		unsigned int i, nr_entries;
+
+		nr_entries = stack_trace_save_tsk(task, entries,
+						  MAX_STACK_TRACE_DEPTH, 0);
+
+		for (i = 0; i < nr_entries; i++) {
+			seq_printf(m, "[<0>] %pB\n", (void *)entries[i]);
+		}
+
+		unlock_trace(task);
+	}
+	kfree(entries);
+
+	return err;
+}
+#endif
+
+#ifdef CONFIG_SCHED_INFO
+/*
+ * Provides /proc/PID/schedstat
+ */
+static int proc_pid_schedstat(struct seq_file *m, struct pid_namespace *ns,
+			      struct pid *pid, struct task_struct *task)
+{
+	if (unlikely(!sched_info_on()))
+		seq_puts(m, "0 0 0\n");
+	else
+		seq_printf(m, "%llu %llu %lu\n",
+		   (unsigned long long)task->se.sum_exec_runtime,
+		   (unsigned long long)task->sched_info.run_delay,
+		   task->sched_info.pcount);
+
+	return 0;
+}
+#endif
+
+#ifdef CONFIG_LATENCYTOP
+static int lstats_show_proc(struct seq_file *m, void *v)
+{
+	int i;
+	struct inode *inode = m->private;
+	struct task_struct *task = get_proc_task(inode);
+
+	if (!task)
+		return -ESRCH;
+	seq_puts(m, "Latency Top version : v0.1\n");
+	for (i = 0; i < LT_SAVECOUNT; i++) {
+		struct latency_record *lr = &task->latency_record[i];
+		if (lr->backtrace[0]) {
+			int q;
+			seq_printf(m, "%i %li %li",
+				   lr->count, lr->time, lr->max);
+			for (q = 0; q < LT_BACKTRACEDEPTH; q++) {
+				unsigned long bt = lr->backtrace[q];
+
+				if (!bt)
+					break;
+				seq_printf(m, " %ps", (void *)bt);
+			}
+			seq_putc(m, '\n');
+		}
+
+	}
+	put_task_struct(task);
+	return 0;
+}
+
+static int lstats_open(struct inode *inode, struct file *file)
+{
+	return single_open(file, lstats_show_proc, inode);
+}
+
+static ssize_t lstats_write(struct file *file, const char __user *buf,
+			    size_t count, loff_t *offs)
+{
+	struct task_struct *task = get_proc_task(file_inode(file));
+
+	if (!task)
+		return -ESRCH;
+	clear_tsk_latency_tracing(task);
+	put_task_struct(task);
+
+	return count;
+}
+
+static const struct file_operations proc_lstats_operations = {
+	.open		= lstats_open,
+	.read		= seq_read,
+	.write		= lstats_write,
+	.llseek		= seq_lseek,
+	.release	= single_release,
+};
+
+#endif
+
+static int proc_oom_score(struct seq_file *m, struct pid_namespace *ns,
+			  struct pid *pid, struct task_struct *task)
+{
+	unsigned long totalpages = totalram_pages() + total_swap_pages;
+	unsigned long points = 0;
+	long badness;
+
+	badness = oom_badness(task, totalpages);
+	/*
+	 * Special case OOM_SCORE_ADJ_MIN for all others scale the
+	 * badness value into [0, 2000] range which we have been
+	 * exporting for a long time so userspace might depend on it.
+	 */
+	if (badness != LONG_MIN)
+		points = (1000 + badness * 1000 / (long)totalpages) * 2 / 3;
+
+	seq_printf(m, "%lu\n", points);
+
+	return 0;
+}
+
+struct limit_names {
+	const char *name;
+	const char *unit;
+};
+
+static const struct limit_names lnames[RLIM_NLIMITS] = {
+	[RLIMIT_CPU] = {"Max cpu time", "seconds"},
+	[RLIMIT_FSIZE] = {"Max file size", "bytes"},
+	[RLIMIT_DATA] = {"Max data size", "bytes"},
+	[RLIMIT_STACK] = {"Max stack size", "bytes"},
+	[RLIMIT_CORE] = {"Max core file size", "bytes"},
+	[RLIMIT_RSS] = {"Max resident set", "bytes"},
+	[RLIMIT_NPROC] = {"Max processes", "processes"},
+	[RLIMIT_NOFILE] = {"Max open files", "files"},
+	[RLIMIT_MEMLOCK] = {"Max locked memory", "bytes"},
+	[RLIMIT_AS] = {"Max address space", "bytes"},
+	[RLIMIT_LOCKS] = {"Max file locks", "locks"},
+	[RLIMIT_SIGPENDING] = {"Max pending signals", "signals"},
+	[RLIMIT_MSGQUEUE] = {"Max msgqueue size", "bytes"},
+	[RLIMIT_NICE] = {"Max nice priority", NULL},
+	[RLIMIT_RTPRIO] = {"Max realtime priority", NULL},
+	[RLIMIT_RTTIME] = {"Max realtime timeout", "us"},
+};
+
+/* Display limits for a process */
+static int proc_pid_limits(struct seq_file *m, struct pid_namespace *ns,
+			   struct pid *pid, struct task_struct *task)
+{
+	unsigned int i;
+	unsigned long flags;
+
+	struct rlimit rlim[RLIM_NLIMITS];
+
+	if (!lock_task_sighand(task, &flags))
+		return 0;
+	memcpy(rlim, task->signal->rlim, sizeof(struct rlimit) * RLIM_NLIMITS);
+	unlock_task_sighand(task, &flags);
+
+	/*
+	 * print the file header
+	 */
+	seq_puts(m, "Limit                     "
+		"Soft Limit           "
+		"Hard Limit           "
+		"Units     \n");
+
+	for (i = 0; i < RLIM_NLIMITS; i++) {
+		if (rlim[i].rlim_cur == RLIM_INFINITY)
+			seq_printf(m, "%-25s %-20s ",
+				   lnames[i].name, "unlimited");
+		else
+			seq_printf(m, "%-25s %-20lu ",
+				   lnames[i].name, rlim[i].rlim_cur);
+
+		if (rlim[i].rlim_max == RLIM_INFINITY)
+			seq_printf(m, "%-20s ", "unlimited");
+		else
+			seq_printf(m, "%-20lu ", rlim[i].rlim_max);
+
+		if (lnames[i].unit)
+			seq_printf(m, "%-10s\n", lnames[i].unit);
+		else
+			seq_putc(m, '\n');
+	}
+
+	return 0;
+}
+
+#ifdef CONFIG_HAVE_ARCH_TRACEHOOK
+static int proc_pid_syscall(struct seq_file *m, struct pid_namespace *ns,
+			    struct pid *pid, struct task_struct *task)
+{
+	struct syscall_info info;
+	u64 *args = &info.data.args[0];
+	int res;
+
+	res = lock_trace(task);
+	if (res)
+		return res;
+
+	if (task_current_syscall(task, &info))
+		seq_puts(m, "running\n");
+	else if (info.data.nr < 0)
+		seq_printf(m, "%d 0x%llx 0x%llx\n",
+			   info.data.nr, info.sp, info.data.instruction_pointer);
+	else
+		seq_printf(m,
+		       "%d 0x%llx 0x%llx 0x%llx 0x%llx 0x%llx 0x%llx 0x%llx 0x%llx\n",
+		       info.data.nr,
+		       args[0], args[1], args[2], args[3], args[4], args[5],
+		       info.sp, info.data.instruction_pointer);
+	unlock_trace(task);
+
+	return 0;
+}
+#endif /* CONFIG_HAVE_ARCH_TRACEHOOK */
+
+/************************************************************************/
+/*                       Here the fs part begins                        */
+/************************************************************************/
+
+/* permission checks */
+static bool proc_fd_access_allowed(struct inode *inode)
+{
+	struct task_struct *task;
+	bool allowed = false;
+	/* Allow access to a task's file descriptors if it is us or we
+	 * may use ptrace attach to the process and find out that
+	 * information.
+	 */
+	task = get_proc_task(inode);
+	if (task) {
+		allowed = ptrace_may_access(task, PTRACE_MODE_READ_FSCREDS);
+		put_task_struct(task);
+	}
+	return allowed;
+}
+
+int proc_setattr(struct user_namespace *mnt_userns, struct dentry *dentry,
+		 struct iattr *attr)
+{
+	int error;
+	struct inode *inode = d_inode(dentry);
+
+	if (attr->ia_valid & ATTR_MODE)
+		return -EPERM;
+
+	error = setattr_prepare(&init_user_ns, dentry, attr);
+	if (error)
+		return error;
+
+	setattr_copy(&init_user_ns, inode, attr);
+	mark_inode_dirty(inode);
+	return 0;
+}
+
+/*
+ * May current process learn task's sched/cmdline info (for hide_pid_min=1)
+ * or euid/egid (for hide_pid_min=2)?
+ */
+static bool has_pid_permissions(struct proc_fs_info *fs_info,
+				 struct task_struct *task,
+				 enum proc_hidepid hide_pid_min)
+{
+	/*
+	 * If 'hidpid' mount option is set force a ptrace check,
+	 * we indicate that we are using a filesystem syscall
+	 * by passing PTRACE_MODE_READ_FSCREDS
+	 */
+	if (fs_info->hide_pid == HIDEPID_NOT_PTRACEABLE)
+		return ptrace_may_access(task, PTRACE_MODE_READ_FSCREDS);
+
+	if (fs_info->hide_pid < hide_pid_min)
+		return true;
+	if (in_group_p(fs_info->pid_gid))
+		return true;
+	return ptrace_may_access(task, PTRACE_MODE_READ_FSCREDS);
+}
+
+
+static int proc_pid_permission(struct user_namespace *mnt_userns,
+			       struct inode *inode, int mask)
+{
+	struct proc_fs_info *fs_info = proc_sb_info(inode->i_sb);
+	struct task_struct *task;
+	bool has_perms;
+
+	task = get_proc_task(inode);
+	if (!task)
+		return -ESRCH;
+	has_perms = has_pid_permissions(fs_info, task, HIDEPID_NO_ACCESS);
+	put_task_struct(task);
+
+	if (!has_perms) {
+		if (fs_info->hide_pid == HIDEPID_INVISIBLE) {
+			/*
+			 * Let's make getdents(), stat(), and open()
+			 * consistent with each other.  If a process
+			 * may not stat() a file, it shouldn't be seen
+			 * in procfs at all.
+			 */
+			return -ENOENT;
+		}
+
+		return -EPERM;
+	}
+	return generic_permission(&init_user_ns, inode, mask);
+}
+
+
+
+static const struct inode_operations proc_def_inode_operations = {
+	.setattr	= proc_setattr,
+};
+
+static int proc_single_show(struct seq_file *m, void *v)
+{
+	struct inode *inode = m->private;
+	struct pid_namespace *ns = proc_pid_ns(inode->i_sb);
+	struct pid *pid = proc_pid(inode);
+	struct task_struct *task;
+	int ret;
+
+	task = get_pid_task(pid, PIDTYPE_PID);
+	if (!task)
+		return -ESRCH;
+
+	ret = PROC_I(inode)->op.proc_show(m, ns, pid, task);
+
+	put_task_struct(task);
+	return ret;
+}
+
+static int proc_single_open(struct inode *inode, struct file *filp)
+{
+	return single_open(filp, proc_single_show, inode);
+}
+
+static const struct file_operations proc_single_file_operations = {
+	.open		= proc_single_open,
+	.read		= seq_read,
+	.llseek		= seq_lseek,
+	.release	= single_release,
+};
+
+
+struct mm_struct *proc_mem_open(struct inode *inode, unsigned int mode)
+{
+	struct task_struct *task = get_proc_task(inode);
+	struct mm_struct *mm = ERR_PTR(-ESRCH);
+
+	if (task) {
+		mm = mm_access(task, mode | PTRACE_MODE_FSCREDS);
+		put_task_struct(task);
+
+		if (!IS_ERR_OR_NULL(mm)) {
+			/* ensure this mm_struct can't be freed */
+			mmgrab(mm);
+			/* but do not pin its memory */
+			mmput(mm);
+		}
+	}
+
+	return mm;
+}
+
+static int __mem_open(struct inode *inode, struct file *file, unsigned int mode)
+{
+	struct mm_struct *mm = proc_mem_open(inode, mode);
+
+	if (IS_ERR(mm))
+		return PTR_ERR(mm);
+
+	file->private_data = mm;
+	return 0;
+}
+
+static int mem_open(struct inode *inode, struct file *file)
+{
+	int ret = __mem_open(inode, file, PTRACE_MODE_ATTACH);
+
+	/* OK to pass negative loff_t, we can catch out-of-range */
+	file->f_mode |= FMODE_UNSIGNED_OFFSET;
+
+	return ret;
+}
+
+static ssize_t mem_rw(struct file *file, char __user *buf,
+			size_t count, loff_t *ppos, int write)
+{
+	struct mm_struct *mm = file->private_data;
+	unsigned long addr = *ppos;
+	ssize_t copied;
+	char *page;
+	unsigned int flags;
+
+	if (!mm)
+		return 0;
+
+	page = (char *)__get_free_page(GFP_KERNEL);
+	if (!page)
+		return -ENOMEM;
+
+	copied = 0;
+	if (!mmget_not_zero(mm))
+		goto free;
+
+	flags = FOLL_FORCE | (write ? FOLL_WRITE : 0);
+
+	while (count > 0) {
+		size_t this_len = min_t(size_t, count, PAGE_SIZE);
+
+		if (write && copy_from_user(page, buf, this_len)) {
+			copied = -EFAULT;
+			break;
+		}
+
+		this_len = access_remote_vm(mm, addr, page, this_len, flags);
+		if (!this_len) {
+			if (!copied)
+				copied = -EIO;
+			break;
+		}
+
+		if (!write && copy_to_user(buf, page, this_len)) {
+			copied = -EFAULT;
+			break;
+		}
+
+		buf += this_len;
+		addr += this_len;
+		copied += this_len;
+		count -= this_len;
+	}
+	*ppos = addr;
+
+	mmput(mm);
+free:
+	free_page((unsigned long) page);
+	return copied;
+}
+
+static ssize_t mem_read(struct file *file, char __user *buf,
+			size_t count, loff_t *ppos)
+{
+	return mem_rw(file, buf, count, ppos, 0);
+}
+
+static ssize_t mem_write(struct file *file, const char __user *buf,
+			 size_t count, loff_t *ppos)
+{
+	return mem_rw(file, (char __user*)buf, count, ppos, 1);
+}
+
+loff_t mem_lseek(struct file *file, loff_t offset, int orig)
+{
+	switch (orig) {
+	case 0:
+		file->f_pos = offset;
+		break;
+	case 1:
+		file->f_pos += offset;
+		break;
+	default:
+		return -EINVAL;
+	}
+	force_successful_syscall_return();
+	return file->f_pos;
+}
+
+static int mem_release(struct inode *inode, struct file *file)
+{
+	struct mm_struct *mm = file->private_data;
+	if (mm)
+		mmdrop(mm);
+	return 0;
+}
+
+static const struct file_operations proc_mem_operations = {
+	.llseek		= mem_lseek,
+	.read		= mem_read,
+	.write		= mem_write,
+	.open		= mem_open,
+	.release	= mem_release,
+};
+
+static int environ_open(struct inode *inode, struct file *file)
+{
+	return __mem_open(inode, file, PTRACE_MODE_READ);
+}
+
+static ssize_t environ_read(struct file *file, char __user *buf,
+			size_t count, loff_t *ppos)
+{
+	char *page;
+	unsigned long src = *ppos;
+	int ret = 0;
+	struct mm_struct *mm = file->private_data;
+	unsigned long env_start, env_end;
+
+	/* Ensure the process spawned far enough to have an environment. */
+	if (!mm || !mm->env_end)
+		return 0;
+
+	page = (char *)__get_free_page(GFP_KERNEL);
+	if (!page)
+		return -ENOMEM;
+
+	ret = 0;
+	if (!mmget_not_zero(mm))
+		goto free;
+
+	spin_lock(&mm->arg_lock);
+	env_start = mm->env_start;
+	env_end = mm->env_end;
+	spin_unlock(&mm->arg_lock);
+
+	while (count > 0) {
+		size_t this_len, max_len;
+		int retval;
+
+		if (src >= (env_end - env_start))
+			break;
+
+		this_len = env_end - (env_start + src);
+
+		max_len = min_t(size_t, PAGE_SIZE, count);
+		this_len = min(max_len, this_len);
+
+		retval = access_remote_vm(mm, (env_start + src), page, this_len, FOLL_ANON);
+
+		if (retval <= 0) {
+			ret = retval;
+			break;
+		}
+
+		if (copy_to_user(buf, page, retval)) {
+			ret = -EFAULT;
+			break;
+		}
+
+		ret += retval;
+		src += retval;
+		buf += retval;
+		count -= retval;
+	}
+	*ppos = src;
+	mmput(mm);
+
+free:
+	free_page((unsigned long) page);
+	return ret;
+}
+
+static const struct file_operations proc_environ_operations = {
+	.open		= environ_open,
+	.read		= environ_read,
+	.llseek		= generic_file_llseek,
+	.release	= mem_release,
+};
+
+static int auxv_open(struct inode *inode, struct file *file)
+{
+	return __mem_open(inode, file, PTRACE_MODE_READ_FSCREDS);
+}
+
+static ssize_t auxv_read(struct file *file, char __user *buf,
+			size_t count, loff_t *ppos)
+{
+	struct mm_struct *mm = file->private_data;
+	unsigned int nwords = 0;
+
+	if (!mm)
+		return 0;
+	do {
+		nwords += 2;
+	} while (mm->saved_auxv[nwords - 2] != 0); /* AT_NULL */
+	return simple_read_from_buffer(buf, count, ppos, mm->saved_auxv,
+				       nwords * sizeof(mm->saved_auxv[0]));
+}
+
+static const struct file_operations proc_auxv_operations = {
+	.open		= auxv_open,
+	.read		= auxv_read,
+	.llseek		= generic_file_llseek,
+	.release	= mem_release,
+};
+
+static ssize_t oom_adj_read(struct file *file, char __user *buf, size_t count,
+			    loff_t *ppos)
+{
+	struct task_struct *task = get_proc_task(file_inode(file));
+	char buffer[PROC_NUMBUF];
+	int oom_adj = OOM_ADJUST_MIN;
+	size_t len;
+
+	if (!task)
+		return -ESRCH;
+	if (task->signal->oom_score_adj == OOM_SCORE_ADJ_MAX)
+		oom_adj = OOM_ADJUST_MAX;
+	else
+		oom_adj = (task->signal->oom_score_adj * -OOM_DISABLE) /
+			  OOM_SCORE_ADJ_MAX;
+	put_task_struct(task);
+	if (oom_adj > OOM_ADJUST_MAX)
+		oom_adj = OOM_ADJUST_MAX;
+	len = snprintf(buffer, sizeof(buffer), "%d\n", oom_adj);
+	return simple_read_from_buffer(buf, count, ppos, buffer, len);
+}
+
+static int __set_oom_adj(struct file *file, int oom_adj, bool legacy)
+{
+	struct mm_struct *mm = NULL;
+	struct task_struct *task;
+	int err = 0;
+
+	task = get_proc_task(file_inode(file));
+	if (!task)
+		return -ESRCH;
+
+	mutex_lock(&oom_adj_mutex);
+	if (legacy) {
+		if (oom_adj < task->signal->oom_score_adj &&
+				!capable(CAP_SYS_RESOURCE)) {
+			err = -EACCES;
+			goto err_unlock;
+		}
+		/*
+		 * /proc/pid/oom_adj is provided for legacy purposes, ask users to use
+		 * /proc/pid/oom_score_adj instead.
+		 */
+		pr_warn_once("%s (%d): /proc/%d/oom_adj is deprecated, please use /proc/%d/oom_score_adj instead.\n",
+			  current->comm, task_pid_nr(current), task_pid_nr(task),
+			  task_pid_nr(task));
+	} else {
+		if ((short)oom_adj < task->signal->oom_score_adj_min &&
+				!capable(CAP_SYS_RESOURCE)) {
+			err = -EACCES;
+			goto err_unlock;
+		}
+	}
+
+	/*
+	 * Make sure we will check other processes sharing the mm if this is
+	 * not vfrok which wants its own oom_score_adj.
+	 * pin the mm so it doesn't go away and get reused after task_unlock
+	 */
+	if (!task->vfork_done) {
+		struct task_struct *p = find_lock_task_mm(task);
+
+		if (p) {
+			if (test_bit(MMF_MULTIPROCESS, &p->mm->flags)) {
+				mm = p->mm;
+				mmgrab(mm);
+			}
+			task_unlock(p);
+		}
+	}
+
+	task->signal->oom_score_adj = oom_adj;
+	if (!legacy && has_capability_noaudit(current, CAP_SYS_RESOURCE))
+		task->signal->oom_score_adj_min = (short)oom_adj;
+	trace_oom_score_adj_update(task);
+
+	if (mm) {
+		struct task_struct *p;
+
+		rcu_read_lock();
+		for_each_process(p) {
+			if (same_thread_group(task, p))
+				continue;
+
+			/* do not touch kernel threads or the global init */
+			if (p->flags & PF_KTHREAD || is_global_init(p))
+				continue;
+
+			task_lock(p);
+			if (!p->vfork_done && process_shares_mm(p, mm)) {
+				p->signal->oom_score_adj = oom_adj;
+				if (!legacy && has_capability_noaudit(current, CAP_SYS_RESOURCE))
+					p->signal->oom_score_adj_min = (short)oom_adj;
+			}
+			task_unlock(p);
+		}
+		rcu_read_unlock();
+		mmdrop(mm);
+	}
+err_unlock:
+	mutex_unlock(&oom_adj_mutex);
+	put_task_struct(task);
+	return err;
+}
+
+/*
+ * /proc/pid/oom_adj exists solely for backwards compatibility with previous
+ * kernels.  The effective policy is defined by oom_score_adj, which has a
+ * different scale: oom_adj grew exponentially and oom_score_adj grows linearly.
+ * Values written to oom_adj are simply mapped linearly to oom_score_adj.
+ * Processes that become oom disabled via oom_adj will still be oom disabled
+ * with this implementation.
+ *
+ * oom_adj cannot be removed since existing userspace binaries use it.
+ */
+static ssize_t oom_adj_write(struct file *file, const char __user *buf,
+			     size_t count, loff_t *ppos)
+{
+	char buffer[PROC_NUMBUF];
+	int oom_adj;
+	int err;
+
+	memset(buffer, 0, sizeof(buffer));
+	if (count > sizeof(buffer) - 1)
+		count = sizeof(buffer) - 1;
+	if (copy_from_user(buffer, buf, count)) {
+		err = -EFAULT;
+		goto out;
+	}
+
+	err = kstrtoint(strstrip(buffer), 0, &oom_adj);
+	if (err)
+		goto out;
+	if ((oom_adj < OOM_ADJUST_MIN || oom_adj > OOM_ADJUST_MAX) &&
+	     oom_adj != OOM_DISABLE) {
+		err = -EINVAL;
+		goto out;
+	}
+
+	/*
+	 * Scale /proc/pid/oom_score_adj appropriately ensuring that a maximum
+	 * value is always attainable.
+	 */
+	if (oom_adj == OOM_ADJUST_MAX)
+		oom_adj = OOM_SCORE_ADJ_MAX;
+	else
+		oom_adj = (oom_adj * OOM_SCORE_ADJ_MAX) / -OOM_DISABLE;
+
+	err = __set_oom_adj(file, oom_adj, true);
+out:
+	return err < 0 ? err : count;
+}
+
+static const struct file_operations proc_oom_adj_operations = {
+	.read		= oom_adj_read,
+	.write		= oom_adj_write,
+	.llseek		= generic_file_llseek,
+};
+
+static ssize_t oom_score_adj_read(struct file *file, char __user *buf,
+					size_t count, loff_t *ppos)
+{
+	struct task_struct *task = get_proc_task(file_inode(file));
+	char buffer[PROC_NUMBUF];
+	short oom_score_adj = OOM_SCORE_ADJ_MIN;
+	size_t len;
+
+	if (!task)
+		return -ESRCH;
+	oom_score_adj = task->signal->oom_score_adj;
+	put_task_struct(task);
+	len = snprintf(buffer, sizeof(buffer), "%hd\n", oom_score_adj);
+	return simple_read_from_buffer(buf, count, ppos, buffer, len);
+}
+
+static ssize_t oom_score_adj_write(struct file *file, const char __user *buf,
+					size_t count, loff_t *ppos)
+{
+	char buffer[PROC_NUMBUF];
+	int oom_score_adj;
+	int err;
+
+	memset(buffer, 0, sizeof(buffer));
+	if (count > sizeof(buffer) - 1)
+		count = sizeof(buffer) - 1;
+	if (copy_from_user(buffer, buf, count)) {
+		err = -EFAULT;
+		goto out;
+	}
+
+	err = kstrtoint(strstrip(buffer), 0, &oom_score_adj);
+	if (err)
+		goto out;
+	if (oom_score_adj < OOM_SCORE_ADJ_MIN ||
+			oom_score_adj > OOM_SCORE_ADJ_MAX) {
+		err = -EINVAL;
+		goto out;
+	}
+
+	err = __set_oom_adj(file, oom_score_adj, false);
+out:
+	return err < 0 ? err : count;
+}
+
+static const struct file_operations proc_oom_score_adj_operations = {
+	.read		= oom_score_adj_read,
+	.write		= oom_score_adj_write,
+	.llseek		= default_llseek,
+};
+
+#ifdef CONFIG_AUDIT
+#define TMPBUFLEN 11
+static ssize_t proc_loginuid_read(struct file * file, char __user * buf,
+				  size_t count, loff_t *ppos)
+{
+	struct inode * inode = file_inode(file);
+	struct task_struct *task = get_proc_task(inode);
+	ssize_t length;
+	char tmpbuf[TMPBUFLEN];
+
+	if (!task)
+		return -ESRCH;
+	length = scnprintf(tmpbuf, TMPBUFLEN, "%u",
+			   from_kuid(file->f_cred->user_ns,
+				     audit_get_loginuid(task)));
+	put_task_struct(task);
+	return simple_read_from_buffer(buf, count, ppos, tmpbuf, length);
+}
+
+static ssize_t proc_loginuid_write(struct file * file, const char __user * buf,
+				   size_t count, loff_t *ppos)
+{
+	struct inode * inode = file_inode(file);
+	uid_t loginuid;
+	kuid_t kloginuid;
+	int rv;
+
+	/* Don't let kthreads write their own loginuid */
+	if (current->flags & PF_KTHREAD)
+		return -EPERM;
+
+	rcu_read_lock();
+	if (current != pid_task(proc_pid(inode), PIDTYPE_PID)) {
+		rcu_read_unlock();
+		return -EPERM;
+	}
+	rcu_read_unlock();
+
+	if (*ppos != 0) {
+		/* No partial writes. */
+		return -EINVAL;
+	}
+
+	rv = kstrtou32_from_user(buf, count, 10, &loginuid);
+	if (rv < 0)
+		return rv;
+
+	/* is userspace tring to explicitly UNSET the loginuid? */
+	if (loginuid == AUDIT_UID_UNSET) {
+		kloginuid = INVALID_UID;
+	} else {
+		kloginuid = make_kuid(file->f_cred->user_ns, loginuid);
+		if (!uid_valid(kloginuid))
+			return -EINVAL;
+	}
+
+	rv = audit_set_loginuid(kloginuid);
+	if (rv < 0)
+		return rv;
+	return count;
+}
+
+static const struct file_operations proc_loginuid_operations = {
+	.read		= proc_loginuid_read,
+	.write		= proc_loginuid_write,
+	.llseek		= generic_file_llseek,
+};
+
+static ssize_t proc_sessionid_read(struct file * file, char __user * buf,
+				  size_t count, loff_t *ppos)
+{
+	struct inode * inode = file_inode(file);
+	struct task_struct *task = get_proc_task(inode);
+	ssize_t length;
+	char tmpbuf[TMPBUFLEN];
+
+	if (!task)
+		return -ESRCH;
+	length = scnprintf(tmpbuf, TMPBUFLEN, "%u",
+				audit_get_sessionid(task));
+	put_task_struct(task);
+	return simple_read_from_buffer(buf, count, ppos, tmpbuf, length);
+}
+
+static const struct file_operations proc_sessionid_operations = {
+	.read		= proc_sessionid_read,
+	.llseek		= generic_file_llseek,
+};
+#endif
+
+#ifdef CONFIG_FAULT_INJECTION
+static ssize_t proc_fault_inject_read(struct file * file, char __user * buf,
+				      size_t count, loff_t *ppos)
+{
+	struct task_struct *task = get_proc_task(file_inode(file));
+	char buffer[PROC_NUMBUF];
+	size_t len;
+	int make_it_fail;
+
+	if (!task)
+		return -ESRCH;
+	make_it_fail = task->make_it_fail;
+	put_task_struct(task);
+
+	len = snprintf(buffer, sizeof(buffer), "%i\n", make_it_fail);
+
+	return simple_read_from_buffer(buf, count, ppos, buffer, len);
+}
+
+static ssize_t proc_fault_inject_write(struct file * file,
+			const char __user * buf, size_t count, loff_t *ppos)
+{
+	struct task_struct *task;
+	char buffer[PROC_NUMBUF];
+	int make_it_fail;
+	int rv;
+
+	if (!capable(CAP_SYS_RESOURCE))
+		return -EPERM;
+	memset(buffer, 0, sizeof(buffer));
+	if (count > sizeof(buffer) - 1)
+		count = sizeof(buffer) - 1;
+	if (copy_from_user(buffer, buf, count))
+		return -EFAULT;
+	rv = kstrtoint(strstrip(buffer), 0, &make_it_fail);
+	if (rv < 0)
+		return rv;
+	if (make_it_fail < 0 || make_it_fail > 1)
+		return -EINVAL;
+
+	task = get_proc_task(file_inode(file));
+	if (!task)
+		return -ESRCH;
+	task->make_it_fail = make_it_fail;
+	put_task_struct(task);
+
+	return count;
+}
+
+static const struct file_operations proc_fault_inject_operations = {
+	.read		= proc_fault_inject_read,
+	.write		= proc_fault_inject_write,
+	.llseek		= generic_file_llseek,
+};
+
+static ssize_t proc_fail_nth_write(struct file *file, const char __user *buf,
+				   size_t count, loff_t *ppos)
+{
+	struct task_struct *task;
+	int err;
+	unsigned int n;
+
+	err = kstrtouint_from_user(buf, count, 0, &n);
+	if (err)
+		return err;
+
+	task = get_proc_task(file_inode(file));
+	if (!task)
+		return -ESRCH;
+	task->fail_nth = n;
+	put_task_struct(task);
+
+	return count;
+}
+
+static ssize_t proc_fail_nth_read(struct file *file, char __user *buf,
+				  size_t count, loff_t *ppos)
+{
+	struct task_struct *task;
+	char numbuf[PROC_NUMBUF];
+	ssize_t len;
+
+	task = get_proc_task(file_inode(file));
+	if (!task)
+		return -ESRCH;
+	len = snprintf(numbuf, sizeof(numbuf), "%u\n", task->fail_nth);
+	put_task_struct(task);
+	return simple_read_from_buffer(buf, count, ppos, numbuf, len);
+}
+
+static const struct file_operations proc_fail_nth_operations = {
+	.read		= proc_fail_nth_read,
+	.write		= proc_fail_nth_write,
+};
+#endif
+
+
+#ifdef CONFIG_SCHED_DEBUG
+/*
+ * Print out various scheduling related per-task fields:
+ */
+static int sched_show(struct seq_file *m, void *v)
+{
+	struct inode *inode = m->private;
+	struct pid_namespace *ns = proc_pid_ns(inode->i_sb);
+	struct task_struct *p;
+
+	p = get_proc_task(inode);
+	if (!p)
+		return -ESRCH;
+	proc_sched_show_task(p, ns, m);
+
+	put_task_struct(p);
+
+	return 0;
+}
+
+static ssize_t
+sched_write(struct file *file, const char __user *buf,
+	    size_t count, loff_t *offset)
+{
+	struct inode *inode = file_inode(file);
+	struct task_struct *p;
+
+	p = get_proc_task(inode);
+	if (!p)
+		return -ESRCH;
+	proc_sched_set_task(p);
+
+	put_task_struct(p);
+
+	return count;
+}
+
+static int sched_open(struct inode *inode, struct file *filp)
+{
+	return single_open(filp, sched_show, inode);
+}
+
+static const struct file_operations proc_pid_sched_operations = {
+	.open		= sched_open,
+	.read		= seq_read,
+	.write		= sched_write,
+	.llseek		= seq_lseek,
+	.release	= single_release,
+};
+
+#endif
+
+#ifdef CONFIG_SCHED_AUTOGROUP
+/*
+ * Print out autogroup related information:
+ */
+static int sched_autogroup_show(struct seq_file *m, void *v)
+{
+	struct inode *inode = m->private;
+	struct task_struct *p;
+
+	p = get_proc_task(inode);
+	if (!p)
+		return -ESRCH;
+	proc_sched_autogroup_show_task(p, m);
+
+	put_task_struct(p);
+
+	return 0;
+}
+
+static ssize_t
+sched_autogroup_write(struct file *file, const char __user *buf,
+	    size_t count, loff_t *offset)
+{
+	struct inode *inode = file_inode(file);
+	struct task_struct *p;
+	char buffer[PROC_NUMBUF];
+	int nice;
+	int err;
+
+	memset(buffer, 0, sizeof(buffer));
+	if (count > sizeof(buffer) - 1)
+		count = sizeof(buffer) - 1;
+	if (copy_from_user(buffer, buf, count))
+		return -EFAULT;
+
+	err = kstrtoint(strstrip(buffer), 0, &nice);
+	if (err < 0)
+		return err;
+
+	p = get_proc_task(inode);
+	if (!p)
+		return -ESRCH;
+
+	err = proc_sched_autogroup_set_nice(p, nice);
+	if (err)
+		count = err;
+
+	put_task_struct(p);
+
+	return count;
+}
+
+static int sched_autogroup_open(struct inode *inode, struct file *filp)
+{
+	int ret;
+
+	ret = single_open(filp, sched_autogroup_show, NULL);
+	if (!ret) {
+		struct seq_file *m = filp->private_data;
+
+		m->private = inode;
+	}
+	return ret;
+}
+
+static const struct file_operations proc_pid_sched_autogroup_operations = {
+	.open		= sched_autogroup_open,
+	.read		= seq_read,
+	.write		= sched_autogroup_write,
+	.llseek		= seq_lseek,
+	.release	= single_release,
+};
+
+#endif /* CONFIG_SCHED_AUTOGROUP */
+
+#ifdef CONFIG_TIME_NS
+static int timens_offsets_show(struct seq_file *m, void *v)
+{
+	struct task_struct *p;
+
+	p = get_proc_task(file_inode(m->file));
+	if (!p)
+		return -ESRCH;
+	proc_timens_show_offsets(p, m);
+
+	put_task_struct(p);
+
+	return 0;
+}
+
+static ssize_t timens_offsets_write(struct file *file, const char __user *buf,
+				    size_t count, loff_t *ppos)
+{
+	struct inode *inode = file_inode(file);
+	struct proc_timens_offset offsets[2];
+	char *kbuf = NULL, *pos, *next_line;
+	struct task_struct *p;
+	int ret, noffsets;
+
+	/* Only allow < page size writes at the beginning of the file */
+	if ((*ppos != 0) || (count >= PAGE_SIZE))
+		return -EINVAL;
+
+	/* Slurp in the user data */
+	kbuf = memdup_user_nul(buf, count);
+	if (IS_ERR(kbuf))
+		return PTR_ERR(kbuf);
+
+	/* Parse the user data */
+	ret = -EINVAL;
+	noffsets = 0;
+	for (pos = kbuf; pos; pos = next_line) {
+		struct proc_timens_offset *off = &offsets[noffsets];
+		char clock[10];
+		int err;
+
+		/* Find the end of line and ensure we don't look past it */
+		next_line = strchr(pos, '\n');
+		if (next_line) {
+			*next_line = '\0';
+			next_line++;
+			if (*next_line == '\0')
+				next_line = NULL;
+		}
+
+		err = sscanf(pos, "%9s %lld %lu", clock,
+				&off->val.tv_sec, &off->val.tv_nsec);
+		if (err != 3 || off->val.tv_nsec >= NSEC_PER_SEC)
+			goto out;
+
+		clock[sizeof(clock) - 1] = 0;
+		if (strcmp(clock, "monotonic") == 0 ||
+		    strcmp(clock, __stringify(CLOCK_MONOTONIC)) == 0)
+			off->clockid = CLOCK_MONOTONIC;
+		else if (strcmp(clock, "boottime") == 0 ||
+			 strcmp(clock, __stringify(CLOCK_BOOTTIME)) == 0)
+			off->clockid = CLOCK_BOOTTIME;
+		else
+			goto out;
+
+		noffsets++;
+		if (noffsets == ARRAY_SIZE(offsets)) {
+			if (next_line)
+				count = next_line - kbuf;
+			break;
+		}
+	}
+
+	ret = -ESRCH;
+	p = get_proc_task(inode);
+	if (!p)
+		goto out;
+	ret = proc_timens_set_offset(file, p, offsets, noffsets);
+	put_task_struct(p);
+	if (ret)
+		goto out;
+
+	ret = count;
+out:
+	kfree(kbuf);
+	return ret;
+}
+
+static int timens_offsets_open(struct inode *inode, struct file *filp)
+{
+	return single_open(filp, timens_offsets_show, inode);
+}
+
+static const struct file_operations proc_timens_offsets_operations = {
+	.open		= timens_offsets_open,
+	.read		= seq_read,
+	.write		= timens_offsets_write,
+	.llseek		= seq_lseek,
+	.release	= single_release,
+};
+#endif /* CONFIG_TIME_NS */
+
+static ssize_t comm_write(struct file *file, const char __user *buf,
+				size_t count, loff_t *offset)
+{
+	struct inode *inode = file_inode(file);
+	struct task_struct *p;
+	char buffer[TASK_COMM_LEN];
+	const size_t maxlen = sizeof(buffer) - 1;
+
+	memset(buffer, 0, sizeof(buffer));
+	if (copy_from_user(buffer, buf, count > maxlen ? maxlen : count))
+		return -EFAULT;
+
+	p = get_proc_task(inode);
+	if (!p)
+		return -ESRCH;
+
+	if (same_thread_group(current, p)) {
+		set_task_comm(p, buffer);
+		proc_comm_connector(p);
+	}
+	else
+		count = -EINVAL;
+
+	put_task_struct(p);
+
+	return count;
+}
+
+static int comm_show(struct seq_file *m, void *v)
+{
+	struct inode *inode = m->private;
+	struct task_struct *p;
+
+	p = get_proc_task(inode);
+	if (!p)
+		return -ESRCH;
+
+	proc_task_name(m, p, false);
+	seq_putc(m, '\n');
+
+	put_task_struct(p);
+
+	return 0;
+}
+
+static int comm_open(struct inode *inode, struct file *filp)
+{
+	return single_open(filp, comm_show, inode);
+}
+
+static const struct file_operations proc_pid_set_comm_operations = {
+	.open		= comm_open,
+	.read		= seq_read,
+	.write		= comm_write,
+	.llseek		= seq_lseek,
+	.release	= single_release,
+};
+
+static int proc_exe_link(struct dentry *dentry, struct path *exe_path)
+{
+	struct task_struct *task;
+	struct file *exe_file;
+
+	task = get_proc_task(d_inode(dentry));
+	if (!task)
+		return -ENOENT;
+	exe_file = get_task_exe_file(task);
+	put_task_struct(task);
+	if (exe_file) {
+		*exe_path = exe_file->f_path;
+		path_get(&exe_file->f_path);
+		fput(exe_file);
+		return 0;
+	} else
+		return -ENOENT;
+}
+
+static const char *proc_pid_get_link(struct dentry *dentry,
+				     struct inode *inode,
+				     struct delayed_call *done)
+{
+	struct path path;
+	int error = -EACCES;
+
+	if (!dentry)
+		return ERR_PTR(-ECHILD);
+
+	/* Are we allowed to snoop on the tasks file descriptors? */
+	if (!proc_fd_access_allowed(inode))
+		goto out;
+
+	error = PROC_I(inode)->op.proc_get_link(dentry, &path);
+	if (error)
+		goto out;
+
+	error = nd_jump_link(&path);
+out:
+	return ERR_PTR(error);
+}
+
+static int do_proc_readlink(const struct path *path, char __user *buffer, int buflen)
+{
+	char *tmp = kmalloc(PATH_MAX, GFP_KERNEL);
+	char *pathname;
+	int len;
+
+	if (!tmp)
+		return -ENOMEM;
+
+	pathname = d_path(path, tmp, PATH_MAX);
+	len = PTR_ERR(pathname);
+	if (IS_ERR(pathname))
+		goto out;
+	len = tmp + PATH_MAX - 1 - pathname;
+
+	if (len > buflen)
+		len = buflen;
+	if (copy_to_user(buffer, pathname, len))
+		len = -EFAULT;
+ out:
+	kfree(tmp);
+	return len;
+}
+
+static int proc_pid_readlink(struct dentry * dentry, char __user * buffer, int buflen)
+{
+	int error = -EACCES;
+	struct inode *inode = d_inode(dentry);
+	struct path path;
+
+	/* Are we allowed to snoop on the tasks file descriptors? */
+	if (!proc_fd_access_allowed(inode))
+		goto out;
+
+	error = PROC_I(inode)->op.proc_get_link(dentry, &path);
+	if (error)
+		goto out;
+
+	error = do_proc_readlink(&path, buffer, buflen);
+	path_put(&path);
+out:
+	return error;
+}
+
+const struct inode_operations proc_pid_link_inode_operations = {
+	.readlink	= proc_pid_readlink,
+	.get_link	= proc_pid_get_link,
+	.setattr	= proc_setattr,
+};
+
+
+/* building an inode */
+
+void task_dump_owner(struct task_struct *task, umode_t mode,
+		     kuid_t *ruid, kgid_t *rgid)
+{
+	/* Depending on the state of dumpable compute who should own a
+	 * proc file for a task.
+	 */
+	const struct cred *cred;
+	kuid_t uid;
+	kgid_t gid;
+
+	if (unlikely(task->flags & PF_KTHREAD)) {
+		*ruid = GLOBAL_ROOT_UID;
+		*rgid = GLOBAL_ROOT_GID;
+		return;
+	}
+
+	/* Default to the tasks effective ownership */
+	rcu_read_lock();
+	cred = __task_cred(task);
+	uid = cred->euid;
+	gid = cred->egid;
+	rcu_read_unlock();
+
+	/*
+	 * Before the /proc/pid/status file was created the only way to read
+	 * the effective uid of a /process was to stat /proc/pid.  Reading
+	 * /proc/pid/status is slow enough that procps and other packages
+	 * kept stating /proc/pid.  To keep the rules in /proc simple I have
+	 * made this apply to all per process world readable and executable
+	 * directories.
+	 */
+	if (mode != (S_IFDIR|S_IRUGO|S_IXUGO)) {
+		struct mm_struct *mm;
+		task_lock(task);
+		mm = task->mm;
+		/* Make non-dumpable tasks owned by some root */
+		if (mm) {
+			if (get_dumpable(mm) != SUID_DUMP_USER) {
+				struct user_namespace *user_ns = mm->user_ns;
+
+				uid = make_kuid(user_ns, 0);
+				if (!uid_valid(uid))
+					uid = GLOBAL_ROOT_UID;
+
+				gid = make_kgid(user_ns, 0);
+				if (!gid_valid(gid))
+					gid = GLOBAL_ROOT_GID;
+			}
+		} else {
+			uid = GLOBAL_ROOT_UID;
+			gid = GLOBAL_ROOT_GID;
+		}
+		task_unlock(task);
+	}
+	*ruid = uid;
+	*rgid = gid;
+}
+
+void proc_pid_evict_inode(struct proc_inode *ei)
+{
+	struct pid *pid = ei->pid;
+
+	if (S_ISDIR(ei->vfs_inode.i_mode)) {
+		spin_lock(&pid->lock);
+		hlist_del_init_rcu(&ei->sibling_inodes);
+		spin_unlock(&pid->lock);
+	}
+
+	put_pid(pid);
+}
+
+struct inode *proc_pid_make_inode(struct super_block *sb,
+				  struct task_struct *task, umode_t mode)
+{
+	struct inode * inode;
+	struct proc_inode *ei;
+	struct pid *pid;
+
+	/* We need a new inode */
+
+	inode = new_inode(sb);
+	if (!inode)
+		goto out;
+
+	/* Common stuff */
+	ei = PROC_I(inode);
+	inode->i_mode = mode;
+	inode->i_ino = get_next_ino();
+	inode->i_mtime = inode->i_atime = inode->i_ctime = current_time(inode);
+	inode->i_op = &proc_def_inode_operations;
+
+	/*
+	 * grab the reference to task.
+	 */
+	pid = get_task_pid(task, PIDTYPE_PID);
+	if (!pid)
+		goto out_unlock;
+
+	/* Let the pid remember us for quick removal */
+	ei->pid = pid;
+
+	task_dump_owner(task, 0, &inode->i_uid, &inode->i_gid);
+	security_task_to_inode(task, inode);
+
+out:
+	return inode;
+
+out_unlock:
+	iput(inode);
+	return NULL;
+}
+
+/*
+ * Generating an inode and adding it into @pid->inodes, so that task will
+ * invalidate inode's dentry before being released.
+ *
+ * This helper is used for creating dir-type entries under '/proc' and
+ * '/proc/<tgid>/task'. Other entries(eg. fd, stat) under '/proc/<tgid>'
+ * can be released by invalidating '/proc/<tgid>' dentry.
+ * In theory, dentries under '/proc/<tgid>/task' can also be released by
+ * invalidating '/proc/<tgid>' dentry, we reserve it to handle single
+ * thread exiting situation: Any one of threads should invalidate its
+ * '/proc/<tgid>/task/<pid>' dentry before released.
+ */
+static struct inode *proc_pid_make_base_inode(struct super_block *sb,
+				struct task_struct *task, umode_t mode)
+{
+	struct inode *inode;
+	struct proc_inode *ei;
+	struct pid *pid;
+
+	inode = proc_pid_make_inode(sb, task, mode);
+	if (!inode)
+		return NULL;
+
+	/* Let proc_flush_pid find this directory inode */
+	ei = PROC_I(inode);
+	pid = ei->pid;
+	spin_lock(&pid->lock);
+	hlist_add_head_rcu(&ei->sibling_inodes, &pid->inodes);
+	spin_unlock(&pid->lock);
+
+	return inode;
+}
+
+int pid_getattr(struct user_namespace *mnt_userns, const struct path *path,
+		struct kstat *stat, u32 request_mask, unsigned int query_flags)
+{
+	struct inode *inode = d_inode(path->dentry);
+	struct proc_fs_info *fs_info = proc_sb_info(inode->i_sb);
+	struct task_struct *task;
+
+	generic_fillattr(&init_user_ns, inode, stat);
+
+	stat->uid = GLOBAL_ROOT_UID;
+	stat->gid = GLOBAL_ROOT_GID;
+	rcu_read_lock();
+	task = pid_task(proc_pid(inode), PIDTYPE_PID);
+	if (task) {
+		if (!has_pid_permissions(fs_info, task, HIDEPID_INVISIBLE)) {
+			rcu_read_unlock();
+			/*
+			 * This doesn't prevent learning whether PID exists,
+			 * it only makes getattr() consistent with readdir().
+			 */
+			return -ENOENT;
+		}
+		task_dump_owner(task, inode->i_mode, &stat->uid, &stat->gid);
+	}
+	rcu_read_unlock();
+	return 0;
+}
+
+/* dentry stuff */
+
+/*
+ * Set <pid>/... inode ownership (can change due to setuid(), etc.)
+ */
+void pid_update_inode(struct task_struct *task, struct inode *inode)
+{
+	task_dump_owner(task, inode->i_mode, &inode->i_uid, &inode->i_gid);
+
+	inode->i_mode &= ~(S_ISUID | S_ISGID);
+	security_task_to_inode(task, inode);
+}
+
+/*
+ * Rewrite the inode's ownerships here because the owning task may have
+ * performed a setuid(), etc.
+ *
+ */
+static int pid_revalidate(struct dentry *dentry, unsigned int flags)
+{
+	struct inode *inode;
+	struct task_struct *task;
+	int ret = 0;
+
+	rcu_read_lock();
+	inode = d_inode_rcu(dentry);
+	if (!inode)
+		goto out;
+	task = pid_task(proc_pid(inode), PIDTYPE_PID);
+
+	if (task) {
+		pid_update_inode(task, inode);
+		ret = 1;
+	}
+out:
+	rcu_read_unlock();
+	return ret;
+}
+
+static inline bool proc_inode_is_dead(struct inode *inode)
+{
+	return !proc_pid(inode)->tasks[PIDTYPE_PID].first;
+}
+
+int pid_delete_dentry(const struct dentry *dentry)
+{
+	/* Is the task we represent dead?
+	 * If so, then don't put the dentry on the lru list,
+	 * kill it immediately.
+	 */
+	return proc_inode_is_dead(d_inode(dentry));
+}
+
+const struct dentry_operations pid_dentry_operations =
+{
+	.d_revalidate	= pid_revalidate,
+	.d_delete	= pid_delete_dentry,
+};
+
+/* Lookups */
+
+/*
+ * Fill a directory entry.
+ *
+ * If possible create the dcache entry and derive our inode number and
+ * file type from dcache entry.
+ *
+ * Since all of the proc inode numbers are dynamically generated, the inode
+ * numbers do not exist until the inode is cache.  This means creating
+ * the dcache entry in readdir is necessary to keep the inode numbers
+ * reported by readdir in sync with the inode numbers reported
+ * by stat.
+ */
+bool proc_fill_cache(struct file *file, struct dir_context *ctx,
+	const char *name, unsigned int len,
+	instantiate_t instantiate, struct task_struct *task, const void *ptr)
+{
+	struct dentry *child, *dir = file->f_path.dentry;
+	struct qstr qname = QSTR_INIT(name, len);
+	struct inode *inode;
+	unsigned type = DT_UNKNOWN;
+	ino_t ino = 1;
+
+	child = d_hash_and_lookup(dir, &qname);
+	if (!child) {
+		DECLARE_WAIT_QUEUE_HEAD_ONSTACK(wq);
+		child = d_alloc_parallel(dir, &qname, &wq);
+		if (IS_ERR(child))
+			goto end_instantiate;
+		if (d_in_lookup(child)) {
+			struct dentry *res;
+			res = instantiate(child, task, ptr);
+			d_lookup_done(child);
+			if (unlikely(res)) {
+				dput(child);
+				child = res;
+				if (IS_ERR(child))
+					goto end_instantiate;
+			}
+		}
+	}
+	inode = d_inode(child);
+	ino = inode->i_ino;
+	type = inode->i_mode >> 12;
+	dput(child);
+end_instantiate:
+	return dir_emit(ctx, name, len, ino, type);
+}
+
+/*
+ * dname_to_vma_addr - maps a dentry name into two unsigned longs
+ * which represent vma start and end addresses.
+ */
+static int dname_to_vma_addr(struct dentry *dentry,
+			     unsigned long *start, unsigned long *end)
+{
+	const char *str = dentry->d_name.name;
+	unsigned long long sval, eval;
+	unsigned int len;
+
+	if (str[0] == '0' && str[1] != '-')
+		return -EINVAL;
+	len = _parse_integer(str, 16, &sval);
+	if (len & KSTRTOX_OVERFLOW)
+		return -EINVAL;
+	if (sval != (unsigned long)sval)
+		return -EINVAL;
+	str += len;
+
+	if (*str != '-')
+		return -EINVAL;
+	str++;
+
+	if (str[0] == '0' && str[1])
+		return -EINVAL;
+	len = _parse_integer(str, 16, &eval);
+	if (len & KSTRTOX_OVERFLOW)
+		return -EINVAL;
+	if (eval != (unsigned long)eval)
+		return -EINVAL;
+	str += len;
+
+	if (*str != '\0')
+		return -EINVAL;
+
+	*start = sval;
+	*end = eval;
+
+	return 0;
+}
+
+static int map_files_d_revalidate(struct dentry *dentry, unsigned int flags)
+{
+	unsigned long vm_start, vm_end;
+	bool exact_vma_exists = false;
+	struct mm_struct *mm = NULL;
+	struct task_struct *task;
+	struct inode *inode;
+	int status = 0;
+
+	if (flags & LOOKUP_RCU)
+		return -ECHILD;
+
+	inode = d_inode(dentry);
+	task = get_proc_task(inode);
+	if (!task)
+		goto out_notask;
+
+	mm = mm_access(task, PTRACE_MODE_READ_FSCREDS);
+	if (IS_ERR_OR_NULL(mm))
+		goto out;
+
+	if (!dname_to_vma_addr(dentry, &vm_start, &vm_end)) {
+		status = mmap_read_lock_killable(mm);
+		if (!status) {
+			exact_vma_exists = !!find_exact_vma(mm, vm_start,
+							    vm_end);
+			mmap_read_unlock(mm);
+		}
+	}
+
+	mmput(mm);
+
+	if (exact_vma_exists) {
+		task_dump_owner(task, 0, &inode->i_uid, &inode->i_gid);
+
+		security_task_to_inode(task, inode);
+		status = 1;
+	}
+
+out:
+	put_task_struct(task);
+
+out_notask:
+	return status;
+}
+
+static const struct dentry_operations tid_map_files_dentry_operations = {
+	.d_revalidate	= map_files_d_revalidate,
+	.d_delete	= pid_delete_dentry,
+};
+
+static int map_files_get_link(struct dentry *dentry, struct path *path)
+{
+	unsigned long vm_start, vm_end;
+	struct vm_area_struct *vma;
+	struct task_struct *task;
+	struct mm_struct *mm;
+	int rc;
+
+	rc = -ENOENT;
+	task = get_proc_task(d_inode(dentry));
+	if (!task)
+		goto out;
+
+	mm = get_task_mm(task);
+	put_task_struct(task);
+	if (!mm)
+		goto out;
+
+	rc = dname_to_vma_addr(dentry, &vm_start, &vm_end);
+	if (rc)
+		goto out_mmput;
+
+	rc = mmap_read_lock_killable(mm);
+	if (rc)
+		goto out_mmput;
+
+	rc = -ENOENT;
+	vma = find_exact_vma(mm, vm_start, vm_end);
+	if (vma && vma->vm_file) {
+		*path = vma->vm_file->f_path;
+		path_get(path);
+		rc = 0;
+	}
+	mmap_read_unlock(mm);
+
+out_mmput:
+	mmput(mm);
+out:
+	return rc;
+}
+
+struct map_files_info {
+	unsigned long	start;
+	unsigned long	end;
+	fmode_t		mode;
+};
+
+/*
+ * Only allow CAP_SYS_ADMIN and CAP_CHECKPOINT_RESTORE to follow the links, due
+ * to concerns about how the symlinks may be used to bypass permissions on
+ * ancestor directories in the path to the file in question.
+ */
+static const char *
+proc_map_files_get_link(struct dentry *dentry,
+			struct inode *inode,
+		        struct delayed_call *done)
+{
+	if (!checkpoint_restore_ns_capable(&init_user_ns))
+		return ERR_PTR(-EPERM);
+
+	return proc_pid_get_link(dentry, inode, done);
+}
+
+/*
+ * Identical to proc_pid_link_inode_operations except for get_link()
+ */
+static const struct inode_operations proc_map_files_link_inode_operations = {
+	.readlink	= proc_pid_readlink,
+	.get_link	= proc_map_files_get_link,
+	.setattr	= proc_setattr,
+};
+
+static struct dentry *
+proc_map_files_instantiate(struct dentry *dentry,
+			   struct task_struct *task, const void *ptr)
+{
+	fmode_t mode = (fmode_t)(unsigned long)ptr;
+	struct proc_inode *ei;
+	struct inode *inode;
+
+	inode = proc_pid_make_inode(dentry->d_sb, task, S_IFLNK |
+				    ((mode & FMODE_READ ) ? S_IRUSR : 0) |
+				    ((mode & FMODE_WRITE) ? S_IWUSR : 0));
+	if (!inode)
+		return ERR_PTR(-ENOENT);
+
+	ei = PROC_I(inode);
+	ei->op.proc_get_link = map_files_get_link;
+
+	inode->i_op = &proc_map_files_link_inode_operations;
+	inode->i_size = 64;
+
+	d_set_d_op(dentry, &tid_map_files_dentry_operations);
+	return d_splice_alias(inode, dentry);
+}
+
+static struct dentry *proc_map_files_lookup(struct inode *dir,
+		struct dentry *dentry, unsigned int flags)
+{
+	unsigned long vm_start, vm_end;
+	struct vm_area_struct *vma;
+	struct task_struct *task;
+	struct dentry *result;
+	struct mm_struct *mm;
+
+	result = ERR_PTR(-ENOENT);
+	task = get_proc_task(dir);
+	if (!task)
+		goto out;
+
+	result = ERR_PTR(-EACCES);
+	if (!ptrace_may_access(task, PTRACE_MODE_READ_FSCREDS))
+		goto out_put_task;
+
+	result = ERR_PTR(-ENOENT);
+	if (dname_to_vma_addr(dentry, &vm_start, &vm_end))
+		goto out_put_task;
+
+	mm = get_task_mm(task);
+	if (!mm)
+		goto out_put_task;
+
+	result = ERR_PTR(-EINTR);
+	if (mmap_read_lock_killable(mm))
+		goto out_put_mm;
+
+	result = ERR_PTR(-ENOENT);
+	vma = find_exact_vma(mm, vm_start, vm_end);
+	if (!vma)
+		goto out_no_vma;
+
+	if (vma->vm_file)
+		result = proc_map_files_instantiate(dentry, task,
+				(void *)(unsigned long)vma->vm_file->f_mode);
+
+out_no_vma:
+	mmap_read_unlock(mm);
+out_put_mm:
+	mmput(mm);
+out_put_task:
+	put_task_struct(task);
+out:
+	return result;
+}
+
+static const struct inode_operations proc_map_files_inode_operations = {
+	.lookup		= proc_map_files_lookup,
+	.permission	= proc_fd_permission,
+	.setattr	= proc_setattr,
+};
+
+static int
+proc_map_files_readdir(struct file *file, struct dir_context *ctx)
+{
+	struct vm_area_struct *vma;
+	struct task_struct *task;
+	struct mm_struct *mm;
+	unsigned long nr_files, pos, i;
+	GENRADIX(struct map_files_info) fa;
+	struct map_files_info *p;
+	int ret;
+	struct vma_iterator vmi;
+
+	genradix_init(&fa);
+
+	ret = -ENOENT;
+	task = get_proc_task(file_inode(file));
+	if (!task)
+		goto out;
+
+	ret = -EACCES;
+	if (!ptrace_may_access(task, PTRACE_MODE_READ_FSCREDS))
+		goto out_put_task;
+
+	ret = 0;
+	if (!dir_emit_dots(file, ctx))
+		goto out_put_task;
+
+	mm = get_task_mm(task);
+	if (!mm)
+		goto out_put_task;
+
+	ret = mmap_read_lock_killable(mm);
+	if (ret) {
+		mmput(mm);
+		goto out_put_task;
+	}
+
+	nr_files = 0;
+
+	/*
+	 * We need two passes here:
+	 *
+	 *  1) Collect vmas of mapped files with mmap_lock taken
+	 *  2) Release mmap_lock and instantiate entries
+	 *
+	 * otherwise we get lockdep complained, since filldir()
+	 * routine might require mmap_lock taken in might_fault().
+	 */
+
+	pos = 2;
+	vma_iter_init(&vmi, mm, 0);
+	for_each_vma(vmi, vma) {
+		if (!vma->vm_file)
+			continue;
+		if (++pos <= ctx->pos)
+			continue;
+
+		p = genradix_ptr_alloc(&fa, nr_files++, GFP_KERNEL);
+		if (!p) {
+			ret = -ENOMEM;
+			mmap_read_unlock(mm);
+			mmput(mm);
+			goto out_put_task;
+		}
+
+		p->start = vma->vm_start;
+		p->end = vma->vm_end;
+		p->mode = vma->vm_file->f_mode;
+	}
+	mmap_read_unlock(mm);
+	mmput(mm);
+
+	for (i = 0; i < nr_files; i++) {
+		char buf[4 * sizeof(long) + 2];	/* max: %lx-%lx\0 */
+		unsigned int len;
+
+		p = genradix_ptr(&fa, i);
+		len = snprintf(buf, sizeof(buf), "%lx-%lx", p->start, p->end);
+		if (!proc_fill_cache(file, ctx,
+				      buf, len,
+				      proc_map_files_instantiate,
+				      task,
+				      (void *)(unsigned long)p->mode))
+			break;
+		ctx->pos++;
+	}
+
+out_put_task:
+	put_task_struct(task);
+out:
+	genradix_free(&fa);
+	return ret;
+}
+
+static const struct file_operations proc_map_files_operations = {
+	.read		= generic_read_dir,
+	.iterate_shared	= proc_map_files_readdir,
+	.llseek		= generic_file_llseek,
+};
+
+#if defined(CONFIG_CHECKPOINT_RESTORE) && defined(CONFIG_POSIX_TIMERS)
+struct timers_private {
+	struct pid *pid;
+	struct task_struct *task;
+	struct sighand_struct *sighand;
+	struct pid_namespace *ns;
+	unsigned long flags;
+};
+
+static void *timers_start(struct seq_file *m, loff_t *pos)
+{
+	struct timers_private *tp = m->private;
+
+	tp->task = get_pid_task(tp->pid, PIDTYPE_PID);
+	if (!tp->task)
+		return ERR_PTR(-ESRCH);
+
+	tp->sighand = lock_task_sighand(tp->task, &tp->flags);
+	if (!tp->sighand)
+		return ERR_PTR(-ESRCH);
+
+	return seq_list_start(&tp->task->signal->posix_timers, *pos);
+}
+
+static void *timers_next(struct seq_file *m, void *v, loff_t *pos)
+{
+	struct timers_private *tp = m->private;
+	return seq_list_next(v, &tp->task->signal->posix_timers, pos);
+}
+
+static void timers_stop(struct seq_file *m, void *v)
+{
+	struct timers_private *tp = m->private;
+
+	if (tp->sighand) {
+		unlock_task_sighand(tp->task, &tp->flags);
+		tp->sighand = NULL;
+	}
+
+	if (tp->task) {
+		put_task_struct(tp->task);
+		tp->task = NULL;
+	}
+}
+
+static int show_timer(struct seq_file *m, void *v)
+{
+	struct k_itimer *timer;
+	struct timers_private *tp = m->private;
+	int notify;
+	static const char * const nstr[] = {
+		[SIGEV_SIGNAL] = "signal",
+		[SIGEV_NONE] = "none",
+		[SIGEV_THREAD] = "thread",
+	};
+
+	timer = list_entry((struct list_head *)v, struct k_itimer, list);
+	notify = timer->it_sigev_notify;
+
+	seq_printf(m, "ID: %d\n", timer->it_id);
+	seq_printf(m, "signal: %d/%px\n",
+		   timer->sigq->info.si_signo,
+		   timer->sigq->info.si_value.sival_ptr);
+	seq_printf(m, "notify: %s/%s.%d\n",
+		   nstr[notify & ~SIGEV_THREAD_ID],
+		   (notify & SIGEV_THREAD_ID) ? "tid" : "pid",
+		   pid_nr_ns(timer->it_pid, tp->ns));
+	seq_printf(m, "ClockID: %d\n", timer->it_clock);
+
+	return 0;
+}
+
+static const struct seq_operations proc_timers_seq_ops = {
+	.start	= timers_start,
+	.next	= timers_next,
+	.stop	= timers_stop,
+	.show	= show_timer,
+};
+
+static int proc_timers_open(struct inode *inode, struct file *file)
+{
+	struct timers_private *tp;
+
+	tp = __seq_open_private(file, &proc_timers_seq_ops,
+			sizeof(struct timers_private));
+	if (!tp)
+		return -ENOMEM;
+
+	tp->pid = proc_pid(inode);
+	tp->ns = proc_pid_ns(inode->i_sb);
+	return 0;
+}
+
+static const struct file_operations proc_timers_operations = {
+	.open		= proc_timers_open,
+	.read		= seq_read,
+	.llseek		= seq_lseek,
+	.release	= seq_release_private,
+};
+#endif
+
+static ssize_t timerslack_ns_write(struct file *file, const char __user *buf,
+					size_t count, loff_t *offset)
+{
+	struct inode *inode = file_inode(file);
+	struct task_struct *p;
+	u64 slack_ns;
+	int err;
+
+	err = kstrtoull_from_user(buf, count, 10, &slack_ns);
+	if (err < 0)
+		return err;
+
+	p = get_proc_task(inode);
+	if (!p)
+		return -ESRCH;
+
+	if (p != current) {
+		rcu_read_lock();
+		if (!ns_capable(__task_cred(p)->user_ns, CAP_SYS_NICE)) {
+			rcu_read_unlock();
+			count = -EPERM;
+			goto out;
+		}
+		rcu_read_unlock();
+
+		err = security_task_setscheduler(p);
+		if (err) {
+			count = err;
+			goto out;
+		}
+	}
+
+	task_lock(p);
+	if (slack_ns == 0)
+		p->timer_slack_ns = p->default_timer_slack_ns;
+	else
+		p->timer_slack_ns = slack_ns;
+	task_unlock(p);
+
+out:
+	put_task_struct(p);
+
+	return count;
+}
+
+static int timerslack_ns_show(struct seq_file *m, void *v)
+{
+	struct inode *inode = m->private;
+	struct task_struct *p;
+	int err = 0;
+
+	p = get_proc_task(inode);
+	if (!p)
+		return -ESRCH;
+
+	if (p != current) {
+		rcu_read_lock();
+		if (!ns_capable(__task_cred(p)->user_ns, CAP_SYS_NICE)) {
+			rcu_read_unlock();
+			err = -EPERM;
+			goto out;
+		}
+		rcu_read_unlock();
+
+		err = security_task_getscheduler(p);
+		if (err)
+			goto out;
+	}
+
+	task_lock(p);
+	seq_printf(m, "%llu\n", p->timer_slack_ns);
+	task_unlock(p);
+
+out:
+	put_task_struct(p);
+
+	return err;
+}
+
+static int timerslack_ns_open(struct inode *inode, struct file *filp)
+{
+	return single_open(filp, timerslack_ns_show, inode);
+}
+
+static const struct file_operations proc_pid_set_timerslack_ns_operations = {
+	.open		= timerslack_ns_open,
+	.read		= seq_read,
+	.write		= timerslack_ns_write,
+	.llseek		= seq_lseek,
+	.release	= single_release,
+};
+
+static struct dentry *proc_pident_instantiate(struct dentry *dentry,
+	struct task_struct *task, const void *ptr)
+{
+	const struct pid_entry *p = ptr;
+	struct inode *inode;
+	struct proc_inode *ei;
+
+	inode = proc_pid_make_inode(dentry->d_sb, task, p->mode);
+	if (!inode)
+		return ERR_PTR(-ENOENT);
+
+	ei = PROC_I(inode);
+	if (S_ISDIR(inode->i_mode))
+		set_nlink(inode, 2);	/* Use getattr to fix if necessary */
+	if (p->iop)
+		inode->i_op = p->iop;
+	if (p->fop)
+		inode->i_fop = p->fop;
+	ei->op = p->op;
+	pid_update_inode(task, inode);
+	d_set_d_op(dentry, &pid_dentry_operations);
+	return d_splice_alias(inode, dentry);
+}
+
+static struct dentry *proc_pident_lookup(struct inode *dir, 
+					 struct dentry *dentry,
+					 const struct pid_entry *p,
+					 const struct pid_entry *end)
+{
+	struct task_struct *task = get_proc_task(dir);
+	struct dentry *res = ERR_PTR(-ENOENT);
+
+	if (!task)
+		goto out_no_task;
+
+	/*
+	 * Yes, it does not scale. And it should not. Don't add
+	 * new entries into /proc/<tgid>/ without very good reasons.
