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 <[e-mail]>
Signed-off-by: Ian Rogers <[e-mail]>
Tested-by: Adrian Hunter <[e-mail]>
Tested-by: Leo Yan <[e-mail]>
Cc: Alexander Shishkin <[e-mail]>
Cc: Anshuman Khandual <[e-mail]>
Cc: Athira Rajeev <[e-mail]>
Cc: Huacai Chen <[e-mail]>
Cc: Ilkka Koskinen <[e-mail]>
Cc: Ingo Molnar <[e-mail]>
Cc: James Clark <[e-mail]>
Cc: Jiri Olsa <[e-mail]>
Cc: John Garry <[e-mail]>
Cc: Jonathan Cameron <[e-mail]>
Cc: Kan Liang <[e-mail]>
Cc: Leo Yan <[e-mail]>
Cc: Mark Rutland <[e-mail]>
Cc: Mike Leach <[e-mail]>
Cc: Namhyung Kim <[e-mail]>
Cc: Nick Desaulniers <[e-mail]>
Cc: Nick Terrell <[e-mail]>
Cc: Oliver Upton <[e-mail]>
Cc: Peter Zijlstra <[e-mail]>
Cc: Song Liu <[e-mail]>
Cc: Sun Haiyong <[e-mail]>
Cc: Suzuki Poulouse <[e-mail]>
Cc: Will Deacon <[e-mail]>
Cc: Yanteng Si <[e-mail]>
Cc: Yicong Yang <[e-mail]>
Cc: [e-mail]
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Arnaldo Carvalho de Melo <[e-mail]>

tools/perf/arch/x86/util/event.c

···
 #if defined(__x86_64__)
 
 struct perf_event__synthesize_extra_kmaps_cb_args {
-	struct perf_tool *tool;
+	const struct perf_tool *tool;
 	perf_event__handler_t process;
 	struct machine *machine;
 	union perf_event *event;
···
 	return 0;
 }
 
-int perf_event__synthesize_extra_kmaps(struct perf_tool *tool,
+int perf_event__synthesize_extra_kmaps(const struct perf_tool *tool,
 				       perf_event__handler_t process,
 				       struct machine *machine)
 {

tools/perf/bench/synthesize.c

···
 
 static atomic_t event_count;
 
-static int process_synthesized_event(struct perf_tool *tool __maybe_unused,
+static int process_synthesized_event(const struct perf_tool *tool __maybe_unused,
 				     union perf_event *event __maybe_unused,
 				     struct perf_sample *sample __maybe_unused,
 				     struct machine *machine __maybe_unused)

tools/perf/builtin-annotate.c

···
 	return ret;
 }
 
-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,

tools/perf/builtin-c2c.c

···
 		update_stats(&cstats->load, weight);
 }
 
-static int process_sample_event(struct perf_tool *tool __maybe_unused,
+static int process_sample_event(const struct perf_tool *tool __maybe_unused,
 				union perf_event *event,
 				struct perf_sample *sample,
 				struct evsel *evsel,

tools/perf/builtin-diff.c

···
 	.free   = block_hist_free,
 };
 
-static int diff__process_sample_event(struct perf_tool *tool,
+static int diff__process_sample_event(const struct perf_tool *tool,
 				      union perf_event *event,
 				      struct perf_sample *sample,
 				      struct evsel *evsel,

tools/perf/builtin-inject.c

···
 	union perf_event event[];
 };
 
-static int dso__inject_build_id(struct dso *dso, struct perf_tool *tool,
+static int dso__inject_build_id(struct dso *dso, const struct perf_tool *tool,
 				struct machine *machine, u8 cpumode, u32 flags);
 
 static int output_bytes(struct perf_inject *inject, void *buf, size_t sz)
···
 	return 0;
 }
 
-static int perf_event__repipe_synth(struct perf_tool *tool,
+static int perf_event__repipe_synth(const struct perf_tool *tool,
 				    union perf_event *event)
 {
 	struct perf_inject *inject = container_of(tool, struct perf_inject,
···
 	return output_bytes(inject, event, event->header.size);
 }
 
-static int perf_event__repipe_oe_synth(struct perf_tool *tool,
+static int perf_event__repipe_oe_synth(const struct perf_tool *tool,
 				       union perf_event *event,
 				       struct ordered_events *oe __maybe_unused)
 {
···
 }
 
 #ifdef HAVE_JITDUMP
-static int perf_event__drop_oe(struct perf_tool *tool __maybe_unused,
+static int perf_event__drop_oe(const struct perf_tool *tool __maybe_unused,
 			       union perf_event *event __maybe_unused,
 			       struct ordered_events *oe __maybe_unused)
 {
···
 	return perf_event__repipe_synth(session->tool, event);
 }
 
-static int perf_event__repipe_attr(struct perf_tool *tool,
+static int perf_event__repipe_attr(const struct perf_tool *tool,
 				   union perf_event *event,
 				   struct evlist **pevlist)
 {
···
 	return perf_event__repipe_synth(tool, event);
 }
 
-static int perf_event__repipe_event_update(struct perf_tool *tool,
+static int perf_event__repipe_event_update(const struct perf_tool *tool,
 					   union perf_event *event,
 					   struct evlist **pevlist __maybe_unused)
 {
···
 static s64 perf_event__repipe_auxtrace(struct perf_session *session,
 				       union perf_event *event)
 {
-	struct perf_tool *tool = session->tool;
+	const struct perf_tool *tool = session->tool;
 	struct perf_inject *inject = container_of(tool, struct perf_inject,
 						  tool);
 	int ret;
···
 
 #endif
 
-static int perf_event__repipe(struct perf_tool *tool,
+static int perf_event__repipe(const struct perf_tool *tool,
 			      union perf_event *event,
 			      struct perf_sample *sample __maybe_unused,
 			      struct machine *machine __maybe_unused)
···
 	return perf_event__repipe_synth(tool, event);
 }
 
-static int perf_event__drop(struct perf_tool *tool __maybe_unused,
+static int perf_event__drop(const struct perf_tool *tool __maybe_unused,
 			    union perf_event *event __maybe_unused,
 			    struct perf_sample *sample __maybe_unused,
 			    struct machine *machine __maybe_unused)
···
 	return 0;
 }
 
-static int perf_event__drop_aux(struct perf_tool *tool,
+static int perf_event__drop_aux(const struct perf_tool *tool,
 				union perf_event *event __maybe_unused,
 				struct perf_sample *sample,
 				struct machine *machine __maybe_unused)
···
 	return ev;
 }
 
-typedef int (*inject_handler)(struct perf_tool *tool,
+typedef int (*inject_handler)(const struct perf_tool *tool,
 			      union perf_event *event,
 			      struct perf_sample *sample,
 			      struct evsel *evsel,
 			      struct machine *machine);
 
-static int perf_event__repipe_sample(struct perf_tool *tool,
+static int perf_event__repipe_sample(const struct perf_tool *tool,
 				     union perf_event *event,
 				     struct perf_sample *sample,
 				     struct evsel *evsel,
···
 	return perf_event__repipe_synth(tool, event);
 }
 
-static int perf_event__repipe_mmap(struct perf_tool *tool,
+static int perf_event__repipe_mmap(const struct perf_tool *tool,
 				   union perf_event *event,
 				   struct perf_sample *sample,
 				   struct machine *machine)
···
 }
 
 #ifdef HAVE_JITDUMP
-static int perf_event__jit_repipe_mmap(struct perf_tool *tool,
+static int perf_event__jit_repipe_mmap(const struct perf_tool *tool,
 				       union perf_event *event,
 				       struct perf_sample *sample,
 				       struct machine *machine)
···
 	return dso;
 }
 
-static int perf_event__repipe_buildid_mmap(struct perf_tool *tool,
+static int perf_event__repipe_buildid_mmap(const struct perf_tool *tool,
 					   union perf_event *event,
 					   struct perf_sample *sample,
 					   struct machine *machine)
···
 	return perf_event__repipe(tool, event, sample, machine);
 }
 
-static int perf_event__repipe_mmap2(struct perf_tool *tool,
+static int perf_event__repipe_mmap2(const struct perf_tool *tool,
 				   union perf_event *event,
 				   struct perf_sample *sample,
 				   struct machine *machine)
···
 }
 
 #ifdef HAVE_JITDUMP
-static int perf_event__jit_repipe_mmap2(struct perf_tool *tool,
+static int perf_event__jit_repipe_mmap2(const struct perf_tool *tool,
 					union perf_event *event,
 					struct perf_sample *sample,
 					struct machine *machine)
···
 }
 #endif
 
-static int perf_event__repipe_buildid_mmap2(struct perf_tool *tool,
+static int perf_event__repipe_buildid_mmap2(const struct perf_tool *tool,
 					    union perf_event *event,
 					    struct perf_sample *sample,
 					    struct machine *machine)
···
 	return 0;
 }
 
-static int perf_event__repipe_fork(struct perf_tool *tool,
+static int perf_event__repipe_fork(const struct perf_tool *tool,
 				   union perf_event *event,
 				   struct perf_sample *sample,
 				   struct machine *machine)
···
 	return err;
 }
 
