Adding upstream version 6.1.76.upstream/6.1.76

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

1 files changed, 1042 insertions, 0 deletions

diff --git a/arch/x86/kernel/process.c b/arch/x86/kernel/process.c
new file mode 100644
index 000000000..279b5e9be
--- /dev/null
+++ b/arch/x86/kernel/process.c
@@ -0,0 +1,1042 @@
+// SPDX-License-Identifier: GPL-2.0
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/errno.h>
+#include <linux/kernel.h>
+#include <linux/mm.h>
+#include <linux/smp.h>
+#include <linux/prctl.h>
+#include <linux/slab.h>
+#include <linux/sched.h>
+#include <linux/sched/idle.h>
+#include <linux/sched/debug.h>
+#include <linux/sched/task.h>
+#include <linux/sched/task_stack.h>
+#include <linux/init.h>
+#include <linux/export.h>
+#include <linux/pm.h>
+#include <linux/tick.h>
+#include <linux/random.h>
+#include <linux/user-return-notifier.h>
+#include <linux/dmi.h>
+#include <linux/utsname.h>
+#include <linux/stackprotector.h>
+#include <linux/cpuidle.h>
+#include <linux/acpi.h>
+#include <linux/elf-randomize.h>
+#include <trace/events/power.h>
+#include <linux/hw_breakpoint.h>
+#include <asm/cpu.h>
+#include <asm/apic.h>
+#include <linux/uaccess.h>
+#include <asm/mwait.h>
+#include <asm/fpu/api.h>
+#include <asm/fpu/sched.h>
+#include <asm/fpu/xstate.h>
+#include <asm/debugreg.h>
+#include <asm/nmi.h>
+#include <asm/tlbflush.h>
+#include <asm/mce.h>
+#include <asm/vm86.h>
+#include <asm/switch_to.h>
+#include <asm/desc.h>
+#include <asm/prctl.h>
+#include <asm/spec-ctrl.h>
+#include <asm/io_bitmap.h>
+#include <asm/proto.h>
+#include <asm/frame.h>
+#include <asm/unwind.h>
+#include <asm/tdx.h>
+
+#include "process.h"
+
+/*
+ * per-CPU TSS segments. Threads are completely 'soft' on Linux,
+ * no more per-task TSS's. The TSS size is kept cacheline-aligned
+ * so they are allowed to end up in the .data..cacheline_aligned
+ * section. Since TSS's are completely CPU-local, we want them
+ * on exact cacheline boundaries, to eliminate cacheline ping-pong.
+ */
+__visible DEFINE_PER_CPU_PAGE_ALIGNED(struct tss_struct, cpu_tss_rw) = {
+	.x86_tss = {
+		/*
+		 * .sp0 is only used when entering ring 0 from a lower
+		 * privilege level.  Since the init task never runs anything
+		 * but ring 0 code, there is no need for a valid value here.
+		 * Poison it.
+		 */
+		.sp0 = (1UL << (BITS_PER_LONG-1)) + 1,
+
+#ifdef CONFIG_X86_32
+		.sp1 = TOP_OF_INIT_STACK,
+
+		.ss0 = __KERNEL_DS,
+		.ss1 = __KERNEL_CS,
+#endif
+		.io_bitmap_base	= IO_BITMAP_OFFSET_INVALID,
+	 },
+};
+EXPORT_PER_CPU_SYMBOL(cpu_tss_rw);
+
+DEFINE_PER_CPU(bool, __tss_limit_invalid);
+EXPORT_PER_CPU_SYMBOL_GPL(__tss_limit_invalid);
+
+/*
+ * this gets called so that we can store lazy state into memory and copy the
+ * current task into the new thread.
+ */
+int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src)
+{
+	memcpy(dst, src, arch_task_struct_size);
+#ifdef CONFIG_VM86
+	dst->thread.vm86 = NULL;
+#endif
+	/* Drop the copied pointer to current's fpstate */
+	dst->thread.fpu.fpstate = NULL;
+
+	return 0;
+}
+
+#ifdef CONFIG_X86_64
+void arch_release_task_struct(struct task_struct *tsk)
+{
+	if (fpu_state_size_dynamic())
+		fpstate_free(&tsk->thread.fpu);
+}
+#endif
+
+/*
+ * Free thread data structures etc..
