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>

49 files changed, 314 insertions, 316 deletions

diff --git a/tools/perf/arch/x86/util/event.c b/tools/perf/arch/x86/util/event.c
index e65b7dbe27fb..a0400707180c 100644
--- a/tools/perf/arch/x86/util/event.c
+++ b/tools/perf/arch/x86/util/event.c
@@ -15,7 +15,7 @@
 #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;
@@ -65,7 +65,7 @@ static int perf_event__synthesize_extra_kmaps_cb(struct map *map, void *data)
 	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)
 {
diff --git a/tools/perf/bench/synthesize.c b/tools/perf/bench/synthesize.c
index 7401ebbac100..9b333276cbdb 100644
--- a/tools/perf/bench/synthesize.c
+++ b/tools/perf/bench/synthesize.c
@@ -49,7 +49,7 @@ static const char *const bench_usage[] = {
 
 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)
diff --git a/tools/perf/builtin-annotate.c b/tools/perf/builtin-annotate.c
index 1bfe41783a7c..cc65e6f8f4da 100644
--- a/tools/perf/builtin-annotate.c
+++ b/tools/perf/builtin-annotate.c
@@ -279,7 +279,7 @@ static int evsel__add_sample(struct evsel *evsel, struct perf_sample *sample,
 	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,
diff --git a/tools/perf/builtin-c2c.c b/tools/perf/builtin-c2c.c
index c157bd31f2e5..88c131d05186 100644
--- a/tools/perf/builtin-c2c.c
+++ b/tools/perf/builtin-c2c.c
@@ -273,7 +273,7 @@ static void compute_stats(struct c2c_hist_entry *c2c_he,
 		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,
diff --git a/tools/perf/builtin-diff.c b/tools/perf/builtin-diff.c
index 57d300d8e570..4c0567882a7a 100644
--- a/tools/perf/builtin-diff.c
+++ b/tools/perf/builtin-diff.c
@@ -388,7 +388,7 @@ struct hist_entry_ops block_hist_ops = {
 	.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,
diff --git a/tools/perf/builtin-inject.c b/tools/perf/builtin-inject.c
index 8f3dd8980da0..283429ccd034 100644
--- a/tools/perf/builtin-inject.c
+++ b/tools/perf/builtin-inject.c
@@ -134,7 +134,7 @@ struct event_entry {
 	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)
@@ -149,7 +149,7 @@ 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,
@@ -158,7 +158,7 @@ static int perf_event__repipe_synth(struct perf_tool *tool,
 	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)
 {
@@ -166,7 +166,7 @@ static int perf_event__repipe_oe_synth(struct perf_tool *tool,
 }
 
 #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)
 {
@@ -188,7 +188,7 @@ static int perf_event__repipe_op4_synth(struct perf_session *session,
 	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)
 {
@@ -206,7 +206,7 @@ static int perf_event__repipe_attr(struct perf_tool *tool,
 	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)
 {
@@ -237,7 +237,7 @@ static int copy_bytes(struct perf_inject *inject, struct perf_data *data, off_t
 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;
@@ -284,7 +284,7 @@ perf_event__repipe_auxtrace(struct perf_session *session __maybe_unused,
 
 #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)
@@ -292,7 +292,7 @@ static int perf_event__repipe(struct perf_tool *tool,
 	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)
@@ -300,7 +300,7 @@ static int perf_event__drop(struct perf_tool *tool __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)
@@ -341,13 +341,13 @@ perf_inject__cut_auxtrace_sample(struct perf_inject *inject,
 	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,
@@ -372,7 +372,7 @@ static int perf_event__repipe_sample(struct perf_tool *tool,
 	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)
@@ -386,7 +386,7 @@ static int perf_event__repipe_mmap(struct perf_tool *tool,
 }
 
 #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)
@@ -455,7 +455,7 @@ static struct dso *findnew_dso(int pid, int tid, const char *filename,
 	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)
@@ -474,7 +474,7 @@ static int perf_event__repipe_buildid_mmap(struct perf_tool *tool,
 	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)
@@ -500,7 +500,7 @@ static int perf_event__repipe_mmap2(struct perf_tool *tool,
 }
 
 #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)
@@ -524,7 +524,7 @@ static int perf_event__jit_repipe_mmap2(struct perf_tool *tool,
 }
 #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)
@@ -565,7 +565,7 @@ static int perf_event__repipe_buildid_mmap2(struct perf_tool *tool,
 	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)
@@ -578,7 +578,7 @@ static int perf_event__repipe_fork(struct perf_tool *tool,
 	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)
@@ -591,7 +591,7 @@ static int perf_event__repipe_comm(struct perf_tool *tool,
 	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)
@@ -603,7 +603,7 @@ static int perf_event__repipe_namespaces(struct perf_tool *tool,
 	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)
@@ -712,7 +712,7 @@ static bool perf_inject__lookup_known_build_id(struct perf_inject *inject,
 	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,
@@ -743,7 +743,7 @@ static int dso__inject_build_id(struct dso *dso, struct perf_tool *tool,
 	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)
@@ -776,7 +776,7 @@ repipe:
 	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,
@@ -796,7 +796,7 @@ static int perf_inject__sched_process_exit(struct perf_tool *tool,
 	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,
@@ -821,7 +821,7 @@ static int perf_inject__sched_switch(struct perf_tool *tool,
 }
 
