perf tool: Constify tool pointers

The tool pointer (to a struct largely of function pointers) is passed
around but is unchanged except at initialization. Change parameter and
variable types to be const to lower the possibilities of what could
happen with a tool.

Reviewed-by: Adrian Hunter <adrian.hunter@intel.com>
Signed-off-by: Ian Rogers <irogers@google.com>
Tested-by: Adrian Hunter <adrian.hunter@intel.com>
Tested-by: Leo Yan <leo.yan@arm.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Athira Rajeev <atrajeev@linux.vnet.ibm.com>
Cc: Huacai Chen <chenhuacai@kernel.org>
Cc: Ilkka Koskinen <ilkka@os.amperecomputing.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: James Clark <james.clark@arm.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: John Garry <john.g.garry@oracle.com>
Cc: Jonathan Cameron <jonathan.cameron@huawei.com>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Leo Yan <leo.yan@linux.dev>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mike Leach <mike.leach@linaro.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Nick Desaulniers <ndesaulniers@google.com>
Cc: Nick Terrell <terrelln@fb.com>
Cc: Oliver Upton <oliver.upton@linux.dev>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Song Liu <song@kernel.org>
Cc: Sun Haiyong <sunhaiyong@loongson.cn>
Cc: Suzuki Poulouse <suzuki.poulose@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Yanteng Si <siyanteng@loongson.cn>
Cc: Yicong Yang <yangyicong@hisilicon.com>
Cc: linux-arm-kernel@lists.infradead.org
Link: https://lore.kernel.org/r/20240812204720.631678-4-irogers@google.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

24 files changed, 181 insertions, 181 deletions

diff --git a/tools/perf/util/arm-spe.c b/tools/perf/util/arm-spe.c
index fa40f3cb6266..138ffc71b32d 100644
--- a/tools/perf/util/arm-spe.c
+++ b/tools/perf/util/arm-spe.c
@@ -899,7 +899,7 @@ static int arm_spe_context_switch(struct arm_spe *spe, union perf_event *event,
 static int arm_spe_process_event(struct perf_session *session,
 				 union perf_event *event,
 				 struct perf_sample *sample,
-				 struct perf_tool *tool)
+				 const struct perf_tool *tool)
 {
 	int err = 0;
 	u64 timestamp;
@@ -947,7 +947,7 @@ static int arm_spe_process_event(struct perf_session *session,
 
 static int arm_spe_process_auxtrace_event(struct perf_session *session,
 					  union perf_event *event,
-					  struct perf_tool *tool __maybe_unused)
+					  const struct perf_tool *tool __maybe_unused)
 {
 	struct arm_spe *spe = container_of(session->auxtrace, struct arm_spe,
 					     auxtrace);
@@ -985,7 +985,7 @@ static int arm_spe_process_auxtrace_event(struct perf_session *session,
 }
 
 static int arm_spe_flush(struct perf_session *session __maybe_unused,
-			 struct perf_tool *tool __maybe_unused)
+			 const struct perf_tool *tool __maybe_unused)
 {
 	struct arm_spe *spe = container_of(session->auxtrace, struct arm_spe,
 			auxtrace);
diff --git a/tools/perf/util/auxtrace.c b/tools/perf/util/auxtrace.c
index e2f317063eec..cbb773ed6f1a 100644
--- a/tools/perf/util/auxtrace.c
+++ b/tools/perf/util/auxtrace.c
@@ -1240,7 +1240,7 @@ void auxtrace_synth_error(struct perf_record_auxtrace_error *auxtrace_error, int
 }
 
 int perf_event__synthesize_auxtrace_info(struct auxtrace_record *itr,
-					 struct perf_tool *tool,
+					 const struct perf_tool *tool,
 					 struct perf_session *session,
 					 perf_event__handler_t process)
 {
@@ -1831,7 +1831,7 @@ int __weak compat_auxtrace_mmap__write_tail(struct auxtrace_mmap *mm, u64 tail)
 
 static int __auxtrace_mmap__read(struct mmap *map,
 				 struct auxtrace_record *itr,
-				 struct perf_tool *tool, process_auxtrace_t fn,
+				 const struct perf_tool *tool, process_auxtrace_t fn,
 				 bool snapshot, size_t snapshot_size)
 {
 	struct auxtrace_mmap *mm = &map->auxtrace_mmap;
@@ -1942,14 +1942,14 @@ static int __auxtrace_mmap__read(struct mmap *map,
 }
 
