diff options
| -rw-r--r-- | include/linux/perf_event.h | 8 | ||||
| -rw-r--r-- | include/uapi/linux/perf_event.h | 21 | ||||
| -rw-r--r-- | kernel/events/core.c | 90 |
3 files changed, 117 insertions, 2 deletions
diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h index b4bb32082342..46fe5cfb5163 100644 --- a/include/linux/perf_event.h +++ b/include/linux/perf_event.h @@ -1232,6 +1232,9 @@ extern void perf_event_exec(void); extern void perf_event_comm(struct task_struct *tsk, bool exec); extern void perf_event_namespaces(struct task_struct *tsk); extern void perf_event_fork(struct task_struct *tsk); +extern void perf_event_text_poke(const void *addr, + const void *old_bytes, size_t old_len, + const void *new_bytes, size_t new_len); /* Callchains */ DECLARE_PER_CPU(struct perf_callchain_entry, perf_callchain_entry); @@ -1479,6 +1482,11 @@ static inline void perf_event_exec(void) { } static inline void perf_event_comm(struct task_struct *tsk, bool exec) { } static inline void perf_event_namespaces(struct task_struct *tsk) { } static inline void perf_event_fork(struct task_struct *tsk) { } +static inline void perf_event_text_poke(const void *addr, + const void *old_bytes, + size_t old_len, + const void *new_bytes, + size_t new_len) { } static inline void perf_event_init(void) { } static inline int perf_swevent_get_recursion_context(void) { return -1; } static inline void perf_swevent_put_recursion_context(int rctx) { } diff --git a/include/uapi/linux/perf_event.h b/include/uapi/linux/perf_event.h index 7b2d6fc9e6ed..e5bee6c17b86 100644 --- a/include/uapi/linux/perf_event.h +++ b/include/uapi/linux/perf_event.h @@ -383,7 +383,8 @@ struct perf_event_attr { bpf_event : 1, /* include bpf events */ aux_output : 1, /* generate AUX records instead of events */ cgroup : 1, /* include cgroup events */ - __reserved_1 : 31; + text_poke : 1, /* include text poke events */ + __reserved_1 : 30; union { __u32 wakeup_events; /* wakeup every n events */ @@ -1024,6 +1025,24 @@ enum perf_event_type { */ PERF_RECORD_CGROUP = 19, + /* + * Records changes to kernel text i.e. self-modified code. 'old_len' is + * the number of old bytes, 'new_len' is the number of new bytes. Either + * 'old_len' or 'new_len' may be zero to indicate, for example, the + * addition or removal of a trampoline. 'bytes' contains the old bytes + * followed immediately by the new bytes. + * + * struct { + * struct perf_event_header header; + * u64 addr; + * u16 old_len; + * u16 new_len; + * u8 bytes[]; + * struct sample_id sample_id; + * }; + */ + PERF_RECORD_TEXT_POKE = 20, + PERF_RECORD_MAX, /* non-ABI */ }; diff --git a/kernel/events/core.c b/kernel/events/core.c index 856d98c36f56..9b8f92500833 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -394,6 +394,7 @@ static atomic_t nr_switch_events __read_mostly; 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 LIST_HEAD(pmus); static DEFINE_MUTEX(pmus_lock); @@ -4575,7 +4576,7 @@ static bool is_sb_event(struct perf_event *event) if (attr->mmap || attr->mmap_data || attr->mmap2 || attr->comm || attr->comm_exec || attr->task || attr->ksymbol || - attr->context_switch || + attr->context_switch || attr->text_poke || attr->bpf_event) return true; return false; @@ -4651,6 +4652,8 @@ static void unaccount_event(struct perf_event *event) atomic_dec(&nr_ksymbol_events); if (event->attr.bpf_event) atomic_dec(&nr_bpf_events); + if (event->attr.text_poke) + atomic_dec(&nr_text_poke_events); if (dec) { if (!atomic_add_unless(&perf_sched_count, -1, 1)) @@ -8628,6 +8631,89 @@ void perf_event_bpf_event(struct bpf_prog *prog, perf_iterate_sb(perf_event_bpf_output, &bpf_event, NULL); } +struct perf_text_poke_event { + const void *old_bytes; + const void *new_bytes; + size_t pad; + u16 old_len; + u16 new_len; + + struct { + struct perf_event_header header; + + u64 addr; + } event_id; +}; + +static int perf_event_text_poke_match(struct perf_event *event) +{ + return event->attr.text_poke; +} + +static void perf_event_text_poke_output(struct perf_event *event, void *data) +{ + struct perf_text_poke_event *text_poke_event = data; + struct perf_output_handle handle; + struct perf_sample_data sample; + u64 padding = 0; + int ret; + + if (!perf_event_text_poke_match(event)) + return; + + perf_event_header__init_id(&text_poke_event->event_id.header, &sample, event); + + ret = perf_output_begin(&handle, event, text_poke_event->event_id.header.size); + if (ret) + return; + + perf_output_put(&handle, text_poke_event->event_id); + perf_output_put(&handle, text_poke_event->old_len); + perf_output_put(&handle, text_poke_event->new_len); + + __output_copy(&handle, text_poke_event->old_bytes, text_poke_event->old_len); + __output_copy(&handle, text_poke_event->new_bytes, text_poke_event->new_len); + + if (text_poke_event->pad) + __output_copy(&handle, &padding, text_poke_event->pad); + + perf_event__output_id_sample(event, &handle, &sample); + + perf_output_end(&handle); +} + +void perf_event_text_poke(const void *addr, const void *old_bytes, + size_t old_len, const void *new_bytes, size_t new_len) +{ + struct perf_text_poke_event text_poke_event; + size_t tot, pad; + + if (!atomic_read(&nr_text_poke_events)) + return; + + tot = sizeof(text_poke_event.old_len) + old_len; + tot += sizeof(text_poke_event.new_len) + new_len; + pad = ALIGN(tot, sizeof(u64)) - tot; + + text_poke_event = (struct perf_text_poke_event){ + .old_bytes = old_bytes, + .new_bytes = new_bytes, + .pad = pad, + .old_len = old_len, + .new_len = new_len, + .event_id = { + .header = { + .type = PERF_RECORD_TEXT_POKE, + .misc = PERF_RECORD_MISC_KERNEL, + .size = sizeof(text_poke_event.event_id) + tot + pad, + }, + .addr = (unsigned long)addr, + }, + }; + + perf_iterate_sb(perf_event_text_poke_output, &text_poke_event, NULL); +} + void perf_event_itrace_started(struct perf_event *event) { event->attach_state |= PERF_ATTACH_ITRACE; @@ -10945,6 +11031,8 @@ static void account_event(struct perf_event *event) atomic_inc(&nr_ksymbol_events); if (event->attr.bpf_event) atomic_inc(&nr_bpf_events); + if (event->attr.text_poke) + atomic_inc(&nr_text_poke_events); if (inc) { /* |