[PATCH v2 1/2] perf: tools: cs-etm: Fix print issue for Coresight debug in ETE/TRBE trace

From: Mike Leach

Date: Wed Mar 18 2026 - 06:36:59 EST


Building perf with CORESIGHT=1 and the optional CSTRACE_RAW=1 enables
additional debug printing of raw trace data when using command:-
perf report --dump.

This raw trace prints the CoreSight formatted trace frames, which may be
used to investigate suspected issues with trace quality / corruption /
decode.

These frames are not present in ETE + TRBE trace.
This fix removes the unnecessary call to print these frames.

This fix also rationalises implementation - original code had helper
function that unnecessarily repeated initialisation calls that had
already been made.

Due to an addtional fault with the OpenCSD library, this call when ETE/TRBE
are being decoded will cause a segfault in perf. This fix also prevents
that problem for perf using older (<= 1.8.0 version) OpenCSD libraries.

Fixes: 68ffe3902898 ("perf tools: Add decoder mechanic to support dumping trace data")
Reported-by: Leo Yan <leo.yan@xxxxxxx>
Signed-off-by: Mike Leach <mike.leach@xxxxxxx>
---
Changes in v2: Rationalise implementation
---
.../perf/util/cs-etm-decoder/cs-etm-decoder.c | 51 +++++--------------
1 file changed, 13 insertions(+), 38 deletions(-)

diff --git a/tools/perf/util/cs-etm-decoder/cs-etm-decoder.c b/tools/perf/util/cs-etm-decoder/cs-etm-decoder.c
index 3050fe212666..8592a778b26a 100644
--- a/tools/perf/util/cs-etm-decoder/cs-etm-decoder.c
+++ b/tools/perf/util/cs-etm-decoder/cs-etm-decoder.c
@@ -237,46 +237,24 @@ cs_etm_decoder__init_def_logger_printing(struct cs_etm_decoder_params *d_params,
(void *)decoder,
cs_etm_decoder__print_str_cb);
if (ret != 0)
- ret = -1;
-
- return 0;
-}
+ return -1;

#ifdef CS_LOG_RAW_FRAMES
-static void
-cs_etm_decoder__init_raw_frame_logging(struct cs_etm_decoder_params *d_params,
- struct cs_etm_decoder *decoder)
-{
- /* Only log these during a --dump operation */
- if (d_params->operation == CS_ETM_OPERATION_PRINT) {
- /* set up a library default logger to process the
- * raw frame printer we add later
- */
- ocsd_def_errlog_init(OCSD_ERR_SEV_ERROR, 1);
-
- /* no stdout / err / file output */
- ocsd_def_errlog_config_output(C_API_MSGLOGOUT_FLG_NONE, NULL);
-
- /* set the string CB for the default logger,
- * passes strings to perf print logger.
- */
- ocsd_def_errlog_set_strprint_cb(decoder->dcd_tree,
- (void *)decoder,
- cs_etm_decoder__print_str_cb);
-
+ /*
+ * Only log raw frames if --dump operation and hardware is actually
+ * generating formatted CoreSight trace frames
+ */
+ if ((d_params->operation == CS_ETM_OPERATION_PRINT) &&
+ (d_params->formatted == true)) {
/* use the built in library printer for the raw frames */
- ocsd_dt_set_raw_frame_printer(decoder->dcd_tree,
- CS_RAW_DEBUG_FLAGS);
+ ret = ocsd_dt_set_raw_frame_printer(decoder->dcd_tree,
+ CS_RAW_DEBUG_FLAGS);
+ if (ret != 0)
+ return -1;
}
-}
-#else
-static void
-cs_etm_decoder__init_raw_frame_logging(
- struct cs_etm_decoder_params *d_params __maybe_unused,
- struct cs_etm_decoder *decoder __maybe_unused)
-{
-}
#endif
+ return 0;
+}

static ocsd_datapath_resp_t
cs_etm_decoder__do_soft_timestamp(struct cs_etm_queue *etmq,
@@ -738,9 +716,6 @@ cs_etm_decoder__new(int decoders, struct cs_etm_decoder_params *d_params,
if (ret != 0)
goto err_free_decoder;

- /* init raw frame logging if required */
- cs_etm_decoder__init_raw_frame_logging(d_params, decoder);
-
for (i = 0; i < decoders; i++) {
ret = cs_etm_decoder__create_etm_decoder(d_params,
&t_params[i],
--
2.43.0