-static int perf_event__repipe_comm(struct perf_tool *tool,
+static int perf_event__repipe_comm(const struct perf_tool *tool,
 				   union perf_event *event,
 				   struct perf_sample *sample,
 				   struct machine *machine)
···
 	return err;
 }
 
-static int perf_event__repipe_namespaces(struct perf_tool *tool,
+static int perf_event__repipe_namespaces(const struct perf_tool *tool,
 					 union perf_event *event,
 					 struct perf_sample *sample,
 					 struct machine *machine)
···
 	return err;
 }
 
-static int perf_event__repipe_exit(struct perf_tool *tool,
+static int perf_event__repipe_exit(const struct perf_tool *tool,
 				   union perf_event *event,
 				   struct perf_sample *sample,
 				   struct machine *machine)
···
 	return false;
 }
 
-static int dso__inject_build_id(struct dso *dso, struct perf_tool *tool,
+static int dso__inject_build_id(struct dso *dso, const struct perf_tool *tool,
 				struct machine *machine, u8 cpumode, u32 flags)
 {
 	struct perf_inject *inject = container_of(tool, struct perf_inject,
···
 	return 0;
 }
 
-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 __maybe_unused,
 			       struct machine *machine)
···
 	return 0;
 }
 
-static int perf_inject__sched_process_exit(struct perf_tool *tool,
+static int perf_inject__sched_process_exit(const struct perf_tool *tool,
 					   union perf_event *event __maybe_unused,
 					   struct perf_sample *sample,
 					   struct evsel *evsel __maybe_unused,
···
 	return 0;
 }
 
-static int perf_inject__sched_switch(struct perf_tool *tool,
+static int perf_inject__sched_switch(const struct perf_tool *tool,
 				     union perf_event *event,
 				     struct perf_sample *sample,
 				     struct evsel *evsel,
···
 }
 
 #ifdef HAVE_LIBTRACEEVENT
-static int perf_inject__sched_stat(struct perf_tool *tool,
+static int perf_inject__sched_stat(const struct perf_tool *tool,
 				   union perf_event *event __maybe_unused,
 				   struct perf_sample *sample,
 				   struct evsel *evsel,
···
 	return ret < 0 ? ret : 0;
 }
 
-static int guest_session__repipe(struct perf_tool *tool,
+static int guest_session__repipe(const struct perf_tool *tool,
 				 union perf_event *event,
 				 struct perf_sample *sample __maybe_unused,
 				 struct machine *machine __maybe_unused)
···
 	return NULL;
 }
 
-static int process_attr(struct perf_tool *tool, union perf_event *event,
+static int process_attr(const struct perf_tool *tool, union perf_event *event,
 			struct perf_sample *sample __maybe_unused,
 			struct machine *machine __maybe_unused)
 {
···
 	return 0;
 }
 
-static int process_build_id(struct perf_tool *tool,
+static int process_build_id(const struct perf_tool *tool,
 			    union perf_event *event,
 			    struct perf_sample *sample __maybe_unused,
 			    struct machine *machine __maybe_unused)
···
 				  gs);
 }
 
-static int guest_session__ksymbol_event(struct perf_tool *tool,
+static int guest_session__ksymbol_event(const struct perf_tool *tool,
 					union perf_event *event,
 					struct perf_sample *sample __maybe_unused,
 					struct machine *machine __maybe_unused)
···
 	return guest_session__inject_events(gs, -1);
 }
 
-static int host__repipe(struct perf_tool *tool,
+static int host__repipe(const struct perf_tool *tool,
 			union perf_event *event,
 			struct perf_sample *sample,
 			struct machine *machine)
···
  * guest events up to the same time. Finally write out the FINISHED_ROUND event
  * itself.
  */
-static int host__finished_round(struct perf_tool *tool,
+static int host__finished_round(const struct perf_tool *tool,
 				union perf_event *event,
 				struct ordered_events *oe)
 {
···
 	return perf_event__repipe_oe_synth(tool, event, oe);
 }
 
-static int host__context_switch(struct perf_tool *tool,
+static int host__context_switch(const struct perf_tool *tool,
 				union perf_event *event,
 				struct perf_sample *sample,
 				struct machine *machine)
···
 	return 0;
 }
 
-static int drop_sample(struct perf_tool *tool __maybe_unused,
+static int drop_sample(const struct perf_tool *tool __maybe_unused,
 		       union perf_event *event __maybe_unused,
 		       struct perf_sample *sample __maybe_unused,
 		       struct evsel *evsel __maybe_unused,

tools/perf/builtin-kmem.c

···
 typedef int (*tracepoint_handler)(struct evsel *evsel,
 				  struct perf_sample *sample);
 
-static int process_sample_event(struct perf_tool *tool __maybe_unused,
+static int process_sample_event(const struct perf_tool *tool __maybe_unused,
 				union perf_event *event,
 				struct perf_sample *sample,
 				struct evsel *evsel,
···
 
 	return ret;
 }
-

tools/perf/builtin-kvm.c

···
 }
 
 #if defined(HAVE_TIMERFD_SUPPORT) && defined(HAVE_LIBTRACEEVENT)
-static int process_lost_event(struct perf_tool *tool,
+static int process_lost_event(const struct perf_tool *tool,
 			      union perf_event *event __maybe_unused,
 			      struct perf_sample *sample __maybe_unused,
 			      struct machine *machine __maybe_unused)
···
 	return false;
 }
 
-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,

tools/perf/builtin-kwork.c

···
 }
 
 static struct kwork_class kwork_irq;
-static int process_irq_handler_entry_event(struct perf_tool *tool,
+static int process_irq_handler_entry_event(const struct perf_tool *tool,
 					   struct evsel *evsel,
 					   struct perf_sample *sample,
 					   struct machine *machine)
···
 	return 0;
 }
 
-static int process_irq_handler_exit_event(struct perf_tool *tool,
+static int process_irq_handler_exit_event(const struct perf_tool *tool,
 					  struct evsel *evsel,
 					  struct perf_sample *sample,
 					  struct machine *machine)
···
 };
 
 static struct kwork_class kwork_softirq;
-static int process_softirq_raise_event(struct perf_tool *tool,
+static int process_softirq_raise_event(const struct perf_tool *tool,
 				       struct evsel *evsel,
 				       struct perf_sample *sample,
 				       struct machine *machine)
···
 	return 0;
 }
 
-static int process_softirq_entry_event(struct perf_tool *tool,
+static int process_softirq_entry_event(const struct perf_tool *tool,
 				       struct evsel *evsel,
 				       struct perf_sample *sample,
 				       struct machine *machine)
···
 	return 0;
 }
 
-static int process_softirq_exit_event(struct perf_tool *tool,
+static int process_softirq_exit_event(const struct perf_tool *tool,
 				      struct evsel *evsel,
 				      struct perf_sample *sample,
 				      struct machine *machine)
···
 };
 
 static struct kwork_class kwork_workqueue;
-static int process_workqueue_activate_work_event(struct perf_tool *tool,
+static int process_workqueue_activate_work_event(const struct perf_tool *tool,
 						 struct evsel *evsel,
 						 struct perf_sample *sample,
 						 struct machine *machine)
···
 	return 0;
 }
 
-static int process_workqueue_execute_start_event(struct perf_tool *tool,
+static int process_workqueue_execute_start_event(const struct perf_tool *tool,
 						 struct evsel *evsel,
 						 struct perf_sample *sample,
 						 struct machine *machine)
···
 	return 0;
 }
 
-static int process_workqueue_execute_end_event(struct perf_tool *tool,
+static int process_workqueue_execute_end_event(const struct perf_tool *tool,
 					       struct evsel *evsel,
 					       struct perf_sample *sample,
 					       struct machine *machine)
···
 };
 
 static struct kwork_class kwork_sched;
-static int process_sched_switch_event(struct perf_tool *tool,
+static int process_sched_switch_event(const struct perf_tool *tool,
 				      struct evsel *evsel,
 				      struct perf_sample *sample,
 				      struct machine *machine)
···
 	return 0;
 }
 
-typedef int (*tracepoint_handler)(struct perf_tool *tool,
+typedef int (*tracepoint_handler)(const struct perf_tool *tool,
 				  struct evsel *evsel,
 				  struct perf_sample *sample,
 				  struct machine *machine);
 
-static int perf_kwork__process_tracepoint_sample(struct perf_tool *tool,
+static int perf_kwork__process_tracepoint_sample(const struct perf_tool *tool,
 						 union perf_event *event __maybe_unused,
 						 struct perf_sample *sample,
 						 struct evsel *evsel,

tools/perf/builtin-lock.c

···
 	{ "lock:contention_end",   evsel__process_contention_end,   },
 };
 
-static int process_event_update(struct perf_tool *tool,
+static int process_event_update(const struct perf_tool *tool,
 				union perf_event *event,
 				struct evlist **pevlist)
 {
···
 typedef int (*tracepoint_handler)(struct evsel *evsel,
 				  struct perf_sample *sample);
 
-static int process_sample_event(struct perf_tool *tool __maybe_unused,
+static int process_sample_event(const struct perf_tool *tool __maybe_unused,
 				union perf_event *event,
 				struct perf_sample *sample,
 				struct evsel *evsel,

tools/perf/builtin-mem.c

···
 }
 
 static int
-dump_raw_samples(struct perf_tool *tool,
+dump_raw_samples(const struct perf_tool *tool,
 		 union perf_event *event,
 		 struct perf_sample *sample,
 		 struct machine *machine)
···
 	return 0;
 }
 