 int auxtrace_mmap__read(struct mmap *map, struct auxtrace_record *itr,
-			struct perf_tool *tool, process_auxtrace_t fn)
+			const struct perf_tool *tool, process_auxtrace_t fn)
 {
 	return __auxtrace_mmap__read(map, itr, tool, fn, false, 0);
 }
 
 int auxtrace_mmap__read_snapshot(struct mmap *map,
 				 struct auxtrace_record *itr,
-				 struct perf_tool *tool, process_auxtrace_t fn,
+				 const struct perf_tool *tool, process_auxtrace_t fn,
 				 size_t snapshot_size)
 {
 	return __auxtrace_mmap__read(map, itr, tool, fn, true, snapshot_size);
@@ -2829,7 +2829,7 @@ int auxtrace_parse_filters(struct evlist *evlist)
 }
 
 int auxtrace__process_event(struct perf_session *session, union perf_event *event,
-			    struct perf_sample *sample, struct perf_tool *tool)
+			    struct perf_sample *sample, const struct perf_tool *tool)
 {
 	if (!session->auxtrace)
 		return 0;
@@ -2847,7 +2847,7 @@ void auxtrace__dump_auxtrace_sample(struct perf_session *session,
 	session->auxtrace->dump_auxtrace_sample(session, sample);
 }
 
-int auxtrace__flush_events(struct perf_session *session, struct perf_tool *tool)
+int auxtrace__flush_events(struct perf_session *session, const struct perf_tool *tool)
 {
 	if (!session->auxtrace)
 		return 0;
diff --git a/tools/perf/util/auxtrace.h b/tools/perf/util/auxtrace.h
index 8a6ec9565835..d405efcd8708 100644
--- a/tools/perf/util/auxtrace.h
+++ b/tools/perf/util/auxtrace.h
@@ -208,17 +208,17 @@ struct auxtrace {
 	int (*process_event)(struct perf_session *session,
 			     union perf_event *event,
 			     struct perf_sample *sample,
-			     struct perf_tool *tool);
+			     const struct perf_tool *tool);
 	int (*process_auxtrace_event)(struct perf_session *session,
 				      union perf_event *event,
-				      struct perf_tool *tool);
+				      const struct perf_tool *tool);
 	int (*queue_data)(struct perf_session *session,
 			  struct perf_sample *sample, union perf_event *event,
 			  u64 data_offset);
 	void (*dump_auxtrace_sample)(struct perf_session *session,
 				     struct perf_sample *sample);
 	int (*flush_events)(struct perf_session *session,
-			    struct perf_tool *tool);
+			    const struct perf_tool *tool);
 	void (*free_events)(struct perf_session *session);
 	void (*free)(struct perf_session *session);
 	bool (*evsel_is_auxtrace)(struct perf_session *session,
@@ -508,17 +508,17 @@ void auxtrace_mmap_params__set_idx(struct auxtrace_mmap_params *mp,
 				   struct evlist *evlist,
 				   struct evsel *evsel, int idx);
 
-typedef int (*process_auxtrace_t)(struct perf_tool *tool,
+typedef int (*process_auxtrace_t)(const struct perf_tool *tool,
 				  struct mmap *map,
 				  union perf_event *event, void *data1,
 				  size_t len1, void *data2, size_t len2);
 
 int auxtrace_mmap__read(struct mmap *map, struct auxtrace_record *itr,
-			struct perf_tool *tool, process_auxtrace_t fn);
+			const struct perf_tool *tool, process_auxtrace_t fn);
 
 int auxtrace_mmap__read_snapshot(struct mmap *map,
 				 struct auxtrace_record *itr,
-				 struct perf_tool *tool, process_auxtrace_t fn,
+				 const struct perf_tool *tool, process_auxtrace_t fn,
 				 size_t snapshot_size);
 
 int auxtrace_queues__init_nr(struct auxtrace_queues *queues, int nr_queues);
@@ -639,10 +639,10 @@ int addr_filters__parse_bare_filter(struct addr_filters *filts,
 int auxtrace_parse_filters(struct evlist *evlist);
 
