Message-ID: <20250605233934.1881839-4-blakejones@google.com>
Date: Thu,  5 Jun 2025 16:39:33 -0700
From: Blake Jones <blakejones@...gle.com>
To: Arnaldo Carvalho de Melo <acme@...nel.org>, Namhyung Kim <namhyung@...nel.org>, 
	Ian Rogers <irogers@...gle.com>, Jiri Olsa <jolsa@...nel.org>, 
	Peter Zijlstra <peterz@...radead.org>, Ingo Molnar <mingo@...hat.com>
Cc: Mark Rutland <mark.rutland@....com>, 
	Alexander Shishkin <alexander.shishkin@...ux.intel.com>, 
	Adrian Hunter <adrian.hunter@...el.com>, Kan Liang <kan.liang@...ux.intel.com>, 
	Steven Rostedt <rostedt@...dmis.org>, Tomas Glozar <tglozar@...hat.com>, 
	James Clark <james.clark@...aro.org>, Leo Yan <leo.yan@....com>, 
	Guilherme Amadio <amadio@...too.org>, Yang Jihong <yangjihong@...edance.com>, 
	Charlie Jenkins <charlie@...osinc.com>, Chun-Tse Shao <ctshao@...gle.com>, 
	Aditya Gupta <adityag@...ux.ibm.com>, Athira Rajeev <atrajeev@...ux.vnet.ibm.com>, 
	Zhongqiu Han <quic_zhonhan@...cinc.com>, Andi Kleen <ak@...ux.intel.com>, 
	Dmitry Vyukov <dvyukov@...gle.com>, Yujie Liu <yujie.liu@...el.com>, 
	Graham Woodward <graham.woodward@....com>, Yicong Yang <yangyicong@...ilicon.com>, 
	Ben Gainey <ben.gainey@....com>, linux-kernel@...r.kernel.org, 
	linux-perf-users@...r.kernel.org, bpf@...r.kernel.org, 
	Blake Jones <blakejones@...gle.com>
Subject: [PATCH v2 3/4] perf: collect BPF metadata from new programs, and
 display the new event

This collects metadata for any BPF programs that were loaded during a
"perf record" run, and emits it at the end of the run. It also adds support
for displaying the new PERF_RECORD_BPF_METADATA type.

Here's some example "perf script -D" output for the new event type. The
": unhandled!" message is from tool.c, analogous to other behavior there.
I've elided some rows with all NUL characters for brevity, and I wrapped
one of the >75-column lines to fit in the commit guidelines.

0x50fc8@...f.data [0x260]: event: 84
.
. ... raw event: size 608 bytes
.  0000:  54 00 00 00 00 00 60 02 62 70 66 5f 70 72 6f 67  T.....`.bpf_prog
.  0010:  5f 31 65 30 61 32 65 33 36 36 65 35 36 66 31 61  _1e0a2e366e56f1a
.  0020:  32 5f 70 65 72 66 5f 73 61 6d 70 6c 65 5f 66 69  2_perf_sample_fi
.  0030:  6c 74 65 72 00 00 00 00 00 00 00 00 00 00 00 00  lter............
.  0040:  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
[...]
.  0110:  74 65 73 74 5f 76 61 6c 75 65 00 00 00 00 00 00  test_value......
.  0120:  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
[...]
.  0150:  34 32 00 00 00 00 00 00 00 00 00 00 00 00 00 00  42..............
.  0160:  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
[...]

0 0x50fc8 [0x260]: PERF_RECORD_BPF_METADATA \
      prog bpf_prog_1e0a2e366e56f1a2_perf_sample_filter
  entry 0:           test_value = 42
: unhandled!

Signed-off-by: Blake Jones <blakejones@...gle.com>
---
 tools/perf/builtin-inject.c        |  1 +
 tools/perf/builtin-record.c        |  8 ++++++
 tools/perf/builtin-script.c        | 15 ++++++++--
 tools/perf/util/bpf-event.c        | 46 ++++++++++++++++++++++++++++++
 tools/perf/util/bpf-event.h        |  1 +
 tools/perf/util/env.c              | 19 +++++++++++-
 tools/perf/util/env.h              |  4 +++
 tools/perf/util/event.c            | 21 ++++++++++++++
 tools/perf/util/event.h            |  1 +
 tools/perf/util/header.c           |  1 +
 tools/perf/util/session.c          |  4 +++
 tools/perf/util/synthetic-events.h |  2 ++
 tools/perf/util/tool.c             | 14 +++++++++
 tools/perf/util/tool.h             |  3 +-
 14 files changed, 136 insertions(+), 4 deletions(-)