-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 __maybe_unused,

tools/perf/builtin-record.c

···
 	return rec->opts.comp_level > 0;
 }
 
-static int process_synthesized_event(struct perf_tool *tool,
+static int process_synthesized_event(const struct perf_tool *tool,
 				     union perf_event *event,
 				     struct perf_sample *sample __maybe_unused,
 				     struct machine *machine __maybe_unused)
···
 
 static struct mutex synth_lock;
 
-static int process_locked_synthesized_event(struct perf_tool *tool,
+static int process_locked_synthesized_event(const struct perf_tool *tool,
 				     union perf_event *event,
 				     struct perf_sample *sample __maybe_unused,
 				     struct machine *machine __maybe_unused)
···
 
 #ifdef HAVE_AUXTRACE_SUPPORT
 
-static int record__process_auxtrace(struct perf_tool *tool,
+static int record__process_auxtrace(const struct perf_tool *tool,
 				    struct mmap *map,
 				    union perf_event *event, void *data1,
 				    size_t len1, void *data2, size_t len2)
···
 		rec->evlist->last_sample_time = sample_time;
 }
 
-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,
···
 };
 const char * const *record_usage = __record_usage;
 
-static int build_id__process_mmap(struct perf_tool *tool, union perf_event *event,
+static int build_id__process_mmap(const struct perf_tool *tool, union perf_event *event,
 				  struct perf_sample *sample, struct machine *machine)
 {
 	/*
···
 	return perf_event__process_mmap(tool, event, sample, machine);
 }
 
-static int build_id__process_mmap2(struct perf_tool *tool, union perf_event *event,
+static int build_id__process_mmap2(const struct perf_tool *tool, union perf_event *event,
 				   struct perf_sample *sample, struct machine *machine)
 {
 	/*
···
 	return perf_event__process_mmap2(tool, event, sample, machine);
 }
 
-static int process_timestamp_boundary(struct perf_tool *tool,
+static int process_timestamp_boundary(const struct perf_tool *tool,
 				      union perf_event *event __maybe_unused,
 				      struct perf_sample *sample,
 				      struct machine *machine __maybe_unused)

tools/perf/builtin-report.c

···
 	return 0;
 }
 
-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,
···
 	return ret;
 }
 
-static int process_read_event(struct perf_tool *tool,
+static int process_read_event(const struct perf_tool *tool,
 			      union perf_event *event,
 			      struct perf_sample *sample __maybe_unused,
 			      struct evsel *evsel,
···
 	ui_progress__finish();
 }
 
-static int count_sample_event(struct perf_tool *tool __maybe_unused,
+static int count_sample_event(const struct perf_tool *tool __maybe_unused,
 			      union perf_event *event __maybe_unused,
 			      struct perf_sample *sample __maybe_unused,
 			      struct evsel *evsel,
···
 	return 0;
 }
 
-static int count_lost_samples_event(struct perf_tool *tool,
+static int count_lost_samples_event(const struct perf_tool *tool,
 				    union perf_event *event,
 				    struct perf_sample *sample,
 				    struct machine *machine __maybe_unused)
···
 	return 0;
 }
 
-static int process_attr(struct perf_tool *tool __maybe_unused,
+static int process_attr(const struct perf_tool *tool __maybe_unused,
 			union perf_event *event,
 			struct evlist **pevlist);
 
···
 	return 0;
 }
 
-static int process_attr(struct perf_tool *tool __maybe_unused,
+static int process_attr(const struct perf_tool *tool __maybe_unused,
 			union perf_event *event,
 			struct evlist **pevlist)
 {

tools/perf/builtin-sched.c

···
 	}
 }
 
-static int process_sched_wakeup_event(struct perf_tool *tool,
+static int process_sched_wakeup_event(const struct perf_tool *tool,
 				      struct evsel *evsel,
 				      struct perf_sample *sample,
 				      struct machine *machine)
···
 	return 0;
 }
 
-static int process_sched_wakeup_ignore(struct perf_tool *tool __maybe_unused,
+static int process_sched_wakeup_ignore(const struct perf_tool *tool __maybe_unused,
 				      struct evsel *evsel __maybe_unused,
 				      struct perf_sample *sample __maybe_unused,
 				      struct machine *machine __maybe_unused)
···
 	return 0;
 }
 
-static int process_sched_switch_event(struct perf_tool *tool,
+static int process_sched_switch_event(const struct perf_tool *tool,
 				      struct evsel *evsel,
 				      struct perf_sample *sample,
 				      struct machine *machine)
···
 	return err;
 }
 
-static int process_sched_runtime_event(struct perf_tool *tool,
+static int process_sched_runtime_event(const struct perf_tool *tool,
 				       struct evsel *evsel,
 				       struct perf_sample *sample,
 				       struct machine *machine)
···
 	return 0;
 }
 
-static int perf_sched__process_fork_event(struct perf_tool *tool,
+static int perf_sched__process_fork_event(const struct perf_tool *tool,
 					  union perf_event *event,
 					  struct perf_sample *sample,
 					  struct machine *machine)
···
 	return 0;
 }
 
-static int process_sched_migrate_task_event(struct perf_tool *tool,
+static int process_sched_migrate_task_event(const struct perf_tool *tool,
 					    struct evsel *evsel,
 					    struct perf_sample *sample,
 					    struct machine *machine)
···
 	return 0;
 }
 
-typedef int (*tracepoint_handler)(struct perf_tool *tool,
+typedef int (*tracepoint_handler)(const struct perf_tool *tool,
 				  struct evsel *evsel,
 				  struct perf_sample *sample,
 				  struct machine *machine);
 
-static int perf_sched__process_tracepoint_sample(struct perf_tool *tool __maybe_unused,
+static int perf_sched__process_tracepoint_sample(const struct perf_tool *tool __maybe_unused,
 						 union perf_event *event __maybe_unused,
 						 struct perf_sample *sample,
 						 struct evsel *evsel,
···
 	return err;
 }
 
-static int perf_sched__process_comm(struct perf_tool *tool __maybe_unused,
+static int perf_sched__process_comm(const struct perf_tool *tool __maybe_unused,
 				    union perf_event *event,
 				    struct perf_sample *sample,
 				    struct machine *machine)
···
 	printf("\n");
 }
 
-static int timehist_sched_wakeup_ignore(struct perf_tool *tool __maybe_unused,
+static int timehist_sched_wakeup_ignore(const struct perf_tool *tool __maybe_unused,
 					union perf_event *event __maybe_unused,
 					struct evsel *evsel __maybe_unused,
 					struct perf_sample *sample __maybe_unused,
···
 	return 0;
 }
 
-static int timehist_sched_wakeup_event(struct perf_tool *tool,
+static int timehist_sched_wakeup_event(const struct perf_tool *tool,
 				       union perf_event *event __maybe_unused,
 				       struct evsel *evsel,
 				       struct perf_sample *sample,
···
 	printf("\n");
 }
 
-static int timehist_migrate_task_event(struct perf_tool *tool,
+static int timehist_migrate_task_event(const struct perf_tool *tool,
 				       union perf_event *event __maybe_unused,
 				       struct evsel *evsel,
 				       struct perf_sample *sample,
···
 	return 0;
 }
 
-static int timehist_sched_change_event(struct perf_tool *tool,
+static int timehist_sched_change_event(const struct perf_tool *tool,
 				       union perf_event *event,
 				       struct evsel *evsel,
 				       struct perf_sample *sample,
···
 	return rc;
 }
 
-static int timehist_sched_switch_event(struct perf_tool *tool,
+static int timehist_sched_switch_event(const struct perf_tool *tool,
 			     union perf_event *event,
 			     struct evsel *evsel,
 			     struct perf_sample *sample,
···
 	return timehist_sched_change_event(tool, event, evsel, sample, machine);
 }
 
-static int process_lost(struct perf_tool *tool __maybe_unused,
+static int process_lost(const struct perf_tool *tool __maybe_unused,
 			union perf_event *event,
 			struct perf_sample *sample,
 			struct machine *machine __maybe_unused)
···
 	printf(" (x %d)\n", sched->max_cpu.cpu);
 }
 
-typedef int (*sched_handler)(struct perf_tool *tool,
+typedef int (*sched_handler)(const struct perf_tool *tool,
 			  union perf_event *event,
 			  struct evsel *evsel,
 			  struct perf_sample *sample,
 			  struct machine *machine);
 
-static int perf_timehist__process_sample(struct perf_tool *tool,
+static int perf_timehist__process_sample(const struct perf_tool *tool,
 					 union perf_event *event,
 					 struct perf_sample *sample,
 					 struct evsel *evsel,

tools/perf/builtin-script.c

···
 	return false;
 }
 
-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,
···
 // Used when scr->per_event_dump is not set
 static struct evsel_script es_stdout;
 
-static int process_attr(struct perf_tool *tool, union perf_event *event,
+static int process_attr(const struct perf_tool *tool, union perf_event *event,
 			struct evlist **pevlist)
 {
 	struct perf_script *scr = container_of(tool, struct perf_script, tool);
···
 	return 0;
 }
 
