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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-05-06 01:02:30 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-05-06 01:02:30 +0000
commit76cb841cb886eef6b3bee341a2266c76578724ad (patch)
treef5892e5ba6cc11949952a6ce4ecbe6d516d6ce58 /arch/x86/power
parentInitial commit. (diff)
downloadlinux-76cb841cb886eef6b3bee341a2266c76578724ad.tar.xz
linux-76cb841cb886eef6b3bee341a2266c76578724ad.zip
Adding upstream version 4.19.249.upstream/4.19.249
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'arch/x86/power')
-rw-r--r--arch/x86/power/Makefile10
-rw-r--r--arch/x86/power/cpu.c550
-rw-r--r--arch/x86/power/hibernate_32.c175
-rw-r--r--arch/x86/power/hibernate_64.c397
-rw-r--r--arch/x86/power/hibernate_asm_32.S85
-rw-r--r--arch/x86/power/hibernate_asm_64.S146
6 files changed, 1363 insertions, 0 deletions
diff --git a/arch/x86/power/Makefile b/arch/x86/power/Makefile
new file mode 100644
index 000000000..a47013895
--- /dev/null
+++ b/arch/x86/power/Makefile
@@ -0,0 +1,10 @@
+# SPDX-License-Identifier: GPL-2.0
+OBJECT_FILES_NON_STANDARD_hibernate_asm_$(BITS).o := y
+
+# __restore_processor_state() restores %gs after S3 resume and so should not
+# itself be stack-protected
+nostackp := $(call cc-option, -fno-stack-protector)
+CFLAGS_cpu.o := $(nostackp)
+
+obj-$(CONFIG_PM_SLEEP) += cpu.o
+obj-$(CONFIG_HIBERNATION) += hibernate_$(BITS).o hibernate_asm_$(BITS).o
diff --git a/arch/x86/power/cpu.c b/arch/x86/power/cpu.c
new file mode 100644
index 000000000..794824948
--- /dev/null
+++ b/arch/x86/power/cpu.c
@@ -0,0 +1,550 @@
+/*
+ * Suspend support specific for i386/x86-64.
+ *
+ * Distribute under GPLv2
+ *
+ * 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 <asm/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/internal.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
+ */
+#ifdef CONFIG_X86_32_LAZY_GS
+ savesegment(gs, ctxt->gs);
+#endif
+#ifdef CONFIG_X86_64
+ savesegment(gs, ctxt->gs);
+ 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();
+#ifdef CONFIG_X86_64
+ ctxt->cr8 = read_cr8();
+#endif
+ 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)
+{
+ 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_cr8(ctxt->cr8);
+ __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);
+ loadsegment(gs, __KERNEL_STACK_CANARY);
+#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);
+#elif defined(CONFIG_X86_32_LAZY_GS)
+ 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();
+
+ 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 = disable_nonboot_cpus();
+ 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 unnessary 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[] = {
+ {
+ .vendor = X86_VENDOR_AMD,
+ .family = 0x15,
+ .model = X86_MODEL_ANY,
+ .feature = X86_FEATURE_ANY,
+ .driver_data = (kernel_ulong_t)msr_save_cpuid_features,
+ },
+ {
+ .vendor = X86_VENDOR_AMD,
+ .family = 0x16,
+ .model = X86_MODEL_ANY,
+ .feature = X86_FEATURE_ANY,
+ .driver_data = (kernel_ulong_t)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);
diff --git a/arch/x86/power/hibernate_32.c b/arch/x86/power/hibernate_32.c
new file mode 100644
index 000000000..afc4ed7b1
--- /dev/null
+++ b/arch/x86/power/hibernate_32.c
@@ -0,0 +1,175 @@
+/*
+ * Hibernation support specific for i386 - temporary page tables
+ *
+ * Distribute under GPLv2
+ *
+ * Copyright (c) 2006 Rafael J. Wysocki <rjw@sisk.pl>
+ */
+
+#include <linux/gfp.h>
+#include <linux/suspend.h>
+#include <linux/bootmem.h>
+
+#include <asm/page.h>
+#include <asm/pgtable.h>
+#include <asm/mmzone.h>
+#include <asm/sections.h>
+
+/* Defined in hibernate_asm_32.S */
+extern int restore_image(void);
+
+/* Pointer to the temporary resume page tables */
+pgd_t *resume_pg_dir;
+
+/* The following three functions are based on the analogous code in
+ * arch/x86/mm/init_32.c
+ */
+
+/*
+ * Create a middle page table on a resume-safe page and put a pointer to it in
+ * the given global directory entry. This only returns the gd entry
+ * in non-PAE compilation mode, since the middle layer is folded.
