linux-kernel - [PATCH 4.18 130/135] arm64: perf: Reject stand-alone CHAIN events for PMUv3

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Message-Id: <20181016170524.260269756@linuxfoundation.org>
Date:   Tue, 16 Oct 2018 19:06:00 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Suzuki K Poulose <suzuki.poulose@....com>,
        Will Deacon <will.deacon@....com>
Subject: [PATCH 4.18 130/135] arm64: perf: Reject stand-alone CHAIN events for PMUv3

4.18-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Will Deacon <will.deacon@....com>

commit ca2b497253ad01c80061a1f3ee9eb91b5d54a849 upstream.

It doesn't make sense for a perf event to be configured as a CHAIN event
in isolation, so extend the arm_pmu structure with a ->filter_match()
function to allow the backend PMU implementation to reject CHAIN events
early.

Cc: <stable@...r.kernel.org>
Reviewed-by: Suzuki K Poulose <suzuki.poulose@....com>
Signed-off-by: Will Deacon <will.deacon@....com>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

---
 arch/arm64/kernel/perf_event.c |    7 +++++++
 drivers/perf/arm_pmu.c         |    8 +++++++-
 include/linux/perf/arm_pmu.h   |    1 +
 3 files changed, 15 insertions(+), 1 deletion(-)

--- a/arch/arm64/kernel/perf_event.c
+++ b/arch/arm64/kernel/perf_event.c
@@ -823,6 +823,12 @@ static int armv8pmu_set_event_filter(str
 	return 0;
 }
 
+static int armv8pmu_filter_match(struct perf_event *event)
+{
+	unsigned long evtype = event->hw.config_base & ARMV8_PMU_EVTYPE_EVENT;
+	return evtype != ARMV8_PMUV3_PERFCTR_CHAIN;
+}
+
 static void armv8pmu_reset(void *info)
 {
 	struct arm_pmu *cpu_pmu = (struct arm_pmu *)info;
@@ -968,6 +974,7 @@ static int armv8_pmu_init(struct arm_pmu
 	cpu_pmu->reset			= armv8pmu_reset,
 	cpu_pmu->max_period		= (1LLU << 32) - 1,
 	cpu_pmu->set_event_filter	= armv8pmu_set_event_filter;
+	cpu_pmu->filter_match		= armv8pmu_filter_match;
 
 	return 0;
 }
--- a/drivers/perf/arm_pmu.c
+++ b/drivers/perf/arm_pmu.c
@@ -474,7 +474,13 @@ static int armpmu_filter_match(struct pe
 {
 	struct arm_pmu *armpmu = to_arm_pmu(event->pmu);
 	unsigned int cpu = smp_processor_id();
-	return cpumask_test_cpu(cpu, &armpmu->supported_cpus);
+	int ret;
+
+	ret = cpumask_test_cpu(cpu, &armpmu->supported_cpus);
+	if (ret && armpmu->filter_match)
+		return armpmu->filter_match(event);
+
+	return ret;
 }
 
 static ssize_t armpmu_cpumask_show(struct device *dev,
--- a/include/linux/perf/arm_pmu.h
+++ b/include/linux/perf/arm_pmu.h
@@ -93,6 +93,7 @@ struct arm_pmu {
 	void		(*stop)(struct arm_pmu *);
 	void		(*reset)(void *);
 	int		(*map_event)(struct perf_event *event);
+	int		(*filter_match)(struct perf_event *event);
 	int		num_events;
 	u64		max_period;
 	bool		secure_access; /* 32-bit ARM only */