perf pmu: "Compat" supports regular expression matching identifiers

The jevent "Compat" is used for uncore PMU alias or metric definitions.

The same PMU driver has different PMU identifiers due to different
hardware versions and types, but they may have some common PMU event.
Since a Compat value can only match one identifier, when adding the
same event alias to PMUs with different identifiers, each identifier
needs to be defined once, which is not streamlined enough.

So let "Compat" support using regular expression to match identifiers
for uncore PMU alias. For example, if the "Compat" value is set to
"43401|43c01", it would be able to match PMU identifiers such as "43401"
or "43c01", which correspond to CMN600_r0p0 or CMN700_r0p0.
Signed-off-by: Jing Zhang <renyu.zj@linux.alibaba.com>
Reviewed-by: Ian Rogers <irogers@google.com>
Tested-by: Ian Rogers <irogers@google.com>
Cc: James Clark <james.clark@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Leo Yan <leo.yan@linaro.org>
Cc: Mike Leach <mike.leach@linaro.org>
Cc: Shuai Xue <xueshuai@linux.alibaba.com>
Cc: Zhuo Song <zhuo.song@linux.alibaba.com>
Cc: John Garry <john.g.garry@oracle.com>
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-doc@vger.kernel.org
Link: https://lore.kernel.org/r/1695794391-34817-2-git-send-email-renyu.zj@linux.alibaba.comSigned-off-by: Namhyung Kim <namhyung@kernel.org>

tools/perf/util/pmu.c

@@ -28,6 +28,7 @@
 #include "strbuf.h"
 #include "fncache.h"
 #include "util/evsel_config.h"
+#include <regex.h>
 
 struct perf_pmu perf_pmu__fake = {
 	.name = "fake",
@@ -870,6 +871,28 @@ static bool pmu_uncore_alias_match(const char *pmu_name, const char *name)
 	return res;
 }
 
+bool pmu_uncore_identifier_match(const char *compat, const char *id)
+{
+	regex_t re;
+	regmatch_t pmatch[1];
+	int match;
+
+	if (regcomp(&re, compat, REG_EXTENDED) != 0) {
+		/* Warn unable to generate match particular string. */
+		pr_info("Invalid regular expression %s\n", compat);
+		return false;
+	}
+
+	match = !regexec(&re, id, 1, pmatch, 0);
+	if (match) {
+		/* Ensure a full match. */
+		match = pmatch[0].rm_so == 0 && (size_t)pmatch[0].rm_eo == strlen(id);
+	}
+	regfree(&re);
+
+	return match;
+}
+
 static int pmu_add_cpu_aliases_map_callback(const struct pmu_event *pe,
 					const struct pmu_events_table *table __maybe_unused,
 					void *vdata)
@@ -910,8 +933,8 @@ static int pmu_add_sys_aliases_iter_fn(const struct pmu_event *pe,
 	if (!pe->compat || !pe->pmu)
 		return 0;
 
-	if (!strcmp(pmu->id, pe->compat) &&
-	    pmu_uncore_alias_match(pe->pmu, pmu->name)) {
+	if (pmu_uncore_alias_match(pe->pmu, pmu->name) &&
+			pmu_uncore_identifier_match(pe->compat, pmu->id)) {
 		perf_pmu__new_alias(pmu,
 				pe->name,
 				pe->desc,

tools/perf/util/pmu.h

@@ -239,6 +239,7 @@ void pmu_add_cpu_aliases_table(struct perf_pmu *pmu,
 
 char *perf_pmu__getcpuid(struct perf_pmu *pmu);
 const struct pmu_metrics_table *pmu_metrics_table__find(void);
+bool pmu_uncore_identifier_match(const char *compat, const char *id);
 
 int perf_pmu__convert_scale(const char *scale, char **end, double *sval);