https://github.com/torvalds/linux
Tip revision: 32346491ddf24599decca06190ebca03ff9de7f8 authored by Linus Torvalds on 10 July 2022, 21:40:51 UTC
Linux 5.19-rc6
Linux 5.19-rc6
Tip revision: 3234649
cpu.c
// SPDX-License-Identifier: GPL-2.0-only
/*
* Suspend support specific for i386/x86-64.
*
* Copyright (c) 2007 Rafael J. Wysocki <rjw@sisk.pl>
* Copyright (c) 2002 Pavel Machek <pavel@ucw.cz>
* Copyright (c) 2001 Patrick Mochel <mochel@osdl.org>
*/
#include <linux/suspend.h>
#include <linux/export.h>
#include <linux/smp.h>
#include <linux/perf_event.h>
#include <linux/tboot.h>
#include <linux/dmi.h>
#include <linux/pgtable.h>
#include <asm/proto.h>
#include <asm/mtrr.h>
#include <asm/page.h>
#include <asm/mce.h>
#include <asm/suspend.h>
#include <asm/fpu/api.h>
#include <asm/debugreg.h>
#include <asm/cpu.h>
#include <asm/mmu_context.h>
#include <asm/cpu_device_id.h>
#include <asm/microcode.h>
#ifdef CONFIG_X86_32
__visible unsigned long saved_context_ebx;
__visible unsigned long saved_context_esp, saved_context_ebp;
__visible unsigned long saved_context_esi, saved_context_edi;
__visible unsigned long saved_context_eflags;
#endif
struct saved_context saved_context;
static void msr_save_context(struct saved_context *ctxt)
{
struct saved_msr *msr = ctxt->saved_msrs.array;
struct saved_msr *end = msr + ctxt->saved_msrs.num;
while (msr < end) {
if (msr->valid)
rdmsrl(msr->info.msr_no, msr->info.reg.q);
msr++;
}
}
static void msr_restore_context(struct saved_context *ctxt)
{
struct saved_msr *msr = ctxt->saved_msrs.array;
struct saved_msr *end = msr + ctxt->saved_msrs.num;
while (msr < end) {
if (msr->valid)
wrmsrl(msr->info.msr_no, msr->info.reg.q);
msr++;
}
}
/**
* __save_processor_state() - Save CPU registers before creating a
* hibernation image and before restoring
* the memory state from it
* @ctxt: Structure to store the registers contents in.
*
* NOTE: If there is a CPU register the modification of which by the
* boot kernel (ie. the kernel used for loading the hibernation image)
* might affect the operations of the restored target kernel (ie. the one
* saved in the hibernation image), then its contents must be saved by this
* function. In other words, if kernel A is hibernated and different
* kernel B is used for loading the hibernation image into memory, the
* kernel A's __save_processor_state() function must save all registers
* needed by kernel A, so that it can operate correctly after the resume
* regardless of what kernel B does in the meantime.
*/
static void __save_processor_state(struct saved_context *ctxt)
{
#ifdef CONFIG_X86_32
mtrr_save_fixed_ranges(NULL);
#endif
kernel_fpu_begin();
/*
* descriptor tables
*/
store_idt(&ctxt->idt);
/*
* We save it here, but restore it only in the hibernate case.
* For ACPI S3 resume, this is loaded via 'early_gdt_desc' in 64-bit
* mode in "secondary_startup_64". In 32-bit mode it is done via
* 'pmode_gdt' in wakeup_start.
*/
ctxt->gdt_desc.size = GDT_SIZE - 1;
ctxt->gdt_desc.address = (unsigned long)get_cpu_gdt_rw(smp_processor_id());
store_tr(ctxt->tr);
/* XMM0..XMM15 should be handled by kernel_fpu_begin(). */
/*
* segment registers
*/
savesegment(gs, ctxt->gs);
#ifdef CONFIG_X86_64
savesegment(fs, ctxt->fs);
savesegment(ds, ctxt->ds);
savesegment(es, ctxt->es);
rdmsrl(MSR_FS_BASE, ctxt->fs_base);
rdmsrl(MSR_GS_BASE, ctxt->kernelmode_gs_base);
rdmsrl(MSR_KERNEL_GS_BASE, ctxt->usermode_gs_base);
mtrr_save_fixed_ranges(NULL);
rdmsrl(MSR_EFER, ctxt->efer);
#endif
/*
* control registers
*/
ctxt->cr0 = read_cr0();
ctxt->cr2 = read_cr2();
ctxt->cr3 = __read_cr3();
ctxt->cr4 = __read_cr4();
ctxt->misc_enable_saved = !rdmsrl_safe(MSR_IA32_MISC_ENABLE,
&ctxt->misc_enable);
msr_save_context(ctxt);
}
/* Needed by apm.c */
void save_processor_state(void)
{
__save_processor_state(&saved_context);
x86_platform.save_sched_clock_state();
}
#ifdef CONFIG_X86_32
EXPORT_SYMBOL(save_processor_state);
#endif
static void do_fpu_end(void)
{
/*
* Restore FPU regs if necessary.
