From 88a16a1309333e43d328621ece3e9fa37027e8eb Mon Sep 17 00:00:00 2001 From: Jiri Olsa Date: Thu, 14 Jan 2021 14:40:44 +0100 Subject: 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 Signed-off-by: Alexei Starovoitov Acked-by: Peter Zijlstra (Intel) Link: https://lore.kernel.org/bpf/20210114134044.1418404-4-jolsa@kernel.org --- kernel/events/core.c | 32 ++++++++++++++++++++++++++++---- 1 file changed, 28 insertions(+), 4 deletions(-) (limited to 'kernel/events') 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 #include #include +#include #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) -- cgit