+ */
+static pmd_t *resume_one_md_table_init(pgd_t *pgd)
+{
+ p4d_t *p4d;
+ pud_t *pud;
+ pmd_t *pmd_table;
+
+#ifdef CONFIG_X86_PAE
+ pmd_table = (pmd_t *)get_safe_page(GFP_ATOMIC);
+ if (!pmd_table)
+ return NULL;
+
+ set_pgd(pgd, __pgd(__pa(pmd_table) | _PAGE_PRESENT));
+ p4d = p4d_offset(pgd, 0);
+ pud = pud_offset(p4d, 0);
+
+ BUG_ON(pmd_table != pmd_offset(pud, 0));
+#else
+ p4d = p4d_offset(pgd, 0);
+ pud = pud_offset(p4d, 0);
+ pmd_table = pmd_offset(pud, 0);
+#endif
+
+ return pmd_table;
+}
+
+/*
+ * Create a page table on a resume-safe page and place a pointer to it in
+ * a middle page directory entry.
+ */
+static pte_t *resume_one_page_table_init(pmd_t *pmd)
+{
+ if (pmd_none(*pmd)) {
+ pte_t *page_table = (pte_t *)get_safe_page(GFP_ATOMIC);
+ if (!page_table)
+ return NULL;
+
+ set_pmd(pmd, __pmd(__pa(page_table) | _PAGE_TABLE));
+
+ BUG_ON(page_table != pte_offset_kernel(pmd, 0));
+
+ return page_table;
+ }
+
+ return pte_offset_kernel(pmd, 0);
+}
+
+/*
+ * This maps the physical memory to kernel virtual address space, a total
+ * of max_low_pfn pages, by creating page tables starting from address
+ * PAGE_OFFSET. The page tables are allocated out of resume-safe pages.
+ */
+static int resume_physical_mapping_init(pgd_t *pgd_base)
+{
+ unsigned long pfn;
+ pgd_t *pgd;
+ pmd_t *pmd;
+ pte_t *pte;
+ int pgd_idx, pmd_idx;
+
+ pgd_idx = pgd_index(PAGE_OFFSET);
+ pgd = pgd_base + pgd_idx;
+ pfn = 0;
+
+ for (; pgd_idx < PTRS_PER_PGD; pgd++, pgd_idx++) {
+ pmd = resume_one_md_table_init(pgd);
+ if (!pmd)
+ return -ENOMEM;
+
+ if (pfn >= max_low_pfn)
+ continue;
+
+ for (pmd_idx = 0; pmd_idx < PTRS_PER_PMD; pmd++, pmd_idx++) {
+ if (pfn >= max_low_pfn)
+ break;
+
+ /* Map with big pages if possible, otherwise create
+ * normal page tables.