diff --git a/tools/perf/builtin-inject.c b/tools/perf/builtin-inject.c
index 11e49cafa3af..b15eac0716f7 100644
--- a/tools/perf/builtin-inject.c
+++ b/tools/perf/builtin-inject.c
@@ -2530,6 +2530,7 @@ int cmd_inject(int argc, const char **argv)
 	inject.tool.finished_init	= perf_event__repipe_op2_synth;
 	inject.tool.compressed		= perf_event__repipe_op4_synth;
 	inject.tool.auxtrace		= perf_event__repipe_auxtrace;
+	inject.tool.bpf_metadata	= perf_event__repipe_op2_synth;
 	inject.tool.dont_split_sample_group = true;
 	inject.session = __perf_session__new(&data, &inject.tool,
 					     /*trace_event_repipe=*/inject.output.is_pipe);
diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
index 136c0172799a..067e203f57c2 100644
--- a/tools/perf/builtin-record.c
+++ b/tools/perf/builtin-record.c
@@ -2161,6 +2161,12 @@ static int record__synthesize(struct record *rec, bool tail)
 	return err;
 }
 
+static void record__synthesize_final_bpf_metadata(struct record *rec)
+{
+	perf_event__synthesize_final_bpf_metadata(rec->session,
+						  process_synthesized_event);
+}
+
 static int record__process_signal_event(union perf_event *event __maybe_unused, void *data)
 {
 	struct record *rec = data;
@@ -2806,6 +2812,8 @@ static int __cmd_record(struct record *rec, int argc, const char **argv)
 	trigger_off(&auxtrace_snapshot_trigger);
 	trigger_off(&switch_output_trigger);
 
+	record__synthesize_final_bpf_metadata(rec);
+
 	if (opts->auxtrace_snapshot_on_exit)
 		record__auxtrace_snapshot_exit(rec);
 
diff --git a/tools/perf/builtin-script.c b/tools/perf/builtin-script.c
index 6c3bf74dd78c..4001e621b6cb 100644
--- a/tools/perf/builtin-script.c
+++ b/tools/perf/builtin-script.c
@@ -38,6 +38,7 @@
 #include "print_insn.h"
 #include "archinsn.h"
 #include <linux/bitmap.h>
+#include <linux/compiler.h>
 #include <linux/kernel.h>
 #include <linux/stringify.h>
 #include <linux/time64.h>
@@ -50,6 +51,7 @@
 #include <errno.h>
 #include <inttypes.h>
 #include <signal.h>
+#include <stdio.h>
 #include <sys/param.h>
 #include <sys/types.h>
 #include <sys/stat.h>
@@ -2755,6 +2757,14 @@ process_bpf_events(const struct perf_tool *tool __maybe_unused,
 			   sample->tid);
 }
 
+static int
+process_bpf_metadata_event(struct perf_session *session __maybe_unused,
+			   union perf_event *event)
+{
+	perf_event__fprintf(event, NULL, stdout);
+	return 0;
+}
+
 static int process_text_poke_events(const struct perf_tool *tool,
 				    union perf_event *event,
 				    struct perf_sample *sample,
@@ -2877,8 +2887,9 @@ static int __cmd_script(struct perf_script *script)
 		script->tool.finished_round = process_finished_round_event;
 	}
 	if (script->show_bpf_events) {
-		script->tool.ksymbol = process_bpf_events;
-		script->tool.bpf     = process_bpf_events;
+		script->tool.ksymbol	  = process_bpf_events;
+		script->tool.bpf	  = process_bpf_events;
+		script->tool.bpf_metadata = process_bpf_metadata_event;
 	}
 	if (script->show_text_poke_events) {
 		script->tool.ksymbol   = process_bpf_events;
diff --git a/tools/perf/util/bpf-event.c b/tools/perf/util/bpf-event.c
index 1f6e76ee6024..dc09a4730c50 100644
--- a/tools/perf/util/bpf-event.c
+++ b/tools/perf/util/bpf-event.c
@@ -472,6 +472,49 @@ void bpf_metadata_free(struct bpf_metadata *metadata __maybe_unused)
 