 int auxtrace__process_event(struct perf_session *session, union perf_event *event,
-			    struct perf_sample *sample, struct perf_tool *tool);
+			    struct perf_sample *sample, const struct perf_tool *tool);
 void auxtrace__dump_auxtrace_sample(struct perf_session *session,
 				    struct perf_sample *sample);
-int auxtrace__flush_events(struct perf_session *session, struct perf_tool *tool);
+int auxtrace__flush_events(struct perf_session *session, const struct perf_tool *tool);
 void auxtrace__free_events(struct perf_session *session);
 void auxtrace__free(struct perf_session *session);
 bool auxtrace__evsel_is_auxtrace(struct perf_session *session,
@@ -809,7 +809,7 @@ static inline
 int auxtrace__process_event(struct perf_session *session __maybe_unused,
 			    union perf_event *event __maybe_unused,
 			    struct perf_sample *sample __maybe_unused,
-			    struct perf_tool *tool __maybe_unused)
+			    const struct perf_tool *tool __maybe_unused)
 {
 	return 0;
 }
@@ -822,7 +822,7 @@ void auxtrace__dump_auxtrace_sample(struct perf_session *session __maybe_unused,
 
 static inline
 int auxtrace__flush_events(struct perf_session *session __maybe_unused,
-			   struct perf_tool *tool __maybe_unused)
+			   const struct perf_tool *tool __maybe_unused)
 {
 	return 0;
 }
diff --git a/tools/perf/util/bpf-event.c b/tools/perf/util/bpf-event.c
index 827695cd0408..13608237c50e 100644
--- a/tools/perf/util/bpf-event.c
+++ b/tools/perf/util/bpf-event.c
@@ -170,7 +170,7 @@ static int perf_event__synthesize_one_bpf_prog(struct perf_session *session,
 {
 	struct perf_record_ksymbol *ksymbol_event = &event->ksymbol;
 	struct perf_record_bpf_event *bpf_event = &event->bpf;
-	struct perf_tool *tool = session->tool;
+	const struct perf_tool *tool = session->tool;
 	struct bpf_prog_info_node *info_node;
 	struct perf_bpil *info_linear;
 	struct bpf_prog_info *info;
@@ -310,7 +310,7 @@ struct kallsyms_parse {
 	union perf_event	*event;
 	perf_event__handler_t	 process;
 	struct machine		*machine;
-	struct perf_tool	*tool;
+	const struct perf_tool	*tool;
 };
 
 static int
diff --git a/tools/perf/util/build-id.c b/tools/perf/util/build-id.c
index 83a1581e8cf1..098fcc625d91 100644
--- a/tools/perf/util/build-id.c
+++ b/tools/perf/util/build-id.c
@@ -42,7 +42,7 @@
 
 static bool no_buildid_cache;
 
-int build_id__mark_dso_hit(struct perf_tool *tool __maybe_unused,
+int build_id__mark_dso_hit(const struct perf_tool *tool __maybe_unused,
 			   union perf_event *event,
 			   struct perf_sample *sample,
 			   struct evsel *evsel __maybe_unused,
@@ -67,7 +67,7 @@ int build_id__mark_dso_hit(struct perf_tool *tool __maybe_unused,
 	return 0;
 }
 
-static int perf_event__exit_del_thread(struct perf_tool *tool __maybe_unused,
+static int perf_event__exit_del_thread(const struct perf_tool *tool __maybe_unused,
 				       union perf_event *event,
 				       struct perf_sample *sample
 				       __maybe_unused,
diff --git a/tools/perf/util/build-id.h b/tools/perf/util/build-id.h
index 3fa8bffb07ca..ae87c4c58d5b 100644
--- a/tools/perf/util/build-id.h
+++ b/tools/perf/util/build-id.h
@@ -35,11 +35,11 @@ char *dso__build_id_filename(const struct dso *dso, char *bf, size_t size,
 char *__dso__build_id_filename(const struct dso *dso, char *bf, size_t size,
 			       bool is_debug, bool is_kallsyms);
 
-int build_id__mark_dso_hit(struct perf_tool *tool, union perf_event *event,
+int build_id__mark_dso_hit(const struct perf_tool *tool, union perf_event *event,
 			   struct perf_sample *sample, struct evsel *evsel,
 			   struct machine *machine);
 