-static int print_event_with_time(struct perf_tool *tool,
+static int print_event_with_time(const struct perf_tool *tool,
 				 union perf_event *event,
 				 struct perf_sample *sample,
 				 struct machine *machine,
···
 	return 0;
 }
 
-static int print_event(struct perf_tool *tool, union perf_event *event,
+static int print_event(const struct perf_tool *tool, union perf_event *event,
 		       struct perf_sample *sample, struct machine *machine,
 		       pid_t pid, pid_t tid)
 {
 	return print_event_with_time(tool, event, sample, machine, pid, tid, 0);
 }
 
-static int process_comm_event(struct perf_tool *tool,
+static int process_comm_event(const struct perf_tool *tool,
 			      union perf_event *event,
 			      struct perf_sample *sample,
 			      struct machine *machine)
···
 			   event->comm.tid);
 }
 
-static int process_namespaces_event(struct perf_tool *tool,
+static int process_namespaces_event(const struct perf_tool *tool,
 				    union perf_event *event,
 				    struct perf_sample *sample,
 				    struct machine *machine)
···
 			   event->namespaces.tid);
 }
 
-static int process_cgroup_event(struct perf_tool *tool,
+static int process_cgroup_event(const struct perf_tool *tool,
 				union perf_event *event,
 				struct perf_sample *sample,
 				struct machine *machine)
···
 			    sample->tid);
 }
 
-static int process_fork_event(struct perf_tool *tool,
+static int process_fork_event(const struct perf_tool *tool,
 			      union perf_event *event,
 			      struct perf_sample *sample,
 			      struct machine *machine)
···
 				     event->fork.pid, event->fork.tid,
 				     event->fork.time);
 }
-static int process_exit_event(struct perf_tool *tool,
+static int process_exit_event(const struct perf_tool *tool,
 			      union perf_event *event,
 			      struct perf_sample *sample,
 			      struct machine *machine)
···
 	return perf_event__process_exit(tool, event, sample, machine);
 }
 
-static int process_mmap_event(struct perf_tool *tool,
+static int process_mmap_event(const struct perf_tool *tool,
 			      union perf_event *event,
 			      struct perf_sample *sample,
 			      struct machine *machine)
···
 			   event->mmap.tid);
 }
 
-static int process_mmap2_event(struct perf_tool *tool,
+static int process_mmap2_event(const struct perf_tool *tool,
 			      union perf_event *event,
 			      struct perf_sample *sample,
 			      struct machine *machine)
···
 			   event->mmap2.tid);
 }
 
-static int process_switch_event(struct perf_tool *tool,
+static int process_switch_event(const struct perf_tool *tool,
 				union perf_event *event,
 				struct perf_sample *sample,
 				struct machine *machine)
···
 }
 
 static int
-process_lost_event(struct perf_tool *tool,
+process_lost_event(const struct perf_tool *tool,
 		   union perf_event *event,
 		   struct perf_sample *sample,
 		   struct machine *machine)
···
 }
 
 static int
-process_throttle_event(struct perf_tool *tool __maybe_unused,
+process_throttle_event(const struct perf_tool *tool __maybe_unused,
 		       union perf_event *event,
 		       struct perf_sample *sample,
 		       struct machine *machine)
···
 }
 
 static int
-process_finished_round_event(struct perf_tool *tool __maybe_unused,
+process_finished_round_event(const struct perf_tool *tool __maybe_unused,
 			     union perf_event *event,
 			     struct ordered_events *oe __maybe_unused)
 
···
 }
 
 static int
-process_bpf_events(struct perf_tool *tool __maybe_unused,
+process_bpf_events(const struct perf_tool *tool __maybe_unused,
 		   union perf_event *event,
 		   struct perf_sample *sample,
 		   struct machine *machine)
···
 			   sample->tid);
 }
 
-static int process_text_poke_events(struct perf_tool *tool,
+static int process_text_poke_events(const struct perf_tool *tool,
 				    union perf_event *event,
 				    struct perf_sample *sample,
 				    struct machine *machine)
···
 int process_thread_map_event(struct perf_session *session,
 			     union perf_event *event)
 {
-	struct perf_tool *tool = session->tool;
+	const struct perf_tool *tool = session->tool;
 	struct perf_script *script = container_of(tool, struct perf_script, tool);
 
 	if (dump_trace)
···
 int process_cpu_map_event(struct perf_session *session,
 			  union perf_event *event)
 {
-	struct perf_tool *tool = session->tool;
+	const struct perf_tool *tool = session->tool;
 	struct perf_script *script = container_of(tool, struct perf_script, tool);
 
 	if (dump_trace)
···
 static int perf_script__process_auxtrace_info(struct perf_session *session,
 					      union perf_event *event)
 {
-	struct perf_tool *tool = session->tool;
-
 	int ret = perf_event__process_auxtrace_info(session, event);
 
 	if (ret == 0) {
+		const struct perf_tool *tool = session->tool;
 		struct perf_script *script = container_of(tool, struct perf_script, tool);
 
 		ret = perf_script__setup_per_event_dump(script);

tools/perf/builtin-stat.c

···
 	perf_stat__reset_shadow_stats();
 }
 
-static int process_synthesized_event(struct perf_tool *tool __maybe_unused,
+static int process_synthesized_event(const struct perf_tool *tool __maybe_unused,
 				     union perf_event *event,
 				     struct perf_sample *sample __maybe_unused,
 				     struct machine *machine __maybe_unused)
···
 int process_stat_config_event(struct perf_session *session,
 			      union perf_event *event)
 {
-	struct perf_tool *tool = session->tool;
+	const struct perf_tool *tool = session->tool;
 	struct perf_stat *st = container_of(tool, struct perf_stat, tool);
 
 	perf_event__read_stat_config(&stat_config, &event->stat_config);
···
 int process_thread_map_event(struct perf_session *session,
 			     union perf_event *event)
 {
-	struct perf_tool *tool = session->tool;
+	const struct perf_tool *tool = session->tool;
 	struct perf_stat *st = container_of(tool, struct perf_stat, tool);
 
 	if (st->threads) {
···
 int process_cpu_map_event(struct perf_session *session,
 			  union perf_event *event)
 {
-	struct perf_tool *tool = session->tool;
+	const struct perf_tool *tool = session->tool;
 	struct perf_stat *st = container_of(tool, struct perf_stat, tool);
 	struct perf_cpu_map *cpus;
 

tools/perf/builtin-timechart.c

···
 static u64 *cpus_pstate_start_times;
 static u64 *cpus_pstate_state;
 
-static int process_comm_event(struct perf_tool *tool,
+static int process_comm_event(const struct perf_tool *tool,
 			      union perf_event *event,
 			      struct perf_sample *sample __maybe_unused,
 			      struct machine *machine __maybe_unused)
···
 	return 0;
 }
 
-static int process_fork_event(struct perf_tool *tool,
+static int process_fork_event(const struct perf_tool *tool,
 			      union perf_event *event,
 			      struct perf_sample *sample __maybe_unused,
 			      struct machine *machine __maybe_unused)
···
 	return 0;
 }
 
-static int process_exit_event(struct perf_tool *tool,
+static int process_exit_event(const struct perf_tool *tool,
 			      union perf_event *event,
 			      struct perf_sample *sample __maybe_unused,
 			      struct machine *machine __maybe_unused)
···
 				  struct perf_sample *sample,
 				  const char *backtrace);
 
-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,

tools/perf/builtin-top.c

···
 	return 0;
 }
 
-static void perf_event__process_sample(struct perf_tool *tool,
+static void perf_event__process_sample(const struct perf_tool *tool,
 				       const union perf_event *event,
 				       struct evsel *evsel,
 				       struct perf_sample *sample,

tools/perf/builtin-trace.c

···
 	return ret;
 }
 
-static int trace__tool_process(struct perf_tool *tool,
+static int trace__tool_process(const struct perf_tool *tool,
 			       union perf_event *event,
 			       struct perf_sample *sample,
 			       struct machine *machine)
···
 		trace->base_time = sample->time;
 }
 
-static int trace__process_sample(struct perf_tool *tool,
+static int trace__process_sample(const struct perf_tool *tool,
 				 union perf_event *event,
 				 struct perf_sample *sample,
 				 struct evsel *evsel,

tools/perf/tests/cpumap.c

···
 
 struct machine;
 
-static int process_event_mask(struct perf_tool *tool __maybe_unused,
+static int process_event_mask(const struct perf_tool *tool __maybe_unused,
 			 union perf_event *event,
 			 struct perf_sample *sample __maybe_unused,
 			 struct machine *machine __maybe_unused)
···
 	return 0;
 }
 
-static int process_event_cpus(struct perf_tool *tool __maybe_unused,
+static int process_event_cpus(const struct perf_tool *tool __maybe_unused,
 			 union perf_event *event,
 			 struct perf_sample *sample __maybe_unused,
 			 struct machine *machine __maybe_unused)
···
 	return 0;
 }
 
