diff options
Diffstat (limited to 'arch/x86/kernel/cpu/mce/intel.c')
| -rw-r--r-- | arch/x86/kernel/cpu/mce/intel.c | 15 |
1 files changed, 8 insertions, 7 deletions
diff --git a/arch/x86/kernel/cpu/mce/intel.c b/arch/x86/kernel/cpu/mce/intel.c index e270d0770134..5627b1091b85 100644 --- a/arch/x86/kernel/cpu/mce/intel.c +++ b/arch/x86/kernel/cpu/mce/intel.c @@ -115,15 +115,16 @@ static bool lmce_supported(void) /* * BIOS should indicate support for LMCE by setting bit 20 in - * IA32_FEATURE_CONTROL without which touching MCG_EXT_CTL will - * generate a #GP fault. + * IA32_FEAT_CTL without which touching MCG_EXT_CTL will generate a #GP + * fault. The MSR must also be locked for LMCE_ENABLED to take effect. + * WARN if the MSR isn't locked as init_ia32_feat_ctl() unconditionally + * locks the MSR in the event that it wasn't already locked by BIOS. */ - rdmsrl(MSR_IA32_FEATURE_CONTROL, tmp); - if ((tmp & (FEATURE_CONTROL_LOCKED | FEATURE_CONTROL_LMCE)) == - (FEATURE_CONTROL_LOCKED | FEATURE_CONTROL_LMCE)) - return true; + rdmsrl(MSR_IA32_FEAT_CTL, tmp); + if (WARN_ON_ONCE(!(tmp & FEAT_CTL_LOCKED))) + return false; - return false; + return tmp & FEAT_CTL_LMCE_ENABLED; } bool mce_intel_cmci_poll(void) |