*/
kernel_fpu_end();
}
static void fix_processor_context(void)
{
int cpu = smp_processor_id();
#ifdef CONFIG_X86_64
struct desc_struct *desc = get_cpu_gdt_rw(cpu);
tss_desc tss;
#endif
/*
* We need to reload TR, which requires that we change the
* GDT entry to indicate "available" first.
*
* XXX: This could probably all be replaced by a call to
* force_reload_TR().
*/
set_tss_desc(cpu, &get_cpu_entry_area(cpu)->tss.x86_tss);
#ifdef CONFIG_X86_64
memcpy(&tss, &desc[GDT_ENTRY_TSS], sizeof(tss_desc));
tss.type = 0x9; /* The available 64-bit TSS (see AMD vol 2, pg 91 */
write_gdt_entry(desc, GDT_ENTRY_TSS, &tss, DESC_TSS);
syscall_init(); /* This sets MSR_*STAR and related */
#else
if (boot_cpu_has(X86_FEATURE_SEP))
enable_sep_cpu();
#endif
load_TR_desc(); /* This does ltr */
load_mm_ldt(current->active_mm); /* This does lldt */
initialize_tlbstate_and_flush();
fpu__resume_cpu();
/* The processor is back on the direct GDT, load back the fixmap */
load_fixmap_gdt(cpu);
}
/**
* __restore_processor_state() - Restore the contents of CPU registers saved
* by __save_processor_state()
* @ctxt: Structure to load the registers contents from.
*
* The asm code that gets us here will have restored a usable GDT, although
* it will be pointing to the wrong alias.
*/
static void notrace __restore_processor_state(struct saved_context *ctxt)
{
struct cpuinfo_x86 *c;
if (ctxt->misc_enable_saved)
wrmsrl(MSR_IA32_MISC_ENABLE, ctxt->misc_enable);
/*
* control registers
*/
/* cr4 was introduced in the Pentium CPU */
#ifdef CONFIG_X86_32
if (ctxt->cr4)
__write_cr4(ctxt->cr4);
#else
/* CONFIG X86_64 */
wrmsrl(MSR_EFER, ctxt->efer);
__write_cr4(ctxt->cr4);
#endif
write_cr3(ctxt->cr3);
write_cr2(ctxt->cr2);
write_cr0(ctxt->cr0);
/* Restore the IDT. */
load_idt(&ctxt->idt);
/*
* Just in case the asm code got us here with the SS, DS, or ES
* out of sync with the GDT, update them.
*/
loadsegment(ss, __KERNEL_DS);
loadsegment(ds, __USER_DS);
loadsegment(es, __USER_DS);
/*
* Restore percpu access. Percpu access can happen in exception
* handlers or in complicated helpers like load_gs_index().
*/
#ifdef CONFIG_X86_64
wrmsrl(MSR_GS_BASE, ctxt->kernelmode_gs_base);
#else
loadsegment(fs, __KERNEL_PERCPU);
#endif
/* Restore the TSS, RO GDT, LDT, and usermode-relevant MSRs. */
fix_processor_context();
/*
* Now that we have descriptor tables fully restored and working
* exception handling, restore the usermode segments.
*/
#ifdef CONFIG_X86_64
loadsegment(ds, ctxt->es);
loadsegment(es, ctxt->es);
loadsegment(fs, ctxt->fs);
load_gs_index(ctxt->gs);
/*
* Restore FSBASE and GSBASE after restoring the selectors, since
* restoring the selectors clobbers the bases. Keep in mind
* that MSR_KERNEL_GS_BASE is horribly misnamed.