+	 */
+	for (; p < end; p++) {
+		if (p->len != dentry->d_name.len)
+			continue;
+		if (!memcmp(dentry->d_name.name, p->name, p->len)) {
+			res = proc_pident_instantiate(dentry, task, p);
+			break;
+		}
+	}
+	put_task_struct(task);
+out_no_task:
+	return res;
+}
+
+static int proc_pident_readdir(struct file *file, struct dir_context *ctx,
+		const struct pid_entry *ents, unsigned int nents)
+{
+	struct task_struct *task = get_proc_task(file_inode(file));
+	const struct pid_entry *p;
+
+	if (!task)
+		return -ENOENT;
+
+	if (!dir_emit_dots(file, ctx))
+		goto out;
+
+	if (ctx->pos >= nents + 2)
+		goto out;
+
+	for (p = ents + (ctx->pos - 2); p < ents + nents; p++) {
+		if (!proc_fill_cache(file, ctx, p->name, p->len,
+				proc_pident_instantiate, task, p))
+			break;
+		ctx->pos++;
+	}
+out:
+	put_task_struct(task);
+	return 0;
+}
+
+#ifdef CONFIG_SECURITY
+static int proc_pid_attr_open(struct inode *inode, struct file *file)
+{
+	file->private_data = NULL;
+	__mem_open(inode, file, PTRACE_MODE_READ_FSCREDS);
+	return 0;
+}
+
+static ssize_t proc_pid_attr_read(struct file * file, char __user * buf,
+				  size_t count, loff_t *ppos)
+{
+	struct inode * inode = file_inode(file);
+	char *p = NULL;
+	ssize_t length;
+	struct task_struct *task = get_proc_task(inode);
+
+	if (!task)
+		return -ESRCH;
+
+	length = security_getprocattr(task, PROC_I(inode)->op.lsm,
+				      file->f_path.dentry->d_name.name,
+				      &p);
+	put_task_struct(task);
+	if (length > 0)
+		length = simple_read_from_buffer(buf, count, ppos, p, length);
+	kfree(p);
+	return length;
+}
+
+static ssize_t proc_pid_attr_write(struct file * file, const char __user * buf,
+				   size_t count, loff_t *ppos)
+{
+	struct inode * inode = file_inode(file);
+	struct task_struct *task;
+	void *page;
+	int rv;
+
+	/* A task may only write when it was the opener. */
+	if (file->private_data != current->mm)
+		return -EPERM;
+
+	rcu_read_lock();
+	task = pid_task(proc_pid(inode), PIDTYPE_PID);
+	if (!task) {
+		rcu_read_unlock();
+		return -ESRCH;
+	}
+	/* A task may only write its own attributes. */
+	if (current != task) {
+		rcu_read_unlock();
+		return -EACCES;
+	}
+	/* Prevent changes to overridden credentials. */
+	if (current_cred() != current_real_cred()) {
+		rcu_read_unlock();
+		return -EBUSY;
+	}
+	rcu_read_unlock();
+
+	if (count > PAGE_SIZE)
+		count = PAGE_SIZE;
+
+	/* No partial writes. */
+	if (*ppos != 0)
+		return -EINVAL;
+
+	page = memdup_user(buf, count);
+	if (IS_ERR(page)) {
+		rv = PTR_ERR(page);
+		goto out;
+	}
+
+	/* Guard against adverse ptrace interaction */
+	rv = mutex_lock_interruptible(&current->signal->cred_guard_mutex);
+	if (rv < 0)
+		goto out_free;
+
+	rv = security_setprocattr(PROC_I(inode)->op.lsm,
+				  file->f_path.dentry->d_name.name, page,
+				  count);
+	mutex_unlock(&current->signal->cred_guard_mutex);
+out_free:
+	kfree(page);
+out:
+	return rv;
+}
+
+static const struct file_operations proc_pid_attr_operations = {
+	.open		= proc_pid_attr_open,
+	.read		= proc_pid_attr_read,
+	.write		= proc_pid_attr_write,
+	.llseek		= generic_file_llseek,
+	.release	= mem_release,
+};
+
+#define LSM_DIR_OPS(LSM) \
+static int proc_##LSM##_attr_dir_iterate(struct file *filp, \
+			     struct dir_context *ctx) \
+{ \
+	return proc_pident_readdir(filp, ctx, \
+				   LSM##_attr_dir_stuff, \
+				   ARRAY_SIZE(LSM##_attr_dir_stuff)); \
+} \
+\
+static const struct file_operations proc_##LSM##_attr_dir_ops = { \
+	.read		= generic_read_dir, \
+	.iterate	= proc_##LSM##_attr_dir_iterate, \
+	.llseek		= default_llseek, \
+}; \
+\
+static struct dentry *proc_##LSM##_attr_dir_lookup(struct inode *dir, \
+				struct dentry *dentry, unsigned int flags) \
+{ \
+	return proc_pident_lookup(dir, dentry, \
+				  LSM##_attr_dir_stuff, \
+				  LSM##_attr_dir_stuff + ARRAY_SIZE(LSM##_attr_dir_stuff)); \
+} \
+\
+static const struct inode_operations proc_##LSM##_attr_dir_inode_ops = { \
+	.lookup		= proc_##LSM##_attr_dir_lookup, \
+	.getattr	= pid_getattr, \
+	.setattr	= proc_setattr, \
+}
+
+#ifdef CONFIG_SECURITY_SMACK
+static const struct pid_entry smack_attr_dir_stuff[] = {
+	ATTR("smack", "current",	0666),
+};
+LSM_DIR_OPS(smack);
+#endif
+
+#ifdef CONFIG_SECURITY_APPARMOR
+static const struct pid_entry apparmor_attr_dir_stuff[] = {
+	ATTR("apparmor", "current",	0666),
+	ATTR("apparmor", "prev",	0444),
+	ATTR("apparmor", "exec",	0666),
+};
+LSM_DIR_OPS(apparmor);
+#endif
+
+static const struct pid_entry attr_dir_stuff[] = {
+	ATTR(NULL, "current",		0666),
+	ATTR(NULL, "prev",		0444),
+	ATTR(NULL, "exec",		0666),
+	ATTR(NULL, "fscreate",		0666),
+	ATTR(NULL, "keycreate",		0666),
+	ATTR(NULL, "sockcreate",	0666),
+#ifdef CONFIG_SECURITY_SMACK
+	DIR("smack",			0555,
+	    proc_smack_attr_dir_inode_ops, proc_smack_attr_dir_ops),
+#endif
+#ifdef CONFIG_SECURITY_APPARMOR
+	DIR("apparmor",			0555,
+	    proc_apparmor_attr_dir_inode_ops, proc_apparmor_attr_dir_ops),
+#endif
+};
+
+static int proc_attr_dir_readdir(struct file *file, struct dir_context *ctx)
+{
+	return proc_pident_readdir(file, ctx, 
+				   attr_dir_stuff, ARRAY_SIZE(attr_dir_stuff));
+}
+
+static const struct file_operations proc_attr_dir_operations = {
+	.read		= generic_read_dir,
+	.iterate_shared	= proc_attr_dir_readdir,
+	.llseek		= generic_file_llseek,
+};
+
+static struct dentry *proc_attr_dir_lookup(struct inode *dir,
+				struct dentry *dentry, unsigned int flags)
+{
+	return proc_pident_lookup(dir, dentry,
+				  attr_dir_stuff,
+				  attr_dir_stuff + ARRAY_SIZE(attr_dir_stuff));
+}
+
+static const struct inode_operations proc_attr_dir_inode_operations = {
+	.lookup		= proc_attr_dir_lookup,
+	.getattr	= pid_getattr,
+	.setattr	= proc_setattr,
+};
+
+#endif
+
+#ifdef CONFIG_ELF_CORE
+static ssize_t proc_coredump_filter_read(struct file *file, char __user *buf,
+					 size_t count, loff_t *ppos)
+{
+	struct task_struct *task = get_proc_task(file_inode(file));
+	struct mm_struct *mm;
+	char buffer[PROC_NUMBUF];
+	size_t len;
+	int ret;
+
+	if (!task)
+		return -ESRCH;
+
+	ret = 0;
+	mm = get_task_mm(task);
+	if (mm) {
+		len = snprintf(buffer, sizeof(buffer), "%08lx\n",
+			       ((mm->flags & MMF_DUMP_FILTER_MASK) >>
+				MMF_DUMP_FILTER_SHIFT));
+		mmput(mm);
+		ret = simple_read_from_buffer(buf, count, ppos, buffer, len);
+	}
+
+	put_task_struct(task);
+
+	return ret;
+}
+
+static ssize_t proc_coredump_filter_write(struct file *file,
+					  const char __user *buf,
+					  size_t count,
+					  loff_t *ppos)
+{
+	struct task_struct *task;
+	struct mm_struct *mm;
+	unsigned int val;
+	int ret;
+	int i;
+	unsigned long mask;
+
+	ret = kstrtouint_from_user(buf, count, 0, &val);
+	if (ret < 0)
+		return ret;
+
+	ret = -ESRCH;
+	task = get_proc_task(file_inode(file));
+	if (!task)
+		goto out_no_task;
+
+	mm = get_task_mm(task);
+	if (!mm)
+		goto out_no_mm;
+	ret = 0;
+
+	for (i = 0, mask = 1; i < MMF_DUMP_FILTER_BITS; i++, mask <<= 1) {
+		if (val & mask)
+			set_bit(i + MMF_DUMP_FILTER_SHIFT, &mm->flags);
+		else
+			clear_bit(i + MMF_DUMP_FILTER_SHIFT, &mm->flags);
+	}
+
+	mmput(mm);
+ out_no_mm:
+	put_task_struct(task);
+ out_no_task:
+	if (ret < 0)
+		return ret;
+	return count;
+}
+
+static const struct file_operations proc_coredump_filter_operations = {
+	.read		= proc_coredump_filter_read,
+	.write		= proc_coredump_filter_write,
+	.llseek		= generic_file_llseek,
+};
+#endif
+
+#ifdef CONFIG_TASK_IO_ACCOUNTING
+static int do_io_accounting(struct task_struct *task, struct seq_file *m, int whole)
+{
+	struct task_io_accounting acct = task->ioac;
+	unsigned long flags;
+	int result;
+
+	result = down_read_killable(&task->signal->exec_update_lock);
+	if (result)
+		return result;
+
+	if (!ptrace_may_access(task, PTRACE_MODE_READ_FSCREDS)) {
+		result = -EACCES;
+		goto out_unlock;
+	}
+
+	if (whole && lock_task_sighand(task, &flags)) {
+		struct task_struct *t = task;
+
+		task_io_accounting_add(&acct, &task->signal->ioac);
+		while_each_thread(task, t)
+			task_io_accounting_add(&acct, &t->ioac);
+
+		unlock_task_sighand(task, &flags);
+	}
+	seq_printf(m,
+		   "rchar: %llu\n"
+		   "wchar: %llu\n"
+		   "syscr: %llu\n"
+		   "syscw: %llu\n"
+		   "read_bytes: %llu\n"
+		   "write_bytes: %llu\n"
+		   "cancelled_write_bytes: %llu\n",
+		   (unsigned long long)acct.rchar,
+		   (unsigned long long)acct.wchar,
+		   (unsigned long long)acct.syscr,
+		   (unsigned long long)acct.syscw,
+		   (unsigned long long)acct.read_bytes,
+		   (unsigned long long)acct.write_bytes,
+		   (unsigned long long)acct.cancelled_write_bytes);
+	result = 0;
+
+out_unlock:
+	up_read(&task->signal->exec_update_lock);
+	return result;
+}
+
+static int proc_tid_io_accounting(struct seq_file *m, struct pid_namespace *ns,
+				  struct pid *pid, struct task_struct *task)
+{
+	return do_io_accounting(task, m, 0);
+}
+
+static int proc_tgid_io_accounting(struct seq_file *m, struct pid_namespace *ns,
+				   struct pid *pid, struct task_struct *task)
+{
+	return do_io_accounting(task, m, 1);
+}
+#endif /* CONFIG_TASK_IO_ACCOUNTING */
+
+#ifdef CONFIG_USER_NS
+static int proc_id_map_open(struct inode *inode, struct file *file,
+	const struct seq_operations *seq_ops)
+{
+	struct user_namespace *ns = NULL;
+	struct task_struct *task;
+	struct seq_file *seq;
+	int ret = -EINVAL;
+
+	task = get_proc_task(inode);
+	if (task) {
+		rcu_read_lock();
+		ns = get_user_ns(task_cred_xxx(task, user_ns));
+		rcu_read_unlock();
+		put_task_struct(task);
+	}
+	if (!ns)
+		goto err;
+
+	ret = seq_open(file, seq_ops);
+	if (ret)
+		goto err_put_ns;
+
+	seq = file->private_data;
+	seq->private = ns;
+
+	return 0;
+err_put_ns:
+	put_user_ns(ns);
+err:
+	return ret;
+}
+
+static int proc_id_map_release(struct inode *inode, struct file *file)
+{
+	struct seq_file *seq = file->private_data;
+	struct user_namespace *ns = seq->private;
+	put_user_ns(ns);
+	return seq_release(inode, file);
+}
+
+static int proc_uid_map_open(struct inode *inode, struct file *file)
+{
+	return proc_id_map_open(inode, file, &proc_uid_seq_operations);
+}
+
+static int proc_gid_map_open(struct inode *inode, struct file *file)
+{
+	return proc_id_map_open(inode, file, &proc_gid_seq_operations);
+}
+
+static int proc_projid_map_open(struct inode *inode, struct file *file)
+{
+	return proc_id_map_open(inode, file, &proc_projid_seq_operations);
+}
+
+static const struct file_operations proc_uid_map_operations = {
+	.open		= proc_uid_map_open,
+	.write		= proc_uid_map_write,
+	.read		= seq_read,
+	.llseek		= seq_lseek,
+	.release	= proc_id_map_release,
+};
+
+static const struct file_operations proc_gid_map_operations = {
+	.open		= proc_gid_map_open,
+	.write		= proc_gid_map_write,
+	.read		= seq_read,
+	.llseek		= seq_lseek,
+	.release	= proc_id_map_release,
+};
+
+static const struct file_operations proc_projid_map_operations = {
+	.open		= proc_projid_map_open,
+	.write		= proc_projid_map_write,
+	.read		= seq_read,
+	.llseek		= seq_lseek,
+	.release	= proc_id_map_release,
+};
+
+static int proc_setgroups_open(struct inode *inode, struct file *file)
+{
+	struct user_namespace *ns = NULL;
+	struct task_struct *task;
+	int ret;
+
+	ret = -ESRCH;
+	task = get_proc_task(inode);
+	if (task) {
+		rcu_read_lock();
+		ns = get_user_ns(task_cred_xxx(task, user_ns));
+		rcu_read_unlock();
+		put_task_struct(task);
+	}
+	if (!ns)
+		goto err;
+
+	if (file->f_mode & FMODE_WRITE) {
+		ret = -EACCES;
+		if (!ns_capable(ns, CAP_SYS_ADMIN))
+			goto err_put_ns;
+	}
+
+	ret = single_open(file, &proc_setgroups_show, ns);
+	if (ret)
+		goto err_put_ns;
+
+	return 0;
+err_put_ns:
+	put_user_ns(ns);
+err:
+	return ret;
+}
+
+static int proc_setgroups_release(struct inode *inode, struct file *file)
+{
+	struct seq_file *seq = file->private_data;
+	struct user_namespace *ns = seq->private;
+	int ret = single_release(inode, file);
+	put_user_ns(ns);
+	return ret;
+}
+
+static const struct file_operations proc_setgroups_operations = {
+	.open		= proc_setgroups_open,
+	.write		= proc_setgroups_write,
+	.read		= seq_read,
+	.llseek		= seq_lseek,
+	.release	= proc_setgroups_release,
+};
+#endif /* CONFIG_USER_NS */
+
+static int proc_pid_personality(struct seq_file *m, struct pid_namespace *ns,
+				struct pid *pid, struct task_struct *task)
+{
+	int err = lock_trace(task);
+	if (!err) {
+		seq_printf(m, "%08x\n", task->personality);
+		unlock_trace(task);
+	}
+	return err;
+}
+
+#ifdef CONFIG_LIVEPATCH
+static int proc_pid_patch_state(struct seq_file *m, struct pid_namespace *ns,
+				struct pid *pid, struct task_struct *task)
+{
+	seq_printf(m, "%d\n", task->patch_state);
+	return 0;
+}
+#endif /* CONFIG_LIVEPATCH */
+
+#ifdef CONFIG_KSM
+static int proc_pid_ksm_merging_pages(struct seq_file *m, struct pid_namespace *ns,
+				struct pid *pid, struct task_struct *task)
+{
+	struct mm_struct *mm;
+
+	mm = get_task_mm(task);
+	if (mm) {
+		seq_printf(m, "%lu\n", mm->ksm_merging_pages);
+		mmput(mm);
+	}
+
+	return 0;
+}
+static int proc_pid_ksm_stat(struct seq_file *m, struct pid_namespace *ns,
+				struct pid *pid, struct task_struct *task)
+{
+	struct mm_struct *mm;
+
+	mm = get_task_mm(task);
+	if (mm) {
+		seq_printf(m, "ksm_rmap_items %lu\n", mm->ksm_rmap_items);
+		mmput(mm);
+	}
+
+	return 0;
+}
+#endif /* CONFIG_KSM */
+
+#ifdef CONFIG_STACKLEAK_METRICS
+static int proc_stack_depth(struct seq_file *m, struct pid_namespace *ns,
+				struct pid *pid, struct task_struct *task)
+{
+	unsigned long prev_depth = THREAD_SIZE -
+				(task->prev_lowest_stack & (THREAD_SIZE - 1));
+	unsigned long depth = THREAD_SIZE -
+				(task->lowest_stack & (THREAD_SIZE - 1));
+
+	seq_printf(m, "previous stack depth: %lu\nstack depth: %lu\n",
+							prev_depth, depth);
+	return 0;
+}
+#endif /* CONFIG_STACKLEAK_METRICS */
+
+/*
+ * Thread groups
+ */
+static const struct file_operations proc_task_operations;
+static const struct inode_operations proc_task_inode_operations;
+
+static const struct pid_entry tgid_base_stuff[] = {
+	DIR("task",       S_IRUGO|S_IXUGO, proc_task_inode_operations, proc_task_operations),
+	DIR("fd",         S_IRUSR|S_IXUSR, proc_fd_inode_operations, proc_fd_operations),
+	DIR("map_files",  S_IRUSR|S_IXUSR, proc_map_files_inode_operations, proc_map_files_operations),
+	DIR("fdinfo",     S_IRUGO|S_IXUGO, proc_fdinfo_inode_operations, proc_fdinfo_operations),
+	DIR("ns",	  S_IRUSR|S_IXUGO, proc_ns_dir_inode_operations, proc_ns_dir_operations),
+#ifdef CONFIG_NET
+	DIR("net",        S_IRUGO|S_IXUGO, proc_net_inode_operations, proc_net_operations),
+#endif
+	REG("environ",    S_IRUSR, proc_environ_operations),
+	REG("auxv",       S_IRUSR, proc_auxv_operations),
+	ONE("status",     S_IRUGO, proc_pid_status),
+	ONE("personality", S_IRUSR, proc_pid_personality),
+	ONE("limits",	  S_IRUGO, proc_pid_limits),
+#ifdef CONFIG_SCHED_DEBUG
+	REG("sched",      S_IRUGO|S_IWUSR, proc_pid_sched_operations),
+#endif
+#ifdef CONFIG_SCHED_AUTOGROUP
+	REG("autogroup",  S_IRUGO|S_IWUSR, proc_pid_sched_autogroup_operations),
+#endif
+#ifdef CONFIG_TIME_NS
+	REG("timens_offsets",  S_IRUGO|S_IWUSR, proc_timens_offsets_operations),
+#endif
+	REG("comm",      S_IRUGO|S_IWUSR, proc_pid_set_comm_operations),
+#ifdef CONFIG_HAVE_ARCH_TRACEHOOK
+	ONE("syscall",    S_IRUSR, proc_pid_syscall),
+#endif
+	REG("cmdline",    S_IRUGO, proc_pid_cmdline_ops),
+	ONE("stat",       S_IRUGO, proc_tgid_stat),
+	ONE("statm",      S_IRUGO, proc_pid_statm),
+	REG("maps",       S_IRUGO, proc_pid_maps_operations),
+#ifdef CONFIG_NUMA
+	REG("numa_maps",  S_IRUGO, proc_pid_numa_maps_operations),
+#endif
+	REG("mem",        S_IRUSR|S_IWUSR, proc_mem_operations),
+	LNK("cwd",        proc_cwd_link),
+	LNK("root",       proc_root_link),
+	LNK("exe",        proc_exe_link),
+	REG("mounts",     S_IRUGO, proc_mounts_operations),
+	REG("mountinfo",  S_IRUGO, proc_mountinfo_operations),
+	REG("mountstats", S_IRUSR, proc_mountstats_operations),
+#ifdef CONFIG_PROC_PAGE_MONITOR
+	REG("clear_refs", S_IWUSR, proc_clear_refs_operations),
+	REG("smaps",      S_IRUGO, proc_pid_smaps_operations),
+	REG("smaps_rollup", S_IRUGO, proc_pid_smaps_rollup_operations),
+	REG("pagemap",    S_IRUSR, proc_pagemap_operations),
+#endif
+#ifdef CONFIG_SECURITY
+	DIR("attr",       S_IRUGO|S_IXUGO, proc_attr_dir_inode_operations, proc_attr_dir_operations),
+#endif
+#ifdef CONFIG_KALLSYMS
+	ONE("wchan",      S_IRUGO, proc_pid_wchan),
+#endif
+#ifdef CONFIG_STACKTRACE
+	ONE("stack",      S_IRUSR, proc_pid_stack),
+#endif
+#ifdef CONFIG_SCHED_INFO
+	ONE("schedstat",  S_IRUGO, proc_pid_schedstat),
+#endif
+#ifdef CONFIG_LATENCYTOP
+	REG("latency",  S_IRUGO, proc_lstats_operations),
+#endif
+#ifdef CONFIG_PROC_PID_CPUSET
+	ONE("cpuset",     S_IRUGO, proc_cpuset_show),
+#endif
+#ifdef CONFIG_CGROUPS
+	ONE("cgroup",  S_IRUGO, proc_cgroup_show),
+#endif
+#ifdef CONFIG_PROC_CPU_RESCTRL
+	ONE("cpu_resctrl_groups", S_IRUGO, proc_resctrl_show),
+#endif
+	ONE("oom_score",  S_IRUGO, proc_oom_score),
+	REG("oom_adj",    S_IRUGO|S_IWUSR, proc_oom_adj_operations),
+	REG("oom_score_adj", S_IRUGO|S_IWUSR, proc_oom_score_adj_operations),
+#ifdef CONFIG_AUDIT
+	REG("loginuid",   S_IWUSR|S_IRUGO, proc_loginuid_operations),
+	REG("sessionid",  S_IRUGO, proc_sessionid_operations),
+#endif
+#ifdef CONFIG_FAULT_INJECTION
+	REG("make-it-fail", S_IRUGO|S_IWUSR, proc_fault_inject_operations),
+	REG("fail-nth", 0644, proc_fail_nth_operations),
+#endif
+#ifdef CONFIG_ELF_CORE
+	REG("coredump_filter", S_IRUGO|S_IWUSR, proc_coredump_filter_operations),
+#endif
+#ifdef CONFIG_TASK_IO_ACCOUNTING
+	ONE("io",	S_IRUSR, proc_tgid_io_accounting),
+#endif
+#ifdef CONFIG_USER_NS
+	REG("uid_map",    S_IRUGO|S_IWUSR, proc_uid_map_operations),
+	REG("gid_map",    S_IRUGO|S_IWUSR, proc_gid_map_operations),
+	REG("projid_map", S_IRUGO|S_IWUSR, proc_projid_map_operations),
+	REG("setgroups",  S_IRUGO|S_IWUSR, proc_setgroups_operations),
+#endif
+#if defined(CONFIG_CHECKPOINT_RESTORE) && defined(CONFIG_POSIX_TIMERS)
+	REG("timers",	  S_IRUGO, proc_timers_operations),
+#endif
+	REG("timerslack_ns", S_IRUGO|S_IWUGO, proc_pid_set_timerslack_ns_operations),
+#ifdef CONFIG_LIVEPATCH
+	ONE("patch_state",  S_IRUSR, proc_pid_patch_state),
+#endif
+#ifdef CONFIG_STACKLEAK_METRICS
+	ONE("stack_depth", S_IRUGO, proc_stack_depth),
+#endif
+#ifdef CONFIG_PROC_PID_ARCH_STATUS
+	ONE("arch_status", S_IRUGO, proc_pid_arch_status),
+#endif
+#ifdef CONFIG_SECCOMP_CACHE_DEBUG
+	ONE("seccomp_cache", S_IRUSR, proc_pid_seccomp_cache),
+#endif
+#ifdef CONFIG_KSM
+	ONE("ksm_merging_pages",  S_IRUSR, proc_pid_ksm_merging_pages),
+	ONE("ksm_stat",  S_IRUSR, proc_pid_ksm_stat),
+#endif
+};
+
+static int proc_tgid_base_readdir(struct file *file, struct dir_context *ctx)
+{
+	return proc_pident_readdir(file, ctx,
+				   tgid_base_stuff, ARRAY_SIZE(tgid_base_stuff));
+}
+
+static const struct file_operations proc_tgid_base_operations = {
+	.read		= generic_read_dir,
+	.iterate_shared	= proc_tgid_base_readdir,
+	.llseek		= generic_file_llseek,
+};
+
+struct pid *tgid_pidfd_to_pid(const struct file *file)
+{
+	if (file->f_op != &proc_tgid_base_operations)
+		return ERR_PTR(-EBADF);
+
+	return proc_pid(file_inode(file));
+}
+
+static struct dentry *proc_tgid_base_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags)
+{
+	return proc_pident_lookup(dir, dentry,
+				  tgid_base_stuff,
+				  tgid_base_stuff + ARRAY_SIZE(tgid_base_stuff));
+}
+
+static const struct inode_operations proc_tgid_base_inode_operations = {
+	.lookup		= proc_tgid_base_lookup,
+	.getattr	= pid_getattr,
+	.setattr	= proc_setattr,
+	.permission	= proc_pid_permission,
+};
+
+/**
+ * proc_flush_pid -  Remove dcache entries for @pid from the /proc dcache.
+ * @pid: pid that should be flushed.
+ *
+ * This function walks a list of inodes (that belong to any proc
+ * filesystem) that are attached to the pid and flushes them from
+ * the dentry cache.
+ *
+ * It is safe and reasonable to cache /proc entries for a task until
+ * that task exits.  After that they just clog up the dcache with
+ * useless entries, possibly causing useful dcache entries to be
+ * flushed instead.  This routine is provided to flush those useless
+ * dcache entries when a process is reaped.
+ *
+ * NOTE: This routine is just an optimization so it does not guarantee
+ *       that no dcache entries will exist after a process is reaped
+ *       it just makes it very unlikely that any will persist.
+ */
+
+void proc_flush_pid(struct pid *pid)
+{
+	proc_invalidate_siblings_dcache(&pid->inodes, &pid->lock);
+}
+
+static struct dentry *proc_pid_instantiate(struct dentry * dentry,
+				   struct task_struct *task, const void *ptr)
+{
+	struct inode *inode;
+
+	inode = proc_pid_make_base_inode(dentry->d_sb, task,
+					 S_IFDIR | S_IRUGO | S_IXUGO);
+	if (!inode)
+		return ERR_PTR(-ENOENT);
+
+	inode->i_op = &proc_tgid_base_inode_operations;
+	inode->i_fop = &proc_tgid_base_operations;
+	inode->i_flags|=S_IMMUTABLE;
+
+	set_nlink(inode, nlink_tgid);
+	pid_update_inode(task, inode);
+
+	d_set_d_op(dentry, &pid_dentry_operations);
+	return d_splice_alias(inode, dentry);
+}
+
+struct dentry *proc_pid_lookup(struct dentry *dentry, unsigned int flags)
+{
+	struct task_struct *task;
+	unsigned tgid;
+	struct proc_fs_info *fs_info;
+	struct pid_namespace *ns;
+	struct dentry *result = ERR_PTR(-ENOENT);
+
+	tgid = name_to_int(&dentry->d_name);
+	if (tgid == ~0U)
+		goto out;
+
+	fs_info = proc_sb_info(dentry->d_sb);
+	ns = fs_info->pid_ns;
+	rcu_read_lock();
+	task = find_task_by_pid_ns(tgid, ns);
+	if (task)
+		get_task_struct(task);
+	rcu_read_unlock();
+	if (!task)
+		goto out;
+
+	/* Limit procfs to only ptraceable tasks */
+	if (fs_info->hide_pid == HIDEPID_NOT_PTRACEABLE) {
+		if (!has_pid_permissions(fs_info, task, HIDEPID_NO_ACCESS))
+			goto out_put_task;
+	}
+
+	result = proc_pid_instantiate(dentry, task, NULL);
+out_put_task:
+	put_task_struct(task);
+out:
+	return result;
+}
+
+/*
+ * Find the first task with tgid >= tgid
+ *
+ */
+struct tgid_iter {
+	unsigned int tgid;
+	struct task_struct *task;
+};
+static struct tgid_iter next_tgid(struct pid_namespace *ns, struct tgid_iter iter)
+{
+	struct pid *pid;
+
+	if (iter.task)
+		put_task_struct(iter.task);
+	rcu_read_lock();
+retry:
+	iter.task = NULL;
+	pid = find_ge_pid(iter.tgid, ns);
+	if (pid) {
+		iter.tgid = pid_nr_ns(pid, ns);
+		iter.task = pid_task(pid, PIDTYPE_TGID);
+		if (!iter.task) {
+			iter.tgid += 1;
+			goto retry;
+		}
+		get_task_struct(iter.task);
+	}
+	rcu_read_unlock();
+	return iter;
+}
+
+#define TGID_OFFSET (FIRST_PROCESS_ENTRY + 2)
+
+/* for the /proc/ directory itself, after non-process stuff has been done */
+int proc_pid_readdir(struct file *file, struct dir_context *ctx)
+{
+	struct tgid_iter iter;
+	struct proc_fs_info *fs_info = proc_sb_info(file_inode(file)->i_sb);
+	struct pid_namespace *ns = proc_pid_ns(file_inode(file)->i_sb);
+	loff_t pos = ctx->pos;
+
+	if (pos >= PID_MAX_LIMIT + TGID_OFFSET)
+		return 0;
+
+	if (pos == TGID_OFFSET - 2) {
+		struct inode *inode = d_inode(fs_info->proc_self);
+		if (!dir_emit(ctx, "self", 4, inode->i_ino, DT_LNK))
+			return 0;
+		ctx->pos = pos = pos + 1;
+	}
+	if (pos == TGID_OFFSET - 1) {
+		struct inode *inode = d_inode(fs_info->proc_thread_self);
+		if (!dir_emit(ctx, "thread-self", 11, inode->i_ino, DT_LNK))
+			return 0;
+		ctx->pos = pos = pos + 1;
+	}
+	iter.tgid = pos - TGID_OFFSET;
+	iter.task = NULL;
+	for (iter = next_tgid(ns, iter);
+	     iter.task;
+	     iter.tgid += 1, iter = next_tgid(ns, iter)) {
+		char name[10 + 1];
+		unsigned int len;
+
+		cond_resched();
+		if (!has_pid_permissions(fs_info, iter.task, HIDEPID_INVISIBLE))
+			continue;
+
+		len = snprintf(name, sizeof(name), "%u", iter.tgid);
+		ctx->pos = iter.tgid + TGID_OFFSET;
+		if (!proc_fill_cache(file, ctx, name, len,
+				     proc_pid_instantiate, iter.task, NULL)) {
+			put_task_struct(iter.task);
+			return 0;
+		}
+	}
+	ctx->pos = PID_MAX_LIMIT + TGID_OFFSET;
+	return 0;
+}
+
+/*
+ * proc_tid_comm_permission is a special permission function exclusively
+ * used for the node /proc/<pid>/task/<tid>/comm.
+ * It bypasses generic permission checks in the case where a task of the same
+ * task group attempts to access the node.
+ * The rationale behind this is that glibc and bionic access this node for
+ * cross thread naming (pthread_set/getname_np(!self)). However, if
+ * PR_SET_DUMPABLE gets set to 0 this node among others becomes uid=0 gid=0,
+ * which locks out the cross thread naming implementation.
+ * This function makes sure that the node is always accessible for members of
+ * same thread group.
+ */
+static int proc_tid_comm_permission(struct user_namespace *mnt_userns,
+				    struct inode *inode, int mask)
+{
+	bool is_same_tgroup;
+	struct task_struct *task;
+
+	task = get_proc_task(inode);
+	if (!task)
+		return -ESRCH;
+	is_same_tgroup = same_thread_group(current, task);
+	put_task_struct(task);
+
+	if (likely(is_same_tgroup && !(mask & MAY_EXEC))) {
+		/* This file (/proc/<pid>/task/<tid>/comm) can always be
+		 * read or written by the members of the corresponding
+		 * thread group.
+		 */
+		return 0;
+	}
+
+	return generic_permission(&init_user_ns, inode, mask);
+}
+
+static const struct inode_operations proc_tid_comm_inode_operations = {
+		.setattr	= proc_setattr,
+		.permission	= proc_tid_comm_permission,
+};
+
+/*
+ * Tasks
+ */
+static const struct pid_entry tid_base_stuff[] = {
+	DIR("fd",        S_IRUSR|S_IXUSR, proc_fd_inode_operations, proc_fd_operations),
+	DIR("fdinfo",    S_IRUGO|S_IXUGO, proc_fdinfo_inode_operations, proc_fdinfo_operations),
+	DIR("ns",	 S_IRUSR|S_IXUGO, proc_ns_dir_inode_operations, proc_ns_dir_operations),
+#ifdef CONFIG_NET
+	DIR("net",        S_IRUGO|S_IXUGO, proc_net_inode_operations, proc_net_operations),
+#endif
+	REG("environ",   S_IRUSR, proc_environ_operations),
+	REG("auxv",      S_IRUSR, proc_auxv_operations),
+	ONE("status",    S_IRUGO, proc_pid_status),
+	ONE("personality", S_IRUSR, proc_pid_personality),
+	ONE("limits",	 S_IRUGO, proc_pid_limits),
+#ifdef CONFIG_SCHED_DEBUG
+	REG("sched",     S_IRUGO|S_IWUSR, proc_pid_sched_operations),
+#endif
+	NOD("comm",      S_IFREG|S_IRUGO|S_IWUSR,
+			 &proc_tid_comm_inode_operations,
+			 &proc_pid_set_comm_operations, {}),
+#ifdef CONFIG_HAVE_ARCH_TRACEHOOK
+	ONE("syscall",   S_IRUSR, proc_pid_syscall),
+#endif
+	REG("cmdline",   S_IRUGO, proc_pid_cmdline_ops),
+	ONE("stat",      S_IRUGO, proc_tid_stat),
+	ONE("statm",     S_IRUGO, proc_pid_statm),
+	REG("maps",      S_IRUGO, proc_pid_maps_operations),
+#ifdef CONFIG_PROC_CHILDREN
+	REG("children",  S_IRUGO, proc_tid_children_operations),
+#endif
+#ifdef CONFIG_NUMA
+	REG("numa_maps", S_IRUGO, proc_pid_numa_maps_operations),
+#endif
+	REG("mem",       S_IRUSR|S_IWUSR, proc_mem_operations),
+	LNK("cwd",       proc_cwd_link),
+	LNK("root",      proc_root_link),
+	LNK("exe",       proc_exe_link),
+	REG("mounts",    S_IRUGO, proc_mounts_operations),
+	REG("mountinfo",  S_IRUGO, proc_mountinfo_operations),
+#ifdef CONFIG_PROC_PAGE_MONITOR
+	REG("clear_refs", S_IWUSR, proc_clear_refs_operations),
+	REG("smaps",     S_IRUGO, proc_pid_smaps_operations),
+	REG("smaps_rollup", S_IRUGO, proc_pid_smaps_rollup_operations),
+	REG("pagemap",    S_IRUSR, proc_pagemap_operations),
+#endif
+#ifdef CONFIG_SECURITY
+	DIR("attr",      S_IRUGO|S_IXUGO, proc_attr_dir_inode_operations, proc_attr_dir_operations),
+#endif
+#ifdef CONFIG_KALLSYMS
+	ONE("wchan",     S_IRUGO, proc_pid_wchan),
+#endif
+#ifdef CONFIG_STACKTRACE
+	ONE("stack",      S_IRUSR, proc_pid_stack),
+#endif
+#ifdef CONFIG_SCHED_INFO
+	ONE("schedstat", S_IRUGO, proc_pid_schedstat),
+#endif
+#ifdef CONFIG_LATENCYTOP
+	REG("latency",  S_IRUGO, proc_lstats_operations),
+#endif
+#ifdef CONFIG_PROC_PID_CPUSET
+	ONE("cpuset",    S_IRUGO, proc_cpuset_show),
+#endif
+#ifdef CONFIG_CGROUPS
+	ONE("cgroup",  S_IRUGO, proc_cgroup_show),
+#endif
+#ifdef CONFIG_PROC_CPU_RESCTRL
+	ONE("cpu_resctrl_groups", S_IRUGO, proc_resctrl_show),
+#endif
+	ONE("oom_score", S_IRUGO, proc_oom_score),
+	REG("oom_adj",   S_IRUGO|S_IWUSR, proc_oom_adj_operations),
+	REG("oom_score_adj", S_IRUGO|S_IWUSR, proc_oom_score_adj_operations),
+#ifdef CONFIG_AUDIT
+	REG("loginuid",  S_IWUSR|S_IRUGO, proc_loginuid_operations),
+	REG("sessionid",  S_IRUGO, proc_sessionid_operations),
+#endif
+#ifdef CONFIG_FAULT_INJECTION
+	REG("make-it-fail", S_IRUGO|S_IWUSR, proc_fault_inject_operations),
+	REG("fail-nth", 0644, proc_fail_nth_operations),
+#endif
+#ifdef CONFIG_TASK_IO_ACCOUNTING
+	ONE("io",	S_IRUSR, proc_tid_io_accounting),
+#endif
+#ifdef CONFIG_USER_NS
+	REG("uid_map",    S_IRUGO|S_IWUSR, proc_uid_map_operations),
+	REG("gid_map",    S_IRUGO|S_IWUSR, proc_gid_map_operations),
+	REG("projid_map", S_IRUGO|S_IWUSR, proc_projid_map_operations),
+	REG("setgroups",  S_IRUGO|S_IWUSR, proc_setgroups_operations),
+#endif
+#ifdef CONFIG_LIVEPATCH
+	ONE("patch_state",  S_IRUSR, proc_pid_patch_state),
+#endif
+#ifdef CONFIG_PROC_PID_ARCH_STATUS
+	ONE("arch_status", S_IRUGO, proc_pid_arch_status),
+#endif
+#ifdef CONFIG_SECCOMP_CACHE_DEBUG
+	ONE("seccomp_cache", S_IRUSR, proc_pid_seccomp_cache),
+#endif
+#ifdef CONFIG_KSM
+	ONE("ksm_merging_pages",  S_IRUSR, proc_pid_ksm_merging_pages),
+	ONE("ksm_stat",  S_IRUSR, proc_pid_ksm_stat),
+#endif
+};
+
+static int proc_tid_base_readdir(struct file *file, struct dir_context *ctx)
+{
+	return proc_pident_readdir(file, ctx,
+				   tid_base_stuff, ARRAY_SIZE(tid_base_stuff));
+}
+
+static struct dentry *proc_tid_base_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags)
+{
+	return proc_pident_lookup(dir, dentry,
+				  tid_base_stuff,
+				  tid_base_stuff + ARRAY_SIZE(tid_base_stuff));
+}
+
+static const struct file_operations proc_tid_base_operations = {
+	.read		= generic_read_dir,
+	.iterate_shared	= proc_tid_base_readdir,
+	.llseek		= generic_file_llseek,
+};
+
+static const struct inode_operations proc_tid_base_inode_operations = {
+	.lookup		= proc_tid_base_lookup,
+	.getattr	= pid_getattr,
+	.setattr	= proc_setattr,
+};
+
+static struct dentry *proc_task_instantiate(struct dentry *dentry,
+	struct task_struct *task, const void *ptr)
+{
+	struct inode *inode;
+	inode = proc_pid_make_base_inode(dentry->d_sb, task,
+					 S_IFDIR | S_IRUGO | S_IXUGO);
+	if (!inode)
+		return ERR_PTR(-ENOENT);
+
+	inode->i_op = &proc_tid_base_inode_operations;
+	inode->i_fop = &proc_tid_base_operations;
+	inode->i_flags |= S_IMMUTABLE;
+
+	set_nlink(inode, nlink_tid);
+	pid_update_inode(task, inode);
+
+	d_set_d_op(dentry, &pid_dentry_operations);
+	return d_splice_alias(inode, dentry);
+}
+
+static struct dentry *proc_task_lookup(struct inode *dir, struct dentry * dentry, unsigned int flags)
+{
+	struct task_struct *task;
+	struct task_struct *leader = get_proc_task(dir);
+	unsigned tid;
+	struct proc_fs_info *fs_info;
+	struct pid_namespace *ns;
+	struct dentry *result = ERR_PTR(-ENOENT);
+
+	if (!leader)
+		goto out_no_task;
+
+	tid = name_to_int(&dentry->d_name);
+	if (tid == ~0U)
+		goto out;
+
+	fs_info = proc_sb_info(dentry->d_sb);
+	ns = fs_info->pid_ns;
+	rcu_read_lock();
+	task = find_task_by_pid_ns(tid, ns);
+	if (task)
+		get_task_struct(task);
+	rcu_read_unlock();
+	if (!task)
+		goto out;
+	if (!same_thread_group(leader, task))
+		goto out_drop_task;
+
+	result = proc_task_instantiate(dentry, task, NULL);
+out_drop_task:
+	put_task_struct(task);
+out:
+	put_task_struct(leader);
+out_no_task:
+	return result;
+}
+
+/*
+ * Find the first tid of a thread group to return to user space.
+ *
+ * Usually this is just the thread group leader, but if the users
+ * buffer was too small or there was a seek into the middle of the
+ * directory we have more work todo.
+ *
+ * In the case of a short read we start with find_task_by_pid.
+ *
+ * In the case of a seek we start with the leader and walk nr
+ * threads past it.
+ */
+static struct task_struct *first_tid(struct pid *pid, int tid, loff_t f_pos,
+					struct pid_namespace *ns)
+{
+	struct task_struct *pos, *task;
+	unsigned long nr = f_pos;
+
+	if (nr != f_pos)	/* 32bit overflow? */
+		return NULL;
+
+	rcu_read_lock();
+	task = pid_task(pid, PIDTYPE_PID);
+	if (!task)
+		goto fail;
+
+	/* Attempt to start with the tid of a thread */
+	if (tid && nr) {
+		pos = find_task_by_pid_ns(tid, ns);
+		if (pos && same_thread_group(pos, task))
+			goto found;
+	}
+
+	/* If nr exceeds the number of threads there is nothing todo */
+	if (nr >= get_nr_threads(task))
+		goto fail;
+
+	/* If we haven't found our starting place yet start
+	 * with the leader and walk nr threads forward.
+	 */
+	pos = task = task->group_leader;
+	do {
+		if (!nr--)
+			goto found;
+	} while_each_thread(task, pos);
+fail:
+	pos = NULL;
+	goto out;
+found:
+	get_task_struct(pos);
+out:
+	rcu_read_unlock();
+	return pos;
+}
+
+/*
+ * Find the next thread in the thread list.
+ * Return NULL if there is an error or no next thread.
+ *
+ * The reference to the input task_struct is released.
+ */
+static struct task_struct *next_tid(struct task_struct *start)
+{
+	struct task_struct *pos = NULL;
+	rcu_read_lock();
+	if (pid_alive(start)) {
+		pos = next_thread(start);
+		if (thread_group_leader(pos))
+			pos = NULL;
+		else
+			get_task_struct(pos);
+	}
+	rcu_read_unlock();
+	put_task_struct(start);
+	return pos;
+}
+
+/* for the /proc/TGID/task/ directories */
+static int proc_task_readdir(struct file *file, struct dir_context *ctx)
+{
+	struct inode *inode = file_inode(file);
+	struct task_struct *task;
+	struct pid_namespace *ns;
+	int tid;
+
+	if (proc_inode_is_dead(inode))
+		return -ENOENT;
+
+	if (!dir_emit_dots(file, ctx))
+		return 0;
+
+	/* f_version caches the tgid value that the last readdir call couldn't
+	 * return. lseek aka telldir automagically resets f_version to 0.
+	 */
+	ns = proc_pid_ns(inode->i_sb);
+	tid = (int)file->f_version;
+	file->f_version = 0;
+	for (task = first_tid(proc_pid(inode), tid, ctx->pos - 2, ns);
+	     task;
+	     task = next_tid(task), ctx->pos++) {
+		char name[10 + 1];
+		unsigned int len;
+
+		tid = task_pid_nr_ns(task, ns);
+		if (!tid)
+			continue;	/* The task has just exited. */
+		len = snprintf(name, sizeof(name), "%u", tid);
+		if (!proc_fill_cache(file, ctx, name, len,
+				proc_task_instantiate, task, NULL)) {
+			/* returning this tgid failed, save it as the first
+			 * pid for the next readir call */
+			file->f_version = (u64)tid;
+			put_task_struct(task);
+			break;
+		}
+	}
+
+	return 0;
+}
+
+static int proc_task_getattr(struct user_namespace *mnt_userns,
+			     const struct path *path, struct kstat *stat,
+			     u32 request_mask, unsigned int query_flags)
+{
+	struct inode *inode = d_inode(path->dentry);
+	struct task_struct *p = get_proc_task(inode);
+	generic_fillattr(&init_user_ns, inode, stat);
+
+	if (p) {
+		stat->nlink += get_nr_threads(p);
+		put_task_struct(p);
+	}
+
+	return 0;
+}
+
+static const struct inode_operations proc_task_inode_operations = {
+	.lookup		= proc_task_lookup,
+	.getattr	= proc_task_getattr,
+	.setattr	= proc_setattr,
+	.permission	= proc_pid_permission,
+};
+
+static const struct file_operations proc_task_operations = {
+	.read		= generic_read_dir,
+	.iterate_shared	= proc_task_readdir,
+	.llseek		= generic_file_llseek,
+};
+
+void __init set_proc_pid_nlink(void)
+{
+	nlink_tid = pid_entry_nlink(tid_base_stuff, ARRAY_SIZE(tid_base_stuff));
+	nlink_tgid = pid_entry_nlink(tgid_base_stuff, ARRAY_SIZE(tgid_base_stuff));
+}
diff --git a/fs/proc/bootconfig.c b/fs/proc/bootconfig.c
new file mode 100644
index 000000000..2e244ada1
--- /dev/null
+++ b/fs/proc/bootconfig.c
@@ -0,0 +1,96 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * /proc/bootconfig - Extra boot configuration
+ */
+#include <linux/fs.h>
+#include <linux/init.h>
+#include <linux/printk.h>
+#include <linux/proc_fs.h>
+#include <linux/seq_file.h>
+#include <linux/bootconfig.h>
+#include <linux/slab.h>
+
+static char *saved_boot_config;
+
+static int boot_config_proc_show(struct seq_file *m, void *v)
+{
+	if (saved_boot_config)
+		seq_puts(m, saved_boot_config);
+	return 0;
+}
+
+/* Rest size of buffer */
+#define rest(dst, end) ((end) > (dst) ? (end) - (dst) : 0)
+
+/* Return the needed total length if @size is 0 */
+static int __init copy_xbc_key_value_list(char *dst, size_t size)
+{
+	struct xbc_node *leaf, *vnode;
+	char *key, *end = dst + size;
+	const char *val;
+	char q;
+	int ret = 0;
+
+	key = kzalloc(XBC_KEYLEN_MAX, GFP_KERNEL);
+	if (!key)
+		return -ENOMEM;
+
+	xbc_for_each_key_value(leaf, val) {
+		ret = xbc_node_compose_key(leaf, key, XBC_KEYLEN_MAX);
+		if (ret < 0)
+			break;
+		ret = snprintf(dst, rest(dst, end), "%s = ", key);
+		if (ret < 0)
+			break;
+		dst += ret;
+		vnode = xbc_node_get_child(leaf);
+		if (vnode) {
+			xbc_array_for_each_value(vnode, val) {
+				if (strchr(val, '"'))
+					q = '\'';
+				else
+					q = '"';
+				ret = snprintf(dst, rest(dst, end), "%c%s%c%s",
+					q, val, q, xbc_node_is_array(vnode) ? ", " : "\n");
+				if (ret < 0)
+					goto out;
+				dst += ret;
+			}
+		} else {
+			ret = snprintf(dst, rest(dst, end), "\"\"\n");
+			if (ret < 0)
+				break;
+			dst += ret;
+		}
+	}
+out:
+	kfree(key);
+
+	return ret < 0 ? ret : dst - (end - size);
+}
+
+static int __init proc_boot_config_init(void)
+{
+	int len;
+
+	len = copy_xbc_key_value_list(NULL, 0);
+	if (len < 0)
+		return len;
+
+	if (len > 0) {
+		saved_boot_config = kzalloc(len + 1, GFP_KERNEL);
+		if (!saved_boot_config)
+			return -ENOMEM;
+
+		len = copy_xbc_key_value_list(saved_boot_config, len + 1);
+		if (len < 0) {
+			kfree(saved_boot_config);
+			return len;
+		}
+	}
+
+	proc_create_single("bootconfig", 0, NULL, boot_config_proc_show);
+
+	return 0;
+}
+fs_initcall(proc_boot_config_init);
diff --git a/fs/proc/cmdline.c b/fs/proc/cmdline.c
new file mode 100644
index 000000000..fa762c5fb
--- /dev/null
+++ b/fs/proc/cmdline.c
@@ -0,0 +1,19 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/fs.h>
+#include <linux/init.h>
+#include <linux/proc_fs.h>
+#include <linux/seq_file.h>
+
+static int cmdline_proc_show(struct seq_file *m, void *v)
+{
+	seq_puts(m, saved_command_line);
+	seq_putc(m, '\n');
+	return 0;
+}
+
+static int __init proc_cmdline_init(void)
+{
+	proc_create_single("cmdline", 0, NULL, cmdline_proc_show);
+	return 0;
+}
+fs_initcall(proc_cmdline_init);
diff --git a/fs/proc/consoles.c b/fs/proc/consoles.c
new file mode 100644
index 000000000..dfe6ce350
--- /dev/null
+++ b/fs/proc/consoles.c
@@ -0,0 +1,98 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (c) 2010 Werner Fink, Jiri Slaby
+ */
+
+#include <linux/console.h>
+#include <linux/kernel.h>
+#include <linux/proc_fs.h>
+#include <linux/seq_file.h>
+#include <linux/tty_driver.h>
+
+/*
+ * This is handler for /proc/consoles
+ */
+static int show_console_dev(struct seq_file *m, void *v)
+{
+	static const struct {
+		short flag;
+		char name;
+	} con_flags[] = {
+		{ CON_ENABLED,		'E' },
+		{ CON_CONSDEV,		'C' },
+		{ CON_BOOT,		'B' },
+		{ CON_PRINTBUFFER,	'p' },
+		{ CON_BRL,		'b' },
+		{ CON_ANYTIME,		'a' },
+	};
+	char flags[ARRAY_SIZE(con_flags) + 1];
+	struct console *con = v;
+	unsigned int a;
+	dev_t dev = 0;
+
+	if (con->device) {
+		const struct tty_driver *driver;
+		int index;
+		driver = con->device(con, &index);
+		if (driver) {
+			dev = MKDEV(driver->major, driver->minor_start);
+			dev += index;
+		}
+	}
+
+	for (a = 0; a < ARRAY_SIZE(con_flags); a++)
+		flags[a] = (con->flags & con_flags[a].flag) ?
+			con_flags[a].name : ' ';
+	flags[a] = 0;
+
+	seq_setwidth(m, 21 - 1);
+	seq_printf(m, "%s%d", con->name, con->index);
+	seq_pad(m, ' ');
+	seq_printf(m, "%c%c%c (%s)", con->read ? 'R' : '-',
+			con->write ? 'W' : '-', con->unblank ? 'U' : '-',
+			flags);
+	if (dev)
+		seq_printf(m, " %4d:%d", MAJOR(dev), MINOR(dev));
+
+	seq_putc(m, '\n');
+	return 0;
+}
+
+static void *c_start(struct seq_file *m, loff_t *pos)
+{
+	struct console *con;
+	loff_t off = 0;
+
+	console_lock();
+	for_each_console(con)
+		if (off++ == *pos)
+			break;
+
+	return con;
+}
+
+static void *c_next(struct seq_file *m, void *v, loff_t *pos)
+{
+	struct console *con = v;
+	++*pos;
+	return con->next;
+}
+
+static void c_stop(struct seq_file *m, void *v)
+{
+	console_unlock();
+}
+
+static const struct seq_operations consoles_op = {
+	.start	= c_start,
+	.next	= c_next,
+	.stop	= c_stop,
+	.show	= show_console_dev
+};
+
+static int __init proc_consoles_init(void)
+{
+	proc_create_seq("consoles", 0, NULL, &consoles_op);
+	return 0;
+}
+fs_initcall(proc_consoles_init);
diff --git a/fs/proc/cpuinfo.c b/fs/proc/cpuinfo.c
new file mode 100644
index 000000000..f38bda5b8
--- /dev/null
+++ b/fs/proc/cpuinfo.c
@@ -0,0 +1,28 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/cpufreq.h>
+#include <linux/fs.h>
+#include <linux/init.h>
+#include <linux/proc_fs.h>
+#include <linux/seq_file.h>
+
+extern const struct seq_operations cpuinfo_op;
+
+static int cpuinfo_open(struct inode *inode, struct file *file)
+{
+	return seq_open(file, &cpuinfo_op);
+}
+
+static const struct proc_ops cpuinfo_proc_ops = {
+	.proc_flags	= PROC_ENTRY_PERMANENT,
+	.proc_open	= cpuinfo_open,
+	.proc_read_iter	= seq_read_iter,
+	.proc_lseek	= seq_lseek,
+	.proc_release	= seq_release,
+};
+
+static int __init proc_cpuinfo_init(void)
+{
+	proc_create("cpuinfo", 0, NULL, &cpuinfo_proc_ops);
+	return 0;
+}
+fs_initcall(proc_cpuinfo_init);
diff --git a/fs/proc/devices.c b/fs/proc/devices.c
new file mode 100644
index 000000000..fe7bfcb7d
--- /dev/null
+++ b/fs/proc/devices.c
@@ -0,0 +1,64 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/fs.h>
+#include <linux/init.h>
+#include <linux/proc_fs.h>
+#include <linux/seq_file.h>
+#include <linux/blkdev.h>
+#include "internal.h"
+
+static int devinfo_show(struct seq_file *f, void *v)
+{
+	int i = *(loff_t *) v;
+
+	if (i < CHRDEV_MAJOR_MAX) {
+		if (i == 0)
+			seq_puts(f, "Character devices:\n");
+		chrdev_show(f, i);
+	}
+#ifdef CONFIG_BLOCK
+	else {
+		i -= CHRDEV_MAJOR_MAX;
+		if (i == 0)
+			seq_puts(f, "\nBlock devices:\n");
+		blkdev_show(f, i);
+	}
+#endif
+	return 0;
+}
+
+static void *devinfo_start(struct seq_file *f, loff_t *pos)
+{
+	if (*pos < (BLKDEV_MAJOR_MAX + CHRDEV_MAJOR_MAX))
+		return pos;
+	return NULL;
+}
+
+static void *devinfo_next(struct seq_file *f, void *v, loff_t *pos)
+{
+	(*pos)++;
+	if (*pos >= (BLKDEV_MAJOR_MAX + CHRDEV_MAJOR_MAX))
+		return NULL;
+	return pos;
+}
+
+static void devinfo_stop(struct seq_file *f, void *v)
+{
+	/* Nothing to do */
+}
+
+static const struct seq_operations devinfo_ops = {
+	.start = devinfo_start,
+	.next  = devinfo_next,
+	.stop  = devinfo_stop,
+	.show  = devinfo_show
+};
+
+static int __init proc_devices_init(void)
+{
+	struct proc_dir_entry *pde;
+
+	pde = proc_create_seq("devices", 0, NULL, &devinfo_ops);
+	pde_make_permanent(pde);
+	return 0;
+}
+fs_initcall(proc_devices_init);
diff --git a/fs/proc/fd.c b/fs/proc/fd.c
new file mode 100644
index 000000000..913bef0d2
--- /dev/null
+++ b/fs/proc/fd.c
@@ -0,0 +1,381 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/sched/signal.h>
+#include <linux/errno.h>
+#include <linux/dcache.h>
+#include <linux/path.h>
+#include <linux/fdtable.h>
+#include <linux/namei.h>
+#include <linux/pid.h>
+#include <linux/ptrace.h>
+#include <linux/security.h>
+#include <linux/file.h>
+#include <linux/seq_file.h>
+#include <linux/fs.h>
+
+#include <linux/proc_fs.h>
+
+#include "../mount.h"
+#include "internal.h"
+#include "fd.h"
+
+static int seq_show(struct seq_file *m, void *v)
+{
+	struct files_struct *files = NULL;
+	int f_flags = 0, ret = -ENOENT;
+	struct file *file = NULL;
+	struct task_struct *task;
+
+	task = get_proc_task(m->private);
+	if (!task)
+		return -ENOENT;
+
+	task_lock(task);
+	files = task->files;
+	if (files) {
+		unsigned int fd = proc_fd(m->private);
+
+		spin_lock(&files->file_lock);
+		file = files_lookup_fd_locked(files, fd);
+		if (file) {
+			struct fdtable *fdt = files_fdtable(files);
+
+			f_flags = file->f_flags;
+			if (close_on_exec(fd, fdt))
+				f_flags |= O_CLOEXEC;
+
+			get_file(file);
+			ret = 0;
+		}
+		spin_unlock(&files->file_lock);
+	}
+	task_unlock(task);
+	put_task_struct(task);
+
+	if (ret)
+		return ret;
+
+	seq_printf(m, "pos:\t%lli\nflags:\t0%o\nmnt_id:\t%i\nino:\t%lu\n",
+		   (long long)file->f_pos, f_flags,
+		   real_mount(file->f_path.mnt)->mnt_id,
+		   file_inode(file)->i_ino);
+
+	/* show_fd_locks() never deferences files so a stale value is safe */
+	show_fd_locks(m, file, files);
+	if (seq_has_overflowed(m))
+		goto out;
+
+	if (file->f_op->show_fdinfo)
+		file->f_op->show_fdinfo(m, file);
+
+out:
+	fput(file);
+	return 0;
+}
+
+static int proc_fdinfo_access_allowed(struct inode *inode)
+{
+	bool allowed = false;
+	struct task_struct *task = get_proc_task(inode);
+
+	if (!task)
+		return -ESRCH;
+
+	allowed = ptrace_may_access(task, PTRACE_MODE_READ_FSCREDS);
+	put_task_struct(task);
+
+	if (!allowed)
+		return -EACCES;
+
+	return 0;
+}
+
+static int seq_fdinfo_open(struct inode *inode, struct file *file)
+{
+	int ret = proc_fdinfo_access_allowed(inode);
+
+	if (ret)
+		return ret;
+
+	return single_open(file, seq_show, inode);
+}
+
+static const struct file_operations proc_fdinfo_file_operations = {
+	.open		= seq_fdinfo_open,
+	.read		= seq_read,
+	.llseek		= seq_lseek,
+	.release	= single_release,
+};
+
+static bool tid_fd_mode(struct task_struct *task, unsigned fd, fmode_t *mode)
+{
+	struct file *file;
+
+	rcu_read_lock();
+	file = task_lookup_fd_rcu(task, fd);
+	if (file)
+		*mode = file->f_mode;
+	rcu_read_unlock();
+	return !!file;
+}
+
+static void tid_fd_update_inode(struct task_struct *task, struct inode *inode,
+				fmode_t f_mode)
+{
+	task_dump_owner(task, 0, &inode->i_uid, &inode->i_gid);
+
+	if (S_ISLNK(inode->i_mode)) {
+		unsigned i_mode = S_IFLNK;
+		if (f_mode & FMODE_READ)
+			i_mode |= S_IRUSR | S_IXUSR;
+		if (f_mode & FMODE_WRITE)
+			i_mode |= S_IWUSR | S_IXUSR;
+		inode->i_mode = i_mode;
+	}
+	security_task_to_inode(task, inode);
+}
+
+static int tid_fd_revalidate(struct dentry *dentry, unsigned int flags)
+{
+	struct task_struct *task;
+	struct inode *inode;
+	unsigned int fd;
+
+	if (flags & LOOKUP_RCU)
+		return -ECHILD;
+
+	inode = d_inode(dentry);
+	task = get_proc_task(inode);
+	fd = proc_fd(inode);
+
+	if (task) {
+		fmode_t f_mode;
+		if (tid_fd_mode(task, fd, &f_mode)) {
+			tid_fd_update_inode(task, inode, f_mode);
+			put_task_struct(task);
+			return 1;
+		}
+		put_task_struct(task);
+	}
+	return 0;
+}
+
+static const struct dentry_operations tid_fd_dentry_operations = {
+	.d_revalidate	= tid_fd_revalidate,
+	.d_delete	= pid_delete_dentry,
+};
+
+static int proc_fd_link(struct dentry *dentry, struct path *path)
+{
+	struct task_struct *task;
+	int ret = -ENOENT;
+
+	task = get_proc_task(d_inode(dentry));
+	if (task) {
+		unsigned int fd = proc_fd(d_inode(dentry));
+		struct file *fd_file;
+
+		fd_file = fget_task(task, fd);
+		if (fd_file) {
+			*path = fd_file->f_path;
+			path_get(&fd_file->f_path);
+			ret = 0;
+			fput(fd_file);
+		}
+		put_task_struct(task);
+	}
+
+	return ret;
+}
+
+struct fd_data {
+	fmode_t mode;
+	unsigned fd;
+};
+
+static struct dentry *proc_fd_instantiate(struct dentry *dentry,
+	struct task_struct *task, const void *ptr)
+{
+	const struct fd_data *data = ptr;
+	struct proc_inode *ei;
+	struct inode *inode;
+
+	inode = proc_pid_make_inode(dentry->d_sb, task, S_IFLNK);
+	if (!inode)
+		return ERR_PTR(-ENOENT);
+
+	ei = PROC_I(inode);
+	ei->fd = data->fd;
+
+	inode->i_op = &proc_pid_link_inode_operations;
+	inode->i_size = 64;
+
+	ei->op.proc_get_link = proc_fd_link;
+	tid_fd_update_inode(task, inode, data->mode);
+
+	d_set_d_op(dentry, &tid_fd_dentry_operations);
+	return d_splice_alias(inode, dentry);
+}
+
+static struct dentry *proc_lookupfd_common(struct inode *dir,
+					   struct dentry *dentry,
+					   instantiate_t instantiate)
+{
+	struct task_struct *task = get_proc_task(dir);
+	struct fd_data data = {.fd = name_to_int(&dentry->d_name)};
+	struct dentry *result = ERR_PTR(-ENOENT);
+
+	if (!task)
+		goto out_no_task;
+	if (data.fd == ~0U)
+		goto out;
+	if (!tid_fd_mode(task, data.fd, &data.mode))
+		goto out;
+
+	result = instantiate(dentry, task, &data);
+out:
+	put_task_struct(task);
+out_no_task:
+	return result;
+}
+
+static int proc_readfd_common(struct file *file, struct dir_context *ctx,
+			      instantiate_t instantiate)
+{
+	struct task_struct *p = get_proc_task(file_inode(file));
+	unsigned int fd;
+
+	if (!p)
+		return -ENOENT;
+
+	if (!dir_emit_dots(file, ctx))
+		goto out;
+
+	rcu_read_lock();
+	for (fd = ctx->pos - 2;; fd++) {
+		struct file *f;
+		struct fd_data data;
+		char name[10 + 1];
+		unsigned int len;
+
+		f = task_lookup_next_fd_rcu(p, &fd);
+		ctx->pos = fd + 2LL;
+		if (!f)
+			break;
+		data.mode = f->f_mode;
+		rcu_read_unlock();
+		data.fd = fd;
+
+		len = snprintf(name, sizeof(name), "%u", fd);
+		if (!proc_fill_cache(file, ctx,
+				     name, len, instantiate, p,
+				     &data))
+			goto out;
+		cond_resched();
+		rcu_read_lock();
+	}
+	rcu_read_unlock();
+out:
+	put_task_struct(p);
+	return 0;
+}
+
+static int proc_readfd(struct file *file, struct dir_context *ctx)
+{
+	return proc_readfd_common(file, ctx, proc_fd_instantiate);
+}
+
+const struct file_operations proc_fd_operations = {
+	.read		= generic_read_dir,
+	.iterate_shared	= proc_readfd,
+	.llseek		= generic_file_llseek,
+};
+
+static struct dentry *proc_lookupfd(struct inode *dir, struct dentry *dentry,
+				    unsigned int flags)
+{
+	return proc_lookupfd_common(dir, dentry, proc_fd_instantiate);
+}
+
+/*
+ * /proc/pid/fd needs a special permission handler so that a process can still
+ * access /proc/self/fd after it has executed a setuid().