 #endif /* HAVE_LIBBPF_STRINGS_SUPPORT */
 
+struct bpf_metadata_final_ctx {
+	const struct perf_tool *tool;
+	perf_event__handler_t process;
+	struct machine *machine;
+};
+
+static void synthesize_final_bpf_metadata_cb(struct bpf_prog_info_node *node,
+					     void *data)
+{
+	struct bpf_metadata_final_ctx *ctx = (struct bpf_metadata_final_ctx *)data;
+	struct bpf_metadata *metadata = node->metadata;
+	int err;
+
+	if (metadata == NULL)
+		return;
+	err = synthesize_perf_record_bpf_metadata(metadata, ctx->tool,
+						  ctx->process, ctx->machine);
+	if (err != 0) {
+		const char *prog_name = metadata->prog_names[0];
+
+		if (prog_name != NULL)
+			pr_warning("Couldn't synthesize final BPF metadata for %s.\n", prog_name);
+		else
+			pr_warning("Couldn't synthesize final BPF metadata.\n");
+	}
+	bpf_metadata_free(metadata);
+	node->metadata = NULL;
+}
+
+void perf_event__synthesize_final_bpf_metadata(struct perf_session *session,
+					       perf_event__handler_t process)
+{
+	struct perf_env *env = &session->header.env;
+	struct bpf_metadata_final_ctx ctx = {
+		.tool = session->tool,
+		.process = process,
+		.machine = &session->machines.host,
+	};
+
+	perf_env__iterate_bpf_prog_info(env, synthesize_final_bpf_metadata_cb,
+					&ctx);
+}
+
 /*
  * Synthesize PERF_RECORD_KSYMBOL and PERF_RECORD_BPF_EVENT for one bpf
  * program. One PERF_RECORD_BPF_EVENT is generated for the program. And
@@ -612,6 +655,7 @@ static int perf_event__synthesize_one_bpf_prog(struct perf_session *session,
 		}
 
 		info_node->info_linear = info_linear;
+		info_node->metadata = NULL;
 		if (!perf_env__insert_bpf_prog_info(env, info_node)) {
 			free(info_linear);
 			free(info_node);
@@ -803,6 +847,7 @@ static void perf_env__add_bpf_info(struct perf_env *env, u32 id)
 	arrays |= 1UL << PERF_BPIL_JITED_INSNS;
 	arrays |= 1UL << PERF_BPIL_LINE_INFO;
 	arrays |= 1UL << PERF_BPIL_JITED_LINE_INFO;
+	arrays |= 1UL << PERF_BPIL_MAP_IDS;
 
 	info_linear = get_bpf_prog_info_linear(fd, arrays);
 	if (IS_ERR_OR_NULL(info_linear)) {
@@ -815,6 +860,7 @@ static void perf_env__add_bpf_info(struct perf_env *env, u32 id)
 	info_node = malloc(sizeof(struct bpf_prog_info_node));
 	if (info_node) {
 		info_node->info_linear = info_linear;
+		info_node->metadata = bpf_metadata_create(&info_linear->info);
 		if (!perf_env__insert_bpf_prog_info(env, info_node)) {
 			free(info_linear);
 			free(info_node);
diff --git a/tools/perf/util/bpf-event.h b/tools/perf/util/bpf-event.h
index 16644b3aaba1..1ed0b36dc3b8 100644
--- a/tools/perf/util/bpf-event.h
+++ b/tools/perf/util/bpf-event.h
@@ -25,6 +25,7 @@ struct bpf_metadata {
 
 struct bpf_prog_info_node {
 	struct perf_bpil		*info_linear;
+	struct bpf_metadata		*metadata;
 	struct rb_node			rb_node;
 };
 
diff --git a/tools/perf/util/env.c b/tools/perf/util/env.c
index 36411749e007..05a4f2657d72 100644
--- a/tools/perf/util/env.c
+++ b/tools/perf/util/env.c
@@ -3,8 +3,10 @@
 #include "debug.h"
 #include "env.h"
 #include "util/header.h"
-#include "linux/compiler.h"
+#include "util/rwsem.h"
+#include <linux/compiler.h>
 #include <linux/ctype.h>
+#include <linux/rbtree.h>
 #include <linux/string.h>
 #include <linux/zalloc.h>
 #include "cgroup.h"
@@ -89,6 +91,20 @@ struct bpf_prog_info_node *perf_env__find_bpf_prog_info(struct perf_env *env,
 	return node;
 }
 