-static int process_event_range_cpus(struct perf_tool *tool __maybe_unused,
+static int process_event_range_cpus(const struct perf_tool *tool __maybe_unused,
 				union perf_event *event,
 				struct perf_sample *sample __maybe_unused,
 				struct machine *machine __maybe_unused)

tools/perf/tests/dlfilter-test.c

···
 	return ret;
 }
 
-static int process(struct perf_tool *tool, union perf_event *event,
+static int process(const struct perf_tool *tool, union perf_event *event,
 		   struct perf_sample *sample __maybe_unused,
 		   struct machine *machine __maybe_unused)
 {

tools/perf/tests/dwarf-unwind.c

···
 #define NO_TAIL_CALL_BARRIER __asm__ __volatile__("" : : : "memory");
 #endif
 
-static int mmap_handler(struct perf_tool *tool __maybe_unused,
+static int mmap_handler(const struct perf_tool *tool __maybe_unused,
 			union perf_event *event,
 			struct perf_sample *sample,
 			struct machine *machine)

tools/perf/tests/event_update.c

···
 #include "tests.h"
 #include "debug.h"
 
-static int process_event_unit(struct perf_tool *tool __maybe_unused,
+static int process_event_unit(const struct perf_tool *tool __maybe_unused,
 			      union perf_event *event,
 			      struct perf_sample *sample __maybe_unused,
 			      struct machine *machine __maybe_unused)
···
 	return 0;
 }
 
-static int process_event_scale(struct perf_tool *tool __maybe_unused,
+static int process_event_scale(const struct perf_tool *tool __maybe_unused,
 			       union perf_event *event,
 			       struct perf_sample *sample __maybe_unused,
 			       struct machine *machine __maybe_unused)
···
 	const char *name;
 };
 
-static int process_event_name(struct perf_tool *tool,
+static int process_event_name(const struct perf_tool *tool,
 			      union perf_event *event,
 			      struct perf_sample *sample __maybe_unused,
 			      struct machine *machine __maybe_unused)
···
 	return 0;
 }
 
-static int process_event_cpus(struct perf_tool *tool __maybe_unused,
+static int process_event_cpus(const struct perf_tool *tool __maybe_unused,
 			      union perf_event *event,
 			      struct perf_sample *sample __maybe_unused,
 			      struct machine *machine __maybe_unused)

tools/perf/tests/stat.c

···
 	return false;
 }
 
-static int process_stat_config_event(struct perf_tool *tool __maybe_unused,
+static int process_stat_config_event(const struct perf_tool *tool __maybe_unused,
 				     union perf_event *event,
 				     struct perf_sample *sample __maybe_unused,
 				     struct machine *machine __maybe_unused)
···
 	return 0;
 }
 
-static int process_stat_event(struct perf_tool *tool __maybe_unused,
+static int process_stat_event(const struct perf_tool *tool __maybe_unused,
 			      union perf_event *event,
 			      struct perf_sample *sample __maybe_unused,
 			      struct machine *machine __maybe_unused)
···
 	return 0;
 }
 
-static int process_stat_round_event(struct perf_tool *tool __maybe_unused,
+static int process_stat_round_event(const struct perf_tool *tool __maybe_unused,
 				    union perf_event *event,
 				    struct perf_sample *sample __maybe_unused,
 				    struct machine *machine __maybe_unused)

tools/perf/tests/thread-map.c

···
 	return 0;
 }
 
-static int process_event(struct perf_tool *tool __maybe_unused,
+static int process_event(const struct perf_tool *tool __maybe_unused,
 			 union perf_event *event,
 			 struct perf_sample *sample __maybe_unused,
 			 struct machine *machine __maybe_unused)

tools/perf/util/arm-spe.c

···
 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;
···
 
 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);
···
 }
 
 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);

tools/perf/util/auxtrace.c

···
 }
 
 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)
 {
···
 
 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;
···
 }
 
 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);
···
 }
 
 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;
···
 	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;

tools/perf/util/auxtrace.h

···
 	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,
···
 				   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);
···
 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,
···
 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;
 }
···
 
 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;
 }

tools/perf/util/bpf-event.c

···
 {
 	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;
···
 	union perf_event	*event;
 	perf_event__handler_t	 process;
 	struct machine		*machine;
-	struct perf_tool	*tool;
+	const struct perf_tool	*tool;
 };
 
 static int

tools/perf/util/build-id.c

···
 
 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,
···
 	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,

tools/perf/util/build-id.h

···
 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);
 

tools/perf/util/cs-etm.c

···
 }
 
 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,
···
 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,
···
 
 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,

tools/perf/util/data-convert-bt.c

···
 	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,
···
 } 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)	\

tools/perf/util/data-convert-json.c

···
 	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);
···
 	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,

tools/perf/util/event.c

···
 		       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)
···
 	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)
···
 	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)
···
 	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)
···
 	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)
···
 	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)
···
 	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)
···
 	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)
···
 	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)
···
 	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)
···
 	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)
···
 	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)
···
 	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)
···
 	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)
···
 		       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)
···
 	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)
···
 	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)

tools/perf/util/event.h

···
 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);

tools/perf/util/header.c

···
 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;
···
 	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)
 {
···
 	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)
 {

tools/perf/util/header.h

···
 
 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);

tools/perf/util/hisi-ptt.c

···
 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);
···
 }
 
 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;
 }

tools/perf/util/intel-bts.c

···
 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);
···
 
 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);
···
 }
 
 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);

tools/perf/util/intel-pt.c

···
 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);
···
 	return err;
 }
 
-static int intel_pt_flush(struct perf_session *session, struct perf_tool *tool)
+static int intel_pt_flush(struct perf_session *session, const struct perf_tool *tool)
 {
 	struct intel_pt *pt = container_of(session->auxtrace, struct intel_pt,
 					   auxtrace);
···
 
 static int intel_pt_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_pt *pt = container_of(session->auxtrace, struct intel_pt,
 					   auxtrace);

tools/perf/util/jitdump.c

···
 {
 	struct perf_sample sample;
 	union perf_event *event;
-	struct perf_tool *tool = jd->session->tool;
+	const struct perf_tool *tool = jd->session->tool;
 	uint64_t code, addr;
 	uintptr_t uaddr;
 	char *filename;
···
 {
 	struct perf_sample sample;
 	union perf_event *event;
-	struct perf_tool *tool = jd->session->tool;
+	const struct perf_tool *tool = jd->session->tool;
 	char *filename;
 	size_t size;
 	struct stat st;

tools/perf/util/s390-cpumsf.c

···
 s390_cpumsf_process_event(struct perf_session *session,
 			  union perf_event *event,
 			  struct perf_sample *sample,
-			  struct perf_tool *tool)
+			  const struct perf_tool *tool)
 {
 	struct s390_cpumsf *sf = container_of(session->auxtrace,
 					      struct s390_cpumsf,
···
 static int
 s390_cpumsf_process_auxtrace_event(struct perf_session *session,
 				   union perf_event *event __maybe_unused,
-				   struct perf_tool *tool __maybe_unused)
+				   const struct perf_tool *tool __maybe_unused)
 {
 	struct s390_cpumsf *sf = container_of(session->auxtrace,
 					      struct s390_cpumsf,
···
 }
 
 static int s390_cpumsf_flush(struct perf_session *session __maybe_unused,
-			     struct perf_tool *tool __maybe_unused)
+			     const struct perf_tool *tool __maybe_unused)
 {
 	return 0;
 }

tools/perf/util/session.c

···
 
 static int perf_session__deliver_event(struct perf_session *session,
 				       union perf_event *event,
-				       struct perf_tool *tool,
+				       const struct perf_tool *tool,
 				       u64 file_offset,
 				       const char *file_path);
 
···
 	return 0;
 }
 
-static int process_event_synth_attr_stub(struct perf_tool *tool __maybe_unused,
+static int process_event_synth_attr_stub(const struct perf_tool *tool __maybe_unused,
 					 union perf_event *event __maybe_unused,
 					 struct evlist **pevlist
 					 __maybe_unused)
···
 	return 0;
 }
 
-static int process_event_synth_event_update_stub(struct perf_tool *tool __maybe_unused,
+static int process_event_synth_event_update_stub(const struct perf_tool *tool __maybe_unused,
 						 union perf_event *event __maybe_unused,
 						 struct evlist **pevlist
 						 __maybe_unused)
···
 	return 0;
 }
 
-static int process_event_sample_stub(struct perf_tool *tool __maybe_unused,
+static int process_event_sample_stub(const struct perf_tool *tool __maybe_unused,
 				     union perf_event *event __maybe_unused,
 				     struct perf_sample *sample __maybe_unused,
 				     struct evsel *evsel __maybe_unused,
···
 	return 0;
 }
 
-static int process_event_stub(struct perf_tool *tool __maybe_unused,
+static int process_event_stub(const struct perf_tool *tool __maybe_unused,
 			      union perf_event *event __maybe_unused,
 			      struct perf_sample *sample __maybe_unused,
 			      struct machine *machine __maybe_unused)
···
 	return 0;
 }
 