+ */
+int proc_fd_permission(struct user_namespace *mnt_userns,
+		       struct inode *inode, int mask)
+{
+	struct task_struct *p;
+	int rv;
+
+	rv = generic_permission(&init_user_ns, inode, mask);
+	if (rv == 0)
+		return rv;
+
+	rcu_read_lock();
+	p = pid_task(proc_pid(inode), PIDTYPE_PID);
+	if (p && same_thread_group(p, current))
+		rv = 0;
+	rcu_read_unlock();
+
+	return rv;
+}
+
+const struct inode_operations proc_fd_inode_operations = {
+	.lookup		= proc_lookupfd,
+	.permission	= proc_fd_permission,
+	.setattr	= proc_setattr,
+};
+
+static struct dentry *proc_fdinfo_instantiate(struct dentry *dentry,
+	struct task_struct *task, const void *ptr)
+{
+	const struct fd_data *data = ptr;
+	struct proc_inode *ei;
+	struct inode *inode;
+
+	inode = proc_pid_make_inode(dentry->d_sb, task, S_IFREG | S_IRUGO);
+	if (!inode)
+		return ERR_PTR(-ENOENT);
+
+	ei = PROC_I(inode);
+	ei->fd = data->fd;
+
+	inode->i_fop = &proc_fdinfo_file_operations;
+	tid_fd_update_inode(task, inode, 0);
+
+	d_set_d_op(dentry, &tid_fd_dentry_operations);
+	return d_splice_alias(inode, dentry);
+}
+
+static struct dentry *
+proc_lookupfdinfo(struct inode *dir, struct dentry *dentry, unsigned int flags)
+{
+	return proc_lookupfd_common(dir, dentry, proc_fdinfo_instantiate);
+}
+
+static int proc_readfdinfo(struct file *file, struct dir_context *ctx)
+{
+	return proc_readfd_common(file, ctx,
+				  proc_fdinfo_instantiate);
+}
+
+static int proc_open_fdinfo(struct inode *inode, struct file *file)
+{
+	int ret = proc_fdinfo_access_allowed(inode);
+
+	if (ret)
+		return ret;
+
+	return 0;
+}
+
+const struct inode_operations proc_fdinfo_inode_operations = {
+	.lookup		= proc_lookupfdinfo,
+	.setattr	= proc_setattr,
+};
+
+const struct file_operations proc_fdinfo_operations = {
+	.open		= proc_open_fdinfo,
+	.read		= generic_read_dir,
+	.iterate_shared	= proc_readfdinfo,
+	.llseek		= generic_file_llseek,
+};
diff --git a/fs/proc/fd.h b/fs/proc/fd.h
new file mode 100644
index 000000000..c5a921a06
--- /dev/null
+++ b/fs/proc/fd.h
@@ -0,0 +1,21 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __PROCFS_FD_H__
+#define __PROCFS_FD_H__
+
+#include <linux/fs.h>
+
+extern const struct file_operations proc_fd_operations;
+extern const struct inode_operations proc_fd_inode_operations;
+
+extern const struct file_operations proc_fdinfo_operations;
+extern const struct inode_operations proc_fdinfo_inode_operations;
+
+extern int proc_fd_permission(struct user_namespace *mnt_userns,
+			      struct inode *inode, int mask);
+
+static inline unsigned int proc_fd(struct inode *inode)
+{
+	return PROC_I(inode)->fd;
+}
+
+#endif /* __PROCFS_FD_H__ */
diff --git a/fs/proc/generic.c b/fs/proc/generic.c
new file mode 100644
index 000000000..587b91d9d
--- /dev/null
+++ b/fs/proc/generic.c
@@ -0,0 +1,819 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * proc/fs/generic.c --- generic routines for the proc-fs
+ *
+ * This file contains generic proc-fs routines for handling
+ * directories and files.
+ * 
+ * Copyright (C) 1991, 1992 Linus Torvalds.
+ * Copyright (C) 1997 Theodore Ts'o
+ */
+
+#include <linux/cache.h>
+#include <linux/errno.h>
+#include <linux/time.h>
+#include <linux/proc_fs.h>
+#include <linux/stat.h>
+#include <linux/mm.h>
+#include <linux/module.h>
+#include <linux/namei.h>
+#include <linux/slab.h>
+#include <linux/printk.h>
+#include <linux/mount.h>
+#include <linux/init.h>
+#include <linux/idr.h>
+#include <linux/bitops.h>
+#include <linux/spinlock.h>
+#include <linux/completion.h>
+#include <linux/uaccess.h>
+#include <linux/seq_file.h>
+
+#include "internal.h"
+
+static DEFINE_RWLOCK(proc_subdir_lock);
+
+struct kmem_cache *proc_dir_entry_cache __ro_after_init;
+
+void pde_free(struct proc_dir_entry *pde)
+{
+	if (S_ISLNK(pde->mode))
+		kfree(pde->data);
+	if (pde->name != pde->inline_name)
+		kfree(pde->name);
+	kmem_cache_free(proc_dir_entry_cache, pde);
+}
+
+static int proc_match(const char *name, struct proc_dir_entry *de, unsigned int len)
+{
+	if (len < de->namelen)
+		return -1;
+	if (len > de->namelen)
+		return 1;
+
+	return memcmp(name, de->name, len);
+}
+
+static struct proc_dir_entry *pde_subdir_first(struct proc_dir_entry *dir)
+{
+	return rb_entry_safe(rb_first(&dir->subdir), struct proc_dir_entry,
+			     subdir_node);
+}
+
+static struct proc_dir_entry *pde_subdir_next(struct proc_dir_entry *dir)
+{
+	return rb_entry_safe(rb_next(&dir->subdir_node), struct proc_dir_entry,
+			     subdir_node);
+}
+
+static struct proc_dir_entry *pde_subdir_find(struct proc_dir_entry *dir,
+					      const char *name,
+					      unsigned int len)
+{
+	struct rb_node *node = dir->subdir.rb_node;
+
+	while (node) {
+		struct proc_dir_entry *de = rb_entry(node,
+						     struct proc_dir_entry,
+						     subdir_node);
+		int result = proc_match(name, de, len);
+
+		if (result < 0)
+			node = node->rb_left;
+		else if (result > 0)
+			node = node->rb_right;
+		else
+			return de;
+	}
+	return NULL;
+}
+
+static bool pde_subdir_insert(struct proc_dir_entry *dir,
+			      struct proc_dir_entry *de)
+{
+	struct rb_root *root = &dir->subdir;
+	struct rb_node **new = &root->rb_node, *parent = NULL;
+
+	/* Figure out where to put new node */
+	while (*new) {
+		struct proc_dir_entry *this = rb_entry(*new,
+						       struct proc_dir_entry,
+						       subdir_node);
+		int result = proc_match(de->name, this, de->namelen);
+
+		parent = *new;
+		if (result < 0)
+			new = &(*new)->rb_left;
+		else if (result > 0)
+			new = &(*new)->rb_right;
+		else
+			return false;
+	}
+
+	/* Add new node and rebalance tree. */
+	rb_link_node(&de->subdir_node, parent, new);
+	rb_insert_color(&de->subdir_node, root);
+	return true;
+}
+
+static int proc_notify_change(struct user_namespace *mnt_userns,
+			      struct dentry *dentry, struct iattr *iattr)
+{
+	struct inode *inode = d_inode(dentry);
+	struct proc_dir_entry *de = PDE(inode);
+	int error;
+
+	error = setattr_prepare(&init_user_ns, dentry, iattr);
+	if (error)
+		return error;
+
+	setattr_copy(&init_user_ns, inode, iattr);
+	mark_inode_dirty(inode);
+
+	proc_set_user(de, inode->i_uid, inode->i_gid);
+	de->mode = inode->i_mode;
+	return 0;
+}
+
+static int proc_getattr(struct user_namespace *mnt_userns,
+			const struct path *path, struct kstat *stat,
+			u32 request_mask, unsigned int query_flags)
+{
+	struct inode *inode = d_inode(path->dentry);
+	struct proc_dir_entry *de = PDE(inode);
+	if (de) {
+		nlink_t nlink = READ_ONCE(de->nlink);
+		if (nlink > 0) {
+			set_nlink(inode, nlink);
+		}
+	}
+
+	generic_fillattr(&init_user_ns, inode, stat);
+	return 0;
+}
+
+static const struct inode_operations proc_file_inode_operations = {
+	.setattr	= proc_notify_change,
+};
+
+/*
+ * This function parses a name such as "tty/driver/serial", and
+ * returns the struct proc_dir_entry for "/proc/tty/driver", and
+ * returns "serial" in residual.
+ */
+static int __xlate_proc_name(const char *name, struct proc_dir_entry **ret,
+			     const char **residual)
+{
+	const char     		*cp = name, *next;
+	struct proc_dir_entry	*de;
+
+	de = *ret ?: &proc_root;
+	while ((next = strchr(cp, '/')) != NULL) {
+		de = pde_subdir_find(de, cp, next - cp);
+		if (!de) {
+			WARN(1, "name '%s'\n", name);
+			return -ENOENT;
+		}
+		cp = next + 1;
+	}
+	*residual = cp;
+	*ret = de;
+	return 0;
+}
+
+static int xlate_proc_name(const char *name, struct proc_dir_entry **ret,
+			   const char **residual)
+{
+	int rv;
+
+	read_lock(&proc_subdir_lock);
+	rv = __xlate_proc_name(name, ret, residual);
+	read_unlock(&proc_subdir_lock);
+	return rv;
+}
+
+static DEFINE_IDA(proc_inum_ida);
+
+#define PROC_DYNAMIC_FIRST 0xF0000000U
+
+/*
+ * Return an inode number between PROC_DYNAMIC_FIRST and
+ * 0xffffffff, or zero on failure.
+ */
+int proc_alloc_inum(unsigned int *inum)
+{
+	int i;
+
+	i = ida_simple_get(&proc_inum_ida, 0, UINT_MAX - PROC_DYNAMIC_FIRST + 1,
+			   GFP_KERNEL);
+	if (i < 0)
+		return i;
+
+	*inum = PROC_DYNAMIC_FIRST + (unsigned int)i;
+	return 0;
+}
+
+void proc_free_inum(unsigned int inum)
+{
+	ida_simple_remove(&proc_inum_ida, inum - PROC_DYNAMIC_FIRST);
+}
+
+static int proc_misc_d_revalidate(struct dentry *dentry, unsigned int flags)
+{
+	if (flags & LOOKUP_RCU)
+		return -ECHILD;
+
+	if (atomic_read(&PDE(d_inode(dentry))->in_use) < 0)
+		return 0; /* revalidate */
+	return 1;
+}
+
+static int proc_misc_d_delete(const struct dentry *dentry)
+{
+	return atomic_read(&PDE(d_inode(dentry))->in_use) < 0;
+}
+
+static const struct dentry_operations proc_misc_dentry_ops = {
+	.d_revalidate	= proc_misc_d_revalidate,
+	.d_delete	= proc_misc_d_delete,
+};
+
+/*
+ * Don't create negative dentries here, return -ENOENT by hand
+ * instead.
+ */
+struct dentry *proc_lookup_de(struct inode *dir, struct dentry *dentry,
+			      struct proc_dir_entry *de)
+{
+	struct inode *inode;
+
+	read_lock(&proc_subdir_lock);
+	de = pde_subdir_find(de, dentry->d_name.name, dentry->d_name.len);
+	if (de) {
+		pde_get(de);
+		read_unlock(&proc_subdir_lock);
+		inode = proc_get_inode(dir->i_sb, de);
+		if (!inode)
+			return ERR_PTR(-ENOMEM);
+		d_set_d_op(dentry, de->proc_dops);
+		return d_splice_alias(inode, dentry);
+	}
+	read_unlock(&proc_subdir_lock);
+	return ERR_PTR(-ENOENT);
+}
+
+struct dentry *proc_lookup(struct inode *dir, struct dentry *dentry,
+		unsigned int flags)
+{
+	struct proc_fs_info *fs_info = proc_sb_info(dir->i_sb);
+
+	if (fs_info->pidonly == PROC_PIDONLY_ON)
+		return ERR_PTR(-ENOENT);
+
+	return proc_lookup_de(dir, dentry, PDE(dir));
+}
+
+/*
+ * This returns non-zero if at EOF, so that the /proc
+ * root directory can use this and check if it should
+ * continue with the <pid> entries..
+ *
+ * Note that the VFS-layer doesn't care about the return
+ * value of the readdir() call, as long as it's non-negative
+ * for success..
+ */
+int proc_readdir_de(struct file *file, struct dir_context *ctx,
+		    struct proc_dir_entry *de)
+{
+	int i;
+
+	if (!dir_emit_dots(file, ctx))
+		return 0;
+
+	i = ctx->pos - 2;
+	read_lock(&proc_subdir_lock);
+	de = pde_subdir_first(de);
+	for (;;) {
+		if (!de) {
+			read_unlock(&proc_subdir_lock);
+			return 0;
+		}
+		if (!i)
+			break;
+		de = pde_subdir_next(de);
+		i--;
+	}
+
+	do {
+		struct proc_dir_entry *next;
+		pde_get(de);
+		read_unlock(&proc_subdir_lock);
+		if (!dir_emit(ctx, de->name, de->namelen,
+			    de->low_ino, de->mode >> 12)) {
+			pde_put(de);
+			return 0;
+		}
+		ctx->pos++;
+		read_lock(&proc_subdir_lock);
+		next = pde_subdir_next(de);
+		pde_put(de);
+		de = next;
+	} while (de);
+	read_unlock(&proc_subdir_lock);
+	return 1;
+}
+
+int proc_readdir(struct file *file, struct dir_context *ctx)
+{
+	struct inode *inode = file_inode(file);
+	struct proc_fs_info *fs_info = proc_sb_info(inode->i_sb);
+
+	if (fs_info->pidonly == PROC_PIDONLY_ON)
+		return 1;
+
+	return proc_readdir_de(file, ctx, PDE(inode));
+}
+
+/*
+ * These are the generic /proc directory operations. They
+ * use the in-memory "struct proc_dir_entry" tree to parse
+ * the /proc directory.
+ */
+static const struct file_operations proc_dir_operations = {
+	.llseek			= generic_file_llseek,
+	.read			= generic_read_dir,
+	.iterate_shared		= proc_readdir,
+};
+
+static int proc_net_d_revalidate(struct dentry *dentry, unsigned int flags)
+{
+	return 0;
+}
+
+const struct dentry_operations proc_net_dentry_ops = {
+	.d_revalidate	= proc_net_d_revalidate,
+	.d_delete	= always_delete_dentry,
+};
+
+/*
+ * proc directories can do almost nothing..
+ */
+static const struct inode_operations proc_dir_inode_operations = {
+	.lookup		= proc_lookup,
+	.getattr	= proc_getattr,
+	.setattr	= proc_notify_change,
+};
+
+/* returns the registered entry, or frees dp and returns NULL on failure */
+struct proc_dir_entry *proc_register(struct proc_dir_entry *dir,
+		struct proc_dir_entry *dp)
+{
+	if (proc_alloc_inum(&dp->low_ino))
+		goto out_free_entry;
+
+	write_lock(&proc_subdir_lock);
+	dp->parent = dir;
+	if (pde_subdir_insert(dir, dp) == false) {
+		WARN(1, "proc_dir_entry '%s/%s' already registered\n",
+		     dir->name, dp->name);
+		write_unlock(&proc_subdir_lock);
+		goto out_free_inum;
+	}
+	dir->nlink++;
+	write_unlock(&proc_subdir_lock);
+
+	return dp;
+out_free_inum:
+	proc_free_inum(dp->low_ino);
+out_free_entry:
+	pde_free(dp);
+	return NULL;
+}
+
+static struct proc_dir_entry *__proc_create(struct proc_dir_entry **parent,
+					  const char *name,
+					  umode_t mode,
+					  nlink_t nlink)
+{
+	struct proc_dir_entry *ent = NULL;
+	const char *fn;
+	struct qstr qstr;
+
+	if (xlate_proc_name(name, parent, &fn) != 0)
+		goto out;
+	qstr.name = fn;
+	qstr.len = strlen(fn);
+	if (qstr.len == 0 || qstr.len >= 256) {
+		WARN(1, "name len %u\n", qstr.len);
+		return NULL;
+	}
+	if (qstr.len == 1 && fn[0] == '.') {
+		WARN(1, "name '.'\n");
+		return NULL;
+	}
+	if (qstr.len == 2 && fn[0] == '.' && fn[1] == '.') {
+		WARN(1, "name '..'\n");
+		return NULL;
+	}
+	if (*parent == &proc_root && name_to_int(&qstr) != ~0U) {
+		WARN(1, "create '/proc/%s' by hand\n", qstr.name);
+		return NULL;
+	}
+	if (is_empty_pde(*parent)) {
+		WARN(1, "attempt to add to permanently empty directory");
+		return NULL;
+	}
+
+	ent = kmem_cache_zalloc(proc_dir_entry_cache, GFP_KERNEL);
+	if (!ent)
+		goto out;
+
+	if (qstr.len + 1 <= SIZEOF_PDE_INLINE_NAME) {
+		ent->name = ent->inline_name;
+	} else {
+		ent->name = kmalloc(qstr.len + 1, GFP_KERNEL);
+		if (!ent->name) {
+			pde_free(ent);
+			return NULL;
+		}
+	}
+
+	memcpy(ent->name, fn, qstr.len + 1);
+	ent->namelen = qstr.len;
+	ent->mode = mode;
+	ent->nlink = nlink;
+	ent->subdir = RB_ROOT;
+	refcount_set(&ent->refcnt, 1);
+	spin_lock_init(&ent->pde_unload_lock);
+	INIT_LIST_HEAD(&ent->pde_openers);
+	proc_set_user(ent, (*parent)->uid, (*parent)->gid);
+
+	ent->proc_dops = &proc_misc_dentry_ops;
+	/* Revalidate everything under /proc/${pid}/net */
+	if ((*parent)->proc_dops == &proc_net_dentry_ops)
+		pde_force_lookup(ent);
+
+out:
+	return ent;
+}
+
+struct proc_dir_entry *proc_symlink(const char *name,
+		struct proc_dir_entry *parent, const char *dest)
+{
+	struct proc_dir_entry *ent;
+
+	ent = __proc_create(&parent, name,
+			  (S_IFLNK | S_IRUGO | S_IWUGO | S_IXUGO),1);
+
+	if (ent) {
+		ent->data = kmalloc((ent->size=strlen(dest))+1, GFP_KERNEL);
+		if (ent->data) {
+			strcpy((char*)ent->data,dest);
+			ent->proc_iops = &proc_link_inode_operations;
+			ent = proc_register(parent, ent);
+		} else {
+			pde_free(ent);
+			ent = NULL;
+		}
+	}
+	return ent;
+}
+EXPORT_SYMBOL(proc_symlink);
+
+struct proc_dir_entry *_proc_mkdir(const char *name, umode_t mode,
+		struct proc_dir_entry *parent, void *data, bool force_lookup)
+{
+	struct proc_dir_entry *ent;
+
+	if (mode == 0)
+		mode = S_IRUGO | S_IXUGO;
+
+	ent = __proc_create(&parent, name, S_IFDIR | mode, 2);
+	if (ent) {
+		ent->data = data;
+		ent->proc_dir_ops = &proc_dir_operations;
+		ent->proc_iops = &proc_dir_inode_operations;
+		if (force_lookup) {
+			pde_force_lookup(ent);
+		}
+		ent = proc_register(parent, ent);
+	}
+	return ent;
+}
+EXPORT_SYMBOL_GPL(_proc_mkdir);
+
+struct proc_dir_entry *proc_mkdir_data(const char *name, umode_t mode,
+		struct proc_dir_entry *parent, void *data)
+{
+	return _proc_mkdir(name, mode, parent, data, false);
+}
+EXPORT_SYMBOL_GPL(proc_mkdir_data);
+
+struct proc_dir_entry *proc_mkdir_mode(const char *name, umode_t mode,
+				       struct proc_dir_entry *parent)
+{
+	return proc_mkdir_data(name, mode, parent, NULL);
+}
+EXPORT_SYMBOL(proc_mkdir_mode);
+
+struct proc_dir_entry *proc_mkdir(const char *name,
+		struct proc_dir_entry *parent)
+{
+	return proc_mkdir_data(name, 0, parent, NULL);
+}
+EXPORT_SYMBOL(proc_mkdir);
+
+struct proc_dir_entry *proc_create_mount_point(const char *name)
+{
+	umode_t mode = S_IFDIR | S_IRUGO | S_IXUGO;
+	struct proc_dir_entry *ent, *parent = NULL;
+
+	ent = __proc_create(&parent, name, mode, 2);
+	if (ent) {
+		ent->data = NULL;
+		ent->proc_dir_ops = NULL;
+		ent->proc_iops = NULL;
+		ent = proc_register(parent, ent);
+	}
+	return ent;
+}
+EXPORT_SYMBOL(proc_create_mount_point);
+
+struct proc_dir_entry *proc_create_reg(const char *name, umode_t mode,
+		struct proc_dir_entry **parent, void *data)
+{
+	struct proc_dir_entry *p;
+
+	if ((mode & S_IFMT) == 0)
+		mode |= S_IFREG;
+	if ((mode & S_IALLUGO) == 0)
+		mode |= S_IRUGO;
+	if (WARN_ON_ONCE(!S_ISREG(mode)))
+		return NULL;
+
+	p = __proc_create(parent, name, mode, 1);
+	if (p) {
+		p->proc_iops = &proc_file_inode_operations;
+		p->data = data;
+	}
+	return p;
+}
+
+static inline void pde_set_flags(struct proc_dir_entry *pde)
+{
+	if (pde->proc_ops->proc_flags & PROC_ENTRY_PERMANENT)
+		pde->flags |= PROC_ENTRY_PERMANENT;
+}
+
+struct proc_dir_entry *proc_create_data(const char *name, umode_t mode,
+		struct proc_dir_entry *parent,
+		const struct proc_ops *proc_ops, void *data)
+{
+	struct proc_dir_entry *p;
+
+	p = proc_create_reg(name, mode, &parent, data);
+	if (!p)
+		return NULL;
+	p->proc_ops = proc_ops;
+	pde_set_flags(p);
+	return proc_register(parent, p);
+}
+EXPORT_SYMBOL(proc_create_data);
+ 
+struct proc_dir_entry *proc_create(const char *name, umode_t mode,
+				   struct proc_dir_entry *parent,
+				   const struct proc_ops *proc_ops)
+{
+	return proc_create_data(name, mode, parent, proc_ops, NULL);
+}
+EXPORT_SYMBOL(proc_create);
+
+static int proc_seq_open(struct inode *inode, struct file *file)
+{
+	struct proc_dir_entry *de = PDE(inode);
+
+	if (de->state_size)
+		return seq_open_private(file, de->seq_ops, de->state_size);
+	return seq_open(file, de->seq_ops);
+}
+
+static int proc_seq_release(struct inode *inode, struct file *file)
+{
+	struct proc_dir_entry *de = PDE(inode);
+
+	if (de->state_size)
+		return seq_release_private(inode, file);
+	return seq_release(inode, file);
+}
+
+static const struct proc_ops proc_seq_ops = {
+	/* not permanent -- can call into arbitrary seq_operations */
+	.proc_open	= proc_seq_open,
+	.proc_read_iter	= seq_read_iter,
+	.proc_lseek	= seq_lseek,
+	.proc_release	= proc_seq_release,
+};
+
+struct proc_dir_entry *proc_create_seq_private(const char *name, umode_t mode,
+		struct proc_dir_entry *parent, const struct seq_operations *ops,
+		unsigned int state_size, void *data)
+{
+	struct proc_dir_entry *p;
+
+	p = proc_create_reg(name, mode, &parent, data);
+	if (!p)
+		return NULL;
+	p->proc_ops = &proc_seq_ops;
+	p->seq_ops = ops;
+	p->state_size = state_size;
+	return proc_register(parent, p);
+}
+EXPORT_SYMBOL(proc_create_seq_private);
+
+static int proc_single_open(struct inode *inode, struct file *file)
+{
+	struct proc_dir_entry *de = PDE(inode);
+
+	return single_open(file, de->single_show, de->data);
+}
+
+static const struct proc_ops proc_single_ops = {
+	/* not permanent -- can call into arbitrary ->single_show */
+	.proc_open	= proc_single_open,
+	.proc_read_iter = seq_read_iter,
+	.proc_lseek	= seq_lseek,
+	.proc_release	= single_release,
+};
+
+struct proc_dir_entry *proc_create_single_data(const char *name, umode_t mode,
+		struct proc_dir_entry *parent,
+		int (*show)(struct seq_file *, void *), void *data)
+{
+	struct proc_dir_entry *p;
+
+	p = proc_create_reg(name, mode, &parent, data);
+	if (!p)
+		return NULL;
+	p->proc_ops = &proc_single_ops;
+	p->single_show = show;
+	return proc_register(parent, p);
+}
+EXPORT_SYMBOL(proc_create_single_data);
+
+void proc_set_size(struct proc_dir_entry *de, loff_t size)
+{
+	de->size = size;
+}
+EXPORT_SYMBOL(proc_set_size);
+
+void proc_set_user(struct proc_dir_entry *de, kuid_t uid, kgid_t gid)
+{
+	de->uid = uid;
+	de->gid = gid;
+}
+EXPORT_SYMBOL(proc_set_user);
+
+void pde_put(struct proc_dir_entry *pde)
+{
+	if (refcount_dec_and_test(&pde->refcnt)) {
+		proc_free_inum(pde->low_ino);
+		pde_free(pde);
+	}
+}
+
+/*
+ * Remove a /proc entry and free it if it's not currently in use.
+ */
+void remove_proc_entry(const char *name, struct proc_dir_entry *parent)
+{
+	struct proc_dir_entry *de = NULL;
+	const char *fn = name;
+	unsigned int len;
+
+	write_lock(&proc_subdir_lock);
+	if (__xlate_proc_name(name, &parent, &fn) != 0) {
+		write_unlock(&proc_subdir_lock);
+		return;
+	}
+	len = strlen(fn);
+
+	de = pde_subdir_find(parent, fn, len);
+	if (de) {
+		if (unlikely(pde_is_permanent(de))) {
+			WARN(1, "removing permanent /proc entry '%s'", de->name);
+			de = NULL;
+		} else {
+			rb_erase(&de->subdir_node, &parent->subdir);
+			if (S_ISDIR(de->mode))
+				parent->nlink--;
+		}
+	}
+	write_unlock(&proc_subdir_lock);
+	if (!de) {
+		WARN(1, "name '%s'\n", name);
+		return;
+	}
+
+	proc_entry_rundown(de);
+
+	WARN(pde_subdir_first(de),
+	     "%s: removing non-empty directory '%s/%s', leaking at least '%s'\n",
+	     __func__, de->parent->name, de->name, pde_subdir_first(de)->name);
+	pde_put(de);
+}
+EXPORT_SYMBOL(remove_proc_entry);
+
+int remove_proc_subtree(const char *name, struct proc_dir_entry *parent)
+{
+	struct proc_dir_entry *root = NULL, *de, *next;
+	const char *fn = name;
+	unsigned int len;
+
+	write_lock(&proc_subdir_lock);
+	if (__xlate_proc_name(name, &parent, &fn) != 0) {
+		write_unlock(&proc_subdir_lock);
+		return -ENOENT;
+	}
+	len = strlen(fn);
+
+	root = pde_subdir_find(parent, fn, len);
+	if (!root) {
+		write_unlock(&proc_subdir_lock);
+		return -ENOENT;
+	}
+	if (unlikely(pde_is_permanent(root))) {
+		write_unlock(&proc_subdir_lock);
+		WARN(1, "removing permanent /proc entry '%s/%s'",
+			root->parent->name, root->name);
+		return -EINVAL;
+	}
+	rb_erase(&root->subdir_node, &parent->subdir);
+
+	de = root;
+	while (1) {
+		next = pde_subdir_first(de);
+		if (next) {
+			if (unlikely(pde_is_permanent(next))) {
+				write_unlock(&proc_subdir_lock);
+				WARN(1, "removing permanent /proc entry '%s/%s'",
+					next->parent->name, next->name);
+				return -EINVAL;
+			}
+			rb_erase(&next->subdir_node, &de->subdir);
+			de = next;
+			continue;
+		}
+		next = de->parent;
+		if (S_ISDIR(de->mode))
+			next->nlink--;
+		write_unlock(&proc_subdir_lock);
+
+		proc_entry_rundown(de);
+		if (de == root)
+			break;
+		pde_put(de);
+
+		write_lock(&proc_subdir_lock);
+		de = next;
+	}
+	pde_put(root);
+	return 0;
+}
+EXPORT_SYMBOL(remove_proc_subtree);
+
+void *proc_get_parent_data(const struct inode *inode)
+{
+	struct proc_dir_entry *de = PDE(inode);
+	return de->parent->data;
+}
+EXPORT_SYMBOL_GPL(proc_get_parent_data);
+
+void proc_remove(struct proc_dir_entry *de)
+{
+	if (de)
+		remove_proc_subtree(de->name, de->parent);
+}
+EXPORT_SYMBOL(proc_remove);
+
+/*
+ * Pull a user buffer into memory and pass it to the file's write handler if
+ * one is supplied.  The ->write() method is permitted to modify the
+ * kernel-side buffer.
+ */
+ssize_t proc_simple_write(struct file *f, const char __user *ubuf, size_t size,
+			  loff_t *_pos)
+{
+	struct proc_dir_entry *pde = PDE(file_inode(f));
+	char *buf;
+	int ret;
+
+	if (!pde->write)
+		return -EACCES;
+	if (size == 0 || size > PAGE_SIZE - 1)
+		return -EINVAL;
+	buf = memdup_user_nul(ubuf, size);
+	if (IS_ERR(buf))
+		return PTR_ERR(buf);
+	ret = pde->write(f, buf, size);
+	kfree(buf);
+	return ret == 0 ? size : ret;
+}
diff --git a/fs/proc/inode.c b/fs/proc/inode.c
new file mode 100644
index 000000000..f495fdb39
--- /dev/null
+++ b/fs/proc/inode.c
@@ -0,0 +1,704 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ *  linux/fs/proc/inode.c
+ *
+ *  Copyright (C) 1991, 1992  Linus Torvalds
+ */
+
+#include <linux/cache.h>
+#include <linux/time.h>
+#include <linux/proc_fs.h>
+#include <linux/kernel.h>
+#include <linux/pid_namespace.h>
+#include <linux/mm.h>
+#include <linux/string.h>
+#include <linux/stat.h>
+#include <linux/completion.h>
+#include <linux/poll.h>
+#include <linux/printk.h>
+#include <linux/file.h>
+#include <linux/limits.h>
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/sysctl.h>
+#include <linux/seq_file.h>
+#include <linux/slab.h>
+#include <linux/mount.h>
+#include <linux/bug.h>
+
+#include "internal.h"
+
+static void proc_evict_inode(struct inode *inode)
+{
+	struct proc_dir_entry *de;
+	struct ctl_table_header *head;
+	struct proc_inode *ei = PROC_I(inode);
+
+	truncate_inode_pages_final(&inode->i_data);
+	clear_inode(inode);
+
+	/* Stop tracking associated processes */
+	if (ei->pid) {
+		proc_pid_evict_inode(ei);
+		ei->pid = NULL;
+	}
+
+	/* Let go of any associated proc directory entry */
+	de = ei->pde;
+	if (de) {
+		pde_put(de);
+		ei->pde = NULL;
+	}
+
+	head = ei->sysctl;
+	if (head) {
+		RCU_INIT_POINTER(ei->sysctl, NULL);
+		proc_sys_evict_inode(inode, head);
+	}
+}
+
+static struct kmem_cache *proc_inode_cachep __ro_after_init;
+static struct kmem_cache *pde_opener_cache __ro_after_init;
+
+static struct inode *proc_alloc_inode(struct super_block *sb)
+{
+	struct proc_inode *ei;
+
+	ei = alloc_inode_sb(sb, proc_inode_cachep, GFP_KERNEL);
+	if (!ei)
+		return NULL;
+	ei->pid = NULL;
+	ei->fd = 0;
+	ei->op.proc_get_link = NULL;
+	ei->pde = NULL;
+	ei->sysctl = NULL;
+	ei->sysctl_entry = NULL;
+	INIT_HLIST_NODE(&ei->sibling_inodes);
+	ei->ns_ops = NULL;
+	return &ei->vfs_inode;
+}
+
+static void proc_free_inode(struct inode *inode)
+{
+	kmem_cache_free(proc_inode_cachep, PROC_I(inode));
+}
+
+static void init_once(void *foo)
+{
+	struct proc_inode *ei = (struct proc_inode *) foo;
+
+	inode_init_once(&ei->vfs_inode);
+}
+
+void __init proc_init_kmemcache(void)
+{
+	proc_inode_cachep = kmem_cache_create("proc_inode_cache",
+					     sizeof(struct proc_inode),
+					     0, (SLAB_RECLAIM_ACCOUNT|
+						SLAB_MEM_SPREAD|SLAB_ACCOUNT|
+						SLAB_PANIC),
+					     init_once);
+	pde_opener_cache =
+		kmem_cache_create("pde_opener", sizeof(struct pde_opener), 0,
+				  SLAB_ACCOUNT|SLAB_PANIC, NULL);
+	proc_dir_entry_cache = kmem_cache_create_usercopy(
+		"proc_dir_entry", SIZEOF_PDE, 0, SLAB_PANIC,
+		offsetof(struct proc_dir_entry, inline_name),
+		SIZEOF_PDE_INLINE_NAME, NULL);
+	BUILD_BUG_ON(sizeof(struct proc_dir_entry) >= SIZEOF_PDE);
+}
+
+void proc_invalidate_siblings_dcache(struct hlist_head *inodes, spinlock_t *lock)
+{
+	struct inode *inode;
+	struct proc_inode *ei;
+	struct hlist_node *node;
+	struct super_block *old_sb = NULL;
+
+	rcu_read_lock();
+	for (;;) {
+		struct super_block *sb;
+		node = hlist_first_rcu(inodes);
+		if (!node)
+			break;
+		ei = hlist_entry(node, struct proc_inode, sibling_inodes);
+		spin_lock(lock);
+		hlist_del_init_rcu(&ei->sibling_inodes);
+		spin_unlock(lock);
+
+		inode = &ei->vfs_inode;
+		sb = inode->i_sb;
+		if ((sb != old_sb) && !atomic_inc_not_zero(&sb->s_active))
+			continue;
+		inode = igrab(inode);
+		rcu_read_unlock();
+		if (sb != old_sb) {
+			if (old_sb)
+				deactivate_super(old_sb);
+			old_sb = sb;
+		}
+		if (unlikely(!inode)) {
+			rcu_read_lock();
+			continue;
+		}
+
+		if (S_ISDIR(inode->i_mode)) {
+			struct dentry *dir = d_find_any_alias(inode);
+			if (dir) {
+				d_invalidate(dir);
+				dput(dir);
+			}
+		} else {
+			struct dentry *dentry;
+			while ((dentry = d_find_alias(inode))) {
+				d_invalidate(dentry);
+				dput(dentry);
+			}
+		}
+		iput(inode);
+
+		rcu_read_lock();
+	}
+	rcu_read_unlock();
+	if (old_sb)
+		deactivate_super(old_sb);
+}
+
+static inline const char *hidepid2str(enum proc_hidepid v)
+{
+	switch (v) {
+		case HIDEPID_OFF: return "off";
+		case HIDEPID_NO_ACCESS: return "noaccess";
+		case HIDEPID_INVISIBLE: return "invisible";
+		case HIDEPID_NOT_PTRACEABLE: return "ptraceable";
+	}
+	WARN_ONCE(1, "bad hide_pid value: %d\n", v);
+	return "unknown";
+}
+
+static int proc_show_options(struct seq_file *seq, struct dentry *root)
+{
+	struct proc_fs_info *fs_info = proc_sb_info(root->d_sb);
+
+	if (!gid_eq(fs_info->pid_gid, GLOBAL_ROOT_GID))
+		seq_printf(seq, ",gid=%u", from_kgid_munged(&init_user_ns, fs_info->pid_gid));
+	if (fs_info->hide_pid != HIDEPID_OFF)
+		seq_printf(seq, ",hidepid=%s", hidepid2str(fs_info->hide_pid));
+	if (fs_info->pidonly != PROC_PIDONLY_OFF)
+		seq_printf(seq, ",subset=pid");
+
+	return 0;
+}
+
+const struct super_operations proc_sops = {
+	.alloc_inode	= proc_alloc_inode,
+	.free_inode	= proc_free_inode,
+	.drop_inode	= generic_delete_inode,
+	.evict_inode	= proc_evict_inode,
+	.statfs		= simple_statfs,
+	.show_options	= proc_show_options,
+};
+
+enum {BIAS = -1U<<31};
+
+static inline int use_pde(struct proc_dir_entry *pde)
+{
+	return likely(atomic_inc_unless_negative(&pde->in_use));
+}
+
+static void unuse_pde(struct proc_dir_entry *pde)
+{
+	if (unlikely(atomic_dec_return(&pde->in_use) == BIAS))
+		complete(pde->pde_unload_completion);
+}
+
+/*
+ * At most 2 contexts can enter this function: the one doing the last
+ * close on the descriptor and whoever is deleting PDE itself.
+ *
+ * First to enter calls ->proc_release hook and signals its completion
+ * to the second one which waits and then does nothing.
+ *
+ * PDE is locked on entry, unlocked on exit.
+ */
+static void close_pdeo(struct proc_dir_entry *pde, struct pde_opener *pdeo)
+	__releases(&pde->pde_unload_lock)
+{
+	/*
+	 * close() (proc_reg_release()) can't delete an entry and proceed:
+	 * ->release hook needs to be available at the right moment.
+	 *
+	 * rmmod (remove_proc_entry() et al) can't delete an entry and proceed:
+	 * "struct file" needs to be available at the right moment.
+	 */
+	if (pdeo->closing) {
+		/* somebody else is doing that, just wait */
+		DECLARE_COMPLETION_ONSTACK(c);
+		pdeo->c = &c;
+		spin_unlock(&pde->pde_unload_lock);
+		wait_for_completion(&c);
+	} else {
+		struct file *file;
+		struct completion *c;
+
+		pdeo->closing = true;
+		spin_unlock(&pde->pde_unload_lock);
+
+		file = pdeo->file;
+		pde->proc_ops->proc_release(file_inode(file), file);
+
+		spin_lock(&pde->pde_unload_lock);
+		/* Strictly after ->proc_release, see above. */
+		list_del(&pdeo->lh);
+		c = pdeo->c;
+		spin_unlock(&pde->pde_unload_lock);
+		if (unlikely(c))
+			complete(c);
+		kmem_cache_free(pde_opener_cache, pdeo);
+	}
+}
+
+void proc_entry_rundown(struct proc_dir_entry *de)
+{
+	DECLARE_COMPLETION_ONSTACK(c);
+	/* Wait until all existing callers into module are done. */
+	de->pde_unload_completion = &c;
+	if (atomic_add_return(BIAS, &de->in_use) != BIAS)
+		wait_for_completion(&c);
+
+	/* ->pde_openers list can't grow from now on. */
+
+	spin_lock(&de->pde_unload_lock);
+	while (!list_empty(&de->pde_openers)) {
+		struct pde_opener *pdeo;
+		pdeo = list_first_entry(&de->pde_openers, struct pde_opener, lh);
+		close_pdeo(de, pdeo);
+		spin_lock(&de->pde_unload_lock);
+	}
+	spin_unlock(&de->pde_unload_lock);
+}
+
+static loff_t proc_reg_llseek(struct file *file, loff_t offset, int whence)
+{
+	struct proc_dir_entry *pde = PDE(file_inode(file));
+	loff_t rv = -EINVAL;
+
+	if (pde_is_permanent(pde)) {
+		return pde->proc_ops->proc_lseek(file, offset, whence);
+	} else if (use_pde(pde)) {
+		rv = pde->proc_ops->proc_lseek(file, offset, whence);
+		unuse_pde(pde);
+	}
+	return rv;
+}
+
+static ssize_t proc_reg_read_iter(struct kiocb *iocb, struct iov_iter *iter)
+{
+	struct proc_dir_entry *pde = PDE(file_inode(iocb->ki_filp));
+	ssize_t ret;
+
+	if (pde_is_permanent(pde))
+		return pde->proc_ops->proc_read_iter(iocb, iter);
+
+	if (!use_pde(pde))
+		return -EIO;
+	ret = pde->proc_ops->proc_read_iter(iocb, iter);
+	unuse_pde(pde);
+	return ret;
+}
+
+static ssize_t pde_read(struct proc_dir_entry *pde, struct file *file, char __user *buf, size_t count, loff_t *ppos)
+{
+	typeof_member(struct proc_ops, proc_read) read;
+
+	read = pde->proc_ops->proc_read;
+	if (read)
+		return read(file, buf, count, ppos);
+	return -EIO;
+}
+
+static ssize_t proc_reg_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
+{
+	struct proc_dir_entry *pde = PDE(file_inode(file));
+	ssize_t rv = -EIO;
+
+	if (pde_is_permanent(pde)) {
+		return pde_read(pde, file, buf, count, ppos);
+	} else if (use_pde(pde)) {
+		rv = pde_read(pde, file, buf, count, ppos);
+		unuse_pde(pde);
+	}
+	return rv;
+}
+
+static ssize_t pde_write(struct proc_dir_entry *pde, struct file *file, const char __user *buf, size_t count, loff_t *ppos)
+{
+	typeof_member(struct proc_ops, proc_write) write;
+
+	write = pde->proc_ops->proc_write;
+	if (write)
+		return write(file, buf, count, ppos);
+	return -EIO;
+}
+
+static ssize_t proc_reg_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos)
+{
+	struct proc_dir_entry *pde = PDE(file_inode(file));
+	ssize_t rv = -EIO;
+
+	if (pde_is_permanent(pde)) {
+		return pde_write(pde, file, buf, count, ppos);
+	} else if (use_pde(pde)) {
+		rv = pde_write(pde, file, buf, count, ppos);
+		unuse_pde(pde);
+	}
+	return rv;
+}
+
+static __poll_t pde_poll(struct proc_dir_entry *pde, struct file *file, struct poll_table_struct *pts)
+{
+	typeof_member(struct proc_ops, proc_poll) poll;
+
+	poll = pde->proc_ops->proc_poll;
+	if (poll)
+		return poll(file, pts);
+	return DEFAULT_POLLMASK;
+}
+
+static __poll_t proc_reg_poll(struct file *file, struct poll_table_struct *pts)
+{
+	struct proc_dir_entry *pde = PDE(file_inode(file));
+	__poll_t rv = DEFAULT_POLLMASK;
+
+	if (pde_is_permanent(pde)) {
+		return pde_poll(pde, file, pts);
+	} else if (use_pde(pde)) {
+		rv = pde_poll(pde, file, pts);
+		unuse_pde(pde);
+	}
+	return rv;
+}
+
+static long pde_ioctl(struct proc_dir_entry *pde, struct file *file, unsigned int cmd, unsigned long arg)
+{
+	typeof_member(struct proc_ops, proc_ioctl) ioctl;
+
+	ioctl = pde->proc_ops->proc_ioctl;
+	if (ioctl)
+		return ioctl(file, cmd, arg);
+	return -ENOTTY;
+}
+
+static long proc_reg_unlocked_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
+{
+	struct proc_dir_entry *pde = PDE(file_inode(file));
+	long rv = -ENOTTY;
+
+	if (pde_is_permanent(pde)) {
+		return pde_ioctl(pde, file, cmd, arg);
+	} else if (use_pde(pde)) {
+		rv = pde_ioctl(pde, file, cmd, arg);
+		unuse_pde(pde);
+	}
+	return rv;
+}
+
+#ifdef CONFIG_COMPAT
+static long pde_compat_ioctl(struct proc_dir_entry *pde, struct file *file, unsigned int cmd, unsigned long arg)
+{
+	typeof_member(struct proc_ops, proc_compat_ioctl) compat_ioctl;
+
+	compat_ioctl = pde->proc_ops->proc_compat_ioctl;
+	if (compat_ioctl)
+		return compat_ioctl(file, cmd, arg);
+	return -ENOTTY;
+}
+
+static long proc_reg_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
+{
+	struct proc_dir_entry *pde = PDE(file_inode(file));
+	long rv = -ENOTTY;
+	if (pde_is_permanent(pde)) {
+		return pde_compat_ioctl(pde, file, cmd, arg);
+	} else if (use_pde(pde)) {
+		rv = pde_compat_ioctl(pde, file, cmd, arg);
+		unuse_pde(pde);
+	}
+	return rv;
+}
+#endif
+
+static int pde_mmap(struct proc_dir_entry *pde, struct file *file, struct vm_area_struct *vma)
+{
+	typeof_member(struct proc_ops, proc_mmap) mmap;
+
+	mmap = pde->proc_ops->proc_mmap;
+	if (mmap)
+		return mmap(file, vma);
+	return -EIO;
+}
+
+static int proc_reg_mmap(struct file *file, struct vm_area_struct *vma)
+{
+	struct proc_dir_entry *pde = PDE(file_inode(file));
+	int rv = -EIO;
+
+	if (pde_is_permanent(pde)) {
+		return pde_mmap(pde, file, vma);
+	} else if (use_pde(pde)) {
+		rv = pde_mmap(pde, file, vma);
+		unuse_pde(pde);
+	}
+	return rv;
+}
+
+static unsigned long
+pde_get_unmapped_area(struct proc_dir_entry *pde, struct file *file, unsigned long orig_addr,
+			   unsigned long len, unsigned long pgoff,
+			   unsigned long flags)
+{
+	typeof_member(struct proc_ops, proc_get_unmapped_area) get_area;
+
+	get_area = pde->proc_ops->proc_get_unmapped_area;
+#ifdef CONFIG_MMU
+	if (!get_area)
+		get_area = current->mm->get_unmapped_area;
+#endif
+	if (get_area)
+		return get_area(file, orig_addr, len, pgoff, flags);
+	return orig_addr;
+}
+
+static unsigned long
+proc_reg_get_unmapped_area(struct file *file, unsigned long orig_addr,
+			   unsigned long len, unsigned long pgoff,
+			   unsigned long flags)
+{
+	struct proc_dir_entry *pde = PDE(file_inode(file));
+	unsigned long rv = -EIO;
+
+	if (pde_is_permanent(pde)) {
+		return pde_get_unmapped_area(pde, file, orig_addr, len, pgoff, flags);
+	} else if (use_pde(pde)) {
+		rv = pde_get_unmapped_area(pde, file, orig_addr, len, pgoff, flags);
+		unuse_pde(pde);
+	}
+	return rv;
+}
+
+static int proc_reg_open(struct inode *inode, struct file *file)
+{
+	struct proc_dir_entry *pde = PDE(inode);
+	int rv = 0;
+	typeof_member(struct proc_ops, proc_open) open;
+	typeof_member(struct proc_ops, proc_release) release;
+	struct pde_opener *pdeo;
+
+	if (!pde->proc_ops->proc_lseek)
+		file->f_mode &= ~FMODE_LSEEK;
+
+	if (pde_is_permanent(pde)) {
+		open = pde->proc_ops->proc_open;
+		if (open)
+			rv = open(inode, file);
+		return rv;
+	}
+
+	/*
+	 * Ensure that
+	 * 1) PDE's ->release hook will be called no matter what
+	 *    either normally by close()/->release, or forcefully by
+	 *    rmmod/remove_proc_entry.
+	 *
+	 * 2) rmmod isn't blocked by opening file in /proc and sitting on
+	 *    the descriptor (including "rmmod foo </proc/foo" scenario).
+	 *
+	 * Save every "struct file" with custom ->release hook.
+	 */
+	if (!use_pde(pde))
+		return -ENOENT;
+
+	release = pde->proc_ops->proc_release;
+	if (release) {
+		pdeo = kmem_cache_alloc(pde_opener_cache, GFP_KERNEL);
+		if (!pdeo) {
+			rv = -ENOMEM;
+			goto out_unuse;
+		}
+	}
+
+	open = pde->proc_ops->proc_open;
+	if (open)
+		rv = open(inode, file);
+
+	if (release) {
+		if (rv == 0) {
+			/* To know what to release. */
+			pdeo->file = file;
+			pdeo->closing = false;
+			pdeo->c = NULL;
+			spin_lock(&pde->pde_unload_lock);
+			list_add(&pdeo->lh, &pde->pde_openers);
+			spin_unlock(&pde->pde_unload_lock);
+		} else
+			kmem_cache_free(pde_opener_cache, pdeo);
+	}
+
+out_unuse:
+	unuse_pde(pde);
+	return rv;
+}
+
+static int proc_reg_release(struct inode *inode, struct file *file)
+{
+	struct proc_dir_entry *pde = PDE(inode);
+	struct pde_opener *pdeo;
+
+	if (pde_is_permanent(pde)) {
+		typeof_member(struct proc_ops, proc_release) release;
+
+		release = pde->proc_ops->proc_release;
+		if (release) {
+			return release(inode, file);
+		}
+		return 0;
+	}
+
+	spin_lock(&pde->pde_unload_lock);
+	list_for_each_entry(pdeo, &pde->pde_openers, lh) {
+		if (pdeo->file == file) {
+			close_pdeo(pde, pdeo);
+			return 0;
+		}
+	}
+	spin_unlock(&pde->pde_unload_lock);
+	return 0;
+}
+
+static const struct file_operations proc_reg_file_ops = {
+	.llseek		= proc_reg_llseek,
+	.read		= proc_reg_read,
+	.write		= proc_reg_write,
+	.poll		= proc_reg_poll,
+	.unlocked_ioctl	= proc_reg_unlocked_ioctl,
+	.mmap		= proc_reg_mmap,
+	.get_unmapped_area = proc_reg_get_unmapped_area,
+	.open		= proc_reg_open,
+	.release	= proc_reg_release,
+};
+
+static const struct file_operations proc_iter_file_ops = {
+	.llseek		= proc_reg_llseek,
+	.read_iter	= proc_reg_read_iter,
+	.write		= proc_reg_write,
+	.splice_read	= generic_file_splice_read,
+	.poll		= proc_reg_poll,
+	.unlocked_ioctl	= proc_reg_unlocked_ioctl,
+	.mmap		= proc_reg_mmap,
+	.get_unmapped_area = proc_reg_get_unmapped_area,
+	.open		= proc_reg_open,
+	.release	= proc_reg_release,
+};
+
+#ifdef CONFIG_COMPAT
+static const struct file_operations proc_reg_file_ops_compat = {
+	.llseek		= proc_reg_llseek,
+	.read		= proc_reg_read,
+	.write		= proc_reg_write,
+	.poll		= proc_reg_poll,
+	.unlocked_ioctl	= proc_reg_unlocked_ioctl,
+	.compat_ioctl	= proc_reg_compat_ioctl,
+	.mmap		= proc_reg_mmap,
+	.get_unmapped_area = proc_reg_get_unmapped_area,
+	.open		= proc_reg_open,
+	.release	= proc_reg_release,
+};
+
+static const struct file_operations proc_iter_file_ops_compat = {
+	.llseek		= proc_reg_llseek,
+	.read_iter	= proc_reg_read_iter,
+	.splice_read	= generic_file_splice_read,
+	.write		= proc_reg_write,
+	.poll		= proc_reg_poll,
+	.unlocked_ioctl	= proc_reg_unlocked_ioctl,
+	.compat_ioctl	= proc_reg_compat_ioctl,
+	.mmap		= proc_reg_mmap,
+	.get_unmapped_area = proc_reg_get_unmapped_area,
+	.open		= proc_reg_open,
+	.release	= proc_reg_release,
+};
+#endif
+
+static void proc_put_link(void *p)
+{
+	unuse_pde(p);
+}
+
+static const char *proc_get_link(struct dentry *dentry,
+				 struct inode *inode,
+				 struct delayed_call *done)
+{
+	struct proc_dir_entry *pde = PDE(inode);
+	if (!use_pde(pde))
+		return ERR_PTR(-EINVAL);
+	set_delayed_call(done, proc_put_link, pde);
+	return pde->data;
+}
+
+const struct inode_operations proc_link_inode_operations = {
+	.get_link	= proc_get_link,
+};
+
+struct inode *proc_get_inode(struct super_block *sb, struct proc_dir_entry *de)
+{
+	struct inode *inode = new_inode(sb);
+
+	if (!inode) {
+		pde_put(de);
+		return NULL;
+	}
+
+	inode->i_private = de->data;
+	inode->i_ino = de->low_ino;
+	inode->i_mtime = inode->i_atime = inode->i_ctime = current_time(inode);
+	PROC_I(inode)->pde = de;
+	if (is_empty_pde(de)) {
+		make_empty_dir_inode(inode);
+		return inode;
+	}
+
+	if (de->mode) {
+		inode->i_mode = de->mode;
+		inode->i_uid = de->uid;
+		inode->i_gid = de->gid;
+	}
+	if (de->size)
+		inode->i_size = de->size;
+	if (de->nlink)
+		set_nlink(inode, de->nlink);
+
+	if (S_ISREG(inode->i_mode)) {
+		inode->i_op = de->proc_iops;
+		if (de->proc_ops->proc_read_iter)
+			inode->i_fop = &proc_iter_file_ops;
+		else
+			inode->i_fop = &proc_reg_file_ops;
+#ifdef CONFIG_COMPAT
+		if (de->proc_ops->proc_compat_ioctl) {
+			if (de->proc_ops->proc_read_iter)
+				inode->i_fop = &proc_iter_file_ops_compat;
+			else
+				inode->i_fop = &proc_reg_file_ops_compat;
+		}
+#endif
+	} else if (S_ISDIR(inode->i_mode)) {
+		inode->i_op = de->proc_iops;
+		inode->i_fop = de->proc_dir_ops;
+	} else if (S_ISLNK(inode->i_mode)) {
+		inode->i_op = de->proc_iops;
+		inode->i_fop = NULL;
+	} else {
+		BUG();
+	}
+	return inode;
+}
diff --git a/fs/proc/internal.h b/fs/proc/internal.h
new file mode 100644
index 000000000..6b921826d
--- /dev/null
+++ b/fs/proc/internal.h
@@ -0,0 +1,318 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/* Internal procfs definitions
+ *
+ * Copyright (C) 2004 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ */
+
+#include <linux/proc_fs.h>
+#include <linux/proc_ns.h>
+#include <linux/refcount.h>
+#include <linux/spinlock.h>
+#include <linux/atomic.h>
+#include <linux/binfmts.h>
+#include <linux/sched/coredump.h>
+#include <linux/sched/task.h>
+
+struct ctl_table_header;
+struct mempolicy;
+
+/*
+ * This is not completely implemented yet. The idea is to
+ * create an in-memory tree (like the actual /proc filesystem
+ * tree) of these proc_dir_entries, so that we can dynamically
+ * add new files to /proc.
+ *
+ * parent/subdir are used for the directory structure (every /proc file has a
+ * parent, but "subdir" is empty for all non-directory entries).
+ * subdir_node is used to build the rb tree "subdir" of the parent.
+ */
+struct proc_dir_entry {
+	/*
+	 * number of callers into module in progress;
+	 * negative -> it's going away RSN
+	 */
+	atomic_t in_use;
+	refcount_t refcnt;
+	struct list_head pde_openers;	/* who did ->open, but not ->release */
+	/* protects ->pde_openers and all struct pde_opener instances */
+	spinlock_t pde_unload_lock;
+	struct completion *pde_unload_completion;
+	const struct inode_operations *proc_iops;
+	union {
+		const struct proc_ops *proc_ops;
+		const struct file_operations *proc_dir_ops;
+	};
+	const struct dentry_operations *proc_dops;
+	union {
+		const struct seq_operations *seq_ops;
+		int (*single_show)(struct seq_file *, void *);
+	};
+	proc_write_t write;
+	void *data;
+	unsigned int state_size;
+	unsigned int low_ino;
+	nlink_t nlink;
+	kuid_t uid;
+	kgid_t gid;
+	loff_t size;
+	struct proc_dir_entry *parent;
+	struct rb_root subdir;
+	struct rb_node subdir_node;
+	char *name;
+	umode_t mode;
+	u8 flags;
+	u8 namelen;
+	char inline_name[];
+} __randomize_layout;
+
+#define SIZEOF_PDE	(				\
+	sizeof(struct proc_dir_entry) < 128 ? 128 :	\
+	sizeof(struct proc_dir_entry) < 192 ? 192 :	\
+	sizeof(struct proc_dir_entry) < 256 ? 256 :	\
+	sizeof(struct proc_dir_entry) < 512 ? 512 :	\
+	0)
+#define SIZEOF_PDE_INLINE_NAME (SIZEOF_PDE - sizeof(struct proc_dir_entry))
+
+static inline bool pde_is_permanent(const struct proc_dir_entry *pde)
+{
+	return pde->flags & PROC_ENTRY_PERMANENT;
+}
+
+static inline void pde_make_permanent(struct proc_dir_entry *pde)
+{
+	pde->flags |= PROC_ENTRY_PERMANENT;
+}
+
+extern struct kmem_cache *proc_dir_entry_cache;
+void pde_free(struct proc_dir_entry *pde);
+
+union proc_op {
+	int (*proc_get_link)(struct dentry *, struct path *);
+	int (*proc_show)(struct seq_file *m,
+		struct pid_namespace *ns, struct pid *pid,
+		struct task_struct *task);
+	const char *lsm;
+};
+
+struct proc_inode {
+	struct pid *pid;
+	unsigned int fd;
+	union proc_op op;
+	struct proc_dir_entry *pde;
+	struct ctl_table_header *sysctl;
+	struct ctl_table *sysctl_entry;
+	struct hlist_node sibling_inodes;
+	const struct proc_ns_operations *ns_ops;
+	struct inode vfs_inode;
+} __randomize_layout;
+
+/*
+ * General functions
+ */
+static inline struct proc_inode *PROC_I(const struct inode *inode)
+{
+	return container_of(inode, struct proc_inode, vfs_inode);
+}
+
+static inline struct proc_dir_entry *PDE(const struct inode *inode)
+{
+	return PROC_I(inode)->pde;
+}
+
+static inline struct pid *proc_pid(const struct inode *inode)
+{
+	return PROC_I(inode)->pid;
+}
+
+static inline struct task_struct *get_proc_task(const struct inode *inode)
+{
+	return get_pid_task(proc_pid(inode), PIDTYPE_PID);
+}
+
+void task_dump_owner(struct task_struct *task, umode_t mode,
+		     kuid_t *ruid, kgid_t *rgid);
+
+unsigned name_to_int(const struct qstr *qstr);
+/*
+ * Offset of the first process in the /proc root directory..
