From: Julien Thierry <julien.thierry@arm.com>
To: linux-arm-kernel@lists.infradead.org
Cc: Mark Rutland <mark.rutland@arm.com>,
Julien Thierry <julien.thierry@arm.com>,
Peter Zijlstra <peterz@infradead.org>,
Catalin Marinas <catalin.marinas@arm.com>,
Jiri Olsa <jolsa@redhat.com>, Will Deacon <will.deacon@arm.com>,
Arnaldo Carvalho de Melo <acme@kernel.org>,
Alexander Shishkin <alexander.shishkin@linux.intel.com>,
Ingo Molnar <mingo@redhat.com>,
huawei.libin@huawei.com, guohanjun@huawei.com,
Namhyung Kim <namhyung@kernel.org>,
liwei391@huawei.com
Subject: [PATCH] arm64: perf: Do not write event type for cycle counter
Date: Thu, 28 Mar 2019 09:49:05 +0000 [thread overview]
Message-ID: <1553766545-27692-1-git-send-email-julien.thierry@arm.com> (raw)
Perf events using the dedicated cycle counter do not need to program the
event type, the counter only ever counts that kind of events.
Even worse, trying to program an event type without excluding the
cycle counter index might end up in the modification of the type of
event counted by another perf event.
Reported-by: Wei Li <liwei391@huawei.com>
Signed-off-by: Julien Thierry <julien.thierry@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
---
arch/arm64/kernel/perf_event.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/arm64/kernel/perf_event.c b/arch/arm64/kernel/perf_event.c
index 4addb38..3f898bc 100644
--- a/arch/arm64/kernel/perf_event.c
+++ b/arch/arm64/kernel/perf_event.c
@@ -514,7 +514,7 @@ static inline void armv8pmu_write_event_type(struct perf_event *event)
armv8pmu_write_evtype(idx - 1, hwc->config_base);
armv8pmu_write_evtype(idx, chain_evt);
- } else {
+ } else if (idx != ARMV8_IDX_CYCLE_COUNTER) {
armv8pmu_write_evtype(idx, hwc->config_base);
}
}
--
1.9.1
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next reply other threads:[~2019-03-28 9:49 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-03-28 9:49 Julien Thierry [this message]
2019-04-01 8:02 ` [PATCH] arm64: perf: Do not write event type for cycle counter Mark Rutland
2019-04-02 15:42 ` Julien Thierry
2019-04-03 3:10 ` Mark Rutland
2019-04-03 7:26 ` Julien Thierry
2019-04-03 13:54 ` Will Deacon
2019-04-03 14:09 ` Julien Thierry
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