[PATCH] ARC: perf: ARC 700 PMU doesn't support sampling events

[Mischa Jonker]

The ARC 700 does not have an interrupt associated with it, and as
such it cannot trigger when a counter overflows. As the counters are
48 bit, it will usually take at least 100 days before a counter
overflows, so for mere counting of events, there is no problem.
Sampling is not supported though.

Cc: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
Cc: Vineet Gupta <vgupta@xxxxxxxxxxxx>
Signed-off-by: Mischa Jonker <mjonker@xxxxxxxxxxxx>
---
 arch/arc/kernel/perf_event.c |    4 ++++
 1 file changed, 4 insertions(+)

diff --git a/arch/arc/kernel/perf_event.c b/arch/arc/kernel/perf_event.c
index 759e5f3..e46d81f 100644
--- a/arch/arc/kernel/perf_event.c
+++ b/arch/arc/kernel/perf_event.c
@@ -99,6 +99,10 @@ static int arc_pmu_event_init(struct perf_event *event)
 	struct hw_perf_event *hwc = &event->hw;
 	int ret;
 
+	/* ARC 700 PMU does not support sampling events */
+	if (is_sampling_event(event))
+		return -ENOENT;
+
 	switch (event->attr.type) {
 	case PERF_TYPE_HARDWARE:
 		if (event->attr.config >= PERF_COUNT_HW_MAX)
-- 
1.7.9.5

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