+ */
+#define FIRST_PROCESS_ENTRY 256
+
+/* Worst case buffer size needed for holding an integer. */
+#define PROC_NUMBUF 13
+
+/*
+ * array.c
+ */
+extern const struct file_operations proc_tid_children_operations;
+
+extern void proc_task_name(struct seq_file *m, struct task_struct *p,
+			   bool escape);
+extern int proc_tid_stat(struct seq_file *, struct pid_namespace *,
+			 struct pid *, struct task_struct *);
+extern int proc_tgid_stat(struct seq_file *, struct pid_namespace *,
+			  struct pid *, struct task_struct *);
+extern int proc_pid_status(struct seq_file *, struct pid_namespace *,
+			   struct pid *, struct task_struct *);
+extern int proc_pid_statm(struct seq_file *, struct pid_namespace *,
+			  struct pid *, struct task_struct *);
+
+/*
+ * base.c
+ */
+extern const struct dentry_operations pid_dentry_operations;
+extern int pid_getattr(struct user_namespace *, const struct path *,
+		       struct kstat *, u32, unsigned int);
+extern int proc_setattr(struct user_namespace *, struct dentry *,
+			struct iattr *);
+extern void proc_pid_evict_inode(struct proc_inode *);
+extern struct inode *proc_pid_make_inode(struct super_block *, struct task_struct *, umode_t);
+extern void pid_update_inode(struct task_struct *, struct inode *);
+extern int pid_delete_dentry(const struct dentry *);
+extern int proc_pid_readdir(struct file *, struct dir_context *);
+struct dentry *proc_pid_lookup(struct dentry *, unsigned int);
+extern loff_t mem_lseek(struct file *, loff_t, int);
+
+/* Lookups */
+typedef struct dentry *instantiate_t(struct dentry *,
+				     struct task_struct *, const void *);
+bool proc_fill_cache(struct file *, struct dir_context *, const char *, unsigned int,
+			   instantiate_t, struct task_struct *, const void *);
+
+/*
+ * generic.c
+ */
+struct proc_dir_entry *proc_create_reg(const char *name, umode_t mode,
+		struct proc_dir_entry **parent, void *data);
+struct proc_dir_entry *proc_register(struct proc_dir_entry *dir,
+		struct proc_dir_entry *dp);
+extern struct dentry *proc_lookup(struct inode *, struct dentry *, unsigned int);
+struct dentry *proc_lookup_de(struct inode *, struct dentry *, struct proc_dir_entry *);
+extern int proc_readdir(struct file *, struct dir_context *);
+int proc_readdir_de(struct file *, struct dir_context *, struct proc_dir_entry *);
+
+static inline void pde_get(struct proc_dir_entry *pde)
+{
+	refcount_inc(&pde->refcnt);
+}
+extern void pde_put(struct proc_dir_entry *);
+
+static inline bool is_empty_pde(const struct proc_dir_entry *pde)
+{
+	return S_ISDIR(pde->mode) && !pde->proc_iops;
+}
+extern ssize_t proc_simple_write(struct file *, const char __user *, size_t, loff_t *);
+
+/*
+ * inode.c
+ */
+struct pde_opener {
+	struct list_head lh;
+	struct file *file;
+	bool closing;
+	struct completion *c;
+} __randomize_layout;
+extern const struct inode_operations proc_link_inode_operations;
+extern const struct inode_operations proc_pid_link_inode_operations;
+extern const struct super_operations proc_sops;
+
+void proc_init_kmemcache(void);
+void proc_invalidate_siblings_dcache(struct hlist_head *inodes, spinlock_t *lock);
+void set_proc_pid_nlink(void);
+extern struct inode *proc_get_inode(struct super_block *, struct proc_dir_entry *);
+extern void proc_entry_rundown(struct proc_dir_entry *);
+
+/*
+ * proc_namespaces.c
+ */
+extern const struct inode_operations proc_ns_dir_inode_operations;
+extern const struct file_operations proc_ns_dir_operations;
+
+/*
+ * proc_net.c
+ */
+extern const struct file_operations proc_net_operations;
+extern const struct inode_operations proc_net_inode_operations;
+
+#ifdef CONFIG_NET
+extern int proc_net_init(void);
+#else
+static inline int proc_net_init(void) { return 0; }
+#endif
+
+/*
+ * proc_self.c
+ */
+extern int proc_setup_self(struct super_block *);
+
+/*
+ * proc_thread_self.c
+ */
+extern int proc_setup_thread_self(struct super_block *);
+extern void proc_thread_self_init(void);
+
+/*
+ * proc_sysctl.c
+ */
+#ifdef CONFIG_PROC_SYSCTL
+extern int proc_sys_init(void);
+extern void proc_sys_evict_inode(struct inode *inode,
+				 struct ctl_table_header *head);
+#else
+static inline void proc_sys_init(void) { }
+static inline void proc_sys_evict_inode(struct  inode *inode,
+					struct ctl_table_header *head) { }
+#endif
+
+/*
+ * proc_tty.c
+ */
+#ifdef CONFIG_TTY
+extern void proc_tty_init(void);
+#else
+static inline void proc_tty_init(void) {}
+#endif
+
+/*
+ * root.c
+ */
+extern struct proc_dir_entry proc_root;
+
+extern void proc_self_init(void);
+
+/*
+ * task_[no]mmu.c
+ */
+struct mem_size_stats;
+struct proc_maps_private {
+	struct inode *inode;
+	struct task_struct *task;
+	struct mm_struct *mm;
+	struct vma_iterator iter;
+#ifdef CONFIG_NUMA
+	struct mempolicy *task_mempolicy;
+#endif
+} __randomize_layout;
+
+struct mm_struct *proc_mem_open(struct inode *inode, unsigned int mode);
+
+extern const struct file_operations proc_pid_maps_operations;
+extern const struct file_operations proc_pid_numa_maps_operations;
+extern const struct file_operations proc_pid_smaps_operations;
+extern const struct file_operations proc_pid_smaps_rollup_operations;
+extern const struct file_operations proc_clear_refs_operations;
+extern const struct file_operations proc_pagemap_operations;
+
+extern unsigned long task_vsize(struct mm_struct *);
+extern unsigned long task_statm(struct mm_struct *,
+				unsigned long *, unsigned long *,
+				unsigned long *, unsigned long *);
+extern void task_mem(struct seq_file *, struct mm_struct *);
+
+extern const struct dentry_operations proc_net_dentry_ops;
+static inline void pde_force_lookup(struct proc_dir_entry *pde)
+{
+	/* /proc/net/ entries can be changed under us by setns(CLONE_NEWNET) */
+	pde->proc_dops = &proc_net_dentry_ops;
+}
diff --git a/fs/proc/interrupts.c b/fs/proc/interrupts.c
new file mode 100644
index 000000000..cb0edc7cb
--- /dev/null
+++ b/fs/proc/interrupts.c
@@ -0,0 +1,42 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/fs.h>
+#include <linux/init.h>
+#include <linux/interrupt.h>
+#include <linux/irqnr.h>
+#include <linux/proc_fs.h>
+#include <linux/seq_file.h>
+
+/*
+ * /proc/interrupts
+ */
+static void *int_seq_start(struct seq_file *f, loff_t *pos)
+{
+	return (*pos <= nr_irqs) ? pos : NULL;
+}
+
+static void *int_seq_next(struct seq_file *f, void *v, loff_t *pos)
+{
+	(*pos)++;
+	if (*pos > nr_irqs)
+		return NULL;
+	return pos;
+}
+
+static void int_seq_stop(struct seq_file *f, void *v)
+{
+	/* Nothing to do */
+}
+
+static const struct seq_operations int_seq_ops = {
+	.start = int_seq_start,
+	.next  = int_seq_next,
+	.stop  = int_seq_stop,
+	.show  = show_interrupts
+};
+
+static int __init proc_interrupts_init(void)
+{
+	proc_create_seq("interrupts", 0, NULL, &int_seq_ops);
+	return 0;
+}
+fs_initcall(proc_interrupts_init);
diff --git a/fs/proc/kcore.c b/fs/proc/kcore.c
new file mode 100644
index 000000000..dff921f7c
--- /dev/null
+++ b/fs/proc/kcore.c
@@ -0,0 +1,701 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ *	fs/proc/kcore.c kernel ELF core dumper
+ *
+ *	Modelled on fs/exec.c:aout_core_dump()
+ *	Jeremy Fitzhardinge <jeremy@sw.oz.au>
+ *	ELF version written by David Howells <David.Howells@nexor.co.uk>
+ *	Modified and incorporated into 2.3.x by Tigran Aivazian <tigran@veritas.com>
+ *	Support to dump vmalloc'd areas (ELF only), Tigran Aivazian <tigran@veritas.com>
+ *	Safe accesses to vmalloc/direct-mapped discontiguous areas, Kanoj Sarcar <kanoj@sgi.com>
+ */
+
+#include <linux/crash_core.h>
+#include <linux/mm.h>
+#include <linux/proc_fs.h>
+#include <linux/kcore.h>
+#include <linux/user.h>
+#include <linux/capability.h>
+#include <linux/elf.h>
+#include <linux/elfcore.h>
+#include <linux/notifier.h>
+#include <linux/vmalloc.h>
+#include <linux/highmem.h>
+#include <linux/printk.h>
+#include <linux/memblock.h>
+#include <linux/init.h>
+#include <linux/slab.h>
+#include <linux/uaccess.h>
+#include <asm/io.h>
+#include <linux/list.h>
+#include <linux/ioport.h>
+#include <linux/memory.h>
+#include <linux/sched/task.h>
+#include <linux/security.h>
+#include <asm/sections.h>
+#include "internal.h"
+
+#define CORE_STR "CORE"
+
+#ifndef ELF_CORE_EFLAGS
+#define ELF_CORE_EFLAGS	0
+#endif
+
+static struct proc_dir_entry *proc_root_kcore;
+
+
+#ifndef kc_vaddr_to_offset
+#define	kc_vaddr_to_offset(v) ((v) - PAGE_OFFSET)
+#endif
+#ifndef	kc_offset_to_vaddr
+#define	kc_offset_to_vaddr(o) ((o) + PAGE_OFFSET)
+#endif
+
+static LIST_HEAD(kclist_head);
+static DECLARE_RWSEM(kclist_lock);
+static int kcore_need_update = 1;
+
+/*
+ * Returns > 0 for RAM pages, 0 for non-RAM pages, < 0 on error
+ * Same as oldmem_pfn_is_ram in vmcore
+ */
+static int (*mem_pfn_is_ram)(unsigned long pfn);
+
+int __init register_mem_pfn_is_ram(int (*fn)(unsigned long pfn))
+{
+	if (mem_pfn_is_ram)
+		return -EBUSY;
+	mem_pfn_is_ram = fn;
+	return 0;
+}
+
+static int pfn_is_ram(unsigned long pfn)
+{
+	if (mem_pfn_is_ram)
+		return mem_pfn_is_ram(pfn);
+	else
+		return 1;
+}
+
+/* This doesn't grab kclist_lock, so it should only be used at init time. */
+void __init kclist_add(struct kcore_list *new, void *addr, size_t size,
+		       int type)
+{
+	new->addr = (unsigned long)addr;
+	new->size = size;
+	new->type = type;
+
+	list_add_tail(&new->list, &kclist_head);
+}
+
+static size_t get_kcore_size(int *nphdr, size_t *phdrs_len, size_t *notes_len,
+			     size_t *data_offset)
+{
+	size_t try, size;
+	struct kcore_list *m;
+
+	*nphdr = 1; /* PT_NOTE */
+	size = 0;
+
+	list_for_each_entry(m, &kclist_head, list) {
+		try = kc_vaddr_to_offset((size_t)m->addr + m->size);
+		if (try > size)
+			size = try;
+		*nphdr = *nphdr + 1;
+	}
+
+	*phdrs_len = *nphdr * sizeof(struct elf_phdr);
+	*notes_len = (4 * sizeof(struct elf_note) +
+		      3 * ALIGN(sizeof(CORE_STR), 4) +
+		      VMCOREINFO_NOTE_NAME_BYTES +
+		      ALIGN(sizeof(struct elf_prstatus), 4) +
+		      ALIGN(sizeof(struct elf_prpsinfo), 4) +
+		      ALIGN(arch_task_struct_size, 4) +
+		      ALIGN(vmcoreinfo_size, 4));
+	*data_offset = PAGE_ALIGN(sizeof(struct elfhdr) + *phdrs_len +
+				  *notes_len);
+	return *data_offset + size;
+}
+
+#ifdef CONFIG_HIGHMEM
+/*
+ * If no highmem, we can assume [0...max_low_pfn) continuous range of memory
+ * because memory hole is not as big as !HIGHMEM case.
+ * (HIGHMEM is special because part of memory is _invisible_ from the kernel.)
+ */
+static int kcore_ram_list(struct list_head *head)
+{
+	struct kcore_list *ent;
+
+	ent = kmalloc(sizeof(*ent), GFP_KERNEL);
+	if (!ent)
+		return -ENOMEM;
+	ent->addr = (unsigned long)__va(0);
+	ent->size = max_low_pfn << PAGE_SHIFT;
+	ent->type = KCORE_RAM;
+	list_add(&ent->list, head);
+	return 0;
+}
+
+#else /* !CONFIG_HIGHMEM */
+
+#ifdef CONFIG_SPARSEMEM_VMEMMAP
+/* calculate vmemmap's address from given system ram pfn and register it */
+static int
+get_sparsemem_vmemmap_info(struct kcore_list *ent, struct list_head *head)
+{
+	unsigned long pfn = __pa(ent->addr) >> PAGE_SHIFT;
+	unsigned long nr_pages = ent->size >> PAGE_SHIFT;
+	unsigned long start, end;
+	struct kcore_list *vmm, *tmp;
+
+
+	start = ((unsigned long)pfn_to_page(pfn)) & PAGE_MASK;
+	end = ((unsigned long)pfn_to_page(pfn + nr_pages)) - 1;
+	end = PAGE_ALIGN(end);
+	/* overlap check (because we have to align page */
+	list_for_each_entry(tmp, head, list) {
+		if (tmp->type != KCORE_VMEMMAP)
+			continue;
+		if (start < tmp->addr + tmp->size)
+			if (end > tmp->addr)
+				end = tmp->addr;
+	}
+	if (start < end) {
+		vmm = kmalloc(sizeof(*vmm), GFP_KERNEL);
+		if (!vmm)
+			return 0;
+		vmm->addr = start;
+		vmm->size = end - start;
+		vmm->type = KCORE_VMEMMAP;
+		list_add_tail(&vmm->list, head);
+	}
+	return 1;
+
+}
+#else
+static int
+get_sparsemem_vmemmap_info(struct kcore_list *ent, struct list_head *head)
+{
+	return 1;
+}
+
+#endif
+
+static int
+kclist_add_private(unsigned long pfn, unsigned long nr_pages, void *arg)
+{
+	struct list_head *head = (struct list_head *)arg;
+	struct kcore_list *ent;
+	struct page *p;
+
+	if (!pfn_valid(pfn))
+		return 1;
+
+	p = pfn_to_page(pfn);
+
+	ent = kmalloc(sizeof(*ent), GFP_KERNEL);
+	if (!ent)
+		return -ENOMEM;
+	ent->addr = (unsigned long)page_to_virt(p);
+	ent->size = nr_pages << PAGE_SHIFT;
+
+	if (!virt_addr_valid(ent->addr))
+		goto free_out;
+
+	/* cut not-mapped area. ....from ppc-32 code. */
+	if (ULONG_MAX - ent->addr < ent->size)
+		ent->size = ULONG_MAX - ent->addr;
+
+	/*
+	 * We've already checked virt_addr_valid so we know this address
+	 * is a valid pointer, therefore we can check against it to determine
+	 * if we need to trim
+	 */
+	if (VMALLOC_START > ent->addr) {
+		if (VMALLOC_START - ent->addr < ent->size)
+			ent->size = VMALLOC_START - ent->addr;
+	}
+
+	ent->type = KCORE_RAM;
+	list_add_tail(&ent->list, head);
+
+	if (!get_sparsemem_vmemmap_info(ent, head)) {
+		list_del(&ent->list);
+		goto free_out;
+	}
+
+	return 0;
+free_out:
+	kfree(ent);
+	return 1;
+}
+
+static int kcore_ram_list(struct list_head *list)
+{
+	int nid, ret;
+	unsigned long end_pfn;
+
+	/* Not inialized....update now */
+	/* find out "max pfn" */
+	end_pfn = 0;
+	for_each_node_state(nid, N_MEMORY) {
+		unsigned long node_end;
+		node_end = node_end_pfn(nid);
+		if (end_pfn < node_end)
+			end_pfn = node_end;
+	}
+	/* scan 0 to max_pfn */
+	ret = walk_system_ram_range(0, end_pfn, list, kclist_add_private);
+	if (ret)
+		return -ENOMEM;
+	return 0;
+}
+#endif /* CONFIG_HIGHMEM */
+
+static int kcore_update_ram(void)
+{
+	LIST_HEAD(list);
+	LIST_HEAD(garbage);
+	int nphdr;
+	size_t phdrs_len, notes_len, data_offset;
+	struct kcore_list *tmp, *pos;
+	int ret = 0;
+
+	down_write(&kclist_lock);
+	if (!xchg(&kcore_need_update, 0))
+		goto out;
+
+	ret = kcore_ram_list(&list);
+	if (ret) {
+		/* Couldn't get the RAM list, try again next time. */
+		WRITE_ONCE(kcore_need_update, 1);
+		list_splice_tail(&list, &garbage);
+		goto out;
+	}
+
+	list_for_each_entry_safe(pos, tmp, &kclist_head, list) {
+		if (pos->type == KCORE_RAM || pos->type == KCORE_VMEMMAP)
+			list_move(&pos->list, &garbage);
+	}
+	list_splice_tail(&list, &kclist_head);
+
+	proc_root_kcore->size = get_kcore_size(&nphdr, &phdrs_len, &notes_len,
+					       &data_offset);
+
+out:
+	up_write(&kclist_lock);
+	list_for_each_entry_safe(pos, tmp, &garbage, list) {
+		list_del(&pos->list);
+		kfree(pos);
+	}
+	return ret;
+}
+
+static void append_kcore_note(char *notes, size_t *i, const char *name,
+			      unsigned int type, const void *desc,
+			      size_t descsz)
+{
+	struct elf_note *note = (struct elf_note *)&notes[*i];
+
+	note->n_namesz = strlen(name) + 1;
+	note->n_descsz = descsz;
+	note->n_type = type;
+	*i += sizeof(*note);
+	memcpy(&notes[*i], name, note->n_namesz);
+	*i = ALIGN(*i + note->n_namesz, 4);
+	memcpy(&notes[*i], desc, descsz);
+	*i = ALIGN(*i + descsz, 4);
+}
+
+static ssize_t
+read_kcore(struct file *file, char __user *buffer, size_t buflen, loff_t *fpos)
+{
+	char *buf = file->private_data;
+	size_t phdrs_offset, notes_offset, data_offset;
+	size_t page_offline_frozen = 1;
+	size_t phdrs_len, notes_len;
+	struct kcore_list *m;
+	size_t tsz;
+	int nphdr;
+	unsigned long start;
+	size_t orig_buflen = buflen;
+	int ret = 0;
+
+	down_read(&kclist_lock);
+	/*
+	 * Don't race against drivers that set PageOffline() and expect no
+	 * further page access.
+	 */
+	page_offline_freeze();
+
+	get_kcore_size(&nphdr, &phdrs_len, &notes_len, &data_offset);
+	phdrs_offset = sizeof(struct elfhdr);
+	notes_offset = phdrs_offset + phdrs_len;
+
+	/* ELF file header. */
+	if (buflen && *fpos < sizeof(struct elfhdr)) {
+		struct elfhdr ehdr = {
+			.e_ident = {
+				[EI_MAG0] = ELFMAG0,
+				[EI_MAG1] = ELFMAG1,
+				[EI_MAG2] = ELFMAG2,
+				[EI_MAG3] = ELFMAG3,
+				[EI_CLASS] = ELF_CLASS,
+				[EI_DATA] = ELF_DATA,
+				[EI_VERSION] = EV_CURRENT,
+				[EI_OSABI] = ELF_OSABI,
+			},
+			.e_type = ET_CORE,
+			.e_machine = ELF_ARCH,
+			.e_version = EV_CURRENT,
+			.e_phoff = sizeof(struct elfhdr),
+			.e_flags = ELF_CORE_EFLAGS,
+			.e_ehsize = sizeof(struct elfhdr),
+			.e_phentsize = sizeof(struct elf_phdr),
+			.e_phnum = nphdr,
+		};
+
+		tsz = min_t(size_t, buflen, sizeof(struct elfhdr) - *fpos);
+		if (copy_to_user(buffer, (char *)&ehdr + *fpos, tsz)) {
+			ret = -EFAULT;
+			goto out;
+		}
+
+		buffer += tsz;
+		buflen -= tsz;
+		*fpos += tsz;
+	}
+
+	/* ELF program headers. */
+	if (buflen && *fpos < phdrs_offset + phdrs_len) {
+		struct elf_phdr *phdrs, *phdr;
+
+		phdrs = kzalloc(phdrs_len, GFP_KERNEL);
+		if (!phdrs) {
+			ret = -ENOMEM;
+			goto out;
+		}
+
+		phdrs[0].p_type = PT_NOTE;
+		phdrs[0].p_offset = notes_offset;
+		phdrs[0].p_filesz = notes_len;
+
+		phdr = &phdrs[1];
+		list_for_each_entry(m, &kclist_head, list) {
+			phdr->p_type = PT_LOAD;
+			phdr->p_flags = PF_R | PF_W | PF_X;
+			phdr->p_offset = kc_vaddr_to_offset(m->addr) + data_offset;
+			phdr->p_vaddr = (size_t)m->addr;
+			if (m->type == KCORE_RAM)
+				phdr->p_paddr = __pa(m->addr);
+			else if (m->type == KCORE_TEXT)
+				phdr->p_paddr = __pa_symbol(m->addr);
+			else
+				phdr->p_paddr = (elf_addr_t)-1;
+			phdr->p_filesz = phdr->p_memsz = m->size;
+			phdr->p_align = PAGE_SIZE;
+			phdr++;
+		}
+
+		tsz = min_t(size_t, buflen, phdrs_offset + phdrs_len - *fpos);
+		if (copy_to_user(buffer, (char *)phdrs + *fpos - phdrs_offset,
+				 tsz)) {
+			kfree(phdrs);
+			ret = -EFAULT;
+			goto out;
+		}
+		kfree(phdrs);
+
+		buffer += tsz;
+		buflen -= tsz;
+		*fpos += tsz;
+	}
+
+	/* ELF note segment. */
+	if (buflen && *fpos < notes_offset + notes_len) {
+		struct elf_prstatus prstatus = {};
+		struct elf_prpsinfo prpsinfo = {
+			.pr_sname = 'R',
+			.pr_fname = "vmlinux",
+		};
+		char *notes;
+		size_t i = 0;
+
+		strlcpy(prpsinfo.pr_psargs, saved_command_line,
+			sizeof(prpsinfo.pr_psargs));
+
+		notes = kzalloc(notes_len, GFP_KERNEL);
+		if (!notes) {
+			ret = -ENOMEM;
+			goto out;
+		}
+
+		append_kcore_note(notes, &i, CORE_STR, NT_PRSTATUS, &prstatus,
+				  sizeof(prstatus));
+		append_kcore_note(notes, &i, CORE_STR, NT_PRPSINFO, &prpsinfo,
+				  sizeof(prpsinfo));
+		append_kcore_note(notes, &i, CORE_STR, NT_TASKSTRUCT, current,
+				  arch_task_struct_size);
+		/*
+		 * vmcoreinfo_size is mostly constant after init time, but it
+		 * can be changed by crash_save_vmcoreinfo(). Racing here with a
+		 * panic on another CPU before the machine goes down is insanely
+		 * unlikely, but it's better to not leave potential buffer
+		 * overflows lying around, regardless.
+		 */
+		append_kcore_note(notes, &i, VMCOREINFO_NOTE_NAME, 0,
+				  vmcoreinfo_data,
+				  min(vmcoreinfo_size, notes_len - i));
+
+		tsz = min_t(size_t, buflen, notes_offset + notes_len - *fpos);
+		if (copy_to_user(buffer, notes + *fpos - notes_offset, tsz)) {
+			kfree(notes);
+			ret = -EFAULT;
+			goto out;
+		}
+		kfree(notes);
+
+		buffer += tsz;
+		buflen -= tsz;
+		*fpos += tsz;
+	}
+
+	/*
+	 * Check to see if our file offset matches with any of
+	 * the addresses in the elf_phdr on our list.
+	 */
+	start = kc_offset_to_vaddr(*fpos - data_offset);
+	if ((tsz = (PAGE_SIZE - (start & ~PAGE_MASK))) > buflen)
+		tsz = buflen;
+
+	m = NULL;
+	while (buflen) {
+		struct page *page;
+		unsigned long pfn;
+
+		/*
+		 * If this is the first iteration or the address is not within
+		 * the previous entry, search for a matching entry.
+		 */
+		if (!m || start < m->addr || start >= m->addr + m->size) {
+			struct kcore_list *iter;
+
+			m = NULL;
+			list_for_each_entry(iter, &kclist_head, list) {
+				if (start >= iter->addr &&
+				    start < iter->addr + iter->size) {
+					m = iter;
+					break;
+				}
+			}
+		}
+
+		if (page_offline_frozen++ % MAX_ORDER_NR_PAGES == 0) {
+			page_offline_thaw();
+			cond_resched();
+			page_offline_freeze();
+		}
+
+		if (!m) {
+			if (clear_user(buffer, tsz)) {
+				ret = -EFAULT;
+				goto out;
+			}
+			goto skip;
+		}
+
+		switch (m->type) {
+		case KCORE_VMALLOC:
+			vread(buf, (char *)start, tsz);
+			/* we have to zero-fill user buffer even if no read */
+			if (copy_to_user(buffer, buf, tsz)) {
+				ret = -EFAULT;
+				goto out;
+			}
+			break;
+		case KCORE_USER:
+			/* User page is handled prior to normal kernel page: */
+			if (copy_to_user(buffer, (char *)start, tsz)) {
+				ret = -EFAULT;
+				goto out;
+			}
+			break;
+		case KCORE_RAM:
+			pfn = __pa(start) >> PAGE_SHIFT;
+			page = pfn_to_online_page(pfn);
+
+			/*
+			 * Don't read offline sections, logically offline pages
+			 * (e.g., inflated in a balloon), hwpoisoned pages,
+			 * and explicitly excluded physical ranges.
+			 */
+			if (!page || PageOffline(page) ||
+			    is_page_hwpoison(page) || !pfn_is_ram(pfn)) {
+				if (clear_user(buffer, tsz)) {
+					ret = -EFAULT;
+					goto out;
+				}
+				break;
+			}
+			fallthrough;
+		case KCORE_VMEMMAP:
+		case KCORE_TEXT:
+			if (kern_addr_valid(start)) {
+				/*
+				 * Using bounce buffer to bypass the
+				 * hardened user copy kernel text checks.
+				 */
+				if (copy_from_kernel_nofault(buf, (void *)start,
+						tsz)) {
+					if (clear_user(buffer, tsz)) {
+						ret = -EFAULT;
+						goto out;
+					}
+				} else {
+					if (copy_to_user(buffer, buf, tsz)) {
+						ret = -EFAULT;
+						goto out;
+					}
+				}
+			} else {
+				if (clear_user(buffer, tsz)) {
+					ret = -EFAULT;
+					goto out;
+				}
+			}
+			break;
+		default:
+			pr_warn_once("Unhandled KCORE type: %d\n", m->type);
+			if (clear_user(buffer, tsz)) {
+				ret = -EFAULT;
+				goto out;
+			}
+		}
+skip:
+		buflen -= tsz;
+		*fpos += tsz;
+		buffer += tsz;
+		start += tsz;
+		tsz = (buflen > PAGE_SIZE ? PAGE_SIZE : buflen);
+	}
+
+out:
+	page_offline_thaw();
+	up_read(&kclist_lock);
+	if (ret)
+		return ret;
+	return orig_buflen - buflen;
+}
+
+static int open_kcore(struct inode *inode, struct file *filp)
+{
+	int ret = security_locked_down(LOCKDOWN_KCORE);
+
+	if (!capable(CAP_SYS_RAWIO))
+		return -EPERM;
+
+	if (ret)
+		return ret;
+
+	filp->private_data = kmalloc(PAGE_SIZE, GFP_KERNEL);
+	if (!filp->private_data)
+		return -ENOMEM;
+
+	if (kcore_need_update)
+		kcore_update_ram();
+	if (i_size_read(inode) != proc_root_kcore->size) {
+		inode_lock(inode);
+		i_size_write(inode, proc_root_kcore->size);
+		inode_unlock(inode);
+	}
+	return 0;
+}
+
+static int release_kcore(struct inode *inode, struct file *file)
+{
+	kfree(file->private_data);
+	return 0;
+}
+
+static const struct proc_ops kcore_proc_ops = {
+	.proc_read	= read_kcore,
+	.proc_open	= open_kcore,
+	.proc_release	= release_kcore,
+	.proc_lseek	= default_llseek,
+};
+
+/* just remember that we have to update kcore */
+static int __meminit kcore_callback(struct notifier_block *self,
+				    unsigned long action, void *arg)
+{
+	switch (action) {
+	case MEM_ONLINE:
+	case MEM_OFFLINE:
+		kcore_need_update = 1;
+		break;
+	}
+	return NOTIFY_OK;
+}
+
+static struct notifier_block kcore_callback_nb __meminitdata = {
+	.notifier_call = kcore_callback,
+	.priority = 0,
+};
+
+static struct kcore_list kcore_vmalloc;
+
+#ifdef CONFIG_ARCH_PROC_KCORE_TEXT
+static struct kcore_list kcore_text;
+/*
+ * If defined, special segment is used for mapping kernel text instead of
+ * direct-map area. We need to create special TEXT section.
+ */
+static void __init proc_kcore_text_init(void)
+{
+	kclist_add(&kcore_text, _text, _end - _text, KCORE_TEXT);
+}
+#else
+static void __init proc_kcore_text_init(void)
+{
+}
+#endif
+
+#if defined(CONFIG_MODULES) && defined(MODULES_VADDR)
+/*
+ * MODULES_VADDR has no intersection with VMALLOC_ADDR.
+ */
+static struct kcore_list kcore_modules;
+static void __init add_modules_range(void)
+{
+	if (MODULES_VADDR != VMALLOC_START && MODULES_END != VMALLOC_END) {
+		kclist_add(&kcore_modules, (void *)MODULES_VADDR,
+			MODULES_END - MODULES_VADDR, KCORE_VMALLOC);
+	}
+}
+#else
+static void __init add_modules_range(void)
+{
+}
+#endif
+
+static int __init proc_kcore_init(void)
+{
+	proc_root_kcore = proc_create("kcore", S_IRUSR, NULL, &kcore_proc_ops);
+	if (!proc_root_kcore) {
+		pr_err("couldn't create /proc/kcore\n");
+		return 0; /* Always returns 0. */
+	}
+	/* Store text area if it's special */
+	proc_kcore_text_init();
+	/* Store vmalloc area */
+	kclist_add(&kcore_vmalloc, (void *)VMALLOC_START,
+		VMALLOC_END - VMALLOC_START, KCORE_VMALLOC);
+	add_modules_range();
+	/* Store direct-map area from physical memory map */
+	kcore_update_ram();
+	register_hotmemory_notifier(&kcore_callback_nb);
+
+	return 0;
+}
+fs_initcall(proc_kcore_init);
diff --git a/fs/proc/kmsg.c b/fs/proc/kmsg.c
new file mode 100644
index 000000000..2fc92a13f
--- /dev/null
+++ b/fs/proc/kmsg.c
@@ -0,0 +1,63 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ *  linux/fs/proc/kmsg.c
+ *
+ *  Copyright (C) 1992  by Linus Torvalds
+ *
+ */
+
+#include <linux/types.h>
+#include <linux/errno.h>
+#include <linux/time.h>
+#include <linux/kernel.h>
+#include <linux/poll.h>
+#include <linux/proc_fs.h>
+#include <linux/fs.h>
+#include <linux/syslog.h>
+
+#include <asm/io.h>
+
+static int kmsg_open(struct inode * inode, struct file * file)
+{
+	return do_syslog(SYSLOG_ACTION_OPEN, NULL, 0, SYSLOG_FROM_PROC);
+}
+
+static int kmsg_release(struct inode * inode, struct file * file)
+{
+	(void) do_syslog(SYSLOG_ACTION_CLOSE, NULL, 0, SYSLOG_FROM_PROC);
+	return 0;
+}
+
+static ssize_t kmsg_read(struct file *file, char __user *buf,
+			 size_t count, loff_t *ppos)
+{
+	if ((file->f_flags & O_NONBLOCK) &&
+	    !do_syslog(SYSLOG_ACTION_SIZE_UNREAD, NULL, 0, SYSLOG_FROM_PROC))
+		return -EAGAIN;
+	return do_syslog(SYSLOG_ACTION_READ, buf, count, SYSLOG_FROM_PROC);
+}
+
+static __poll_t kmsg_poll(struct file *file, poll_table *wait)
+{
+	poll_wait(file, &log_wait, wait);
+	if (do_syslog(SYSLOG_ACTION_SIZE_UNREAD, NULL, 0, SYSLOG_FROM_PROC))
+		return EPOLLIN | EPOLLRDNORM;
+	return 0;
+}
+
+
+static const struct proc_ops kmsg_proc_ops = {
+	.proc_flags	= PROC_ENTRY_PERMANENT,
+	.proc_read	= kmsg_read,
+	.proc_poll	= kmsg_poll,
+	.proc_open	= kmsg_open,
+	.proc_release	= kmsg_release,
+	.proc_lseek	= generic_file_llseek,
+};
+
+static int __init proc_kmsg_init(void)
+{
+	proc_create("kmsg", S_IRUSR, NULL, &kmsg_proc_ops);
+	return 0;
+}
+fs_initcall(proc_kmsg_init);
diff --git a/fs/proc/loadavg.c b/fs/proc/loadavg.c
new file mode 100644
index 000000000..817981e57
--- /dev/null
+++ b/fs/proc/loadavg.c
@@ -0,0 +1,37 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/fs.h>
+#include <linux/init.h>
+#include <linux/pid_namespace.h>
+#include <linux/proc_fs.h>
+#include <linux/sched.h>
+#include <linux/sched/loadavg.h>
+#include <linux/sched/stat.h>
+#include <linux/seq_file.h>
+#include <linux/seqlock.h>
+#include <linux/time.h>
+#include "internal.h"
+
+static int loadavg_proc_show(struct seq_file *m, void *v)
+{
+	unsigned long avnrun[3];
+
+	get_avenrun(avnrun, FIXED_1/200, 0);
+
+	seq_printf(m, "%lu.%02lu %lu.%02lu %lu.%02lu %u/%d %d\n",
+		LOAD_INT(avnrun[0]), LOAD_FRAC(avnrun[0]),
+		LOAD_INT(avnrun[1]), LOAD_FRAC(avnrun[1]),
+		LOAD_INT(avnrun[2]), LOAD_FRAC(avnrun[2]),
+		nr_running(), nr_threads,
+		idr_get_cursor(&task_active_pid_ns(current)->idr) - 1);
+	return 0;
+}
+
+static int __init proc_loadavg_init(void)
+{
+	struct proc_dir_entry *pde;
+
+	pde = proc_create_single("loadavg", 0, NULL, loadavg_proc_show);
+	pde_make_permanent(pde);
+	return 0;
+}
+fs_initcall(proc_loadavg_init);
diff --git a/fs/proc/meminfo.c b/fs/proc/meminfo.c
new file mode 100644
index 000000000..440960110
--- /dev/null
+++ b/fs/proc/meminfo.c
@@ -0,0 +1,173 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/fs.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/mm.h>
+#include <linux/hugetlb.h>
+#include <linux/mman.h>
+#include <linux/mmzone.h>
+#include <linux/proc_fs.h>
+#include <linux/percpu.h>
+#include <linux/seq_file.h>
+#include <linux/swap.h>
+#include <linux/vmstat.h>
+#include <linux/atomic.h>
+#include <linux/vmalloc.h>
+#ifdef CONFIG_CMA
+#include <linux/cma.h>
+#endif
+#include <asm/page.h>
+#include "internal.h"
+
+void __attribute__((weak)) arch_report_meminfo(struct seq_file *m)
+{
+}
+
+static void show_val_kb(struct seq_file *m, const char *s, unsigned long num)
+{
+	seq_put_decimal_ull_width(m, s, num << (PAGE_SHIFT - 10), 8);
+	seq_write(m, " kB\n", 4);
+}
+
+static int meminfo_proc_show(struct seq_file *m, void *v)
+{
+	struct sysinfo i;
+	unsigned long committed;
+	long cached;
+	long available;
+	unsigned long pages[NR_LRU_LISTS];
+	unsigned long sreclaimable, sunreclaim;
+	int lru;
+
+	si_meminfo(&i);
+	si_swapinfo(&i);
+	committed = vm_memory_committed();
+
+	cached = global_node_page_state(NR_FILE_PAGES) -
+			total_swapcache_pages() - i.bufferram;
+	if (cached < 0)
+		cached = 0;
+
+	for (lru = LRU_BASE; lru < NR_LRU_LISTS; lru++)
+		pages[lru] = global_node_page_state(NR_LRU_BASE + lru);
+
+	available = si_mem_available();
+	sreclaimable = global_node_page_state_pages(NR_SLAB_RECLAIMABLE_B);
+	sunreclaim = global_node_page_state_pages(NR_SLAB_UNRECLAIMABLE_B);
+
+	show_val_kb(m, "MemTotal:       ", i.totalram);
+	show_val_kb(m, "MemFree:        ", i.freeram);
+	show_val_kb(m, "MemAvailable:   ", available);
+	show_val_kb(m, "Buffers:        ", i.bufferram);
+	show_val_kb(m, "Cached:         ", cached);
+	show_val_kb(m, "SwapCached:     ", total_swapcache_pages());
+	show_val_kb(m, "Active:         ", pages[LRU_ACTIVE_ANON] +
+					   pages[LRU_ACTIVE_FILE]);
+	show_val_kb(m, "Inactive:       ", pages[LRU_INACTIVE_ANON] +
+					   pages[LRU_INACTIVE_FILE]);
+	show_val_kb(m, "Active(anon):   ", pages[LRU_ACTIVE_ANON]);
+	show_val_kb(m, "Inactive(anon): ", pages[LRU_INACTIVE_ANON]);
+	show_val_kb(m, "Active(file):   ", pages[LRU_ACTIVE_FILE]);
+	show_val_kb(m, "Inactive(file): ", pages[LRU_INACTIVE_FILE]);
+	show_val_kb(m, "Unevictable:    ", pages[LRU_UNEVICTABLE]);
+	show_val_kb(m, "Mlocked:        ", global_zone_page_state(NR_MLOCK));
+
+#ifdef CONFIG_HIGHMEM
+	show_val_kb(m, "HighTotal:      ", i.totalhigh);
+	show_val_kb(m, "HighFree:       ", i.freehigh);
+	show_val_kb(m, "LowTotal:       ", i.totalram - i.totalhigh);
+	show_val_kb(m, "LowFree:        ", i.freeram - i.freehigh);
+#endif
+
+#ifndef CONFIG_MMU
+	show_val_kb(m, "MmapCopy:       ",
+		    (unsigned long)atomic_long_read(&mmap_pages_allocated));
+#endif
+
+	show_val_kb(m, "SwapTotal:      ", i.totalswap);
+	show_val_kb(m, "SwapFree:       ", i.freeswap);
+#ifdef CONFIG_ZSWAP
+	seq_printf(m,  "Zswap:          %8lu kB\n",
+		   (unsigned long)(zswap_pool_total_size >> 10));
+	seq_printf(m,  "Zswapped:       %8lu kB\n",
+		   (unsigned long)atomic_read(&zswap_stored_pages) <<
+		   (PAGE_SHIFT - 10));
+#endif
+	show_val_kb(m, "Dirty:          ",
+		    global_node_page_state(NR_FILE_DIRTY));
+	show_val_kb(m, "Writeback:      ",
+		    global_node_page_state(NR_WRITEBACK));
+	show_val_kb(m, "AnonPages:      ",
+		    global_node_page_state(NR_ANON_MAPPED));
+	show_val_kb(m, "Mapped:         ",
+		    global_node_page_state(NR_FILE_MAPPED));
+	show_val_kb(m, "Shmem:          ", i.sharedram);
+	show_val_kb(m, "KReclaimable:   ", sreclaimable +
+		    global_node_page_state(NR_KERNEL_MISC_RECLAIMABLE));
+	show_val_kb(m, "Slab:           ", sreclaimable + sunreclaim);
+	show_val_kb(m, "SReclaimable:   ", sreclaimable);
+	show_val_kb(m, "SUnreclaim:     ", sunreclaim);
+	seq_printf(m, "KernelStack:    %8lu kB\n",
+		   global_node_page_state(NR_KERNEL_STACK_KB));
+#ifdef CONFIG_SHADOW_CALL_STACK
+	seq_printf(m, "ShadowCallStack:%8lu kB\n",
+		   global_node_page_state(NR_KERNEL_SCS_KB));
+#endif
+	show_val_kb(m, "PageTables:     ",
+		    global_node_page_state(NR_PAGETABLE));
+	show_val_kb(m, "SecPageTables:  ",
+		    global_node_page_state(NR_SECONDARY_PAGETABLE));
+
+	show_val_kb(m, "NFS_Unstable:   ", 0);
+	show_val_kb(m, "Bounce:         ",
+		    global_zone_page_state(NR_BOUNCE));
+	show_val_kb(m, "WritebackTmp:   ",
+		    global_node_page_state(NR_WRITEBACK_TEMP));
+	show_val_kb(m, "CommitLimit:    ", vm_commit_limit());
+	show_val_kb(m, "Committed_AS:   ", committed);
+	seq_printf(m, "VmallocTotal:   %8lu kB\n",
+		   (unsigned long)VMALLOC_TOTAL >> 10);
+	show_val_kb(m, "VmallocUsed:    ", vmalloc_nr_pages());
+	show_val_kb(m, "VmallocChunk:   ", 0ul);
+	show_val_kb(m, "Percpu:         ", pcpu_nr_pages());
+
+#ifdef CONFIG_MEMORY_FAILURE
+	seq_printf(m, "HardwareCorrupted: %5lu kB\n",
+		   atomic_long_read(&num_poisoned_pages) << (PAGE_SHIFT - 10));
+#endif
+
+#ifdef CONFIG_TRANSPARENT_HUGEPAGE
+	show_val_kb(m, "AnonHugePages:  ",
+		    global_node_page_state(NR_ANON_THPS));
+	show_val_kb(m, "ShmemHugePages: ",
+		    global_node_page_state(NR_SHMEM_THPS));
+	show_val_kb(m, "ShmemPmdMapped: ",
+		    global_node_page_state(NR_SHMEM_PMDMAPPED));
+	show_val_kb(m, "FileHugePages:  ",
+		    global_node_page_state(NR_FILE_THPS));
+	show_val_kb(m, "FilePmdMapped:  ",
+		    global_node_page_state(NR_FILE_PMDMAPPED));
+#endif
+
+#ifdef CONFIG_CMA
+	show_val_kb(m, "CmaTotal:       ", totalcma_pages);
+	show_val_kb(m, "CmaFree:        ",
+		    global_zone_page_state(NR_FREE_CMA_PAGES));
+#endif
+
+	hugetlb_report_meminfo(m);
+
+	arch_report_meminfo(m);
+
+	return 0;
+}
+
+static int __init proc_meminfo_init(void)
+{
+	struct proc_dir_entry *pde;
+
+	pde = proc_create_single("meminfo", 0, NULL, meminfo_proc_show);
+	pde_make_permanent(pde);
+	return 0;
+}
+fs_initcall(proc_meminfo_init);
diff --git a/fs/proc/namespaces.c b/fs/proc/namespaces.c
new file mode 100644
index 000000000..8e159fc78
--- /dev/null
+++ b/fs/proc/namespaces.c
@@ -0,0 +1,183 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/proc_fs.h>
+#include <linux/nsproxy.h>
+#include <linux/ptrace.h>
+#include <linux/namei.h>
+#include <linux/file.h>
+#include <linux/utsname.h>
+#include <net/net_namespace.h>
+#include <linux/ipc_namespace.h>
+#include <linux/pid_namespace.h>
+#include <linux/user_namespace.h>
+#include "internal.h"
+
+
+static const struct proc_ns_operations *ns_entries[] = {
+#ifdef CONFIG_NET_NS
+	&netns_operations,
+#endif
+#ifdef CONFIG_UTS_NS
+	&utsns_operations,
+#endif
+#ifdef CONFIG_IPC_NS
+	&ipcns_operations,
+#endif
+#ifdef CONFIG_PID_NS
+	&pidns_operations,
+	&pidns_for_children_operations,
+#endif
+#ifdef CONFIG_USER_NS
+	&userns_operations,
+#endif
+	&mntns_operations,
+#ifdef CONFIG_CGROUPS
+	&cgroupns_operations,
+#endif
+#ifdef CONFIG_TIME_NS
+	&timens_operations,
+	&timens_for_children_operations,
+#endif
+};
+
+static const char *proc_ns_get_link(struct dentry *dentry,
+				    struct inode *inode,
+				    struct delayed_call *done)
+{
+	const struct proc_ns_operations *ns_ops = PROC_I(inode)->ns_ops;
+	struct task_struct *task;
+	struct path ns_path;
+	int error = -EACCES;
+
+	if (!dentry)
+		return ERR_PTR(-ECHILD);
+
+	task = get_proc_task(inode);
+	if (!task)
+		return ERR_PTR(-EACCES);
+
+	if (!ptrace_may_access(task, PTRACE_MODE_READ_FSCREDS))
+		goto out;
+
+	error = ns_get_path(&ns_path, task, ns_ops);
+	if (error)
+		goto out;
+
+	error = nd_jump_link(&ns_path);
+out:
+	put_task_struct(task);
+	return ERR_PTR(error);
+}
+
+static int proc_ns_readlink(struct dentry *dentry, char __user *buffer, int buflen)
+{
+	struct inode *inode = d_inode(dentry);
+	const struct proc_ns_operations *ns_ops = PROC_I(inode)->ns_ops;
+	struct task_struct *task;
+	char name[50];
+	int res = -EACCES;
+
+	task = get_proc_task(inode);
+	if (!task)
+		return res;
+
+	if (ptrace_may_access(task, PTRACE_MODE_READ_FSCREDS)) {
+		res = ns_get_name(name, sizeof(name), task, ns_ops);
+		if (res >= 0)
+			res = readlink_copy(buffer, buflen, name);
+	}
+	put_task_struct(task);
+	return res;
+}
+
+static const struct inode_operations proc_ns_link_inode_operations = {
+	.readlink	= proc_ns_readlink,
+	.get_link	= proc_ns_get_link,
+	.setattr	= proc_setattr,
+};
+
+static struct dentry *proc_ns_instantiate(struct dentry *dentry,
+	struct task_struct *task, const void *ptr)
+{
+	const struct proc_ns_operations *ns_ops = ptr;
+	struct inode *inode;
+	struct proc_inode *ei;
+
+	inode = proc_pid_make_inode(dentry->d_sb, task, S_IFLNK | S_IRWXUGO);
+	if (!inode)
+		return ERR_PTR(-ENOENT);
+
+	ei = PROC_I(inode);
+	inode->i_op = &proc_ns_link_inode_operations;
+	ei->ns_ops = ns_ops;
+	pid_update_inode(task, inode);
+
+	d_set_d_op(dentry, &pid_dentry_operations);
+	return d_splice_alias(inode, dentry);
+}
+
+static int proc_ns_dir_readdir(struct file *file, struct dir_context *ctx)
+{
+	struct task_struct *task = get_proc_task(file_inode(file));
+	const struct proc_ns_operations **entry, **last;
+
+	if (!task)
+		return -ENOENT;
+
+	if (!dir_emit_dots(file, ctx))
+		goto out;
+	if (ctx->pos >= 2 + ARRAY_SIZE(ns_entries))
+		goto out;
+	entry = ns_entries + (ctx->pos - 2);
+	last = &ns_entries[ARRAY_SIZE(ns_entries) - 1];
+	while (entry <= last) {
+		const struct proc_ns_operations *ops = *entry;
+		if (!proc_fill_cache(file, ctx, ops->name, strlen(ops->name),
+				     proc_ns_instantiate, task, ops))
+			break;
+		ctx->pos++;
+		entry++;
+	}
+out:
+	put_task_struct(task);
+	return 0;
+}
+
+const struct file_operations proc_ns_dir_operations = {
+	.read		= generic_read_dir,
+	.iterate_shared	= proc_ns_dir_readdir,
+	.llseek		= generic_file_llseek,
+};
+
+static struct dentry *proc_ns_dir_lookup(struct inode *dir,
+				struct dentry *dentry, unsigned int flags)
+{
+	struct task_struct *task = get_proc_task(dir);
+	const struct proc_ns_operations **entry, **last;
+	unsigned int len = dentry->d_name.len;
+	struct dentry *res = ERR_PTR(-ENOENT);
+
+	if (!task)
+		goto out_no_task;
+
+	last = &ns_entries[ARRAY_SIZE(ns_entries)];
+	for (entry = ns_entries; entry < last; entry++) {
+		if (strlen((*entry)->name) != len)
+			continue;
+		if (!memcmp(dentry->d_name.name, (*entry)->name, len))
+			break;
+	}
+	if (entry == last)
+		goto out;
+
+	res = proc_ns_instantiate(dentry, task, *entry);
+out:
+	put_task_struct(task);
+out_no_task:
+	return res;
+}
+
+const struct inode_operations proc_ns_dir_inode_operations = {
+	.lookup		= proc_ns_dir_lookup,
+	.getattr	= pid_getattr,
+	.setattr	= proc_setattr,
+};
diff --git a/fs/proc/nommu.c b/fs/proc/nommu.c
new file mode 100644
index 000000000..4d3493579
--- /dev/null
+++ b/fs/proc/nommu.c
@@ -0,0 +1,116 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/* nommu.c: mmu-less memory info files
+ *
+ * Copyright (C) 2004 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ */
+
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/errno.h>
+#include <linux/time.h>
+#include <linux/kernel.h>
+#include <linux/string.h>
+#include <linux/mman.h>
+#include <linux/proc_fs.h>
+#include <linux/mm.h>
+#include <linux/mmzone.h>
+#include <linux/pagemap.h>
+#include <linux/swap.h>
+#include <linux/smp.h>
+#include <linux/seq_file.h>
+#include <linux/hugetlb.h>
+#include <linux/vmalloc.h>
+#include <asm/tlb.h>
+#include <asm/div64.h>
+#include "internal.h"
+
+/*
+ * display a single region to a sequenced file
+ */
+static int nommu_region_show(struct seq_file *m, struct vm_region *region)
+{
+	unsigned long ino = 0;
+	struct file *file;
+	dev_t dev = 0;
+	int flags;
+
+	flags = region->vm_flags;
+	file = region->vm_file;
+
+	if (file) {
+		struct inode *inode = file_inode(region->vm_file);
+		dev = inode->i_sb->s_dev;
+		ino = inode->i_ino;
+	}
+
+	seq_setwidth(m, 25 + sizeof(void *) * 6 - 1);
+	seq_printf(m,
+		   "%08lx-%08lx %c%c%c%c %08llx %02x:%02x %lu ",
+		   region->vm_start,
+		   region->vm_end,
+		   flags & VM_READ ? 'r' : '-',
+		   flags & VM_WRITE ? 'w' : '-',
+		   flags & VM_EXEC ? 'x' : '-',
+		   flags & VM_MAYSHARE ? flags & VM_SHARED ? 'S' : 's' : 'p',
+		   ((loff_t)region->vm_pgoff) << PAGE_SHIFT,
+		   MAJOR(dev), MINOR(dev), ino);
+
+	if (file) {
+		seq_pad(m, ' ');
+		seq_file_path(m, file, "");
+	}
+
+	seq_putc(m, '\n');
+	return 0;
+}
+
+/*
+ * display a list of all the REGIONs the kernel knows about
+ * - nommu kernels have a single flat list
+ */
+static int nommu_region_list_show(struct seq_file *m, void *_p)
+{
+	struct rb_node *p = _p;
+
+	return nommu_region_show(m, rb_entry(p, struct vm_region, vm_rb));
+}
+
+static void *nommu_region_list_start(struct seq_file *m, loff_t *_pos)
+{
+	struct rb_node *p;
+	loff_t pos = *_pos;
+
+	down_read(&nommu_region_sem);
+
+	for (p = rb_first(&nommu_region_tree); p; p = rb_next(p))
+		if (pos-- == 0)
+			return p;
+	return NULL;
+}
+
+static void nommu_region_list_stop(struct seq_file *m, void *v)
+{
+	up_read(&nommu_region_sem);
+}
+
+static void *nommu_region_list_next(struct seq_file *m, void *v, loff_t *pos)
+{
+	(*pos)++;
+	return rb_next((struct rb_node *) v);
+}
+
+static const struct seq_operations proc_nommu_region_list_seqop = {
+	.start	= nommu_region_list_start,
+	.next	= nommu_region_list_next,
+	.stop	= nommu_region_list_stop,
+	.show	= nommu_region_list_show
+};
+
+static int __init proc_nommu_init(void)
+{
+	proc_create_seq("maps", S_IRUGO, NULL, &proc_nommu_region_list_seqop);
+	return 0;
+}
+
+fs_initcall(proc_nommu_init);
diff --git a/fs/proc/page.c b/fs/proc/page.c
new file mode 100644
index 000000000..f2273b164
--- /dev/null
+++ b/fs/proc/page.c
@@ -0,0 +1,342 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/memblock.h>
+#include <linux/compiler.h>
+#include <linux/fs.h>
+#include <linux/init.h>
+#include <linux/ksm.h>
+#include <linux/mm.h>
+#include <linux/mmzone.h>
+#include <linux/huge_mm.h>
+#include <linux/proc_fs.h>
+#include <linux/seq_file.h>
+#include <linux/hugetlb.h>
+#include <linux/memremap.h>
+#include <linux/memcontrol.h>
+#include <linux/mmu_notifier.h>
+#include <linux/page_idle.h>
+#include <linux/kernel-page-flags.h>
+#include <linux/uaccess.h>
+#include "internal.h"
+
+#define KPMSIZE sizeof(u64)
+#define KPMMASK (KPMSIZE - 1)
+#define KPMBITS (KPMSIZE * BITS_PER_BYTE)
+
+static inline unsigned long get_max_dump_pfn(void)
+{
+#ifdef CONFIG_SPARSEMEM
+	/*
+	 * The memmap of early sections is completely populated and marked
+	 * online even if max_pfn does not fall on a section boundary -
+	 * pfn_to_online_page() will succeed on all pages. Allow inspecting
+	 * these memmaps.
+	 */
+	return round_up(max_pfn, PAGES_PER_SECTION);
+#else
+	return max_pfn;
+#endif
+}
+
+/* /proc/kpagecount - an array exposing page counts
+ *
+ * Each entry is a u64 representing the corresponding
+ * physical page count.
+ */
+static ssize_t kpagecount_read(struct file *file, char __user *buf,
+			     size_t count, loff_t *ppos)
+{
+	const unsigned long max_dump_pfn = get_max_dump_pfn();
+	u64 __user *out = (u64 __user *)buf;
+	struct page *ppage;
+	unsigned long src = *ppos;
+	unsigned long pfn;
+	ssize_t ret = 0;
+	u64 pcount;
+
+	pfn = src / KPMSIZE;
+	if (src & KPMMASK || count & KPMMASK)
+		return -EINVAL;
+	if (src >= max_dump_pfn * KPMSIZE)
+		return 0;
+	count = min_t(unsigned long, count, (max_dump_pfn * KPMSIZE) - src);
+
+	while (count > 0) {
+		/*
+		 * TODO: ZONE_DEVICE support requires to identify
+		 * memmaps that were actually initialized.
+		 */
+		ppage = pfn_to_online_page(pfn);
+
+		if (!ppage || PageSlab(ppage) || page_has_type(ppage))
+			pcount = 0;
+		else
+			pcount = page_mapcount(ppage);
+
+		if (put_user(pcount, out)) {
+			ret = -EFAULT;
+			break;
+		}
+
+		pfn++;
+		out++;
+		count -= KPMSIZE;
+
+		cond_resched();
+	}
+
+	*ppos += (char __user *)out - buf;
+	if (!ret)
+		ret = (char __user *)out - buf;
+	return ret;
+}
+
+static const struct proc_ops kpagecount_proc_ops = {
+	.proc_flags	= PROC_ENTRY_PERMANENT,
+	.proc_lseek	= mem_lseek,
+	.proc_read	= kpagecount_read,
+};
+
+/* /proc/kpageflags - an array exposing page flags
+ *
+ * Each entry is a u64 representing the corresponding
+ * physical page flags.
+ */
+
+static inline u64 kpf_copy_bit(u64 kflags, int ubit, int kbit)
+{
+	return ((kflags >> kbit) & 1) << ubit;
+}
+
+u64 stable_page_flags(struct page *page)
+{
+	u64 k;
+	u64 u;
+
+	/*
+	 * pseudo flag: KPF_NOPAGE
+	 * it differentiates a memory hole from a page with no flags
+	 */
+	if (!page)
+		return 1 << KPF_NOPAGE;
+
+	k = page->flags;
+	u = 0;
+
+	/*
+	 * pseudo flags for the well known (anonymous) memory mapped pages
+	 *
+	 * Note that page->_mapcount is overloaded in SLOB/SLUB/SLQB, so the
+	 * simple test in page_mapped() is not enough.
+	 */
+	if (!PageSlab(page) && page_mapped(page))
+		u |= 1 << KPF_MMAP;
+	if (PageAnon(page))
+		u |= 1 << KPF_ANON;
+	if (PageKsm(page))
+		u |= 1 << KPF_KSM;
+
+	/*
+	 * compound pages: export both head/tail info
+	 * they together define a compound page's start/end pos and order
+	 */
+	if (PageHead(page))
+		u |= 1 << KPF_COMPOUND_HEAD;
+	if (PageTail(page))
+		u |= 1 << KPF_COMPOUND_TAIL;
+	if (PageHuge(page))
+		u |= 1 << KPF_HUGE;
+	/*
+	 * PageTransCompound can be true for non-huge compound pages (slab
+	 * pages or pages allocated by drivers with __GFP_COMP) because it
+	 * just checks PG_head/PG_tail, so we need to check PageLRU/PageAnon
+	 * to make sure a given page is a thp, not a non-huge compound page.
+	 */
+	else if (PageTransCompound(page)) {
+		struct page *head = compound_head(page);
+
+		if (PageLRU(head) || PageAnon(head))
+			u |= 1 << KPF_THP;
+		else if (is_huge_zero_page(head)) {
+			u |= 1 << KPF_ZERO_PAGE;
+			u |= 1 << KPF_THP;
+		}
+	} else if (is_zero_pfn(page_to_pfn(page)))
+		u |= 1 << KPF_ZERO_PAGE;
+
+
+	/*
+	 * Caveats on high order pages: page->_refcount will only be set
+	 * -1 on the head page; SLUB/SLQB do the same for PG_slab;
+	 * SLOB won't set PG_slab at all on compound pages.
+	 */
+	if (PageBuddy(page))
+		u |= 1 << KPF_BUDDY;
+	else if (page_count(page) == 0 && is_free_buddy_page(page))
+		u |= 1 << KPF_BUDDY;
+
+	if (PageOffline(page))
+		u |= 1 << KPF_OFFLINE;
+	if (PageTable(page))
+		u |= 1 << KPF_PGTABLE;
+
+	if (page_is_idle(page))
+		u |= 1 << KPF_IDLE;
+
+	u |= kpf_copy_bit(k, KPF_LOCKED,	PG_locked);
+
+	u |= kpf_copy_bit(k, KPF_SLAB,		PG_slab);
+	if (PageTail(page) && PageSlab(compound_head(page)))
+		u |= 1 << KPF_SLAB;
+
+	u |= kpf_copy_bit(k, KPF_ERROR,		PG_error);
+	u |= kpf_copy_bit(k, KPF_DIRTY,		PG_dirty);
+	u |= kpf_copy_bit(k, KPF_UPTODATE,	PG_uptodate);
+	u |= kpf_copy_bit(k, KPF_WRITEBACK,	PG_writeback);
+
+	u |= kpf_copy_bit(k, KPF_LRU,		PG_lru);
+	u |= kpf_copy_bit(k, KPF_REFERENCED,	PG_referenced);
+	u |= kpf_copy_bit(k, KPF_ACTIVE,	PG_active);
+	u |= kpf_copy_bit(k, KPF_RECLAIM,	PG_reclaim);
+
+	if (PageSwapCache(page))
+		u |= 1 << KPF_SWAPCACHE;
+	u |= kpf_copy_bit(k, KPF_SWAPBACKED,	PG_swapbacked);
+
+	u |= kpf_copy_bit(k, KPF_UNEVICTABLE,	PG_unevictable);
+	u |= kpf_copy_bit(k, KPF_MLOCKED,	PG_mlocked);
+
+#ifdef CONFIG_MEMORY_FAILURE
+	u |= kpf_copy_bit(k, KPF_HWPOISON,	PG_hwpoison);
+#endif
+
+#ifdef CONFIG_ARCH_USES_PG_UNCACHED
+	u |= kpf_copy_bit(k, KPF_UNCACHED,	PG_uncached);
+#endif
+
+	u |= kpf_copy_bit(k, KPF_RESERVED,	PG_reserved);
+	u |= kpf_copy_bit(k, KPF_MAPPEDTODISK,	PG_mappedtodisk);
+	u |= kpf_copy_bit(k, KPF_PRIVATE,	PG_private);
+	u |= kpf_copy_bit(k, KPF_PRIVATE_2,	PG_private_2);
+	u |= kpf_copy_bit(k, KPF_OWNER_PRIVATE,	PG_owner_priv_1);
+	u |= kpf_copy_bit(k, KPF_ARCH,		PG_arch_1);
+#ifdef CONFIG_64BIT
+	u |= kpf_copy_bit(k, KPF_ARCH_2,	PG_arch_2);
+#endif
+
+	return u;
+};
+
+static ssize_t kpageflags_read(struct file *file, char __user *buf,
+			     size_t count, loff_t *ppos)
+{
+	const unsigned long max_dump_pfn = get_max_dump_pfn();
+	u64 __user *out = (u64 __user *)buf;
+	struct page *ppage;
+	unsigned long src = *ppos;
+	unsigned long pfn;
+	ssize_t ret = 0;
+
+	pfn = src / KPMSIZE;
+	if (src & KPMMASK || count & KPMMASK)
+		return -EINVAL;
+	if (src >= max_dump_pfn * KPMSIZE)
+		return 0;
+	count = min_t(unsigned long, count, (max_dump_pfn * KPMSIZE) - src);
+
+	while (count > 0) {
+		/*
+		 * TODO: ZONE_DEVICE support requires to identify
+		 * memmaps that were actually initialized.
+		 */
+		ppage = pfn_to_online_page(pfn);
+
+		if (put_user(stable_page_flags(ppage), out)) {
+			ret = -EFAULT;
+			break;
+		}
+
+		pfn++;
+		out++;
+		count -= KPMSIZE;
+
+		cond_resched();
+	}
+
+	*ppos += (char __user *)out - buf;
+	if (!ret)
+		ret = (char __user *)out - buf;
+	return ret;
+}
+
+static const struct proc_ops kpageflags_proc_ops = {
+	.proc_flags	= PROC_ENTRY_PERMANENT,
+	.proc_lseek	= mem_lseek,
+	.proc_read	= kpageflags_read,
+};
+
+#ifdef CONFIG_MEMCG
+static ssize_t kpagecgroup_read(struct file *file, char __user *buf,
+				size_t count, loff_t *ppos)
+{
+	const unsigned long max_dump_pfn = get_max_dump_pfn();
+	u64 __user *out = (u64 __user *)buf;
+	struct page *ppage;
+	unsigned long src = *ppos;
+	unsigned long pfn;
+	ssize_t ret = 0;
+	u64 ino;
+
+	pfn = src / KPMSIZE;
+	if (src & KPMMASK || count & KPMMASK)
+		return -EINVAL;
+	if (src >= max_dump_pfn * KPMSIZE)
+		return 0;
+	count = min_t(unsigned long, count, (max_dump_pfn * KPMSIZE) - src);
+
+	while (count > 0) {
+		/*
+		 * TODO: ZONE_DEVICE support requires to identify
+		 * memmaps that were actually initialized.
