diff options
| -rw-r--r-- | include/linux/bpf.h | 4 | ||||
| -rw-r--r-- | include/linux/perf_event.h | 4 | ||||
| -rw-r--r-- | kernel/events/core.c | 89 |
3 files changed, 96 insertions, 1 deletions
diff --git a/include/linux/bpf.h b/include/linux/bpf.h index 11134238417d..9a904f63f8c1 100644 --- a/include/linux/bpf.h +++ b/include/linux/bpf.h @@ -297,6 +297,10 @@ static inline struct bpf_prog *bpf_prog_add(struct bpf_prog *prog, int i) static inline void bpf_prog_put(struct bpf_prog *prog) { } +static inline struct bpf_prog *bpf_prog_inc(struct bpf_prog *prog) +{ + return ERR_PTR(-EOPNOTSUPP); +} #endif /* CONFIG_BPF_SYSCALL */ /* verifier prototypes for helper functions called from eBPF programs */ diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h index 97bfe62f30d7..ccb73a58113d 100644 --- a/include/linux/perf_event.h +++ b/include/linux/perf_event.h @@ -679,6 +679,10 @@ struct perf_event { u64 (*clock)(void); perf_overflow_handler_t overflow_handler; void *overflow_handler_context; +#ifdef CONFIG_BPF_SYSCALL + perf_overflow_handler_t orig_overflow_handler; + struct bpf_prog *prog; +#endif #ifdef CONFIG_EVENT_TRACING struct trace_event_call *tp_event; diff --git a/kernel/events/core.c b/kernel/events/core.c index 3cfabdf7b942..85bf4c37911f 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -7022,7 +7022,7 @@ static int __perf_event_overflow(struct perf_event *event, irq_work_queue(&event->pending); } - event->overflow_handler(event, data, regs); + READ_ONCE(event->overflow_handler)(event, data, regs); if (*perf_event_fasync(event) && event->pending_kill) { event->pending_wakeup = 1; @@ -7637,11 +7637,83 @@ static void perf_event_free_filter(struct perf_event *event) ftrace_profile_free_filter(event); } +#ifdef CONFIG_BPF_SYSCALL +static void bpf_overflow_handler(struct perf_event *event, + struct perf_sample_data *data, + struct pt_regs *regs) +{ + struct bpf_perf_event_data_kern ctx = { + .data = data, + .regs = regs, + }; + int ret = 0; + + preempt_disable(); + if (unlikely(__this_cpu_inc_return(bpf_prog_active) != 1)) + goto out; + rcu_read_lock(); + ret = BPF_PROG_RUN(event->prog, (void *)&ctx); + rcu_read_unlock(); +out: + __this_cpu_dec(bpf_prog_active); + preempt_enable(); + if (!ret) + return; + + event->orig_overflow_handler(event, data, regs); +} + +static int perf_event_set_bpf_handler(struct perf_event *event, u32 prog_fd) +{ + struct bpf_prog *prog; + + if (event->overflow_handler_context) + /* hw breakpoint or kernel counter */ + return -EINVAL; + + if (event->prog) + return -EEXIST; + + prog = bpf_prog_get_type(prog_fd, BPF_PROG_TYPE_PERF_EVENT); + if (IS_ERR(prog)) + return PTR_ERR(prog); + + event->prog = prog; + event->orig_overflow_handler = READ_ONCE(event->overflow_handler); + WRITE_ONCE(event->overflow_handler, bpf_overflow_handler); + return 0; +} + +static void perf_event_free_bpf_handler(struct perf_event *event) +{ + struct bpf_prog *prog = event->prog; + + if (!prog) + return; + + WRITE_ONCE(event->overflow_handler, event->orig_overflow_handler); + event->prog = NULL; + bpf_prog_put(prog); +} +#else +static int perf_event_set_bpf_handler(struct perf_event *event, u32 prog_fd) +{ + return -EOPNOTSUPP; +} +static void perf_event_free_bpf_handler(struct perf_event *event) +{ +} +#endif + static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd) { bool is_kprobe, is_tracepoint; struct bpf_prog *prog; + if (event->attr.type == PERF_TYPE_HARDWARE || + event->attr.type == PERF_TYPE_SOFTWARE) + return perf_event_set_bpf_handler(event, prog_fd); + if (event->attr.type != PERF_TYPE_TRACEPOINT) return -EINVAL; @@ -7682,6 +7754,8 @@ static void perf_event_free_bpf_prog(struct perf_event *event) { struct bpf_prog *prog; + perf_event_free_bpf_handler(event); + if (!event->tp_event) return; @@ -8998,6 +9072,19 @@ perf_event_alloc(struct perf_event_attr *attr, int cpu, if (!overflow_handler && parent_event) { overflow_handler = parent_event->overflow_handler; context = parent_event->overflow_handler_context; +#ifdef CONFIG_BPF_SYSCALL + if (overflow_handler == bpf_overflow_handler) { + struct bpf_prog *prog = bpf_prog_inc(parent_event->prog); + + if (IS_ERR(prog)) { + err = PTR_ERR(prog); + goto err_ns; + } + event->prog = prog; + event->orig_overflow_handler = + parent_event->orig_overflow_handler; + } +#endif } if (overflow_handler) { |