[PATCH v12 1/8] arm64: arm_pmu: remove unnecessary isb instruction
andrew.murray at arm.com
Thu Mar 28 03:37:24 PDT 2019
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 at arm.com>
Reviewed-by: Suzuki K Poulose <suzuki.poulose at arm.com>
Acked-by: Mark Rutland <mark.rutland at arm.com>
arch/arm64/kernel/perf_event.c | 1 -
1 file changed, 1 deletion(-)
diff --git a/arch/arm64/kernel/perf_event.c b/arch/arm64/kernel/perf_event.c
index 4addb38bc250..cccf4fc86d67 100644
@@ -533,7 +533,6 @@ static inline void armv8pmu_enable_event_counter(struct perf_event *event)
armv8pmu_enable_counter(idx - 1);
static inline int armv8pmu_disable_counter(int idx)
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