+ */
+void exit_thread(struct task_struct *tsk)
+{
+	struct thread_struct *t = &tsk->thread;
+	struct fpu *fpu = &t->fpu;
+
+	if (test_thread_flag(TIF_IO_BITMAP))
+		io_bitmap_exit(tsk);
+
+	free_vm86(t);
+
+	fpu__drop(fpu);
+}
+
+static int set_new_tls(struct task_struct *p, unsigned long tls)
+{
+	struct user_desc __user *utls = (struct user_desc __user *)tls;
+
+	if (in_ia32_syscall())
+		return do_set_thread_area(p, -1, utls, 0);
+	else
+		return do_set_thread_area_64(p, ARCH_SET_FS, tls);
+}
+
+int copy_thread(struct task_struct *p, const struct kernel_clone_args *args)
+{
+	unsigned long clone_flags = args->flags;
+	unsigned long sp = args->stack;
+	unsigned long tls = args->tls;
+	struct inactive_task_frame *frame;
+	struct fork_frame *fork_frame;
+	struct pt_regs *childregs;
+	int ret = 0;
+
+	childregs = task_pt_regs(p);
+	fork_frame = container_of(childregs, struct fork_frame, regs);
+	frame = &fork_frame->frame;
+
+	frame->bp = encode_frame_pointer(childregs);
+	frame->ret_addr = (unsigned long) ret_from_fork;
+	p->thread.sp = (unsigned long) fork_frame;
+	p->thread.io_bitmap = NULL;
+	p->thread.iopl_warn = 0;
+	memset(p->thread.ptrace_bps, 0, sizeof(p->thread.ptrace_bps));
+
+#ifdef CONFIG_X86_64
+	current_save_fsgs();
+	p->thread.fsindex = current->thread.fsindex;
+	p->thread.fsbase = current->thread.fsbase;
+	p->thread.gsindex = current->thread.gsindex;
+	p->thread.gsbase = current->thread.gsbase;
+
+	savesegment(es, p->thread.es);
+	savesegment(ds, p->thread.ds);
+#else
+	p->thread.sp0 = (unsigned long) (childregs + 1);
+	savesegment(gs, p->thread.gs);
+	/*
+	 * Clear all status flags including IF and set fixed bit. 64bit
+	 * does not have this initialization as the frame does not contain
+	 * flags. The flags consistency (especially vs. AC) is there
+	 * ensured via objtool, which lacks 32bit support.
+	 */
+	frame->flags = X86_EFLAGS_FIXED;
+#endif
+
+	fpu_clone(p, clone_flags, args->fn);
+
+	/* Kernel thread ? */
+	if (unlikely(p->flags & PF_KTHREAD)) {
+		p->thread.pkru = pkru_get_init_value();
+		memset(childregs, 0, sizeof(struct pt_regs));
+		kthread_frame_init(frame, args->fn, args->fn_arg);
+		return 0;
+	}
+
+	/*
+	 * Clone current's PKRU value from hardware. tsk->thread.pkru
+	 * is only valid when scheduled out.
+	 */
+	p->thread.pkru = read_pkru();
+
+	frame->bx = 0;
+	*childregs = *current_pt_regs();
+	childregs->ax = 0;
+	if (sp)
+		childregs->sp = sp;
+
+	if (unlikely(args->fn)) {
+		/*
+		 * A user space thread, but it doesn't return to
+		 * ret_after_fork().
+		 *
+		 * In order to indicate that to tools like gdb,
+		 * we reset the stack and instruction pointers.
+		 *
+		 * It does the same kernel frame setup to return to a kernel
+		 * function that a kernel thread does.
+		 */
+		childregs->sp = 0;
+		childregs->ip = 0;
+		kthread_frame_init(frame, args->fn, args->fn_arg);
+		return 0;
+	}
+
+	/* Set a new TLS for the child thread? */
+	if (clone_flags & CLONE_SETTLS)
+		ret = set_new_tls(p, tls);
+
+	if (!ret && unlikely(test_tsk_thread_flag(current, TIF_IO_BITMAP)))
+		io_bitmap_share(p);
+
+	return ret;
+}
+
+static void pkru_flush_thread(void)
+{
+	/*
+	 * If PKRU is enabled the default PKRU value has to be loaded into
+	 * the hardware right here (similar to context switch).
+	 */
+	pkru_write_default();
+}
+
+void flush_thread(void)
+{
+	struct task_struct *tsk = current;
+
+	flush_ptrace_hw_breakpoint(tsk);
+	memset(tsk->thread.tls_array, 0, sizeof(tsk->thread.tls_array));
+
+	fpu_flush_thread();
+	pkru_flush_thread();
+}
+
+void disable_TSC(void)
+{
+	preempt_disable();
+	if (!test_and_set_thread_flag(TIF_NOTSC))
+		/*
+		 * Must flip the CPU state synchronously with
+		 * TIF_NOTSC in the current running context.
