perf pmu: Remove logic for PMU name being NULL

The PMU name could be NULL in the case of the fake_pmu. Initialize the
name for the fake_pmu to "fake" so that all other logic can assume it
is initialized. Add a const to the type of name so that a literal can
be used to avoid additional initialization code. Propagate the cost
through related routines and remove now unnecessary "(char *)"
casts. Doing this located a bug in builtin-list for the pmu_glob that
was missing a strdup.

Signed-off-by: Ian Rogers <irogers@google.com>
Link: https://lore.kernel.org/r/20230825024002.801955-3-irogers@google.com
Cc: K Prateek Nayak <kprateek.nayak@amd.com>
Cc: Ravi Bangoria <ravi.bangoria@amd.com>
Cc: James Clark <james.clark@arm.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Suzuki Poulouse <suzuki.poulose@arm.com>
Cc: Sean Christopherson <seanjc@google.com>
Cc: Wei Li <liwei391@huawei.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Huacai Chen <chenhuacai@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Will Deacon <will@kernel.org>
Cc: Leo Yan <leo.yan@linaro.org>
Cc: Mike Leach <mike.leach@linaro.org>
Cc: Kajol Jain <kjain@linux.ibm.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Athira Rajeev <atrajeev@linux.vnet.ibm.com>
Cc: linux-arm-kernel@lists.infradead.org
Cc: Ming Wang <wangming01@loongson.cn>
Cc: John Garry <john.g.garry@oracle.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: linux-kernel@vger.kernel.org
Cc: linux-perf-users@vger.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

4 files changed, 13 insertions, 13 deletions

diff --git a/tools/perf/arch/arm64/util/mem-events.c b/tools/perf/arch/arm64/util/mem-events.c
index df817d1f9f3e..3bcc5c7035c2 100644
--- a/tools/perf/arch/arm64/util/mem-events.c
+++ b/tools/perf/arch/arm64/util/mem-events.c
@@ -20,7 +20,7 @@ struct perf_mem_event *perf_mem_events__ptr(int i)
 	return &perf_mem_events[i];
 }
 
-char *perf_mem_events__name(int i, char *pmu_name __maybe_unused)
+const char *perf_mem_events__name(int i, const char *pmu_name __maybe_unused)
 {
 	struct perf_mem_event *e = perf_mem_events__ptr(i);
 
diff --git a/tools/perf/arch/powerpc/util/mem-events.c b/tools/perf/arch/powerpc/util/mem-events.c
index 4120fafe0be4..78b986e5268d 100644
--- a/tools/perf/arch/powerpc/util/mem-events.c
+++ b/tools/perf/arch/powerpc/util/mem-events.c
@@ -3,10 +3,10 @@
 #include "mem-events.h"
 
 /* PowerPC does not support 'ldlat' parameter. */
-char *perf_mem_events__name(int i, char *pmu_name __maybe_unused)
+const char *perf_mem_events__name(int i, const char *pmu_name __maybe_unused)
 {
 	if (i == PERF_MEM_EVENTS__LOAD)
-		return (char *) "cpu/mem-loads/";
+		return "cpu/mem-loads/";
 
-	return (char *) "cpu/mem-stores/";
+	return "cpu/mem-stores/";
 }
diff --git a/tools/perf/arch/x86/util/mem-events.c b/tools/perf/arch/x86/util/mem-events.c
index a8a782bcb121..191b372f9a2d 100644
--- a/tools/perf/arch/x86/util/mem-events.c
+++ b/tools/perf/arch/x86/util/mem-events.c
@@ -52,7 +52,7 @@ bool is_mem_loads_aux_event(struct evsel *leader)
 	return leader->core.attr.config == MEM_LOADS_AUX;
 }
 
-char *perf_mem_events__name(int i, char *pmu_name)
+const char *perf_mem_events__name(int i, const char *pmu_name)
 {
 	struct perf_mem_event *e = perf_mem_events__ptr(i);
 
@@ -65,7 +65,7 @@ char *perf_mem_events__name(int i, char *pmu_name)
 
 		if (!pmu_name) {
 			mem_loads_name__init = true;
-			pmu_name = (char *)"cpu";
+			pmu_name = "cpu";
 		}
 
 		if (perf_pmus__have_event(pmu_name, "mem-loads-aux")) {
@@ -82,12 +82,12 @@ char *perf_mem_events__name(int i, char *pmu_name)
 
 	if (i == PERF_MEM_EVENTS__STORE) {
 		if (!pmu_name)
-			pmu_name = (char *)"cpu";
+			pmu_name = "cpu";
 
 		scnprintf(mem_stores_name, sizeof(mem_stores_name),
 			  e->name, pmu_name);
 		return mem_stores_name;
 	}
 
-	return (char *)e->name;
+	return e->name;
 }
diff --git a/tools/perf/arch/x86/util/pmu.c b/tools/perf/arch/x86/util/pmu.c
index 65d8cdff4d5f..f428cffb0378 100644
--- a/tools/perf/arch/x86/util/pmu.c
+++ b/tools/perf/arch/x86/util/pmu.c
@@ -126,7 +126,7 @@ close_dir:
 	return ret;
 }
 
-static char *__pmu_find_real_name(const char *name)
+static const char *__pmu_find_real_name(const char *name)
 {
 	struct pmu_alias *pmu_alias;
 
@@ -135,10 +135,10 @@ static char *__pmu_find_real_name(const char *name)
 			return pmu_alias->name;
 	}
 
-	return (char *)name;
+	return name;
 }
 
-char *pmu_find_real_name(const char *name)
+const char *pmu_find_real_name(const char *name)
 {
 	if (cached_list)
 		return __pmu_find_real_name(name);
@@ -149,7 +149,7 @@ char *pmu_find_real_name(const char *name)
 	return __pmu_find_real_name(name);
 }
 
-static char *__pmu_find_alias_name(const char *name)
+static const char *__pmu_find_alias_name(const char *name)
 {
 	struct pmu_alias *pmu_alias;
 
@@ -160,7 +160,7 @@ static char *__pmu_find_alias_name(const char *name)
 	return NULL;
 }
 
-char *pmu_find_alias_name(const char *name)
+const char *pmu_find_alias_name(const char *name)
 {
 	if (cached_list)
 		return __pmu_find_alias_name(name);