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authorLinus Torvalds <torvalds@linux-foundation.org>2017-08-17 14:21:18 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2017-08-17 14:21:18 -0700
commitd33a2a914319e9ec71f49bad2b8c8b9e05a58edf (patch)
tree4e4de33d81a96e99da477ed28e3eb5965be475d2 /arch
parent440105d3c958cf10b5900fac9d4632d47d57a0cc (diff)
parent8179962b84668d71586cd3efcb70e823f37a5702 (diff)
Merge tag 'pm-4.13-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm
Pull power management fixes from Rafael Wysocki: "These fix two issues related to exposing the current CPU frequency to user space on x86. Specifics: - Disable interrupts around reading IA32_APERF and IA32_MPERF in aperfmperf_snapshot_khz() (introduced recently) to avoid excessive delays between the reads that may result from interrupt handling (Doug Smythies). - Fix the computation of the CPU frequency to be reported through the pstate_sample tracepoint in intel_pstate (Doug Smythies)" * tag 'pm-4.13-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm: cpufreq: x86: Disable interrupts during MSRs reading cpufreq: intel_pstate: report correct CPU frequencies during trace
Diffstat (limited to 'arch')
-rw-r--r--arch/x86/kernel/cpu/aperfmperf.c3
1 files changed, 3 insertions, 0 deletions
diff --git a/arch/x86/kernel/cpu/aperfmperf.c b/arch/x86/kernel/cpu/aperfmperf.c
index 7cf7c70b6ef2..0ee83321a313 100644
--- a/arch/x86/kernel/cpu/aperfmperf.c
+++ b/arch/x86/kernel/cpu/aperfmperf.c
@@ -40,13 +40,16 @@ static void aperfmperf_snapshot_khz(void *dummy)
struct aperfmperf_sample *s = this_cpu_ptr(&samples);
ktime_t now = ktime_get();
s64 time_delta = ktime_ms_delta(now, s->time);
+ unsigned long flags;
/* Don't bother re-computing within the cache threshold time. */
if (time_delta < APERFMPERF_CACHE_THRESHOLD_MS)
return;
+ local_irq_save(flags);
rdmsrl(MSR_IA32_APERF, aperf);
rdmsrl(MSR_IA32_MPERF, mperf);
+ local_irq_restore(flags);
aperf_delta = aperf - s->aperf;
mperf_delta = mperf - s->mperf;