-int perf_event__inject_buildid(struct perf_tool *tool, union perf_event *event,
+int perf_event__inject_buildid(const struct perf_tool *tool, union perf_event *event,
 			       struct perf_sample *sample, struct evsel *evsel,
 			       struct machine *machine);
 
diff --git a/tools/perf/util/cs-etm.c b/tools/perf/util/cs-etm.c
index 566498ebc694..34552940ec1d 100644
--- a/tools/perf/util/cs-etm.c
+++ b/tools/perf/util/cs-etm.c
@@ -788,7 +788,7 @@ static void cs_etm__dump_event(struct cs_etm_queue *etmq,
 }
 
 static int cs_etm__flush_events(struct perf_session *session,
-				struct perf_tool *tool)
+				const struct perf_tool *tool)
 {
 	struct cs_etm_auxtrace *etm = container_of(session->auxtrace,
 						   struct cs_etm_auxtrace,
@@ -2715,7 +2715,7 @@ static int cs_etm__process_switch_cpu_wide(struct cs_etm_auxtrace *etm,
 static int cs_etm__process_event(struct perf_session *session,
 				 union perf_event *event,
 				 struct perf_sample *sample,
-				 struct perf_tool *tool)
+				 const struct perf_tool *tool)
 {
 	struct cs_etm_auxtrace *etm = container_of(session->auxtrace,
 						   struct cs_etm_auxtrace,
@@ -2785,7 +2785,7 @@ static void dump_queued_data(struct cs_etm_auxtrace *etm,
 
 static int cs_etm__process_auxtrace_event(struct perf_session *session,
 					  union perf_event *event,
-					  struct perf_tool *tool __maybe_unused)
+					  const struct perf_tool *tool __maybe_unused)
 {
 	struct cs_etm_auxtrace *etm = container_of(session->auxtrace,
 						   struct cs_etm_auxtrace,
diff --git a/tools/perf/util/data-convert-bt.c b/tools/perf/util/data-convert-bt.c
index 2b732bccabad..9e2170604b66 100644
--- a/tools/perf/util/data-convert-bt.c
+++ b/tools/perf/util/data-convert-bt.c
@@ -792,7 +792,7 @@ static bool is_flush_needed(struct ctf_stream *cs)
 	return cs->count >= STREAM_FLUSH_COUNT;
 }
 
-static int process_sample_event(struct perf_tool *tool,
+static int process_sample_event(const struct perf_tool *tool,
 				union perf_event *_event,
 				struct perf_sample *sample,
 				struct evsel *evsel,
@@ -871,7 +871,7 @@ do {							\
 } while(0)
 
 #define __FUNC_PROCESS_NON_SAMPLE(_name, body) 	\
-static int process_##_name##_event(struct perf_tool *tool,	\
+static int process_##_name##_event(const struct perf_tool *tool,	\
 				   union perf_event *_event,	\
 				   struct perf_sample *sample,	\
 				   struct machine *machine)	\
diff --git a/tools/perf/util/data-convert-json.c b/tools/perf/util/data-convert-json.c
index 3cf64f5b23ee..905ea9823f9d 100644
--- a/tools/perf/util/data-convert-json.c
+++ b/tools/perf/util/data-convert-json.c
@@ -118,7 +118,7 @@ static void output_json_key_format(FILE *out, bool comma, int depth,
 	va_end(args);
 }
 
-static void output_sample_callchain_entry(struct perf_tool *tool,
+static void output_sample_callchain_entry(const struct perf_tool *tool,
 		u64 ip, struct addr_location *al)
 {
 	struct convert_json *c = container_of(tool, struct convert_json, tool);
@@ -146,7 +146,7 @@ static void output_sample_callchain_entry(struct perf_tool *tool,
 	output_json_format(out, false, 4, "}");
 }
 
-static int process_sample_event(struct perf_tool *tool,
+static int process_sample_event(const struct perf_tool *tool,
 				union perf_event *event __maybe_unused,
 				struct perf_sample *sample,
 				struct evsel *evsel __maybe_unused,
diff --git a/tools/perf/util/event.c b/tools/perf/util/event.c
index f32f9abf6344..c2f0e7f40ad5 100644
--- a/tools/perf/util/event.c
+++ b/tools/perf/util/event.c
@@ -216,7 +216,7 @@ size_t perf_event__fprintf_cgroup(union perf_event *event, FILE *fp)
 		       event->cgroup.id, event->cgroup.path);
 }
 
-int perf_event__process_comm(struct perf_tool *tool __maybe_unused,
+int perf_event__process_comm(const struct perf_tool *tool __maybe_unused,
 			     union perf_event *event,
 			     struct perf_sample *sample,
 			     struct machine *machine)
@@ -224,7 +224,7 @@ int perf_event__process_comm(struct perf_tool *tool __maybe_unused,
 	return machine__process_comm_event(machine, event, sample);
 }
 
