[PATCH 16/25] perf tools: Synthesize build id for kernel/modules/tasks

Jiri Olsa
2020-11-26T17:01:53Z

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

Signed-off-by: Jiri Olsa <jolsa@kernel.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