+		 */
+		ppage = pfn_to_online_page(pfn);
+
+		if (ppage)
+			ino = page_cgroup_ino(ppage);
+		else
+			ino = 0;
+
+		if (put_user(ino, out)) {
+			ret = -EFAULT;
+			break;
+		}
+
+		pfn++;
+		out++;
+		count -= KPMSIZE;
+
+		cond_resched();
+	}
+
+	*ppos += (char __user *)out - buf;
+	if (!ret)
+		ret = (char __user *)out - buf;
+	return ret;
+}
+
+static const struct proc_ops kpagecgroup_proc_ops = {
+	.proc_flags	= PROC_ENTRY_PERMANENT,
+	.proc_lseek	= mem_lseek,
+	.proc_read	= kpagecgroup_read,
+};
+#endif /* CONFIG_MEMCG */
+
+static int __init proc_page_init(void)
+{
+	proc_create("kpagecount", S_IRUSR, NULL, &kpagecount_proc_ops);
+	proc_create("kpageflags", S_IRUSR, NULL, &kpageflags_proc_ops);
+#ifdef CONFIG_MEMCG
+	proc_create("kpagecgroup", S_IRUSR, NULL, &kpagecgroup_proc_ops);
+#endif
+	return 0;
+}
+fs_initcall(proc_page_init);
diff --git a/fs/proc/proc_net.c b/fs/proc/proc_net.c
new file mode 100644
index 000000000..856839b8a
--- /dev/null
+++ b/fs/proc/proc_net.c
@@ -0,0 +1,416 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ *  linux/fs/proc/net.c
+ *
+ *  Copyright (C) 2007
+ *
+ *  Author: Eric Biederman <ebiederm@xmission.com>
+ *
+ *  proc net directory handling functions
+ */
+#include <linux/errno.h>
+#include <linux/time.h>
+#include <linux/proc_fs.h>
+#include <linux/stat.h>
+#include <linux/slab.h>
+#include <linux/init.h>
+#include <linux/sched.h>
+#include <linux/sched/task.h>
+#include <linux/module.h>
+#include <linux/bitops.h>
+#include <linux/mount.h>
+#include <linux/nsproxy.h>
+#include <linux/uidgid.h>
+#include <net/net_namespace.h>
+#include <linux/seq_file.h>
+
+#include "internal.h"
+
+static inline struct net *PDE_NET(struct proc_dir_entry *pde)
+{
+	return pde->parent->data;
+}
+
+static struct net *get_proc_net(const struct inode *inode)
+{
+	return maybe_get_net(PDE_NET(PDE(inode)));
+}
+
+static int seq_open_net(struct inode *inode, struct file *file)
+{
+	unsigned int state_size = PDE(inode)->state_size;
+	struct seq_net_private *p;
+	struct net *net;
+
+	WARN_ON_ONCE(state_size < sizeof(*p));
+
+	if (file->f_mode & FMODE_WRITE && !PDE(inode)->write)
+		return -EACCES;
+
+	net = get_proc_net(inode);
+	if (!net)
+		return -ENXIO;
+
+	p = __seq_open_private(file, PDE(inode)->seq_ops, state_size);
+	if (!p) {
+		put_net(net);
+		return -ENOMEM;
+	}
+#ifdef CONFIG_NET_NS
+	p->net = net;
+	netns_tracker_alloc(net, &p->ns_tracker, GFP_KERNEL);
+#endif
+	return 0;
+}
+
+static void seq_file_net_put_net(struct seq_file *seq)
+{
+#ifdef CONFIG_NET_NS
+	struct seq_net_private *priv = seq->private;
+
+	put_net_track(priv->net, &priv->ns_tracker);
+#else
+	put_net(&init_net);
+#endif
+}
+
+static int seq_release_net(struct inode *ino, struct file *f)
+{
+	struct seq_file *seq = f->private_data;
+
+	seq_file_net_put_net(seq);
+	seq_release_private(ino, f);
+	return 0;
+}
+
+static const struct proc_ops proc_net_seq_ops = {
+	.proc_open	= seq_open_net,
+	.proc_read	= seq_read,
+	.proc_write	= proc_simple_write,
+	.proc_lseek	= seq_lseek,
+	.proc_release	= seq_release_net,
+};
+
+int bpf_iter_init_seq_net(void *priv_data, struct bpf_iter_aux_info *aux)
+{
+#ifdef CONFIG_NET_NS
+	struct seq_net_private *p = priv_data;
+
+	p->net = get_net_track(current->nsproxy->net_ns, &p->ns_tracker,
+			       GFP_KERNEL);
+#endif
+	return 0;
+}
+
+void bpf_iter_fini_seq_net(void *priv_data)
+{
+#ifdef CONFIG_NET_NS
+	struct seq_net_private *p = priv_data;
+
+	put_net_track(p->net, &p->ns_tracker);
+#endif
+}
+
+struct proc_dir_entry *proc_create_net_data(const char *name, umode_t mode,
+		struct proc_dir_entry *parent, const struct seq_operations *ops,
+		unsigned int state_size, void *data)
+{
+	struct proc_dir_entry *p;
+
+	p = proc_create_reg(name, mode, &parent, data);
+	if (!p)
+		return NULL;
+	pde_force_lookup(p);
+	p->proc_ops = &proc_net_seq_ops;
+	p->seq_ops = ops;
+	p->state_size = state_size;
+	return proc_register(parent, p);
+}
+EXPORT_SYMBOL_GPL(proc_create_net_data);
+
+/**
+ * proc_create_net_data_write - Create a writable net_ns-specific proc file
+ * @name: The name of the file.
+ * @mode: The file's access mode.
+ * @parent: The parent directory in which to create.
+ * @ops: The seq_file ops with which to read the file.
+ * @write: The write method with which to 'modify' the file.
+ * @data: Data for retrieval by pde_data().
+ *
+ * Create a network namespaced proc file in the @parent directory with the
+ * specified @name and @mode that allows reading of a file that displays a
+ * series of elements and also provides for the file accepting writes that have
+ * some arbitrary effect.
+ *
+ * The functions in the @ops table are used to iterate over items to be
+ * presented and extract the readable content using the seq_file interface.
+ *
+ * The @write function is called with the data copied into a kernel space
+ * scratch buffer and has a NUL appended for convenience.  The buffer may be
+ * modified by the @write function.  @write should return 0 on success.
+ *
+ * The @data value is accessible from the @show and @write functions by calling
+ * pde_data() on the file inode.  The network namespace must be accessed by
+ * calling seq_file_net() on the seq_file struct.
+ */
+struct proc_dir_entry *proc_create_net_data_write(const char *name, umode_t mode,
+						  struct proc_dir_entry *parent,
+						  const struct seq_operations *ops,
+						  proc_write_t write,
+						  unsigned int state_size, void *data)
+{
+	struct proc_dir_entry *p;
+
+	p = proc_create_reg(name, mode, &parent, data);
+	if (!p)
+		return NULL;
+	pde_force_lookup(p);
+	p->proc_ops = &proc_net_seq_ops;
+	p->seq_ops = ops;
+	p->state_size = state_size;
+	p->write = write;
+	return proc_register(parent, p);
+}
+EXPORT_SYMBOL_GPL(proc_create_net_data_write);
+
+static int single_open_net(struct inode *inode, struct file *file)
+{
+	struct proc_dir_entry *de = PDE(inode);
+	struct net *net;
+	int err;
+
+	net = get_proc_net(inode);
+	if (!net)
+		return -ENXIO;
+
+	err = single_open(file, de->single_show, net);
+	if (err)
+		put_net(net);
+	return err;
+}
+
+static int single_release_net(struct inode *ino, struct file *f)
+{
+	struct seq_file *seq = f->private_data;
+	put_net(seq->private);
+	return single_release(ino, f);
+}
+
+static const struct proc_ops proc_net_single_ops = {
+	.proc_open	= single_open_net,
+	.proc_read	= seq_read,
+	.proc_write	= proc_simple_write,
+	.proc_lseek	= seq_lseek,
+	.proc_release	= single_release_net,
+};
+
+struct proc_dir_entry *proc_create_net_single(const char *name, umode_t mode,
+		struct proc_dir_entry *parent,
+		int (*show)(struct seq_file *, void *), void *data)
+{
+	struct proc_dir_entry *p;
+
+	p = proc_create_reg(name, mode, &parent, data);
+	if (!p)
+		return NULL;
+	pde_force_lookup(p);
+	p->proc_ops = &proc_net_single_ops;
+	p->single_show = show;
+	return proc_register(parent, p);
+}
+EXPORT_SYMBOL_GPL(proc_create_net_single);
+
+/**
+ * proc_create_net_single_write - Create a writable net_ns-specific proc file
+ * @name: The name of the file.
+ * @mode: The file's access mode.
+ * @parent: The parent directory in which to create.
+ * @show: The seqfile show method with which to read the file.
+ * @write: The write method with which to 'modify' the file.
+ * @data: Data for retrieval by pde_data().
+ *
+ * Create a network-namespaced proc file in the @parent directory with the
+ * specified @name and @mode that allows reading of a file that displays a
+ * single element rather than a series and also provides for the file accepting
+ * writes that have some arbitrary effect.
+ *
+ * The @show function is called to extract the readable content via the
+ * seq_file interface.
+ *
+ * The @write function is called with the data copied into a kernel space
+ * scratch buffer and has a NUL appended for convenience.  The buffer may be
+ * modified by the @write function.  @write should return 0 on success.
+ *
+ * The @data value is accessible from the @show and @write functions by calling
+ * pde_data() on the file inode.  The network namespace must be accessed by
+ * calling seq_file_single_net() on the seq_file struct.
+ */
+struct proc_dir_entry *proc_create_net_single_write(const char *name, umode_t mode,
+						    struct proc_dir_entry *parent,
+						    int (*show)(struct seq_file *, void *),
+						    proc_write_t write,
+						    void *data)
+{
+	struct proc_dir_entry *p;
+
+	p = proc_create_reg(name, mode, &parent, data);
+	if (!p)
+		return NULL;
+	pde_force_lookup(p);
+	p->proc_ops = &proc_net_single_ops;
+	p->single_show = show;
+	p->write = write;
+	return proc_register(parent, p);
+}
+EXPORT_SYMBOL_GPL(proc_create_net_single_write);
+
+static struct net *get_proc_task_net(struct inode *dir)
+{
+	struct task_struct *task;
+	struct nsproxy *ns;
+	struct net *net = NULL;
+
+	rcu_read_lock();
+	task = pid_task(proc_pid(dir), PIDTYPE_PID);
+	if (task != NULL) {
+		task_lock(task);
+		ns = task->nsproxy;
+		if (ns != NULL)
+			net = get_net(ns->net_ns);
+		task_unlock(task);
+	}
+	rcu_read_unlock();
+
+	return net;
+}
+
+static struct dentry *proc_tgid_net_lookup(struct inode *dir,
+		struct dentry *dentry, unsigned int flags)
+{
+	struct dentry *de;
+	struct net *net;
+
+	de = ERR_PTR(-ENOENT);
+	net = get_proc_task_net(dir);
+	if (net != NULL) {
+		de = proc_lookup_de(dir, dentry, net->proc_net);
+		put_net(net);
+	}
+	return de;
+}
+
+static int proc_tgid_net_getattr(struct user_namespace *mnt_userns,
+				 const struct path *path, struct kstat *stat,
+				 u32 request_mask, unsigned int query_flags)
+{
+	struct inode *inode = d_inode(path->dentry);
+	struct net *net;
+
+	net = get_proc_task_net(inode);
+
+	generic_fillattr(&init_user_ns, inode, stat);
+
+	if (net != NULL) {
+		stat->nlink = net->proc_net->nlink;
+		put_net(net);
+	}
+
+	return 0;
+}
+
+const struct inode_operations proc_net_inode_operations = {
+	.lookup		= proc_tgid_net_lookup,
+	.getattr	= proc_tgid_net_getattr,
+};
+
+static int proc_tgid_net_readdir(struct file *file, struct dir_context *ctx)
+{
+	int ret;
+	struct net *net;
+
+	ret = -EINVAL;
+	net = get_proc_task_net(file_inode(file));
+	if (net != NULL) {
+		ret = proc_readdir_de(file, ctx, net->proc_net);
+		put_net(net);
+	}
+	return ret;
+}
+
+const struct file_operations proc_net_operations = {
+	.llseek		= generic_file_llseek,
+	.read		= generic_read_dir,
+	.iterate_shared	= proc_tgid_net_readdir,
+};
+
+static __net_init int proc_net_ns_init(struct net *net)
+{
+	struct proc_dir_entry *netd, *net_statd;
+	kuid_t uid;
+	kgid_t gid;
+	int err;
+
+	/*
+	 * This PDE acts only as an anchor for /proc/${pid}/net hierarchy.
+	 * Corresponding inode (PDE(inode) == net->proc_net) is never
+	 * instantiated therefore blanket zeroing is fine.
+	 * net->proc_net_stat inode is instantiated normally.
+	 */
+	err = -ENOMEM;
+	netd = kmem_cache_zalloc(proc_dir_entry_cache, GFP_KERNEL);
+	if (!netd)
+		goto out;
+
+	netd->subdir = RB_ROOT;
+	netd->data = net;
+	netd->nlink = 2;
+	netd->namelen = 3;
+	netd->parent = &proc_root;
+	netd->name = netd->inline_name;
+	memcpy(netd->name, "net", 4);
+
+	uid = make_kuid(net->user_ns, 0);
+	if (!uid_valid(uid))
+		uid = netd->uid;
+
+	gid = make_kgid(net->user_ns, 0);
+	if (!gid_valid(gid))
+		gid = netd->gid;
+
+	proc_set_user(netd, uid, gid);
+
+	/* Seed dentry revalidation for /proc/${pid}/net */
+	pde_force_lookup(netd);
+
+	err = -EEXIST;
+	net_statd = proc_net_mkdir(net, "stat", netd);
+	if (!net_statd)
+		goto free_net;
+
+	net->proc_net = netd;
+	net->proc_net_stat = net_statd;
+	return 0;
+
+free_net:
+	pde_free(netd);
+out:
+	return err;
+}
+
+static __net_exit void proc_net_ns_exit(struct net *net)
+{
+	remove_proc_entry("stat", net->proc_net);
+	pde_free(net->proc_net);
+}
+
+static struct pernet_operations __net_initdata proc_net_ns_ops = {
+	.init = proc_net_ns_init,
+	.exit = proc_net_ns_exit,
+};
+
+int __init proc_net_init(void)
+{
+	proc_symlink("net", NULL, "self/net");
+
+	return register_pernet_subsys(&proc_net_ns_ops);
+}
diff --git a/fs/proc/proc_sysctl.c b/fs/proc/proc_sysctl.c
new file mode 100644
index 000000000..4a4c04a3b
--- /dev/null
+++ b/fs/proc/proc_sysctl.c
@@ -0,0 +1,1951 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * /proc/sys support
+ */
+#include <linux/init.h>
+#include <linux/sysctl.h>
+#include <linux/poll.h>
+#include <linux/proc_fs.h>
+#include <linux/printk.h>
+#include <linux/security.h>
+#include <linux/sched.h>
+#include <linux/cred.h>
+#include <linux/namei.h>
+#include <linux/mm.h>
+#include <linux/uio.h>
+#include <linux/module.h>
+#include <linux/bpf-cgroup.h>
+#include <linux/mount.h>
+#include <linux/kmemleak.h>
+#include "internal.h"
+
+#define list_for_each_table_entry(entry, table) \
+	for ((entry) = (table); (entry)->procname; (entry)++)
+
+static const struct dentry_operations proc_sys_dentry_operations;
+static const struct file_operations proc_sys_file_operations;
+static const struct inode_operations proc_sys_inode_operations;
+static const struct file_operations proc_sys_dir_file_operations;
+static const struct inode_operations proc_sys_dir_operations;
+
+/* Support for permanently empty directories */
+
+struct ctl_table sysctl_mount_point[] = {
+	{ }
+};
+
+/**
+ * register_sysctl_mount_point() - registers a sysctl mount point
+ * @path: path for the mount point
+ *
+ * Used to create a permanently empty directory to serve as mount point.
+ * There are some subtle but important permission checks this allows in the
+ * case of unprivileged mounts.
+ */
+struct ctl_table_header *register_sysctl_mount_point(const char *path)
+{
+	return register_sysctl(path, sysctl_mount_point);
+}
+EXPORT_SYMBOL(register_sysctl_mount_point);
+
+static bool is_empty_dir(struct ctl_table_header *head)
+{
+	return head->ctl_table[0].child == sysctl_mount_point;
+}
+
+static void set_empty_dir(struct ctl_dir *dir)
+{
+	dir->header.ctl_table[0].child = sysctl_mount_point;
+}
+
+static void clear_empty_dir(struct ctl_dir *dir)
+
+{
+	dir->header.ctl_table[0].child = NULL;
+}
+
+void proc_sys_poll_notify(struct ctl_table_poll *poll)
+{
+	if (!poll)
+		return;
+
+	atomic_inc(&poll->event);
+	wake_up_interruptible(&poll->wait);
+}
+
+static struct ctl_table root_table[] = {
+	{
+		.procname = "",
+		.mode = S_IFDIR|S_IRUGO|S_IXUGO,
+	},
+	{ }
+};
+static struct ctl_table_root sysctl_table_root = {
+	.default_set.dir.header = {
+		{{.count = 1,
+		  .nreg = 1,
+		  .ctl_table = root_table }},
+		.ctl_table_arg = root_table,
+		.root = &sysctl_table_root,
+		.set = &sysctl_table_root.default_set,
+	},
+};
+
+static DEFINE_SPINLOCK(sysctl_lock);
+
+static void drop_sysctl_table(struct ctl_table_header *header);
+static int sysctl_follow_link(struct ctl_table_header **phead,
+	struct ctl_table **pentry);
+static int insert_links(struct ctl_table_header *head);
+static void put_links(struct ctl_table_header *header);
+
+static void sysctl_print_dir(struct ctl_dir *dir)
+{
+	if (dir->header.parent)
+		sysctl_print_dir(dir->header.parent);
+	pr_cont("%s/", dir->header.ctl_table[0].procname);
+}
+
+static int namecmp(const char *name1, int len1, const char *name2, int len2)
+{
+	int cmp;
+
+	cmp = memcmp(name1, name2, min(len1, len2));
+	if (cmp == 0)
+		cmp = len1 - len2;
+	return cmp;
+}
+
+/* Called under sysctl_lock */
+static struct ctl_table *find_entry(struct ctl_table_header **phead,
+	struct ctl_dir *dir, const char *name, int namelen)
+{
+	struct ctl_table_header *head;
+	struct ctl_table *entry;
+	struct rb_node *node = dir->root.rb_node;
+
+	while (node)
+	{
+		struct ctl_node *ctl_node;
+		const char *procname;
+		int cmp;
+
+		ctl_node = rb_entry(node, struct ctl_node, node);
+		head = ctl_node->header;
+		entry = &head->ctl_table[ctl_node - head->node];
+		procname = entry->procname;
+
+		cmp = namecmp(name, namelen, procname, strlen(procname));
+		if (cmp < 0)
+			node = node->rb_left;
+		else if (cmp > 0)
+			node = node->rb_right;
+		else {
+			*phead = head;
+			return entry;
+		}
+	}
+	return NULL;
+}
+
+static int insert_entry(struct ctl_table_header *head, struct ctl_table *entry)
+{
+	struct rb_node *node = &head->node[entry - head->ctl_table].node;
+	struct rb_node **p = &head->parent->root.rb_node;
+	struct rb_node *parent = NULL;
+	const char *name = entry->procname;
+	int namelen = strlen(name);
+
+	while (*p) {
+		struct ctl_table_header *parent_head;
+		struct ctl_table *parent_entry;
+		struct ctl_node *parent_node;
+		const char *parent_name;
+		int cmp;
+
+		parent = *p;
+		parent_node = rb_entry(parent, struct ctl_node, node);
+		parent_head = parent_node->header;
+		parent_entry = &parent_head->ctl_table[parent_node - parent_head->node];
+		parent_name = parent_entry->procname;
+
+		cmp = namecmp(name, namelen, parent_name, strlen(parent_name));
+		if (cmp < 0)
+			p = &(*p)->rb_left;
+		else if (cmp > 0)
+			p = &(*p)->rb_right;
+		else {
+			pr_err("sysctl duplicate entry: ");
+			sysctl_print_dir(head->parent);
+			pr_cont("%s\n", entry->procname);
+			return -EEXIST;
+		}
+	}
+
+	rb_link_node(node, parent, p);
+	rb_insert_color(node, &head->parent->root);
+	return 0;
+}
+
+static void erase_entry(struct ctl_table_header *head, struct ctl_table *entry)
+{
+	struct rb_node *node = &head->node[entry - head->ctl_table].node;
+
+	rb_erase(node, &head->parent->root);
+}
+
+static void init_header(struct ctl_table_header *head,
+	struct ctl_table_root *root, struct ctl_table_set *set,
+	struct ctl_node *node, struct ctl_table *table)
+{
+	head->ctl_table = table;
+	head->ctl_table_arg = table;
+	head->used = 0;
+	head->count = 1;
+	head->nreg = 1;
+	head->unregistering = NULL;
+	head->root = root;
+	head->set = set;
+	head->parent = NULL;
+	head->node = node;
+	INIT_HLIST_HEAD(&head->inodes);
+	if (node) {
+		struct ctl_table *entry;
+
+		list_for_each_table_entry(entry, table) {
+			node->header = head;
+			node++;
+		}
+	}
+}
+
+static void erase_header(struct ctl_table_header *head)
+{
+	struct ctl_table *entry;
+
+	list_for_each_table_entry(entry, head->ctl_table)
+		erase_entry(head, entry);
+}
+
+static int insert_header(struct ctl_dir *dir, struct ctl_table_header *header)
+{
+	struct ctl_table *entry;
+	int err;
+
+	/* Is this a permanently empty directory? */
+	if (is_empty_dir(&dir->header))
+		return -EROFS;
+
+	/* Am I creating a permanently empty directory? */
+	if (header->ctl_table == sysctl_mount_point) {
+		if (!RB_EMPTY_ROOT(&dir->root))
+			return -EINVAL;
+		set_empty_dir(dir);
+	}
+
+	dir->header.nreg++;
+	header->parent = dir;
+	err = insert_links(header);
+	if (err)
+		goto fail_links;
+	list_for_each_table_entry(entry, header->ctl_table) {
+		err = insert_entry(header, entry);
+		if (err)
+			goto fail;
+	}
+	return 0;
+fail:
+	erase_header(header);
+	put_links(header);
+fail_links:
+	if (header->ctl_table == sysctl_mount_point)
+		clear_empty_dir(dir);
+	header->parent = NULL;
+	drop_sysctl_table(&dir->header);
+	return err;
+}
+
+/* called under sysctl_lock */
+static int use_table(struct ctl_table_header *p)
+{
+	if (unlikely(p->unregistering))
+		return 0;
+	p->used++;
+	return 1;
+}
+
+/* called under sysctl_lock */
+static void unuse_table(struct ctl_table_header *p)
+{
+	if (!--p->used)
+		if (unlikely(p->unregistering))
+			complete(p->unregistering);
+}
+
+static void proc_sys_invalidate_dcache(struct ctl_table_header *head)
+{
+	proc_invalidate_siblings_dcache(&head->inodes, &sysctl_lock);
+}
+
+/* called under sysctl_lock, will reacquire if has to wait */
+static void start_unregistering(struct ctl_table_header *p)
+{
+	/*
+	 * if p->used is 0, nobody will ever touch that entry again;
+	 * we'll eliminate all paths to it before dropping sysctl_lock
+	 */
+	if (unlikely(p->used)) {
+		struct completion wait;
+		init_completion(&wait);
+		p->unregistering = &wait;
+		spin_unlock(&sysctl_lock);
+		wait_for_completion(&wait);
+	} else {
+		/* anything non-NULL; we'll never dereference it */
+		p->unregistering = ERR_PTR(-EINVAL);
+		spin_unlock(&sysctl_lock);
+	}
+	/*
+	 * Invalidate dentries for unregistered sysctls: namespaced sysctls
+	 * can have duplicate names and contaminate dcache very badly.
+	 */
+	proc_sys_invalidate_dcache(p);
+	/*
+	 * do not remove from the list until nobody holds it; walking the
+	 * list in do_sysctl() relies on that.
+	 */
+	spin_lock(&sysctl_lock);
+	erase_header(p);
+}
+
+static struct ctl_table_header *sysctl_head_grab(struct ctl_table_header *head)
+{
+	BUG_ON(!head);
+	spin_lock(&sysctl_lock);
+	if (!use_table(head))
+		head = ERR_PTR(-ENOENT);
+	spin_unlock(&sysctl_lock);
+	return head;
+}
+
+static void sysctl_head_finish(struct ctl_table_header *head)
+{
+	if (!head)
+		return;
+	spin_lock(&sysctl_lock);
+	unuse_table(head);
+	spin_unlock(&sysctl_lock);
+}
+
+static struct ctl_table_set *
+lookup_header_set(struct ctl_table_root *root)
+{
+	struct ctl_table_set *set = &root->default_set;
+	if (root->lookup)
+		set = root->lookup(root);
+	return set;
+}
+
+static struct ctl_table *lookup_entry(struct ctl_table_header **phead,
+				      struct ctl_dir *dir,
+				      const char *name, int namelen)
+{
+	struct ctl_table_header *head;
+	struct ctl_table *entry;
+
+	spin_lock(&sysctl_lock);
+	entry = find_entry(&head, dir, name, namelen);
+	if (entry && use_table(head))
+		*phead = head;
+	else
+		entry = NULL;
+	spin_unlock(&sysctl_lock);
+	return entry;
+}
+
+static struct ctl_node *first_usable_entry(struct rb_node *node)
+{
+	struct ctl_node *ctl_node;
+
+	for (;node; node = rb_next(node)) {
+		ctl_node = rb_entry(node, struct ctl_node, node);
+		if (use_table(ctl_node->header))
+			return ctl_node;
+	}
+	return NULL;
+}
+
+static void first_entry(struct ctl_dir *dir,
+	struct ctl_table_header **phead, struct ctl_table **pentry)
+{
+	struct ctl_table_header *head = NULL;
+	struct ctl_table *entry = NULL;
+	struct ctl_node *ctl_node;
+
+	spin_lock(&sysctl_lock);
+	ctl_node = first_usable_entry(rb_first(&dir->root));
+	spin_unlock(&sysctl_lock);
+	if (ctl_node) {
+		head = ctl_node->header;
+		entry = &head->ctl_table[ctl_node - head->node];
+	}
+	*phead = head;
+	*pentry = entry;
+}
+
+static void next_entry(struct ctl_table_header **phead, struct ctl_table **pentry)
+{
+	struct ctl_table_header *head = *phead;
+	struct ctl_table *entry = *pentry;
+	struct ctl_node *ctl_node = &head->node[entry - head->ctl_table];
+
+	spin_lock(&sysctl_lock);
+	unuse_table(head);
+
+	ctl_node = first_usable_entry(rb_next(&ctl_node->node));
+	spin_unlock(&sysctl_lock);
+	head = NULL;
+	if (ctl_node) {
+		head = ctl_node->header;
+		entry = &head->ctl_table[ctl_node - head->node];
+	}
+	*phead = head;
+	*pentry = entry;
+}
+
+/*
+ * sysctl_perm does NOT grant the superuser all rights automatically, because
+ * some sysctl variables are readonly even to root.
+ */
+
+static int test_perm(int mode, int op)
+{
+	if (uid_eq(current_euid(), GLOBAL_ROOT_UID))
+		mode >>= 6;
+	else if (in_egroup_p(GLOBAL_ROOT_GID))
+		mode >>= 3;
+	if ((op & ~mode & (MAY_READ|MAY_WRITE|MAY_EXEC)) == 0)
+		return 0;
+	return -EACCES;
+}
+
+static int sysctl_perm(struct ctl_table_header *head, struct ctl_table *table, int op)
+{
+	struct ctl_table_root *root = head->root;
+	int mode;
+
+	if (root->permissions)
+		mode = root->permissions(head, table);
+	else
+		mode = table->mode;
+
+	return test_perm(mode, op);
+}
+
+static struct inode *proc_sys_make_inode(struct super_block *sb,
+		struct ctl_table_header *head, struct ctl_table *table)
+{
+	struct ctl_table_root *root = head->root;
+	struct inode *inode;
+	struct proc_inode *ei;
+
+	inode = new_inode(sb);
+	if (!inode)
+		return ERR_PTR(-ENOMEM);
+
+	inode->i_ino = get_next_ino();
+
+	ei = PROC_I(inode);
+
+	spin_lock(&sysctl_lock);
+	if (unlikely(head->unregistering)) {
+		spin_unlock(&sysctl_lock);
+		iput(inode);
+		return ERR_PTR(-ENOENT);
+	}
+	ei->sysctl = head;
+	ei->sysctl_entry = table;
+	hlist_add_head_rcu(&ei->sibling_inodes, &head->inodes);
+	head->count++;
+	spin_unlock(&sysctl_lock);
+
+	inode->i_mtime = inode->i_atime = inode->i_ctime = current_time(inode);
+	inode->i_mode = table->mode;
+	if (!S_ISDIR(table->mode)) {
+		inode->i_mode |= S_IFREG;
+		inode->i_op = &proc_sys_inode_operations;
+		inode->i_fop = &proc_sys_file_operations;
+	} else {
+		inode->i_mode |= S_IFDIR;
+		inode->i_op = &proc_sys_dir_operations;
+		inode->i_fop = &proc_sys_dir_file_operations;
+		if (is_empty_dir(head))
+			make_empty_dir_inode(inode);
+	}
+
+	if (root->set_ownership)
+		root->set_ownership(head, table, &inode->i_uid, &inode->i_gid);
+	else {
+		inode->i_uid = GLOBAL_ROOT_UID;
+		inode->i_gid = GLOBAL_ROOT_GID;
+	}
+
+	return inode;
+}
+
+void proc_sys_evict_inode(struct inode *inode, struct ctl_table_header *head)
+{
+	spin_lock(&sysctl_lock);
+	hlist_del_init_rcu(&PROC_I(inode)->sibling_inodes);
+	if (!--head->count)
+		kfree_rcu(head, rcu);
+	spin_unlock(&sysctl_lock);
+}
+
+static struct ctl_table_header *grab_header(struct inode *inode)
+{
+	struct ctl_table_header *head = PROC_I(inode)->sysctl;
+	if (!head)
+		head = &sysctl_table_root.default_set.dir.header;
+	return sysctl_head_grab(head);
+}
+
+static struct dentry *proc_sys_lookup(struct inode *dir, struct dentry *dentry,
+					unsigned int flags)
+{
+	struct ctl_table_header *head = grab_header(dir);
+	struct ctl_table_header *h = NULL;
+	const struct qstr *name = &dentry->d_name;
+	struct ctl_table *p;
+	struct inode *inode;
+	struct dentry *err = ERR_PTR(-ENOENT);
+	struct ctl_dir *ctl_dir;
+	int ret;
+
+	if (IS_ERR(head))
+		return ERR_CAST(head);
+
+	ctl_dir = container_of(head, struct ctl_dir, header);
+
+	p = lookup_entry(&h, ctl_dir, name->name, name->len);
+	if (!p)
+		goto out;
+
+	if (S_ISLNK(p->mode)) {
+		ret = sysctl_follow_link(&h, &p);
+		err = ERR_PTR(ret);
+		if (ret)
+			goto out;
+	}
+
+	inode = proc_sys_make_inode(dir->i_sb, h ? h : head, p);
+	if (IS_ERR(inode)) {
+		err = ERR_CAST(inode);
+		goto out;
+	}
+
+	d_set_d_op(dentry, &proc_sys_dentry_operations);
+	err = d_splice_alias(inode, dentry);
+
+out:
+	if (h)
+		sysctl_head_finish(h);
+	sysctl_head_finish(head);
+	return err;
+}
+
+static ssize_t proc_sys_call_handler(struct kiocb *iocb, struct iov_iter *iter,
+		int write)
+{
+	struct inode *inode = file_inode(iocb->ki_filp);
+	struct ctl_table_header *head = grab_header(inode);
+	struct ctl_table *table = PROC_I(inode)->sysctl_entry;
+	size_t count = iov_iter_count(iter);
+	char *kbuf;
+	ssize_t error;
+
+	if (IS_ERR(head))
+		return PTR_ERR(head);
+
+	/*
+	 * At this point we know that the sysctl was not unregistered
+	 * and won't be until we finish.
+	 */
+	error = -EPERM;
+	if (sysctl_perm(head, table, write ? MAY_WRITE : MAY_READ))
+		goto out;
+
+	/* if that can happen at all, it should be -EINVAL, not -EISDIR */
+	error = -EINVAL;
+	if (!table->proc_handler)
+		goto out;
+
+	/* don't even try if the size is too large */
+	error = -ENOMEM;
+	if (count >= KMALLOC_MAX_SIZE)
+		goto out;
+	kbuf = kvzalloc(count + 1, GFP_KERNEL);
+	if (!kbuf)
+		goto out;
+
+	if (write) {
+		error = -EFAULT;
+		if (!copy_from_iter_full(kbuf, count, iter))
+			goto out_free_buf;
+		kbuf[count] = '\0';
+	}
+
+	error = BPF_CGROUP_RUN_PROG_SYSCTL(head, table, write, &kbuf, &count,
+					   &iocb->ki_pos);
+	if (error)
+		goto out_free_buf;
+
+	/* careful: calling conventions are nasty here */
+	error = table->proc_handler(table, write, kbuf, &count, &iocb->ki_pos);
+	if (error)
+		goto out_free_buf;
+
+	if (!write) {
+		error = -EFAULT;
+		if (copy_to_iter(kbuf, count, iter) < count)
+			goto out_free_buf;
+	}
+
+	error = count;
+out_free_buf:
+	kvfree(kbuf);
+out:
+	sysctl_head_finish(head);
+
+	return error;
+}
+
+static ssize_t proc_sys_read(struct kiocb *iocb, struct iov_iter *iter)
+{
+	return proc_sys_call_handler(iocb, iter, 0);
+}
+
+static ssize_t proc_sys_write(struct kiocb *iocb, struct iov_iter *iter)
+{
+	return proc_sys_call_handler(iocb, iter, 1);
+}
+
+static int proc_sys_open(struct inode *inode, struct file *filp)
+{
+	struct ctl_table_header *head = grab_header(inode);
+	struct ctl_table *table = PROC_I(inode)->sysctl_entry;
+
+	/* sysctl was unregistered */
+	if (IS_ERR(head))
+		return PTR_ERR(head);
+
+	if (table->poll)
+		filp->private_data = proc_sys_poll_event(table->poll);
+
+	sysctl_head_finish(head);
+
+	return 0;
+}
+
+static __poll_t proc_sys_poll(struct file *filp, poll_table *wait)
+{
+	struct inode *inode = file_inode(filp);
+	struct ctl_table_header *head = grab_header(inode);
+	struct ctl_table *table = PROC_I(inode)->sysctl_entry;
+	__poll_t ret = DEFAULT_POLLMASK;
+	unsigned long event;
+
+	/* sysctl was unregistered */
+	if (IS_ERR(head))
+		return EPOLLERR | EPOLLHUP;
+
+	if (!table->proc_handler)
+		goto out;
+
+	if (!table->poll)
+		goto out;
+
+	event = (unsigned long)filp->private_data;
+	poll_wait(filp, &table->poll->wait, wait);
+
+	if (event != atomic_read(&table->poll->event)) {
+		filp->private_data = proc_sys_poll_event(table->poll);
+		ret = EPOLLIN | EPOLLRDNORM | EPOLLERR | EPOLLPRI;
+	}
+
+out:
+	sysctl_head_finish(head);
+
+	return ret;
+}
+
+static bool proc_sys_fill_cache(struct file *file,
+				struct dir_context *ctx,
+				struct ctl_table_header *head,
+				struct ctl_table *table)
+{
+	struct dentry *child, *dir = file->f_path.dentry;
+	struct inode *inode;
+	struct qstr qname;
+	ino_t ino = 0;
+	unsigned type = DT_UNKNOWN;
+
+	qname.name = table->procname;
+	qname.len  = strlen(table->procname);
+	qname.hash = full_name_hash(dir, qname.name, qname.len);
+
+	child = d_lookup(dir, &qname);
+	if (!child) {
+		DECLARE_WAIT_QUEUE_HEAD_ONSTACK(wq);
+		child = d_alloc_parallel(dir, &qname, &wq);
+		if (IS_ERR(child))
+			return false;
+		if (d_in_lookup(child)) {
+			struct dentry *res;
+			inode = proc_sys_make_inode(dir->d_sb, head, table);
+			if (IS_ERR(inode)) {
+				d_lookup_done(child);
+				dput(child);
+				return false;
+			}
+			d_set_d_op(child, &proc_sys_dentry_operations);
+			res = d_splice_alias(inode, child);
+			d_lookup_done(child);
+			if (unlikely(res)) {
+				if (IS_ERR(res)) {
+					dput(child);
+					return false;
+				}
+				dput(child);
+				child = res;
+			}
+		}
+	}
+	inode = d_inode(child);
+	ino  = inode->i_ino;
+	type = inode->i_mode >> 12;
+	dput(child);
+	return dir_emit(ctx, qname.name, qname.len, ino, type);
+}
+
+static bool proc_sys_link_fill_cache(struct file *file,
+				    struct dir_context *ctx,
+				    struct ctl_table_header *head,
+				    struct ctl_table *table)
+{
+	bool ret = true;
+
+	head = sysctl_head_grab(head);
+	if (IS_ERR(head))
+		return false;
+
+	/* It is not an error if we can not follow the link ignore it */
+	if (sysctl_follow_link(&head, &table))
+		goto out;
+
+	ret = proc_sys_fill_cache(file, ctx, head, table);
+out:
+	sysctl_head_finish(head);
+	return ret;
+}
+
+static int scan(struct ctl_table_header *head, struct ctl_table *table,
+		unsigned long *pos, struct file *file,
+		struct dir_context *ctx)
+{
+	bool res;
+
+	if ((*pos)++ < ctx->pos)
+		return true;
+
+	if (unlikely(S_ISLNK(table->mode)))
+		res = proc_sys_link_fill_cache(file, ctx, head, table);
+	else
+		res = proc_sys_fill_cache(file, ctx, head, table);
+
+	if (res)
+		ctx->pos = *pos;
+
+	return res;
+}
+
+static int proc_sys_readdir(struct file *file, struct dir_context *ctx)
+{
+	struct ctl_table_header *head = grab_header(file_inode(file));
+	struct ctl_table_header *h = NULL;
+	struct ctl_table *entry;
+	struct ctl_dir *ctl_dir;
+	unsigned long pos;
+
+	if (IS_ERR(head))
+		return PTR_ERR(head);
+
+	ctl_dir = container_of(head, struct ctl_dir, header);
+
+	if (!dir_emit_dots(file, ctx))
+		goto out;
+
+	pos = 2;
+
+	for (first_entry(ctl_dir, &h, &entry); h; next_entry(&h, &entry)) {
+		if (!scan(h, entry, &pos, file, ctx)) {
+			sysctl_head_finish(h);
+			break;
+		}
+	}
+out:
+	sysctl_head_finish(head);
+	return 0;
+}
+
+static int proc_sys_permission(struct user_namespace *mnt_userns,
+			       struct inode *inode, int mask)
+{
+	/*
+	 * sysctl entries that are not writeable,
+	 * are _NOT_ writeable, capabilities or not.
+	 */
+	struct ctl_table_header *head;
+	struct ctl_table *table;
+	int error;
+
+	/* Executable files are not allowed under /proc/sys/ */
+	if ((mask & MAY_EXEC) && S_ISREG(inode->i_mode))
+		return -EACCES;
+
+	head = grab_header(inode);
+	if (IS_ERR(head))
+		return PTR_ERR(head);
+
+	table = PROC_I(inode)->sysctl_entry;
+	if (!table) /* global root - r-xr-xr-x */
+		error = mask & MAY_WRITE ? -EACCES : 0;
+	else /* Use the permissions on the sysctl table entry */
+		error = sysctl_perm(head, table, mask & ~MAY_NOT_BLOCK);
+
+	sysctl_head_finish(head);
+	return error;
+}
+
+static int proc_sys_setattr(struct user_namespace *mnt_userns,
+			    struct dentry *dentry, struct iattr *attr)
+{
+	struct inode *inode = d_inode(dentry);
+	int error;
+
+	if (attr->ia_valid & (ATTR_MODE | ATTR_UID | ATTR_GID))
+		return -EPERM;
+
+	error = setattr_prepare(&init_user_ns, dentry, attr);
+	if (error)
+		return error;
+
+	setattr_copy(&init_user_ns, inode, attr);
+	mark_inode_dirty(inode);
+	return 0;
+}
+
+static int proc_sys_getattr(struct user_namespace *mnt_userns,
+			    const struct path *path, struct kstat *stat,
+			    u32 request_mask, unsigned int query_flags)
+{
+	struct inode *inode = d_inode(path->dentry);
+	struct ctl_table_header *head = grab_header(inode);
+	struct ctl_table *table = PROC_I(inode)->sysctl_entry;
+
+	if (IS_ERR(head))
+		return PTR_ERR(head);
+
+	generic_fillattr(&init_user_ns, inode, stat);
+	if (table)
+		stat->mode = (stat->mode & S_IFMT) | table->mode;
+
+	sysctl_head_finish(head);
+	return 0;
+}
+
+static const struct file_operations proc_sys_file_operations = {
+	.open		= proc_sys_open,
+	.poll		= proc_sys_poll,
+	.read_iter	= proc_sys_read,
+	.write_iter	= proc_sys_write,
+	.splice_read	= generic_file_splice_read,
+	.splice_write	= iter_file_splice_write,
+	.llseek		= default_llseek,
+};
+
+static const struct file_operations proc_sys_dir_file_operations = {
+	.read		= generic_read_dir,
+	.iterate_shared	= proc_sys_readdir,
+	.llseek		= generic_file_llseek,
+};
+
+static const struct inode_operations proc_sys_inode_operations = {
+	.permission	= proc_sys_permission,
+	.setattr	= proc_sys_setattr,
+	.getattr	= proc_sys_getattr,
+};
+
+static const struct inode_operations proc_sys_dir_operations = {
+	.lookup		= proc_sys_lookup,
+	.permission	= proc_sys_permission,
+	.setattr	= proc_sys_setattr,
+	.getattr	= proc_sys_getattr,
+};
+
+static int proc_sys_revalidate(struct dentry *dentry, unsigned int flags)
+{
+	if (flags & LOOKUP_RCU)
+		return -ECHILD;
+	return !PROC_I(d_inode(dentry))->sysctl->unregistering;
+}
+
+static int proc_sys_delete(const struct dentry *dentry)
+{
+	return !!PROC_I(d_inode(dentry))->sysctl->unregistering;
+}
+
+static int sysctl_is_seen(struct ctl_table_header *p)
+{
+	struct ctl_table_set *set = p->set;
+	int res;
+	spin_lock(&sysctl_lock);
+	if (p->unregistering)
+		res = 0;
+	else if (!set->is_seen)
+		res = 1;
+	else
+		res = set->is_seen(set);
+	spin_unlock(&sysctl_lock);
+	return res;
+}
+
+static int proc_sys_compare(const struct dentry *dentry,
+		unsigned int len, const char *str, const struct qstr *name)
+{
+	struct ctl_table_header *head;
+	struct inode *inode;
+
+	/* Although proc doesn't have negative dentries, rcu-walk means
+	 * that inode here can be NULL */
+	/* AV: can it, indeed? */
+	inode = d_inode_rcu(dentry);
+	if (!inode)
+		return 1;
+	if (name->len != len)
+		return 1;
+	if (memcmp(name->name, str, len))
+		return 1;
+	head = rcu_dereference(PROC_I(inode)->sysctl);
+	return !head || !sysctl_is_seen(head);
+}
+
+static const struct dentry_operations proc_sys_dentry_operations = {
+	.d_revalidate	= proc_sys_revalidate,
+	.d_delete	= proc_sys_delete,
+	.d_compare	= proc_sys_compare,
+};
+
+static struct ctl_dir *find_subdir(struct ctl_dir *dir,
+				   const char *name, int namelen)
+{
+	struct ctl_table_header *head;
+	struct ctl_table *entry;
+
+	entry = find_entry(&head, dir, name, namelen);
+	if (!entry)
+		return ERR_PTR(-ENOENT);
+	if (!S_ISDIR(entry->mode))
+		return ERR_PTR(-ENOTDIR);
+	return container_of(head, struct ctl_dir, header);
+}
+
+static struct ctl_dir *new_dir(struct ctl_table_set *set,
+			       const char *name, int namelen)
+{
+	struct ctl_table *table;
+	struct ctl_dir *new;
+	struct ctl_node *node;
+	char *new_name;
+
+	new = kzalloc(sizeof(*new) + sizeof(struct ctl_node) +
+		      sizeof(struct ctl_table)*2 +  namelen + 1,
+		      GFP_KERNEL);
+	if (!new)
+		return NULL;
+
+	node = (struct ctl_node *)(new + 1);
+	table = (struct ctl_table *)(node + 1);
+	new_name = (char *)(table + 2);
+	memcpy(new_name, name, namelen);
+	table[0].procname = new_name;
+	table[0].mode = S_IFDIR|S_IRUGO|S_IXUGO;
+	init_header(&new->header, set->dir.header.root, set, node, table);
+
+	return new;
+}
+
+/**
+ * get_subdir - find or create a subdir with the specified name.
+ * @dir:  Directory to create the subdirectory in
+ * @name: The name of the subdirectory to find or create
+ * @namelen: The length of name
+ *
+ * Takes a directory with an elevated reference count so we know that
+ * if we drop the lock the directory will not go away.  Upon success
+ * the reference is moved from @dir to the returned subdirectory.
+ * Upon error an error code is returned and the reference on @dir is
+ * simply dropped.
+ */
+static struct ctl_dir *get_subdir(struct ctl_dir *dir,
+				  const char *name, int namelen)
+{
+	struct ctl_table_set *set = dir->header.set;
+	struct ctl_dir *subdir, *new = NULL;
+	int err;
+
+	spin_lock(&sysctl_lock);
+	subdir = find_subdir(dir, name, namelen);
+	if (!IS_ERR(subdir))
+		goto found;
+	if (PTR_ERR(subdir) != -ENOENT)
+		goto failed;
+
+	spin_unlock(&sysctl_lock);
+	new = new_dir(set, name, namelen);
+	spin_lock(&sysctl_lock);
+	subdir = ERR_PTR(-ENOMEM);
+	if (!new)
+		goto failed;
+
+	/* Was the subdir added while we dropped the lock? */
+	subdir = find_subdir(dir, name, namelen);
+	if (!IS_ERR(subdir))
+		goto found;
+	if (PTR_ERR(subdir) != -ENOENT)
+		goto failed;
+
+	/* Nope.  Use the our freshly made directory entry. */
+	err = insert_header(dir, &new->header);
+	subdir = ERR_PTR(err);
+	if (err)
+		goto failed;
+	subdir = new;
+found:
+	subdir->header.nreg++;
+failed:
+	if (IS_ERR(subdir)) {
+		pr_err("sysctl could not get directory: ");
+		sysctl_print_dir(dir);
+		pr_cont("%*.*s %ld\n", namelen, namelen, name,
+			PTR_ERR(subdir));
+	}
+	drop_sysctl_table(&dir->header);
+	if (new)
+		drop_sysctl_table(&new->header);
+	spin_unlock(&sysctl_lock);
+	return subdir;
+}
+
+static struct ctl_dir *xlate_dir(struct ctl_table_set *set, struct ctl_dir *dir)
+{
+	struct ctl_dir *parent;
+	const char *procname;
+	if (!dir->header.parent)
+		return &set->dir;
+	parent = xlate_dir(set, dir->header.parent);
+	if (IS_ERR(parent))
+		return parent;
+	procname = dir->header.ctl_table[0].procname;
+	return find_subdir(parent, procname, strlen(procname));
+}
+
+static int sysctl_follow_link(struct ctl_table_header **phead,
+	struct ctl_table **pentry)
+{
+	struct ctl_table_header *head;
+	struct ctl_table_root *root;
+	struct ctl_table_set *set;
+	struct ctl_table *entry;
+	struct ctl_dir *dir;
+	int ret;
+
+	spin_lock(&sysctl_lock);
+	root = (*pentry)->data;
+	set = lookup_header_set(root);
+	dir = xlate_dir(set, (*phead)->parent);
+	if (IS_ERR(dir))
+		ret = PTR_ERR(dir);
+	else {
+		const char *procname = (*pentry)->procname;
+		head = NULL;
+		entry = find_entry(&head, dir, procname, strlen(procname));
+		ret = -ENOENT;
+		if (entry && use_table(head)) {
+			unuse_table(*phead);
+			*phead = head;
+			*pentry = entry;
+			ret = 0;
+		}
+	}
+
+	spin_unlock(&sysctl_lock);
+	return ret;
+}
+
+static int sysctl_err(const char *path, struct ctl_table *table, char *fmt, ...)
+{
+	struct va_format vaf;
+	va_list args;
+
+	va_start(args, fmt);
+	vaf.fmt = fmt;
+	vaf.va = &args;
+
+	pr_err("sysctl table check failed: %s/%s %pV\n",
+	       path, table->procname, &vaf);
+
+	va_end(args);
+	return -EINVAL;
+}
+
+static int sysctl_check_table_array(const char *path, struct ctl_table *table)
+{
+	int err = 0;
+
+	if ((table->proc_handler == proc_douintvec) ||
+	    (table->proc_handler == proc_douintvec_minmax)) {
+		if (table->maxlen != sizeof(unsigned int))
+			err |= sysctl_err(path, table, "array not allowed");
+	}
+
+	if (table->proc_handler == proc_dou8vec_minmax) {
+		if (table->maxlen != sizeof(u8))
+			err |= sysctl_err(path, table, "array not allowed");
+	}
+
+	return err;
+}
+
+static int sysctl_check_table(const char *path, struct ctl_table *table)
+{
+	struct ctl_table *entry;
+	int err = 0;
+	list_for_each_table_entry(entry, table) {
+		if (entry->child)
+			err |= sysctl_err(path, entry, "Not a file");
+
+		if ((entry->proc_handler == proc_dostring) ||
+		    (entry->proc_handler == proc_dointvec) ||
+		    (entry->proc_handler == proc_douintvec) ||
+		    (entry->proc_handler == proc_douintvec_minmax) ||
+		    (entry->proc_handler == proc_dointvec_minmax) ||
+		    (entry->proc_handler == proc_dou8vec_minmax) ||
+		    (entry->proc_handler == proc_dointvec_jiffies) ||
+		    (entry->proc_handler == proc_dointvec_userhz_jiffies) ||
+		    (entry->proc_handler == proc_dointvec_ms_jiffies) ||
+		    (entry->proc_handler == proc_doulongvec_minmax) ||
+		    (entry->proc_handler == proc_doulongvec_ms_jiffies_minmax)) {
+			if (!entry->data)
+				err |= sysctl_err(path, entry, "No data");
+			if (!entry->maxlen)
+				err |= sysctl_err(path, entry, "No maxlen");
+			else
+				err |= sysctl_check_table_array(path, entry);
+		}
+		if (!entry->proc_handler)
+			err |= sysctl_err(path, entry, "No proc_handler");
+
+		if ((entry->mode & (S_IRUGO|S_IWUGO)) != entry->mode)
+			err |= sysctl_err(path, entry, "bogus .mode 0%o",
+				entry->mode);
+	}
+	return err;
+}
+
+static struct ctl_table_header *new_links(struct ctl_dir *dir, struct ctl_table *table,
+	struct ctl_table_root *link_root)
+{
+	struct ctl_table *link_table, *entry, *link;
+	struct ctl_table_header *links;
+	struct ctl_node *node;
+	char *link_name;
+	int nr_entries, name_bytes;
+
+	name_bytes = 0;
+	nr_entries = 0;
+	list_for_each_table_entry(entry, table) {
+		nr_entries++;
+		name_bytes += strlen(entry->procname) + 1;
+	}
+
+	links = kzalloc(sizeof(struct ctl_table_header) +
+			sizeof(struct ctl_node)*nr_entries +
+			sizeof(struct ctl_table)*(nr_entries + 1) +
+			name_bytes,
+			GFP_KERNEL);
+
+	if (!links)
+		return NULL;
+
+	node = (struct ctl_node *)(links + 1);
+	link_table = (struct ctl_table *)(node + nr_entries);
+	link_name = (char *)&link_table[nr_entries + 1];
+	link = link_table;
+
+	list_for_each_table_entry(entry, table) {
+		int len = strlen(entry->procname) + 1;
+		memcpy(link_name, entry->procname, len);
+		link->procname = link_name;
+		link->mode = S_IFLNK|S_IRWXUGO;
+		link->data = link_root;
+		link_name += len;
+		link++;
+	}
+	init_header(links, dir->header.root, dir->header.set, node, link_table);
+	links->nreg = nr_entries;
+
+	return links;
+}
+
+static bool get_links(struct ctl_dir *dir,
+	struct ctl_table *table, struct ctl_table_root *link_root)
+{
+	struct ctl_table_header *head;
+	struct ctl_table *entry, *link;
+
+	/* Are there links available for every entry in table? */
+	list_for_each_table_entry(entry, table) {
+		const char *procname = entry->procname;
+		link = find_entry(&head, dir, procname, strlen(procname));
+		if (!link)
+			return false;
+		if (S_ISDIR(link->mode) && S_ISDIR(entry->mode))
+			continue;
+		if (S_ISLNK(link->mode) && (link->data == link_root))
+			continue;
+		return false;
+	}
+
+	/* The checks passed.  Increase the registration count on the links */
+	list_for_each_table_entry(entry, table) {
+		const char *procname = entry->procname;
+		link = find_entry(&head, dir, procname, strlen(procname));
+		head->nreg++;
+	}
+	return true;
+}
+
+static int insert_links(struct ctl_table_header *head)
+{
+	struct ctl_table_set *root_set = &sysctl_table_root.default_set;
+	struct ctl_dir *core_parent;
+	struct ctl_table_header *links;
+	int err;
+
+	if (head->set == root_set)
+		return 0;
+
+	core_parent = xlate_dir(root_set, head->parent);
+	if (IS_ERR(core_parent))
+		return 0;
+
+	if (get_links(core_parent, head->ctl_table, head->root))
+		return 0;
+
+	core_parent->header.nreg++;
+	spin_unlock(&sysctl_lock);
+
+	links = new_links(core_parent, head->ctl_table, head->root);
+
+	spin_lock(&sysctl_lock);
+	err = -ENOMEM;
+	if (!links)
+		goto out;
+
+	err = 0;
+	if (get_links(core_parent, head->ctl_table, head->root)) {
+		kfree(links);
+		goto out;
+	}
+
+	err = insert_header(core_parent, links);
+	if (err)
+		kfree(links);
+out:
+	drop_sysctl_table(&core_parent->header);
+	return err;
+}
+
+/**
+ * __register_sysctl_table - register a leaf sysctl table
+ * @set: Sysctl tree to register on
+ * @path: The path to the directory the sysctl table is in.
+ * @table: the top-level table structure without any child. This table
+ * 	 should not be free'd after registration. So it should not be
+ * 	 used on stack. It can either be a global or dynamically allocated
+ * 	 by the caller and free'd later after sysctl unregistration.
+ *
+ * Register a sysctl table hierarchy. @table should be a filled in ctl_table
+ * array. A completely 0 filled entry terminates the table.
+ *
+ * The members of the &struct ctl_table structure are used as follows:
+ *
+ * procname - the name of the sysctl file under /proc/sys. Set to %NULL to not
+ *            enter a sysctl file
+ *
+ * data - a pointer to data for use by proc_handler
+ *
+ * maxlen - the maximum size in bytes of the data
+ *
+ * mode - the file permissions for the /proc/sys file
+ *
+ * child - must be %NULL.
+ *
+ * proc_handler - the text handler routine (described below)
+ *
+ * extra1, extra2 - extra pointers usable by the proc handler routines
+ * XXX: we should eventually modify these to use long min / max [0]
+ * [0] https://lkml.kernel.org/87zgpte9o4.fsf@email.froward.int.ebiederm.org
+ *
+ * Leaf nodes in the sysctl tree will be represented by a single file
+ * under /proc; non-leaf nodes (where child is not NULL) are not allowed,
+ * sysctl_check_table() verifies this.
+ *
+ * There must be a proc_handler routine for any terminal nodes.
+ * Several default handlers are available to cover common cases -
+ *
+ * proc_dostring(), proc_dointvec(), proc_dointvec_jiffies(),
+ * proc_dointvec_userhz_jiffies(), proc_dointvec_minmax(),
+ * proc_doulongvec_ms_jiffies_minmax(), proc_doulongvec_minmax()
+ *
+ * It is the handler's job to read the input buffer from user memory
+ * and process it. The handler should return 0 on success.
+ *
+ * This routine returns %NULL on a failure to register, and a pointer
+ * to the table header on success.
+ */
+struct ctl_table_header *__register_sysctl_table(
+	struct ctl_table_set *set,
+	const char *path, struct ctl_table *table)
+{
+	struct ctl_table_root *root = set->dir.header.root;
+	struct ctl_table_header *header;
+	const char *name, *nextname;
+	struct ctl_dir *dir;
+	struct ctl_table *entry;
+	struct ctl_node *node;
+	int nr_entries = 0;
+
+	list_for_each_table_entry(entry, table)
+		nr_entries++;
+
+	header = kzalloc(sizeof(struct ctl_table_header) +
+			 sizeof(struct ctl_node)*nr_entries, GFP_KERNEL_ACCOUNT);
+	if (!header)
+		return NULL;
+
+	node = (struct ctl_node *)(header + 1);
+	init_header(header, root, set, node, table);
+	if (sysctl_check_table(path, table))
+		goto fail;
+
+	spin_lock(&sysctl_lock);
+	dir = &set->dir;
+	/* Reference moved down the directory tree get_subdir */
+	dir->header.nreg++;
+	spin_unlock(&sysctl_lock);
+
+	/* Find the directory for the ctl_table */
+	for (name = path; name; name = nextname) {
+		int namelen;
+		nextname = strchr(name, '/');
+		if (nextname) {
+			namelen = nextname - name;
+			nextname++;
+		} else {
+			namelen = strlen(name);
+		}
+		if (namelen == 0)
+			continue;
+
+		/*
+		 * namelen ensures if name is "foo/bar/yay" only foo is
+		 * registered first. We traverse as if using mkdir -p and
+		 * return a ctl_dir for the last directory entry.
+		 */
+		dir = get_subdir(dir, name, namelen);
+		if (IS_ERR(dir))
+			goto fail;
+	}
+
+	spin_lock(&sysctl_lock);
+	if (insert_header(dir, header))
+		goto fail_put_dir_locked;
+
+	drop_sysctl_table(&dir->header);
+	spin_unlock(&sysctl_lock);
+
+	return header;
+
+fail_put_dir_locked:
+	drop_sysctl_table(&dir->header);
+	spin_unlock(&sysctl_lock);
+fail:
+	kfree(header);
+	dump_stack();
+	return NULL;
+}
+
+/**
+ * register_sysctl - register a sysctl table
+ * @path: The path to the directory the sysctl table is in. If the path
+ * 	doesn't exist we will create it for you.
+ * @table: the table structure. The calller must ensure the life of the @table
+ * 	will be kept during the lifetime use of the syctl. It must not be freed
+ * 	until unregister_sysctl_table() is called with the given returned table
+ * 	with this registration. If your code is non modular then you don't need
+ * 	to call unregister_sysctl_table() and can instead use something like
+ * 	register_sysctl_init() which does not care for the result of the syctl
+ * 	registration.
+ *
+ * Register a sysctl table. @table should be a filled in ctl_table
+ * array. A completely 0 filled entry terminates the table.
+ *
+ * See __register_sysctl_table for more details.
+ */
+struct ctl_table_header *register_sysctl(const char *path, struct ctl_table *table)
+{
+	return __register_sysctl_table(&sysctl_table_root.default_set,
+					path, table);
+}
+EXPORT_SYMBOL(register_sysctl);
+
+/**
+ * __register_sysctl_init() - register sysctl table to path
+ * @path: path name for sysctl base. If that path doesn't exist we will create
+ * 	it for you.
+ * @table: This is the sysctl table that needs to be registered to the path.
+ * 	The caller must ensure the life of the @table will be kept during the
+ * 	lifetime use of the sysctl.
+ * @table_name: The name of sysctl table, only used for log printing when
+ *              registration fails
+ *
+ * The sysctl interface is used by userspace to query or modify at runtime
+ * a predefined value set on a variable. These variables however have default
+ * values pre-set. Code which depends on these variables will always work even
+ * if register_sysctl() fails. If register_sysctl() fails you'd just loose the
+ * ability to query or modify the sysctls dynamically at run time. Chances of
+ * register_sysctl() failing on init are extremely low, and so for both reasons
+ * this function does not return any error as it is used by initialization code.
+ *
+ * Context: if your base directory does not exist it will be created for you.
+ */
+void __init __register_sysctl_init(const char *path, struct ctl_table *table,
+				 const char *table_name)
+{
+	struct ctl_table_header *hdr = register_sysctl(path, table);
+
+	if (unlikely(!hdr)) {
+		pr_err("failed when register_sysctl %s to %s\n", table_name, path);
+		return;
+	}
+	kmemleak_not_leak(hdr);
+}
+
+static char *append_path(const char *path, char *pos, const char *name)
+{
+	int namelen;
+	namelen = strlen(name);
+	if (((pos - path) + namelen + 2) >= PATH_MAX)
+		return NULL;
+	memcpy(pos, name, namelen);
+	pos[namelen] = '/';
+	pos[namelen + 1] = '\0';
+	pos += namelen + 1;
+	return pos;
+}
+
+static int count_subheaders(struct ctl_table *table)
+{
+	int has_files = 0;
+	int nr_subheaders = 0;
+	struct ctl_table *entry;
+
+	/* special case: no directory and empty directory */
+	if (!table || !table->procname)
+		return 1;
+
+	list_for_each_table_entry(entry, table) {
+		if (entry->child)
+			nr_subheaders += count_subheaders(entry->child);
+		else
+			has_files = 1;
+	}
+	return nr_subheaders + has_files;
+}
+
+static int register_leaf_sysctl_tables(const char *path, char *pos,
+	struct ctl_table_header ***subheader, struct ctl_table_set *set,
+	struct ctl_table *table)
+{
+	struct ctl_table *ctl_table_arg = NULL;
+	struct ctl_table *entry, *files;
+	int nr_files = 0;
+	int nr_dirs = 0;
+	int err = -ENOMEM;
+
+	list_for_each_table_entry(entry, table) {
+		if (entry->child)
+			nr_dirs++;
+		else
+			nr_files++;
+	}
+
+	files = table;
+	/* If there are mixed files and directories we need a new table */
+	if (nr_dirs && nr_files) {
+		struct ctl_table *new;
+		files = kcalloc(nr_files + 1, sizeof(struct ctl_table),
+				GFP_KERNEL);
+		if (!files)
+			goto out;
+
+		ctl_table_arg = files;
+		new = files;
+
+		list_for_each_table_entry(entry, table) {
+			if (entry->child)
+				continue;
+			*new = *entry;
+			new++;
+		}
+	}
+
+	/* Register everything except a directory full of subdirectories */
+	if (nr_files || !nr_dirs) {
+		struct ctl_table_header *header;
+		header = __register_sysctl_table(set, path, files);
+		if (!header) {
+			kfree(ctl_table_arg);
+			goto out;
+		}
+
+		/* Remember if we need to free the file table */
+		header->ctl_table_arg = ctl_table_arg;
+		**subheader = header;
+		(*subheader)++;
+	}
+
+	/* Recurse into the subdirectories. */
+	list_for_each_table_entry(entry, table) {
+		char *child_pos;
+
+		if (!entry->child)
+			continue;
+
+		err = -ENAMETOOLONG;
+		child_pos = append_path(path, pos, entry->procname);
+		if (!child_pos)
+			goto out;
+
+		err = register_leaf_sysctl_tables(path, child_pos, subheader,
+						  set, entry->child);
+		pos[0] = '\0';
+		if (err)
+			goto out;
+	}
+	err = 0;
+out:
+	/* On failure our caller will unregister all registered subheaders */
+	return err;
+}
+
+/**
+ * __register_sysctl_paths - register a sysctl table hierarchy
+ * @set: Sysctl tree to register on
+ * @path: The path to the directory the sysctl table is in.
