By adding support for ->show_fdinfo to the perf_event link, users will be
able to examine it through the task's fdinfo. The expected result is as
follows:
$ cat /proc/9637/fdinfo/11
pos: 0
flags: 02000000
mnt_id: 15
ino: 2094
link_type: perf
link_id: 1
prog_tag: a04f5eef06a7f555
prog_id: 5
func: kernel_clone
addr: ffffffff8d0bc310
offset: 0
Signed-off-by: Yafang Shao <laoar.shao@xxxxxxxxx>
---
kernel/bpf/syscall.c | 27 +++++++++++++++++++++++++++
1 file changed, 27 insertions(+)
diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index 92a57ef..e6b5127 100644
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -3297,9 +3297,36 @@ static void bpf_perf_link_dealloc(struct bpf_link *link)
kfree(perf_link);
}
+static void bpf_perf_link_show_fdinfo(const struct bpf_link *link,
+ struct seq_file *seq)
+{
+ struct bpf_perf_link *perf_link = container_of(link, struct bpf_perf_link, link);
+ const struct perf_event *event;
+ u64 probe_offset, probe_addr;
+ u32 prog_id, fd_type;
+ const char *buf;
+ int err;
+
+ event = perf_get_event(perf_link->perf_file);
+ if (IS_ERR(event))
+ return;
+
+ err = bpf_get_perf_event_info(event, &prog_id, &fd_type,
+ &buf, &probe_offset,
+ &probe_addr);
+ if (err)
+ return;
+
+ if (buf)
+ seq_printf(seq, "func:\t%s\n", buf);
+ seq_printf(seq, "addr:\t%llx\n", probe_addr);
+ seq_printf(seq, "offset:\t%llu\n", probe_offset);
+}
+
static const struct bpf_link_ops bpf_perf_link_lops = {
.release = bpf_perf_link_release,
.dealloc = bpf_perf_link_dealloc,
+ .show_fdinfo = bpf_perf_link_show_fdinfo,
};
static int bpf_perf_link_attach(const union bpf_attr *attr, struct bpf_prog *prog)
--
1.8.3.1
