arm64: perf: Reject stand-alone CHAIN events for PMUv3

wildea01 · wildea01 · commit ca2b497253ad · 2018-10-12T15:25:17.000+01:00
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 -&gt;filter_match()
function to allow the backend PMU implementation to reject CHAIN events
early.

Cc: &lt;stable@vger.kernel.org&gt;
Reviewed-by: Suzuki K Poulose &lt;suzuki.poulose@arm.com&gt;
Signed-off-by: Will Deacon &lt;will.deacon@arm.com&gt;
diff --git a/arch/arm64/kernel/perf_event.c b/arch/arm64/kernel/perf_event.c
@@ -966,6 +966,12 @@ static int armv8pmu_set_event_filter(struct hw_perf_event *event,
 	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;
@@ -1114,6 +1120,7 @@ static int armv8_pmu_init(struct arm_pmu *cpu_pmu)
 	cpu_pmu->stop			= armv8pmu_stop,
 	cpu_pmu->reset			= armv8pmu_reset,
 	cpu_pmu->set_event_filter	= armv8pmu_set_event_filter;
+	cpu_pmu->filter_match		= armv8pmu_filter_match;
 
 	return 0;
 }
diff --git a/drivers/perf/arm_pmu.c b/drivers/perf/arm_pmu.c
@@ -485,7 +485,13 @@ static int armpmu_filter_match(struct perf_event *event)
 {
 	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,
diff --git a/include/linux/perf/arm_pmu.h b/include/linux/perf/arm_pmu.h
@@ -99,6 +99,7 @@ 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;
 	bool		secure_access; /* 32-bit ARM only */
 #define ARMV8_PMUV3_MAX_COMMON_EVENTS 0x40

Original file line number	Diff line number	Diff line change
`@@ -966,6 +966,12 @@ static int armv8pmu_set_event_filter(struct hw_perf_event *event,`
`966`	`966`	`return 0;`
`967`	`967`	`}`
`968`	`968`
	`969`	`+static int armv8pmu_filter_match(struct perf_event *event)`
	`970`	`+{`
	`971`	`+ unsigned long evtype = event->hw.config_base & ARMV8_PMU_EVTYPE_EVENT;`
	`972`	`+ return evtype != ARMV8_PMUV3_PERFCTR_CHAIN;`
	`973`	`+}`
	`974`	`+`
`969`	`975`	`static void armv8pmu_reset(void *info)`
`970`	`976`	`{`
`971`	`977`	`struct arm_pmu cpu_pmu = (struct arm_pmu )info;`
`@@ -1114,6 +1120,7 @@ static int armv8_pmu_init(struct arm_pmu *cpu_pmu)`
`1114`	`1120`	`cpu_pmu->stop = armv8pmu_stop,`
`1115`	`1121`	`cpu_pmu->reset = armv8pmu_reset,`
`1116`	`1122`	`cpu_pmu->set_event_filter = armv8pmu_set_event_filter;`
	`1123`	`+ cpu_pmu->filter_match = armv8pmu_filter_match;`
`1117`	`1124`
`1118`	`1125`	`return 0;`
`1119`	`1126`	`}`
Original file line number	Diff line number	Diff line change
`@@ -485,7 +485,13 @@ static int armpmu_filter_match(struct perf_event *event)`
`485`	`485`	`{`
`486`	`486`	`struct arm_pmu *armpmu = to_arm_pmu(event->pmu);`
`487`	`487`	`unsigned int cpu = smp_processor_id();`
`488`		`- return cpumask_test_cpu(cpu, &armpmu->supported_cpus);`
	`488`	`+ int ret;`
	`489`	`+`
	`490`	`+ ret = cpumask_test_cpu(cpu, &armpmu->supported_cpus);`
	`491`	`+ if (ret && armpmu->filter_match)`
	`492`	`+ return armpmu->filter_match(event);`
	`493`	`+`
	`494`	`+ return ret;`
`489`	`495`	`}`
`490`	`496`
`491`	`497`	`static ssize_t armpmu_cpumask_show(struct device *dev,`