+void perf_env__iterate_bpf_prog_info(struct perf_env *env,
+				     void (*cb)(struct bpf_prog_info_node *node,
+						void *data),
+				     void *data)
+{
+	struct rb_node *first;
+
+	down_read(&env->bpf_progs.lock);
+	first = rb_first(&env->bpf_progs.infos);
+	for (struct rb_node *node = first; node != NULL; node = rb_next(node))
+		(*cb)(rb_entry(node, struct bpf_prog_info_node, rb_node), data);
+	up_read(&env->bpf_progs.lock);
+}
+
 bool perf_env__insert_btf(struct perf_env *env, struct btf_node *btf_node)
 {
 	bool ret;
@@ -174,6 +190,7 @@ static void perf_env__purge_bpf(struct perf_env *env)
 		next = rb_next(&node->rb_node);
 		rb_erase(&node->rb_node, root);
 		zfree(&node->info_linear);
+		bpf_metadata_free(node->metadata);
 		free(node);
 	}
 
diff --git a/tools/perf/util/env.h b/tools/perf/util/env.h
index d90e343cf1fa..6819cb9b99ff 100644
--- a/tools/perf/util/env.h
+++ b/tools/perf/util/env.h
@@ -180,6 +180,10 @@ bool perf_env__insert_bpf_prog_info(struct perf_env *env,
 				    struct bpf_prog_info_node *info_node);
 struct bpf_prog_info_node *perf_env__find_bpf_prog_info(struct perf_env *env,
 							__u32 prog_id);
+void perf_env__iterate_bpf_prog_info(struct perf_env *env,
+				     void (*cb)(struct bpf_prog_info_node *node,
+						void *data),
+				     void *data);
 bool perf_env__insert_btf(struct perf_env *env, struct btf_node *btf_node);
 bool __perf_env__insert_btf(struct perf_env *env, struct btf_node *btf_node);
 struct btf_node *perf_env__find_btf(struct perf_env *env, __u32 btf_id);
diff --git a/tools/perf/util/event.c b/tools/perf/util/event.c
index 80c9ea682413..e81c2d87d76a 100644
--- a/tools/perf/util/event.c
+++ b/tools/perf/util/event.c
@@ -1,9 +1,12 @@
 #include <errno.h>
 #include <fcntl.h>
 #include <inttypes.h>
+#include <linux/compiler.h>
 #include <linux/kernel.h>
 #include <linux/types.h>
 #include <perf/cpumap.h>
+#include <perf/event.h>
+#include <stdio.h>
 #include <sys/types.h>
 #include <sys/stat.h>
 #include <unistd.h>
@@ -78,6 +81,7 @@ static const char *perf_event__names[] = {
 	[PERF_RECORD_COMPRESSED]		= "COMPRESSED",
 	[PERF_RECORD_FINISHED_INIT]		= "FINISHED_INIT",
 	[PERF_RECORD_COMPRESSED2]		= "COMPRESSED2",
+	[PERF_RECORD_BPF_METADATA]		= "BPF_METADATA",
 };
 
 const char *perf_event__name(unsigned int id)
@@ -504,6 +508,20 @@ size_t perf_event__fprintf_bpf(union perf_event *event, FILE *fp)
 		       event->bpf.type, event->bpf.flags, event->bpf.id);
 }
 
+size_t perf_event__fprintf_bpf_metadata(union perf_event *event, FILE *fp)
+{
+	struct perf_record_bpf_metadata *metadata = &event->bpf_metadata;
+	size_t ret;
+
+	ret = fprintf(fp, " prog %s\n", metadata->prog_name);
+	for (__u32 i = 0; i < metadata->nr_entries; i++) {
+		ret += fprintf(fp, "  entry %d: %20s = %s\n", i,
+			       metadata->entries[i].key,
+			       metadata->entries[i].value);
+	}
+	return ret;
+}
+
 static int text_poke_printer(enum binary_printer_ops op, unsigned int val,
 			     void *extra, FILE *fp)
 {
@@ -601,6 +619,9 @@ size_t perf_event__fprintf(union perf_event *event, struct machine *machine, FIL
 	case PERF_RECORD_AUX_OUTPUT_HW_ID:
 		ret += perf_event__fprintf_aux_output_hw_id(event, fp);
 		break;
+	case PERF_RECORD_BPF_METADATA:
+		ret += perf_event__fprintf_bpf_metadata(event, fp);
+		break;
 	default:
 		ret += fprintf(fp, "\n");
 	}
diff --git a/tools/perf/util/event.h b/tools/perf/util/event.h
index 664bf39567ce..67ad4a2014bc 100644
--- a/tools/perf/util/event.h
+++ b/tools/perf/util/event.h
@@ -370,6 +370,7 @@ size_t perf_event__fprintf_namespaces(union perf_event *event, FILE *fp);
 size_t perf_event__fprintf_cgroup(union perf_event *event, FILE *fp);
 size_t perf_event__fprintf_ksymbol(union perf_event *event, FILE *fp);
 size_t perf_event__fprintf_bpf(union perf_event *event, FILE *fp);
+size_t perf_event__fprintf_bpf_metadata(union perf_event *event, FILE *fp);
 size_t perf_event__fprintf_text_poke(union perf_event *event, struct machine *machine,FILE *fp);
 size_t perf_event__fprintf(union perf_event *event, struct machine *machine, FILE *fp);
 