+		 */
+		cr4_set_bits(X86_CR4_TSD);
+	preempt_enable();
+}
+
+static void enable_TSC(void)
+{
+	preempt_disable();
+	if (test_and_clear_thread_flag(TIF_NOTSC))
+		/*
+		 * Must flip the CPU state synchronously with
+		 * TIF_NOTSC in the current running context.
+		 */
+		cr4_clear_bits(X86_CR4_TSD);
+	preempt_enable();
+}
+
+int get_tsc_mode(unsigned long adr)
+{
+	unsigned int val;
+
+	if (test_thread_flag(TIF_NOTSC))
+		val = PR_TSC_SIGSEGV;
+	else
+		val = PR_TSC_ENABLE;
+
+	return put_user(val, (unsigned int __user *)adr);
+}
+
+int set_tsc_mode(unsigned int val)
+{
+	if (val == PR_TSC_SIGSEGV)
+		disable_TSC();
+	else if (val == PR_TSC_ENABLE)
+		enable_TSC();
+	else
+		return -EINVAL;
+
+	return 0;
+}
+
+DEFINE_PER_CPU(u64, msr_misc_features_shadow);
+
+static void set_cpuid_faulting(bool on)
+{
+	u64 msrval;
+
+	msrval = this_cpu_read(msr_misc_features_shadow);
+	msrval &= ~MSR_MISC_FEATURES_ENABLES_CPUID_FAULT;
+	msrval |= (on << MSR_MISC_FEATURES_ENABLES_CPUID_FAULT_BIT);
+	this_cpu_write(msr_misc_features_shadow, msrval);
+	wrmsrl(MSR_MISC_FEATURES_ENABLES, msrval);
+}
+
+static void disable_cpuid(void)
+{
+	preempt_disable();
+	if (!test_and_set_thread_flag(TIF_NOCPUID)) {
+		/*
+		 * Must flip the CPU state synchronously with
+		 * TIF_NOCPUID in the current running context.
+		 */
+		set_cpuid_faulting(true);
+	}
+	preempt_enable();
+}
+
+static void enable_cpuid(void)
+{
+	preempt_disable();
+	if (test_and_clear_thread_flag(TIF_NOCPUID)) {
+		/*
+		 * Must flip the CPU state synchronously with
+		 * TIF_NOCPUID in the current running context.
+		 */
+		set_cpuid_faulting(false);
+	}
+	preempt_enable();
+}
+
+static int get_cpuid_mode(void)
+{
+	return !test_thread_flag(TIF_NOCPUID);
+}
+
+static int set_cpuid_mode(unsigned long cpuid_enabled)
+{
+	if (!boot_cpu_has(X86_FEATURE_CPUID_FAULT))
+		return -ENODEV;
+
+	if (cpuid_enabled)
+		enable_cpuid();
+	else
+		disable_cpuid();
+
+	return 0;
+}
+
+/*
+ * Called immediately after a successful exec.
+ */
+void arch_setup_new_exec(void)
+{
+	/* If cpuid was previously disabled for this task, re-enable it. */
+	if (test_thread_flag(TIF_NOCPUID))
+		enable_cpuid();
+
+	/*
+	 * Don't inherit TIF_SSBD across exec boundary when
+	 * PR_SPEC_DISABLE_NOEXEC is used.
+	 */
+	if (test_thread_flag(TIF_SSBD) &&
+	    task_spec_ssb_noexec(current)) {
+		clear_thread_flag(TIF_SSBD);
+		task_clear_spec_ssb_disable(current);
+		task_clear_spec_ssb_noexec(current);
+		speculation_ctrl_update(read_thread_flags());
+	}
+}
+
+#ifdef CONFIG_X86_IOPL_IOPERM
+static inline void switch_to_bitmap(unsigned long tifp)
+{
+	/*
+	 * Invalidate I/O bitmap if the previous task used it. This prevents
+	 * any possible leakage of an active I/O bitmap.
+	 *
+	 * If the next task has an I/O bitmap it will handle it on exit to
+	 * user mode.
+	 */
+	if (tifp & _TIF_IO_BITMAP)
+		tss_invalidate_io_bitmap();
+}
+
+static void tss_copy_io_bitmap(struct tss_struct *tss, struct io_bitmap *iobm)
+{
+	/*
+	 * Copy at least the byte range of the incoming tasks bitmap which
+	 * covers the permitted I/O ports.
+	 *
+	 * If the previous task which used an I/O bitmap had more bits
+	 * permitted, then the copy needs to cover those as well so they
+	 * get turned off.
+	 */
+	memcpy(tss->io_bitmap.bitmap, iobm->bitmap,
+	       max(tss->io_bitmap.prev_max, iobm->max));
+
+	/*
+	 * Store the new max and the sequence number of this bitmap
+	 * and a pointer to the bitmap itself.