-int perf_event__process_namespaces(struct perf_tool *tool __maybe_unused,
+int perf_event__process_namespaces(const struct perf_tool *tool __maybe_unused,
 				   union perf_event *event,
 				   struct perf_sample *sample,
 				   struct machine *machine)
@@ -232,7 +232,7 @@ int perf_event__process_namespaces(struct perf_tool *tool __maybe_unused,
 	return machine__process_namespaces_event(machine, event, sample);
 }
 
-int perf_event__process_cgroup(struct perf_tool *tool __maybe_unused,
+int perf_event__process_cgroup(const struct perf_tool *tool __maybe_unused,
 			       union perf_event *event,
 			       struct perf_sample *sample,
 			       struct machine *machine)
@@ -240,7 +240,7 @@ int perf_event__process_cgroup(struct perf_tool *tool __maybe_unused,
 	return machine__process_cgroup_event(machine, event, sample);
 }
 
-int perf_event__process_lost(struct perf_tool *tool __maybe_unused,
+int perf_event__process_lost(const struct perf_tool *tool __maybe_unused,
 			     union perf_event *event,
 			     struct perf_sample *sample,
 			     struct machine *machine)
@@ -248,7 +248,7 @@ int perf_event__process_lost(struct perf_tool *tool __maybe_unused,
 	return machine__process_lost_event(machine, event, sample);
 }
 
-int perf_event__process_aux(struct perf_tool *tool __maybe_unused,
+int perf_event__process_aux(const struct perf_tool *tool __maybe_unused,
 			    union perf_event *event,
 			    struct perf_sample *sample __maybe_unused,
 			    struct machine *machine)
@@ -256,7 +256,7 @@ int perf_event__process_aux(struct perf_tool *tool __maybe_unused,
 	return machine__process_aux_event(machine, event);
 }
 
-int perf_event__process_itrace_start(struct perf_tool *tool __maybe_unused,
+int perf_event__process_itrace_start(const struct perf_tool *tool __maybe_unused,
 				     union perf_event *event,
 				     struct perf_sample *sample __maybe_unused,
 				     struct machine *machine)
@@ -264,7 +264,7 @@ int perf_event__process_itrace_start(struct perf_tool *tool __maybe_unused,
 	return machine__process_itrace_start_event(machine, event);
 }
 
-int perf_event__process_aux_output_hw_id(struct perf_tool *tool __maybe_unused,
+int perf_event__process_aux_output_hw_id(const struct perf_tool *tool __maybe_unused,
 					 union perf_event *event,
 					 struct perf_sample *sample __maybe_unused,
 					 struct machine *machine)
@@ -272,7 +272,7 @@ int perf_event__process_aux_output_hw_id(struct perf_tool *tool __maybe_unused,
 	return machine__process_aux_output_hw_id_event(machine, event);
 }
 
-int perf_event__process_lost_samples(struct perf_tool *tool __maybe_unused,
+int perf_event__process_lost_samples(const struct perf_tool *tool __maybe_unused,
 				     union perf_event *event,
 				     struct perf_sample *sample,
 				     struct machine *machine)
@@ -280,7 +280,7 @@ int perf_event__process_lost_samples(struct perf_tool *tool __maybe_unused,
 	return machine__process_lost_samples_event(machine, event, sample);
 }
 
-int perf_event__process_switch(struct perf_tool *tool __maybe_unused,
+int perf_event__process_switch(const struct perf_tool *tool __maybe_unused,
 			       union perf_event *event,
 			       struct perf_sample *sample __maybe_unused,
 			       struct machine *machine)
@@ -288,7 +288,7 @@ int perf_event__process_switch(struct perf_tool *tool __maybe_unused,
 	return machine__process_switch_event(machine, event);
 }
 
-int perf_event__process_ksymbol(struct perf_tool *tool __maybe_unused,
+int perf_event__process_ksymbol(const struct perf_tool *tool __maybe_unused,
 				union perf_event *event,
 				struct perf_sample *sample __maybe_unused,
 				struct machine *machine)
@@ -296,7 +296,7 @@ int perf_event__process_ksymbol(struct perf_tool *tool __maybe_unused,
 	return machine__process_ksymbol(machine, event, sample);
 }
 
