[SRU][N:gke][PATCH 067/106] perf: cs-etm: Only save valid trace IDs into files

[Tim Whisonant]

From: James Clark <james.clark at arm.com>

BugLink: https://bugs.launchpad.net/bugs/2117098

This isn't a bug because Perf always masks with
CORESIGHT_TRACE_ID_VAL_MASK before using these values, but to avoid it
looking like it could be, make an effort to not save bad values.

Reviewed-by: Mike Leach <mike.leach at linaro.org>
Signed-off-by: James Clark <james.clark at arm.com>
Signed-off-by: James Clark <james.clark at linaro.org>
Cc: Adrian Hunter <adrian.hunter at intel.com>
Cc: Alexander Shishkin <alexander.shishkin at linux.intel.com>
Cc: Alexandre Torgue <alexandre.torgue at foss.st.com>
Cc: Anshuman Khandual <anshuman.khandual at arm.com>
Cc: Ganapatrao Kulkarni <gankulkarni at os.amperecomputing.com>
Cc: Ian Rogers <irogers at google.com>
Cc: Ingo Molnar <mingo at redhat.com>
Cc: Jiri Olsa <jolsa at kernel.org>
Cc: John Garry <john.g.garry at oracle.com>
Cc: Kan Liang <kan.liang at linux.intel.com>
Cc: Leo Yan <leo.yan at linux.dev>
Cc: Mark Rutland <mark.rutland at arm.com>
Cc: Maxime Coquelin <mcoquelin.stm32 at gmail.com>
Cc: Namhyung Kim <namhyung at kernel.org>
Cc: Peter Zijlstra <peterz at infradead.org>
Cc: Suzuki Poulouse <suzuki.poulose at arm.com>
Cc: Will Deacon <will at kernel.org>
Link: https://lore.kernel.org/r/20240722101202.26915-6-james.clark@linaro.org
Signed-off-by: Arnaldo Carvalho de Melo <acme at redhat.com>
(cherry picked from commit 940007cee539fd07c7c274030f7f7252f8c5a5d7)
Signed-off-by: Tim Whisonant <tim.whisonant at canonical.com>
---
 tools/perf/arch/arm/util/cs-etm.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/tools/perf/arch/arm/util/cs-etm.c b/tools/perf/arch/arm/util/cs-etm.c
index 25c8cfd96427d..9df3fcc8609bb 100644
--- a/tools/perf/arch/arm/util/cs-etm.c
+++ b/tools/perf/arch/arm/util/cs-etm.c
@@ -634,7 +634,8 @@ static bool cs_etm_is_ete(struct auxtrace_record *itr, struct perf_cpu cpu)
 
 static __u64 cs_etm_get_legacy_trace_id(struct perf_cpu cpu)
 {
-	return CORESIGHT_LEGACY_CPU_TRACE_ID(cpu.cpu);
+	/* Wrap at 48 so that invalid trace IDs aren't saved into files. */
+	return CORESIGHT_LEGACY_CPU_TRACE_ID(cpu.cpu % 48);
 }
 
 static void cs_etm_save_etmv4_header(__u64 data[], struct auxtrace_record *itr, struct perf_cpu cpu)
-- 
2.43.0