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

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;