/* * Suspend support specific for i386/x86-64. * * Distribute under GPLv2 * * Copyright (c) 2007 Rafael J. Wysocki * Copyright (c) 2002 Pavel Machek * Copyright (c) 2001 Patrick Mochel */ #include #include #include #include #include #include #include #include #include #include #include #include /* pcntxt_mask */ #include #ifdef CONFIG_X86_32 static struct saved_context saved_context; unsigned long saved_context_ebx; unsigned long saved_context_esp, saved_context_ebp; unsigned long saved_context_esi, saved_context_edi; unsigned long saved_context_eflags; #else /* CONFIG_X86_64 */ struct saved_context saved_context; #endif /** * __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 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(); #ifdef CONFIG_X86_32 ctxt->cr4 = read_cr4_safe(); #else /* CONFIG_X86_64 */ ctxt->cr4 = read_cr4(); 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(init_tss, cpu); 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 get_cpu_gdt_table(cpu)[GDT_ENTRY_TSS].type = 9; 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 __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(); } /* Needed by apm.c */ void 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);