+ * NOTE: We can mark everything as executable here
+ */
+ if (boot_cpu_has(X86_FEATURE_PSE)) {
+ set_pmd(pmd, pfn_pmd(pfn, PAGE_KERNEL_LARGE_EXEC));
+ pfn += PTRS_PER_PTE;
+ } else {
+ pte_t *max_pte;
+
+ pte = resume_one_page_table_init(pmd);
+ if (!pte)
+ return -ENOMEM;
+
+ max_pte = pte + PTRS_PER_PTE;
+ for (; pte < max_pte; pte++, pfn++) {
+ if (pfn >= max_low_pfn)
+ break;
+
+ set_pte(pte, pfn_pte(pfn, PAGE_KERNEL_EXEC));
+ }
+ }
+ }
+ }
+
+ return 0;
+}
+
+static inline void resume_init_first_level_page_table(pgd_t *pg_dir)
+{
+#ifdef CONFIG_X86_PAE
+ int i;
+
+ /* Init entries of the first-level page table to the zero page */
+ for (i = 0; i < PTRS_PER_PGD; i++)
+ set_pgd(pg_dir + i,
+ __pgd(__pa(empty_zero_page) | _PAGE_PRESENT));
+#endif
+}
+
+asmlinkage int swsusp_arch_resume(void)
+{
+ int error;
+
+ resume_pg_dir = (pgd_t *)get_safe_page(GFP_ATOMIC);
+ if (!resume_pg_dir)
+ return -ENOMEM;
+
+ resume_init_first_level_page_table(resume_pg_dir);
+ error = resume_physical_mapping_init(resume_pg_dir);
+ if (error)
+ return error;
+
+ /* We have got enough memory and from now on we cannot recover */
+ restore_image();
+ return 0;
+}
+
+/*
+ * pfn_is_nosave - check if given pfn is in the 'nosave' section
+ */
+
+int pfn_is_nosave(unsigned long pfn)
+{
+ unsigned long nosave_begin_pfn = __pa_symbol(&__nosave_begin) >> PAGE_SHIFT;
+ unsigned long nosave_end_pfn = PAGE_ALIGN(__pa_symbol(&__nosave_end)) >> PAGE_SHIFT;
+ return (pfn >= nosave_begin_pfn) && (pfn < nosave_end_pfn);
+}
diff --git a/arch/x86/power/hibernate_64.c b/arch/x86/power/hibernate_64.c
new file mode 100644
index 000000000..6c3ec193a
--- /dev/null
+++ b/arch/x86/power/hibernate_64.c
@@ -0,0 +1,397 @@
+/*
+ * Hibernation support for x86-64
+ *
+ * Distribute under GPLv2
+ *
+ * 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/gfp.h>
+#include <linux/smp.h>
+#include <linux/suspend.h>
+#include <linux/scatterlist.h>
+#include <linux/kdebug.h>
+#include <linux/cpu.h>
+
+#include <crypto/hash.h>
+
+#include <asm/e820/api.h>
+#include <asm/init.h>
+#include <asm/proto.h>
+#include <asm/page.h>
+#include <asm/pgtable.h>
+#include <asm/mtrr.h>
+#include <asm/sections.h>
+#include <asm/suspend.h>
+#include <asm/tlbflush.h>
+
+/* Defined in hibernate_asm_64.S */
+extern asmlinkage __visible int restore_image(void);
+
+/*
+ * Address to jump to in the last phase of restore in order to get to the image
+ * kernel's text (this value is passed in the image header).
+ */
+unsigned long restore_jump_address __visible;
+unsigned long jump_address_phys;
+
+/*
+ * Value of the cr3 register from before the hibernation (this value is passed
+ * in the image header).
+ */
+unsigned long restore_cr3 __visible;
+
+unsigned long temp_level4_pgt __visible;
+
+unsigned long relocated_restore_code __visible;
+
+static int set_up_temporary_text_mapping(pgd_t *pgd)
+{
+ pmd_t *pmd;
+ pud_t *pud;
+ p4d_t *p4d = NULL;
+ pgprot_t pgtable_prot = __pgprot(_KERNPG_TABLE);
+ pgprot_t pmd_text_prot = __pgprot(__PAGE_KERNEL_LARGE_EXEC);
+
+ /* Filter out unsupported __PAGE_KERNEL* bits: */
+ pgprot_val(pmd_text_prot) &= __default_kernel_pte_mask;
+ pgprot_val(pgtable_prot) &= __default_kernel_pte_mask;
+
+ /*
+ * The new mapping only has to cover the page containing the image
+ * kernel's entry point (jump_address_phys), because the switch over to
+ * it is carried out by relocated code running from a page allocated
+ * specifically for this purpose and covered by the identity mapping, so
+ * the temporary kernel text mapping is only needed for the final jump.
