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perf/x86/intel: Properly save/restore the PMU state in the NMI handler 

The PMU is disabled in intel_pmu_handle_irq(), but cpuc->enabled is not updated
accordingly.

This is fine in current usage because no-one checks it - but fix it
for future code: for example, the drain_pebs() will be modified to
fix an auto-reload bug.

Properly save/restore the old PMU state.

Signed-off-by: Kan Liang <kan.liang@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Cc: acme@kernel.org
Cc: kernel test robot <fengguang.wu@intel.com>
Link: http://lkml.kernel.org/r/6f44ee84-56f8-79f1-559b-08e371eaeb78@linux.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Kan Liang 2018-02-20 02:11:50 -08:00 committed by Ingo Molnar
parent f605cfca8c
commit 82d71ed027
1 changed files with 9 additions and 1 deletions
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10
arch/x86/events/intel/core.c
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@ -2201,9 +2201,15 @@ static int intel_pmu_handle_irq(struct pt_regs *regs)
int bit, loops;
u64 status;
int handled;
int pmu_enabled;
cpuc = this_cpu_ptr(&cpu_hw_events);
/*
* Save the PMU state.
* It needs to be restored when leaving the handler.
*/
pmu_enabled = cpuc->enabled;
/*
* No known reason to not always do late ACK,
* but just in case do it opt-in.
@ -2211,6 +2217,7 @@ static int intel_pmu_handle_irq(struct pt_regs *regs)
if (!x86_pmu.late_ack)
apic_write(APIC_LVTPC, APIC_DM_NMI);
intel_bts_disable_local();
cpuc->enabled = 0;
__intel_pmu_disable_all();
handled = intel_pmu_drain_bts_buffer();
handled += intel_bts_interrupt();
@ -2320,7 +2327,8 @@ again:
done:
/* Only restore PMU state when it's active. See x86_pmu_disable(). */
if (cpuc->enabled)
cpuc->enabled = pmu_enabled;
if (pmu_enabled)
__intel_pmu_enable_all(0, true);
intel_bts_enable_local();