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authorJiri Olsa <jolsa@kernel.org>2021-01-14 14:40:44 +0100
committerAlexei Starovoitov <ast@kernel.org>2021-01-14 19:29:58 -0800
commit88a16a1309333e43d328621ece3e9fa37027e8eb (patch)
tree75de6df2421dce6b1859d71c75562be1e70ee1a5 /kernel
parent921f88fc891922b325b3668cd026a386571ed602 (diff)
perf: Add build id data in mmap2 event
Adding support to carry build id data in mmap2 event. The build id data replaces maj/min/ino/ino_generation fields, which are also used to identify map's binary, so it's ok to replace them with build id data: union { struct { u32 maj; u32 min; u64 ino; u64 ino_generation; }; struct { u8 build_id_size; u8 __reserved_1; u16 __reserved_2; u8 build_id[20]; }; }; Replaced maj/min/ino/ino_generation fields give us size of 24 bytes. We use 20 bytes for build id data, 1 byte for size and rest is unused. There's new misc bit for mmap2 to signal there's build id data in it: #define PERF_RECORD_MISC_MMAP_BUILD_ID (1 << 14) Signed-off-by: Jiri Olsa <jolsa@kernel.org> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lore.kernel.org/bpf/20210114134044.1418404-4-jolsa@kernel.org
Diffstat (limited to 'kernel')
-rw-r--r--kernel/events/core.c32
1 files changed, 28 insertions, 4 deletions
diff --git a/kernel/events/core.c b/kernel/events/core.c
index 55d18791a72d..c37401e3e5f7 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -53,6 +53,7 @@
#include <linux/min_heap.h>
#include <linux/highmem.h>
#include <linux/pgtable.h>
+#include <linux/buildid.h>
#include "internal.h"
@@ -397,6 +398,7 @@ static atomic_t nr_ksymbol_events __read_mostly;
static atomic_t nr_bpf_events __read_mostly;
static atomic_t nr_cgroup_events __read_mostly;
static atomic_t nr_text_poke_events __read_mostly;
+static atomic_t nr_build_id_events __read_mostly;
static LIST_HEAD(pmus);
static DEFINE_MUTEX(pmus_lock);
@@ -4673,6 +4675,8 @@ static void unaccount_event(struct perf_event *event)
dec = true;
if (event->attr.mmap || event->attr.mmap_data)
atomic_dec(&nr_mmap_events);
+ if (event->attr.build_id)
+ atomic_dec(&nr_build_id_events);
if (event->attr.comm)
atomic_dec(&nr_comm_events);
if (event->attr.namespaces)
@@ -8046,6 +8050,8 @@ struct perf_mmap_event {
u64 ino;
u64 ino_generation;
u32 prot, flags;
+ u8 build_id[BUILD_ID_SIZE_MAX];
+ u32 build_id_size;
struct {
struct perf_event_header header;
@@ -8077,6 +8083,7 @@ static void perf_event_mmap_output(struct perf_event *event,
struct perf_sample_data sample;
int size = mmap_event->event_id.header.size;
u32 type = mmap_event->event_id.header.type;
+ bool use_build_id;
int ret;
if (!perf_event_mmap_match(event, data))
@@ -8101,13 +8108,25 @@ static void perf_event_mmap_output(struct perf_event *event,
mmap_event->event_id.pid = perf_event_pid(event, current);
mmap_event->event_id.tid = perf_event_tid(event, current);
+ use_build_id = event->attr.build_id && mmap_event->build_id_size;
+
+ if (event->attr.mmap2 && use_build_id)
+ mmap_event->event_id.header.misc |= PERF_RECORD_MISC_MMAP_BUILD_ID;
+
perf_output_put(&handle, mmap_event->event_id);
if (event->attr.mmap2) {
- perf_output_put(&handle, mmap_event->maj);
- perf_output_put(&handle, mmap_event->min);
- perf_output_put(&handle, mmap_event->ino);
- perf_output_put(&handle, mmap_event->ino_generation);
+ if (use_build_id) {
+ u8 size[4] = { (u8) mmap_event->build_id_size, 0, 0, 0 };
+
+ __output_copy(&handle, size, 4);
+ __output_copy(&handle, mmap_event->build_id, BUILD_ID_SIZE_MAX);
+ } else {
+ perf_output_put(&handle, mmap_event->maj);
+ perf_output_put(&handle, mmap_event->min);
+ perf_output_put(&handle, mmap_event->ino);
+ perf_output_put(&handle, mmap_event->ino_generation);
+ }
perf_output_put(&handle, mmap_event->prot);
perf_output_put(&handle, mmap_event->flags);
}
@@ -8236,6 +8255,9 @@ got_name:
mmap_event->event_id.header.size = sizeof(mmap_event->event_id) + size;
+ if (atomic_read(&nr_build_id_events))
+ build_id_parse(vma, mmap_event->build_id, &mmap_event->build_id_size);
+
perf_iterate_sb(perf_event_mmap_output,
mmap_event,
NULL);
@@ -11172,6 +11194,8 @@ static void account_event(struct perf_event *event)
inc = true;
if (event->attr.mmap || event->attr.mmap_data)
atomic_inc(&nr_mmap_events);
+ if (event->attr.build_id)
+ atomic_inc(&nr_build_id_events);
if (event->attr.comm)
atomic_inc(&nr_comm_events);
if (event->attr.namespaces)