Messages in this thread Patch in this message | | | From | Rob Herring <> | Subject | [PATCH] perf: Ignore format attributes with an unknown perf_event_attr field | Date | Thu, 1 Sep 2022 13:47:10 -0500 |
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If the kernel exposes a new perf_event_attr field in a format attr, perf will return an error stating the specified PMU can't be found. For example, a format attr with 'config3:0-63' causes an error if config3 is unknown to perf. This causes a compatibility issue between a newer kernel and an older perf tool.
The addition here makes any attr string up to the ':' ignored, but still checks the 'bits' portion.
Signed-off-by: Rob Herring <robh@kernel.org> --- This is the YACC mud I threw and seems to stick. Maybe there's a better way to handle this. It doesn't seem like there's a way to do wildcards (i.e. config.*) in YACC.
This is needed for this series[1]. Unfortunately the best we do to avoid the issue is applying this to stable. I think there's some time before v8.7 h/w is deployed, too.
Rob
[1] https://lore.kernel.org/all/20220825-arm-spe-v8-7-v1-0-c75b8d92e692@kernel.org/
tools/perf/util/pmu.y | 3 +++ 1 file changed, 3 insertions(+)
diff --git a/tools/perf/util/pmu.y b/tools/perf/util/pmu.y index bfd7e8509869..3096864ec9b9 100644 --- a/tools/perf/util/pmu.y +++ b/tools/perf/util/pmu.y @@ -60,6 +60,9 @@ PP_CONFIG2 ':' bits PERF_PMU_FORMAT_VALUE_CONFIG2, $3)); } +| +error ':' bits +{} bits: bits ',' bit_term -- 2.34.1
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