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Diffstat (limited to 'arch/x86/kernel/acpi/sleep.c')
-rw-r--r--arch/x86/kernel/acpi/sleep.c18
1 files changed, 16 insertions, 2 deletions
diff --git a/arch/x86/kernel/acpi/sleep.c b/arch/x86/kernel/acpi/sleep.c
index b44577bc9744..ec94e11807dc 100644
--- a/arch/x86/kernel/acpi/sleep.c
+++ b/arch/x86/kernel/acpi/sleep.c
@@ -48,9 +48,20 @@ int 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 IntelĀ® 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 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;