Messages in this thread Patch in this message | | | From | Jiri Olsa <> | Subject | [PATCH 03/24] perf: Add build id data in mmap2 event | Date | Mon, 9 Nov 2020 22:53:54 +0100 |
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Adding support to carry build id data in mmap2 event.
The build id data replaces maj/min/ino/ino_generation fields, whichc 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[20]; u8 build_id_size; u8 __reserved_1; u16 __reserved_2; }; };
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_BUILD_ID (1 << 14)
Signed-off-by: Jiri Olsa <jolsa@kernel.org> --- include/uapi/linux/perf_event.h | 26 +++++++++++++++++++++----- kernel/events/core.c | 31 +++++++++++++++++++++++++++---- 2 files changed, 48 insertions(+), 9 deletions(-)
diff --git a/include/uapi/linux/perf_event.h b/include/uapi/linux/perf_event.h index b95d3c485d27..b6caf61bf9fd 100644 --- a/include/uapi/linux/perf_event.h +++ b/include/uapi/linux/perf_event.h @@ -384,7 +384,8 @@ struct perf_event_attr { aux_output : 1, /* generate AUX records instead of events */ cgroup : 1, /* include cgroup events */ text_poke : 1, /* include text poke events */ - __reserved_1 : 30; + build_id : 1, /* use build id in mmap2 events */ + __reserved_1 : 29; union { __u32 wakeup_events; /* wakeup every n events */ @@ -688,6 +689,7 @@ struct perf_event_mmap_page { * * PERF_RECORD_MISC_EXACT_IP - PERF_RECORD_SAMPLE of precise events * PERF_RECORD_MISC_SWITCH_OUT_PREEMPT - PERF_RECORD_SWITCH* events + * PERF_RECORD_MISC_BUILD_ID - PERF_RECORD_MMAP2 event * * * PERF_RECORD_MISC_EXACT_IP: @@ -697,9 +699,13 @@ struct perf_event_mmap_page { * * PERF_RECORD_MISC_SWITCH_OUT_PREEMPT: * Indicates that thread was preempted in TASK_RUNNING state. + * + * PERF_RECORD_MISC_BUILD_ID: + * Indicates that mmap2 event carries build id data. */ #define PERF_RECORD_MISC_EXACT_IP (1 << 14) #define PERF_RECORD_MISC_SWITCH_OUT_PREEMPT (1 << 14) +#define PERF_RECORD_MISC_BUILD_ID (1 << 14) /* * Reserve the last bit to indicate some extended misc field */ @@ -911,10 +917,20 @@ enum perf_event_type { * u64 addr; * u64 len; * u64 pgoff; - * u32 maj; - * u32 min; - * u64 ino; - * u64 ino_generation; + * union { + * struct { + * u32 maj; + * u32 min; + * u64 ino; + * u64 ino_generation; + * }; + * struct { + * u8 build_id[20]; + * u8 build_id_size; + * u8 __reserved_1; + * u16 __reserved_2; + * }; + * }; * u32 prot, flags; * char filename[]; * struct sample_id sample_id; diff --git a/kernel/events/core.c b/kernel/events/core.c index da467e1dd49a..808473b6ce85 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -51,6 +51,7 @@ #include <linux/proc_ns.h> #include <linux/mount.h> #include <linux/min_heap.h> +#include <linux/buildid.h> #include "internal.h" @@ -395,6 +396,7 @@ 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); @@ -4672,6 +4674,8 @@ 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) @@ -7942,6 +7946,8 @@ struct perf_mmap_event { u64 ino; u64 ino_generation; u32 prot, flags; + u8 build_id[BUILD_ID_SIZE]; + u32 build_id_size; struct { struct perf_event_header header; @@ -7997,13 +8003,23 @@ 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); + if (event->attr.mmap2 && event->attr.build_id) + mmap_event->event_id.header.misc |= PERF_RECORD_MISC_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 (event->attr.build_id) { + u8 size[4] = { (u8) mmap_event->build_id_size, 0, 0, 0 }; + + __output_copy(&handle, mmap_event->build_id, BUILD_ID_SIZE); + __output_copy(&handle, size, 4); + } 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); } @@ -8132,6 +8148,11 @@ static void perf_event_mmap_event(struct perf_mmap_event *mmap_event) mmap_event->event_id.header.size = sizeof(mmap_event->event_id) + size; + if (atomic_read(&nr_build_id_events)) { + build_id_parse_size(vma, mmap_event->build_id, + &mmap_event->build_id_size); + } + perf_iterate_sb(perf_event_mmap_output, mmap_event, NULL); @@ -11069,6 +11090,8 @@ 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) -- 2.26.2
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