*/
wrmsrl(MSR_FS_BASE, ctxt->fs_base);
wrmsrl(MSR_KERNEL_GS_BASE, ctxt->usermode_gs_base);
#else
loadsegment(gs, ctxt->gs);
#endif
do_fpu_end();
tsc_verify_tsc_adjust(true);
x86_platform.restore_sched_clock_state();
mtrr_bp_restore();
perf_restore_debug_store();
c = &cpu_data(smp_processor_id());
if (cpu_has(c, X86_FEATURE_MSR_IA32_FEAT_CTL))
init_ia32_feat_ctl(c);
microcode_bsp_resume();
/*
* This needs to happen after the microcode has been updated upon resume
* because some of the MSRs are "emulated" in microcode.
*/
msr_restore_context(ctxt);
}
/* Needed by apm.c */
void notrace restore_processor_state(void)
{
__restore_processor_state(&saved_context);
}
#ifdef CONFIG_X86_32
EXPORT_SYMBOL(restore_processor_state);
#endif
#if defined(CONFIG_HIBERNATION) && defined(CONFIG_HOTPLUG_CPU)
static void resume_play_dead(void)
{
play_dead_common();
tboot_shutdown(TB_SHUTDOWN_WFS);
hlt_play_dead();
}
int hibernate_resume_nonboot_cpu_disable(void)
{
void (*play_dead)(void) = smp_ops.play_dead;
int ret;
/*
* Ensure that MONITOR/MWAIT will not be used in the "play dead" loop
* during hibernate image restoration, because it is likely that the
* monitored address will be actually written to at that time and then
* the "dead" CPU will attempt to execute instructions again, but the
* address in its instruction pointer may not be possible to resolve
* any more at that point (the page tables used by it previously may
* have been overwritten by hibernate image data).
*
* First, make sure that we wake up all the potentially disabled SMT
* threads which have been initially brought up and then put into
* mwait/cpuidle sleep.
* Those will be put to proper (not interfering with hibernation
* resume) sleep afterwards, and the resumed kernel will decide itself
* what to do with them.
*/
ret = cpuhp_smt_enable();
if (ret)
return ret;
smp_ops.play_dead = resume_play_dead;
ret = freeze_secondary_cpus(0);
smp_ops.play_dead = play_dead;
return ret;
}
#endif
/*
* When bsp_check() is called in hibernate and suspend, cpu hotplug
* is disabled already. So it's unnecessary to handle race condition between
* cpumask query and cpu hotplug.
*/
static int bsp_check(void)
{
if (cpumask_first(cpu_online_mask) != 0) {
pr_warn("CPU0 is offline.\n");
return -ENODEV;
}
return 0;
}
static int bsp_pm_callback(struct notifier_block *nb, unsigned long action,
void *ptr)
{
int ret = 0;
switch (action) {
case PM_SUSPEND_PREPARE:
case PM_HIBERNATION_PREPARE:
ret = bsp_check();
break;
#ifdef CONFIG_DEBUG_HOTPLUG_CPU0
case PM_RESTORE_PREPARE:
/*
* When system resumes from hibernation, online CPU0 because
* 1. it's required for resume and
* 2. the CPU was online before hibernation
*/
if (!cpu_online(0))
_debug_hotplug_cpu(0, 1);
break;
case PM_POST_RESTORE:
/*
* When a resume really happens, this code won't be called.
*
* This code is called only when user space hibernation software
* prepares for snapshot device during boot time. So we just
* call _debug_hotplug_cpu() to restore to CPU0's state prior to
* preparing the snapshot device.
*
* This works for normal boot case in our CPU0 hotplug debug
* mode, i.e. CPU0 is offline and user mode hibernation
* software initializes during boot time.
*
* If CPU0 is online and user application accesses snapshot
* device after boot time, this will offline CPU0 and user may
* see different CPU0 state before and after accessing
* the snapshot device. But hopefully this is not a case when
* user debugging CPU0 hotplug. Even if users hit this case,
* they can easily online CPU0 back.
*
* To simplify this debug code, we only consider normal boot
* case. Otherwise we need to remember CPU0's state and restore
* to that state and resolve racy conditions etc.
*/
_debug_hotplug_cpu(0, 0);
break;
#endif
default:
break;
}
return notifier_from_errno(ret);
}
static int __init bsp_pm_check_init(void)
{
/*
* Set this bsp_pm_callback as lower priority than
* cpu_hotplug_pm_callback. So cpu_hotplug_pm_callback will be called
* earlier to disable cpu hotplug before bsp online check.
