From d6a77ead21b69c395ca6d09a066ededfac601bcc Mon Sep 17 00:00:00 2001 From: Konrad Rzeszutek Wilk Date: Tue, 14 May 2013 17:09:16 +0000 Subject: x86 / ACPI / sleep: Provide registration for acpi_suspend_lowlevel. Which by default will be x86_acpi_suspend_lowlevel. This registration allows us to register another callback if there is a need to use another platform specific callback. Signed-off-by: Liang Tang Signed-off-by: Konrad Rzeszutek Wilk Tested-by: Ben Guthro Acked-by: "H. Peter Anvin" Signed-off-by: Rafael J. Wysocki --- arch/x86/kernel/acpi/sleep.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'arch/x86/kernel/acpi/sleep.c') diff --git a/arch/x86/kernel/acpi/sleep.c b/arch/x86/kernel/acpi/sleep.c index b44577bc9744..2a34aaf3c8f1 100644 --- a/arch/x86/kernel/acpi/sleep.c +++ b/arch/x86/kernel/acpi/sleep.c @@ -26,12 +26,12 @@ static char temp_stack[4096]; #endif /** - * acpi_suspend_lowlevel - save kernel state + * x86_acpi_suspend_lowlevel - save kernel state * * Create an identity mapped page table and copy the wakeup routine to * low memory. */ -int acpi_suspend_lowlevel(void) +int x86_acpi_suspend_lowlevel(void) { struct wakeup_header *header = (struct wakeup_header *) __va(real_mode_header->wakeup_header); -- cgit v1.2.3 From 5ff560fd48d5b3d82fa0c3aff625c9da1a301911 Mon Sep 17 00:00:00 2001 From: "H. Peter Anvin" Date: Fri, 12 Jul 2013 16:48:12 -0700 Subject: x86, suspend: Handle CPUs which fail to #GP on RDMSR MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit There are CPUs which have errata causing RDMSR of a nonexistent MSR to not fault. We would then try to WRMSR to restore the value of that MSR, causing a crash. Specifically, some Pentium M variants would have this problem trying to save and restore the non-existent EFER, causing a crash on resume. Work around this by making sure we can write back the result at suspend time. Huge thanks to Christian Sünkenberg for finding the offending erratum that finally deciphered the mystery. Reported-and-tested-by: Johan Heinrich Debugged-by: Christian Sünkenberg Acked-by: Rafael J. Wysocki Link: http://lkml.kernel.org/r/51DDC972.3010005@student.kit.edu Cc: # v3.7+ --- arch/x86/kernel/acpi/sleep.c | 18 ++++++++++++++++-- 1 file changed, 16 insertions(+), 2 deletions(-) (limited to 'arch/x86/kernel/acpi/sleep.c') diff --git a/arch/x86/kernel/acpi/sleep.c b/arch/x86/kernel/acpi/sleep.c index 2a34aaf3c8f1..33120100ff5e 100644 --- a/arch/x86/kernel/acpi/sleep.c +++ b/arch/x86/kernel/acpi/sleep.c @@ -48,9 +48,20 @@ int x86_acpi_suspend_lowlevel(void) #ifndef CONFIG_64BIT native_store_gdt((struct desc_ptr *)&header->pmode_gdt); + /* + * We have to check that we can write back the value, and not + * just read it. At least on 90 nm Pentium M (Family 6, Model + * 13), reading an invalid MSR is not guaranteed to trap, see + * Erratum X4 in "Intel Pentium M Processor on 90 nm Process + * with 2-MB L2 Cache and Intel® Processor A100 and A110 on 90 + * nm process with 512-KB L2 Cache Specification Update". + */ if (!rdmsr_safe(MSR_EFER, &header->pmode_efer_low, - &header->pmode_efer_high)) + &header->pmode_efer_high) && + !wrmsr_safe(MSR_EFER, + header->pmode_efer_low, + header->pmode_efer_high)) header->pmode_behavior |= (1 << WAKEUP_BEHAVIOR_RESTORE_EFER); #endif /* !CONFIG_64BIT */ @@ -61,7 +72,10 @@ int x86_acpi_suspend_lowlevel(void) } if (!rdmsr_safe(MSR_IA32_MISC_ENABLE, &header->pmode_misc_en_low, - &header->pmode_misc_en_high)) + &header->pmode_misc_en_high) && + !wrmsr_safe(MSR_IA32_MISC_ENABLE, + header->pmode_misc_en_low, + header->pmode_misc_en_high)) header->pmode_behavior |= (1 << WAKEUP_BEHAVIOR_RESTORE_MISC_ENABLE); header->realmode_flags = acpi_realmode_flags; -- cgit v1.2.3