linux-kernel - [PATCH 5.7 073/166] perf intel-pt: Fix recording PEBS-via-PT with registers

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Date:   Tue, 14 Jul 2020 20:43:58 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Adrian Hunter <adrian.hunter@...el.com>,
        Jiri Olsa <jolsa@...hat.com>,
        Luwei Kang <luwei.kang@...el.com>,
        Arnaldo Carvalho de Melo <acme@...hat.com>,
        Sasha Levin <sashal@...nel.org>
Subject: [PATCH 5.7 073/166] perf intel-pt: Fix recording PEBS-via-PT with registers

From: Adrian Hunter <adrian.hunter@...el.com>

[ Upstream commit 75bcb8776dc987538f267ba4ba05ca43fc2b1676 ]

When recording PEBS-via-PT, the kernel will not accept the intel_pt
event with register sampling e.g.

 # perf record --kcore -c 10000 -e '{intel_pt/branch=0/,branch-loads/aux-output/ppp}' -I -- ls -l
 Error:
 intel_pt/branch=0/: PMU Hardware doesn't support sampling/overflow-interrupts. Try 'perf stat'

Fix by suppressing register sampling on the intel_pt evsel.

Committer notes:

Adrian informed that this is only available from Tremont onwards, so on
older processors the error continues the same as before.

Fixes: 9e64cefe4335b ("perf intel-pt: Process options for PEBS event synthesis")
Signed-off-by: Adrian Hunter <adrian.hunter@...el.com>
Cc: Jiri Olsa <jolsa@...hat.com>
Cc: Luwei Kang <luwei.kang@...el.com>
Link: http://lore.kernel.org/lkml/20200630133935.11150-2-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@...hat.com>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 tools/perf/arch/x86/util/intel-pt.c | 1 +
 tools/perf/util/evsel.c             | 4 ++--
 2 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/tools/perf/arch/x86/util/intel-pt.c b/tools/perf/arch/x86/util/intel-pt.c
index 1643aed8c4c8e..2a548fbdf2a2a 100644
--- a/tools/perf/arch/x86/util/intel-pt.c
+++ b/tools/perf/arch/x86/util/intel-pt.c
@@ -634,6 +634,7 @@ static int intel_pt_recording_options(struct auxtrace_record *itr,
 			}
 			evsel->core.attr.freq = 0;
 			evsel->core.attr.sample_period = 1;
+			evsel->no_aux_samples = true;
 			intel_pt_evsel = evsel;
 			opts->full_auxtrace = true;
 		}
diff --git a/tools/perf/util/evsel.c b/tools/perf/util/evsel.c
index eb880efbce16d..386950f29792a 100644
--- a/tools/perf/util/evsel.c
+++ b/tools/perf/util/evsel.c
@@ -1048,12 +1048,12 @@ void perf_evsel__config(struct evsel *evsel, struct record_opts *opts,
 	if (callchain && callchain->enabled && !evsel->no_aux_samples)
 		perf_evsel__config_callchain(evsel, opts, callchain);
 
-	if (opts->sample_intr_regs) {
+	if (opts->sample_intr_regs && !evsel->no_aux_samples) {
 		attr->sample_regs_intr = opts->sample_intr_regs;
 		perf_evsel__set_sample_bit(evsel, REGS_INTR);
 	}
 
-	if (opts->sample_user_regs) {
+	if (opts->sample_user_regs && !evsel->no_aux_samples) {
 		attr->sample_regs_user |= opts->sample_user_regs;
 		perf_evsel__set_sample_bit(evsel, REGS_USER);
 	}
-- 
2.25.1