+	 */
+	tss->io_bitmap.prev_max = iobm->max;
+	tss->io_bitmap.prev_sequence = iobm->sequence;
+}
+
+/**
+ * native_tss_update_io_bitmap - Update I/O bitmap before exiting to user mode
+ */
+void native_tss_update_io_bitmap(void)
+{
+	struct tss_struct *tss = this_cpu_ptr(&cpu_tss_rw);
+	struct thread_struct *t = &current->thread;
+	u16 *base = &tss->x86_tss.io_bitmap_base;
+
+	if (!test_thread_flag(TIF_IO_BITMAP)) {
+		native_tss_invalidate_io_bitmap();
+		return;
+	}
+
+	if (IS_ENABLED(CONFIG_X86_IOPL_IOPERM) && t->iopl_emul == 3) {
+		*base = IO_BITMAP_OFFSET_VALID_ALL;
+	} else {
+		struct io_bitmap *iobm = t->io_bitmap;
+
+		/*
+		 * Only copy bitmap data when the sequence number differs. The
+		 * update time is accounted to the incoming task.
+		 */
+		if (tss->io_bitmap.prev_sequence != iobm->sequence)
+			tss_copy_io_bitmap(tss, iobm);
+
+		/* Enable the bitmap */
+		*base = IO_BITMAP_OFFSET_VALID_MAP;
+	}
+
+	/*
+	 * Make sure that the TSS limit is covering the IO bitmap. It might have
+	 * been cut down by a VMEXIT to 0x67 which would cause a subsequent I/O
+	 * access from user space to trigger a #GP because tbe bitmap is outside
+	 * the TSS limit.
+	 */
+	refresh_tss_limit();
+}
+#else /* CONFIG_X86_IOPL_IOPERM */
+static inline void switch_to_bitmap(unsigned long tifp) { }
+#endif
+
+#ifdef CONFIG_SMP
+
+struct ssb_state {
+	struct ssb_state	*shared_state;
+	raw_spinlock_t		lock;
+	unsigned int		disable_state;
+	unsigned long		local_state;
+};
+
+#define LSTATE_SSB	0
+
+static DEFINE_PER_CPU(struct ssb_state, ssb_state);
+
+void speculative_store_bypass_ht_init(void)
+{
+	struct ssb_state *st = this_cpu_ptr(&ssb_state);
+	unsigned int this_cpu = smp_processor_id();
+	unsigned int cpu;
+
+	st->local_state = 0;
+
+	/*
+	 * Shared state setup happens once on the first bringup
+	 * of the CPU. It's not destroyed on CPU hotunplug.
+	 */
+	if (st->shared_state)
+		return;
+
+	raw_spin_lock_init(&st->lock);
+
+	/*
+	 * Go over HT siblings and check whether one of them has set up the
+	 * shared state pointer already.
+	 */
+	for_each_cpu(cpu, topology_sibling_cpumask(this_cpu)) {
+		if (cpu == this_cpu)
+			continue;
+
+		if (!per_cpu(ssb_state, cpu).shared_state)
+			continue;
+
+		/* Link it to the state of the sibling: */
+		st->shared_state = per_cpu(ssb_state, cpu).shared_state;
+		return;
+	}
+
+	/*
+	 * First HT sibling to come up on the core.  Link shared state of
+	 * the first HT sibling to itself. The siblings on the same core
+	 * which come up later will see the shared state pointer and link
+	 * themselves to the state of this CPU.
+	 */
+	st->shared_state = st;
+}
+
+/*
+ * Logic is: First HT sibling enables SSBD for both siblings in the core
+ * and last sibling to disable it, disables it for the whole core. This how
+ * MSR_SPEC_CTRL works in "hardware":
+ *
+ *  CORE_SPEC_CTRL = THREAD0_SPEC_CTRL | THREAD1_SPEC_CTRL
+ */
+static __always_inline void amd_set_core_ssb_state(unsigned long tifn)
+{
+	struct ssb_state *st = this_cpu_ptr(&ssb_state);
+	u64 msr = x86_amd_ls_cfg_base;
+
+	if (!static_cpu_has(X86_FEATURE_ZEN)) {
+		msr |= ssbd_tif_to_amd_ls_cfg(tifn);
+		wrmsrl(MSR_AMD64_LS_CFG, msr);
+		return;
+	}
+
+	if (tifn & _TIF_SSBD) {
+		/*
+		 * Since this can race with prctl(), block reentry on the
+		 * same CPU.