-static int process_finished_round_stub(struct perf_tool *tool __maybe_unused,
+static int process_finished_round_stub(const struct perf_tool *tool __maybe_unused,
 				       union perf_event *event __maybe_unused,
 				       struct ordered_events *oe __maybe_unused)
 {
···
  *      Flush every events below timestamp 7
  *      etc...
  */
-int perf_event__process_finished_round(struct perf_tool *tool __maybe_unused,
+int perf_event__process_finished_round(const struct perf_tool *tool __maybe_unused,
 				       union perf_event *event __maybe_unused,
 				       struct ordered_events *oe)
 {
···
 }
 
 static int deliver_sample_value(struct evlist *evlist,
-				struct perf_tool *tool,
+				const struct perf_tool *tool,
 				union perf_event *event,
 				struct perf_sample *sample,
 				struct sample_read_value *v,
···
 }
 
 static int deliver_sample_group(struct evlist *evlist,
-				struct perf_tool *tool,
+				const struct perf_tool *tool,
 				union  perf_event *event,
 				struct perf_sample *sample,
 				struct machine *machine,
···
 	return ret;
 }
 
-static int evlist__deliver_sample(struct evlist *evlist, struct perf_tool *tool,
+static int evlist__deliver_sample(struct evlist *evlist, const struct perf_tool *tool,
 				  union  perf_event *event, struct perf_sample *sample,
 				  struct evsel *evsel, struct machine *machine)
 {
···
 				   struct evlist *evlist,
 				   union perf_event *event,
 				   struct perf_sample *sample,
-				   struct perf_tool *tool, u64 file_offset,
+				   const struct perf_tool *tool, u64 file_offset,
 				   const char *file_path)
 {
 	struct evsel *evsel;
···
 
 static int perf_session__deliver_event(struct perf_session *session,
 				       union perf_event *event,
-				       struct perf_tool *tool,
+				       const struct perf_tool *tool,
 				       u64 file_offset,
 				       const char *file_path)
 {
···
 					    const char *file_path)
 {
 	struct ordered_events *oe = &session->ordered_events;
-	struct perf_tool *tool = session->tool;
+	const struct perf_tool *tool = session->tool;
 	struct perf_sample sample = { .time = 0, };
 	int fd = perf_data__fd(session->data);
 	int err;
···
 				      struct perf_sample *sample)
 {
 	struct evlist *evlist = session->evlist;
-	struct perf_tool *tool = session->tool;
+	const struct perf_tool *tool = session->tool;
 
 	events_stats__inc(&evlist->stats, event->header.type);
 
···
 				       const char *file_path)
 {
 	struct evlist *evlist = session->evlist;
-	struct perf_tool *tool = session->tool;
+	const struct perf_tool *tool = session->tool;
 	int ret;
 
 	if (session->header.needs_swap)

tools/perf/util/session.h

···
 int perf_event__process_id_index(struct perf_session *session,
 				 union perf_event *event);
 
-int perf_event__process_finished_round(struct perf_tool *tool,
+int perf_event__process_finished_round(const struct perf_tool *tool,
 				       union perf_event *event,
 				       struct ordered_events *oe);
 

tools/perf/util/synthetic-events.c

···
-// SPDX-License-Identifier: GPL-2.0-only 
+// SPDX-License-Identifier: GPL-2.0-only
 
 #include "util/cgroup.h"
 #include "util/data.h"
···
 
 unsigned int proc_map_timeout = DEFAULT_PROC_MAP_PARSE_TIMEOUT;
 
-int perf_tool__process_synth_event(struct perf_tool *tool,
+int perf_tool__process_synth_event(const struct perf_tool *tool,
 				   union perf_event *event,
 				   struct machine *machine,
 				   perf_event__handler_t process)
···
 	return 0;
 }
 
-pid_t perf_event__synthesize_comm(struct perf_tool *tool,
+pid_t perf_event__synthesize_comm(const struct perf_tool *tool,
 					 union perf_event *event, pid_t pid,
 					 perf_event__handler_t process,
 					 struct machine *machine)
···
 	}
 }
 
-int perf_event__synthesize_namespaces(struct perf_tool *tool,
+int perf_event__synthesize_namespaces(const struct perf_tool *tool,
 				      union perf_event *event,
 				      pid_t pid, pid_t tgid,
 				      perf_event__handler_t process,
···
 	return 0;
 }
 
-static int perf_event__synthesize_fork(struct perf_tool *tool,
+static int perf_event__synthesize_fork(const struct perf_tool *tool,
 				       union perf_event *event,
 				       pid_t pid, pid_t tgid, pid_t ppid,
 				       perf_event__handler_t process,
···
 	dso__put(dso);
 }
 
-int perf_event__synthesize_mmap_events(struct perf_tool *tool,
+int perf_event__synthesize_mmap_events(const struct perf_tool *tool,
 				       union perf_event *event,
 				       pid_t pid, pid_t tgid,
 				       perf_event__handler_t process,
···
 }
 
 #ifdef HAVE_FILE_HANDLE
-static int perf_event__synthesize_cgroup(struct perf_tool *tool,
+static int perf_event__synthesize_cgroup(const struct perf_tool *tool,
 					 union perf_event *event,
 					 char *path, size_t mount_len,
 					 perf_event__handler_t process,
···
 	return 0;
 }
 
-static int perf_event__walk_cgroup_tree(struct perf_tool *tool,
+static int perf_event__walk_cgroup_tree(const struct perf_tool *tool,
 					union perf_event *event,
 					char *path, size_t mount_len,
 					perf_event__handler_t process,
···
 	return ret;
 }
 
-int perf_event__synthesize_cgroups(struct perf_tool *tool,
+int perf_event__synthesize_cgroups(const struct perf_tool *tool,
 				   perf_event__handler_t process,
 				   struct machine *machine)
 {
···
 	return 0;
 }
 #else
-int perf_event__synthesize_cgroups(struct perf_tool *tool __maybe_unused,
+int perf_event__synthesize_cgroups(const struct perf_tool *tool __maybe_unused,
 				   perf_event__handler_t process __maybe_unused,
 				   struct machine *machine __maybe_unused)
 {
···
 #endif
 
 struct perf_event__synthesize_modules_maps_cb_args {
-	struct perf_tool *tool;
+	const struct perf_tool *tool;
 	perf_event__handler_t process;
 	struct machine *machine;
 	union perf_event *event;
···
 	return 0;
 }
 
-int perf_event__synthesize_modules(struct perf_tool *tool, perf_event__handler_t process,
+int perf_event__synthesize_modules(const struct perf_tool *tool, perf_event__handler_t process,
 				   struct machine *machine)
 {
 	int rc;
···
 				      union perf_event *fork_event,
 				      union perf_event *namespaces_event,
 				      pid_t pid, int full, perf_event__handler_t process,
-				      struct perf_tool *tool, struct machine *machine,
+				      const struct perf_tool *tool, struct machine *machine,
 				      bool needs_mmap, bool mmap_data)
 {
 	char filename[PATH_MAX];
···
 	return rc;
 }
 
-int perf_event__synthesize_thread_map(struct perf_tool *tool,
+int perf_event__synthesize_thread_map(const struct perf_tool *tool,
 				      struct perf_thread_map *threads,
 				      perf_event__handler_t process,
 				      struct machine *machine,
···
 	return err;
 }
 
-static int __perf_event__synthesize_threads(struct perf_tool *tool,
+static int __perf_event__synthesize_threads(const struct perf_tool *tool,
 					    perf_event__handler_t process,
 					    struct machine *machine,
 					    bool needs_mmap,
···
 }
 
 struct synthesize_threads_arg {
-	struct perf_tool *tool;
+	const struct perf_tool *tool;
 	perf_event__handler_t process;
 	struct machine *machine;
 	bool needs_mmap;
···
 	return NULL;
 }
 
-int perf_event__synthesize_threads(struct perf_tool *tool,
+int perf_event__synthesize_threads(const struct perf_tool *tool,
 				   perf_event__handler_t process,
 				   struct machine *machine,
 				   bool needs_mmap, bool mmap_data,
···
 	return err;
 }
 
-int __weak perf_event__synthesize_extra_kmaps(struct perf_tool *tool __maybe_unused,
+int __weak perf_event__synthesize_extra_kmaps(const struct perf_tool *tool __maybe_unused,
 					      perf_event__handler_t process __maybe_unused,
 					      struct machine *machine __maybe_unused)
 {
 	return 0;
 }
 
-static int __perf_event__synthesize_kernel_mmap(struct perf_tool *tool,
+static int __perf_event__synthesize_kernel_mmap(const struct perf_tool *tool,
 						perf_event__handler_t process,
 						struct machine *machine)
 {
···
 	return err;
 }
 
-int perf_event__synthesize_kernel_mmap(struct perf_tool *tool,
+int perf_event__synthesize_kernel_mmap(const struct perf_tool *tool,
 				       perf_event__handler_t process,
 				       struct machine *machine)
 {
···
 	return perf_event__synthesize_extra_kmaps(tool, process, machine);
 }
 
-int perf_event__synthesize_thread_map2(struct perf_tool *tool,
+int perf_event__synthesize_thread_map2(const struct perf_tool *tool,
 				      struct perf_thread_map *threads,
 				      perf_event__handler_t process,
 				      struct machine *machine)
···
 }
 
 
-int perf_event__synthesize_cpu_map(struct perf_tool *tool,
+int perf_event__synthesize_cpu_map(const struct perf_tool *tool,
 				   const struct perf_cpu_map *map,
 				   perf_event__handler_t process,
 				   struct machine *machine)
···
 	return err;
 }
 
