linux/tools/perf/util/pmu.l
Rob Herring e552b7be12 perf: Skip and warn on unknown format 'configN' attrs
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 as config3 is
unknown to perf. This causes a compatibility issue between a newer
kernel with older perf tool.

Before this change with a kernel adding 'config3' I get:

  $ perf record -e arm_spe// -- true
  event syntax error: 'arm_spe//'
                       \___ Cannot find PMU `arm_spe'. Missing kernel support?
  Run 'perf list' for a list of valid events

   Usage: perf record [<options>] [<command>]
      or: perf record [<options>] -- <command> [<options>]

      -e, --event <event>   event selector. use 'perf list' to list
  available events

After this change, I get:

  $ perf record -e arm_spe// -- true
  WARNING: 'arm_spe_0' format 'inv_event_filter' requires 'perf_event_attr::config3' which is not supported by this version of perf!
  [ perf record: Woken up 2 times to write data ]
  [ perf record: Captured and wrote 0.091 MB perf.data ]

To support unknown configN formats, rework the YACC implementation to
pass any config[0-9]+ format to perf_pmu__new_format() to handle with a
warning.

Reviewed-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Rob Herring <robh@kernel.org>
Tested-by: Leo Yan <leo.yan@linaro.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: James Clark <james.clark@arm.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20220914-arm-perf-tool-spe1-2-v2-v4-1-83c098e6212e@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2022-10-14 12:23:09 -03:00

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%option prefix="perf_pmu_"
%{
#include <stdlib.h>
#include <linux/bitops.h>
#include "pmu.h"
#include "pmu-bison.h"
static int value(int base)
{
long num;
errno = 0;
num = strtoul(perf_pmu_text, NULL, base);
if (errno)
return PP_ERROR;
perf_pmu_lval.num = num;
return PP_VALUE;
}
%}
num_dec [0-9]+
%%
{num_dec} { return value(10); }
config { return PP_CONFIG; }
- { return '-'; }
: { return ':'; }
, { return ','; }
. { ; }
\n { ; }
%%
int perf_pmu_wrap(void)
{
return 1;
}