+		 */
+		if (__test_and_set_bit(LSTATE_SSB, &st->local_state))
+			return;
+
+		msr |= x86_amd_ls_cfg_ssbd_mask;
+
+		raw_spin_lock(&st->shared_state->lock);
+		/* First sibling enables SSBD: */
+		if (!st->shared_state->disable_state)
+			wrmsrl(MSR_AMD64_LS_CFG, msr);
+		st->shared_state->disable_state++;
+		raw_spin_unlock(&st->shared_state->lock);
+	} else {
+		if (!__test_and_clear_bit(LSTATE_SSB, &st->local_state))
+			return;
+
+		raw_spin_lock(&st->shared_state->lock);
+		st->shared_state->disable_state--;
+		if (!st->shared_state->disable_state)
+			wrmsrl(MSR_AMD64_LS_CFG, msr);
+		raw_spin_unlock(&st->shared_state->lock);
+	}
+}
+#else
+static __always_inline void amd_set_core_ssb_state(unsigned long tifn)
+{
+	u64 msr = x86_amd_ls_cfg_base | ssbd_tif_to_amd_ls_cfg(tifn);
+
+	wrmsrl(MSR_AMD64_LS_CFG, msr);
+}
+#endif
+
+static __always_inline void amd_set_ssb_virt_state(unsigned long tifn)
+{
+	/*
+	 * SSBD has the same definition in SPEC_CTRL and VIRT_SPEC_CTRL,
+	 * so ssbd_tif_to_spec_ctrl() just works.
+	 */
+	wrmsrl(MSR_AMD64_VIRT_SPEC_CTRL, ssbd_tif_to_spec_ctrl(tifn));
+}
+
+/*
+ * Update the MSRs managing speculation control, during context switch.
+ *
+ * tifp: Previous task's thread flags
+ * tifn: Next task's thread flags
+ */
+static __always_inline void __speculation_ctrl_update(unsigned long tifp,
+						      unsigned long tifn)
+{
+	unsigned long tif_diff = tifp ^ tifn;
+	u64 msr = x86_spec_ctrl_base;
+	bool updmsr = false;
+
+	lockdep_assert_irqs_disabled();
+
+	/* Handle change of TIF_SSBD depending on the mitigation method. */
+	if (static_cpu_has(X86_FEATURE_VIRT_SSBD)) {
+		if (tif_diff & _TIF_SSBD)
+			amd_set_ssb_virt_state(tifn);
+	} else if (static_cpu_has(X86_FEATURE_LS_CFG_SSBD)) {
+		if (tif_diff & _TIF_SSBD)
+			amd_set_core_ssb_state(tifn);
+	} else if (static_cpu_has(X86_FEATURE_SPEC_CTRL_SSBD) ||
+		   static_cpu_has(X86_FEATURE_AMD_SSBD)) {
+		updmsr |= !!(tif_diff & _TIF_SSBD);
+		msr |= ssbd_tif_to_spec_ctrl(tifn);
+	}
+
+	/* Only evaluate TIF_SPEC_IB if conditional STIBP is enabled. */
+	if (IS_ENABLED(CONFIG_SMP) &&
+	    static_branch_unlikely(&switch_to_cond_stibp)) {
+		updmsr |= !!(tif_diff & _TIF_SPEC_IB);
+		msr |= stibp_tif_to_spec_ctrl(tifn);
+	}
+
+	if (updmsr)
+		update_spec_ctrl_cond(msr);
+}
+
+static unsigned long speculation_ctrl_update_tif(struct task_struct *tsk)
+{
+	if (test_and_clear_tsk_thread_flag(tsk, TIF_SPEC_FORCE_UPDATE)) {
+		if (task_spec_ssb_disable(tsk))
+			set_tsk_thread_flag(tsk, TIF_SSBD);
+		else
+			clear_tsk_thread_flag(tsk, TIF_SSBD);
+
+		if (task_spec_ib_disable(tsk))
+			set_tsk_thread_flag(tsk, TIF_SPEC_IB);
+		else
+			clear_tsk_thread_flag(tsk, TIF_SPEC_IB);
+	}
+	/* Return the updated threadinfo flags*/
+	return read_task_thread_flags(tsk);
+}
+
+void speculation_ctrl_update(unsigned long tif)
+{
+	unsigned long flags;
+
+	/* Forced update. Make sure all relevant TIF flags are different */
+	local_irq_save(flags);
+	__speculation_ctrl_update(~tif, tif);
+	local_irq_restore(flags);
+}
+
+/* Called from seccomp/prctl update */
+void speculation_ctrl_update_current(void)
+{
+	preempt_disable();
+	speculation_ctrl_update(speculation_ctrl_update_tif(current));
+	preempt_enable();
+}
+
+static inline void cr4_toggle_bits_irqsoff(unsigned long mask)
+{