-int perf_event__process_bpf(struct perf_tool *tool __maybe_unused,
+int perf_event__process_bpf(const struct perf_tool *tool __maybe_unused,
 			    union perf_event *event,
 			    struct perf_sample *sample,
 			    struct machine *machine)
@@ -304,7 +304,7 @@ int perf_event__process_bpf(struct perf_tool *tool __maybe_unused,
 	return machine__process_bpf(machine, event, sample);
 }
 
-int perf_event__process_text_poke(struct perf_tool *tool __maybe_unused,
+int perf_event__process_text_poke(const struct perf_tool *tool __maybe_unused,
 				  union perf_event *event,
 				  struct perf_sample *sample,
 				  struct machine *machine)
@@ -387,7 +387,7 @@ size_t perf_event__fprintf_cpu_map(union perf_event *event, FILE *fp)
 	return ret;
 }
 
-int perf_event__process_mmap(struct perf_tool *tool __maybe_unused,
+int perf_event__process_mmap(const struct perf_tool *tool __maybe_unused,
 			     union perf_event *event,
 			     struct perf_sample *sample,
 			     struct machine *machine)
@@ -395,7 +395,7 @@ int perf_event__process_mmap(struct perf_tool *tool __maybe_unused,
 	return machine__process_mmap_event(machine, event, sample);
 }
 
-int perf_event__process_mmap2(struct perf_tool *tool __maybe_unused,
+int perf_event__process_mmap2(const struct perf_tool *tool __maybe_unused,
 			     union perf_event *event,
 			     struct perf_sample *sample,
 			     struct machine *machine)
@@ -410,7 +410,7 @@ size_t perf_event__fprintf_task(union perf_event *event, FILE *fp)
 		       event->fork.ppid, event->fork.ptid);
 }
 
-int perf_event__process_fork(struct perf_tool *tool __maybe_unused,
+int perf_event__process_fork(const struct perf_tool *tool __maybe_unused,
 			     union perf_event *event,
 			     struct perf_sample *sample,
 			     struct machine *machine)
@@ -418,7 +418,7 @@ int perf_event__process_fork(struct perf_tool *tool __maybe_unused,
 	return machine__process_fork_event(machine, event, sample);
 }
 
-int perf_event__process_exit(struct perf_tool *tool __maybe_unused,
+int perf_event__process_exit(const struct perf_tool *tool __maybe_unused,
 			     union perf_event *event,
 			     struct perf_sample *sample,
 			     struct machine *machine)
@@ -587,7 +587,7 @@ size_t perf_event__fprintf(union perf_event *event, struct machine *machine, FIL
 	return ret;
 }
 
-int perf_event__process(struct perf_tool *tool __maybe_unused,
+int perf_event__process(const struct perf_tool *tool __maybe_unused,
 			union perf_event *event,
 			struct perf_sample *sample,
 			struct machine *machine)
diff --git a/tools/perf/util/event.h b/tools/perf/util/event.h
index d8bcee2e9b93..4b24f1c580fd 100644
--- a/tools/perf/util/event.h
+++ b/tools/perf/util/event.h
@@ -267,71 +267,71 @@ struct perf_tool;
 void perf_event__read_stat_config(struct perf_stat_config *config,
 				  struct perf_record_stat_config *event);
 
