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Diffstat (limited to 'drivers/hwtracing/coresight/coresight-etm-perf.c')
-rw-r--r--drivers/hwtracing/coresight/coresight-etm-perf.c17
1 files changed, 14 insertions, 3 deletions
diff --git a/drivers/hwtracing/coresight/coresight-etm-perf.c b/drivers/hwtracing/coresight/coresight-etm-perf.c
index 84f1dcb69827..1a3169e69bb1 100644
--- a/drivers/hwtracing/coresight/coresight-etm-perf.c
+++ b/drivers/hwtracing/coresight/coresight-etm-perf.c
@@ -226,9 +226,6 @@ static void *etm_setup_aux(struct perf_event *event, void **pages,
sink = coresight_get_enabled_sink(true);
}
- if (!sink)
- goto err;
-
mask = &event_data->mask;
/*
@@ -254,6 +251,16 @@ static void *etm_setup_aux(struct perf_event *event, void **pages,
}
/*
+ * No sink provided - look for a default sink for one of the
+ * devices. At present we only support topology where all CPUs
+ * use the same sink [N:1], so only need to find one sink. The
+ * coresight_build_path later will remove any CPU that does not
+ * attach to the sink, or if we have not found a sink.
+ */
+ if (!sink)
+ sink = coresight_find_default_sink(csdev);
+
+ /*
* Building a path doesn't enable it, it simply builds a
* list of devices from source to sink that can be
* referenced later when the path is actually needed.
@@ -267,6 +274,10 @@ static void *etm_setup_aux(struct perf_event *event, void **pages,
*etm_event_cpu_path_ptr(event_data, cpu) = path;
}
+ /* no sink found for any CPU - cannot trace */
+ if (!sink)
+ goto err;
+
/* If we don't have any CPUs ready for tracing, abort */
cpu = cpumask_first(mask);
if (cpu >= nr_cpu_ids)