+	unsigned long newval, cr4 = this_cpu_read(cpu_tlbstate.cr4);
+
+	newval = cr4 ^ mask;
+	if (newval != cr4) {
+		this_cpu_write(cpu_tlbstate.cr4, newval);
+		__write_cr4(newval);
+	}
+}
+
+void __switch_to_xtra(struct task_struct *prev_p, struct task_struct *next_p)
+{
+	unsigned long tifp, tifn;
+
+	tifn = read_task_thread_flags(next_p);
+	tifp = read_task_thread_flags(prev_p);
+
+	switch_to_bitmap(tifp);
+
+	propagate_user_return_notify(prev_p, next_p);
+
+	if ((tifp & _TIF_BLOCKSTEP || tifn & _TIF_BLOCKSTEP) &&
+	    arch_has_block_step()) {
+		unsigned long debugctl, msk;
+
+		rdmsrl(MSR_IA32_DEBUGCTLMSR, debugctl);
+		debugctl &= ~DEBUGCTLMSR_BTF;
+		msk = tifn & _TIF_BLOCKSTEP;
+		debugctl |= (msk >> TIF_BLOCKSTEP) << DEBUGCTLMSR_BTF_SHIFT;
+		wrmsrl(MSR_IA32_DEBUGCTLMSR, debugctl);
+	}
+
+	if ((tifp ^ tifn) & _TIF_NOTSC)
+		cr4_toggle_bits_irqsoff(X86_CR4_TSD);
+
+	if ((tifp ^ tifn) & _TIF_NOCPUID)
+		set_cpuid_faulting(!!(tifn & _TIF_NOCPUID));
+
+	if (likely(!((tifp | tifn) & _TIF_SPEC_FORCE_UPDATE))) {
+		__speculation_ctrl_update(tifp, tifn);
+	} else {
+		speculation_ctrl_update_tif(prev_p);
+		tifn = speculation_ctrl_update_tif(next_p);
+
+		/* Enforce MSR update to ensure consistent state */
+		__speculation_ctrl_update(~tifn, tifn);
+	}
+}
+
+/*
+ * Idle related variables and functions
+ */
+unsigned long boot_option_idle_override = IDLE_NO_OVERRIDE;
+EXPORT_SYMBOL(boot_option_idle_override);
+
+static void (*x86_idle)(void);
+
+#ifndef CONFIG_SMP
+static inline void play_dead(void)
+{
+	BUG();
+}
+#endif
+
+void arch_cpu_idle_enter(void)
+{
+	tsc_verify_tsc_adjust(false);
+	local_touch_nmi();
+}
+
+void arch_cpu_idle_dead(void)
+{
+	play_dead();
+}
+
+/*
+ * Called from the generic idle code.
+ */
+void arch_cpu_idle(void)
+{
+	x86_idle();
+}
+
+/*
+ * We use this if we don't have any better idle routine..
+ */
+void __cpuidle default_idle(void)
+{
+	raw_safe_halt();
+}
+#if defined(CONFIG_APM_MODULE) || defined(CONFIG_HALTPOLL_CPUIDLE_MODULE)
+EXPORT_SYMBOL(default_idle);
+#endif
+
+#ifdef CONFIG_XEN
+bool xen_set_default_idle(void)
+{
+	bool ret = !!x86_idle;
+
+	x86_idle = default_idle;
+
+	return ret;
+}
+#endif
+
+struct cpumask cpus_stop_mask;
+
+void __noreturn stop_this_cpu(void *dummy)
+{
+	struct cpuinfo_x86 *c = this_cpu_ptr(&cpu_info);
+	unsigned int cpu = smp_processor_id();
+
+	local_irq_disable();
+
+	/*
+	 * Remove this CPU from the online mask and disable it
+	 * unconditionally. This might be redundant in case that the reboot
+	 * vector was handled late and stop_other_cpus() sent an NMI.
+	 *
+	 * According to SDM and APM NMIs can be accepted even after soft
+	 * disabling the local APIC.
+	 */
+	set_cpu_online(cpu, false);
+	disable_local_APIC();
+	mcheck_cpu_clear(c);
+
+	/*
+	 * Use wbinvd on processors that support SME. This provides support
+	 * for performing a successful kexec when going from SME inactive
+	 * to SME active (or vice-versa). The cache must be cleared so that
+	 * if there are entries with the same physical address, both with and
+	 * without the encryption bit, they don't race each other when flushed
+	 * and potentially end up with the wrong entry being committed to
+	 * memory.
+	 *
+	 * Test the CPUID bit directly because the machine might've cleared
+	 * X86_FEATURE_SME due to cmdline options.