-int perf_event__process_comm(struct perf_tool *tool,
+int perf_event__process_comm(const struct perf_tool *tool,
 			     union perf_event *event,
 			     struct perf_sample *sample,
 			     struct machine *machine);
-int perf_event__process_lost(struct perf_tool *tool,
+int perf_event__process_lost(const struct perf_tool *tool,
 			     union perf_event *event,
 			     struct perf_sample *sample,
 			     struct machine *machine);
-int perf_event__process_lost_samples(struct perf_tool *tool,
+int perf_event__process_lost_samples(const struct perf_tool *tool,
 				     union perf_event *event,
 				     struct perf_sample *sample,
 				     struct machine *machine);
-int perf_event__process_aux(struct perf_tool *tool,
+int perf_event__process_aux(const struct perf_tool *tool,
 			    union perf_event *event,
 			    struct perf_sample *sample,
 			    struct machine *machine);
-int perf_event__process_itrace_start(struct perf_tool *tool,
+int perf_event__process_itrace_start(const struct perf_tool *tool,
 				     union perf_event *event,
 				     struct perf_sample *sample,
 				     struct machine *machine);
-int perf_event__process_aux_output_hw_id(struct perf_tool *tool,
+int perf_event__process_aux_output_hw_id(const struct perf_tool *tool,
 					 union perf_event *event,
 					 struct perf_sample *sample,
 					 struct machine *machine);
-int perf_event__process_switch(struct perf_tool *tool,
+int perf_event__process_switch(const struct perf_tool *tool,
 			       union perf_event *event,
 			       struct perf_sample *sample,
 			       struct machine *machine);
-int perf_event__process_namespaces(struct perf_tool *tool,
+int perf_event__process_namespaces(const struct perf_tool *tool,
 				   union perf_event *event,
 				   struct perf_sample *sample,
 				   struct machine *machine);
-int perf_event__process_cgroup(struct perf_tool *tool,
+int perf_event__process_cgroup(const struct perf_tool *tool,
 			       union perf_event *event,
 			       struct perf_sample *sample,
 			       struct machine *machine);
-int perf_event__process_mmap(struct perf_tool *tool,
+int perf_event__process_mmap(const struct perf_tool *tool,
 			     union perf_event *event,
 			     struct perf_sample *sample,
 			     struct machine *machine);
-int perf_event__process_mmap2(struct perf_tool *tool,
+int perf_event__process_mmap2(const struct perf_tool *tool,
 			     union perf_event *event,
 			     struct perf_sample *sample,
 			     struct machine *machine);
-int perf_event__process_fork(struct perf_tool *tool,
+int perf_event__process_fork(const struct perf_tool *tool,
 			     union perf_event *event,
 			     struct perf_sample *sample,
 			     struct machine *machine);
-int perf_event__process_exit(struct perf_tool *tool,
+int perf_event__process_exit(const struct perf_tool *tool,
 			     union perf_event *event,
 			     struct perf_sample *sample,
 			     struct machine *machine);
-int perf_event__process_ksymbol(struct perf_tool *tool,
+int perf_event__process_ksymbol(const struct perf_tool *tool,
 				union perf_event *event,
 				struct perf_sample *sample,
 				struct machine *machine);
-int perf_event__process_bpf(struct perf_tool *tool,
+int perf_event__process_bpf(const struct perf_tool *tool,
 			    union perf_event *event,
 			    struct perf_sample *sample,
 			    struct machine *machine);
-int perf_event__process_text_poke(struct perf_tool *tool,
+int perf_event__process_text_poke(const struct perf_tool *tool,
 				  union perf_event *event,
 				  struct perf_sample *sample,
 				  struct machine *machine);
-int perf_event__process(struct perf_tool *tool,
+int perf_event__process(const struct perf_tool *tool,
 			union perf_event *event,
 			struct perf_sample *sample,
 			struct machine *machine);
diff --git a/tools/perf/util/header.c b/tools/perf/util/header.c
index 55e9553861d0..3309fe7f1d12 100644
--- a/tools/perf/util/header.c
+++ b/tools/perf/util/header.c
@@ -4326,7 +4326,7 @@ out_delete_evlist:
 int perf_event__process_feature(struct perf_session *session,
 				union perf_event *event)
 {
-	struct perf_tool *tool = session->tool;
+	const struct perf_tool *tool = session->tool;
 	struct feat_fd ff = { .fd = 0 };
 	struct perf_record_header_feature *fe = (struct perf_record_header_feature *)event;
 	int type = fe->header.type;
@@ -4405,7 +4405,7 @@ size_t perf_event__fprintf_event_update(union perf_event *event, FILE *fp)
 	return ret;
 }
 
-int perf_event__process_attr(struct perf_tool *tool __maybe_unused,
+int perf_event__process_attr(const struct perf_tool *tool __maybe_unused,
 			     union perf_event *event,
 			     struct evlist **pevlist)
 {
@@ -4444,7 +4444,7 @@ int perf_event__process_attr(struct perf_tool *tool __maybe_unused,
 	return 0;
 }
 
