diff options
| -rw-r--r-- | drivers/hwtracing/coresight/coresight-etm-perf.c | 60 |
1 files changed, 52 insertions, 8 deletions
diff --git a/drivers/hwtracing/coresight/coresight-etm-perf.c b/drivers/hwtracing/coresight/coresight-etm-perf.c index 0f603b4094f2..aa0974bd265b 100644 --- a/drivers/hwtracing/coresight/coresight-etm-perf.c +++ b/drivers/hwtracing/coresight/coresight-etm-perf.c @@ -232,6 +232,25 @@ static void etm_free_aux(void *data) schedule_work(&event_data->work); } +/* + * Check if two given sinks are compatible with each other, + * so that they can use the same sink buffers, when an event + * moves around. + */ +static bool sinks_compatible(struct coresight_device *a, + struct coresight_device *b) +{ + if (!a || !b) + return false; + /* + * If the sinks are of the same subtype and driven + * by the same driver, we can use the same buffer + * on these sinks. + */ + return (a->subtype.sink_subtype == b->subtype.sink_subtype) && + (sink_ops(a) == sink_ops(b)); +} + static void *etm_setup_aux(struct perf_event *event, void **pages, int nr_pages, bool overwrite) { @@ -239,6 +258,7 @@ static void *etm_setup_aux(struct perf_event *event, void **pages, int cpu = event->cpu; cpumask_t *mask; struct coresight_device *sink = NULL; + struct coresight_device *user_sink = NULL, *last_sink = NULL; struct etm_event_data *event_data = NULL; event_data = alloc_event_data(cpu); @@ -249,7 +269,7 @@ static void *etm_setup_aux(struct perf_event *event, void **pages, /* First get the selected sink from user space. */ if (event->attr.config2) { id = (u32)event->attr.config2; - sink = coresight_get_sink_by_id(id); + sink = user_sink = coresight_get_sink_by_id(id); } mask = &event_data->mask; @@ -277,14 +297,33 @@ 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. + * No sink provided - look for a default sink for all the ETMs, + * where this event can be scheduled. + * We allocate the sink specific buffers only once for this + * event. If the ETMs have different default sink devices, we + * can only use a single "type" of sink as the event can carry + * only one sink specific buffer. Thus we have to make sure + * that the sinks are of the same type and driven by the same + * driver, as the one we allocate the buffer for. As such + * we choose the first sink and check if the remaining ETMs + * have a compatible default sink. We don't trace on a CPU + * if the sink is not compatible. */ - if (!sink) + if (!user_sink) { + /* Find the default sink for this ETM */ sink = coresight_find_default_sink(csdev); + if (!sink) { + cpumask_clear_cpu(cpu, mask); + continue; + } + + /* Check if this sink compatible with the last sink */ + if (last_sink && !sinks_compatible(last_sink, sink)) { + cpumask_clear_cpu(cpu, mask); + continue; + } + last_sink = sink; + } /* * Building a path doesn't enable it, it simply builds a @@ -312,7 +351,12 @@ static void *etm_setup_aux(struct perf_event *event, void **pages, if (!sink_ops(sink)->alloc_buffer || !sink_ops(sink)->free_buffer) goto err; - /* Allocate the sink buffer for this session */ + /* + * Allocate the sink buffer for this session. All the sinks + * where this event can be scheduled are ensured to be of the + * same type. Thus the same sink configuration is used by the + * sinks. + */ event_data->snk_config = sink_ops(sink)->alloc_buffer(sink, event, pages, nr_pages, overwrite); |