 #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,
@@ -866,7 +866,7 @@ static int guest_session__output_bytes(struct guest_session *gs, void *buf, size
 	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)
@@ -1032,7 +1032,7 @@ static struct guest_id *guest_session__lookup_id(struct guest_session *gs, u64 i
 	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)
 {
@@ -1160,7 +1160,7 @@ static u64 evlist__first_id(struct evlist *evlist)
 	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)
@@ -1210,7 +1210,7 @@ static int guest_session__add_build_ids(struct guest_session *gs)
 				  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)
@@ -1574,7 +1574,7 @@ static int guest_session__flush_events(struct guest_session *gs)
 	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)
@@ -1647,7 +1647,7 @@ static int host__finished_init(struct perf_session *session, union perf_event *e
  * 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)
 {
@@ -1665,7 +1665,7 @@ static int host__finished_round(struct perf_tool *tool,
 	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)
@@ -1719,7 +1719,7 @@ static int evsel__check_stype(struct evsel *evsel, u64 sample_type, const char *
 	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,
diff --git a/tools/perf/builtin-kmem.c b/tools/perf/builtin-kmem.c
index 6fd95be5032b..859ff018eace 100644
--- a/tools/perf/builtin-kmem.c
+++ b/tools/perf/builtin-kmem.c
@@ -955,7 +955,7 @@ static bool perf_kmem__skip_sample(struct perf_sample *sample)
 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,
@@ -2061,4 +2061,3 @@ out_delete:
 
 	return ret;
 }
-
diff --git a/tools/perf/builtin-kvm.c b/tools/perf/builtin-kvm.c
index 71165036e4ca..a3b903cf4311 100644
--- a/tools/perf/builtin-kvm.c
+++ b/tools/perf/builtin-kvm.c
@@ -1166,7 +1166,7 @@ static void print_result(struct perf_kvm_stat *kvm)
 }
 
 #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)
@@ -1187,7 +1187,7 @@ static bool skip_sample(struct perf_kvm_stat *kvm,
 	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,
diff --git a/tools/perf/builtin-kwork.c b/tools/perf/builtin-kwork.c
index 56e3f3a5e03a..8ffaa80a2d1d 100644
--- a/tools/perf/builtin-kwork.c
+++ b/tools/perf/builtin-kwork.c
@@ -958,7 +958,7 @@ static int top_sched_switch_event(struct perf_kwork *kwork,
 }
 
 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)
@@ -971,7 +971,7 @@ static int process_irq_handler_entry_event(struct perf_tool *tool,
 	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)
@@ -1037,7 +1037,7 @@ static struct kwork_class kwork_irq = {
 };
 
 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)
@@ -1051,7 +1051,7 @@ static int process_softirq_raise_event(struct perf_tool *tool,
 	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)
@@ -1065,7 +1065,7 @@ static int process_softirq_entry_event(struct perf_tool *tool,
 	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)
@@ -1167,7 +1167,7 @@ static struct kwork_class kwork_softirq = {
 };
 
 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)
@@ -1181,7 +1181,7 @@ static int process_workqueue_activate_work_event(struct perf_tool *tool,
 	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)
@@ -1195,7 +1195,7 @@ static int process_workqueue_execute_start_event(struct perf_tool *tool,
 	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)
@@ -1266,7 +1266,7 @@ static struct kwork_class kwork_workqueue = {
 };
 
 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)
@@ -1945,12 +1945,12 @@ static int perf_kwork__report(struct perf_kwork *kwork)
 	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,
diff --git a/tools/perf/builtin-lock.c b/tools/perf/builtin-lock.c
index 0253184b3b58..6efa9d646637 100644
--- a/tools/perf/builtin-lock.c
+++ b/tools/perf/builtin-lock.c
@@ -1501,7 +1501,7 @@ static const struct evsel_str_handler contention_tracepoints[] = {
 	{ "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)
 {
@@ -1520,7 +1520,7 @@ static int process_event_update(struct perf_tool *tool,
 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,
diff --git a/tools/perf/builtin-mem.c b/tools/perf/builtin-mem.c
index efa700d14c98..0fb4d75ab959 100644
--- a/tools/perf/builtin-mem.c
+++ b/tools/perf/builtin-mem.c
@@ -179,7 +179,7 @@ out:
 }
 
 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)</