+ * Moreover, in that mapping the virtual address of the image kernel's
+ * entry point must be the same as its virtual address in the image
+ * kernel (restore_jump_address), so the image kernel's
+ * restore_registers() code doesn't find itself in a different area of
+ * the virtual address space after switching over to the original page
+ * tables used by the image kernel.
+ */
+
+ if (pgtable_l5_enabled()) {
+ p4d = (p4d_t *)get_safe_page(GFP_ATOMIC);
+ if (!p4d)
+ return -ENOMEM;
+ }
+
+ pud = (pud_t *)get_safe_page(GFP_ATOMIC);
+ if (!pud)
+ return -ENOMEM;
+
+ pmd = (pmd_t *)get_safe_page(GFP_ATOMIC);
+ if (!pmd)
+ return -ENOMEM;
+
+ set_pmd(pmd + pmd_index(restore_jump_address),
+ __pmd((jump_address_phys & PMD_MASK) | pgprot_val(pmd_text_prot)));
+ set_pud(pud + pud_index(restore_jump_address),
+ __pud(__pa(pmd) | pgprot_val(pgtable_prot)));
+ if (p4d) {
+ p4d_t new_p4d = __p4d(__pa(pud) | pgprot_val(pgtable_prot));
+ pgd_t new_pgd = __pgd(__pa(p4d) | pgprot_val(pgtable_prot));
+
+ set_p4d(p4d + p4d_index(restore_jump_address), new_p4d);
+ set_pgd(pgd + pgd_index(restore_jump_address), new_pgd);
+ } else {
+ /* No p4d for 4-level paging: point the pgd to the pud page table */
+ pgd_t new_pgd = __pgd(__pa(pud) | pgprot_val(pgtable_prot));
+ set_pgd(pgd + pgd_index(restore_jump_address), new_pgd);
+ }
+
+ return 0;
+}
+
+static void *alloc_pgt_page(void *context)
+{
+ return (void *)get_safe_page(GFP_ATOMIC);
+}
+
+static int set_up_temporary_mappings(void)
+{
+ struct x86_mapping_info info = {
+ .alloc_pgt_page = alloc_pgt_page,
+ .page_flag = __PAGE_KERNEL_LARGE_EXEC,
+ .offset = __PAGE_OFFSET,
+ };
+ unsigned long mstart, mend;
+ pgd_t *pgd;
+ int result;
+ int i;
+
+ pgd = (pgd_t *)get_safe_page(GFP_ATOMIC);
+ if (!pgd)
+ return -ENOMEM;
+
+ /* Prepare a temporary mapping for the kernel text */
+ result = set_up_temporary_text_mapping(pgd);
+ if (result)
+ return result;
+
+ /* Set up the direct mapping from scratch */
+ for (i = 0; i < nr_pfn_mapped; i++) {
+ mstart = pfn_mapped[i].start << PAGE_SHIFT;
+ mend = pfn_mapped[i].end << PAGE_SHIFT;
+
+ result = kernel_ident_mapping_init(&info, pgd, mstart, mend);
+ if (result)
+ return result;
+ }
+
+ temp_level4_pgt = __pa(pgd);
+ return 0;
+}
+
+static int relocate_restore_code(void)
+{
+ pgd_t *pgd;
+ p4d_t *p4d;
+ pud_t *pud;
+ pmd_t *pmd;
+ pte_t *pte;
+
+ relocated_restore_code = get_safe_page(GFP_ATOMIC);
+ if (!relocated_restore_code)
+ return -ENOMEM;
+
+ memcpy((void *)relocated_restore_code, core_restore_code, PAGE_SIZE);
+
+ /* Make the page containing the relocated code executable */
+ pgd = (pgd_t *)__va(read_cr3_pa()) +
+ pgd_index(relocated_restore_code);
+ p4d = p4d_offset(pgd, relocated_restore_code);
+ if (p4d_large(*p4d)) {
+ set_p4d(p4d, __p4d(p4d_val(*p4d) & ~_PAGE_NX));
+ goto out;
+ }
+ pud = pud_offset(p4d, relocated_restore_code);
+ if (pud_large(*pud)) {
+ set_pud(pud, __pud(pud_val(*pud) & ~_PAGE_NX));
+ goto out;
+ }
