linux-kernel - [PATCH 3/7] perf: arm_pmuv3: Don't disable counter in armv8pmu_enable

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Message-Id: <20250107-arm-pmu-cleanups-v1-v1-3-313951346a25@kernel.org>
Date: Tue, 07 Jan 2025 11:57:21 -0600
From: "Rob Herring (Arm)" <robh@...nel.org>
To: Will Deacon <will@...nel.org>, Mark Rutland <mark.rutland@....com>
Cc: Marc Zyngier <maz@...nel.org>, linux-arm-kernel@...ts.infradead.org, 
 linux-kernel@...r.kernel.org
Subject: [PATCH 3/7] perf: arm_pmuv3: Don't disable counter in
 armv8pmu_enable_event()

From: Mark Rutland <mark.rutland@....com>

Currently armv8pmu_enable_event() starts by disabling the event counter
it has been asked to enable. This should not be necessary as the counter
(and the PMU as a whole) should not be active when
armv8pmu_enable_event() is called.

Remove the redundant call to armv8pmu_disable_event_counter(). At the
same time, remove the comment immeditately above as everything it says
is obvious from the function names below.

Signed-off-by: Mark Rutland <mark.rutland@....com>
Signed-off-by: Rob Herring (Arm) <robh@...nel.org>
---
 drivers/perf/arm_pmuv3.c | 5 -----
 1 file changed, 5 deletions(-)

diff --git a/drivers/perf/arm_pmuv3.c b/drivers/perf/arm_pmuv3.c
index dfef8d4669f58eb7f989a9582164b00a823ac60b..7a1056e1e686146c2c7b20f62d19d384f1ae422b 100644
--- a/drivers/perf/arm_pmuv3.c
+++ b/drivers/perf/arm_pmuv3.c
@@ -795,11 +795,6 @@ static void armv8pmu_enable_user_access(struct arm_pmu *cpu_pmu)
 
 static void armv8pmu_enable_event(struct perf_event *event)
 {
-	/*
-	 * Enable counter and interrupt, and set the counter to count
-	 * the event that we're interested in.
-	 */
-	armv8pmu_disable_event_counter(event);
 	armv8pmu_write_event_type(event);
 	armv8pmu_enable_event_irq(event);
 	armv8pmu_enable_event_counter(event);

-- 
2.45.2