+	 */
+	if (c->extended_cpuid_level >= 0x8000001f && (cpuid_eax(0x8000001f) & BIT(0)))
+		native_wbinvd();
+
+	/*
+	 * This brings a cache line back and dirties it, but
+	 * native_stop_other_cpus() will overwrite cpus_stop_mask after it
+	 * observed that all CPUs reported stop. This write will invalidate
+	 * the related cache line on this CPU.
+	 */
+	cpumask_clear_cpu(cpu, &cpus_stop_mask);
+
+	for (;;) {
+		/*
+		 * Use native_halt() so that memory contents don't change
+		 * (stack usage and variables) after possibly issuing the
+		 * native_wbinvd() above.
+		 */
+		native_halt();
+	}
+}
+
+/*
+ * AMD Erratum 400 aware idle routine. We handle it the same way as C3 power
+ * states (local apic timer and TSC stop).
+ *
+ * XXX this function is completely buggered vs RCU and tracing.
+ */
+static void amd_e400_idle(void)
+{
+	/*
+	 * We cannot use static_cpu_has_bug() here because X86_BUG_AMD_APIC_C1E
+	 * gets set after static_cpu_has() places have been converted via
+	 * alternatives.
+	 */
+	if (!boot_cpu_has_bug(X86_BUG_AMD_APIC_C1E)) {
+		default_idle();
+		return;
+	}
+
+	tick_broadcast_enter();
+
+	default_idle();
+
+	/*
+	 * The switch back from broadcast mode needs to be called with
+	 * interrupts disabled.
+	 */
+	raw_local_irq_disable();
+	tick_broadcast_exit();
+	raw_local_irq_enable();
+}
+
+/*
+ * Prefer MWAIT over HALT if MWAIT is supported, MWAIT_CPUID leaf
+ * exists and whenever MONITOR/MWAIT extensions are present there is at
+ * least one C1 substate.
+ *
+ * Do not prefer MWAIT if MONITOR instruction has a bug or idle=nomwait
+ * is passed to kernel commandline parameter.
+ */
+static int prefer_mwait_c1_over_halt(const struct cpuinfo_x86 *c)
+{
+	u32 eax, ebx, ecx, edx;
+
+	/* User has disallowed the use of MWAIT. Fallback to HALT */
+	if (boot_option_idle_override == IDLE_NOMWAIT)
+		return 0;
+
+	/* MWAIT is not supported on this platform. Fallback to HALT */
+	if (!cpu_has(c, X86_FEATURE_MWAIT))
+		return 0;
+
+	/* Monitor has a bug. Fallback to HALT */
+	if (boot_cpu_has_bug(X86_BUG_MONITOR))
+		return 0;
+
+	cpuid(CPUID_MWAIT_LEAF, &eax, &ebx, &ecx, &edx);
+
+	/*
+	 * If MWAIT extensions are not available, it is safe to use MWAIT
+	 * with EAX=0, ECX=0.
+	 */
+	if (!(ecx & CPUID5_ECX_EXTENSIONS_SUPPORTED))
+		return 1;
+
+	/*
+	 * If MWAIT extensions are available, there should be at least one
+	 * MWAIT C1 substate present.
+	 */
+	return (edx & MWAIT_C1_SUBSTATE_MASK);
+}
+
+/*
+ * MONITOR/MWAIT with no hints, used for default C1 state. This invokes MWAIT
+ * with interrupts enabled and no flags, which is backwards compatible with the
+ * original MWAIT implementation.
+ */
+static __cpuidle void mwait_idle(void)
+{
+	if (!current_set_polling_and_test()) {
+		if (this_cpu_has(X86_BUG_CLFLUSH_MONITOR)) {
+			mb(); /* quirk */
+			clflush((void *)&current_thread_info()->flags);
+			mb(); /* quirk */
+		}
+
+		__monitor((void *)&current_thread_info()->flags, 0, 0);
+		if (!need_resched())
+			__sti_mwait(0, 0);
+		else
+			raw_local_irq_enable();
+	} else {
+		raw_local_irq_enable();
+	}
+	__current_clr_polling();
+}
+
+void select_idle_routine(const struct cpuinfo_x86 *c)
+{
+#ifdef CONFIG_SMP
+	if (boot_option_idle_override == IDLE_POLL && smp_num_siblings > 1)
+		pr_warn_once("WARNING: polling idle and HT enabled, performance may degrade\n");
+#endif
+	if (x86_idle || boot_option_idle_override == IDLE_POLL)
+		return;
+
+	if (boot_cpu_has_bug(X86_BUG_AMD_E400)) {
+		pr_info("using AMD E400 aware idle routine\n");
+		x86_idle = amd_e400_idle;
+	} else if (prefer_mwait_c1_over_halt(c)) {
+		pr_info("using mwait in idle threads\n");
+		x86_idle = mwait_idle;
+	} else if (cpu_feature_enabled(X86_FEATURE_TDX_GUEST)) {
+		pr_info("using TDX aware idle routine\n");
+		x86_idle = tdx_safe_halt;
+	} else
+		x86_idle = default_idle;
+}
+
+void amd_e400_c1e_apic_setup(void)
+{
+	if (boot_cpu_has_bug(X86_BUG_AMD_APIC_C1E)) {
+		pr_info("Switch to broadcast mode on CPU%d\n", smp_processor_id());
+		local_irq_disable();
+		tick_broadcast_force();
+		local_irq_enable();
+	}
+}
+
+void __init arch_post_acpi_subsys_init(void)
+{
+	u32 lo, hi;
+
+	if (!boot_cpu_has_bug(X86_BUG_AMD_E400))
+		return;
+
+	/*
+	 * AMD E400 detection needs to happen after ACPI has been enabled. If
+	 * the machine is affected K8_INTP_C1E_ACTIVE_MASK bits are set in
+	 * MSR_K8_INT_PENDING_MSG.
