[PATCH 5.19 696/717] perf: Skip and warn on unknown format configN attrs

Greg Kroah-Hartman
2022-10-22T08:50:42Z

From: Rob Herring <robh@kernel.org>

commit e552b7be12ed62357df84392efa525ecb01910fb upstream.

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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
tools/perf/util/parse-events.c | 3 +++
tools/perf/util/pmu.c | 17 +++++++++++++++++
tools/perf/util/pmu.h | 2 ++
tools/perf/util/pmu.l | 2 --
tools/perf/util/pmu.y | 15 ++++-----------
5 files changed, 26 insertions(+), 13 deletions(-)

--- a/tools/perf/util/parse-events.c
+++ b/tools/perf/util/parse-events.c
@@ -255,6 +255,9 @@ __add_event(struct list_head *list, int
struct perf_cpu_map *cpus = pmu ? perf_cpu_map__get(pmu->cpus) :
cpu_list ? perf_cpu_map__new(cpu_list) : NULL;

+ if (pmu)
+ perf_pmu__warn_invalid_formats(pmu);
+
if (pmu && attr->type == PERF_TYPE_RAW)
perf_pmu__warn_invalid_config(pmu, attr->config, name);

--- a/tools/perf/util/pmu.c
+++ b/tools/perf/util/pmu.c
@@ -1048,6 +1048,23 @@ err:
return NULL;
}

+void perf_pmu__warn_invalid_formats(struct perf_pmu *pmu)
+{
+ struct perf_pmu_format *format;
+
+ /* fake pmu doesn't have format list */
+ if (pmu == &perf_pmu__fake)
+ return;
+
+ list_for_each_entry(format, &pmu->format, list)
+ if (format->value >= PERF_PMU_FORMAT_VALUE_CONFIG_END) {
+ pr_warning("WARNING: '%s' format '%s' requires 'perf_event_attr::config%d'"
+ "which is not supported by this version of perf!\n",
+ pmu->name, format->name, format->value);
+ return;
+ }
+}
+
static struct perf_pmu *pmu_find(const char *name)
{
struct perf_pmu *pmu;
--- a/tools/perf/util/pmu.h
+++ b/tools/perf/util/pmu.h
@@ -17,6 +17,7 @@ enum {
PERF_PMU_FORMAT_VALUE_CONFIG,
PERF_PMU_FORMAT_VALUE_CONFIG1,
PERF_PMU_FORMAT_VALUE_CONFIG2,
+ PERF_PMU_FORMAT_VALUE_CONFIG_END,
};

#define PERF_PMU_FORMAT_BITS 64
@@ -139,6 +140,7 @@ int perf_pmu__caps_parse(struct perf_pmu

void perf_pmu__warn_invalid_config(struct perf_pmu *pmu, __u64 config,
const char *name);
+void perf_pmu__warn_invalid_formats(struct perf_pmu *pmu);

bool perf_pmu__has_hybrid(void);
int perf_pmu__match(char *pattern, char *name, char *tok);
--- a/tools/perf/util/pmu.l
+++ b/tools/perf/util/pmu.l
@@ -27,8 +27,6 @@ num_dec [0-9]+

{num_dec} { return value(10); }
config { return PP_CONFIG; }
-config1 { return PP_CONFIG1; }
-config2 { return PP_CONFIG2; }
- { return '-'; }
: { return ':'; }
, { return ','; }
--- a/tools/perf/util/pmu.y
+++ b/tools/perf/util/pmu.y
@@ -20,7 +20,7 @@ do { \

%}

-%token PP_CONFIG PP_CONFIG1 PP_CONFIG2
+%token PP_CONFIG
%token PP_VALUE PP_ERROR
%type <num> PP_VALUE
%type <bits> bit_term
@@ -47,18 +47,11 @@ PP_CONFIG ':' bits
$3));
}
|
-PP_CONFIG1 ':' bits
+PP_CONFIG PP_VALUE ':' bits
{
ABORT_ON(perf_pmu__new_format(format, name,
- PERF_PMU_FORMAT_VALUE_CONFIG1,
- $3));
-}
-|
-PP_CONFIG2 ':' bits
-{
- ABORT_ON(perf_pmu__new_format(format, name,
- PERF_PMU_FORMAT_VALUE_CONFIG2,
- $3));
+ $2,
+ $4));
}