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Subject[PATCH V2] arm64: perf: Retain PMCR.X of PMCR_EL0 during reset
Date
Preserve the bit PMCR.X of PMCR_EL0 during PMU reset to export
PMU events. as it could be set before PMU initialization.

Signed-off-by: Srinivasarao Pathipati <quic_c_spathi@quicinc.com>
---
Changes since V1:
- Preserving only PMCR_X bit as per Robin Murphy's comment
---
arch/arm64/kernel/perf_event.c | 3 +++
1 file changed, 3 insertions(+)

diff --git a/arch/arm64/kernel/perf_event.c b/arch/arm64/kernel/perf_event.c
index cb69ff1..532a417 100644
--- a/arch/arm64/kernel/perf_event.c
+++ b/arch/arm64/kernel/perf_event.c
@@ -1047,6 +1047,9 @@ static void armv8pmu_reset(void *info)
if (armv8pmu_has_long_event(cpu_pmu))
pmcr |= ARMV8_PMU_PMCR_LP;

+ /* Preserve PMCR_X to export PMU events */
+ pmcr |= (armv8pmu_pmcr_read() & ARMV8_PMU_PMCR_X);
+
armv8pmu_pmcr_write(pmcr);
}

--
2.7.4
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