+	 */
+	rdmsr(MSR_K8_INT_PENDING_MSG, lo, hi);
+	if (!(lo & K8_INTP_C1E_ACTIVE_MASK))
+		return;
+
+	boot_cpu_set_bug(X86_BUG_AMD_APIC_C1E);
+
+	if (!boot_cpu_has(X86_FEATURE_NONSTOP_TSC))
+		mark_tsc_unstable("TSC halt in AMD C1E");
+	pr_info("System has AMD C1E enabled\n");
+}
+
+static int __init idle_setup(char *str)
+{
+	if (!str)
+		return -EINVAL;
+
+	if (!strcmp(str, "poll")) {
+		pr_info("using polling idle threads\n");
+		boot_option_idle_override = IDLE_POLL;
+		cpu_idle_poll_ctrl(true);
+	} else if (!strcmp(str, "halt")) {
+		/*
+		 * When the boot option of idle=halt is added, halt is
+		 * forced to be used for CPU idle. In such case CPU C2/C3
+		 * won't be used again.
+		 * To continue to load the CPU idle driver, don't touch
+		 * the boot_option_idle_override.
+		 */
+		x86_idle = default_idle;
+		boot_option_idle_override = IDLE_HALT;
+	} else if (!strcmp(str, "nomwait")) {
+		/*
+		 * If the boot option of "idle=nomwait" is added,
+		 * it means that mwait will be disabled for CPU C1/C2/C3
+		 * states.
+		 */
+		boot_option_idle_override = IDLE_NOMWAIT;
+	} else
+		return -1;
+
+	return 0;
+}
+early_param("idle", idle_setup);
+
+unsigned long arch_align_stack(unsigned long sp)
+{
+	if (!(current->personality & ADDR_NO_RANDOMIZE) && randomize_va_space)
+		sp -= prandom_u32_max(8192);
+	return sp & ~0xf;
+}
+
+unsigned long arch_randomize_brk(struct mm_struct *mm)
+{
+	return randomize_page(mm->brk, 0x02000000);
+}
+
+/*
+ * Called from fs/proc with a reference on @p to find the function
+ * which called into schedule(). This needs to be done carefully
+ * because the task might wake up and we might look at a stack
+ * changing under us.
+ */
+unsigned long __get_wchan(struct task_struct *p)
+{
+	struct unwind_state state;
+	unsigned long addr = 0;
+
+	if (!try_get_task_stack(p))
+		return 0;
+
+	for (unwind_start(&state, p, NULL, NULL); !unwind_done(&state);
+	     unwind_next_frame(&state)) {
+		addr = unwind_get_return_address(&state);
+		if (!addr)
+			break;
+		if (in_sched_functions(addr))
+			continue;
+		break;
+	}
+
+	put_task_stack(p);
+
+	return addr;
+}
+
+long do_arch_prctl_common(int option, unsigned long arg2)
+{
+	switch (option) {
+	case ARCH_GET_CPUID:
+		return get_cpuid_mode();
+	case ARCH_SET_CPUID:
+		return set_cpuid_mode(arg2);
+	case ARCH_GET_XCOMP_SUPP:
+	case ARCH_GET_XCOMP_PERM:
+	case ARCH_REQ_XCOMP_PERM:
+	case ARCH_GET_XCOMP_GUEST_PERM:
+	case ARCH_REQ_XCOMP_GUEST_PERM:
+		return fpu_xstate_prctl(option, arg2);
+	}
+
+	return -EINVAL;
+}