linux-kernel - [PATCH 15/24] perf tools: Synthesize build id for kernel/modules/tasks

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Message-Id: <20201117110053.1303113-16-jolsa@kernel.org>
Date:   Tue, 17 Nov 2020 12:00:44 +0100
From:   Jiri Olsa <jolsa@...nel.org>
To:     Arnaldo Carvalho de Melo <acme@...nel.org>
Cc:     lkml <linux-kernel@...r.kernel.org>,
        Peter Zijlstra <a.p.zijlstra@...llo.nl>,
        Ingo Molnar <mingo@...nel.org>,
        Mark Rutland <mark.rutland@....com>,
        Namhyung Kim <namhyung@...nel.org>,
        Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
        Michael Petlan <mpetlan@...hat.com>,
        Song Liu <songliubraving@...com>,
        Ian Rogers <irogers@...gle.com>,
        Stephane Eranian <eranian@...gle.com>,
        Alexey Budankov <alexey.budankov@...ux.intel.com>,
        Andi Kleen <ak@...ux.intel.com>,
        Adrian Hunter <adrian.hunter@...el.com>
Subject: [PATCH 15/24] perf tools: Synthesize build id for kernel/modules/tasks

Adding build id to synthesized mmap2 events for
everything - kernel/modules/tasks.

Signed-off-by: Jiri Olsa <jolsa@...nel.org>
---
 tools/perf/util/synthetic-events.c | 32 ++++++++++++++++++++++++++++++
 1 file changed, 32 insertions(+)

diff --git a/tools/perf/util/synthetic-events.c b/tools/perf/util/synthetic-events.c
index a18ae502d765..91b1962d399c 100644
--- a/tools/perf/util/synthetic-events.c
+++ b/tools/perf/util/synthetic-events.c
@@ -347,6 +347,31 @@ static bool read_proc_maps_line(struct io *io, __u64 *start, __u64 *end,
 	}
 }
 
+static void perf_record_mmap2__read_build_id(struct perf_record_mmap2 *event,
+					     bool is_kernel)
+{
+	struct build_id bid;
+	int rc;
+
+	if (is_kernel)
+		rc = sysfs__read_build_id("/sys/kernel/notes", &bid);
+	else
+		rc = filename__read_build_id(event->filename, &bid) > 0 ? 0 : -1;
+
+	if (rc == 0) {
+		memcpy(event->build_id, bid.data, sizeof(bid.data));
+		event->build_id_size = (u8) bid.size;
+		event->header.misc |= PERF_RECORD_MISC_MMAP_BUILD_ID;
+		event->__reserved_1 = 0;
+		event->__reserved_2 = 0;
+	} else {
+		if (event->filename[0] == '/') {
+			pr_debug2("Failed to read build ID for %s\n",
+				  event->filename);
+		}
+	}
+}
+
 int perf_event__synthesize_mmap_events(struct perf_tool *tool,
 				       union perf_event *event,
 				       pid_t pid, pid_t tgid,
@@ -453,6 +478,9 @@ int perf_event__synthesize_mmap_events(struct perf_tool *tool,
 		event->mmap2.pid = tgid;
 		event->mmap2.tid = pid;
 
+		if (symbol_conf.buildid_mmap2)
+			perf_record_mmap2__read_build_id(&event->mmap2, false);
+
 		if (perf_tool__process_synth_event(tool, event, machine, process) != 0) {
 			rc = -1;
 			break;
@@ -630,6 +658,8 @@ int perf_event__synthesize_modules(struct perf_tool *tool, perf_event__handler_t
 
 			memcpy(event->mmap2.filename, pos->dso->long_name,
 			       pos->dso->long_name_len + 1);
+
+			perf_record_mmap2__read_build_id(&event->mmap2, false);
 		} else {
 			size = PERF_ALIGN(pos->dso->long_name_len + 1, sizeof(u64));
 			event->mmap.header.type = PERF_RECORD_MMAP;
@@ -1050,6 +1080,8 @@ static int __perf_event__synthesize_kernel_mmap(struct perf_tool *tool,
 		event->mmap2.start = map->start;
 		event->mmap2.len   = map->end - event->mmap.start;
 		event->mmap2.pid   = machine->pid;
+
+		perf_record_mmap2__read_build_id(&event->mmap2, true);
 	} else {
 		size = snprintf(event->mmap.filename, sizeof(event->mmap.filename),
 				"%s%s", machine->mmap_name, kmap->ref_reloc_sym->name) + 1;
-- 
2.26.2