+ pmd = pmd_offset(pud, relocated_restore_code);
+ if (pmd_large(*pmd)) {
+ set_pmd(pmd, __pmd(pmd_val(*pmd) & ~_PAGE_NX));
+ goto out;
+ }
+ pte = pte_offset_kernel(pmd, relocated_restore_code);
+ set_pte(pte, __pte(pte_val(*pte) & ~_PAGE_NX));
+out:
+ __flush_tlb_all();
+ return 0;
+}
+
+asmlinkage int swsusp_arch_resume(void)
+{
+ int error;
+
+ /* We have got enough memory and from now on we cannot recover */
+ error = set_up_temporary_mappings();
+ if (error)
+ return error;
+
+ error = relocate_restore_code();
+ if (error)
+ return error;
+
+ restore_image();
+ return 0;
+}
+
+/*
+ * pfn_is_nosave - check if given pfn is in the 'nosave' section
+ */
+
+int pfn_is_nosave(unsigned long pfn)
+{
+ unsigned long nosave_begin_pfn = __pa_symbol(&__nosave_begin) >> PAGE_SHIFT;
+ unsigned long nosave_end_pfn = PAGE_ALIGN(__pa_symbol(&__nosave_end)) >> PAGE_SHIFT;
+ return (pfn >= nosave_begin_pfn) && (pfn < nosave_end_pfn);
+}
+
+#define MD5_DIGEST_SIZE 16
+
+struct restore_data_record {
+ unsigned long jump_address;
+ unsigned long jump_address_phys;
+ unsigned long cr3;
+ unsigned long magic;
+ u8 e820_digest[MD5_DIGEST_SIZE];
+};
+
+#define RESTORE_MAGIC 0x23456789ABCDEF01UL
+
+#if IS_BUILTIN(CONFIG_CRYPTO_MD5)
+/**
+ * get_e820_md5 - calculate md5 according to given e820 table
+ *
+ * @table: the e820 table to be calculated
+ * @buf: the md5 result to be stored to
+ */
+static int get_e820_md5(struct e820_table *table, void *buf)
+{
+ struct crypto_shash *tfm;
+ struct shash_desc *desc;
+ int size;
+ int ret = 0;
+
+ tfm = crypto_alloc_shash("md5", 0, 0);
+ if (IS_ERR(tfm))
+ return -ENOMEM;
+
+ desc = kmalloc(sizeof(struct shash_desc) + crypto_shash_descsize(tfm),
+ GFP_KERNEL);
+ if (!desc) {
+ ret = -ENOMEM;
+ goto free_tfm;
+ }
+
+ desc->tfm = tfm;
+ desc->flags = 0;
+
+ size = offsetof(struct e820_table, entries) +
+ sizeof(struct e820_entry) * table->nr_entries;
+
+ if (crypto_shash_digest(desc, (u8 *)table, size, buf))
+ ret = -EINVAL;
+
+ kzfree(desc);
+
+free_tfm:
+ crypto_free_shash(tfm);
+ return ret;
+}
+
+static int hibernation_e820_save(void *buf)
+{
+ return get_e820_md5(e820_table_firmware, buf);
+}
+
+static bool hibernation_e820_mismatch(void *buf)
+{
+ int ret;
+ u8 result[MD5_DIGEST_SIZE];
+
+ memset(result, 0, MD5_DIGEST_SIZE);
+ /* If there is no digest in suspend kernel, let it go. */
+ if (!memcmp(result, buf, MD5_DIGEST_SIZE))
+ return false;
+
+ ret = get_e820_md5(e820_table_firmware, result);
+ if (ret)
+ return true;
+
+ return memcmp(result, buf, MD5_DIGEST_SIZE) ? true : false;
+}
+#else
+static int hibernation_e820_save(void *buf)
+{
+ return 0;
+}
+
+static bool hibernation_e820_mismatch(void *buf)
+{
+ /* If md5 is not builtin for restore kernel, let it go. */
+ return false;
+}
+#endif
+
+/**
+ * arch_hibernation_header_save - populate the architecture specific part
+ * of a hibernation image header
+ * @addr: address to save the data at
+ */
+int arch_hibernation_header_save(void *addr, unsigned int max_size)
