diff options
| -rw-r--r-- | arch/x86/kernel/suspend_64.c | 20 | ||||
| -rw-r--r-- | include/asm-x86/suspend_64.h | 9 |
2 files changed, 28 insertions, 1 deletions
diff --git a/arch/x86/kernel/suspend_64.c b/arch/x86/kernel/suspend_64.c index 2e5efaa..569f1b5 100644 --- a/arch/x86/kernel/suspend_64.c +++ b/arch/x86/kernel/suspend_64.c @@ -19,6 +19,21 @@ extern const void __nosave_begin, __nosave_end; 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. + */ void __save_processor_state(struct saved_context *ctxt) { kernel_fpu_begin(); @@ -69,6 +84,11 @@ static void do_fpu_end(void) kernel_fpu_end(); } +/** + * __restore_processor_state - restore the contents of CPU registers saved + * by __save_processor_state() + * @ctxt - structure to load the registers contents from + */ void __restore_processor_state(struct saved_context *ctxt) { /* diff --git a/include/asm-x86/suspend_64.h b/include/asm-x86/suspend_64.h index c505a76..4404668 100644 --- a/include/asm-x86/suspend_64.h +++ b/include/asm-x86/suspend_64.h @@ -15,7 +15,14 @@ arch_prepare_suspend(void) return 0; } -/* Image of the saved processor state. If you touch this, fix acpi/wakeup.S. */ +/* + * Image of the saved processor state, used by the low level ACPI suspend to + * RAM code and by the low level hibernation code. + * + * If you modify it, fix arch/x86/kernel/acpi/wakeup_64.S and make sure that + * __save/__restore_processor_state(), defined in arch/x86/kernel/suspend_64.c, + * still work as required. + */ struct saved_context { struct pt_regs regs; u16 ds, es, fs, gs, ss; |
