linux-kernel - [PATCH v2 7/8] drivers/perf: arm

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Message-Id: <20211201134909.390490-8-maz@kernel.org>
Date:   Wed,  1 Dec 2021 13:49:08 +0000
From:   Marc Zyngier <maz@...nel.org>
To:     linux-arm-kernel@...ts.infradead.org, devicetree@...r.kernel.org,
        linux-kernel@...r.kernel.org
Cc:     Mark Rutland <mark.rutland@....com>, Will Deacon <will@...nel.org>,
        Hector Martin <marcan@...can.st>,
        Sven Peter <sven@...npeter.dev>,
        Alyssa Rosenzweig <alyssa@...enzweig.io>,
        Rob Herring <robh+dt@...nel.org>,
        Thomas Gleixner <tglx@...utronix.de>,
        Dougall <dougallj@...il.com>, kernel-team@...roid.com
Subject: [PATCH v2 7/8] drivers/perf: arm_pmu: Handle 47 bit counters

The current ARM PMU framework can only deal with 32 or 64bit counters.
Teach it about a 47bit flavour.

Yes, this is odd.

Signed-off-by: Marc Zyngier <maz@...nel.org>
---
 drivers/perf/arm_pmu.c       | 2 ++
 include/linux/perf/arm_pmu.h | 2 ++
 2 files changed, 4 insertions(+)

diff --git a/drivers/perf/arm_pmu.c b/drivers/perf/arm_pmu.c
index 295cc7952d0e..0a9ed1a061ac 100644
--- a/drivers/perf/arm_pmu.c
+++ b/drivers/perf/arm_pmu.c
@@ -109,6 +109,8 @@ static inline u64 arm_pmu_event_max_period(struct perf_event *event)
 {
 	if (event->hw.flags & ARMPMU_EVT_64BIT)
 		return GENMASK_ULL(63, 0);
+	else if (event->hw.flags & ARMPMU_EVT_47BIT)
+		return GENMASK_ULL(46, 0);
 	else
 		return GENMASK_ULL(31, 0);
 }
diff --git a/include/linux/perf/arm_pmu.h b/include/linux/perf/arm_pmu.h
index 2512e2f9cd4e..0407a38b470a 100644
--- a/include/linux/perf/arm_pmu.h
+++ b/include/linux/perf/arm_pmu.h
@@ -26,6 +26,8 @@
  */
 /* Event uses a 64bit counter */
 #define ARMPMU_EVT_64BIT		1
+/* Event uses a 47bit counter */
+#define ARMPMU_EVT_47BIT		2
 
 #define HW_OP_UNSUPPORTED		0xFFFF
 #define C(_x)				PERF_COUNT_HW_CACHE_##_x
-- 
2.30.2