From: Al Grant al.grant@arm.com
[ Upstream commit a347306fbec5dcaf7c276777b11d530eab6a4526 ]
Commit 42bbabed09ce6208 ("perf tools: Add hw_idx in struct branch_stack") changed the format of branch stacks in perf samples. When samples use this new format, a flag must be set in the corresponding event.
Synthesized branch stacks generated from Intel PT were using the new format, but not setting the event attribute, leading to consumers seeing corrupt data. This patch fixes the issue by setting the event attribute to indicate use of the new format.
Fixes: 42bbabed09ce6208 ("perf tools: Add hw_idx in struct branch_stack") Signed-off-by: Al Grant al.grant@arm.com Acked-by: Adrian Hunter adrian.hunter@intel.com Reviewed-by: Mathieu Poirier mathieu.poirier@linaro.org Cc: Alexander Shishkin alexander.shishkin@linux.intel.com Cc: Andi Kleen ak@linux.intel.com Cc: Jiri Olsa jolsa@redhat.com Cc: Kan Liang kan.liang@linux.intel.com Cc: Leo Yan leo.yan@linaro.org Cc: Mark Rutland mark.rutland@arm.com Cc: Mike Leach mike.leach@linaro.org Cc: Namhyung Kim namhyung@kernel.org Cc: Peter Zijlstra peterz@infradead.org Cc: Suzuki Poulouse suzuki.poulose@arm.com Cc: linux-arm-kernel@lists.infradead.org Link: http://lore.kernel.org/lkml/20200819084751.17686-2-leo.yan@linaro.org Signed-off-by: Leo Yan leo.yan@linaro.org Signed-off-by: Arnaldo Carvalho de Melo acme@redhat.com Signed-off-by: Sasha Levin sashal@kernel.org --- tools/perf/util/intel-pt.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-)
diff --git a/tools/perf/util/intel-pt.c b/tools/perf/util/intel-pt.c index cb3c1e569a2db..9357b5f62c273 100644 --- a/tools/perf/util/intel-pt.c +++ b/tools/perf/util/intel-pt.c @@ -2913,8 +2913,15 @@ static int intel_pt_synth_events(struct intel_pt *pt,
if (pt->synth_opts.callchain) attr.sample_type |= PERF_SAMPLE_CALLCHAIN; - if (pt->synth_opts.last_branch) + if (pt->synth_opts.last_branch) { attr.sample_type |= PERF_SAMPLE_BRANCH_STACK; + /* + * We don't use the hardware index, but the sample generation + * code uses the new format branch_stack with this field, + * so the event attributes must indicate that it's present. + */ + attr.branch_sample_type |= PERF_SAMPLE_BRANCH_HW_INDEX; + }
if (pt->synth_opts.instructions) { attr.config = PERF_COUNT_HW_INSTRUCTIONS;