-int perf_event__synthesize_stat_config(struct perf_tool *tool,
+int perf_event__synthesize_stat_config(const struct perf_tool *tool,
 				       struct perf_stat_config *config,
 				       perf_event__handler_t process,
 				       struct machine *machine)
···
 	return err;
 }
 
-int perf_event__synthesize_stat(struct perf_tool *tool,
+int perf_event__synthesize_stat(const struct perf_tool *tool,
 				struct perf_cpu cpu, u32 thread, u64 id,
 				struct perf_counts_values *count,
 				perf_event__handler_t process,
···
 	return process(tool, (union perf_event *) &event, NULL, machine);
 }
 
-int perf_event__synthesize_stat_round(struct perf_tool *tool,
+int perf_event__synthesize_stat_round(const struct perf_tool *tool,
 				      u64 evtime, u64 type,
 				      perf_event__handler_t process,
 				      struct machine *machine)
···
 	return (void *)array - (void *)start;
 }
 
-int __perf_event__synthesize_id_index(struct perf_tool *tool, perf_event__handler_t process,
+int __perf_event__synthesize_id_index(const struct perf_tool *tool, perf_event__handler_t process,
 				      struct evlist *evlist, struct machine *machine, size_t from)
 {
 	union perf_event *ev;
···
 	return err;
 }
 
-int perf_event__synthesize_id_index(struct perf_tool *tool, perf_event__handler_t process,
+int perf_event__synthesize_id_index(const struct perf_tool *tool, perf_event__handler_t process,
 				    struct evlist *evlist, struct machine *machine)
 {
 	return __perf_event__synthesize_id_index(tool, process, evlist, machine, 0);
 }
 
-int __machine__synthesize_threads(struct machine *machine, struct perf_tool *tool,
+int __machine__synthesize_threads(struct machine *machine, const struct perf_tool *tool,
 				  struct target *target, struct perf_thread_map *threads,
 				  perf_event__handler_t process, bool needs_mmap,
 				  bool data_mmap, unsigned int nr_threads_synthesize)
···
 	return ev;
 }
 
-int perf_event__synthesize_event_update_unit(struct perf_tool *tool, struct evsel *evsel,
+int perf_event__synthesize_event_update_unit(const struct perf_tool *tool, struct evsel *evsel,
 					     perf_event__handler_t process)
 {
 	size_t size = strlen(evsel->unit);
···
 	return err;
 }
 
-int perf_event__synthesize_event_update_scale(struct perf_tool *tool, struct evsel *evsel,
+int perf_event__synthesize_event_update_scale(const struct perf_tool *tool, struct evsel *evsel,
 					      perf_event__handler_t process)
 {
 	struct perf_record_event_update *ev;
···
 	return err;
 }
 
-int perf_event__synthesize_event_update_name(struct perf_tool *tool, struct evsel *evsel,
+int perf_event__synthesize_event_update_name(const struct perf_tool *tool, struct evsel *evsel,
 					     perf_event__handler_t process)
 {
 	struct perf_record_event_update *ev;
···
 	return err;
 }
 
-int perf_event__synthesize_event_update_cpus(struct perf_tool *tool, struct evsel *evsel,
+int perf_event__synthesize_event_update_cpus(const struct perf_tool *tool, struct evsel *evsel,
 					     perf_event__handler_t process)
 {
 	struct synthesize_cpu_map_data syn_data = { .map = evsel->core.own_cpus };
···
 	return err;
 }
 
-int perf_event__synthesize_attrs(struct perf_tool *tool, struct evlist *evlist,
+int perf_event__synthesize_attrs(const struct perf_tool *tool, struct evlist *evlist,
 				 perf_event__handler_t process)
 {
 	struct evsel *evsel;
···
 	return evsel->scale != 1;
 }
 
-int perf_event__synthesize_extra_attr(struct perf_tool *tool, struct evlist *evsel_list,
+int perf_event__synthesize_extra_attr(const struct perf_tool *tool, struct evlist *evsel_list,
 				      perf_event__handler_t process, bool is_pipe)
 {
 	struct evsel *evsel;
···
 	return 0;
 }
 
-int perf_event__synthesize_attr(struct perf_tool *tool, struct perf_event_attr *attr,
+int perf_event__synthesize_attr(const struct perf_tool *tool, struct perf_event_attr *attr,
 				u32 ids, u64 *id, perf_event__handler_t process)
 {
 	union perf_event *ev;
···
 }
 
 #ifdef HAVE_LIBTRACEEVENT
-int perf_event__synthesize_tracing_data(struct perf_tool *tool, int fd, struct evlist *evlist,
+int perf_event__synthesize_tracing_data(const struct perf_tool *tool, int fd, struct evlist *evlist,
 					perf_event__handler_t process)
 {
 	union perf_event ev;
···
 }
 #endif
 
-int perf_event__synthesize_build_id(struct perf_tool *tool, struct dso *pos, u16 misc,
+int perf_event__synthesize_build_id(const struct perf_tool *tool, struct dso *pos, u16 misc,
 				    perf_event__handler_t process, struct machine *machine)
 {
 	union perf_event ev;
···
 	return process(tool, &ev, NULL, machine);
 }
 
-int perf_event__synthesize_stat_events(struct perf_stat_config *config, struct perf_tool *tool,
+int perf_event__synthesize_stat_events(struct perf_stat_config *config, const struct perf_tool *tool,
 				       struct evlist *evlist, perf_event__handler_t process, bool attrs)
 {
 	int err;
···
 
 extern const struct perf_header_feature_ops feat_ops[HEADER_LAST_FEATURE];
 
-int perf_event__synthesize_features(struct perf_tool *tool, struct perf_session *session,
+int perf_event__synthesize_features(const struct perf_tool *tool, struct perf_session *session,
 				    struct evlist *evlist, perf_event__handler_t process)
 {
 	struct perf_header *header = &session->header;
···
 	return ret;
 }
 
-int perf_event__synthesize_for_pipe(struct perf_tool *tool,
+int perf_event__synthesize_for_pipe(const struct perf_tool *tool,
 				    struct perf_session *session,
 				    struct perf_data *data,
 				    perf_event__handler_t process)

tools/perf/util/synthetic-events.h

···
 
 int parse_synth_opt(char *str);
 
-typedef int (*perf_event__handler_t)(struct perf_tool *tool, union perf_event *event,
+typedef int (*perf_event__handler_t)(const struct perf_tool *tool, union perf_event *event,
 				     struct perf_sample *sample, struct machine *machine);
 
