[PATCH 4.14 075/109] arm64: perf: Reject stand-alone CHAIN events for PMUv3

Greg Kroah-Hartman
2018-10-16T17:20:37Z

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

---
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
@@ -824,6 +824,12 @@ 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;
@@ -970,6 +976,7 @@ 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
@@ -483,7 +483,13 @@ 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
@@ -110,6 +110,7 @@ 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 */