[PATCH 14/25] perf tools: Allow mmap2 event to synthesize kernel image

Jiri Olsa
2020-11-26T17:01:52Z

Allow mmap2 event to synthesize kernel image,
so we can synthesize kernel build id data in
following changes.

It's enabled by new symbol_conf.buildid_mmap2
bool, which will be switched in following
changes.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
---
tools/perf/util/symbol_conf.h | 3 ++-
tools/perf/util/synthetic-events.c | 40 ++++++++++++++++++++----------
2 files changed, 29 insertions(+), 14 deletions(-)

diff --git a/tools/perf/util/symbol_conf.h b/tools/perf/util/symbol_conf.h
index b916afb95ec5..b18f9c8dbb75 100644
--- a/tools/perf/util/symbol_conf.h
+++ b/tools/perf/util/symbol_conf.h
@@ -42,7 +42,8 @@ struct symbol_conf {
report_block,
report_individual_block,
inline_name,
- disable_add2line_warn;
+ disable_add2line_warn,
+ buildid_mmap2;
const char *vmlinux_name,
*kallsyms_name,
*source_prefix,
diff --git a/tools/perf/util/synthetic-events.c b/tools/perf/util/synthetic-events.c
index 8a23391558cf..872df6d6dbef 100644
--- a/tools/perf/util/synthetic-events.c
+++ b/tools/perf/util/synthetic-events.c
@@ -988,11 +988,12 @@ static int __perf_event__synthesize_kernel_mmap(struct perf_tool *tool,
perf_event__handler_t process,
struct machine *machine)
{
- size_t size;
+ union perf_event *event;
+ size_t size = symbol_conf.buildid_mmap2 ?
+ sizeof(event->mmap2) : sizeof(event->mmap);
struct map *map = machine__kernel_map(machine);
struct kmap *kmap;
int err;
- union perf_event *event;

if (map == NULL)
return -1;
@@ -1006,7 +1007,7 @@ 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(size + machine->id_hdr_size);
if (event == NULL) {
pr_debug("Not enough memory synthesizing mmap event "
"for kernel modules\n");
@@ -1023,16 +1024,29 @@ 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),
- "%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;
+ if (symbol_conf.buildid_mmap2) {
+ size = snprintf(event->mmap2.filename, sizeof(event->mmap2.filename),
+ "%s%s", machine->mmap_name, kmap->ref_reloc_sym->name) + 1;
+ size = PERF_ALIGN(size, sizeof(u64));
+ event->mmap2.header.type = PERF_RECORD_MMAP2;
+ event->mmap2.header.size = (sizeof(event->mmap2) -
+ (sizeof(event->mmap2.filename) - size) + machine->id_hdr_size);
+ event->mmap2.pgoff = kmap->ref_reloc_sym->addr;
+ event->mmap2.start = map->start;
+ event->mmap2.len = map->end - event->mmap.start;
+ event->mmap2.pid = machine->pid;
+ } else {
+ size = snprintf(event->mmap.filename, sizeof(event->mmap.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;
+ }

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