diff options
| author | Thomas Gleixner <tglx@linutronix.de> | 2016-11-19 13:47:33 +0000 |
|---|---|---|
| committer | Thomas Gleixner <tglx@linutronix.de> | 2016-11-29 19:23:15 +0100 |
| commit | 7b3d2f6e08ed5eb6bcf6912938f7a542405f8e8e (patch) | |
| tree | 0e6940350eeba63f102e93b8fb34b6f7e47df97c /arch/x86/kernel/tsc.c | |
| parent | 984fecebda3b9c8e3d75f8492593da71c58972b3 (diff) | |
x86/tsc: Use X86_FEATURE_TSC_ADJUST in detect_art()
The art detection uses rdmsrl_safe() to detect the availablity of the
TSC_ADJUST MSR.
That's pointless because we have a feature bit for this. Use it.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Ingo Molnar <mingo@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Link: http://lkml.kernel.org/r/20161119134017.483561692@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Diffstat (limited to 'arch/x86/kernel/tsc.c')
| -rw-r--r-- | arch/x86/kernel/tsc.c | 14 |
1 files changed, 8 insertions, 6 deletions
diff --git a/arch/x86/kernel/tsc.c b/arch/x86/kernel/tsc.c index 0ff1ec61d1e4..2b27c5ae9d1f 100644 --- a/arch/x86/kernel/tsc.c +++ b/arch/x86/kernel/tsc.c @@ -1057,18 +1057,20 @@ static void detect_art(void) if (boot_cpu_data.cpuid_level < ART_CPUID_LEAF) return; - cpuid(ART_CPUID_LEAF, &art_to_tsc_denominator, - &art_to_tsc_numerator, unused, unused+1); - - /* Don't enable ART in a VM, non-stop TSC required */ + /* Don't enable ART in a VM, non-stop TSC and TSC_ADJUST required */ if (boot_cpu_has(X86_FEATURE_HYPERVISOR) || !boot_cpu_has(X86_FEATURE_NONSTOP_TSC) || - art_to_tsc_denominator < ART_MIN_DENOMINATOR) + !boot_cpu_has(X86_FEATURE_TSC_ADJUST)) return; - if (rdmsrl_safe(MSR_IA32_TSC_ADJUST, &art_to_tsc_offset)) + cpuid(ART_CPUID_LEAF, &art_to_tsc_denominator, + &art_to_tsc_numerator, unused, unused+1); + + if (art_to_tsc_denominator < ART_MIN_DENOMINATOR) return; + rdmsrl(MSR_IA32_TSC_ADJUST, art_to_tsc_offset); + /* Make this sticky over multiple CPU init calls */ setup_force_cpu_cap(X86_FEATURE_ART); } |