+ * @table: the top-level table structure
+ *
+ * Register a sysctl table hierarchy. @table should be a filled in ctl_table
+ * array. A completely 0 filled entry terminates the table.
+ * We are slowly deprecating this call so avoid its use.
+ *
+ * See __register_sysctl_table for more details.
+ */
+struct ctl_table_header *__register_sysctl_paths(
+	struct ctl_table_set *set,
+	const struct ctl_path *path, struct ctl_table *table)
+{
+	struct ctl_table *ctl_table_arg = table;
+	int nr_subheaders = count_subheaders(table);
+	struct ctl_table_header *header = NULL, **subheaders, **subheader;
+	const struct ctl_path *component;
+	char *new_path, *pos;
+
+	pos = new_path = kmalloc(PATH_MAX, GFP_KERNEL);
+	if (!new_path)
+		return NULL;
+
+	pos[0] = '\0';
+	for (component = path; component->procname; component++) {
+		pos = append_path(new_path, pos, component->procname);
+		if (!pos)
+			goto out;
+	}
+	while (table->procname && table->child && !table[1].procname) {
+		pos = append_path(new_path, pos, table->procname);
+		if (!pos)
+			goto out;
+		table = table->child;
+	}
+	if (nr_subheaders == 1) {
+		header = __register_sysctl_table(set, new_path, table);
+		if (header)
+			header->ctl_table_arg = ctl_table_arg;
+	} else {
+		header = kzalloc(sizeof(*header) +
+				 sizeof(*subheaders)*nr_subheaders, GFP_KERNEL);
+		if (!header)
+			goto out;
+
+		subheaders = (struct ctl_table_header **) (header + 1);
+		subheader = subheaders;
+		header->ctl_table_arg = ctl_table_arg;
+
+		if (register_leaf_sysctl_tables(new_path, pos, &subheader,
+						set, table))
+			goto err_register_leaves;
+	}
+
+out:
+	kfree(new_path);
+	return header;
+
+err_register_leaves:
+	while (subheader > subheaders) {
+		struct ctl_table_header *subh = *(--subheader);
+		struct ctl_table *table = subh->ctl_table_arg;
+		unregister_sysctl_table(subh);
+		kfree(table);
+	}
+	kfree(header);
+	header = NULL;
+	goto out;
+}
+
+/**
+ * register_sysctl_paths - register a sysctl table hierarchy
+ * @path: The path to the directory the sysctl table is in.
+ * @table: the top-level table structure
+ *
+ * Register a sysctl table hierarchy. @table should be a filled in ctl_table
+ * array. A completely 0 filled entry terminates the table.
+ * We are slowly deprecating this caller so avoid future uses of it.
+ *
+ * See __register_sysctl_paths for more details.
+ */
+struct ctl_table_header *register_sysctl_paths(const struct ctl_path *path,
+						struct ctl_table *table)
+{
+	return __register_sysctl_paths(&sysctl_table_root.default_set,
+					path, table);
+}
+EXPORT_SYMBOL(register_sysctl_paths);
+
+/**
+ * register_sysctl_table - register a sysctl table hierarchy
+ * @table: the top-level table structure
+ *
+ * Register a sysctl table hierarchy. @table should be a filled in ctl_table
+ * array. A completely 0 filled entry terminates the table.
+ *
+ * See register_sysctl_paths for more details.
+ */
+struct ctl_table_header *register_sysctl_table(struct ctl_table *table)
+{
+	static const struct ctl_path null_path[] = { {} };
+
+	return register_sysctl_paths(null_path, table);
+}
+EXPORT_SYMBOL(register_sysctl_table);
+
+int __register_sysctl_base(struct ctl_table *base_table)
+{
+	struct ctl_table_header *hdr;
+
+	hdr = register_sysctl_table(base_table);
+	kmemleak_not_leak(hdr);
+	return 0;
+}
+
+static void put_links(struct ctl_table_header *header)
+{
+	struct ctl_table_set *root_set = &sysctl_table_root.default_set;
+	struct ctl_table_root *root = header->root;
+	struct ctl_dir *parent = header->parent;
+	struct ctl_dir *core_parent;
+	struct ctl_table *entry;
+
+	if (header->set == root_set)
+		return;
+
+	core_parent = xlate_dir(root_set, parent);
+	if (IS_ERR(core_parent))
+		return;
+
+	list_for_each_table_entry(entry, header->ctl_table) {
+		struct ctl_table_header *link_head;
+		struct ctl_table *link;
+		const char *name = entry->procname;
+
+		link = find_entry(&link_head, core_parent, name, strlen(name));
+		if (link &&
+		    ((S_ISDIR(link->mode) && S_ISDIR(entry->mode)) ||
+		     (S_ISLNK(link->mode) && (link->data == root)))) {
+			drop_sysctl_table(link_head);
+		}
+		else {
+			pr_err("sysctl link missing during unregister: ");
+			sysctl_print_dir(parent);
+			pr_cont("%s\n", name);
+		}
+	}
+}
+
+static void drop_sysctl_table(struct ctl_table_header *header)
+{
+	struct ctl_dir *parent = header->parent;
+
+	if (--header->nreg)
+		return;
+
+	if (parent) {
+		put_links(header);
+		start_unregistering(header);
+	}
+
+	if (!--header->count)
+		kfree_rcu(header, rcu);
+
+	if (parent)
+		drop_sysctl_table(&parent->header);
+}
+
+/**
+ * unregister_sysctl_table - unregister a sysctl table hierarchy
+ * @header: the header returned from register_sysctl_table
+ *
+ * Unregisters the sysctl table and all children. proc entries may not
+ * actually be removed until they are no longer used by anyone.
+ */
+void unregister_sysctl_table(struct ctl_table_header * header)
+{
+	int nr_subheaders;
+	might_sleep();
+
+	if (header == NULL)
+		return;
+
+	nr_subheaders = count_subheaders(header->ctl_table_arg);
+	if (unlikely(nr_subheaders > 1)) {
+		struct ctl_table_header **subheaders;
+		int i;
+
+		subheaders = (struct ctl_table_header **)(header + 1);
+		for (i = nr_subheaders -1; i >= 0; i--) {
+			struct ctl_table_header *subh = subheaders[i];
+			struct ctl_table *table = subh->ctl_table_arg;
+			unregister_sysctl_table(subh);
+			kfree(table);
+		}
+		kfree(header);
+		return;
+	}
+
+	spin_lock(&sysctl_lock);
+	drop_sysctl_table(header);
+	spin_unlock(&sysctl_lock);
+}
+EXPORT_SYMBOL(unregister_sysctl_table);
+
+void setup_sysctl_set(struct ctl_table_set *set,
+	struct ctl_table_root *root,
+	int (*is_seen)(struct ctl_table_set *))
+{
+	memset(set, 0, sizeof(*set));
+	set->is_seen = is_seen;
+	init_header(&set->dir.header, root, set, NULL, root_table);
+}
+
+void retire_sysctl_set(struct ctl_table_set *set)
+{
+	WARN_ON(!RB_EMPTY_ROOT(&set->dir.root));
+}
+
+int __init proc_sys_init(void)
+{
+	struct proc_dir_entry *proc_sys_root;
+
+	proc_sys_root = proc_mkdir("sys", NULL);
+	proc_sys_root->proc_iops = &proc_sys_dir_operations;
+	proc_sys_root->proc_dir_ops = &proc_sys_dir_file_operations;
+	proc_sys_root->nlink = 0;
+
+	return sysctl_init_bases();
+}
+
+struct sysctl_alias {
+	const char *kernel_param;
+	const char *sysctl_param;
+};
+
+/*
+ * Historically some settings had both sysctl and a command line parameter.
+ * With the generic sysctl. parameter support, we can handle them at a single
+ * place and only keep the historical name for compatibility. This is not meant
+ * to add brand new aliases. When adding existing aliases, consider whether
+ * the possibly different moment of changing the value (e.g. from early_param
+ * to the moment do_sysctl_args() is called) is an issue for the specific
+ * parameter.
+ */
+static const struct sysctl_alias sysctl_aliases[] = {
+	{"hardlockup_all_cpu_backtrace",	"kernel.hardlockup_all_cpu_backtrace" },
+	{"hung_task_panic",			"kernel.hung_task_panic" },
+	{"numa_zonelist_order",			"vm.numa_zonelist_order" },
+	{"softlockup_all_cpu_backtrace",	"kernel.softlockup_all_cpu_backtrace" },
+	{ }
+};
+
+static const char *sysctl_find_alias(char *param)
+{
+	const struct sysctl_alias *alias;
+
+	for (alias = &sysctl_aliases[0]; alias->kernel_param != NULL; alias++) {
+		if (strcmp(alias->kernel_param, param) == 0)
+			return alias->sysctl_param;
+	}
+
+	return NULL;
+}
+
+bool sysctl_is_alias(char *param)
+{
+	const char *alias = sysctl_find_alias(param);
+
+	return alias != NULL;
+}
+
+/* Set sysctl value passed on kernel command line. */
+static int process_sysctl_arg(char *param, char *val,
+			       const char *unused, void *arg)
+{
+	char *path;
+	struct vfsmount **proc_mnt = arg;
+	struct file_system_type *proc_fs_type;
+	struct file *file;
+	int len;
+	int err;
+	loff_t pos = 0;
+	ssize_t wret;
+
+	if (strncmp(param, "sysctl", sizeof("sysctl") - 1) == 0) {
+		param += sizeof("sysctl") - 1;
+
+		if (param[0] != '/' && param[0] != '.')
+			return 0;
+
+		param++;
+	} else {
+		param = (char *) sysctl_find_alias(param);
+		if (!param)
+			return 0;
+	}
+
+	if (!val)
+		return -EINVAL;
+	len = strlen(val);
+	if (len == 0)
+		return -EINVAL;
+
+	/*
+	 * To set sysctl options, we use a temporary mount of proc, look up the
+	 * respective sys/ file and write to it. To avoid mounting it when no
+	 * options were given, we mount it only when the first sysctl option is
+	 * found. Why not a persistent mount? There are problems with a
+	 * persistent mount of proc in that it forces userspace not to use any
+	 * proc mount options.
+	 */
+	if (!*proc_mnt) {
+		proc_fs_type = get_fs_type("proc");
+		if (!proc_fs_type) {
+			pr_err("Failed to find procfs to set sysctl from command line\n");
+			return 0;
+		}
+		*proc_mnt = kern_mount(proc_fs_type);
+		put_filesystem(proc_fs_type);
+		if (IS_ERR(*proc_mnt)) {
+			pr_err("Failed to mount procfs to set sysctl from command line\n");
+			return 0;
+		}
+	}
+
+	path = kasprintf(GFP_KERNEL, "sys/%s", param);
+	if (!path)
+		panic("%s: Failed to allocate path for %s\n", __func__, param);
+	strreplace(path, '.', '/');
+
+	file = file_open_root_mnt(*proc_mnt, path, O_WRONLY, 0);
+	if (IS_ERR(file)) {
+		err = PTR_ERR(file);
+		if (err == -ENOENT)
+			pr_err("Failed to set sysctl parameter '%s=%s': parameter not found\n",
+				param, val);
+		else if (err == -EACCES)
+			pr_err("Failed to set sysctl parameter '%s=%s': permission denied (read-only?)\n",
+				param, val);
+		else
+			pr_err("Error %pe opening proc file to set sysctl parameter '%s=%s'\n",
+				file, param, val);
+		goto out;
+	}
+	wret = kernel_write(file, val, len, &pos);
+	if (wret < 0) {
+		err = wret;
+		if (err == -EINVAL)
+			pr_err("Failed to set sysctl parameter '%s=%s': invalid value\n",
+				param, val);
+		else
+			pr_err("Error %pe writing to proc file to set sysctl parameter '%s=%s'\n",
+				ERR_PTR(err), param, val);
+	} else if (wret != len) {
+		pr_err("Wrote only %zd bytes of %d writing to proc file %s to set sysctl parameter '%s=%s\n",
+			wret, len, path, param, val);
+	}
+
+	err = filp_close(file, NULL);
+	if (err)
+		pr_err("Error %pe closing proc file to set sysctl parameter '%s=%s\n",
+			ERR_PTR(err), param, val);
+out:
+	kfree(path);
+	return 0;
+}
+
+void do_sysctl_args(void)
+{
+	char *command_line;
+	struct vfsmount *proc_mnt = NULL;
+
+	command_line = kstrdup(saved_command_line, GFP_KERNEL);
+	if (!command_line)
+		panic("%s: Failed to allocate copy of command line\n", __func__);
+
+	parse_args("Setting sysctl args", command_line,
+		   NULL, 0, -1, -1, &proc_mnt, process_sysctl_arg);
+
+	if (proc_mnt)
+		kern_unmount(proc_mnt);
+
+	kfree(command_line);
+}
diff --git a/fs/proc/proc_tty.c b/fs/proc/proc_tty.c
new file mode 100644
index 000000000..5c6a5ceab
--- /dev/null
+++ b/fs/proc/proc_tty.c
@@ -0,0 +1,177 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * proc_tty.c -- handles /proc/tty
+ *
+ * Copyright 1997, Theodore Ts'o
+ */
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/errno.h>
+#include <linux/time.h>
+#include <linux/proc_fs.h>
+#include <linux/stat.h>
+#include <linux/tty.h>
+#include <linux/seq_file.h>
+#include <linux/bitops.h>
+#include "internal.h"
+
+/*
+ * The /proc/tty directory inodes...
+ */
+static struct proc_dir_entry *proc_tty_driver;
+
+/*
+ * This is the handler for /proc/tty/drivers
+ */
+static void show_tty_range(struct seq_file *m, struct tty_driver *p,
+	dev_t from, int num)
+{
+	seq_printf(m, "%-20s ", p->driver_name ? p->driver_name : "unknown");
+	seq_printf(m, "/dev/%-8s ", p->name);
+	if (p->num > 1) {
+		seq_printf(m, "%3d %d-%d ", MAJOR(from), MINOR(from),
+			MINOR(from) + num - 1);
+	} else {
+		seq_printf(m, "%3d %7d ", MAJOR(from), MINOR(from));
+	}
+	switch (p->type) {
+	case TTY_DRIVER_TYPE_SYSTEM:
+		seq_puts(m, "system");
+		if (p->subtype == SYSTEM_TYPE_TTY)
+			seq_puts(m, ":/dev/tty");
+		else if (p->subtype == SYSTEM_TYPE_SYSCONS)
+			seq_puts(m, ":console");
+		else if (p->subtype == SYSTEM_TYPE_CONSOLE)
+			seq_puts(m, ":vtmaster");
+		break;
+	case TTY_DRIVER_TYPE_CONSOLE:
+		seq_puts(m, "console");
+		break;
+	case TTY_DRIVER_TYPE_SERIAL:
+		seq_puts(m, "serial");
+		break;
+	case TTY_DRIVER_TYPE_PTY:
+		if (p->subtype == PTY_TYPE_MASTER)
+			seq_puts(m, "pty:master");
+		else if (p->subtype == PTY_TYPE_SLAVE)
+			seq_puts(m, "pty:slave");
+		else
+			seq_puts(m, "pty");
+		break;
+	default:
+		seq_printf(m, "type:%d.%d", p->type, p->subtype);
+	}
+	seq_putc(m, '\n');
+}
+
+static int show_tty_driver(struct seq_file *m, void *v)
+{
+	struct tty_driver *p = list_entry(v, struct tty_driver, tty_drivers);
+	dev_t from = MKDEV(p->major, p->minor_start);
+	dev_t to = from + p->num;
+
+	if (&p->tty_drivers == tty_drivers.next) {
+		/* pseudo-drivers first */
+		seq_printf(m, "%-20s /dev/%-8s ", "/dev/tty", "tty");
+		seq_printf(m, "%3d %7d ", TTYAUX_MAJOR, 0);
+		seq_puts(m, "system:/dev/tty\n");
+		seq_printf(m, "%-20s /dev/%-8s ", "/dev/console", "console");
+		seq_printf(m, "%3d %7d ", TTYAUX_MAJOR, 1);
+		seq_puts(m, "system:console\n");
+#ifdef CONFIG_UNIX98_PTYS
+		seq_printf(m, "%-20s /dev/%-8s ", "/dev/ptmx", "ptmx");
+		seq_printf(m, "%3d %7d ", TTYAUX_MAJOR, 2);
+		seq_puts(m, "system\n");
+#endif
+#ifdef CONFIG_VT
+		seq_printf(m, "%-20s /dev/%-8s ", "/dev/vc/0", "vc/0");
+		seq_printf(m, "%3d %7d ", TTY_MAJOR, 0);
+		seq_puts(m, "system:vtmaster\n");
+#endif
+	}
+
+	while (MAJOR(from) < MAJOR(to)) {
+		dev_t next = MKDEV(MAJOR(from)+1, 0);
+		show_tty_range(m, p, from, next - from);
+		from = next;
+	}
+	if (from != to)
+		show_tty_range(m, p, from, to - from);
+	return 0;
+}
+
+/* iterator */
+static void *t_start(struct seq_file *m, loff_t *pos)
+{
+	mutex_lock(&tty_mutex);
+	return seq_list_start(&tty_drivers, *pos);
+}
+
+static void *t_next(struct seq_file *m, void *v, loff_t *pos)
+{
+	return seq_list_next(v, &tty_drivers, pos);
+}
+
+static void t_stop(struct seq_file *m, void *v)
+{
+	mutex_unlock(&tty_mutex);
+}
+
+static const struct seq_operations tty_drivers_op = {
+	.start	= t_start,
+	.next	= t_next,
+	.stop	= t_stop,
+	.show	= show_tty_driver
+};
+
+/*
+ * This function is called by tty_register_driver() to handle
+ * registering the driver's /proc handler into /proc/tty/driver/<foo>
+ */
+void proc_tty_register_driver(struct tty_driver *driver)
+{
+	struct proc_dir_entry *ent;
+		
+	if (!driver->driver_name || driver->proc_entry ||
+	    !driver->ops->proc_show)
+		return;
+
+	ent = proc_create_single_data(driver->driver_name, 0, proc_tty_driver,
+			       driver->ops->proc_show, driver);
+	driver->proc_entry = ent;
+}
+
+/*
+ * This function is called by tty_unregister_driver()
+ */
+void proc_tty_unregister_driver(struct tty_driver *driver)
+{
+	struct proc_dir_entry *ent;
+
+	ent = driver->proc_entry;
+	if (!ent)
+		return;
+		
+	remove_proc_entry(ent->name, proc_tty_driver);
+	
+	driver->proc_entry = NULL;
+}
+
+/*
+ * Called by proc_root_init() to initialize the /proc/tty subtree
+ */
+void __init proc_tty_init(void)
+{
+	if (!proc_mkdir("tty", NULL))
+		return;
+	proc_mkdir("tty/ldisc", NULL);	/* Preserved: it's userspace visible */
+	/*
+	 * /proc/tty/driver/serial reveals the exact character counts for
+	 * serial links which is just too easy to abuse for inferring
+	 * password lengths and inter-keystroke timings during password
+	 * entry.
+	 */
+	proc_tty_driver = proc_mkdir_mode("tty/driver", S_IRUSR|S_IXUSR, NULL);
+	proc_create_seq("tty/ldiscs", 0, NULL, &tty_ldiscs_seq_ops);
+	proc_create_seq("tty/drivers", 0, NULL, &tty_drivers_op);
+}
diff --git a/fs/proc/root.c b/fs/proc/root.c
new file mode 100644
index 000000000..3c2ee3eb1
--- /dev/null
+++ b/fs/proc/root.c
@@ -0,0 +1,375 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ *  linux/fs/proc/root.c
+ *
+ *  Copyright (C) 1991, 1992 Linus Torvalds
+ *
+ *  proc root directory handling functions
+ */
+#include <linux/errno.h>
+#include <linux/time.h>
+#include <linux/proc_fs.h>
+#include <linux/stat.h>
+#include <linux/init.h>
+#include <linux/sched.h>
+#include <linux/sched/stat.h>
+#include <linux/module.h>
+#include <linux/bitops.h>
+#include <linux/user_namespace.h>
+#include <linux/fs_context.h>
+#include <linux/mount.h>
+#include <linux/pid_namespace.h>
+#include <linux/fs_parser.h>
+#include <linux/cred.h>
+#include <linux/magic.h>
+#include <linux/slab.h>
+
+#include "internal.h"
+
+struct proc_fs_context {
+	struct pid_namespace	*pid_ns;
+	unsigned int		mask;
+	enum proc_hidepid	hidepid;
+	int			gid;
+	enum proc_pidonly	pidonly;
+};
+
+enum proc_param {
+	Opt_gid,
+	Opt_hidepid,
+	Opt_subset,
+};
+
+static const struct fs_parameter_spec proc_fs_parameters[] = {
+	fsparam_u32("gid",	Opt_gid),
+	fsparam_string("hidepid",	Opt_hidepid),
+	fsparam_string("subset",	Opt_subset),
+	{}
+};
+
+static inline int valid_hidepid(unsigned int value)
+{
+	return (value == HIDEPID_OFF ||
+		value == HIDEPID_NO_ACCESS ||
+		value == HIDEPID_INVISIBLE ||
+		value == HIDEPID_NOT_PTRACEABLE);
+}
+
+static int proc_parse_hidepid_param(struct fs_context *fc, struct fs_parameter *param)
+{
+	struct proc_fs_context *ctx = fc->fs_private;
+	struct fs_parameter_spec hidepid_u32_spec = fsparam_u32("hidepid", Opt_hidepid);
+	struct fs_parse_result result;
+	int base = (unsigned long)hidepid_u32_spec.data;
+
+	if (param->type != fs_value_is_string)
+		return invalf(fc, "proc: unexpected type of hidepid value\n");
+
+	if (!kstrtouint(param->string, base, &result.uint_32)) {
+		if (!valid_hidepid(result.uint_32))
+			return invalf(fc, "proc: unknown value of hidepid - %s\n", param->string);
+		ctx->hidepid = result.uint_32;
+		return 0;
+	}
+
+	if (!strcmp(param->string, "off"))
+		ctx->hidepid = HIDEPID_OFF;
+	else if (!strcmp(param->string, "noaccess"))
+		ctx->hidepid = HIDEPID_NO_ACCESS;
+	else if (!strcmp(param->string, "invisible"))
+		ctx->hidepid = HIDEPID_INVISIBLE;
+	else if (!strcmp(param->string, "ptraceable"))
+		ctx->hidepid = HIDEPID_NOT_PTRACEABLE;
+	else
+		return invalf(fc, "proc: unknown value of hidepid - %s\n", param->string);
+
+	return 0;
+}
+
+static int proc_parse_subset_param(struct fs_context *fc, char *value)
+{
+	struct proc_fs_context *ctx = fc->fs_private;
+
+	while (value) {
+		char *ptr = strchr(value, ',');
+
+		if (ptr != NULL)
+			*ptr++ = '\0';
+
+		if (*value != '\0') {
+			if (!strcmp(value, "pid")) {
+				ctx->pidonly = PROC_PIDONLY_ON;
+			} else {
+				return invalf(fc, "proc: unsupported subset option - %s\n", value);
+			}
+		}
+		value = ptr;
+	}
+
+	return 0;
+}
+
+static int proc_parse_param(struct fs_context *fc, struct fs_parameter *param)
+{
+	struct proc_fs_context *ctx = fc->fs_private;
+	struct fs_parse_result result;
+	int opt;
+
+	opt = fs_parse(fc, proc_fs_parameters, param, &result);
+	if (opt < 0)
+		return opt;
+
+	switch (opt) {
+	case Opt_gid:
+		ctx->gid = result.uint_32;
+		break;
+
+	case Opt_hidepid:
+		if (proc_parse_hidepid_param(fc, param))
+			return -EINVAL;
+		break;
+
+	case Opt_subset:
+		if (proc_parse_subset_param(fc, param->string) < 0)
+			return -EINVAL;
+		break;
+
+	default:
+		return -EINVAL;
+	}
+
+	ctx->mask |= 1 << opt;
+	return 0;
+}
+
+static void proc_apply_options(struct proc_fs_info *fs_info,
+			       struct fs_context *fc,
+			       struct user_namespace *user_ns)
+{
+	struct proc_fs_context *ctx = fc->fs_private;
+
+	if (ctx->mask & (1 << Opt_gid))
+		fs_info->pid_gid = make_kgid(user_ns, ctx->gid);
+	if (ctx->mask & (1 << Opt_hidepid))
+		fs_info->hide_pid = ctx->hidepid;
+	if (ctx->mask & (1 << Opt_subset))
+		fs_info->pidonly = ctx->pidonly;
+}
+
+static int proc_fill_super(struct super_block *s, struct fs_context *fc)
+{
+	struct proc_fs_context *ctx = fc->fs_private;
+	struct inode *root_inode;
+	struct proc_fs_info *fs_info;
+	int ret;
+
+	fs_info = kzalloc(sizeof(*fs_info), GFP_KERNEL);
+	if (!fs_info)
+		return -ENOMEM;
+
+	fs_info->pid_ns = get_pid_ns(ctx->pid_ns);
+	proc_apply_options(fs_info, fc, current_user_ns());
+
+	/* User space would break if executables or devices appear on proc */
+	s->s_iflags |= SB_I_USERNS_VISIBLE | SB_I_NOEXEC | SB_I_NODEV;
+	s->s_flags |= SB_NODIRATIME | SB_NOSUID | SB_NOEXEC;
+	s->s_blocksize = 1024;
+	s->s_blocksize_bits = 10;
+	s->s_magic = PROC_SUPER_MAGIC;
+	s->s_op = &proc_sops;
+	s->s_time_gran = 1;
+	s->s_fs_info = fs_info;
+
+	/*
+	 * procfs isn't actually a stacking filesystem; however, there is
+	 * too much magic going on inside it to permit stacking things on
+	 * top of it
+	 */
+	s->s_stack_depth = FILESYSTEM_MAX_STACK_DEPTH;
+
+	/* procfs dentries and inodes don't require IO to create */
+	s->s_shrink.seeks = 0;
+
+	pde_get(&proc_root);
+	root_inode = proc_get_inode(s, &proc_root);
+	if (!root_inode) {
+		pr_err("proc_fill_super: get root inode failed\n");
+		return -ENOMEM;
+	}
+
+	s->s_root = d_make_root(root_inode);
+	if (!s->s_root) {
+		pr_err("proc_fill_super: allocate dentry failed\n");
+		return -ENOMEM;
+	}
+
+	ret = proc_setup_self(s);
+	if (ret) {
+		return ret;
+	}
+	return proc_setup_thread_self(s);
+}
+
+static int proc_reconfigure(struct fs_context *fc)
+{
+	struct super_block *sb = fc->root->d_sb;
+	struct proc_fs_info *fs_info = proc_sb_info(sb);
+
+	sync_filesystem(sb);
+
+	proc_apply_options(fs_info, fc, current_user_ns());
+	return 0;
+}
+
+static int proc_get_tree(struct fs_context *fc)
+{
+	return get_tree_nodev(fc, proc_fill_super);
+}
+
+static void proc_fs_context_free(struct fs_context *fc)
+{
+	struct proc_fs_context *ctx = fc->fs_private;
+
+	put_pid_ns(ctx->pid_ns);
+	kfree(ctx);
+}
+
+static const struct fs_context_operations proc_fs_context_ops = {
+	.free		= proc_fs_context_free,
+	.parse_param	= proc_parse_param,
+	.get_tree	= proc_get_tree,
+	.reconfigure	= proc_reconfigure,
+};
+
+static int proc_init_fs_context(struct fs_context *fc)
+{
+	struct proc_fs_context *ctx;
+
+	ctx = kzalloc(sizeof(struct proc_fs_context), GFP_KERNEL);
+	if (!ctx)
+		return -ENOMEM;
+
+	ctx->pid_ns = get_pid_ns(task_active_pid_ns(current));
+	put_user_ns(fc->user_ns);
+	fc->user_ns = get_user_ns(ctx->pid_ns->user_ns);
+	fc->fs_private = ctx;
+	fc->ops = &proc_fs_context_ops;
+	return 0;
+}
+
+static void proc_kill_sb(struct super_block *sb)
+{
+	struct proc_fs_info *fs_info = proc_sb_info(sb);
+
+	if (!fs_info) {
+		kill_anon_super(sb);
+		return;
+	}
+
+	dput(fs_info->proc_self);
+	dput(fs_info->proc_thread_self);
+
+	kill_anon_super(sb);
+	put_pid_ns(fs_info->pid_ns);
+	kfree(fs_info);
+}
+
+static struct file_system_type proc_fs_type = {
+	.name			= "proc",
+	.init_fs_context	= proc_init_fs_context,
+	.parameters		= proc_fs_parameters,
+	.kill_sb		= proc_kill_sb,
+	.fs_flags		= FS_USERNS_MOUNT | FS_DISALLOW_NOTIFY_PERM,
+};
+
+void __init proc_root_init(void)
+{
+	proc_init_kmemcache();
+	set_proc_pid_nlink();
+	proc_self_init();
+	proc_thread_self_init();
+	proc_symlink("mounts", NULL, "self/mounts");
+
+	proc_net_init();
+	proc_mkdir("fs", NULL);
+	proc_mkdir("driver", NULL);
+	proc_create_mount_point("fs/nfsd"); /* somewhere for the nfsd filesystem to be mounted */
+#if defined(CONFIG_SUN_OPENPROMFS) || defined(CONFIG_SUN_OPENPROMFS_MODULE)
+	/* just give it a mountpoint */
+	proc_create_mount_point("openprom");
+#endif
+	proc_tty_init();
+	proc_mkdir("bus", NULL);
+	proc_sys_init();
+
+	/*
+	 * Last things last. It is not like userspace processes eager
+	 * to open /proc files exist at this point but register last
+	 * anyway.
+	 */
+	register_filesystem(&proc_fs_type);
+}
+
+static int proc_root_getattr(struct user_namespace *mnt_userns,
+			     const struct path *path, struct kstat *stat,
+			     u32 request_mask, unsigned int query_flags)
+{
+	generic_fillattr(&init_user_ns, d_inode(path->dentry), stat);
+	stat->nlink = proc_root.nlink + nr_processes();
+	return 0;
+}
+
+static struct dentry *proc_root_lookup(struct inode * dir, struct dentry * dentry, unsigned int flags)
+{
+	if (!proc_pid_lookup(dentry, flags))
+		return NULL;
+
+	return proc_lookup(dir, dentry, flags);
+}
+
+static int proc_root_readdir(struct file *file, struct dir_context *ctx)
+{
+	if (ctx->pos < FIRST_PROCESS_ENTRY) {
+		int error = proc_readdir(file, ctx);
+		if (unlikely(error <= 0))
+			return error;
+		ctx->pos = FIRST_PROCESS_ENTRY;
+	}
+
+	return proc_pid_readdir(file, ctx);
+}
+
+/*
+ * The root /proc directory is special, as it has the
+ * <pid> directories. Thus we don't use the generic
+ * directory handling functions for that..
+ */
+static const struct file_operations proc_root_operations = {
+	.read		 = generic_read_dir,
+	.iterate_shared	 = proc_root_readdir,
+	.llseek		= generic_file_llseek,
+};
+
+/*
+ * proc root can do almost nothing..
+ */
+static const struct inode_operations proc_root_inode_operations = {
+	.lookup		= proc_root_lookup,
+	.getattr	= proc_root_getattr,
+};
+
+/*
+ * This is the root "inode" in the /proc tree..
+ */
+struct proc_dir_entry proc_root = {
+	.low_ino	= PROC_ROOT_INO, 
+	.namelen	= 5, 
+	.mode		= S_IFDIR | S_IRUGO | S_IXUGO, 
+	.nlink		= 2, 
+	.refcnt		= REFCOUNT_INIT(1),
+	.proc_iops	= &proc_root_inode_operations, 
+	.proc_dir_ops	= &proc_root_operations,
+	.parent		= &proc_root,
+	.subdir		= RB_ROOT,
+	.name		= "/proc",
+};
diff --git a/fs/proc/self.c b/fs/proc/self.c
new file mode 100644
index 000000000..72cd69bca
--- /dev/null
+++ b/fs/proc/self.c
@@ -0,0 +1,73 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/cache.h>
+#include <linux/sched.h>
+#include <linux/slab.h>
+#include <linux/pid_namespace.h>
+#include "internal.h"
+
+/*
+ * /proc/self:
+ */
+static const char *proc_self_get_link(struct dentry *dentry,
+				      struct inode *inode,
+				      struct delayed_call *done)
+{
+	struct pid_namespace *ns = proc_pid_ns(inode->i_sb);
+	pid_t tgid = task_tgid_nr_ns(current, ns);
+	char *name;
+
+	if (!tgid)
+		return ERR_PTR(-ENOENT);
+	/* max length of unsigned int in decimal + NULL term */
+	name = kmalloc(10 + 1, dentry ? GFP_KERNEL : GFP_ATOMIC);
+	if (unlikely(!name))
+		return dentry ? ERR_PTR(-ENOMEM) : ERR_PTR(-ECHILD);
+	sprintf(name, "%u", tgid);
+	set_delayed_call(done, kfree_link, name);
+	return name;
+}
+
+static const struct inode_operations proc_self_inode_operations = {
+	.get_link	= proc_self_get_link,
+};
+
+static unsigned self_inum __ro_after_init;
+
+int proc_setup_self(struct super_block *s)
+{
+	struct inode *root_inode = d_inode(s->s_root);
+	struct proc_fs_info *fs_info = proc_sb_info(s);
+	struct dentry *self;
+	int ret = -ENOMEM;
+
+	inode_lock(root_inode);
+	self = d_alloc_name(s->s_root, "self");
+	if (self) {
+		struct inode *inode = new_inode(s);
+		if (inode) {
+			inode->i_ino = self_inum;
+			inode->i_mtime = inode->i_atime = inode->i_ctime = current_time(inode);
+			inode->i_mode = S_IFLNK | S_IRWXUGO;
+			inode->i_uid = GLOBAL_ROOT_UID;
+			inode->i_gid = GLOBAL_ROOT_GID;
+			inode->i_op = &proc_self_inode_operations;
+			d_add(self, inode);
+			ret = 0;
+		} else {
+			dput(self);
+		}
+	}
+	inode_unlock(root_inode);
+
+	if (ret)
+		pr_err("proc_fill_super: can't allocate /proc/self\n");
+	else
+		fs_info->proc_self = self;
+
+	return ret;
+}
+
+void __init proc_self_init(void)
+{
+	proc_alloc_inum(&self_inum);
+}
diff --git a/fs/proc/softirqs.c b/fs/proc/softirqs.c
new file mode 100644
index 000000000..f4616083f
--- /dev/null
+++ b/fs/proc/softirqs.c
@@ -0,0 +1,37 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/init.h>
+#include <linux/kernel_stat.h>
+#include <linux/proc_fs.h>
+#include <linux/seq_file.h>
+#include "internal.h"
+
+/*
+ * /proc/softirqs  ... display the number of softirqs
+ */
+static int show_softirqs(struct seq_file *p, void *v)
+{
+	int i, j;
+
+	seq_puts(p, "                    ");
+	for_each_possible_cpu(i)
+		seq_printf(p, "CPU%-8d", i);
+	seq_putc(p, '\n');
+
+	for (i = 0; i < NR_SOFTIRQS; i++) {
+		seq_printf(p, "%12s:", softirq_to_name[i]);
+		for_each_possible_cpu(j)
+			seq_printf(p, " %10u", kstat_softirqs_cpu(i, j));
+		seq_putc(p, '\n');
+	}
+	return 0;
+}
+
+static int __init proc_softirqs_init(void)
+{
+	struct proc_dir_entry *pde;
+
+	pde = proc_create_single("softirqs", 0, NULL, show_softirqs);
+	pde_make_permanent(pde);
+	return 0;
+}
+fs_initcall(proc_softirqs_init);
diff --git a/fs/proc/stat.c b/fs/proc/stat.c
new file mode 100644
index 000000000..4fb8729a6
--- /dev/null
+++ b/fs/proc/stat.c
@@ -0,0 +1,242 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/cpumask.h>
+#include <linux/fs.h>
+#include <linux/init.h>
+#include <linux/interrupt.h>
+#include <linux/kernel_stat.h>
+#include <linux/proc_fs.h>
+#include <linux/sched.h>
+#include <linux/sched/stat.h>
+#include <linux/seq_file.h>
+#include <linux/slab.h>
+#include <linux/time.h>
+#include <linux/time_namespace.h>
+#include <linux/irqnr.h>
+#include <linux/sched/cputime.h>
+#include <linux/tick.h>
+
+#ifndef arch_irq_stat_cpu
+#define arch_irq_stat_cpu(cpu) 0
+#endif
+#ifndef arch_irq_stat
+#define arch_irq_stat() 0
+#endif
+
+#ifdef arch_idle_time
+
+u64 get_idle_time(struct kernel_cpustat *kcs, int cpu)
+{
+	u64 idle;
+
+	idle = kcs->cpustat[CPUTIME_IDLE];
+	if (cpu_online(cpu) && !nr_iowait_cpu(cpu))
+		idle += arch_idle_time(cpu);
+	return idle;
+}
+
+static u64 get_iowait_time(struct kernel_cpustat *kcs, int cpu)
+{
+	u64 iowait;
+
+	iowait = kcs->cpustat[CPUTIME_IOWAIT];
+	if (cpu_online(cpu) && nr_iowait_cpu(cpu))
+		iowait += arch_idle_time(cpu);
+	return iowait;
+}
+
+#else
+
+u64 get_idle_time(struct kernel_cpustat *kcs, int cpu)
+{
+	u64 idle, idle_usecs = -1ULL;
+
+	if (cpu_online(cpu))
+		idle_usecs = get_cpu_idle_time_us(cpu, NULL);
+
+	if (idle_usecs == -1ULL)
+		/* !NO_HZ or cpu offline so we can rely on cpustat.idle */
+		idle = kcs->cpustat[CPUTIME_IDLE];
+	else
+		idle = idle_usecs * NSEC_PER_USEC;
+
+	return idle;
+}
+
+static u64 get_iowait_time(struct kernel_cpustat *kcs, int cpu)
+{
+	u64 iowait, iowait_usecs = -1ULL;
+
+	if (cpu_online(cpu))
+		iowait_usecs = get_cpu_iowait_time_us(cpu, NULL);
+
+	if (iowait_usecs == -1ULL)
+		/* !NO_HZ or cpu offline so we can rely on cpustat.iowait */
+		iowait = kcs->cpustat[CPUTIME_IOWAIT];
+	else
+		iowait = iowait_usecs * NSEC_PER_USEC;
+
+	return iowait;
+}
+
+#endif
+
+static void show_irq_gap(struct seq_file *p, unsigned int gap)
+{
+	static const char zeros[] = " 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0";
+
+	while (gap > 0) {
+		unsigned int inc;
+
+		inc = min_t(unsigned int, gap, ARRAY_SIZE(zeros) / 2);
+		seq_write(p, zeros, 2 * inc);
+		gap -= inc;
+	}
+}
+
+static void show_all_irqs(struct seq_file *p)
+{
+	unsigned int i, next = 0;
+
+	for_each_active_irq(i) {
+		show_irq_gap(p, i - next);
+		seq_put_decimal_ull(p, " ", kstat_irqs_usr(i));
+		next = i + 1;
+	}
+	show_irq_gap(p, nr_irqs - next);
+}
+
+static int show_stat(struct seq_file *p, void *v)
+{
+	int i, j;
+	u64 user, nice, system, idle, iowait, irq, softirq, steal;
+	u64 guest, guest_nice;
+	u64 sum = 0;
+	u64 sum_softirq = 0;
+	unsigned int per_softirq_sums[NR_SOFTIRQS] = {0};
+	struct timespec64 boottime;
+
+	user = nice = system = idle = iowait =
+		irq = softirq = steal = 0;
+	guest = guest_nice = 0;
+	getboottime64(&boottime);
+	/* shift boot timestamp according to the timens offset */
+	timens_sub_boottime(&boottime);
+
+	for_each_possible_cpu(i) {
+		struct kernel_cpustat kcpustat;
+		u64 *cpustat = kcpustat.cpustat;
+
+		kcpustat_cpu_fetch(&kcpustat, i);
+
+		user		+= cpustat[CPUTIME_USER];
+		nice		+= cpustat[CPUTIME_NICE];
+		system		+= cpustat[CPUTIME_SYSTEM];
+		idle		+= get_idle_time(&kcpustat, i);
+		iowait		+= get_iowait_time(&kcpustat, i);
+		irq		+= cpustat[CPUTIME_IRQ];
+		softirq		+= cpustat[CPUTIME_SOFTIRQ];
+		steal		+= cpustat[CPUTIME_STEAL];
+		guest		+= cpustat[CPUTIME_GUEST];
+		guest_nice	+= cpustat[CPUTIME_GUEST_NICE];
+		sum		+= kstat_cpu_irqs_sum(i);
+		sum		+= arch_irq_stat_cpu(i);
+
+		for (j = 0; j < NR_SOFTIRQS; j++) {
+			unsigned int softirq_stat = kstat_softirqs_cpu(j, i);
+
+			per_softirq_sums[j] += softirq_stat;
+			sum_softirq += softirq_stat;
+		}
+	}
+	sum += arch_irq_stat();
+
+	seq_put_decimal_ull(p, "cpu  ", nsec_to_clock_t(user));
+	seq_put_decimal_ull(p, " ", nsec_to_clock_t(nice));
+	seq_put_decimal_ull(p, " ", nsec_to_clock_t(system));
+	seq_put_decimal_ull(p, " ", nsec_to_clock_t(idle));
+	seq_put_decimal_ull(p, " ", nsec_to_clock_t(iowait));
+	seq_put_decimal_ull(p, " ", nsec_to_clock_t(irq));
+	seq_put_decimal_ull(p, " ", nsec_to_clock_t(softirq));
+	seq_put_decimal_ull(p, " ", nsec_to_clock_t(steal));
+	seq_put_decimal_ull(p, " ", nsec_to_clock_t(guest));
+	seq_put_decimal_ull(p, " ", nsec_to_clock_t(guest_nice));
+	seq_putc(p, '\n');
+
+	for_each_online_cpu(i) {
+		struct kernel_cpustat kcpustat;
+		u64 *cpustat = kcpustat.cpustat;
+
+		kcpustat_cpu_fetch(&kcpustat, i);
+
+		/* Copy values here to work around gcc-2.95.3, gcc-2.96 */
+		user		= cpustat[CPUTIME_USER];
+		nice		= cpustat[CPUTIME_NICE];
+		system		= cpustat[CPUTIME_SYSTEM];
+		idle		= get_idle_time(&kcpustat, i);
+		iowait		= get_iowait_time(&kcpustat, i);
+		irq		= cpustat[CPUTIME_IRQ];
+		softirq		= cpustat[CPUTIME_SOFTIRQ];
+		steal		= cpustat[CPUTIME_STEAL];
+		guest		= cpustat[CPUTIME_GUEST];
+		guest_nice	= cpustat[CPUTIME_GUEST_NICE];
+		seq_printf(p, "cpu%d", i);
+		seq_put_decimal_ull(p, " ", nsec_to_clock_t(user));
+		seq_put_decimal_ull(p, " ", nsec_to_clock_t(nice));
+		seq_put_decimal_ull(p, " ", nsec_to_clock_t(system));
+		seq_put_decimal_ull(p, " ", nsec_to_clock_t(idle));
+		seq_put_decimal_ull(p, " ", nsec_to_clock_t(iowait));
+		seq_put_decimal_ull(p, " ", nsec_to_clock_t(irq));
+		seq_put_decimal_ull(p, " ", nsec_to_clock_t(softirq));
+		seq_put_decimal_ull(p, " ", nsec_to_clock_t(steal));
+		seq_put_decimal_ull(p, " ", nsec_to_clock_t(guest));
+		seq_put_decimal_ull(p, " ", nsec_to_clock_t(guest_nice));
+		seq_putc(p, '\n');
+	}
+	seq_put_decimal_ull(p, "intr ", (unsigned long long)sum);
+
+	show_all_irqs(p);
+
+	seq_printf(p,
+		"\nctxt %llu\n"
+		"btime %llu\n"
+		"processes %lu\n"
+		"procs_running %u\n"
+		"procs_blocked %u\n",
+		nr_context_switches(),
+		(unsigned long long)boottime.tv_sec,
+		total_forks,
+		nr_running(),
+		nr_iowait());
+
+	seq_put_decimal_ull(p, "softirq ", (unsigned long long)sum_softirq);
+
+	for (i = 0; i < NR_SOFTIRQS; i++)
+		seq_put_decimal_ull(p, " ", per_softirq_sums[i]);
+	seq_putc(p, '\n');
+
+	return 0;
+}
+
+static int stat_open(struct inode *inode, struct file *file)
+{
+	unsigned int size = 1024 + 128 * num_online_cpus();
+
+	/* minimum size to display an interrupt count : 2 bytes */
+	size += 2 * nr_irqs;
+	return single_open_size(file, show_stat, NULL, size);
+}
+
+static const struct proc_ops stat_proc_ops = {
+	.proc_flags	= PROC_ENTRY_PERMANENT,
+	.proc_open	= stat_open,
+	.proc_read_iter	= seq_read_iter,
+	.proc_lseek	= seq_lseek,
+	.proc_release	= single_release,
+};
+
+static int __init proc_stat_init(void)
+{
+	proc_create("stat", 0, NULL, &stat_proc_ops);
+	return 0;
+}
+fs_initcall(proc_stat_init);
diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
new file mode 100644
index 000000000..a954305fb
--- /dev/null
+++ b/fs/proc/task_mmu.c
@@ -0,0 +1,2026 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/pagewalk.h>
+#include <linux/mm_inline.h>
+#include <linux/hugetlb.h>
+#include <linux/huge_mm.h>
+#include <linux/mount.h>
+#include <linux/seq_file.h>
+#include <linux/highmem.h>
+#include <linux/ptrace.h>
+#include <linux/slab.h>
+#include <linux/pagemap.h>
+#include <linux/mempolicy.h>
+#include <linux/rmap.h>
+#include <linux/swap.h>
+#include <linux/sched/mm.h>
+#include <linux/swapops.h>
+#include <linux/mmu_notifier.h>
+#include <linux/page_idle.h>
+#include <linux/shmem_fs.h>
+#include <linux/uaccess.h>
+#include <linux/pkeys.h>
+
+#include <asm/elf.h>
+#include <asm/tlb.h>
+#include <asm/tlbflush.h>
+#include "internal.h"
+
+#define SEQ_PUT_DEC(str, val) \
+		seq_put_decimal_ull_width(m, str, (val) << (PAGE_SHIFT-10), 8)
+void task_mem(struct seq_file *m, struct mm_struct *mm)
+{
+	unsigned long text, lib, swap, anon, file, shmem;
+	unsigned long hiwater_vm, total_vm, hiwater_rss, total_rss;
+
+	anon = get_mm_counter(mm, MM_ANONPAGES);
+	file = get_mm_counter(mm, MM_FILEPAGES);
+	shmem = get_mm_counter(mm, MM_SHMEMPAGES);
+
+	/*
+	 * Note: to minimize their overhead, mm maintains hiwater_vm and
+	 * hiwater_rss only when about to *lower* total_vm or rss.  Any
+	 * collector of these hiwater stats must therefore get total_vm
+	 * and rss too, which will usually be the higher.  Barriers? not
+	 * worth the effort, such snapshots can always be inconsistent.
+	 */
+	hiwater_vm = total_vm = mm->total_vm;
+	if (hiwater_vm < mm->hiwater_vm)
+		hiwater_vm = mm->hiwater_vm;
+	hiwater_rss = total_rss = anon + file + shmem;
+	if (hiwater_rss < mm->hiwater_rss)
+		hiwater_rss = mm->hiwater_rss;
+
+	/* split executable areas between text and lib */
+	text = PAGE_ALIGN(mm->end_code) - (mm->start_code & PAGE_MASK);
+	text = min(text, mm->exec_vm << PAGE_SHIFT);
+	lib = (mm->exec_vm << PAGE_SHIFT) - text;
+
+	swap = get_mm_counter(mm, MM_SWAPENTS);
+	SEQ_PUT_DEC("VmPeak:\t", hiwater_vm);
+	SEQ_PUT_DEC(" kB\nVmSize:\t", total_vm);
+	SEQ_PUT_DEC(" kB\nVmLck:\t", mm->locked_vm);
+	SEQ_PUT_DEC(" kB\nVmPin:\t", atomic64_read(&mm->pinned_vm));
+	SEQ_PUT_DEC(" kB\nVmHWM:\t", hiwater_rss);
+	SEQ_PUT_DEC(" kB\nVmRSS:\t", total_rss);
+	SEQ_PUT_DEC(" kB\nRssAnon:\t", anon);
+	SEQ_PUT_DEC(" kB\nRssFile:\t", file);
+	SEQ_PUT_DEC(" kB\nRssShmem:\t", shmem);
+	SEQ_PUT_DEC(" kB\nVmData:\t", mm->data_vm);
+	SEQ_PUT_DEC(" kB\nVmStk:\t", mm->stack_vm);
+	seq_put_decimal_ull_width(m,
+		    " kB\nVmExe:\t", text >> 10, 8);
+	seq_put_decimal_ull_width(m,
+		    " kB\nVmLib:\t", lib >> 10, 8);
+	seq_put_decimal_ull_width(m,
+		    " kB\nVmPTE:\t", mm_pgtables_bytes(mm) >> 10, 8);
+	SEQ_PUT_DEC(" kB\nVmSwap:\t", swap);
+	seq_puts(m, " kB\n");
+	hugetlb_report_usage(m, mm);
+}
+#undef SEQ_PUT_DEC
+
+unsigned long task_vsize(struct mm_struct *mm)
+{
+	return PAGE_SIZE * mm->total_vm;
+}
+
+unsigned long task_statm(struct mm_struct *mm,
+			 unsigned long *shared, unsigned long *text,
+			 unsigned long *data, unsigned long *resident)
+{
+	*shared = get_mm_counter(mm, MM_FILEPAGES) +
+			get_mm_counter(mm, MM_SHMEMPAGES);
+	*text = (PAGE_ALIGN(mm->end_code) - (mm->start_code & PAGE_MASK))
+								>> PAGE_SHIFT;
+	*data = mm->data_vm + mm->stack_vm;
+	*resident = *shared + get_mm_counter(mm, MM_ANONPAGES);
+	return mm->total_vm;
+}
+
+#ifdef CONFIG_NUMA
+/*
+ * Save get_task_policy() for show_numa_map().
+ */
+static void hold_task_mempolicy(struct proc_maps_private *priv)
+{
+	struct task_struct *task = priv->task;
+
+	task_lock(task);
+	priv->task_mempolicy = get_task_policy(task);
+	mpol_get(priv->task_mempolicy);
+	task_unlock(task);
+}
+static void release_task_mempolicy(struct proc_maps_private *priv)
+{
+	mpol_put(priv->task_mempolicy);
+}
+#else
+static void hold_task_mempolicy(struct proc_maps_private *priv)
+{
+}
+static void release_task_mempolicy(struct proc_maps_private *priv)
+{
+}
+#endif
+
+static struct vm_area_struct *proc_get_vma(struct proc_maps_private *priv,
+						loff_t *ppos)
+{
+	struct vm_area_struct *vma = vma_next(&priv->iter);
+
+	if (vma) {
+		*ppos = vma->vm_start;
+	} else {
+		*ppos = -2UL;
+		vma = get_gate_vma(priv->mm);
+	}
+
+	return vma;
+}
+
+static void *m_start(struct seq_file *m, loff_t *ppos)
+{
+	struct proc_maps_private *priv = m->private;
+	unsigned long last_addr = *ppos;
+	struct mm_struct *mm;
+
+	/* See m_next(). Zero at the start or after lseek. */
+	if (last_addr == -1UL)
+		return NULL;
+
+	priv->task = get_proc_task(priv->inode);
+	if (!priv->task)
+		return ERR_PTR(-ESRCH);
+
+	mm = priv->mm;
+	if (!mm || !mmget_not_zero(mm)) {
+		put_task_struct(priv->task);
+		priv->task = NULL;
+		return NULL;
+	}
+
+	if (mmap_read_lock_killable(mm)) {
+		mmput(mm);
+		put_task_struct(priv->task);
+		priv->task = NULL;
+		return ERR_PTR(-EINTR);
+	}
+
+	vma_iter_init(&priv->iter, mm, last_addr);
+	hold_task_mempolicy(priv);
+	if (last_addr == -2UL)
+		return get_gate_vma(mm);
+
+	return proc_get_vma(priv, ppos);
+}
+
+static void *m_next(struct seq_file *m, void *v, loff_t *ppos)
+{
+	if (*ppos == -2UL) {
+		*ppos = -1UL;
+		return NULL;
+	}
+	return proc_get_vma(m->private, ppos);
+}
+
+static void m_stop(struct seq_file *m, void *v)
+{
+	struct proc_maps_private *priv = m->private;
+	struct mm_struct *mm = priv->mm;
+
+	if (!priv->task)
+		return;
+
+	release_task_mempolicy(priv);
+	mmap_read_unlock(mm);
+	mmput(mm);
+	put_task_struct(priv->task);
+	priv->task = NULL;
+}
+
+static int proc_maps_open(struct inode *inode, struct file *file,
+			const struct seq_operations *ops, int psize)
+{
+	struct proc_maps_private *priv = __seq_open_private(file, ops, psize);
+
+	if (!priv)
+		return -ENOMEM;
+
+	priv->inode = inode;
+	priv->mm = proc_mem_open(inode, PTRACE_MODE_READ);
+	if (IS_ERR(priv->mm)) {
+		int err = PTR_ERR(priv->mm);
+
+		seq_release_private(inode, file);
+		return err;
+	}
+
+	return 0;
+}
+
+static int proc_map_release(struct inode *inode, struct file *file)
+{
+	struct seq_file *seq = file->private_data;
+	struct proc_maps_private *priv = seq->private;
+
+	if (priv->mm)
+		mmdrop(priv->mm);
+
+	return seq_release_private(inode, file);
+}
+
+static int do_maps_open(struct inode *inode, struct file *file,
+			const struct seq_operations *ops)
+{
+	return proc_maps_open(inode, file, ops,
+				sizeof(struct proc_maps_private));
+}
+
+/*
+ * Indicate if the VMA is a stack for the given task; for
+ * /proc/PID/maps that is the stack of the main task.
+ */
+static int is_stack(struct vm_area_struct *vma)
+{
+	/*
+	 * We make no effort to guess what a given thread considers to be
+	 * its "stack".  It's not even well-defined for programs written
+	 * languages like Go.
+	 */
+	return vma->vm_start <= vma->vm_mm->start_stack &&
+		vma->vm_end >= vma->vm_mm->start_stack;
+}
+
+static void show_vma_header_prefix(struct seq_file *m,
+				   unsigned long start, unsigned long end,
+				   vm_flags_t flags, unsigned long long pgoff,
+				   dev_t dev, unsigned long ino)
+{
+	seq_setwidth(m, 25 + sizeof(void *) * 6 - 1);
+	seq_put_hex_ll(m, NULL, start, 8);
+	seq_put_hex_ll(m, "-", end, 8);
+	seq_putc(m, ' ');
+	seq_putc(m, flags & VM_READ ? 'r' : '-');
+	seq_putc(m, flags & VM_WRITE ? 'w' : '-');
+	seq_putc(m, flags & VM_EXEC ? 'x' : '-');
+	seq_putc(m, flags & VM_MAYSHARE ? 's' : 'p');
+	seq_put_hex_ll(m, " ", pgoff, 8);
+	seq_put_hex_ll(m, " ", MAJOR(dev), 2);
+	seq_put_hex_ll(m, ":", MINOR(dev), 2);
+	seq_put_decimal_ull(m, " ", ino);
+	seq_putc(m, ' ');
+}
+
+static void
+show_map_vma(struct seq_file *m, struct vm_area_struct *vma)
+{
+	struct mm_struct *mm = vma->vm_mm;
+	struct file *file = vma->vm_file;
+	vm_flags_t flags = vma->vm_flags;
+	unsigned long ino = 0;
+	unsigned long long pgoff = 0;
+	unsigned long start, end;
+	dev_t dev = 0;
+	const char *name = NULL;
+
+	if (file) {
+		struct inode *inode = file_inode(vma->vm_file);
+		dev = inode->i_sb->s_dev;
+		ino = inode->i_ino;
+		pgoff = ((loff_t)vma->vm_pgoff) << PAGE_SHIFT;
+	}
+
+	start = vma->vm_start;
+	end = vma->vm_end;
+	show_vma_header_prefix(m, start, end, flags, pgoff, dev, ino);
+
+	/*
+	 * Print the dentry name for named mappings, and a
+	 * special [heap] marker for the heap:
+	 */
+	if (file) {
+		seq_pad(m, ' ');
+		seq_file_path(m, file, "\n");
+		goto done;
+	}
+
+	if (vma->vm_ops && vma->vm_ops->name) {
+		name = vma->vm_ops->name(vma);
+		if (name)
+			goto done;
+	}
+
+	name = arch_vma_name(vma);
+	if (!name) {
+		struct anon_vma_name *anon_name;
+
+		if (!mm) {
+			name = "[vdso]";
+			goto done;
+		}
+
+		if (vma->vm_start <= mm->brk &&
+		    vma->vm_end >= mm->start_brk) {
+			name = "[heap]";
+			goto done;
+		}
+
+		if (is_stack(vma)) {
+			name = "[stack]";
+			goto done;
+		}
+
+		anon_name = anon_vma_name(vma);
+		if (anon_name) {
+			seq_pad(m, ' ');
+			seq_printf(m, "[anon:%s]", anon_name->name);
+		}
+	}
+
+done:
+	if (name) {
+		seq_pad(m, ' ');
+		seq_puts(m, name);
+	}
+	seq_putc(m, '\n');
+}
+
+static int show_map(struct seq_file *m, void *v)
+{
+	show_map_vma(m, v);
+	return 0;
+}
+
+static const struct seq_operations proc_pid_maps_op = {
+	.start	= m_start,
+	.next	= m_next,
+	.stop	= m_stop,
+	.show	= show_map
+};
+
+static int pid_maps_open(struct inode *inode, struct file *file)
+{
+	return do_maps_open(inode, file, &proc_pid_maps_op);
+}
+
+const struct file_operations proc_pid_maps_operations = {
+	.open		= pid_maps_open,
+	.read		= seq_read,
+	.llseek		= seq_lseek,
+	.release	= proc_map_release,
+};
+
+/*
+ * Proportional Set Size(PSS): my share of RSS.
+ *
+ * PSS of a process is the count of pages it has in memory, where each
+ * page is divided by the number of processes sharing it.  So if a
+ * process has 1000 pages all to itself, and 1000 shared with one other
+ * process, its PSS will be 1500.
+ *
+ * To keep (accumulated) division errors low, we adopt a 64bit
+ * fixed-point pss counter to minimize division errors. So (pss >>
+ * PSS_SHIFT) would be the real byte count.
+ *
+ * A shift of 12 before division means (assuming 4K page size):
+ * 	- 1M 3-user-pages add up to 8KB errors;
+ * 	- supports mapcount up to 2^24, or 16M;
+ * 	- supports PSS up to 2^52 bytes, or 4PB.
+ */
+#define PSS_SHIFT 12
+
+#ifdef CONFIG_PROC_PAGE_MONITOR
+struct mem_size_stats {
+	unsigned long resident;
+	unsigned long shared_clean;
+	unsigned long shared_dirty;
+	unsigned long private_clean;
+	unsigned long private_dirty;
+	unsigned long referenced;
+	unsigned long anonymous;
+	unsigned long lazyfree;
+	unsigned long anonymous_thp;
+	unsigned long shmem_thp;
+	unsigned long file_thp;
+	unsigned long swap;
+	unsigned long shared_hugetlb;
+	unsigned long private_hugetlb;
+	u64 pss;
+	u64 pss_anon;
+	u64 pss_file;
+	u64 pss_shmem;
+	u64 pss_dirty;
+	u64 pss_locked;
+	u64 swap_pss;
+};
+
+static void smaps_page_accumulate(struct mem_size_stats *mss,
+		struct page *page, unsigned long size, unsigned long pss,
+		bool dirty, bool locked, bool private)
+{
+	mss->pss += pss;
+
+	if (PageAnon(page))
+		mss->pss_anon += pss;
+	else if (PageSwapBacked(page))
+		mss->pss_shmem += pss;
+	else
+		mss->pss_file += pss;
+
+	if (locked)
+		mss->pss_locked += pss;
+
+	if (dirty || PageDirty(page)) {
+		mss->pss_dirty += pss;
+		if (private)
+			mss->private_dirty += size;
+		else
+			mss->shared_dirty += size;
+	} else {
+		if (private)
+			mss->private_clean += size;
+		else
+			mss->shared_clean += size;
+	}
+}
+
+static void smaps_account(struct mem_size_stats *mss, struct page *page,
+		bool compound, bool young, bool dirty, bool locked,
+		bool migration)
+{
+	int i, nr = compound ? compound_nr(page) : 1;
+	unsigned long size = nr * PAGE_SIZE;
+
+	/*
+	 * First accumulate quantities that depend only on |size| and the type
+	 * of the compound page.
+	 */
+	if (PageAnon(page)) {
+		mss->anonymous += size;
+		if (!PageSwapBacked(page) && !dirty && !PageDirty(page))
+			mss->lazyfree += size;
+	}
+
+	mss->resident += size;
+	/* Accumulate the size in pages that have been accessed. */
+	if (young || page_is_young(page) || PageReferenced(page))
+		mss->referenced += size;
+
+	/*
+	 * Then accumulate quantities that may depend on sharing, or that may
+	 * differ page-by-page.
+	 *
+	 * page_count(page) == 1 guarantees the page is mapped exactly once.
+	 * If any subpage of the compound page mapped with PTE it would elevate
+	 * page_count().
+	 *
+	 * The page_mapcount() is called to get a snapshot of the mapcount.
+	 * Without holding the page lock this snapshot can be slightly wrong as
+	 * we cannot always read the mapcount atomically.  It is not safe to
+	 * call page_mapcount() even with PTL held if the page is not mapped,
+	 * especially for migration entries.  Treat regular migration entries
+	 * as mapcount == 1.
