diff options
Diffstat (limited to 'kernel/arch/x86/power/cpu.c')
| -rw-r--r-- | kernel/arch/x86/power/cpu.c | 326 |
1 files changed, 326 insertions, 0 deletions
diff --git a/kernel/arch/x86/power/cpu.c b/kernel/arch/x86/power/cpu.c new file mode 100644 index 000000000..757678fb2 --- /dev/null +++ b/kernel/arch/x86/power/cpu.c @@ -0,0 +1,326 @@ +/* + * 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 <asm/pgtable.h> +#include <asm/proto.h> +#include <asm/mtrr.h> +#include <asm/page.h> +#include <asm/mce.h> +#include <asm/xcr.h> +#include <asm/suspend.h> +#include <asm/debugreg.h> +#include <asm/fpu-internal.h> /* pcntxt_mask */ +#include <asm/cpu.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; + +/** + * __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 + */ +#ifdef CONFIG_X86_32 + store_idt(&ctxt->idt); +#else +/* CONFIG_X86_64 */ + store_idt((struct desc_ptr *)&ctxt->idt_limit); +#endif + /* + * 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_table(smp_processor_id()); + + store_tr(ctxt->tr); + + /* XMM0..XMM15 should be handled by kernel_fpu_begin(). */ + /* + * segment registers + */ +#ifdef CONFIG_X86_32 + savesegment(es, ctxt->es); + savesegment(fs, ctxt->fs); + savesegment(gs, ctxt->gs); + savesegment(ss, ctxt->ss); +#else +/* CONFIG_X86_64 */ + asm volatile ("movw %%ds, %0" : "=m" (ctxt->ds)); + asm volatile ("movw %%es, %0" : "=m" (ctxt->es)); + asm volatile ("movw %%fs, %0" : "=m" (ctxt->fs)); + asm volatile ("movw %%gs, %0" : "=m" (ctxt->gs)); + asm volatile ("movw %%ss, %0" : "=m" (ctxt->ss)); + + rdmsrl(MSR_FS_BASE, ctxt->fs_base); + rdmsrl(MSR_GS_BASE, ctxt->gs_base); + rdmsrl(MSR_KERNEL_GS_BASE, ctxt->gs_kernel_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_safe(); +#ifdef CONFIG_X86_64 + ctxt->cr8 = read_cr8(); +#endif + ctxt->misc_enable_saved = !rdmsrl_safe(MSR_IA32_MISC_ENABLE, + &ctxt->misc_enable); +} + +/* 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(); + struct tss_struct *t = &per_cpu(cpu_tss, cpu); +#ifdef CONFIG_X86_64 + struct desc_struct *desc = get_cpu_gdt_table(cpu); + tss_desc tss; +#endif + set_tss_desc(cpu, t); /* + * This just modifies memory; should not be + * necessary. But... This is necessary, because + * 386 hardware has concept of busy TSS or some + * similar stupidity. + */ + +#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 */ +#endif + load_TR_desc(); /* This does ltr */ + load_LDT(¤t->active_mm->context); /* This does lldt */ +} + +/** + * __restore_processor_state - restore the contents of CPU registers saved + * by __save_processor_state() + * @ctxt - structure to load the registers contents from + */ +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); + + /* + * now restore the descriptor tables to their proper values + * ltr is done i fix_processor_context(). + */ +#ifdef CONFIG_X86_32 + load_idt(&ctxt->idt); +#else +/* CONFIG_X86_64 */ + load_idt((const struct desc_ptr *)&ctxt->idt_limit); +#endif + + /* + * segment registers + */ +#ifdef CONFIG_X86_32 + loadsegment(es, ctxt->es); + loadsegment(fs, ctxt->fs); + loadsegment(gs, ctxt->gs); + loadsegment(ss, ctxt->ss); + + /* + * sysenter MSRs + */ + if (boot_cpu_has(X86_FEATURE_SEP)) + enable_sep_cpu(); +#else +/* CONFIG_X86_64 */ + asm volatile ("movw %0, %%ds" :: "r" (ctxt->ds)); + asm volatile ("movw %0, %%es" :: "r" (ctxt->es)); + asm volatile ("movw %0, %%fs" :: "r" (ctxt->fs)); + load_gs_index(ctxt->gs); + asm volatile ("movw %0, %%ss" :: "r" (ctxt->ss)); + + wrmsrl(MSR_FS_BASE, ctxt->fs_base); + wrmsrl(MSR_GS_BASE, ctxt->gs_base); + wrmsrl(MSR_KERNEL_GS_BASE, ctxt->gs_kernel_base); +#endif + + /* + * restore XCR0 for xsave capable cpu's. + */ + if (cpu_has_xsave) + xsetbv(XCR_XFEATURE_ENABLED_MASK, pcntxt_mask); + + fix_processor_context(); + + do_fpu_end(); + x86_platform.restore_sched_clock_state(); + mtrr_bp_restore(); + perf_restore_debug_store(); +} + +/* 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 + +/* + * 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); |