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authorLeo Yan <[email protected]>2018-07-11 15:45:42 +0800
committerArnaldo Carvalho de Melo <[email protected]>2018-07-31 10:57:56 -0300
commit3eb3e07bcfee0670d7142f839c76f33f3d265793 (patch)
tree0a3db926a737671ff0189b910a532bf43a462676
parent83868bf71d2eb7700b37f1ea188007f0125e4ee4 (diff)
perf cs-etm: Fix start tracing packet handling
Usually the start tracing packet is a CS_ETM_TRACE_ON packet, this packet is passed to cs_etm__flush(); cs_etm__flush() will check the condition 'prev_packet->sample_type == CS_ETM_RANGE' but 'prev_packet' is allocated by zalloc() so 'prev_packet->sample_type' is zero in initialization and this condition is false. So cs_etm__flush() will directly bail out without handling the start tracing packet. This patch is to introduce a new sample type CS_ETM_EMPTY, which is used to indicate the packet is an empty packet. cs_etm__flush() will swap packets when it finds the previous packet is empty, so this can record the start tracing packet into 'etmq->prev_packet'. Signed-off-by: Leo Yan <[email protected]> Reviewed-by: Mathieu Poirier <[email protected]> Cc: Alexander Shishkin <[email protected]> Cc: Jiri Olsa <[email protected]> Cc: Kim Phillips <[email protected]> Cc: Mike Leach <[email protected]> Cc: Namhyung Kim <[email protected]> Cc: Peter Zijlstra <[email protected]> Cc: Robert Walker <[email protected]> Cc: [email protected] Link: http://lkml.kernel.org/r/[email protected] Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>
-rw-r--r--tools/perf/util/cs-etm-decoder/cs-etm-decoder.h1
-rw-r--r--tools/perf/util/cs-etm.c19
2 files changed, 19 insertions, 1 deletions
diff --git a/tools/perf/util/cs-etm-decoder/cs-etm-decoder.h b/tools/perf/util/cs-etm-decoder/cs-etm-decoder.h
index 743f5f444304..612b5755f742 100644
--- a/tools/perf/util/cs-etm-decoder/cs-etm-decoder.h
+++ b/tools/perf/util/cs-etm-decoder/cs-etm-decoder.h
@@ -23,6 +23,7 @@ struct cs_etm_buffer {
};
enum cs_etm_sample_type {
+ CS_ETM_EMPTY = 0,
CS_ETM_RANGE = 1 << 0,
CS_ETM_TRACE_ON = 1 << 1,
};
diff --git a/tools/perf/util/cs-etm.c b/tools/perf/util/cs-etm.c
index 8b2c099e750a..ae7c9c880cb2 100644
--- a/tools/perf/util/cs-etm.c
+++ b/tools/perf/util/cs-etm.c
@@ -924,8 +924,14 @@ static int cs_etm__flush(struct cs_etm_queue *etmq)
int err = 0;
struct cs_etm_packet *tmp;
+ if (!etmq->prev_packet)
+ return 0;
+
+ /* Handle start tracing packet */
+ if (etmq->prev_packet->sample_type == CS_ETM_EMPTY)
+ goto swap_packet;
+
if (etmq->etm->synth_opts.last_branch &&
- etmq->prev_packet &&
etmq->prev_packet->sample_type == CS_ETM_RANGE) {
/*
* Generate a last branch event for the branches left in the
@@ -944,6 +950,10 @@ static int cs_etm__flush(struct cs_etm_queue *etmq)
etmq->period_instructions = 0;
+ }
+
+swap_packet:
+ if (etmq->etm->synth_opts.last_branch) {
/*
* Swap PACKET with PREV_PACKET: PACKET becomes PREV_PACKET for
* the next incoming packet.
@@ -1023,6 +1033,13 @@ static int cs_etm__run_decoder(struct cs_etm_queue *etmq)
*/
cs_etm__flush(etmq);
break;
+ case CS_ETM_EMPTY:
+ /*
+ * Should not receive empty packet,
+ * report error.
+ */
+ pr_err("CS ETM Trace: empty packet\n");
+ return -EINVAL;
default:
break;
}