*/
pm_notifier(bsp_pm_callback, -INT_MAX);
return 0;
}
core_initcall(bsp_pm_check_init);
static int msr_build_context(const u32 *msr_id, const int num)
{
struct saved_msrs *saved_msrs = &saved_context.saved_msrs;
struct saved_msr *msr_array;
int total_num;
int i, j;
total_num = saved_msrs->num + num;
msr_array = kmalloc_array(total_num, sizeof(struct saved_msr), GFP_KERNEL);
if (!msr_array) {
pr_err("x86/pm: Can not allocate memory to save/restore MSRs during suspend.\n");
return -ENOMEM;
}
if (saved_msrs->array) {
/*
* Multiple callbacks can invoke this function, so copy any
* MSR save requests from previous invocations.
*/
memcpy(msr_array, saved_msrs->array,
sizeof(struct saved_msr) * saved_msrs->num);
kfree(saved_msrs->array);
}
for (i = saved_msrs->num, j = 0; i < total_num; i++, j++) {
u64 dummy;
msr_array[i].info.msr_no = msr_id[j];
msr_array[i].valid = !rdmsrl_safe(msr_id[j], &dummy);
msr_array[i].info.reg.q = 0;
}
saved_msrs->num = total_num;
saved_msrs->array = msr_array;
return 0;
}
/*
* The following sections are a quirk framework for problematic BIOSen:
* Sometimes MSRs are modified by the BIOSen after suspended to
* RAM, this might cause unexpected behavior after wakeup.
* Thus we save/restore these specified MSRs across suspend/resume
* in order to work around it.
*
* For any further problematic BIOSen/platforms,
* please add your own function similar to msr_initialize_bdw.
*/
static int msr_initialize_bdw(const struct dmi_system_id *d)
{
/* Add any extra MSR ids into this array. */
u32 bdw_msr_id[] = { MSR_IA32_THERM_CONTROL };
pr_info("x86/pm: %s detected, MSR saving is needed during suspending.\n", d->ident);
return msr_build_context(bdw_msr_id, ARRAY_SIZE(bdw_msr_id));
}
static const struct dmi_system_id msr_save_dmi_table[] = {
{
.callback = msr_initialize_bdw,
.ident = "BROADWELL BDX_EP",
.matches = {
DMI_MATCH(DMI_PRODUCT_NAME, "GRANTLEY"),
DMI_MATCH(DMI_PRODUCT_VERSION, "E63448-400"),
},
},
{}
};
static int msr_save_cpuid_features(const struct x86_cpu_id *c)
{
u32 cpuid_msr_id[] = {
MSR_AMD64_CPUID_FN_1,
};
pr_info("x86/pm: family %#hx cpu detected, MSR saving is needed during suspending.\n",
c->family);
return msr_build_context(cpuid_msr_id, ARRAY_SIZE(cpuid_msr_id));
}
static const struct x86_cpu_id msr_save_cpu_table[] = {
X86_MATCH_VENDOR_FAM(AMD, 0x15, &msr_save_cpuid_features),
X86_MATCH_VENDOR_FAM(AMD, 0x16, &msr_save_cpuid_features),
{}
};
typedef int (*pm_cpu_match_t)(const struct x86_cpu_id *);
static int pm_cpu_check(const struct x86_cpu_id *c)
{
const struct x86_cpu_id *m;
int ret = 0;
m = x86_match_cpu(msr_save_cpu_table);
if (m) {
pm_cpu_match_t fn;
fn = (pm_cpu_match_t)m->driver_data;
ret = fn(m);
}
return ret;
}
static void pm_save_spec_msr(void)
{
u32 spec_msr_id[] = {
MSR_IA32_SPEC_CTRL,
MSR_IA32_TSX_CTRL,
MSR_TSX_FORCE_ABORT,
MSR_IA32_MCU_OPT_CTRL,
MSR_AMD64_LS_CFG,
};
msr_build_context(spec_msr_id, ARRAY_SIZE(spec_msr_id));
}
static int pm_check_save_msr(void)
{
dmi_check_system(msr_save_dmi_table);
pm_cpu_check(msr_save_cpu_table);
pm_save_spec_msr();
return 0;
}
device_initcall(pm_check_save_msr);