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arm64: arm_pmu: Remove unnecessary isb instruction 

The armv8pmu_enable_event_counter function issues an isb instruction
after enabling a pair of counters - this doesn't provide any value
and is inconsistent with the armv8pmu_disable_event_counter.

In any case armv8pmu_enable_event_counter is always called with the
PMU stopped. Starting the PMU with armv8pmu_start results in an isb
instruction being issued prior to writing to PMCR_EL0.

Let's remove the unnecessary isb instruction.

Signed-off-by: Andrew Murray <andrew.murray@arm.com>
Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
hifive-unleashed-5.2
Andrew Murray 2019-04-09 20:22:10 +01:00 committed by Marc Zyngier
parent a243c16d18
commit 21bb0ebf5d
1 changed files with 0 additions and 1 deletions
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arch/arm64/kernel/perf_event.c
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@ -533,7 +533,6 @@ static inline void armv8pmu_enable_event_counter(struct perf_event *event)
armv8pmu_enable_counter(idx);
if (armv8pmu_event_is_chained(event))
armv8pmu_enable_counter(idx - 1);
isb();
}
static inline int armv8pmu_disable_counter(int idx)