+{
+ struct restore_data_record *rdr = addr;
+
+ if (max_size < sizeof(struct restore_data_record))
+ return -EOVERFLOW;
+ rdr->jump_address = (unsigned long)restore_registers;
+ rdr->jump_address_phys = __pa_symbol(restore_registers);
+
+ /*
+ * The restore code fixes up CR3 and CR4 in the following sequence:
+ *
+ * [in hibernation asm]
+ * 1. CR3 <= temporary page tables
+ * 2. CR4 <= mmu_cr4_features (from the kernel that restores us)
+ * 3. CR3 <= rdr->cr3
+ * 4. CR4 <= mmu_cr4_features (from us, i.e. the image kernel)
+ * [in restore_processor_state()]
+ * 5. CR4 <= saved CR4
+ * 6. CR3 <= saved CR3
+ *
+ * Our mmu_cr4_features has CR4.PCIDE=0, and toggling
+ * CR4.PCIDE while CR3's PCID bits are nonzero is illegal, so
+ * rdr->cr3 needs to point to valid page tables but must not
+ * have any of the PCID bits set.
+ */
+ rdr->cr3 = restore_cr3 & ~CR3_PCID_MASK;
+
+ rdr->magic = RESTORE_MAGIC;
+
+ return hibernation_e820_save(rdr->e820_digest);
+}
+
+/**
+ * arch_hibernation_header_restore - read the architecture specific data
+ * from the hibernation image header
+ * @addr: address to read the data from
+ */
+int arch_hibernation_header_restore(void *addr)
+{
+ struct restore_data_record *rdr = addr;
+
+ restore_jump_address = rdr->jump_address;
+ jump_address_phys = rdr->jump_address_phys;
+ restore_cr3 = rdr->cr3;
+
+ if (rdr->magic != RESTORE_MAGIC) {
+ pr_crit("Unrecognized hibernate image header format!\n");
+ return -EINVAL;
+ }
+
+ if (hibernation_e820_mismatch(rdr->e820_digest)) {
+ pr_crit("Hibernate inconsistent memory map detected!\n");
+ return -ENODEV;
+ }
+
+ return 0;
+}
+
+int arch_resume_nosmt(void)
+{
+ int ret = 0;
+ /*
+ * We reached this while coming out of hibernation. This means
+ * that SMT siblings are sleeping in hlt, as mwait is not safe
+ * against control transition during resume (see comment in
+ * hibernate_resume_nonboot_cpu_disable()).
+ *
+ * If the resumed kernel has SMT disabled, we have to take all the
+ * SMT siblings out of hlt, and offline them again so that they
+ * end up in mwait proper.
+ *
+ * Called with hotplug disabled.
+ */
+ cpu_hotplug_enable();
+ if (cpu_smt_control == CPU_SMT_DISABLED ||
+ cpu_smt_control == CPU_SMT_FORCE_DISABLED) {
+ enum cpuhp_smt_control old = cpu_smt_control;
+
+ ret = cpuhp_smt_enable();
+ if (ret)
+ goto out;
+ ret = cpuhp_smt_disable(old);
+ if (ret)
+ goto out;
+ }
+out:
+ cpu_hotplug_disable();
+ return ret;
+}
diff --git a/arch/x86/power/hibernate_asm_32.S b/arch/x86/power/hibernate_asm_32.S
new file mode 100644
index 000000000..6e56815e1
--- /dev/null
+++ b/arch/x86/power/hibernate_asm_32.S
@@ -0,0 +1,85 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * This may not use any stack, nor any variable that is not "NoSave":
+ *
+ * Its rewriting one kernel image with another. What is stack in "old"
+ * image could very well be data page in "new" image, and overwriting
+ * your own stack under you is bad idea.
