[PATCH 17/26] perf tools: Synthesize kernel with mmap3

Jiri Olsa
2020-09-13T21:05:28Z

Synthesizing kernel with mmap3 events so we can
get build id data for kernel map as well.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
---
tools/perf/util/synthetic-events.c | 23 ++++++++++++++---------
1 file changed, 14 insertions(+), 9 deletions(-)

diff --git a/tools/perf/util/synthetic-events.c b/tools/perf/util/synthetic-events.c
index 6bd2423ce2f3..844ca87b6e97 100644
--- a/tools/perf/util/synthetic-events.c
+++ b/tools/perf/util/synthetic-events.c
@@ -1029,7 +1029,7 @@ static int __perf_event__synthesize_kernel_mmap(struct perf_tool *tool,
* available use this, and after it is use this as a fallback for older
* kernels.
*/
- event = zalloc((sizeof(event->mmap) + machine->id_hdr_size));
+ event = zalloc((sizeof(event->mmap3) + machine->id_hdr_size));
if (event == NULL) {
pr_debug("Not enough memory synthesizing mmap event "
"for kernel modules\n");
@@ -1046,16 +1046,21 @@ static int __perf_event__synthesize_kernel_mmap(struct perf_tool *tool,
event->header.misc = PERF_RECORD_MISC_GUEST_KERNEL;
}

- size = snprintf(event->mmap.filename, sizeof(event->mmap.filename),
+ size = snprintf(event->mmap3.filename, sizeof(event->mmap3.filename),
"%s%s", machine->mmap_name, kmap->ref_reloc_sym->name) + 1;
size = PERF_ALIGN(size, sizeof(u64));
- event->mmap.header.type = PERF_RECORD_MMAP;
- event->mmap.header.size = (sizeof(event->mmap) -
- (sizeof(event->mmap.filename) - size) + machine->id_hdr_size);
- event->mmap.pgoff = kmap->ref_reloc_sym->addr;
- event->mmap.start = map->start;
- event->mmap.len = map->end - event->mmap.start;
- event->mmap.pid = machine->pid;
+ event->mmap3.header.type = PERF_RECORD_MMAP3;
+ event->mmap3.header.size = (sizeof(event->mmap3) -
+ (sizeof(event->mmap3.filename) - size) + machine->id_hdr_size);
+ event->mmap3.pgoff = kmap->ref_reloc_sym->addr;
+ event->mmap3.start = map->start;
+ event->mmap3.len = map->end - event->mmap3.start;
+ event->mmap3.pid = machine->pid;
+
+ err = sysfs__read_build_id("/sys/kernel/notes", event->mmap3.buildid,
+ BUILD_ID_SIZE);
+ if (err)
+ pr_err("Failed to read kernel build ID\n");

err = perf_tool__process_synth_event(tool, event, machine, process);
free(event);
--
2.26.2