-int perf_event__process_event_update(struct perf_tool *tool __maybe_unused,
+int perf_event__process_event_update(const struct perf_tool *tool __maybe_unused,
 				     union perf_event *event,
 				     struct evlist **pevlist)
 {
diff --git a/tools/perf/util/header.h b/tools/perf/util/header.h
index 7c16a250e738..07ff647197ff 100644
--- a/tools/perf/util/header.h
+++ b/tools/perf/util/header.h
@@ -156,9 +156,9 @@ int perf_header__fprintf_info(struct perf_session *s, FILE *fp, bool full);
 
 int perf_event__process_feature(struct perf_session *session,
 				union perf_event *event);
-int perf_event__process_attr(struct perf_tool *tool, union perf_event *event,
+int perf_event__process_attr(const struct perf_tool *tool, union perf_event *event,
 			     struct evlist **pevlist);
-int perf_event__process_event_update(struct perf_tool *tool,
+int perf_event__process_event_update(const struct perf_tool *tool,
 				     union perf_event *event,
 				     struct evlist **pevlist);
 size_t perf_event__fprintf_event_update(union perf_event *event, FILE *fp);
diff --git a/tools/perf/util/hisi-ptt.c b/tools/perf/util/hisi-ptt.c
index 37ea987017f6..e4cc4785f744 100644
--- a/tools/perf/util/hisi-ptt.c
+++ b/tools/perf/util/hisi-ptt.c
@@ -79,14 +79,14 @@ static void hisi_ptt_dump_event(struct hisi_ptt *ptt, unsigned char *buf,
 static int hisi_ptt_process_event(struct perf_session *session __maybe_unused,
 				  union perf_event *event __maybe_unused,
 				  struct perf_sample *sample __maybe_unused,
-				  struct perf_tool *tool __maybe_unused)
+				  const struct perf_tool *tool __maybe_unused)
 {
 	return 0;
 }
 
 static int hisi_ptt_process_auxtrace_event(struct perf_session *session,
 					   union perf_event *event,
-					   struct perf_tool *tool __maybe_unused)
+					   const struct perf_tool *tool __maybe_unused)
 {
 	struct hisi_ptt *ptt = container_of(session->auxtrace, struct hisi_ptt,
 					    auxtrace);
@@ -123,7 +123,7 @@ static int hisi_ptt_process_auxtrace_event(struct perf_session *session,
 }
 
 static int hisi_ptt_flush(struct perf_session *session __maybe_unused,
-			  struct perf_tool *tool __maybe_unused)
+			  const struct perf_tool *tool __maybe_unused)
 {
 	return 0;
 }
diff --git a/tools/perf/util/intel-bts.c b/tools/perf/util/intel-bts.c
index 160d346cb450..27d9b5c9fec8 100644
--- a/tools/perf/util/intel-bts.c
+++ b/tools/perf/util/intel-bts.c
@@ -591,7 +591,7 @@ static int intel_bts_process_queues(struct intel_bts *bts, u64 timestamp)
 static int intel_bts_process_event(struct perf_session *session,
 				   union perf_event *event,
 				   struct perf_sample *sample,
-				   struct perf_tool *tool)
+				   const struct perf_tool *tool)
 {
 	struct intel_bts *bts = container_of(session->auxtrace, struct intel_bts,
 					     auxtrace);
@@ -634,7 +634,7 @@ static int intel_bts_process_event(struct perf_session *session,
 
 static int intel_bts_process_auxtrace_event(struct perf_session *session,
 					    union perf_event *event,
-					    struct perf_tool *tool __maybe_unused)
+					    const struct perf_tool *tool __maybe_unused)
 {
 	struct intel_bts *bts = container_of(session->auxtrace, struct intel_bts,
 					     auxtrace);
@@ -675,7 +675,7 @@ static int intel_bts_process_auxtrace_event(struct perf_session *session,
 }
 
 static int intel_bts_flush(struct perf_session *session,
-			   struct perf_tool *tool __maybe_unused)
+			   const struct perf_tool *tool __maybe_unused)
 {
 	struct intel_bts *bts = container_of(session->auxtrace, struct intel_bts,
 					     auxtrace);
diff --git a/tools/perf/util/intel-pt.c b/tools/perf/util/intel-pt.c
index 1fc03bfd14c3..fd2597613f3d 100644
--- a/tools/perf/util/intel-pt.c
+++ b/tools/perf/util/intel-pt.c
@@ -3449,7 +3449,7 @@ out:
 static int intel_pt_process_event(struct perf_session *session,
 				  union perf_event *event,
 				  struct perf_sample *sample,
-				  struct perf_tool *tool)
+				  const struct perf_tool *tool)
 {
 	struct intel_pt *pt = container_of(session->auxtrace, struct intel_pt,
 					   auxtrace);
@@ -3533,7 +3533,7 @@ static int intel_pt_process_event(struct perf_session *session,