4.20-stable review patch. If anyone has any objections, please let me know.
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[ Upstream commit 1c6f709b9f96366cc47af23c05ecec9b8c0c392d ]
Users should never use 'pt=0', but if they do it may give a meaningless error:
$ perf record -e intel_pt/pt=0/u uname Error: The sys_perf_event_open() syscall returned with 22 (Invalid argument) for event (intel_pt/pt=0/u).
Fix that by forcing 'pt=1'.
Committer testing:
# perf record -e intel_pt/pt=0/u uname Error: The sys_perf_event_open() syscall returned with 22 (Invalid argument) for event (intel_pt/pt=0/u). /bin/dmesg | grep -i perf may provide additional information.
# perf record -e intel_pt/pt=0/u uname pt=0 doesn't make sense, forcing pt=1 Linux [ perf record: Woken up 1 times to write data ] [ perf record: Captured and wrote 0.020 MB perf.data ] #
Signed-off-by: Adrian Hunter adrian.hunter@intel.com Tested-by: Arnaldo Carvalho de Melo acme@redhat.com Cc: Jiri Olsa jolsa@redhat.com Link: http://lkml.kernel.org/r/b7c5b4e5-9497-10e5-fd43-5f3e4a0fe51d@intel.com Signed-off-by: Arnaldo Carvalho de Melo acme@redhat.com Signed-off-by: Sasha Levin sashal@kernel.org --- tools/perf/arch/x86/util/intel-pt.c | 11 +++++++++++ 1 file changed, 11 insertions(+)
diff --git a/tools/perf/arch/x86/util/intel-pt.c b/tools/perf/arch/x86/util/intel-pt.c index db0ba8caf5a2..ba8ecaf52200 100644 --- a/tools/perf/arch/x86/util/intel-pt.c +++ b/tools/perf/arch/x86/util/intel-pt.c @@ -524,10 +524,21 @@ static int intel_pt_validate_config(struct perf_pmu *intel_pt_pmu, struct perf_evsel *evsel) { int err; + char c;
if (!evsel) return 0;
+ /* + * If supported, force pass-through config term (pt=1) even if user + * sets pt=0, which avoids senseless kernel errors. + */ + if (perf_pmu__scan_file(intel_pt_pmu, "format/pt", "%c", &c) == 1 && + !(evsel->attr.config & 1)) { + pr_warning("pt=0 doesn't make sense, forcing pt=1\n"); + evsel->attr.config |= 1; + } + err = intel_pt_val_config_term(intel_pt_pmu, "caps/cycle_thresholds", "cyc_thresh", "caps/psb_cyc", evsel->attr.config);