diff --git a/tools/perf/util/header.c b/tools/perf/util/header.c
index e3cdc3b7b4ab..7c477e2a93b3 100644
--- a/tools/perf/util/header.c
+++ b/tools/perf/util/header.c
@@ -3161,6 +3161,7 @@ static int process_bpf_prog_info(struct feat_fd *ff, void *data __maybe_unused)
 		/* after reading from file, translate offset to address */
 		bpil_offs_to_addr(info_linear);
 		info_node->info_linear = info_linear;
+		info_node->metadata = NULL;
 		if (!__perf_env__insert_bpf_prog_info(env, info_node)) {
 			free(info_linear);
 			free(info_node);
diff --git a/tools/perf/util/session.c b/tools/perf/util/session.c
index a320672c264e..38075059086c 100644
--- a/tools/perf/util/session.c
+++ b/tools/perf/util/session.c
@@ -12,6 +12,7 @@
 #include <sys/types.h>
 #include <sys/mman.h>
 #include <perf/cpumap.h>
+#include <perf/event.h>
 
 #include "map_symbol.h"
 #include "branch.h"
@@ -1491,6 +1492,9 @@ static s64 perf_session__process_user_event(struct perf_session *session,
 	case PERF_RECORD_FINISHED_INIT:
 		err = tool->finished_init(session, event);
 		break;
+	case PERF_RECORD_BPF_METADATA:
+		err = tool->bpf_metadata(session, event);
+		break;
 	default:
 		err = -EINVAL;
 		break;
diff --git a/tools/perf/util/synthetic-events.h b/tools/perf/util/synthetic-events.h
index b9c936b5cfeb..ee29615d68e5 100644
--- a/tools/perf/util/synthetic-events.h
+++ b/tools/perf/util/synthetic-events.h
@@ -92,6 +92,8 @@ int perf_event__synthesize_threads(const struct perf_tool *tool, perf_event__han
 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);
+void perf_event__synthesize_final_bpf_metadata(struct perf_session *session,
+					       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);
 
diff --git a/tools/perf/util/tool.c b/tools/perf/util/tool.c
index 37bd8ac63b01..204ec03071bc 100644
--- a/tools/perf/util/tool.c
+++ b/tools/perf/util/tool.c
@@ -1,12 +1,15 @@
 // SPDX-License-Identifier: GPL-2.0
 #include "data.h"
 #include "debug.h"
+#include "event.h"
 #include "header.h"
 #include "session.h"
 #include "stat.h"
 #include "tool.h"
 #include "tsc.h"
+#include <linux/compiler.h>
 #include <sys/mman.h>
+#include <stddef.h>
 #include <unistd.h>
 
 #ifdef HAVE_ZSTD_SUPPORT
@@ -237,6 +240,16 @@ static int perf_session__process_compressed_event_stub(struct perf_session *sess
 	return 0;
 }
 
+static int perf_event__process_bpf_metadata_stub(struct perf_session *perf_session __maybe_unused,
+						 union perf_event *event)
+{
+	if (dump_trace)
+		perf_event__fprintf_bpf_metadata(event, stdout);
+
+	dump_printf(": unhandled!\n");
+	return 0;
+}
+
 void perf_tool__init(struct perf_tool *tool, bool ordered_events)
 {
 	tool->ordered_events = ordered_events;
@@ -293,6 +306,7 @@ void perf_tool__init(struct perf_tool *tool, bool ordered_events)
 	tool->compressed = perf_session__process_compressed_event_stub;
 #endif
 	tool->finished_init = process_event_op2_stub;
+	tool->bpf_metadata = perf_event__process_bpf_metadata_stub;
 }
 
 bool perf_tool__compressed_is_stub(const struct perf_tool *tool)
diff --git a/tools/perf/util/tool.h b/tools/perf/util/tool.h
index db1c7642b0d1..18b76ff0f26a 100644
--- a/tools/perf/util/tool.h
+++ b/tools/perf/util/tool.h
@@ -77,7 +77,8 @@ struct perf_tool {
 			stat,
 			stat_round,
 			feature,
-			finished_init;
+			finished_init,
+			bpf_metadata;
 	event_op4	compressed;
 	event_op3	auxtrace;
 	bool		ordered_events;
-- 
2.50.0.rc0.604.gd4ff7b7c86-goog

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