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

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@vger.kernel.org>
Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/arch/arm64/kernel/perf_event.c b/arch/arm64/kernel/perf_event.c
index dd5b4fab114f8f2be390751aebe3e33916a68ed4..b7c8a718544ca74aaa58e083db58d161eac86da3 100644 (file)
--- a/arch/arm64/kernel/perf_event.c
+++ b/arch/arm64/kernel/perf_event.c
@@ -823,6 +823,12 @@ 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;
@@ -968,6 +974,7 @@ static int armv8_pmu_init(struct arm_pmu *cpu_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;
 }

diff --git a/drivers/perf/arm_pmu.c b/drivers/perf/arm_pmu.c
index a6347d4876356c09338c99d4bd9a2fb414e9e590..1321104b9b9f3af0c72dfb96d8cbf4dd0108e40e 100644 (file)
--- a/drivers/perf/arm_pmu.c
+++ b/drivers/perf/arm_pmu.c
@@ -474,7 +474,13 @@ 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
index ad5444491975c0b990b5092d023b5f158641fd75..a2f6e178a2d755f49e8db51ea7ad7675675cece9 100644 (file)
--- 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 */