[PATCH] perf: arm_pmuv3: Fix chained event check for cycle counter

From: Rob Herring (Arm)
Date: Wed Jul 10 2024 - 14:24:19 EST


Since commit b7e89b0f5bd7 ("perf: arm_pmu: Remove event index to
counter remapping"), armv8pmu_event_is_chained() is incorrectly
returning that the cycle counter is chained, but the cycle counter has
always been 64-bit. The result is trying to configure counter #30 which
typically doesn't exist.

As ARMV8_PMU_MAX_GENERAL_COUNTERS is the number of counters (31), the
comparison to the counter index needs to be '<' rather than '<='.

Fixes: b7e89b0f5bd7 ("perf: arm_pmu: Remove event index to counter remapping")
Signed-off-by: Rob Herring (Arm) <robh@xxxxxxxxxx>
---
drivers/perf/arm_pmuv3.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/perf/arm_pmuv3.c b/drivers/perf/arm_pmuv3.c
index 3b3a3334cc3f..0e22c68fb804 100644
--- a/drivers/perf/arm_pmuv3.c
+++ b/drivers/perf/arm_pmuv3.c
@@ -482,7 +482,7 @@ static bool armv8pmu_event_is_chained(struct perf_event *event)
return !armv8pmu_event_has_user_read(event) &&
armv8pmu_event_is_64bit(event) &&
!armv8pmu_has_long_event(cpu_pmu) &&
- (idx <= ARMV8_PMU_MAX_GENERAL_COUNTERS);
+ (idx < ARMV8_PMU_MAX_GENERAL_COUNTERS);
}

/*
--
2.43.0