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-rw-r--r--kernel/events/core.c89
1 files changed, 88 insertions, 1 deletions
diff --git a/kernel/events/core.c b/kernel/events/core.c
index 7c0d263f6bc5..c6e47e97b33f 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -7079,7 +7079,7 @@ 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;
@@ -7694,11 +7694,83 @@ 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;
@@ -7739,6 +7811,8 @@ 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;
@@ -9055,6 +9129,19 @@ 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;
+#if defined(CONFIG_BPF_SYSCALL) && defined(CONFIG_EVENT_TRACING)
+ 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) {