+ */
+
+#include <linux/linkage.h>
+#include <asm/segment.h>
+#include <asm/page_types.h>
+#include <asm/asm-offsets.h>
+#include <asm/processor-flags.h>
+
+.text
+
+ENTRY(swsusp_arch_suspend)
+ movl %esp, saved_context_esp
+ movl %ebx, saved_context_ebx
+ movl %ebp, saved_context_ebp
+ movl %esi, saved_context_esi
+ movl %edi, saved_context_edi
+ pushfl
+ popl saved_context_eflags
+
+ call swsusp_save
+ ret
+
+ENTRY(restore_image)
+ movl mmu_cr4_features, %ecx
+ movl resume_pg_dir, %eax
+ subl $__PAGE_OFFSET, %eax
+ movl %eax, %cr3
+
+ jecxz 1f # cr4 Pentium and higher, skip if zero
+ andl $~(X86_CR4_PGE), %ecx
+ movl %ecx, %cr4; # turn off PGE
+ movl %cr3, %eax; # flush TLB
+ movl %eax, %cr3
+1:
+ movl restore_pblist, %edx
+ .p2align 4,,7
+
+copy_loop:
+ testl %edx, %edx
+ jz done
+
+ movl pbe_address(%edx), %esi
+ movl pbe_orig_address(%edx), %edi
+
+ movl $1024, %ecx
+ rep
+ movsl
+
+ movl pbe_next(%edx), %edx
+ jmp copy_loop
+ .p2align 4,,7
+
+done:
+ /* go back to the original page tables */
+ movl $swapper_pg_dir, %eax
+ subl $__PAGE_OFFSET, %eax
+ movl %eax, %cr3
+ movl mmu_cr4_features, %ecx
+ jecxz 1f # cr4 Pentium and higher, skip if zero
+ movl %ecx, %cr4; # turn PGE back on
+1:
+
+ movl saved_context_esp, %esp
+ movl saved_context_ebp, %ebp
+ movl saved_context_ebx, %ebx
+ movl saved_context_esi, %esi
+ movl saved_context_edi, %edi
+
+ pushl saved_context_eflags
+ popfl
+
+ /* Saved in save_processor_state. */
+ movl $saved_context, %eax
+ lgdt saved_context_gdt_desc(%eax)
+
+ xorl %eax, %eax
+
+ ret
diff --git a/arch/x86/power/hibernate_asm_64.S b/arch/x86/power/hibernate_asm_64.S
new file mode 100644
index 000000000..fd369a6e9
--- /dev/null
+++ b/arch/x86/power/hibernate_asm_64.S
@@ -0,0 +1,146 @@
+/*
+ * Hibernation support for x86-64
+ *
+ * Distribute under GPLv2.
+ *
+ * Copyright 2007 Rafael J. Wysocki <rjw@sisk.pl>
+ * Copyright 2005 Andi Kleen <ak@suse.de>
+ * Copyright 2004 Pavel Machek <pavel@suse.cz>
+ *
+ * swsusp_arch_resume must not use any stack or any nonlocal variables while
+ * copying pages:
+ *
+ * Its rewriting one kernel image with another. What is stack in "old"
+ * image could very well be data page in "new" image, and overwriting
+ * your own stack under you is bad idea.
