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Commit 21bb0ebf authored by Andrew Murray's avatar Andrew Murray Committed by Marc Zyngier
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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: default avatarAndrew Murray <andrew.murray@arm.com>
Reviewed-by: default avatarSuzuki K Poulose <suzuki.poulose@arm.com>
Acked-by: default avatarMark Rutland <mark.rutland@arm.com>
Signed-off-by: default avatarMarc Zyngier <marc.zyngier@arm.com>
parent a243c16d

arch/arm64/kernel/perf_event.c

+0 −1
Original line number Diff line number Diff line
@@ -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)