-int perf_event__synthesize_attrs(struct perf_tool *tool, struct evlist *evlist, perf_event__handler_t process);
-int perf_event__synthesize_attr(struct perf_tool *tool, struct perf_event_attr *attr, u32 ids, u64 *id, perf_event__handler_t process);
-int perf_event__synthesize_build_id(struct perf_tool *tool, struct dso *pos, u16 misc, perf_event__handler_t process, struct machine *machine);
-int perf_event__synthesize_cpu_map(struct perf_tool *tool, const struct perf_cpu_map *cpus, perf_event__handler_t process, struct machine *machine);
-int perf_event__synthesize_event_update_cpus(struct perf_tool *tool, struct evsel *evsel, perf_event__handler_t process);
-int perf_event__synthesize_event_update_name(struct perf_tool *tool, struct evsel *evsel, perf_event__handler_t process);
-int perf_event__synthesize_event_update_scale(struct perf_tool *tool, struct evsel *evsel, perf_event__handler_t process);
-int perf_event__synthesize_event_update_unit(struct perf_tool *tool, struct evsel *evsel, perf_event__handler_t process);
-int perf_event__synthesize_extra_attr(struct perf_tool *tool, struct evlist *evsel_list, perf_event__handler_t process, bool is_pipe);
-int perf_event__synthesize_extra_kmaps(struct perf_tool *tool, perf_event__handler_t process, struct machine *machine);
-int perf_event__synthesize_features(struct perf_tool *tool, struct perf_session *session, struct evlist *evlist, perf_event__handler_t process);
-int perf_event__synthesize_id_index(struct perf_tool *tool, perf_event__handler_t process, struct evlist *evlist, struct machine *machine);
-int __perf_event__synthesize_id_index(struct perf_tool *tool, perf_event__handler_t process, struct evlist *evlist, struct machine *machine, size_t from);
+int perf_event__synthesize_attrs(const struct perf_tool *tool, struct evlist *evlist, perf_event__handler_t process);
+int perf_event__synthesize_attr(const struct perf_tool *tool, struct perf_event_attr *attr, u32 ids, u64 *id, perf_event__handler_t process);
+int perf_event__synthesize_build_id(const struct perf_tool *tool, struct dso *pos, u16 misc, perf_event__handler_t process, struct machine *machine);
+int perf_event__synthesize_cpu_map(const struct perf_tool *tool, const struct perf_cpu_map *cpus, perf_event__handler_t process, struct machine *machine);
+int perf_event__synthesize_event_update_cpus(const struct perf_tool *tool, struct evsel *evsel, perf_event__handler_t process);
+int perf_event__synthesize_event_update_name(const struct perf_tool *tool, struct evsel *evsel, perf_event__handler_t process);
+int perf_event__synthesize_event_update_scale(const struct perf_tool *tool, struct evsel *evsel, perf_event__handler_t process);
+int perf_event__synthesize_event_update_unit(const struct perf_tool *tool, struct evsel *evsel, perf_event__handler_t process);
+int perf_event__synthesize_extra_attr(const struct perf_tool *tool, struct evlist *evsel_list, perf_event__handler_t process, bool is_pipe);
+int perf_event__synthesize_extra_kmaps(const struct perf_tool *tool, perf_event__handler_t process, struct machine *machine);
+int perf_event__synthesize_features(const struct perf_tool *tool, struct perf_session *session, struct evlist *evlist, perf_event__handler_t process);
+int perf_event__synthesize_id_index(const struct perf_tool *tool, perf_event__handler_t process, struct evlist *evlist, struct machine *machine);
+int __perf_event__synthesize_id_index(const struct perf_tool *tool, perf_event__handler_t process, struct evlist *evlist, struct machine *machine, size_t from);
 int perf_event__synthesize_id_sample(__u64 *array, u64 type, const struct perf_sample *sample);
-int perf_event__synthesize_kernel_mmap(struct perf_tool *tool, perf_event__handler_t process, struct machine *machine);
-int perf_event__synthesize_mmap_events(struct perf_tool *tool, union perf_event *event, pid_t pid, pid_t tgid, perf_event__handler_t process, struct machine *machine, bool mmap_data);
-int perf_event__synthesize_modules(struct perf_tool *tool, perf_event__handler_t process, struct machine *machine);
-int perf_event__synthesize_namespaces(struct perf_tool *tool, union perf_event *event, pid_t pid, pid_t tgid, perf_event__handler_t process, struct machine *machine);
-int perf_event__synthesize_cgroups(struct perf_tool *tool, perf_event__handler_t process, struct machine *machine);
+int perf_event__synthesize_kernel_mmap(const struct perf_tool *tool, perf_event__handler_t process, struct machine *machine);
+int perf_event__synthesize_mmap_events(const struct perf_tool *tool, union perf_event *event, pid_t pid, pid_t tgid, perf_event__handler_t process, struct machine *machine, bool mmap_data);
+int perf_event__synthesize_modules(const struct perf_tool *tool, perf_event__handler_t process, struct machine *machine);
+int perf_event__synthesize_namespaces(const struct perf_tool *tool, union perf_event *event, pid_t pid, pid_t tgid, perf_event__handler_t process, struct machine *machine);
+int perf_event__synthesize_cgroups(const struct perf_tool *tool, perf_event__handler_t process, struct machine *machine);
 int perf_event__synthesize_sample(union perf_event *event, u64 type, u64 read_format, const struct perf_sample *sample);
-int perf_event__synthesize_stat_config(struct perf_tool *tool, struct perf_stat_config *config, perf_event__handler_t process, struct machine *machine);
-int perf_event__synthesize_stat_events(struct perf_stat_config *config, struct perf_tool *tool, struct evlist *evlist, perf_event__handler_t process, bool attrs);
-int perf_event__synthesize_stat_round(struct perf_tool *tool, u64 time, u64 type, perf_event__handler_t process, struct machine *machine);
-int perf_event__synthesize_stat(struct perf_tool *tool, struct perf_cpu cpu, u32 thread, u64 id, struct perf_counts_values *count, perf_event__handler_t process, struct machine *machine);
-int perf_event__synthesize_thread_map2(struct perf_tool *tool, struct perf_thread_map *threads, perf_event__handler_t process, struct machine *machine);
-int perf_event__synthesize_thread_map(struct perf_tool *tool, struct perf_thread_map *threads, perf_event__handler_t process, struct machine *machine, bool needs_mmap, bool mmap_data);
-int perf_event__synthesize_threads(struct perf_tool *tool, perf_event__handler_t process, struct machine *machine, bool needs_mmap, bool mmap_data, unsigned int nr_threads_synthesize);
-int perf_event__synthesize_tracing_data(struct perf_tool *tool, int fd, struct evlist *evlist, perf_event__handler_t process);
-int perf_event__synth_time_conv(const struct perf_event_mmap_page *pc, struct perf_tool *tool, perf_event__handler_t process, struct machine *machine);
-pid_t perf_event__synthesize_comm(struct perf_tool *tool, union perf_event *event, pid_t pid, perf_event__handler_t process, struct machine *machine);
+int perf_event__synthesize_stat_config(const struct perf_tool *tool, struct perf_stat_config *config, perf_event__handler_t process, struct machine *machine);
+int perf_event__synthesize_stat_events(struct perf_stat_config *config, const struct perf_tool *tool, struct evlist *evlist, perf_event__handler_t process, bool attrs);
+int perf_event__synthesize_stat_round(const struct perf_tool *tool, u64 time, u64 type, perf_event__handler_t process, struct machine *machine);
+int perf_event__synthesize_stat(const struct perf_tool *tool, struct perf_cpu cpu, u32 thread, u64 id, struct perf_counts_values *count, perf_event__handler_t process, struct machine *machine);
+int perf_event__synthesize_thread_map2(const struct perf_tool *tool, struct perf_thread_map *threads, perf_event__handler_t process, struct machine *machine);
+int perf_event__synthesize_thread_map(const struct perf_tool *tool, struct perf_thread_map *threads, perf_event__handler_t process, struct machine *machine, bool needs_mmap, bool mmap_data);
+int perf_event__synthesize_threads(const struct perf_tool *tool, perf_event__handler_t process, struct machine *machine, bool needs_mmap, bool mmap_data, unsigned int nr_threads_synthesize);
+int perf_event__synthesize_tracing_data(const struct perf_tool *tool, int fd, struct evlist *evlist, perf_event__handler_t process);
+int perf_event__synth_time_conv(const struct perf_event_mmap_page *pc, const struct perf_tool *tool, perf_event__handler_t process, struct machine *machine);
+pid_t perf_event__synthesize_comm(const struct perf_tool *tool, union perf_event *event, pid_t pid, perf_event__handler_t process, struct machine *machine);
 
-int perf_tool__process_synth_event(struct perf_tool *tool, union perf_event *event, struct machine *machine, perf_event__handler_t process);
+int perf_tool__process_synth_event(const struct perf_tool *tool, union perf_event *event, struct machine *machine, perf_event__handler_t process);
 
 size_t perf_event__sample_event_size(const struct perf_sample *sample, u64 type, u64 read_format);
 
-int __machine__synthesize_threads(struct machine *machine, struct perf_tool *tool,
+int __machine__synthesize_threads(struct machine *machine, const struct perf_tool *tool,
 				  struct target *target, struct perf_thread_map *threads,
 				  perf_event__handler_t process, bool needs_mmap, bool data_mmap,
 				  unsigned int nr_threads_synthesize);
···
 				unsigned int nr_threads_synthesize);
 
 #ifdef HAVE_AUXTRACE_SUPPORT
-int perf_event__synthesize_auxtrace_info(struct auxtrace_record *itr, struct perf_tool *tool,
+int perf_event__synthesize_auxtrace_info(struct auxtrace_record *itr, const struct perf_tool *tool,
 					 struct perf_session *session, perf_event__handler_t process);
 
 #else // HAVE_AUXTRACE_SUPPORT
···
 
 static inline int
 perf_event__synthesize_auxtrace_info(struct auxtrace_record *itr __maybe_unused,
-				     struct perf_tool *tool __maybe_unused,
+				     const struct perf_tool *tool __maybe_unused,
 				     struct perf_session *session __maybe_unused,
 				     perf_event__handler_t process __maybe_unused)
 {
···
 }
 #endif // HAVE_LIBBPF_SUPPORT
 
-int perf_event__synthesize_for_pipe(struct perf_tool *tool,
+int perf_event__synthesize_for_pipe(const struct perf_tool *tool,
 				    struct perf_session *session,
 				    struct perf_data *data,
 				    perf_event__handler_t process);

tools/perf/util/tool.h

···
 struct machine;
 struct ordered_events;
 
-typedef int (*event_sample)(struct perf_tool *tool, union perf_event *event,
+typedef int (*event_sample)(const struct perf_tool *tool, union perf_event *event,
 			    struct perf_sample *sample,
 			    struct evsel *evsel, struct machine *machine);
 
-typedef int (*event_op)(struct perf_tool *tool, union perf_event *event,
+typedef int (*event_op)(const struct perf_tool *tool, union perf_event *event,
 			struct perf_sample *sample, struct machine *machine);
 
-typedef int (*event_attr_op)(struct perf_tool *tool,
+typedef int (*event_attr_op)(const struct perf_tool *tool,
 			     union perf_event *event,
 			     struct evlist **pevlist);
 
···
 typedef int (*event_op4)(struct perf_session *session, union perf_event *event, u64 data,
 			 const char *str);
 
-typedef int (*event_oe)(struct perf_tool *tool, union perf_event *event,
+typedef int (*event_oe)(const struct perf_tool *tool, union perf_event *event,
 			struct ordered_events *oe);
 
 enum show_feature_header {

tools/perf/util/tsc.c

···
 }
 
 int perf_event__synth_time_conv(const struct perf_event_mmap_page *pc,
-				struct perf_tool *tool,
+				const struct perf_tool *tool,
 				perf_event__handler_t process,
 				struct machine *machine)
 {