+	 */
+	if ((page_count(page) == 1) || migration) {
+		smaps_page_accumulate(mss, page, size, size << PSS_SHIFT, dirty,
+			locked, true);
+		return;
+	}
+	for (i = 0; i < nr; i++, page++) {
+		int mapcount = page_mapcount(page);
+		unsigned long pss = PAGE_SIZE << PSS_SHIFT;
+		if (mapcount >= 2)
+			pss /= mapcount;
+		smaps_page_accumulate(mss, page, PAGE_SIZE, pss, dirty, locked,
+				      mapcount < 2);
+	}
+}
+
+#ifdef CONFIG_SHMEM
+static int smaps_pte_hole(unsigned long addr, unsigned long end,
+			  __always_unused int depth, struct mm_walk *walk)
+{
+	struct mem_size_stats *mss = walk->private;
+	struct vm_area_struct *vma = walk->vma;
+
+	mss->swap += shmem_partial_swap_usage(walk->vma->vm_file->f_mapping,
+					      linear_page_index(vma, addr),
+					      linear_page_index(vma, end));
+
+	return 0;
+}
+#else
+#define smaps_pte_hole		NULL
+#endif /* CONFIG_SHMEM */
+
+static void smaps_pte_hole_lookup(unsigned long addr, struct mm_walk *walk)
+{
+#ifdef CONFIG_SHMEM
+	if (walk->ops->pte_hole) {
+		/* depth is not used */
+		smaps_pte_hole(addr, addr + PAGE_SIZE, 0, walk);
+	}
+#endif
+}
+
+static void smaps_pte_entry(pte_t *pte, unsigned long addr,
+		struct mm_walk *walk)
+{
+	struct mem_size_stats *mss = walk->private;
+	struct vm_area_struct *vma = walk->vma;
+	bool locked = !!(vma->vm_flags & VM_LOCKED);
+	struct page *page = NULL;
+	bool migration = false, young = false, dirty = false;
+
+	if (pte_present(*pte)) {
+		page = vm_normal_page(vma, addr, *pte);
+		young = pte_young(*pte);
+		dirty = pte_dirty(*pte);
+	} else if (is_swap_pte(*pte)) {
+		swp_entry_t swpent = pte_to_swp_entry(*pte);
+
+		if (!non_swap_entry(swpent)) {
+			int mapcount;
+
+			mss->swap += PAGE_SIZE;
+			mapcount = swp_swapcount(swpent);
+			if (mapcount >= 2) {
+				u64 pss_delta = (u64)PAGE_SIZE << PSS_SHIFT;
+
+				do_div(pss_delta, mapcount);
+				mss->swap_pss += pss_delta;
+			} else {
+				mss->swap_pss += (u64)PAGE_SIZE << PSS_SHIFT;
+			}
+		} else if (is_pfn_swap_entry(swpent)) {
+			if (is_migration_entry(swpent))
+				migration = true;
+			page = pfn_swap_entry_to_page(swpent);
+		}
+	} else {
+		smaps_pte_hole_lookup(addr, walk);
+		return;
+	}
+
+	if (!page)
+		return;
+
+	smaps_account(mss, page, false, young, dirty, locked, migration);
+}
+
+#ifdef CONFIG_TRANSPARENT_HUGEPAGE
+static void smaps_pmd_entry(pmd_t *pmd, unsigned long addr,
+		struct mm_walk *walk)
+{
+	struct mem_size_stats *mss = walk->private;
+	struct vm_area_struct *vma = walk->vma;
+	bool locked = !!(vma->vm_flags & VM_LOCKED);
+	struct page *page = NULL;
+	bool migration = false;
+
+	if (pmd_present(*pmd)) {
+		/* FOLL_DUMP will return -EFAULT on huge zero page */
+		page = follow_trans_huge_pmd(vma, addr, pmd, FOLL_DUMP);
+	} else if (unlikely(thp_migration_supported() && is_swap_pmd(*pmd))) {
+		swp_entry_t entry = pmd_to_swp_entry(*pmd);
+
+		if (is_migration_entry(entry)) {
+			migration = true;
+			page = pfn_swap_entry_to_page(entry);
+		}
+	}
+	if (IS_ERR_OR_NULL(page))
+		return;
+	if (PageAnon(page))
+		mss->anonymous_thp += HPAGE_PMD_SIZE;
+	else if (PageSwapBacked(page))
+		mss->shmem_thp += HPAGE_PMD_SIZE;
+	else if (is_zone_device_page(page))
+		/* pass */;
+	else
+		mss->file_thp += HPAGE_PMD_SIZE;
+
+	smaps_account(mss, page, true, pmd_young(*pmd), pmd_dirty(*pmd),
+		      locked, migration);
+}
+#else
+static void smaps_pmd_entry(pmd_t *pmd, unsigned long addr,
+		struct mm_walk *walk)
+{
+}
+#endif
+
+static int smaps_pte_range(pmd_t *pmd, unsigned long addr, unsigned long end,
+			   struct mm_walk *walk)
+{
+	struct vm_area_struct *vma = walk->vma;
+	pte_t *pte;
+	spinlock_t *ptl;
+
+	ptl = pmd_trans_huge_lock(pmd, vma);
+	if (ptl) {
+		smaps_pmd_entry(pmd, addr, walk);
+		spin_unlock(ptl);
+		goto out;
+	}
+
+	if (pmd_trans_unstable(pmd))
+		goto out;
+	/*
+	 * The mmap_lock held all the way back in m_start() is what
+	 * keeps khugepaged out of here and from collapsing things
+	 * in here.
+	 */
+	pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl);
+	for (; addr != end; pte++, addr += PAGE_SIZE)
+		smaps_pte_entry(pte, addr, walk);
+	pte_unmap_unlock(pte - 1, ptl);
+out:
+	cond_resched();
+	return 0;
+}
+
+static void show_smap_vma_flags(struct seq_file *m, struct vm_area_struct *vma)
+{
+	/*
+	 * Don't forget to update Documentation/ on changes.
+	 */
+	static const char mnemonics[BITS_PER_LONG][2] = {
+		/*
+		 * In case if we meet a flag we don't know about.
+		 */
+		[0 ... (BITS_PER_LONG-1)] = "??",
+
+		[ilog2(VM_READ)]	= "rd",
+		[ilog2(VM_WRITE)]	= "wr",
+		[ilog2(VM_EXEC)]	= "ex",
+		[ilog2(VM_SHARED)]	= "sh",
+		[ilog2(VM_MAYREAD)]	= "mr",
+		[ilog2(VM_MAYWRITE)]	= "mw",
+		[ilog2(VM_MAYEXEC)]	= "me",
+		[ilog2(VM_MAYSHARE)]	= "ms",
+		[ilog2(VM_GROWSDOWN)]	= "gd",
+		[ilog2(VM_PFNMAP)]	= "pf",
+		[ilog2(VM_LOCKED)]	= "lo",
+		[ilog2(VM_IO)]		= "io",
+		[ilog2(VM_SEQ_READ)]	= "sr",
+		[ilog2(VM_RAND_READ)]	= "rr",
+		[ilog2(VM_DONTCOPY)]	= "dc",
+		[ilog2(VM_DONTEXPAND)]	= "de",
+		[ilog2(VM_ACCOUNT)]	= "ac",
+		[ilog2(VM_NORESERVE)]	= "nr",
+		[ilog2(VM_HUGETLB)]	= "ht",
+		[ilog2(VM_SYNC)]	= "sf",
+		[ilog2(VM_ARCH_1)]	= "ar",
+		[ilog2(VM_WIPEONFORK)]	= "wf",
+		[ilog2(VM_DONTDUMP)]	= "dd",
+#ifdef CONFIG_ARM64_BTI
+		[ilog2(VM_ARM64_BTI)]	= "bt",
+#endif
+#ifdef CONFIG_MEM_SOFT_DIRTY
+		[ilog2(VM_SOFTDIRTY)]	= "sd",
+#endif
+		[ilog2(VM_MIXEDMAP)]	= "mm",
+		[ilog2(VM_HUGEPAGE)]	= "hg",
+		[ilog2(VM_NOHUGEPAGE)]	= "nh",
+		[ilog2(VM_MERGEABLE)]	= "mg",
+		[ilog2(VM_UFFD_MISSING)]= "um",
+		[ilog2(VM_UFFD_WP)]	= "uw",
+#ifdef CONFIG_ARM64_MTE
+		[ilog2(VM_MTE)]		= "mt",
+		[ilog2(VM_MTE_ALLOWED)]	= "",
+#endif
+#ifdef CONFIG_ARCH_HAS_PKEYS
+		/* These come out via ProtectionKey: */
+		[ilog2(VM_PKEY_BIT0)]	= "",
+		[ilog2(VM_PKEY_BIT1)]	= "",
+		[ilog2(VM_PKEY_BIT2)]	= "",
+		[ilog2(VM_PKEY_BIT3)]	= "",
+#if VM_PKEY_BIT4
+		[ilog2(VM_PKEY_BIT4)]	= "",
+#endif
+#endif /* CONFIG_ARCH_HAS_PKEYS */
+#ifdef CONFIG_HAVE_ARCH_USERFAULTFD_MINOR
+		[ilog2(VM_UFFD_MINOR)]	= "ui",
+#endif /* CONFIG_HAVE_ARCH_USERFAULTFD_MINOR */
+	};
+	size_t i;
+
+	seq_puts(m, "VmFlags: ");
+	for (i = 0; i < BITS_PER_LONG; i++) {
+		if (!mnemonics[i][0])
+			continue;
+		if (vma->vm_flags & (1UL << i)) {
+			seq_putc(m, mnemonics[i][0]);
+			seq_putc(m, mnemonics[i][1]);
+			seq_putc(m, ' ');
+		}
+	}
+	seq_putc(m, '\n');
+}
+
+#ifdef CONFIG_HUGETLB_PAGE
+static int smaps_hugetlb_range(pte_t *pte, unsigned long hmask,
+				 unsigned long addr, unsigned long end,
+				 struct mm_walk *walk)
+{
+	struct mem_size_stats *mss = walk->private;
+	struct vm_area_struct *vma = walk->vma;
+	struct page *page = NULL;
+
+	if (pte_present(*pte)) {
+		page = vm_normal_page(vma, addr, *pte);
+	} else if (is_swap_pte(*pte)) {
+		swp_entry_t swpent = pte_to_swp_entry(*pte);
+
+		if (is_pfn_swap_entry(swpent))
+			page = pfn_swap_entry_to_page(swpent);
+	}
+	if (page) {
+		if (page_mapcount(page) >= 2 || hugetlb_pmd_shared(pte))
+			mss->shared_hugetlb += huge_page_size(hstate_vma(vma));
+		else
+			mss->private_hugetlb += huge_page_size(hstate_vma(vma));
+	}
+	return 0;
+}
+#else
+#define smaps_hugetlb_range	NULL
+#endif /* HUGETLB_PAGE */
+
+static const struct mm_walk_ops smaps_walk_ops = {
+	.pmd_entry		= smaps_pte_range,
+	.hugetlb_entry		= smaps_hugetlb_range,
+};
+
+static const struct mm_walk_ops smaps_shmem_walk_ops = {
+	.pmd_entry		= smaps_pte_range,
+	.hugetlb_entry		= smaps_hugetlb_range,
+	.pte_hole		= smaps_pte_hole,
+};
+
+/*
+ * Gather mem stats from @vma with the indicated beginning
+ * address @start, and keep them in @mss.
+ *
+ * Use vm_start of @vma as the beginning address if @start is 0.
+ */
+static void smap_gather_stats(struct vm_area_struct *vma,
+		struct mem_size_stats *mss, unsigned long start)
+{
+	const struct mm_walk_ops *ops = &smaps_walk_ops;
+
+	/* Invalid start */
+	if (start >= vma->vm_end)
+		return;
+
+#ifdef CONFIG_SHMEM
+	if (vma->vm_file && shmem_mapping(vma->vm_file->f_mapping)) {
+		/*
+		 * For shared or readonly shmem mappings we know that all
+		 * swapped out pages belong to the shmem object, and we can
+		 * obtain the swap value much more efficiently. For private
+		 * writable mappings, we might have COW pages that are
+		 * not affected by the parent swapped out pages of the shmem
+		 * object, so we have to distinguish them during the page walk.
+		 * Unless we know that the shmem object (or the part mapped by
+		 * our VMA) has no swapped out pages at all.
+		 */
+		unsigned long shmem_swapped = shmem_swap_usage(vma);
+
+		if (!start && (!shmem_swapped || (vma->vm_flags & VM_SHARED) ||
+					!(vma->vm_flags & VM_WRITE))) {
+			mss->swap += shmem_swapped;
+		} else {
+			ops = &smaps_shmem_walk_ops;
+		}
+	}
+#endif
+	/* mmap_lock is held in m_start */
+	if (!start)
+		walk_page_vma(vma, ops, mss);
+	else
+		walk_page_range(vma->vm_mm, start, vma->vm_end, ops, mss);
+}
+
+#define SEQ_PUT_DEC(str, val) \
+		seq_put_decimal_ull_width(m, str, (val) >> 10, 8)
+
+/* Show the contents common for smaps and smaps_rollup */
+static void __show_smap(struct seq_file *m, const struct mem_size_stats *mss,
+	bool rollup_mode)
+{
+	SEQ_PUT_DEC("Rss:            ", mss->resident);
+	SEQ_PUT_DEC(" kB\nPss:            ", mss->pss >> PSS_SHIFT);
+	SEQ_PUT_DEC(" kB\nPss_Dirty:      ", mss->pss_dirty >> PSS_SHIFT);
+	if (rollup_mode) {
+		/*
+		 * These are meaningful only for smaps_rollup, otherwise two of
+		 * them are zero, and the other one is the same as Pss.
+		 */
+		SEQ_PUT_DEC(" kB\nPss_Anon:       ",
+			mss->pss_anon >> PSS_SHIFT);
+		SEQ_PUT_DEC(" kB\nPss_File:       ",
+			mss->pss_file >> PSS_SHIFT);
+		SEQ_PUT_DEC(" kB\nPss_Shmem:      ",
+			mss->pss_shmem >> PSS_SHIFT);
+	}
+	SEQ_PUT_DEC(" kB\nShared_Clean:   ", mss->shared_clean);
+	SEQ_PUT_DEC(" kB\nShared_Dirty:   ", mss->shared_dirty);
+	SEQ_PUT_DEC(" kB\nPrivate_Clean:  ", mss->private_clean);
+	SEQ_PUT_DEC(" kB\nPrivate_Dirty:  ", mss->private_dirty);
+	SEQ_PUT_DEC(" kB\nReferenced:     ", mss->referenced);
+	SEQ_PUT_DEC(" kB\nAnonymous:      ", mss->anonymous);
+	SEQ_PUT_DEC(" kB\nLazyFree:       ", mss->lazyfree);
+	SEQ_PUT_DEC(" kB\nAnonHugePages:  ", mss->anonymous_thp);
+	SEQ_PUT_DEC(" kB\nShmemPmdMapped: ", mss->shmem_thp);
+	SEQ_PUT_DEC(" kB\nFilePmdMapped:  ", mss->file_thp);
+	SEQ_PUT_DEC(" kB\nShared_Hugetlb: ", mss->shared_hugetlb);
+	seq_put_decimal_ull_width(m, " kB\nPrivate_Hugetlb: ",
+				  mss->private_hugetlb >> 10, 7);
+	SEQ_PUT_DEC(" kB\nSwap:           ", mss->swap);
+	SEQ_PUT_DEC(" kB\nSwapPss:        ",
+					mss->swap_pss >> PSS_SHIFT);
+	SEQ_PUT_DEC(" kB\nLocked:         ",
+					mss->pss_locked >> PSS_SHIFT);
+	seq_puts(m, " kB\n");
+}
+
+static int show_smap(struct seq_file *m, void *v)
+{
+	struct vm_area_struct *vma = v;
+	struct mem_size_stats mss;
+
+	memset(&mss, 0, sizeof(mss));
+
+	smap_gather_stats(vma, &mss, 0);
+
+	show_map_vma(m, vma);
+
+	SEQ_PUT_DEC("Size:           ", vma->vm_end - vma->vm_start);
+	SEQ_PUT_DEC(" kB\nKernelPageSize: ", vma_kernel_pagesize(vma));
+	SEQ_PUT_DEC(" kB\nMMUPageSize:    ", vma_mmu_pagesize(vma));
+	seq_puts(m, " kB\n");
+
+	__show_smap(m, &mss, false);
+
+	seq_printf(m, "THPeligible:    %d\n",
+		   hugepage_vma_check(vma, vma->vm_flags, true, false, true));
+
+	if (arch_pkeys_enabled())
+		seq_printf(m, "ProtectionKey:  %8u\n", vma_pkey(vma));
+	show_smap_vma_flags(m, vma);
+
+	return 0;
+}
+
+static int show_smaps_rollup(struct seq_file *m, void *v)
+{
+	struct proc_maps_private *priv = m->private;
+	struct mem_size_stats mss;
+	struct mm_struct *mm = priv->mm;
+	struct vm_area_struct *vma;
+	unsigned long vma_start = 0, last_vma_end = 0;
+	int ret = 0;
+	MA_STATE(mas, &mm->mm_mt, 0, 0);
+
+	priv->task = get_proc_task(priv->inode);
+	if (!priv->task)
+		return -ESRCH;
+
+	if (!mm || !mmget_not_zero(mm)) {
+		ret = -ESRCH;
+		goto out_put_task;
+	}
+
+	memset(&mss, 0, sizeof(mss));
+
+	ret = mmap_read_lock_killable(mm);
+	if (ret)
+		goto out_put_mm;
+
+	hold_task_mempolicy(priv);
+	vma = mas_find(&mas, ULONG_MAX);
+
+	if (unlikely(!vma))
+		goto empty_set;
+
+	vma_start = vma->vm_start;
+	do {
+		smap_gather_stats(vma, &mss, 0);
+		last_vma_end = vma->vm_end;
+
+		/*
+		 * Release mmap_lock temporarily if someone wants to
+		 * access it for write request.
+		 */
+		if (mmap_lock_is_contended(mm)) {
+			mas_pause(&mas);
+			mmap_read_unlock(mm);
+			ret = mmap_read_lock_killable(mm);
+			if (ret) {
+				release_task_mempolicy(priv);
+				goto out_put_mm;
+			}
+
+			/*
+			 * After dropping the lock, there are four cases to
+			 * consider. See the following example for explanation.
+			 *
+			 *   +------+------+-----------+
+			 *   | VMA1 | VMA2 | VMA3      |
+			 *   +------+------+-----------+
+			 *   |      |      |           |
+			 *  4k     8k     16k         400k
+			 *
+			 * Suppose we drop the lock after reading VMA2 due to
+			 * contention, then we get:
+			 *
+			 *	last_vma_end = 16k
+			 *
+			 * 1) VMA2 is freed, but VMA3 exists:
+			 *
+			 *    find_vma(mm, 16k - 1) will return VMA3.
+			 *    In this case, just continue from VMA3.
+			 *
+			 * 2) VMA2 still exists:
+			 *
+			 *    find_vma(mm, 16k - 1) will return VMA2.
+			 *    Iterate the loop like the original one.
+			 *
+			 * 3) No more VMAs can be found:
+			 *
+			 *    find_vma(mm, 16k - 1) will return NULL.
+			 *    No more things to do, just break.
+			 *
+			 * 4) (last_vma_end - 1) is the middle of a vma (VMA'):
+			 *
+			 *    find_vma(mm, 16k - 1) will return VMA' whose range
+			 *    contains last_vma_end.
+			 *    Iterate VMA' from last_vma_end.
+			 */
+			vma = mas_find(&mas, ULONG_MAX);
+			/* Case 3 above */
+			if (!vma)
+				break;
+
+			/* Case 1 above */
+			if (vma->vm_start >= last_vma_end)
+				continue;
+
+			/* Case 4 above */
+			if (vma->vm_end > last_vma_end)
+				smap_gather_stats(vma, &mss, last_vma_end);
+		}
+		/* Case 2 above */
+	} while ((vma = mas_find(&mas, ULONG_MAX)) != NULL);
+
+empty_set:
+	show_vma_header_prefix(m, vma_start, last_vma_end, 0, 0, 0, 0);
+	seq_pad(m, ' ');
+	seq_puts(m, "[rollup]\n");
+
+	__show_smap(m, &mss, true);
+
+	release_task_mempolicy(priv);
+	mmap_read_unlock(mm);
+
+out_put_mm:
+	mmput(mm);
+out_put_task:
+	put_task_struct(priv->task);
+	priv->task = NULL;
+
+	return ret;
+}
+#undef SEQ_PUT_DEC
+
+static const struct seq_operations proc_pid_smaps_op = {
+	.start	= m_start,
+	.next	= m_next,
+	.stop	= m_stop,
+	.show	= show_smap
+};
+
+static int pid_smaps_open(struct inode *inode, struct file *file)
+{
+	return do_maps_open(inode, file, &proc_pid_smaps_op);
+}
+
+static int smaps_rollup_open(struct inode *inode, struct file *file)
+{
+	int ret;
+	struct proc_maps_private *priv;
+
+	priv = kzalloc(sizeof(*priv), GFP_KERNEL_ACCOUNT);
+	if (!priv)
+		return -ENOMEM;
+
+	ret = single_open(file, show_smaps_rollup, priv);
+	if (ret)
+		goto out_free;
+
+	priv->inode = inode;
+	priv->mm = proc_mem_open(inode, PTRACE_MODE_READ);
+	if (IS_ERR(priv->mm)) {
+		ret = PTR_ERR(priv->mm);
+
+		single_release(inode, file);
+		goto out_free;
+	}
+
+	return 0;
+
+out_free:
+	kfree(priv);
+	return ret;
+}
+
+static int smaps_rollup_release(struct inode *inode, struct file *file)
+{
+	struct seq_file *seq = file->private_data;
+	struct proc_maps_private *priv = seq->private;
+
+	if (priv->mm)
+		mmdrop(priv->mm);
+
+	kfree(priv);
+	return single_release(inode, file);
+}
+
+const struct file_operations proc_pid_smaps_operations = {
+	.open		= pid_smaps_open,
+	.read		= seq_read,
+	.llseek		= seq_lseek,
+	.release	= proc_map_release,
+};
+
+const struct file_operations proc_pid_smaps_rollup_operations = {
+	.open		= smaps_rollup_open,
+	.read		= seq_read,
+	.llseek		= seq_lseek,
+	.release	= smaps_rollup_release,
+};
+
+enum clear_refs_types {
+	CLEAR_REFS_ALL = 1,
+	CLEAR_REFS_ANON,
+	CLEAR_REFS_MAPPED,
+	CLEAR_REFS_SOFT_DIRTY,
+	CLEAR_REFS_MM_HIWATER_RSS,
+	CLEAR_REFS_LAST,
+};
+
+struct clear_refs_private {
+	enum clear_refs_types type;
+};
+
+#ifdef CONFIG_MEM_SOFT_DIRTY
+
+static inline bool pte_is_pinned(struct vm_area_struct *vma, unsigned long addr, pte_t pte)
+{
+	struct page *page;
+
+	if (!pte_write(pte))
+		return false;
+	if (!is_cow_mapping(vma->vm_flags))
+		return false;
+	if (likely(!test_bit(MMF_HAS_PINNED, &vma->vm_mm->flags)))
+		return false;
+	page = vm_normal_page(vma, addr, pte);
+	if (!page)
+		return false;
+	return page_maybe_dma_pinned(page);
+}
+
+static inline void clear_soft_dirty(struct vm_area_struct *vma,
+		unsigned long addr, pte_t *pte)
+{
+	/*
+	 * The soft-dirty tracker uses #PF-s to catch writes
+	 * to pages, so write-protect the pte as well. See the
+	 * Documentation/admin-guide/mm/soft-dirty.rst for full description
+	 * of how soft-dirty works.
+	 */
+	pte_t ptent = *pte;
+
+	if (pte_present(ptent)) {
+		pte_t old_pte;
+
+		if (pte_is_pinned(vma, addr, ptent))
+			return;
+		old_pte = ptep_modify_prot_start(vma, addr, pte);
+		ptent = pte_wrprotect(old_pte);
+		ptent = pte_clear_soft_dirty(ptent);
+		ptep_modify_prot_commit(vma, addr, pte, old_pte, ptent);
+	} else if (is_swap_pte(ptent)) {
+		ptent = pte_swp_clear_soft_dirty(ptent);
+		set_pte_at(vma->vm_mm, addr, pte, ptent);
+	}
+}
+#else
+static inline void clear_soft_dirty(struct vm_area_struct *vma,
+		unsigned long addr, pte_t *pte)
+{
+}
+#endif
+
+#if defined(CONFIG_MEM_SOFT_DIRTY) && defined(CONFIG_TRANSPARENT_HUGEPAGE)
+static inline void clear_soft_dirty_pmd(struct vm_area_struct *vma,
+		unsigned long addr, pmd_t *pmdp)
+{
+	pmd_t old, pmd = *pmdp;
+
+	if (pmd_present(pmd)) {
+		/* See comment in change_huge_pmd() */
+		old = pmdp_invalidate(vma, addr, pmdp);
+		if (pmd_dirty(old))
+			pmd = pmd_mkdirty(pmd);
+		if (pmd_young(old))
+			pmd = pmd_mkyoung(pmd);
+
+		pmd = pmd_wrprotect(pmd);
+		pmd = pmd_clear_soft_dirty(pmd);
+
+		set_pmd_at(vma->vm_mm, addr, pmdp, pmd);
+	} else if (is_migration_entry(pmd_to_swp_entry(pmd))) {
+		pmd = pmd_swp_clear_soft_dirty(pmd);
+		set_pmd_at(vma->vm_mm, addr, pmdp, pmd);
+	}
+}
+#else
+static inline void clear_soft_dirty_pmd(struct vm_area_struct *vma,
+		unsigned long addr, pmd_t *pmdp)
+{
+}
+#endif
+
+static int clear_refs_pte_range(pmd_t *pmd, unsigned long addr,
+				unsigned long end, struct mm_walk *walk)
+{
+	struct clear_refs_private *cp = walk->private;
+	struct vm_area_struct *vma = walk->vma;
+	pte_t *pte, ptent;
+	spinlock_t *ptl;
+	struct page *page;
+
+	ptl = pmd_trans_huge_lock(pmd, vma);
+	if (ptl) {
+		if (cp->type == CLEAR_REFS_SOFT_DIRTY) {
+			clear_soft_dirty_pmd(vma, addr, pmd);
+			goto out;
+		}
+
+		if (!pmd_present(*pmd))
+			goto out;
+
+		page = pmd_page(*pmd);
+
+		/* Clear accessed and referenced bits. */
+		pmdp_test_and_clear_young(vma, addr, pmd);
+		test_and_clear_page_young(page);
+		ClearPageReferenced(page);
+out:
+		spin_unlock(ptl);
+		return 0;
+	}
+
+	if (pmd_trans_unstable(pmd))
+		return 0;
+
+	pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl);
+	for (; addr != end; pte++, addr += PAGE_SIZE) {
+		ptent = *pte;
+
+		if (cp->type == CLEAR_REFS_SOFT_DIRTY) {
+			clear_soft_dirty(vma, addr, pte);
+			continue;
+		}
+
+		if (!pte_present(ptent))
+			continue;
+
+		page = vm_normal_page(vma, addr, ptent);
+		if (!page)
+			continue;
+
+		/* Clear accessed and referenced bits. */
+		ptep_test_and_clear_young(vma, addr, pte);
+		test_and_clear_page_young(page);
+		ClearPageReferenced(page);
+	}
+	pte_unmap_unlock(pte - 1, ptl);
+	cond_resched();
+	return 0;
+}
+
+static int clear_refs_test_walk(unsigned long start, unsigned long end,
+				struct mm_walk *walk)
+{
+	struct clear_refs_private *cp = walk->private;
+	struct vm_area_struct *vma = walk->vma;
+
+	if (vma->vm_flags & VM_PFNMAP)
+		return 1;
+
+	/*
+	 * Writing 1 to /proc/pid/clear_refs affects all pages.
+	 * Writing 2 to /proc/pid/clear_refs only affects anonymous pages.
+	 * Writing 3 to /proc/pid/clear_refs only affects file mapped pages.
+	 * Writing 4 to /proc/pid/clear_refs affects all pages.
+	 */
+	if (cp->type == CLEAR_REFS_ANON && vma->vm_file)
+		return 1;
+	if (cp->type == CLEAR_REFS_MAPPED && !vma->vm_file)
+		return 1;
+	return 0;
+}
+
+static const struct mm_walk_ops clear_refs_walk_ops = {
+	.pmd_entry		= clear_refs_pte_range,
+	.test_walk		= clear_refs_test_walk,
+};
+
+static ssize_t clear_refs_write(struct file *file, const char __user *buf,
+				size_t count, loff_t *ppos)
+{
+	struct task_struct *task;
+	char buffer[PROC_NUMBUF];
+	struct mm_struct *mm;
+	struct vm_area_struct *vma;
+	enum clear_refs_types type;
+	int itype;
+	int rv;
+
+	memset(buffer, 0, sizeof(buffer));
+	if (count > sizeof(buffer) - 1)
+		count = sizeof(buffer) - 1;
+	if (copy_from_user(buffer, buf, count))
+		return -EFAULT;
+	rv = kstrtoint(strstrip(buffer), 10, &itype);
+	if (rv < 0)
+		return rv;
+	type = (enum clear_refs_types)itype;
+	if (type < CLEAR_REFS_ALL || type >= CLEAR_REFS_LAST)
+		return -EINVAL;
+
+	task = get_proc_task(file_inode(file));
+	if (!task)
+		return -ESRCH;
+	mm = get_task_mm(task);
+	if (mm) {
+		MA_STATE(mas, &mm->mm_mt, 0, 0);
+		struct mmu_notifier_range range;
+		struct clear_refs_private cp = {
+			.type = type,
+		};
+
+		if (mmap_write_lock_killable(mm)) {
+			count = -EINTR;
+			goto out_mm;
+		}
+		if (type == CLEAR_REFS_MM_HIWATER_RSS) {
+			/*
+			 * Writing 5 to /proc/pid/clear_refs resets the peak
+			 * resident set size to this mm's current rss value.
+			 */
+			reset_mm_hiwater_rss(mm);
+			goto out_unlock;
+		}
+
+		if (type == CLEAR_REFS_SOFT_DIRTY) {
+			mas_for_each(&mas, vma, ULONG_MAX) {
+				if (!(vma->vm_flags & VM_SOFTDIRTY))
+					continue;
+				vma->vm_flags &= ~VM_SOFTDIRTY;
+				vma_set_page_prot(vma);
+			}
+
+			inc_tlb_flush_pending(mm);
+			mmu_notifier_range_init(&range, MMU_NOTIFY_SOFT_DIRTY,
+						0, NULL, mm, 0, -1UL);
+			mmu_notifier_invalidate_range_start(&range);
+		}
+		walk_page_range(mm, 0, -1, &clear_refs_walk_ops, &cp);
+		if (type == CLEAR_REFS_SOFT_DIRTY) {
+			mmu_notifier_invalidate_range_end(&range);
+			flush_tlb_mm(mm);
+			dec_tlb_flush_pending(mm);
+		}
+out_unlock:
+		mmap_write_unlock(mm);
+out_mm:
+		mmput(mm);
+	}
+	put_task_struct(task);
+
+	return count;
+}
+
+const struct file_operations proc_clear_refs_operations = {
+	.write		= clear_refs_write,
+	.llseek		= noop_llseek,
+};
+
+typedef struct {
+	u64 pme;
+} pagemap_entry_t;
+
+struct pagemapread {
+	int pos, len;		/* units: PM_ENTRY_BYTES, not bytes */
+	pagemap_entry_t *buffer;
+	bool show_pfn;
+};
+
+#define PAGEMAP_WALK_SIZE	(PMD_SIZE)
+#define PAGEMAP_WALK_MASK	(PMD_MASK)
+
+#define PM_ENTRY_BYTES		sizeof(pagemap_entry_t)
+#define PM_PFRAME_BITS		55
+#define PM_PFRAME_MASK		GENMASK_ULL(PM_PFRAME_BITS - 1, 0)
+#define PM_SOFT_DIRTY		BIT_ULL(55)
+#define PM_MMAP_EXCLUSIVE	BIT_ULL(56)
+#define PM_UFFD_WP		BIT_ULL(57)
+#define PM_FILE			BIT_ULL(61)
+#define PM_SWAP			BIT_ULL(62)
+#define PM_PRESENT		BIT_ULL(63)
+
+#define PM_END_OF_BUFFER    1
+
+static inline pagemap_entry_t make_pme(u64 frame, u64 flags)
+{
+	return (pagemap_entry_t) { .pme = (frame & PM_PFRAME_MASK) | flags };
+}
+
+static int add_to_pagemap(unsigned long addr, pagemap_entry_t *pme,
+			  struct pagemapread *pm)
+{
+	pm->buffer[pm->pos++] = *pme;
+	if (pm->pos >= pm->len)
+		return PM_END_OF_BUFFER;
+	return 0;
+}
+
+static int pagemap_pte_hole(unsigned long start, unsigned long end,
+			    __always_unused int depth, struct mm_walk *walk)
+{
+	struct pagemapread *pm = walk->private;
+	unsigned long addr = start;
+	int err = 0;
+
+	while (addr < end) {
+		struct vm_area_struct *vma = find_vma(walk->mm, addr);
+		pagemap_entry_t pme = make_pme(0, 0);
+		/* End of address space hole, which we mark as non-present. */
+		unsigned long hole_end;
+
+		if (vma)
+			hole_end = min(end, vma->vm_start);
+		else
+			hole_end = end;
+
+		for (; addr < hole_end; addr += PAGE_SIZE) {
+			err = add_to_pagemap(addr, &pme, pm);
+			if (err)
+				goto out;
+		}
+
+		if (!vma)
+			break;
+
+		/* Addresses in the VMA. */
+		if (vma->vm_flags & VM_SOFTDIRTY)
+			pme = make_pme(0, PM_SOFT_DIRTY);
+		for (; addr < min(end, vma->vm_end); addr += PAGE_SIZE) {
+			err = add_to_pagemap(addr, &pme, pm);
+			if (err)
+				goto out;
+		}
+	}
+out:
+	return err;
+}
+
+static pagemap_entry_t pte_to_pagemap_entry(struct pagemapread *pm,
+		struct vm_area_struct *vma, unsigned long addr, pte_t pte)
+{
+	u64 frame = 0, flags = 0;
+	struct page *page = NULL;
+	bool migration = false;
+
+	if (pte_present(pte)) {
+		if (pm->show_pfn)
+			frame = pte_pfn(pte);
+		flags |= PM_PRESENT;
+		page = vm_normal_page(vma, addr, pte);
+		if (pte_soft_dirty(pte))
+			flags |= PM_SOFT_DIRTY;
+		if (pte_uffd_wp(pte))
+			flags |= PM_UFFD_WP;
+	} else if (is_swap_pte(pte)) {
+		swp_entry_t entry;
+		if (pte_swp_soft_dirty(pte))
+			flags |= PM_SOFT_DIRTY;
+		if (pte_swp_uffd_wp(pte))
+			flags |= PM_UFFD_WP;
+		entry = pte_to_swp_entry(pte);
+		if (pm->show_pfn) {
+			pgoff_t offset;
+			/*
+			 * For PFN swap offsets, keeping the offset field
+			 * to be PFN only to be compatible with old smaps.
+			 */
+			if (is_pfn_swap_entry(entry))
+				offset = swp_offset_pfn(entry);
+			else
+				offset = swp_offset(entry);
+			frame = swp_type(entry) |
+			    (offset << MAX_SWAPFILES_SHIFT);
+		}
+		flags |= PM_SWAP;
+		migration = is_migration_entry(entry);
+		if (is_pfn_swap_entry(entry))
+			page = pfn_swap_entry_to_page(entry);
+		if (pte_marker_entry_uffd_wp(entry))
+			flags |= PM_UFFD_WP;
+	}
+
+	if (page && !PageAnon(page))
+		flags |= PM_FILE;
+	if (page && !migration && page_mapcount(page) == 1)
+		flags |= PM_MMAP_EXCLUSIVE;
+	if (vma->vm_flags & VM_SOFTDIRTY)
+		flags |= PM_SOFT_DIRTY;
+
+	return make_pme(frame, flags);
+}
+
+static int pagemap_pmd_range(pmd_t *pmdp, unsigned long addr, unsigned long end,
+			     struct mm_walk *walk)
+{
+	struct vm_area_struct *vma = walk->vma;
+	struct pagemapread *pm = walk->private;
+	spinlock_t *ptl;
+	pte_t *pte, *orig_pte;
+	int err = 0;
+#ifdef CONFIG_TRANSPARENT_HUGEPAGE
+	bool migration = false;
+
+	ptl = pmd_trans_huge_lock(pmdp, vma);
+	if (ptl) {
+		u64 flags = 0, frame = 0;
+		pmd_t pmd = *pmdp;
+		struct page *page = NULL;
+
+		if (vma->vm_flags & VM_SOFTDIRTY)
+			flags |= PM_SOFT_DIRTY;
+
+		if (pmd_present(pmd)) {
+			page = pmd_page(pmd);
+
+			flags |= PM_PRESENT;
+			if (pmd_soft_dirty(pmd))
+				flags |= PM_SOFT_DIRTY;
+			if (pmd_uffd_wp(pmd))
+				flags |= PM_UFFD_WP;
+			if (pm->show_pfn)
+				frame = pmd_pfn(pmd) +
+					((addr & ~PMD_MASK) >> PAGE_SHIFT);
+		}
+#ifdef CONFIG_ARCH_ENABLE_THP_MIGRATION
+		else if (is_swap_pmd(pmd)) {
+			swp_entry_t entry = pmd_to_swp_entry(pmd);
+			unsigned long offset;
+
+			if (pm->show_pfn) {
+				if (is_pfn_swap_entry(entry))
+					offset = swp_offset_pfn(entry);
+				else
+					offset = swp_offset(entry);
+				offset = offset +
+					((addr & ~PMD_MASK) >> PAGE_SHIFT);
+				frame = swp_type(entry) |
+					(offset << MAX_SWAPFILES_SHIFT);
+			}
+			flags |= PM_SWAP;
+			if (pmd_swp_soft_dirty(pmd))
+				flags |= PM_SOFT_DIRTY;
+			if (pmd_swp_uffd_wp(pmd))
+				flags |= PM_UFFD_WP;
+			VM_BUG_ON(!is_pmd_migration_entry(pmd));
+			migration = is_migration_entry(entry);
+			page = pfn_swap_entry_to_page(entry);
+		}
+#endif
+
+		if (page && !migration && page_mapcount(page) == 1)
+			flags |= PM_MMAP_EXCLUSIVE;
+
+		for (; addr != end; addr += PAGE_SIZE) {
+			pagemap_entry_t pme = make_pme(frame, flags);
+
+			err = add_to_pagemap(addr, &pme, pm);
+			if (err)
+				break;
+			if (pm->show_pfn) {
+				if (flags & PM_PRESENT)
+					frame++;
+				else if (flags & PM_SWAP)
+					frame += (1 << MAX_SWAPFILES_SHIFT);
+			}
+		}
+		spin_unlock(ptl);
+		return err;
+	}
+
+	if (pmd_trans_unstable(pmdp))
+		return 0;
+#endif /* CONFIG_TRANSPARENT_HUGEPAGE */
+
+	/*
+	 * We can assume that @vma always points to a valid one and @end never
+	 * goes beyond vma->vm_end.
+	 */
+	orig_pte = pte = pte_offset_map_lock(walk->mm, pmdp, addr, &ptl);
+	for (; addr < end; pte++, addr += PAGE_SIZE) {
+		pagemap_entry_t pme;
+
+		pme = pte_to_pagemap_entry(pm, vma, addr, *pte);
+		err = add_to_pagemap(addr, &pme, pm);
+		if (err)
+			break;
+	}
+	pte_unmap_unlock(orig_pte, ptl);
+
+	cond_resched();
+
+	return err;
+}
+
+#ifdef CONFIG_HUGETLB_PAGE
+/* This function walks within one hugetlb entry in the single call */
+static int pagemap_hugetlb_range(pte_t *ptep, unsigned long hmask,
+				 unsigned long addr, unsigned long end,
+				 struct mm_walk *walk)
+{
+	struct pagemapread *pm = walk->private;
+	struct vm_area_struct *vma = walk->vma;
+	u64 flags = 0, frame = 0;
+	int err = 0;
+	pte_t pte;
+
+	if (vma->vm_flags & VM_SOFTDIRTY)
+		flags |= PM_SOFT_DIRTY;
+
+	pte = huge_ptep_get(ptep);
+	if (pte_present(pte)) {
+		struct page *page = pte_page(pte);
+
+		if (!PageAnon(page))
+			flags |= PM_FILE;
+
+		if (page_mapcount(page) == 1)
+			flags |= PM_MMAP_EXCLUSIVE;
+
+		if (huge_pte_uffd_wp(pte))
+			flags |= PM_UFFD_WP;
+
+		flags |= PM_PRESENT;
+		if (pm->show_pfn)
+			frame = pte_pfn(pte) +
+				((addr & ~hmask) >> PAGE_SHIFT);
+	} else if (pte_swp_uffd_wp_any(pte)) {
+		flags |= PM_UFFD_WP;
+	}
+
+	for (; addr != end; addr += PAGE_SIZE) {
+		pagemap_entry_t pme = make_pme(frame, flags);
+
+		err = add_to_pagemap(addr, &pme, pm);
+		if (err)
+			return err;
+		if (pm->show_pfn && (flags & PM_PRESENT))
+			frame++;
+	}
+
+	cond_resched();
+
+	return err;
+}
+#else
+#define pagemap_hugetlb_range	NULL
+#endif /* HUGETLB_PAGE */
+
+static const struct mm_walk_ops pagemap_ops = {
+	.pmd_entry	= pagemap_pmd_range,
+	.pte_hole	= pagemap_pte_hole,
+	.hugetlb_entry	= pagemap_hugetlb_range,
+};
+
+/*
+ * /proc/pid/pagemap - an array mapping virtual pages to pfns
+ *
+ * For each page in the address space, this file contains one 64-bit entry
+ * consisting of the following:
+ *
+ * Bits 0-54  page frame number (PFN) if present
+ * Bits 0-4   swap type if swapped
+ * Bits 5-54  swap offset if swapped
+ * Bit  55    pte is soft-dirty (see Documentation/admin-guide/mm/soft-dirty.rst)
+ * Bit  56    page exclusively mapped
+ * Bit  57    pte is uffd-wp write-protected
+ * Bits 58-60 zero
+ * Bit  61    page is file-page or shared-anon
+ * Bit  62    page swapped
+ * Bit  63    page present
+ *
+ * If the page is not present but in swap, then the PFN contains an
+ * encoding of the swap file number and the page's offset into the
+ * swap. Unmapped pages return a null PFN. This allows determining
+ * precisely which pages are mapped (or in swap) and comparing mapped
+ * pages between processes.
+ *
+ * Efficient users of this interface will use /proc/pid/maps to
+ * determine which areas of memory are actually mapped and llseek to
+ * skip over unmapped regions.
+ */
+static ssize_t pagemap_read(struct file *file, char __user *buf,
+			    size_t count, loff_t *ppos)
+{
+	struct mm_struct *mm = file->private_data;
+	struct pagemapread pm;
+	unsigned long src;
+	unsigned long svpfn;
+	unsigned long start_vaddr;
+	unsigned long end_vaddr;
+	int ret = 0, copied = 0;
+
+	if (!mm || !mmget_not_zero(mm))
+		goto out;
+
+	ret = -EINVAL;
+	/* file position must be aligned */
+	if ((*ppos % PM_ENTRY_BYTES) || (count % PM_ENTRY_BYTES))
+		goto out_mm;
+
+	ret = 0;
+	if (!count)
+		goto out_mm;
+
+	/* do not disclose physical addresses: attack vector */
+	pm.show_pfn = file_ns_capable(file, &init_user_ns, CAP_SYS_ADMIN);
+
+	pm.len = (PAGEMAP_WALK_SIZE >> PAGE_SHIFT);
+	pm.buffer = kmalloc_array(pm.len, PM_ENTRY_BYTES, GFP_KERNEL);
+	ret = -ENOMEM;
+	if (!pm.buffer)
+		goto out_mm;
+
+	src = *ppos;
+	svpfn = src / PM_ENTRY_BYTES;
+	end_vaddr = mm->task_size;
+
+	/* watch out for wraparound */
+	start_vaddr = end_vaddr;
+	if (svpfn <= (ULONG_MAX >> PAGE_SHIFT))
+		start_vaddr = untagged_addr(svpfn << PAGE_SHIFT);
+
+	/* Ensure the address is inside the task */
+	if (start_vaddr > mm->task_size)
+		start_vaddr = end_vaddr;
+
+	/*
+	 * The odds are that this will stop walking way
+	 * before end_vaddr, because the length of the
+	 * user buffer is tracked in "pm", and the walk
+	 * will stop when we hit the end of the buffer.
+	 */
+	ret = 0;
+	while (count && (start_vaddr < end_vaddr)) {
+		int len;
+		unsigned long end;
+
+		pm.pos = 0;
+		end = (start_vaddr + PAGEMAP_WALK_SIZE) & PAGEMAP_WALK_MASK;
+		/* overflow ? */
+		if (end < start_vaddr || end > end_vaddr)
+			end = end_vaddr;
+		ret = mmap_read_lock_killable(mm);
+		if (ret)
+			goto out_free;
+		ret = walk_page_range(mm, start_vaddr, end, &pagemap_ops, &pm);
+		mmap_read_unlock(mm);
+		start_vaddr = end;
+
+		len = min(count, PM_ENTRY_BYTES * pm.pos);
+		if (copy_to_user(buf, pm.buffer, len)) {
+			ret = -EFAULT;
+			goto out_free;
+		}
+		copied += len;
+		buf += len;
+		count -= len;
+	}
+	*ppos += copied;
+	if (!ret || ret == PM_END_OF_BUFFER)
+		ret = copied;
+
+out_free:
+	kfree(pm.buffer);
+out_mm:
+	mmput(mm);
+out:
+	return ret;
+}
+
+static int pagemap_open(struct inode *inode, struct file *file)
+{
+	struct mm_struct *mm;
+
+	mm = proc_mem_open(inode, PTRACE_MODE_READ);
+	if (IS_ERR(mm))
+		return PTR_ERR(mm);
+	file->private_data = mm;
+	return 0;
+}
+
+static int pagemap_release(struct inode *inode, struct file *file)
+{
+	struct mm_struct *mm = file->private_data;
+
+	if (mm)
+		mmdrop(mm);
+	return 0;
+}
+
+const struct file_operations proc_pagemap_operations = {
+	.llseek		= mem_lseek, /* borrow this */
+	.read		= pagemap_read,
+	.open		= pagemap_open,
+	.release	= pagemap_release,
+};
+#endif /* CONFIG_PROC_PAGE_MONITOR */
+
+#ifdef CONFIG_NUMA
+
+struct numa_maps {
+	unsigned long pages;
+	unsigned long anon;
+	unsigned long active;
+	unsigned long writeback;
+	unsigned long mapcount_max;
+	unsigned long dirty;
+	unsigned long swapcache;
+	unsigned long node[MAX_NUMNODES];
+};
+
+struct numa_maps_private {
+	struct proc_maps_private proc_maps;
+	struct numa_maps md;
+};
+
+static void gather_stats(struct page *page, struct numa_maps *md, int pte_dirty,
+			unsigned long nr_pages)
+{
+	int count = page_mapcount(page);
+
+	md->pages += nr_pages;
+	if (pte_dirty || PageDirty(page))
+		md->dirty += nr_pages;
+
+	if (PageSwapCache(page))
+		md->swapcache += nr_pages;
+
+	if (PageActive(page) || PageUnevictable(page))
+		md->active += nr_pages;
+
+	if (PageWriteback(page))
+		md->writeback += nr_pages;
+
+	if (PageAnon(page))
+		md->anon += nr_pages;
+
+	if (count > md->mapcount_max)
+		md->mapcount_max = count;
+
+	md->node[page_to_nid(page)] += nr_pages;
+}
+
+static struct page *can_gather_numa_stats(pte_t pte, struct vm_area_struct *vma,
+		unsigned long addr)
+{
+	struct page *page;
+	int nid;
+
+	if (!pte_present(pte))
+		return NULL;
+
+	page = vm_normal_page(vma, addr, pte);
+	if (!page || is_zone_device_page(page))
+		return NULL;
+
+	if (PageReserved(page))
+		return NULL;
+
+	nid = page_to_nid(page);
+	if (!node_isset(nid, node_states[N_MEMORY]))
+		return NULL;
+
+	return page;
+}
+
+#ifdef CONFIG_TRANSPARENT_HUGEPAGE
+static struct page *can_gather_numa_stats_pmd(pmd_t pmd,
+					      struct vm_area_struct *vma,
+					      unsigned long addr)
+{
+	struct page *page;
+	int nid;
+
+	if (!pmd_present(pmd))
+		return NULL;
+
+	page = vm_normal_page_pmd(vma, addr, pmd);
+	if (!page)
+		return NULL;
+
+	if (PageReserved(page))
+		return NULL;
+
+	nid = page_to_nid(page);
+	if (!node_isset(nid, node_states[N_MEMORY]))
+		return NULL;
+
+	return page;
+}
+#endif
+
+static int gather_pte_stats(pmd_t *pmd, unsigned long addr,
+		unsigned long end, struct mm_walk *walk)
+{
+	struct numa_maps *md = walk->private;
+	struct vm_area_struct *vma = walk->vma;
+	spinlock_t *ptl;
+	pte_t *orig_pte;
+	pte_t *pte;
+
+#ifdef CONFIG_TRANSPARENT_HUGEPAGE
+	ptl = pmd_trans_huge_lock(pmd, vma);
+	if (ptl) {
+		struct page *page;
+
+		page = can_gather_numa_stats_pmd(*pmd, vma, addr);
+		if (page)
+			gather_stats(page, md, pmd_dirty(*pmd),
+				     HPAGE_PMD_SIZE/PAGE_SIZE);
+		spin_unlock(ptl);
+		return 0;
+	}
+
+	if (pmd_trans_unstable(pmd))
+		return 0;
+#endif
+	orig_pte = pte = pte_offset_map_lock(walk->mm, pmd, addr, &ptl);
+	do {
+		struct page *page = can_gather_numa_stats(*pte, vma, addr);
+		if (!page)
+			continue;
+		gather_stats(page, md, pte_dirty(*pte), 1);
+
+	} while (pte++, addr += PAGE_SIZE, addr != end);
+	pte_unmap_unlock(orig_pte, ptl);
+	cond_resched();
+	return 0;
+}
+#ifdef CONFIG_HUGETLB_PAGE
+static int gather_hugetlb_stats(pte_t *pte, unsigned long hmask,
+		unsigned long addr, unsigned long end, struct mm_walk *walk)
+{
+	pte_t huge_pte = huge_ptep_get(pte);
+	struct numa_maps *md;
+	struct page *page;
+
+	if (!pte_present(huge_pte))
+		return 0;
+
+	page = pte_page(huge_pte);
+
+	md = walk->private;
+	gather_stats(page, md, pte_dirty(huge_pte), 1);
+	return 0;
+}
+
+#else
+static int gather_hugetlb_stats(pte_t *pte, unsigned long hmask,
+		unsigned long addr, unsigned long end, struct mm_walk *walk)
+{
+	return 0;
+}
+#endif
+
+static const struct mm_walk_ops show_numa_ops = {
+	.hugetlb_entry = gather_hugetlb_stats,
+	.pmd_entry = gather_pte_stats,
+};
+
+/*
+ * Display pages allocated per node and memory policy via /proc.
+ */
+static int show_numa_map(struct seq_file *m, void *v)
+{
+	struct numa_maps_private *numa_priv = m->private;
+	struct proc_maps_private *proc_priv = &numa_priv->proc_maps;
+	struct vm_area_struct *vma = v;
+	struct numa_maps *md = &numa_priv->md;
+	struct file *file = vma->vm_file;
+	struct mm_struct *mm = vma->vm_mm;
+	struct mempolicy *pol;
+	char buffer[64];
+	int nid;
+
+	if (!mm)
+		return 0;
+
+	/* Ensure we start with an empty set of numa_maps statistics. */
+	memset(md, 0, sizeof(*md));
+
+	pol = __get_vma_policy(vma, vma->vm_start);
+	if (pol) {
+		mpol_to_str(buffer, sizeof(buffer), pol);
+		mpol_cond_put(pol);
+	} else {
+		mpol_to_str(buffer, sizeof(buffer), proc_priv->task_mempolicy);
+	}
+
+	seq_printf(m, "%08lx %s", vma->vm_start, buffer);
+
+	if (file) {
+		seq_puts(m, " file=");
+		seq_file_path(m, file, "\n\t= ");
+	} else if (vma->vm_start <= mm->brk && vma->vm_end >= mm->start_brk) {
+		seq_puts(m, " heap");
+	} else if (is_stack(vma)) {
+		seq_puts(m, " stack");
+	}
+
+	if (is_vm_hugetlb_page(vma))
+		seq_puts(m, " huge");
+
+	/* mmap_lock is held by m_start */
+	walk_page_vma(vma, &show_numa_ops, md);
+
+	if (!md->pages)
+		goto out;
+
+	if (md->anon)
+		seq_printf(m, " anon=%lu", md->anon);
+
+	if (md->dirty)
+		seq_printf(m, " dirty=%lu", md->dirty);
+
+	if (md->pages != md->anon && md->pages != md->dirty)
+		seq_printf(m, " mapped=%lu", md->pages);
+
+	if (md->mapcount_max > 1)
+		seq_printf(m, " mapmax=%lu", md->mapcount_max);
+
+	if (md->swapcache)
+		seq_printf(m, " swapcache=%lu", md->swapcache);
+
+	if (md->active < md->pages && !is_vm_hugetlb_page(vma))
+		seq_printf(m, " active=%lu", md->active);
+
+	if (md->writeback)
+		seq_printf(m, " writeback=%lu", md->writeback);
+
+	for_each_node_state(nid, N_MEMORY)
+		if (md->node[nid])
+			seq_printf(m, " N%d=%lu", nid, md->node[nid]);
+
+	seq_printf(m, " kernelpagesize_kB=%lu", vma_kernel_pagesize(vma) >> 10);
+out:
+	seq_putc(m, '\n');
+	return 0;
+}
+
+static const struct seq_operations proc_pid_numa_maps_op = {
+	.start  = m_start,
+	.next   = m_next,
+	.stop   = m_stop,
+	.show   = show_numa_map,
+};
+
+static int pid_numa_maps_open(struct inode *inode, struct file *file)
+{
+	return proc_maps_open(inode, file, &proc_pid_numa_maps_op,
+				sizeof(struct numa_maps_private));
+}
+
+const struct file_operations proc_pid_numa_maps_operations = {
+	.open		= pid_numa_maps_open,
+	.read		= seq_read,
+	.llseek		= seq_lseek,
+	.release	= proc_map_release,
+};
+
+#endif /* CONFIG_NUMA */
diff --git a/fs/proc/task_nommu.c b/fs/proc/task_nommu.c
new file mode 100644
index 000000000..dc05780f9
--- /dev/null
+++ b/fs/proc/task_nommu.c
@@ -0,0 +1,309 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/mm.h>
+#include <linux/file.h>
+#include <linux/fdtable.h>
+#include <linux/fs_struct.h>
+#include <linux/mount.h>
+#include <linux/ptrace.h>
+#include <linux/slab.h>
+#include <linux/seq_file.h>
+#include <linux/sched/mm.h>
+
+#include "internal.h"
+
+/*
+ * Logic: we've got two memory sums for each process, "shared", and
+ * "non-shared". Shared memory may get counted more than once, for
+ * each process that owns it. Non-shared memory is counted
+ * accurately.
+ */
+void task_mem(struct seq_file *m, struct mm_struct *mm)
+{
+	VMA_ITERATOR(vmi, mm, 0);
+	struct vm_area_struct *vma;
+	struct vm_region *region;
+	unsigned long bytes = 0, sbytes = 0, slack = 0, size;
+
+	mmap_read_lock(mm);
+	for_each_vma(vmi, vma) {
+		bytes += kobjsize(vma);
+
+		region = vma->vm_region;
+		if (region) {
+			size = kobjsize(region);
+			size += region->vm_end - region->vm_start;
+		} else {
+			size = vma->vm_end - vma->vm_start;
+		}
+
+		if (atomic_read(&mm->mm_count) > 1 ||
+		    vma->vm_flags & VM_MAYSHARE) {
+			sbytes += size;
+		} else {
+			bytes += size;
+			if (region)
+				slack = region->vm_end - vma->vm_end;
+		}
+	}
+
+	if (atomic_read(&mm->mm_count) > 1)
+		sbytes += kobjsize(mm);
+	else
+		bytes += kobjsize(mm);
+	
+	if (current->fs && current->fs->users > 1)
+		sbytes += kobjsize(current->fs);
+	else
+		bytes += kobjsize(current->fs);
+
+	if (current->files && atomic_read(&current->files->count) > 1)
+		sbytes += kobjsize(current->files);
+	else
+		bytes += kobjsize(current->files);
+
+	if (current->sighand && refcount_read(&current->sighand->count) > 1)
+		sbytes += kobjsize(current->sighand);
+	else
+		bytes += kobjsize(current->sighand);
+
+	bytes += kobjsize(current); /* includes kernel stack */
+
+	seq_printf(m,
+		"Mem:\t%8lu bytes\n"
+		"Slack:\t%8lu bytes\n"
+		"Shared:\t%8lu bytes\n",
+		bytes, slack, sbytes);
+
+	mmap_read_unlock(mm);
+}
+
+unsigned long task_vsize(struct mm_struct *mm)
+{
+	VMA_ITERATOR(vmi, mm, 0);
+	struct vm_area_struct *vma;
+	unsigned long vsize = 0;
+
+	mmap_read_lock(mm);
+	for_each_vma(vmi, vma)
+		vsize += vma->vm_end - vma->vm_start;
+	mmap_read_unlock(mm);
+	return vsize;
+}
+
+unsigned long task_statm(struct mm_struct *mm,
+			 unsigned long *shared, unsigned long *text,
+			 unsigned long *data, unsigned long *resident)
+{
+	VMA_ITERATOR(vmi, mm, 0);
+	struct vm_area_struct *vma;
+	struct vm_region *region;
+	unsigned long size = kobjsize(mm);
+
+	mmap_read_lock(mm);
+	for_each_vma(vmi, vma) {
+		size += kobjsize(vma);
+		region = vma->vm_region;
+		if (region) {
+			size += kobjsize(region);
+			size += region->vm_end - region->vm_start;
+		}
+	}
+
+	*text = (PAGE_ALIGN(mm->end_code) - (mm->start_code & PAGE_MASK))
+		>> PAGE_SHIFT;
+	*data = (PAGE_ALIGN(mm->start_stack) - (mm->start_data & PAGE_MASK))
+		>> PAGE_SHIFT;
+	mmap_read_unlock(mm);
+	size >>= PAGE_SHIFT;
+	size += *text + *data;
+	*resident = size;
+	return size;
+}
+
+static int is_stack(struct vm_area_struct *vma)
+{
+	struct mm_struct *mm = vma->vm_mm;
+
+	/*
+	 * We make no effort to guess what a given thread considers to be
+	 * its "stack".  It's not even well-defined for programs written
+	 * languages like Go.
+	 */
+	return vma->vm_start <= mm->start_stack &&
+		vma->vm_end >= mm->start_stack;
+}
+
+/*
+ * display a single VMA to a sequenced file
+ */
+static int nommu_vma_show(struct seq_file *m, struct vm_area_struct *vma)
+{
+	struct mm_struct *mm = vma->vm_mm;
+	unsigned long ino = 0;
+	struct file *file;
+	dev_t dev = 0;
+	int flags;
+	unsigned long long pgoff = 0;
+
+	flags = vma->vm_flags;
+	file = vma->vm_file;
+
+	if (file) {
+		struct inode *inode = file_inode(vma->vm_file);
+		dev = inode->i_sb->s_dev;
+		ino = inode->i_ino;
+		pgoff = (loff_t)vma->vm_pgoff << PAGE_SHIFT;
+	}
+
+	seq_setwidth(m, 25 + sizeof(void *) * 6 - 1);
+	seq_printf(m,
+		   "%08lx-%08lx %c%c%c%c %08llx %02x:%02x %lu ",
+		   vma->vm_start,
+		   vma->vm_end,
+		   flags & VM_READ ? 'r' : '-',
+		   flags & VM_WRITE ? 'w' : '-',
+		   flags & VM_EXEC ? 'x' : '-',
+		   flags & VM_MAYSHARE ? flags & VM_SHARED ? 'S' : 's' : 'p',
+		   pgoff,
+		   MAJOR(dev), MINOR(dev), ino);
+
+	if (file) {
+		seq_pad(m, ' ');
+		seq_file_path(m, file, "");
+	} else if (mm && is_stack(vma)) {
+		seq_pad(m, ' ');
+		seq_puts(m, "[stack]");
+	}
+
+	seq_putc(m, '\n');
+	return 0;
+}
+
+/*
+ * display mapping lines for a particular process's /proc/pid/maps
+ */
+static int show_map(struct seq_file *m, void *_p)
+{
+	return nommu_vma_show(m, _p);
+}
+
+static struct vm_area_struct *proc_get_vma(struct proc_maps_private *priv,
+						loff_t *ppos)
+{
+	struct vm_area_struct *vma = vma_next(&priv->iter);
+
+	if (vma) {
+		*ppos = vma->vm_start;
+	} else {
+		*ppos = -1UL;
+	}
+
+	return vma;
+}
+
+static void *m_start(struct seq_file *m, loff_t *ppos)
+{
+	struct proc_maps_private *priv = m->private;
+	unsigned long last_addr = *ppos;
+	struct mm_struct *mm;
+
+	/* See proc_get_vma(). Zero at the start or after lseek. */
+	if (last_addr == -1UL)
+		return NULL;
+
+	/* pin the task and mm whilst we play with them */
+	priv->task = get_proc_task(priv->inode);
+	if (!priv->task)
+		return ERR_PTR(-ESRCH);
+
+	mm = priv->mm;
+	if (!mm || !mmget_not_zero(mm)) {
+		put_task_struct(priv->task);
+		priv->task = NULL;
+		return NULL;
+	}
+
+	if (mmap_read_lock_killable(mm)) {
+		mmput(mm);
+		put_task_struct(priv->task);
+		priv->task = NULL;
+		return ERR_PTR(-EINTR);
+	}
+
+	vma_iter_init(&priv->iter, mm, last_addr);
+
+	return proc_get_vma(priv, ppos);
+}
+
+static void m_stop(struct seq_file *m, void *v)
+{
+	struct proc_maps_private *priv = m->private;
+	struct mm_struct *mm = priv->mm;
+
+	if (!priv->task)
+		return;
+
+	mmap_read_unlock(mm);
+	mmput(mm);
+	put_task_struct(priv->task);
+	priv->task = NULL;
+}
+
+static void *m_next(struct seq_file *m, void *_p, loff_t *ppos)
+{
+	return proc_get_vma(m->private, ppos);
+}
+
+static const struct seq_operations proc_pid_maps_ops = {
+	.start	= m_start,
+	.next	= m_next,
+	.stop	= m_stop,
+	.show	= show_map
+};
+
+static int maps_open(struct inode *inode, struct file *file,
+		     const struct seq_operations *ops)
+{
+	struct proc_maps_private *priv;
+
+	priv = __seq_open_private(file, ops, sizeof(*priv));
+	if (!priv)
+		return -ENOMEM;
+
+	priv->inode = inode;
+	priv->mm = proc_mem_open(inode, PTRACE_MODE_READ);
+	if (IS_ERR(priv->mm)) {
+		int err = PTR_ERR(priv->mm);
+
+		seq_release_private(inode, file);
+		return err;
+	}
+
+	return 0;
+}
+
+
+static int map_release(struct inode *inode, struct file *file)
+{
+	struct seq_file *seq = file->private_data;
+	struct proc_maps_private *priv = seq->private;
+
+	if (priv->mm)
+		mmdrop(priv->mm);
+
+	return seq_release_private(inode, file);
+}
+
+static int pid_maps_open(struct inode *inode, struct file *file)
+{
+	return maps_open(inode, file, &proc_pid_maps_ops);
+}
+
+const struct file_operations proc_pid_maps_operations = {
+	.open		= pid_maps_open,
+	.read		= seq_read,
+	.llseek		= seq_lseek,
+	.release	= map_release,
+};
+
diff --git a/fs/proc/thread_self.c b/fs/proc/thread_self.c
new file mode 100644
index 000000000..a553273fb
--- /dev/null
+++ b/fs/proc/thread_self.c
@@ -0,0 +1,73 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/cache.h>
+#include <linux/sched.h>
+#include <linux/slab.h>
+#include <linux/pid_namespace.h>
+#include "internal.h"
+
+/*
+ * /proc/thread_self:
+ */
+static const char *proc_thread_self_get_link(struct dentry *dentry,
+					     struct inode *inode,
+					     struct delayed_call *done)
+{
+	struct pid_namespace *ns = proc_pid_ns(inode->i_sb);
+	pid_t tgid = task_tgid_nr_ns(current, ns);
+	pid_t pid = task_pid_nr_ns(current, ns);
+	char *name;
+
+	if (!pid)
+		return ERR_PTR(-ENOENT);
+	name = kmalloc(10 + 6 + 10 + 1, dentry ? GFP_KERNEL : GFP_ATOMIC);
+	if (unlikely(!name))
+		return dentry ? ERR_PTR(-ENOMEM) : ERR_PTR(-ECHILD);
+	sprintf(name, "%u/task/%u", tgid, pid);
+	set_delayed_call(done, kfree_link, name);
+	return name;
+}
+
+static const struct inode_operations proc_thread_self_inode_operations = {
+	.get_link	= proc_thread_self_get_link,
+};
+
+static unsigned thread_self_inum __ro_after_init;
+
+int proc_setup_thread_self(struct super_block *s)
+{
+	struct inode *root_inode = d_inode(s->s_root);
+	struct proc_fs_info *fs_info = proc_sb_info(s);
+	struct dentry *thread_self;
+	int ret = -ENOMEM;
+
+	inode_lock(root_inode);
+	thread_self = d_alloc_name(s->s_root, "thread-self");
+	if (thread_self) {
+		struct inode *inode = new_inode(s);
+		if (inode) {
+			inode->i_ino = thread_self_inum;
+			inode->i_mtime = inode->i_atime = inode->i_ctime = current_time(inode);
+			inode->i_mode = S_IFLNK | S_IRWXUGO;
+			inode->i_uid = GLOBAL_ROOT_UID;
+			inode->i_gid = GLOBAL_ROOT_GID;
+			inode->i_op = &proc_thread_self_inode_operations;
+			d_add(thread_self, inode);
+			ret = 0;
+		} else {
+			dput(thread_self);
+		}
+	}
+	inode_unlock(root_inode);
+
+	if (ret)
+		pr_err("proc_fill_super: can't allocate /proc/thread-self\n");
+	else
+		fs_info->proc_thread_self = thread_self;
+
+	return ret;
+}
+
+void __init proc_thread_self_init(void)
+{
+	proc_alloc_inum(&thread_self_inum);
+}
diff --git a/fs/proc/uptime.c b/fs/proc/uptime.c
new file mode 100644
index 000000000..b5343d209
--- /dev/null
+++ b/fs/proc/uptime.c
@@ -0,0 +1,49 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/fs.h>
+#include <linux/init.h>
+#include <linux/proc_fs.h>
+#include <linux/sched.h>
+#include <linux/seq_file.h>
+#include <linux/time.h>
+#include <linux/time_namespace.h>
+#include <linux/kernel_stat.h>
+#include "internal.h"
+
+static int uptime_proc_show(struct seq_file *m, void *v)
+{
+	struct timespec64 uptime;
+	struct timespec64 idle;
+	u64 idle_nsec;
+	u32 rem;
+	int i;
+
+	idle_nsec = 0;
+	for_each_possible_cpu(i) {
+		struct kernel_cpustat kcs;
+
+		kcpustat_cpu_fetch(&kcs, i);
+		idle_nsec += get_idle_time(&kcs, i);
+	}
+
+	ktime_get_boottime_ts64(&uptime);
+	timens_add_boottime(&uptime);
+
+	idle.tv_sec = div_u64_rem(idle_nsec, NSEC_PER_SEC, &rem);
+	idle.tv_nsec = rem;
+	seq_printf(m, "%lu.%02lu %lu.%02lu\n",
+			(unsigned long) uptime.tv_sec,
+			(uptime.tv_nsec / (NSEC_PER_SEC / 100)),
+			(unsigned long) idle.tv_sec,
+			(idle.tv_nsec / (NSEC_PER_SEC / 100)));
+	return 0;
+}
+
+static int __init proc_uptime_init(void)
+{
+	struct proc_dir_entry *pde;
+
+	pde = proc_create_single("uptime", 0, NULL, uptime_proc_show);
+	pde_make_permanent(pde);
+	return 0;
+}
+fs_initcall(proc_uptime_init);
diff --git a/fs/proc/util.c b/fs/proc/util.c
new file mode 100644
index 000000000..98f8adc17
--- /dev/null
+++ b/fs/proc/util.c
@@ -0,0 +1,24 @@
+#include <linux/dcache.h>
+#include "internal.h"
+
+unsigned name_to_int(const struct qstr *qstr)
+{
+	const char *name = qstr->name;
+	int len = qstr->len;
+	unsigned n = 0;
+
+	if (len > 1 && *name == '0')
+		goto out;
+	do {
+		unsigned c = *name++ - '0';
+		if (c > 9)
+			goto out;
+		if (n >= (~0U-9)/10)
+			goto out;
+		n *= 10;
+		n += c;
+	} while (--len > 0);
+	return n;
+out:
+	return ~0U;
+}
diff --git a/fs/proc/version.c b/fs/proc/version.c
new file mode 100644
index 000000000..02e3c3cd4
--- /dev/null
+++ b/fs/proc/version.c
@@ -0,0 +1,27 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/fs.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/proc_fs.h>
+#include <linux/seq_file.h>
+#include <linux/utsname.h>
+#include "internal.h"
+
+static int version_proc_show(struct seq_file *m, void *v)
+{
+	seq_printf(m, linux_proc_banner,
+		utsname()->sysname,
+		utsname()->release,
+		utsname()->version);
+	return 0;
+}
+
+static int __init proc_version_init(void)
+{
+	struct proc_dir_entry *pde;
+
+	pde = proc_create_single("version", 0, NULL, version_proc_show);
+	pde_make_permanent(pde);
+	return 0;
+}
+fs_initcall(proc_version_init);
diff --git a/fs/proc/vmcore.c b/fs/proc/vmcore.c
new file mode 100644
index 000000000..1ec0647a2
--- /dev/null
+++ b/fs/proc/vmcore.c
@@ -0,0 +1,1603 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ *	fs/proc/vmcore.c Interface for accessing the crash
+ * 				 dump from the system's previous life.
