[PATCH 3/3] arm-cci: Reject groups spanning multiple HW PMUs

Suzuki K. Poulose
2015-03-09T12:47:23Z

From: "Suzuki K. Poulose" <suzuki.poulose@arm.com>

Invalidate an event if the group has a hardware event from
a different PMU as we cannot schedule all of them in the same
context. The perf core code won't check the group consistency
until after pmu_event_init().

Signed-off-by: Suzuki K. Poulose <suzuki.poulose@arm.com>
---
drivers/bus/arm-cci.c | 19 ++++++++++++++-----
1 file changed, 14 insertions(+), 5 deletions(-)

diff --git a/drivers/bus/arm-cci.c b/drivers/bus/arm-cci.c
index 84fd660..68ef6f2 100644
--- a/drivers/bus/arm-cci.c
+++ b/drivers/bus/arm-cci.c
@@ -660,12 +660,21 @@ static void cci_pmu_del(struct perf_event *event, int flags)
}

static int
-validate_event(struct cci_pmu_hw_events *hw_events,
- struct perf_event *event)
+validate_event(struct pmu *cci_pmu,
+ struct cci_pmu_hw_events *hw_events,
+ struct perf_event *event)
{
if (is_software_event(event))
return 1;

+ /*
+ * Reject groups spanning multiple HW PMUs (e.g. CPU + CCI). The
+ * core perf code won't check that the pmu->ctx == leader->ctx
+ * until after pmu->event_init(event).
+ */
+ if (event->pmu != cci_pmu)
+ return 0;
+
if (event->state < PERF_EVENT_STATE_OFF)
return 1;

@@ -687,15 +696,15 @@ validate_group(struct perf_event *event)
.used_mask = CPU_BITS_NONE,
};

- if (!validate_event(&fake_pmu, leader))
+ if (!validate_event(event->pmu, &fake_pmu, leader))
return -EINVAL;

list_for_each_entry(sibling, &leader->sibling_list, group_entry) {
- if (!validate_event(&fake_pmu, sibling))
+ if (!validate_event(event->pmu, &fake_pmu, sibling))
return -EINVAL;
}

- if (!validate_event(&fake_pmu, event))
+ if (!validate_event(event->pmu, &fake_pmu, event))
return -EINVAL;

return 0;
--
1.7.9.5