+ */
+
+ .text
+#include <linux/linkage.h>
+#include <asm/segment.h>
+#include <asm/page_types.h>
+#include <asm/asm-offsets.h>
+#include <asm/processor-flags.h>
+#include <asm/frame.h>
+
+ENTRY(swsusp_arch_suspend)
+ movq $saved_context, %rax
+ movq %rsp, pt_regs_sp(%rax)
+ movq %rbp, pt_regs_bp(%rax)
+ movq %rsi, pt_regs_si(%rax)
+ movq %rdi, pt_regs_di(%rax)
+ movq %rbx, pt_regs_bx(%rax)
+ movq %rcx, pt_regs_cx(%rax)
+ movq %rdx, pt_regs_dx(%rax)
+ movq %r8, pt_regs_r8(%rax)
+ movq %r9, pt_regs_r9(%rax)
+ movq %r10, pt_regs_r10(%rax)
+ movq %r11, pt_regs_r11(%rax)
+ movq %r12, pt_regs_r12(%rax)
+ movq %r13, pt_regs_r13(%rax)
+ movq %r14, pt_regs_r14(%rax)
+ movq %r15, pt_regs_r15(%rax)
+ pushfq
+ popq pt_regs_flags(%rax)
+
+ /* save cr3 */
+ movq %cr3, %rax
+ movq %rax, restore_cr3(%rip)
+
+ FRAME_BEGIN
+ call swsusp_save
+ FRAME_END
+ ret
+ENDPROC(swsusp_arch_suspend)
+
+ENTRY(restore_image)
+ /* prepare to jump to the image kernel */
+ movq restore_jump_address(%rip), %r8
+ movq restore_cr3(%rip), %r9
+
+ /* prepare to switch to temporary page tables */
+ movq temp_level4_pgt(%rip), %rax
+ movq mmu_cr4_features(%rip), %rbx
+
+ /* prepare to copy image data to their original locations */
+ movq restore_pblist(%rip), %rdx
+
+ /* jump to relocated restore code */
+ movq relocated_restore_code(%rip), %rcx
+ jmpq *%rcx
+
+ /* code below has been relocated to a safe page */
+ENTRY(core_restore_code)
+ /* switch to temporary page tables */
+ movq %rax, %cr3
+ /* flush TLB */
+ movq %rbx, %rcx
+ andq $~(X86_CR4_PGE), %rcx
+ movq %rcx, %cr4; # turn off PGE
+ movq %cr3, %rcx; # flush TLB
+ movq %rcx, %cr3;
+ movq %rbx, %cr4; # turn PGE back on
+.Lloop:
+ testq %rdx, %rdx
+ jz .Ldone
+
+ /* get addresses from the pbe and copy the page */
+ movq pbe_address(%rdx), %rsi
+ movq pbe_orig_address(%rdx), %rdi
+ movq $(PAGE_SIZE >> 3), %rcx
+ rep
+ movsq
+
+ /* progress to the next pbe */
+ movq pbe_next(%rdx), %rdx
+ jmp .Lloop
+
+.Ldone:
+ /* jump to the restore_registers address from the image header */
+ jmpq *%r8
+
+ /* code below belongs to the image kernel */
+ .align PAGE_SIZE
+ENTRY(restore_registers)
+ /* go back to the original page tables */
+ movq %r9, %cr3
+
+ /* Flush TLB, including "global" things (vmalloc) */
+ movq mmu_cr4_features(%rip), %rax
+ movq %rax, %rdx
+ andq $~(X86_CR4_PGE), %rdx
+ movq %rdx, %cr4; # turn off PGE
+ movq %cr3, %rcx; # flush TLB
+ movq %rcx, %cr3
+ movq %rax, %cr4; # turn PGE back on
+
+ /* We don't restore %rax, it must be 0 anyway */
+ movq $saved_context, %rax
+ movq pt_regs_sp(%rax), %rsp
+ movq pt_regs_bp(%rax), %rbp
+ movq pt_regs_si(%rax), %rsi
+ movq pt_regs_di(%rax), %rdi
+ movq pt_regs_bx(%rax), %rbx
+ movq pt_regs_cx(%rax), %rcx
+ movq pt_regs_dx(%rax), %rdx
+ movq pt_regs_r8(%rax), %r8
+ movq pt_regs_r9(%rax), %r9
+ movq pt_regs_r10(%rax), %r10
+ movq pt_regs_r11(%rax), %r11
+ movq pt_regs_r12(%rax), %r12
+ movq pt_regs_r13(%rax), %r13
+ movq pt_regs_r14(%rax), %r14
+ movq pt_regs_r15(%rax), %r15
+ pushq pt_regs_flags(%rax)
+ popfq
+
+ /* Saved in save_processor_state. */
+ lgdt saved_context_gdt_desc(%rax)
+
+ xorl %eax, %eax
+
+ /* tell the hibernation core that we've just restored the memory */
+ movq %rax, in_suspend(%rip)
+
+ ret
+ENDPROC(restore_registers)