+ * 	Heavily borrowed from fs/proc/kcore.c
+ *	Created by: Hariprasad Nellitheertha (hari@in.ibm.com)
+ *	Copyright (C) IBM Corporation, 2004. All rights reserved
+ *
+ */
+
+#include <linux/mm.h>
+#include <linux/kcore.h>
+#include <linux/user.h>
+#include <linux/elf.h>
+#include <linux/elfcore.h>
+#include <linux/export.h>
+#include <linux/slab.h>
+#include <linux/highmem.h>
+#include <linux/printk.h>
+#include <linux/memblock.h>
+#include <linux/init.h>
+#include <linux/crash_dump.h>
+#include <linux/list.h>
+#include <linux/moduleparam.h>
+#include <linux/mutex.h>
+#include <linux/vmalloc.h>
+#include <linux/pagemap.h>
+#include <linux/uio.h>
+#include <linux/cc_platform.h>
+#include <asm/io.h>
+#include "internal.h"
+
+/* List representing chunks of contiguous memory areas and their offsets in
+ * vmcore file.
+ */
+static LIST_HEAD(vmcore_list);
+
+/* Stores the pointer to the buffer containing kernel elf core headers. */
+static char *elfcorebuf;
+static size_t elfcorebuf_sz;
+static size_t elfcorebuf_sz_orig;
+
+static char *elfnotes_buf;
+static size_t elfnotes_sz;
+/* Size of all notes minus the device dump notes */
+static size_t elfnotes_orig_sz;
+
+/* Total size of vmcore file. */
+static u64 vmcore_size;
+
+static struct proc_dir_entry *proc_vmcore;
+
+#ifdef CONFIG_PROC_VMCORE_DEVICE_DUMP
+/* Device Dump list and mutex to synchronize access to list */
+static LIST_HEAD(vmcoredd_list);
+static DEFINE_MUTEX(vmcoredd_mutex);
+
+static bool vmcoredd_disabled;
+core_param(novmcoredd, vmcoredd_disabled, bool, 0);
+#endif /* CONFIG_PROC_VMCORE_DEVICE_DUMP */
+
+/* Device Dump Size */
+static size_t vmcoredd_orig_sz;
+
+static DEFINE_SPINLOCK(vmcore_cb_lock);
+DEFINE_STATIC_SRCU(vmcore_cb_srcu);
+/* List of registered vmcore callbacks. */
+static LIST_HEAD(vmcore_cb_list);
+/* Whether the vmcore has been opened once. */
+static bool vmcore_opened;
+
+void register_vmcore_cb(struct vmcore_cb *cb)
+{
+	INIT_LIST_HEAD(&cb->next);
+	spin_lock(&vmcore_cb_lock);
+	list_add_tail(&cb->next, &vmcore_cb_list);
+	/*
+	 * Registering a vmcore callback after the vmcore was opened is
+	 * very unusual (e.g., manual driver loading).
+	 */
+	if (vmcore_opened)
+		pr_warn_once("Unexpected vmcore callback registration\n");
+	spin_unlock(&vmcore_cb_lock);
+}
+EXPORT_SYMBOL_GPL(register_vmcore_cb);
+
+void unregister_vmcore_cb(struct vmcore_cb *cb)
+{
+	spin_lock(&vmcore_cb_lock);
+	list_del_rcu(&cb->next);
+	/*
+	 * Unregistering a vmcore callback after the vmcore was opened is
+	 * very unusual (e.g., forced driver removal), but we cannot stop
+	 * unregistering.
+	 */
+	if (vmcore_opened)
+		pr_warn_once("Unexpected vmcore callback unregistration\n");
+	spin_unlock(&vmcore_cb_lock);
+
+	synchronize_srcu(&vmcore_cb_srcu);
+}
+EXPORT_SYMBOL_GPL(unregister_vmcore_cb);
+
+static bool pfn_is_ram(unsigned long pfn)
+{
+	struct vmcore_cb *cb;
+	bool ret = true;
+
+	list_for_each_entry_srcu(cb, &vmcore_cb_list, next,
+				 srcu_read_lock_held(&vmcore_cb_srcu)) {
+		if (unlikely(!cb->pfn_is_ram))
+			continue;
+		ret = cb->pfn_is_ram(cb, pfn);
+		if (!ret)
+			break;
+	}
+
+	return ret;
+}
+
+static int open_vmcore(struct inode *inode, struct file *file)
+{
+	spin_lock(&vmcore_cb_lock);
+	vmcore_opened = true;
+	spin_unlock(&vmcore_cb_lock);
+
+	return 0;
+}
+
+/* Reads a page from the oldmem device from given offset. */
+ssize_t read_from_oldmem(struct iov_iter *iter, size_t count,
+			 u64 *ppos, bool encrypted)
+{
+	unsigned long pfn, offset;
+	ssize_t nr_bytes;
+	ssize_t read = 0, tmp;
+	int idx;
+
+	if (!count)
+		return 0;
+
+	offset = (unsigned long)(*ppos % PAGE_SIZE);
+	pfn = (unsigned long)(*ppos / PAGE_SIZE);
+
+	idx = srcu_read_lock(&vmcore_cb_srcu);
+	do {
+		if (count > (PAGE_SIZE - offset))
+			nr_bytes = PAGE_SIZE - offset;
+		else
+			nr_bytes = count;
+
+		/* If pfn is not ram, return zeros for sparse dump files */
+		if (!pfn_is_ram(pfn)) {
+			tmp = iov_iter_zero(nr_bytes, iter);
+		} else {
+			if (encrypted)
+				tmp = copy_oldmem_page_encrypted(iter, pfn,
+								 nr_bytes,
+								 offset);
+			else
+				tmp = copy_oldmem_page(iter, pfn, nr_bytes,
+						       offset);
+		}
+		if (tmp < nr_bytes) {
+			srcu_read_unlock(&vmcore_cb_srcu, idx);
+			return -EFAULT;
+		}
+
+		*ppos += nr_bytes;
+		count -= nr_bytes;
+		read += nr_bytes;
+		++pfn;
+		offset = 0;
+	} while (count);
+	srcu_read_unlock(&vmcore_cb_srcu, idx);
+
+	return read;
+}
+
+/*
+ * Architectures may override this function to allocate ELF header in 2nd kernel
+ */
+int __weak elfcorehdr_alloc(unsigned long long *addr, unsigned long long *size)
+{
+	return 0;
+}
+
+/*
+ * Architectures may override this function to free header
+ */
+void __weak elfcorehdr_free(unsigned long long addr)
+{}
+
+/*
+ * Architectures may override this function to read from ELF header
+ */
+ssize_t __weak elfcorehdr_read(char *buf, size_t count, u64 *ppos)
+{
+	struct kvec kvec = { .iov_base = buf, .iov_len = count };
+	struct iov_iter iter;
+
+	iov_iter_kvec(&iter, ITER_DEST, &kvec, 1, count);
+
+	return read_from_oldmem(&iter, count, ppos, false);
+}
+
+/*
+ * Architectures may override this function to read from notes sections
+ */
+ssize_t __weak elfcorehdr_read_notes(char *buf, size_t count, u64 *ppos)
+{
+	struct kvec kvec = { .iov_base = buf, .iov_len = count };
+	struct iov_iter iter;
+
+	iov_iter_kvec(&iter, ITER_DEST, &kvec, 1, count);
+
+	return read_from_oldmem(&iter, count, ppos,
+			cc_platform_has(CC_ATTR_MEM_ENCRYPT));
+}
+
+/*
+ * Architectures may override this function to map oldmem
+ */
+int __weak remap_oldmem_pfn_range(struct vm_area_struct *vma,
+				  unsigned long from, unsigned long pfn,
+				  unsigned long size, pgprot_t prot)
+{
+	prot = pgprot_encrypted(prot);
+	return remap_pfn_range(vma, from, pfn, size, prot);
+}
+
+/*
+ * Architectures which support memory encryption override this.
+ */
+ssize_t __weak copy_oldmem_page_encrypted(struct iov_iter *iter,
+		unsigned long pfn, size_t csize, unsigned long offset)
+{
+	return copy_oldmem_page(iter, pfn, csize, offset);
+}
+
+#ifdef CONFIG_PROC_VMCORE_DEVICE_DUMP
+static int vmcoredd_copy_dumps(struct iov_iter *iter, u64 start, size_t size)
+{
+	struct vmcoredd_node *dump;
+	u64 offset = 0;
+	int ret = 0;
+	size_t tsz;
+	char *buf;
+
+	mutex_lock(&vmcoredd_mutex);
+	list_for_each_entry(dump, &vmcoredd_list, list) {
+		if (start < offset + dump->size) {
+			tsz = min(offset + (u64)dump->size - start, (u64)size);
+			buf = dump->buf + start - offset;
+			if (copy_to_iter(buf, tsz, iter) < tsz) {
+				ret = -EFAULT;
+				goto out_unlock;
+			}
+
+			size -= tsz;
+			start += tsz;
+
+			/* Leave now if buffer filled already */
+			if (!size)
+				goto out_unlock;
+		}
+		offset += dump->size;
+	}
+
+out_unlock:
+	mutex_unlock(&vmcoredd_mutex);
+	return ret;
+}
+
+#ifdef CONFIG_MMU
+static int vmcoredd_mmap_dumps(struct vm_area_struct *vma, unsigned long dst,
+			       u64 start, size_t size)
+{
+	struct vmcoredd_node *dump;
+	u64 offset = 0;
+	int ret = 0;
+	size_t tsz;
+	char *buf;
+
+	mutex_lock(&vmcoredd_mutex);
+	list_for_each_entry(dump, &vmcoredd_list, list) {
+		if (start < offset + dump->size) {
+			tsz = min(offset + (u64)dump->size - start, (u64)size);
+			buf = dump->buf + start - offset;
+			if (remap_vmalloc_range_partial(vma, dst, buf, 0,
+							tsz)) {
+				ret = -EFAULT;
+				goto out_unlock;
+			}
+
+			size -= tsz;
+			start += tsz;
+			dst += tsz;
+
+			/* Leave now if buffer filled already */
+			if (!size)
+				goto out_unlock;
+		}
+		offset += dump->size;
+	}
+
+out_unlock:
+	mutex_unlock(&vmcoredd_mutex);
+	return ret;
+}
+#endif /* CONFIG_MMU */
+#endif /* CONFIG_PROC_VMCORE_DEVICE_DUMP */
+
+/* Read from the ELF header and then the crash dump. On error, negative value is
+ * returned otherwise number of bytes read are returned.
+ */
+static ssize_t __read_vmcore(struct iov_iter *iter, loff_t *fpos)
+{
+	ssize_t acc = 0, tmp;
+	size_t tsz;
+	u64 start;
+	struct vmcore *m = NULL;
+
+	if (!iov_iter_count(iter) || *fpos >= vmcore_size)
+		return 0;
+
+	iov_iter_truncate(iter, vmcore_size - *fpos);
+
+	/* Read ELF core header */
+	if (*fpos < elfcorebuf_sz) {
+		tsz = min(elfcorebuf_sz - (size_t)*fpos, iov_iter_count(iter));
+		if (copy_to_iter(elfcorebuf + *fpos, tsz, iter) < tsz)
+			return -EFAULT;
+		*fpos += tsz;
+		acc += tsz;
+
+		/* leave now if filled buffer already */
+		if (!iov_iter_count(iter))
+			return acc;
+	}
+
+	/* Read Elf note segment */
+	if (*fpos < elfcorebuf_sz + elfnotes_sz) {
+		void *kaddr;
+
+		/* We add device dumps before other elf notes because the
+		 * other elf notes may not fill the elf notes buffer
+		 * completely and we will end up with zero-filled data
+		 * between the elf notes and the device dumps. Tools will
+		 * then try to decode this zero-filled data as valid notes
+		 * and we don't want that. Hence, adding device dumps before
+		 * the other elf notes ensure that zero-filled data can be
+		 * avoided.
+		 */
+#ifdef CONFIG_PROC_VMCORE_DEVICE_DUMP
+		/* Read device dumps */
+		if (*fpos < elfcorebuf_sz + vmcoredd_orig_sz) {
+			tsz = min(elfcorebuf_sz + vmcoredd_orig_sz -
+				  (size_t)*fpos, iov_iter_count(iter));
+			start = *fpos - elfcorebuf_sz;
+			if (vmcoredd_copy_dumps(iter, start, tsz))
+				return -EFAULT;
+
+			*fpos += tsz;
+			acc += tsz;
+
+			/* leave now if filled buffer already */
+			if (!iov_iter_count(iter))
+				return acc;
+		}
+#endif /* CONFIG_PROC_VMCORE_DEVICE_DUMP */
+
+		/* Read remaining elf notes */
+		tsz = min(elfcorebuf_sz + elfnotes_sz - (size_t)*fpos,
+			  iov_iter_count(iter));
+		kaddr = elfnotes_buf + *fpos - elfcorebuf_sz - vmcoredd_orig_sz;
+		if (copy_to_iter(kaddr, tsz, iter) < tsz)
+			return -EFAULT;
+
+		*fpos += tsz;
+		acc += tsz;
+
+		/* leave now if filled buffer already */
+		if (!iov_iter_count(iter))
+			return acc;
+	}
+
+	list_for_each_entry(m, &vmcore_list, list) {
+		if (*fpos < m->offset + m->size) {
+			tsz = (size_t)min_t(unsigned long long,
+					    m->offset + m->size - *fpos,
+					    iov_iter_count(iter));
+			start = m->paddr + *fpos - m->offset;
+			tmp = read_from_oldmem(iter, tsz, &start,
+					cc_platform_has(CC_ATTR_MEM_ENCRYPT));
+			if (tmp < 0)
+				return tmp;
+			*fpos += tsz;
+			acc += tsz;
+
+			/* leave now if filled buffer already */
+			if (!iov_iter_count(iter))
+				return acc;
+		}
+	}
+
+	return acc;
+}
+
+static ssize_t read_vmcore(struct kiocb *iocb, struct iov_iter *iter)
+{
+	return __read_vmcore(iter, &iocb->ki_pos);
+}
+
+/*
+ * The vmcore fault handler uses the page cache and fills data using the
+ * standard __read_vmcore() function.
+ *
+ * On s390 the fault handler is used for memory regions that can't be mapped
+ * directly with remap_pfn_range().
+ */
+static vm_fault_t mmap_vmcore_fault(struct vm_fault *vmf)
+{
+#ifdef CONFIG_S390
+	struct address_space *mapping = vmf->vma->vm_file->f_mapping;
+	pgoff_t index = vmf->pgoff;
+	struct iov_iter iter;
+	struct kvec kvec;
+	struct page *page;
+	loff_t offset;
+	int rc;
+
+	page = find_or_create_page(mapping, index, GFP_KERNEL);
+	if (!page)
+		return VM_FAULT_OOM;
+	if (!PageUptodate(page)) {
+		offset = (loff_t) index << PAGE_SHIFT;
+		kvec.iov_base = page_address(page);
+		kvec.iov_len = PAGE_SIZE;
+		iov_iter_kvec(&iter, ITER_DEST, &kvec, 1, PAGE_SIZE);
+
+		rc = __read_vmcore(&iter, &offset);
+		if (rc < 0) {
+			unlock_page(page);
+			put_page(page);
+			return vmf_error(rc);
+		}
+		SetPageUptodate(page);
+	}
+	unlock_page(page);
+	vmf->page = page;
+	return 0;
+#else
+	return VM_FAULT_SIGBUS;
+#endif
+}
+
+static const struct vm_operations_struct vmcore_mmap_ops = {
+	.fault = mmap_vmcore_fault,
+};
+
+/**
+ * vmcore_alloc_buf - allocate buffer in vmalloc memory
+ * @size: size of buffer
+ *
+ * If CONFIG_MMU is defined, use vmalloc_user() to allow users to mmap
+ * the buffer to user-space by means of remap_vmalloc_range().
+ *
+ * If CONFIG_MMU is not defined, use vzalloc() since mmap_vmcore() is
+ * disabled and there's no need to allow users to mmap the buffer.
+ */
+static inline char *vmcore_alloc_buf(size_t size)
+{
+#ifdef CONFIG_MMU
+	return vmalloc_user(size);
+#else
+	return vzalloc(size);
+#endif
+}
+
+/*
+ * Disable mmap_vmcore() if CONFIG_MMU is not defined. MMU is
+ * essential for mmap_vmcore() in order to map physically
+ * non-contiguous objects (ELF header, ELF note segment and memory
+ * regions in the 1st kernel pointed to by PT_LOAD entries) into
+ * virtually contiguous user-space in ELF layout.
+ */
+#ifdef CONFIG_MMU
+/*
+ * remap_oldmem_pfn_checked - do remap_oldmem_pfn_range replacing all pages
+ * reported as not being ram with the zero page.
+ *
+ * @vma: vm_area_struct describing requested mapping
+ * @from: start remapping from
+ * @pfn: page frame number to start remapping to
+ * @size: remapping size
+ * @prot: protection bits
+ *
+ * Returns zero on success, -EAGAIN on failure.
+ */
+static int remap_oldmem_pfn_checked(struct vm_area_struct *vma,
+				    unsigned long from, unsigned long pfn,
+				    unsigned long size, pgprot_t prot)
+{
+	unsigned long map_size;
+	unsigned long pos_start, pos_end, pos;
+	unsigned long zeropage_pfn = my_zero_pfn(0);
+	size_t len = 0;
+
+	pos_start = pfn;
+	pos_end = pfn + (size >> PAGE_SHIFT);
+
+	for (pos = pos_start; pos < pos_end; ++pos) {
+		if (!pfn_is_ram(pos)) {
+			/*
+			 * We hit a page which is not ram. Remap the continuous
+			 * region between pos_start and pos-1 and replace
+			 * the non-ram page at pos with the zero page.
+			 */
+			if (pos > pos_start) {
+				/* Remap continuous region */
+				map_size = (pos - pos_start) << PAGE_SHIFT;
+				if (remap_oldmem_pfn_range(vma, from + len,
+							   pos_start, map_size,
+							   prot))
+					goto fail;
+				len += map_size;
+			}
+			/* Remap the zero page */
+			if (remap_oldmem_pfn_range(vma, from + len,
+						   zeropage_pfn,
+						   PAGE_SIZE, prot))
+				goto fail;
+			len += PAGE_SIZE;
+			pos_start = pos + 1;
+		}
+	}
+	if (pos > pos_start) {
+		/* Remap the rest */
+		map_size = (pos - pos_start) << PAGE_SHIFT;
+		if (remap_oldmem_pfn_range(vma, from + len, pos_start,
+					   map_size, prot))
+			goto fail;
+	}
+	return 0;
+fail:
+	do_munmap(vma->vm_mm, from, len, NULL);
+	return -EAGAIN;
+}
+
+static int vmcore_remap_oldmem_pfn(struct vm_area_struct *vma,
+			    unsigned long from, unsigned long pfn,
+			    unsigned long size, pgprot_t prot)
+{
+	int ret, idx;
+
+	/*
+	 * Check if a callback was registered to avoid looping over all
+	 * pages without a reason.
+	 */
+	idx = srcu_read_lock(&vmcore_cb_srcu);
+	if (!list_empty(&vmcore_cb_list))
+		ret = remap_oldmem_pfn_checked(vma, from, pfn, size, prot);
+	else
+		ret = remap_oldmem_pfn_range(vma, from, pfn, size, prot);
+	srcu_read_unlock(&vmcore_cb_srcu, idx);
+	return ret;
+}
+
+static int mmap_vmcore(struct file *file, struct vm_area_struct *vma)
+{
+	size_t size = vma->vm_end - vma->vm_start;
+	u64 start, end, len, tsz;
+	struct vmcore *m;
+
+	start = (u64)vma->vm_pgoff << PAGE_SHIFT;
+	end = start + size;
+
+	if (size > vmcore_size || end > vmcore_size)
+		return -EINVAL;
+
+	if (vma->vm_flags & (VM_WRITE | VM_EXEC))
+		return -EPERM;
+
+	vma->vm_flags &= ~(VM_MAYWRITE | VM_MAYEXEC);
+	vma->vm_flags |= VM_MIXEDMAP;
+	vma->vm_ops = &vmcore_mmap_ops;
+
+	len = 0;
+
+	if (start < elfcorebuf_sz) {
+		u64 pfn;
+
+		tsz = min(elfcorebuf_sz - (size_t)start, size);
+		pfn = __pa(elfcorebuf + start) >> PAGE_SHIFT;
+		if (remap_pfn_range(vma, vma->vm_start, pfn, tsz,
+				    vma->vm_page_prot))
+			return -EAGAIN;
+		size -= tsz;
+		start += tsz;
+		len += tsz;
+
+		if (size == 0)
+			return 0;
+	}
+
+	if (start < elfcorebuf_sz + elfnotes_sz) {
+		void *kaddr;
+
+		/* We add device dumps before other elf notes because the
+		 * other elf notes may not fill the elf notes buffer
+		 * completely and we will end up with zero-filled data
+		 * between the elf notes and the device dumps. Tools will
+		 * then try to decode this zero-filled data as valid notes
+		 * and we don't want that. Hence, adding device dumps before
+		 * the other elf notes ensure that zero-filled data can be
+		 * avoided. This also ensures that the device dumps and
+		 * other elf notes can be properly mmaped at page aligned
+		 * address.
+		 */
+#ifdef CONFIG_PROC_VMCORE_DEVICE_DUMP
+		/* Read device dumps */
+		if (start < elfcorebuf_sz + vmcoredd_orig_sz) {
+			u64 start_off;
+
+			tsz = min(elfcorebuf_sz + vmcoredd_orig_sz -
+				  (size_t)start, size);
+			start_off = start - elfcorebuf_sz;
+			if (vmcoredd_mmap_dumps(vma, vma->vm_start + len,
+						start_off, tsz))
+				goto fail;
+
+			size -= tsz;
+			start += tsz;
+			len += tsz;
+
+			/* leave now if filled buffer already */
+			if (!size)
+				return 0;
+		}
+#endif /* CONFIG_PROC_VMCORE_DEVICE_DUMP */
+
+		/* Read remaining elf notes */
+		tsz = min(elfcorebuf_sz + elfnotes_sz - (size_t)start, size);
+		kaddr = elfnotes_buf + start - elfcorebuf_sz - vmcoredd_orig_sz;
+		if (remap_vmalloc_range_partial(vma, vma->vm_start + len,
+						kaddr, 0, tsz))
+			goto fail;
+
+		size -= tsz;
+		start += tsz;
+		len += tsz;
+
+		if (size == 0)
+			return 0;
+	}
+
+	list_for_each_entry(m, &vmcore_list, list) {
+		if (start < m->offset + m->size) {
+			u64 paddr = 0;
+
+			tsz = (size_t)min_t(unsigned long long,
+					    m->offset + m->size - start, size);
+			paddr = m->paddr + start - m->offset;
+			if (vmcore_remap_oldmem_pfn(vma, vma->vm_start + len,
+						    paddr >> PAGE_SHIFT, tsz,
+						    vma->vm_page_prot))
+				goto fail;
+			size -= tsz;
+			start += tsz;
+			len += tsz;
+
+			if (size == 0)
+				return 0;
+		}
+	}
+
+	return 0;
+fail:
+	do_munmap(vma->vm_mm, vma->vm_start, len, NULL);
+	return -EAGAIN;
+}
+#else
+static int mmap_vmcore(struct file *file, struct vm_area_struct *vma)
+{
+	return -ENOSYS;
+}
+#endif
+
+static const struct proc_ops vmcore_proc_ops = {
+	.proc_open	= open_vmcore,
+	.proc_read_iter	= read_vmcore,
+	.proc_lseek	= default_llseek,
+	.proc_mmap	= mmap_vmcore,
+};
+
+static struct vmcore* __init get_new_element(void)
+{
+	return kzalloc(sizeof(struct vmcore), GFP_KERNEL);
+}
+
+static u64 get_vmcore_size(size_t elfsz, size_t elfnotesegsz,
+			   struct list_head *vc_list)
+{
+	u64 size;
+	struct vmcore *m;
+
+	size = elfsz + elfnotesegsz;
+	list_for_each_entry(m, vc_list, list) {
+		size += m->size;
+	}
+	return size;
+}
+
+/**
+ * update_note_header_size_elf64 - update p_memsz member of each PT_NOTE entry
+ *
+ * @ehdr_ptr: ELF header
+ *
+ * This function updates p_memsz member of each PT_NOTE entry in the
+ * program header table pointed to by @ehdr_ptr to real size of ELF
+ * note segment.
+ */
+static int __init update_note_header_size_elf64(const Elf64_Ehdr *ehdr_ptr)
+{
+	int i, rc=0;
+	Elf64_Phdr *phdr_ptr;
+	Elf64_Nhdr *nhdr_ptr;
+
+	phdr_ptr = (Elf64_Phdr *)(ehdr_ptr + 1);
+	for (i = 0; i < ehdr_ptr->e_phnum; i++, phdr_ptr++) {
+		void *notes_section;
+		u64 offset, max_sz, sz, real_sz = 0;
+		if (phdr_ptr->p_type != PT_NOTE)
+			continue;
+		max_sz = phdr_ptr->p_memsz;
+		offset = phdr_ptr->p_offset;
+		notes_section = kmalloc(max_sz, GFP_KERNEL);
+		if (!notes_section)
+			return -ENOMEM;
+		rc = elfcorehdr_read_notes(notes_section, max_sz, &offset);
+		if (rc < 0) {
+			kfree(notes_section);
+			return rc;
+		}
+		nhdr_ptr = notes_section;
+		while (nhdr_ptr->n_namesz != 0) {
+			sz = sizeof(Elf64_Nhdr) +
+				(((u64)nhdr_ptr->n_namesz + 3) & ~3) +
+				(((u64)nhdr_ptr->n_descsz + 3) & ~3);
+			if ((real_sz + sz) > max_sz) {
+				pr_warn("Warning: Exceeded p_memsz, dropping PT_NOTE entry n_namesz=0x%x, n_descsz=0x%x\n",
+					nhdr_ptr->n_namesz, nhdr_ptr->n_descsz);
+				break;
+			}
+			real_sz += sz;
+			nhdr_ptr = (Elf64_Nhdr*)((char*)nhdr_ptr + sz);
+		}
+		kfree(notes_section);
+		phdr_ptr->p_memsz = real_sz;
+		if (real_sz == 0) {
+			pr_warn("Warning: Zero PT_NOTE entries found\n");
+		}
+	}
+
+	return 0;
+}
+
+/**
+ * get_note_number_and_size_elf64 - get the number of PT_NOTE program
+ * headers and sum of real size of their ELF note segment headers and
+ * data.
+ *
+ * @ehdr_ptr: ELF header
+ * @nr_ptnote: buffer for the number of PT_NOTE program headers
+ * @sz_ptnote: buffer for size of unique PT_NOTE program header
+ *
+ * This function is used to merge multiple PT_NOTE program headers
+ * into a unique single one. The resulting unique entry will have
+ * @sz_ptnote in its phdr->p_mem.
+ *
+ * It is assumed that program headers with PT_NOTE type pointed to by
+ * @ehdr_ptr has already been updated by update_note_header_size_elf64
+ * and each of PT_NOTE program headers has actual ELF note segment
+ * size in its p_memsz member.
+ */
+static int __init get_note_number_and_size_elf64(const Elf64_Ehdr *ehdr_ptr,
+						 int *nr_ptnote, u64 *sz_ptnote)
+{
+	int i;
+	Elf64_Phdr *phdr_ptr;
+
+	*nr_ptnote = *sz_ptnote = 0;
+
+	phdr_ptr = (Elf64_Phdr *)(ehdr_ptr + 1);
+	for (i = 0; i < ehdr_ptr->e_phnum; i++, phdr_ptr++) {
+		if (phdr_ptr->p_type != PT_NOTE)
+			continue;
+		*nr_ptnote += 1;
+		*sz_ptnote += phdr_ptr->p_memsz;
+	}
+
+	return 0;
+}
+
+/**
+ * copy_notes_elf64 - copy ELF note segments in a given buffer
+ *
+ * @ehdr_ptr: ELF header
+ * @notes_buf: buffer into which ELF note segments are copied
+ *
+ * This function is used to copy ELF note segment in the 1st kernel
+ * into the buffer @notes_buf in the 2nd kernel. It is assumed that
+ * size of the buffer @notes_buf is equal to or larger than sum of the
+ * real ELF note segment headers and data.
+ *
+ * It is assumed that program headers with PT_NOTE type pointed to by
+ * @ehdr_ptr has already been updated by update_note_header_size_elf64
+ * and each of PT_NOTE program headers has actual ELF note segment
+ * size in its p_memsz member.
+ */
+static int __init copy_notes_elf64(const Elf64_Ehdr *ehdr_ptr, char *notes_buf)
+{
+	int i, rc=0;
+	Elf64_Phdr *phdr_ptr;
+
+	phdr_ptr = (Elf64_Phdr*)(ehdr_ptr + 1);
+
+	for (i = 0; i < ehdr_ptr->e_phnum; i++, phdr_ptr++) {
+		u64 offset;
+		if (phdr_ptr->p_type != PT_NOTE)
+			continue;
+		offset = phdr_ptr->p_offset;
+		rc = elfcorehdr_read_notes(notes_buf, phdr_ptr->p_memsz,
+					   &offset);
+		if (rc < 0)
+			return rc;
+		notes_buf += phdr_ptr->p_memsz;
+	}
+
+	return 0;
+}
+
+/* Merges all the PT_NOTE headers into one. */
+static int __init merge_note_headers_elf64(char *elfptr, size_t *elfsz,
+					   char **notes_buf, size_t *notes_sz)
+{
+	int i, nr_ptnote=0, rc=0;
+	char *tmp;
+	Elf64_Ehdr *ehdr_ptr;
+	Elf64_Phdr phdr;
+	u64 phdr_sz = 0, note_off;
+
+	ehdr_ptr = (Elf64_Ehdr *)elfptr;
+
+	rc = update_note_header_size_elf64(ehdr_ptr);
+	if (rc < 0)
+		return rc;
+
+	rc = get_note_number_and_size_elf64(ehdr_ptr, &nr_ptnote, &phdr_sz);
+	if (rc < 0)
+		return rc;
+
+	*notes_sz = roundup(phdr_sz, PAGE_SIZE);
+	*notes_buf = vmcore_alloc_buf(*notes_sz);
+	if (!*notes_buf)
+		return -ENOMEM;
+
+	rc = copy_notes_elf64(ehdr_ptr, *notes_buf);
+	if (rc < 0)
+		return rc;
+
+	/* Prepare merged PT_NOTE program header. */
+	phdr.p_type    = PT_NOTE;
+	phdr.p_flags   = 0;
+	note_off = sizeof(Elf64_Ehdr) +
+			(ehdr_ptr->e_phnum - nr_ptnote +1) * sizeof(Elf64_Phdr);
+	phdr.p_offset  = roundup(note_off, PAGE_SIZE);
+	phdr.p_vaddr   = phdr.p_paddr = 0;
+	phdr.p_filesz  = phdr.p_memsz = phdr_sz;
+	phdr.p_align   = 0;
+
+	/* Add merged PT_NOTE program header*/
+	tmp = elfptr + sizeof(Elf64_Ehdr);
+	memcpy(tmp, &phdr, sizeof(phdr));
+	tmp += sizeof(phdr);
+
+	/* Remove unwanted PT_NOTE program headers. */
+	i = (nr_ptnote - 1) * sizeof(Elf64_Phdr);
+	*elfsz = *elfsz - i;
+	memmove(tmp, tmp+i, ((*elfsz)-sizeof(Elf64_Ehdr)-sizeof(Elf64_Phdr)));
+	memset(elfptr + *elfsz, 0, i);
+	*elfsz = roundup(*elfsz, PAGE_SIZE);
+
+	/* Modify e_phnum to reflect merged headers. */
+	ehdr_ptr->e_phnum = ehdr_ptr->e_phnum - nr_ptnote + 1;
+
+	/* Store the size of all notes.  We need this to update the note
+	 * header when the device dumps will be added.
+	 */
+	elfnotes_orig_sz = phdr.p_memsz;
+
+	return 0;
+}
+
+/**
+ * update_note_header_size_elf32 - update p_memsz member of each PT_NOTE entry
+ *
+ * @ehdr_ptr: ELF header
+ *
+ * This function updates p_memsz member of each PT_NOTE entry in the
+ * program header table pointed to by @ehdr_ptr to real size of ELF
+ * note segment.
+ */
+static int __init update_note_header_size_elf32(const Elf32_Ehdr *ehdr_ptr)
+{
+	int i, rc=0;
+	Elf32_Phdr *phdr_ptr;
+	Elf32_Nhdr *nhdr_ptr;
+
+	phdr_ptr = (Elf32_Phdr *)(ehdr_ptr + 1);
+	for (i = 0; i < ehdr_ptr->e_phnum; i++, phdr_ptr++) {
+		void *notes_section;
+		u64 offset, max_sz, sz, real_sz = 0;
+		if (phdr_ptr->p_type != PT_NOTE)
+			continue;
+		max_sz = phdr_ptr->p_memsz;
+		offset = phdr_ptr->p_offset;
+		notes_section = kmalloc(max_sz, GFP_KERNEL);
+		if (!notes_section)
+			return -ENOMEM;
+		rc = elfcorehdr_read_notes(notes_section, max_sz, &offset);
+		if (rc < 0) {
+			kfree(notes_section);
+			return rc;
+		}
+		nhdr_ptr = notes_section;
+		while (nhdr_ptr->n_namesz != 0) {
+			sz = sizeof(Elf32_Nhdr) +
+				(((u64)nhdr_ptr->n_namesz + 3) & ~3) +
+				(((u64)nhdr_ptr->n_descsz + 3) & ~3);
+			if ((real_sz + sz) > max_sz) {
+				pr_warn("Warning: Exceeded p_memsz, dropping PT_NOTE entry n_namesz=0x%x, n_descsz=0x%x\n",
+					nhdr_ptr->n_namesz, nhdr_ptr->n_descsz);
+				break;
+			}
+			real_sz += sz;
+			nhdr_ptr = (Elf32_Nhdr*)((char*)nhdr_ptr + sz);
+		}
+		kfree(notes_section);
+		phdr_ptr->p_memsz = real_sz;
+		if (real_sz == 0) {
+			pr_warn("Warning: Zero PT_NOTE entries found\n");
+		}
+	}
+
+	return 0;
+}
+
+/**
+ * get_note_number_and_size_elf32 - get the number of PT_NOTE program
+ * headers and sum of real size of their ELF note segment headers and
+ * data.
+ *
+ * @ehdr_ptr: ELF header
+ * @nr_ptnote: buffer for the number of PT_NOTE program headers
+ * @sz_ptnote: buffer for size of unique PT_NOTE program header
+ *
+ * This function is used to merge multiple PT_NOTE program headers
+ * into a unique single one. The resulting unique entry will have
+ * @sz_ptnote in its phdr->p_mem.
+ *
+ * It is assumed that program headers with PT_NOTE type pointed to by
+ * @ehdr_ptr has already been updated by update_note_header_size_elf32
+ * and each of PT_NOTE program headers has actual ELF note segment
+ * size in its p_memsz member.
+ */
+static int __init get_note_number_and_size_elf32(const Elf32_Ehdr *ehdr_ptr,
+						 int *nr_ptnote, u64 *sz_ptnote)
+{
+	int i;
+	Elf32_Phdr *phdr_ptr;
+
+	*nr_ptnote = *sz_ptnote = 0;
+
+	phdr_ptr = (Elf32_Phdr *)(ehdr_ptr + 1);
+	for (i = 0; i < ehdr_ptr->e_phnum; i++, phdr_ptr++) {
+		if (phdr_ptr->p_type != PT_NOTE)
+			continue;
+		*nr_ptnote += 1;
+		*sz_ptnote += phdr_ptr->p_memsz;
+	}
+
+	return 0;
+}
+
+/**
+ * copy_notes_elf32 - copy ELF note segments in a given buffer
+ *
+ * @ehdr_ptr: ELF header
+ * @notes_buf: buffer into which ELF note segments are copied
+ *
+ * This function is used to copy ELF note segment in the 1st kernel
+ * into the buffer @notes_buf in the 2nd kernel. It is assumed that
+ * size of the buffer @notes_buf is equal to or larger than sum of the
+ * real ELF note segment headers and data.
+ *
+ * It is assumed that program headers with PT_NOTE type pointed to by
+ * @ehdr_ptr has already been updated by update_note_header_size_elf32
+ * and each of PT_NOTE program headers has actual ELF note segment
+ * size in its p_memsz member.
+ */
+static int __init copy_notes_elf32(const Elf32_Ehdr *ehdr_ptr, char *notes_buf)
+{
+	int i, rc=0;
+	Elf32_Phdr *phdr_ptr;
+
+	phdr_ptr = (Elf32_Phdr*)(ehdr_ptr + 1);
+
+	for (i = 0; i < ehdr_ptr->e_phnum; i++, phdr_ptr++) {
+		u64 offset;
+		if (phdr_ptr->p_type != PT_NOTE)
+			continue;
+		offset = phdr_ptr->p_offset;
+		rc = elfcorehdr_read_notes(notes_buf, phdr_ptr->p_memsz,
+					   &offset);
+		if (rc < 0)
+			return rc;
+		notes_buf += phdr_ptr->p_memsz;
+	}
+
+	return 0;
+}
+
+/* Merges all the PT_NOTE headers into one. */
+static int __init merge_note_headers_elf32(char *elfptr, size_t *elfsz,
+					   char **notes_buf, size_t *notes_sz)
+{
+	int i, nr_ptnote=0, rc=0;
+	char *tmp;
+	Elf32_Ehdr *ehdr_ptr;
+	Elf32_Phdr phdr;
+	u64 phdr_sz = 0, note_off;
+
+	ehdr_ptr = (Elf32_Ehdr *)elfptr;
+
+	rc = update_note_header_size_elf32(ehdr_ptr);
+	if (rc < 0)
+		return rc;
+
+	rc = get_note_number_and_size_elf32(ehdr_ptr, &nr_ptnote, &phdr_sz);
+	if (rc < 0)
+		return rc;
+
+	*notes_sz = roundup(phdr_sz, PAGE_SIZE);
+	*notes_buf = vmcore_alloc_buf(*notes_sz);
+	if (!*notes_buf)
+		return -ENOMEM;
+
+	rc = copy_notes_elf32(ehdr_ptr, *notes_buf);
+	if (rc < 0)
+		return rc;
+
+	/* Prepare merged PT_NOTE program header. */
+	phdr.p_type    = PT_NOTE;
+	phdr.p_flags   = 0;
+	note_off = sizeof(Elf32_Ehdr) +
+			(ehdr_ptr->e_phnum - nr_ptnote +1) * sizeof(Elf32_Phdr);
+	phdr.p_offset  = roundup(note_off, PAGE_SIZE);
+	phdr.p_vaddr   = phdr.p_paddr = 0;
+	phdr.p_filesz  = phdr.p_memsz = phdr_sz;
+	phdr.p_align   = 0;
+
+	/* Add merged PT_NOTE program header*/
+	tmp = elfptr + sizeof(Elf32_Ehdr);
+	memcpy(tmp, &phdr, sizeof(phdr));
+	tmp += sizeof(phdr);
+
+	/* Remove unwanted PT_NOTE program headers. */
+	i = (nr_ptnote - 1) * sizeof(Elf32_Phdr);
+	*elfsz = *elfsz - i;
+	memmove(tmp, tmp+i, ((*elfsz)-sizeof(Elf32_Ehdr)-sizeof(Elf32_Phdr)));
+	memset(elfptr + *elfsz, 0, i);
+	*elfsz = roundup(*elfsz, PAGE_SIZE);
+
+	/* Modify e_phnum to reflect merged headers. */
+	ehdr_ptr->e_phnum = ehdr_ptr->e_phnum - nr_ptnote + 1;
+
+	/* Store the size of all notes.  We need this to update the note
+	 * header when the device dumps will be added.
+	 */
+	elfnotes_orig_sz = phdr.p_memsz;
+
+	return 0;
+}
+
+/* Add memory chunks represented by program headers to vmcore list. Also update
+ * the new offset fields of exported program headers. */
+static int __init process_ptload_program_headers_elf64(char *elfptr,
+						size_t elfsz,
+						size_t elfnotes_sz,
+						struct list_head *vc_list)
+{
+	int i;
+	Elf64_Ehdr *ehdr_ptr;
+	Elf64_Phdr *phdr_ptr;
+	loff_t vmcore_off;
+	struct vmcore *new;
+
+	ehdr_ptr = (Elf64_Ehdr *)elfptr;
+	phdr_ptr = (Elf64_Phdr*)(elfptr + sizeof(Elf64_Ehdr)); /* PT_NOTE hdr */
+
+	/* Skip Elf header, program headers and Elf note segment. */
+	vmcore_off = elfsz + elfnotes_sz;
+
+	for (i = 0; i < ehdr_ptr->e_phnum; i++, phdr_ptr++) {
+		u64 paddr, start, end, size;
+
+		if (phdr_ptr->p_type != PT_LOAD)
+			continue;
+
+		paddr = phdr_ptr->p_offset;
+		start = rounddown(paddr, PAGE_SIZE);
+		end = roundup(paddr + phdr_ptr->p_memsz, PAGE_SIZE);
+		size = end - start;
+
+		/* Add this contiguous chunk of memory to vmcore list.*/
+		new = get_new_element();
+		if (!new)
+			return -ENOMEM;
+		new->paddr = start;
+		new->size = size;
+		list_add_tail(&new->list, vc_list);
+
+		/* Update the program header offset. */
+		phdr_ptr->p_offset = vmcore_off + (paddr - start);
+		vmcore_off = vmcore_off + size;
+	}
+	return 0;
+}
+
+static int __init process_ptload_program_headers_elf32(char *elfptr,
+						size_t elfsz,
+						size_t elfnotes_sz,
+						struct list_head *vc_list)
+{
+	int i;
+	Elf32_Ehdr *ehdr_ptr;
+	Elf32_Phdr *phdr_ptr;
+	loff_t vmcore_off;
+	struct vmcore *new;
+
+	ehdr_ptr = (Elf32_Ehdr *)elfptr;
+	phdr_ptr = (Elf32_Phdr*)(elfptr + sizeof(Elf32_Ehdr)); /* PT_NOTE hdr */
+
+	/* Skip Elf header, program headers and Elf note segment. */
+	vmcore_off = elfsz + elfnotes_sz;
+
+	for (i = 0; i < ehdr_ptr->e_phnum; i++, phdr_ptr++) {
+		u64 paddr, start, end, size;
+
+		if (phdr_ptr->p_type != PT_LOAD)
+			continue;
+
+		paddr = phdr_ptr->p_offset;
+		start = rounddown(paddr, PAGE_SIZE);
+		end = roundup(paddr + phdr_ptr->p_memsz, PAGE_SIZE);
+		size = end - start;
+
+		/* Add this contiguous chunk of memory to vmcore list.*/
+		new = get_new_element();
+		if (!new)
+			return -ENOMEM;
+		new->paddr = start;
+		new->size = size;
+		list_add_tail(&new->list, vc_list);
+
+		/* Update the program header offset */
+		phdr_ptr->p_offset = vmcore_off + (paddr - start);
+		vmcore_off = vmcore_off + size;
+	}
+	return 0;
+}
+
+/* Sets offset fields of vmcore elements. */
+static void set_vmcore_list_offsets(size_t elfsz, size_t elfnotes_sz,
+				    struct list_head *vc_list)
+{
+	loff_t vmcore_off;
+	struct vmcore *m;
+
+	/* Skip Elf header, program headers and Elf note segment. */
+	vmcore_off = elfsz + elfnotes_sz;
+
+	list_for_each_entry(m, vc_list, list) {
+		m->offset = vmcore_off;
+		vmcore_off += m->size;
+	}
+}
+
+static void free_elfcorebuf(void)
+{
+	free_pages((unsigned long)elfcorebuf, get_order(elfcorebuf_sz_orig));
+	elfcorebuf = NULL;
+	vfree(elfnotes_buf);
+	elfnotes_buf = NULL;
+}
+
+static int __init parse_crash_elf64_headers(void)
+{
+	int rc=0;
+	Elf64_Ehdr ehdr;
+	u64 addr;
+
+	addr = elfcorehdr_addr;
+
+	/* Read Elf header */
+	rc = elfcorehdr_read((char *)&ehdr, sizeof(Elf64_Ehdr), &addr);
+	if (rc < 0)
+		return rc;
+
+	/* Do some basic Verification. */
+	if (memcmp(ehdr.e_ident, ELFMAG, SELFMAG) != 0 ||
+		(ehdr.e_type != ET_CORE) ||
+		!vmcore_elf64_check_arch(&ehdr) ||
+		ehdr.e_ident[EI_CLASS] != ELFCLASS64 ||
+		ehdr.e_ident[EI_VERSION] != EV_CURRENT ||
+		ehdr.e_version != EV_CURRENT ||
+		ehdr.e_ehsize != sizeof(Elf64_Ehdr) ||
+		ehdr.e_phentsize != sizeof(Elf64_Phdr) ||
+		ehdr.e_phnum == 0) {
+		pr_warn("Warning: Core image elf header is not sane\n");
+		return -EINVAL;
+	}
+
+	/* Read in all elf headers. */
+	elfcorebuf_sz_orig = sizeof(Elf64_Ehdr) +
+				ehdr.e_phnum * sizeof(Elf64_Phdr);
+	elfcorebuf_sz = elfcorebuf_sz_orig;
+	elfcorebuf = (void *)__get_free_pages(GFP_KERNEL | __GFP_ZERO,
+					      get_order(elfcorebuf_sz_orig));
+	if (!elfcorebuf)
+		return -ENOMEM;
+	addr = elfcorehdr_addr;
+	rc = elfcorehdr_read(elfcorebuf, elfcorebuf_sz_orig, &addr);
+	if (rc < 0)
+		goto fail;
+
+	/* Merge all PT_NOTE headers into one. */
+	rc = merge_note_headers_elf64(elfcorebuf, &elfcorebuf_sz,
+				      &elfnotes_buf, &elfnotes_sz);
+	if (rc)
+		goto fail;
+	rc = process_ptload_program_headers_elf64(elfcorebuf, elfcorebuf_sz,
+						  elfnotes_sz, &vmcore_list);
+	if (rc)
+		goto fail;
+	set_vmcore_list_offsets(elfcorebuf_sz, elfnotes_sz, &vmcore_list);
+	return 0;
+fail:
+	free_elfcorebuf();
+	return rc;
+}
+
+static int __init parse_crash_elf32_headers(void)
+{
+	int rc=0;
+	Elf32_Ehdr ehdr;
+	u64 addr;
+
+	addr = elfcorehdr_addr;
+
+	/* Read Elf header */
+	rc = elfcorehdr_read((char *)&ehdr, sizeof(Elf32_Ehdr), &addr);
+	if (rc < 0)
+		return rc;
+
+	/* Do some basic Verification. */
+	if (memcmp(ehdr.e_ident, ELFMAG, SELFMAG) != 0 ||
+		(ehdr.e_type != ET_CORE) ||
+		!vmcore_elf32_check_arch(&ehdr) ||
+		ehdr.e_ident[EI_CLASS] != ELFCLASS32||
+		ehdr.e_ident[EI_VERSION] != EV_CURRENT ||
+		ehdr.e_version != EV_CURRENT ||
+		ehdr.e_ehsize != sizeof(Elf32_Ehdr) ||
+		ehdr.e_phentsize != sizeof(Elf32_Phdr) ||
+		ehdr.e_phnum == 0) {
+		pr_warn("Warning: Core image elf header is not sane\n");
+		return -EINVAL;
+	}
+
+	/* Read in all elf headers. */
+	elfcorebuf_sz_orig = sizeof(Elf32_Ehdr) + ehdr.e_phnum * sizeof(Elf32_Phdr);
+	elfcorebuf_sz = elfcorebuf_sz_orig;
+	elfcorebuf = (void *)__get_free_pages(GFP_KERNEL | __GFP_ZERO,
+					      get_order(elfcorebuf_sz_orig));
+	if (!elfcorebuf)
+		return -ENOMEM;
+	addr = elfcorehdr_addr;
+	rc = elfcorehdr_read(elfcorebuf, elfcorebuf_sz_orig, &addr);
+	if (rc < 0)
+		goto fail;
+
+	/* Merge all PT_NOTE headers into one. */
+	rc = merge_note_headers_elf32(elfcorebuf, &elfcorebuf_sz,
+				      &elfnotes_buf, &elfnotes_sz);
+	if (rc)
+		goto fail;
+	rc = process_ptload_program_headers_elf32(elfcorebuf, elfcorebuf_sz,
+						  elfnotes_sz, &vmcore_list);
+	if (rc)
+		goto fail;
+	set_vmcore_list_offsets(elfcorebuf_sz, elfnotes_sz, &vmcore_list);
+	return 0;
+fail:
+	free_elfcorebuf();
+	return rc;
+}
+
+static int __init parse_crash_elf_headers(void)
+{
+	unsigned char e_ident[EI_NIDENT];
+	u64 addr;
+	int rc=0;
+
+	addr = elfcorehdr_addr;
+	rc = elfcorehdr_read(e_ident, EI_NIDENT, &addr);
+	if (rc < 0)
+		return rc;
+	if (memcmp(e_ident, ELFMAG, SELFMAG) != 0) {
+		pr_warn("Warning: Core image elf header not found\n");
+		return -EINVAL;
+	}
+
+	if (e_ident[EI_CLASS] == ELFCLASS64) {
+		rc = parse_crash_elf64_headers();
+		if (rc)
+			return rc;
+	} else if (e_ident[EI_CLASS] == ELFCLASS32) {
+		rc = parse_crash_elf32_headers();
+		if (rc)
+			return rc;
+	} else {
+		pr_warn("Warning: Core image elf header is not sane\n");
+		return -EINVAL;
+	}
+
+	/* Determine vmcore size. */
+	vmcore_size = get_vmcore_size(elfcorebuf_sz, elfnotes_sz,
+				      &vmcore_list);
+
+	return 0;
+}
+
+#ifdef CONFIG_PROC_VMCORE_DEVICE_DUMP
+/**
+ * vmcoredd_write_header - Write vmcore device dump header at the
+ * beginning of the dump's buffer.
+ * @buf: Output buffer where the note is written
+ * @data: Dump info
+ * @size: Size of the dump
+ *
+ * Fills beginning of the dump's buffer with vmcore device dump header.
+ */
+static void vmcoredd_write_header(void *buf, struct vmcoredd_data *data,
+				  u32 size)
+{
+	struct vmcoredd_header *vdd_hdr = (struct vmcoredd_header *)buf;
+
+	vdd_hdr->n_namesz = sizeof(vdd_hdr->name);
+	vdd_hdr->n_descsz = size + sizeof(vdd_hdr->dump_name);
+	vdd_hdr->n_type = NT_VMCOREDD;
+
+	strncpy((char *)vdd_hdr->name, VMCOREDD_NOTE_NAME,
+		sizeof(vdd_hdr->name));
+	memcpy(vdd_hdr->dump_name, data->dump_name, sizeof(vdd_hdr->dump_name));
+}
+
+/**
+ * vmcoredd_update_program_headers - Update all Elf program headers
+ * @elfptr: Pointer to elf header
+ * @elfnotesz: Size of elf notes aligned to page size
+ * @vmcoreddsz: Size of device dumps to be added to elf note header
+ *
+ * Determine type of Elf header (Elf64 or Elf32) and update the elf note size.
+ * Also update the offsets of all the program headers after the elf note header.
+ */
+static void vmcoredd_update_program_headers(char *elfptr, size_t elfnotesz,
+					    size_t vmcoreddsz)
+{
+	unsigned char *e_ident = (unsigned char *)elfptr;
+	u64 start, end, size;
+	loff_t vmcore_off;
+	u32 i;
+
+	vmcore_off = elfcorebuf_sz + elfnotesz;
+
+	if (e_ident[EI_CLASS] == ELFCLASS64) {
+		Elf64_Ehdr *ehdr = (Elf64_Ehdr *)elfptr;
+		Elf64_Phdr *phdr = (Elf64_Phdr *)(elfptr + sizeof(Elf64_Ehdr));
+
+		/* Update all program headers */
+		for (i = 0; i < ehdr->e_phnum; i++, phdr++) {
+			if (phdr->p_type == PT_NOTE) {
+				/* Update note size */
+				phdr->p_memsz = elfnotes_orig_sz + vmcoreddsz;
+				phdr->p_filesz = phdr->p_memsz;
+				continue;
+			}
+
+			start = rounddown(phdr->p_offset, PAGE_SIZE);
+			end = roundup(phdr->p_offset + phdr->p_memsz,
+				      PAGE_SIZE);
+			size = end - start;
+			phdr->p_offset = vmcore_off + (phdr->p_offset - start);
+			vmcore_off += size;
+		}
+	} else {
+		Elf32_Ehdr *ehdr = (Elf32_Ehdr *)elfptr;
+		Elf32_Phdr *phdr = (Elf32_Phdr *)(elfptr + sizeof(Elf32_Ehdr));
+
+		/* Update all program headers */
+		for (i = 0; i < ehdr->e_phnum; i++, phdr++) {
+			if (phdr->p_type == PT_NOTE) {
+				/* Update note size */
+				phdr->p_memsz = elfnotes_orig_sz + vmcoreddsz;
+				phdr->p_filesz = phdr->p_memsz;
+				continue;
+			}
+
+			start = rounddown(phdr->p_offset, PAGE_SIZE);
+			end = roundup(phdr->p_offset + phdr->p_memsz,
+				      PAGE_SIZE);
+			size = end - start;
+			phdr->p_offset = vmcore_off + (phdr->p_offset - start);
+			vmcore_off += size;
+		}
+	}
+}
+
+/**
+ * vmcoredd_update_size - Update the total size of the device dumps and update
+ * Elf header
+ * @dump_size: Size of the current device dump to be added to total size
+ *
+ * Update the total size of all the device dumps and update the Elf program
+ * headers. Calculate the new offsets for the vmcore list and update the
+ * total vmcore size.
+ */
+static void vmcoredd_update_size(size_t dump_size)
+{
+	vmcoredd_orig_sz += dump_size;
+	elfnotes_sz = roundup(elfnotes_orig_sz, PAGE_SIZE) + vmcoredd_orig_sz;
+	vmcoredd_update_program_headers(elfcorebuf, elfnotes_sz,
+					vmcoredd_orig_sz);
+
+	/* Update vmcore list offsets */
+	set_vmcore_list_offsets(elfcorebuf_sz, elfnotes_sz, &vmcore_list);
+
+	vmcore_size = get_vmcore_size(elfcorebuf_sz, elfnotes_sz,
+				      &vmcore_list);
+	proc_vmcore->size = vmcore_size;
+}
+
+/**
+ * vmcore_add_device_dump - Add a buffer containing device dump to vmcore
+ * @data: dump info.
+ *
+ * Allocate a buffer and invoke the calling driver's dump collect routine.
+ * Write Elf note at the beginning of the buffer to indicate vmcore device
+ * dump and add the dump to global list.
+ */
+int vmcore_add_device_dump(struct vmcoredd_data *data)
+{
+	struct vmcoredd_node *dump;
+	void *buf = NULL;
+	size_t data_size;
+	int ret;
+
+	if (vmcoredd_disabled) {
+		pr_err_once("Device dump is disabled\n");
+		return -EINVAL;
+	}
+
+	if (!data || !strlen(data->dump_name) ||
+	    !data->vmcoredd_callback || !data->size)
+		return -EINVAL;
+
+	dump = vzalloc(sizeof(*dump));
+	if (!dump) {
+		ret = -ENOMEM;
+		goto out_err;
+	}
+
+	/* Keep size of the buffer page aligned so that it can be mmaped */
+	data_size = roundup(sizeof(struct vmcoredd_header) + data->size,
+			    PAGE_SIZE);
+
+	/* Allocate buffer for driver's to write their dumps */
+	buf = vmcore_alloc_buf(data_size);
+	if (!buf) {
+		ret = -ENOMEM;
+		goto out_err;
+	}
+
+	vmcoredd_write_header(buf, data, data_size -
+			      sizeof(struct vmcoredd_header));
+
+	/* Invoke the driver's dump collection routing */
+	ret = data->vmcoredd_callback(data, buf +
+				      sizeof(struct vmcoredd_header));
+	if (ret)
+		goto out_err;
+
+	dump->buf = buf;
+	dump->size = data_size;
+
+	/* Add the dump to driver sysfs list */
+	mutex_lock(&vmcoredd_mutex);
+	list_add_tail(&dump->list, &vmcoredd_list);
+	mutex_unlock(&vmcoredd_mutex);
+
+	vmcoredd_update_size(data_size);
+	return 0;
+
+out_err:
+	vfree(buf);
+	vfree(dump);
+
+	return ret;
+}
+EXPORT_SYMBOL(vmcore_add_device_dump);
+#endif /* CONFIG_PROC_VMCORE_DEVICE_DUMP */
+
+/* Free all dumps in vmcore device dump list */
+static void vmcore_free_device_dumps(void)
+{
+#ifdef CONFIG_PROC_VMCORE_DEVICE_DUMP
+	mutex_lock(&vmcoredd_mutex);
+	while (!list_empty(&vmcoredd_list)) {
+		struct vmcoredd_node *dump;
+
+		dump = list_first_entry(&vmcoredd_list, struct vmcoredd_node,
+					list);
+		list_del(&dump->list);
+		vfree(dump->buf);
+		vfree(dump);
+	}
+	mutex_unlock(&vmcoredd_mutex);
+#endif /* CONFIG_PROC_VMCORE_DEVICE_DUMP */
+}
+
+/* Init function for vmcore module. */
+static int __init vmcore_init(void)
+{
+	int rc = 0;
+
+	/* Allow architectures to allocate ELF header in 2nd kernel */
+	rc = elfcorehdr_alloc(&elfcorehdr_addr, &elfcorehdr_size);
+	if (rc)
+		return rc;
+	/*
+	 * If elfcorehdr= has been passed in cmdline or created in 2nd kernel,
+	 * then capture the dump.
+	 */
+	if (!(is_vmcore_usable()))
+		return rc;
+	rc = parse_crash_elf_headers();
+	if (rc) {
+		pr_warn("Kdump: vmcore not initialized\n");
+		return rc;
+	}
+	elfcorehdr_free(elfcorehdr_addr);
+	elfcorehdr_addr = ELFCORE_ADDR_ERR;
+
+	proc_vmcore = proc_create("vmcore", S_IRUSR, NULL, &vmcore_proc_ops);
+	if (proc_vmcore)
+		proc_vmcore->size = vmcore_size;
+	return 0;
+}
+fs_initcall(vmcore_init);
+
+/* Cleanup function for vmcore module. */
+void vmcore_cleanup(void)
+{
+	if (proc_vmcore) {
+		proc_remove(proc_vmcore);
+		proc_vmcore = NULL;
+	}
+
+	/* clear the vmcore list. */
+	while (!list_empty(&vmcore_list)) {
+		struct vmcore *m;
+
+		m = list_first_entry(&vmcore_list, struct vmcore, list);
+		list_del(&m->list);
+		kfree(m);
+	}
+	free_elfcorebuf();
+
+	/* clear vmcore device dump list */
+	vmcore_free_device_dumps();
+}