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Diffstat (limited to 'arch/arm64/kernel/perf_event.c')
-rw-r--r--arch/arm64/kernel/perf_event.c8
1 files changed, 8 insertions, 0 deletions
diff --git a/arch/arm64/kernel/perf_event.c b/arch/arm64/kernel/perf_event.c
index 3e43538f6b72..dde06c0f97f3 100644
--- a/arch/arm64/kernel/perf_event.c
+++ b/arch/arm64/kernel/perf_event.c
@@ -1063,6 +1063,14 @@ static int __armv8_pmuv3_map_event(struct perf_event *event,
&armv8_pmuv3_perf_cache_map,
ARMV8_PMU_EVTYPE_EVENT);
+ /*
+ * CHAIN events only work when paired with an adjacent counter, and it
+ * never makes sense for a user to open one in isolation, as they'll be
+ * rotated arbitrarily.
+ */
+ if (hw_event_id == ARMV8_PMUV3_PERFCTR_CHAIN)
+ return -EINVAL;
+
if (armv8pmu_event_is_64bit(event))
event->hw.flags |= ARMPMU_EVT_64BIT;