Commit 97ebac58 authored by Tao Chen's avatar Tao Chen Committed by Andrii Nakryiko
Browse files

bpf: Add show_fdinfo for perf_event 



After commit 1b715e1b ("bpf: Support ->fill_link_info for perf_event") add
perf_event info, we can also show the info with the method of cat /proc/[fd]/fdinfo.

kprobe fdinfo:
link_type:	perf
link_id:	10
prog_tag:	bcf7977d3b93787c
prog_id:	20
name:	bpf_fentry_test1
offset:	0x0
missed:	0
addr:	0xffffffffa28a2904
event_type:	kprobe
cookie:	3735928559

uprobe fdinfo:
link_type:	perf
link_id:	13
prog_tag:	bcf7977d3b93787c
prog_id:	21
name:	/proc/self/exe
offset:	0x63dce4
ref_ctr_offset:	0x33eee2a
event_type:	uprobe
cookie:	3735928559

tracepoint fdinfo:
link_type:	perf
link_id:	11
prog_tag:	bcf7977d3b93787c
prog_id:	22
tp_name:	sched_switch
event_type:	tracepoint
cookie:	3735928559

perf_event fdinfo:
link_type:	perf
link_id:	12
prog_tag:	bcf7977d3b93787c
prog_id:	23
type:	1
config:	2
event_type:	event
cookie:	3735928559

Signed-off-by: default avatarTao Chen <chen.dylane@linux.dev>
Signed-off-by: default avatarAndrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20250606150258.3385166-1-chen.dylane@linux.dev
parent 4d2815a1

kernel/bpf/syscall.c

+120 −0
Original line number Diff line number Diff line
@@ -3795,6 +3795,32 @@ static int bpf_perf_link_fill_kprobe(const struct perf_event *event, 
	info->perf_event.kprobe.cookie = event->bpf_cookie;

	return 0;

}



static void bpf_perf_link_fdinfo_kprobe(const struct perf_event *event,

					struct seq_file *seq)

{

	const char *name;

	int err;

	u32 prog_id, type;

	u64 offset, addr;

	unsigned long missed;



	err = bpf_get_perf_event_info(event, &prog_id, &type, &name,

				      &offset, &addr, &missed);

	if (err)

		return;



	seq_printf(seq,

		   "name:\t%s\n"

		   "offset:\t%#llx\n"

		   "missed:\t%lu\n"

		   "addr:\t%#llx\n"

		   "event_type:\t%s\n"

		   "cookie:\t%llu\n",

		   name, offset, missed, addr,

		   type == BPF_FD_TYPE_KRETPROBE ?  "kretprobe" : "kprobe",

		   event->bpf_cookie);

}

#endif



#ifdef CONFIG_UPROBE_EVENTS
@@ -3823,6 +3849,31 @@ static int bpf_perf_link_fill_uprobe(const struct perf_event *event, 
	info->perf_event.uprobe.ref_ctr_offset = ref_ctr_offset;

	return 0;

}



static void bpf_perf_link_fdinfo_uprobe(const struct perf_event *event,

					struct seq_file *seq)

{

	const char *name;

	int err;

	u32 prog_id, type;

	u64 offset, ref_ctr_offset;

	unsigned long missed;



	err = bpf_get_perf_event_info(event, &prog_id, &type, &name,

				      &offset, &ref_ctr_offset, &missed);

	if (err)

		return;



	seq_printf(seq,

		   "name:\t%s\n"

		   "offset:\t%#llx\n"

		   "ref_ctr_offset:\t%#llx\n"

		   "event_type:\t%s\n"

		   "cookie:\t%llu\n",

		   name, offset, ref_ctr_offset,

		   type == BPF_FD_TYPE_URETPROBE ?  "uretprobe" : "uprobe",

		   event->bpf_cookie);

}

#endif



static int bpf_perf_link_fill_probe(const struct perf_event *event,
@@ -3891,10 +3942,79 @@ static int bpf_perf_link_fill_link_info(const struct bpf_link *link, 
	}

}



static void bpf_perf_event_link_show_fdinfo(const struct perf_event *event,

					    struct seq_file *seq)

{

	seq_printf(seq,

		   "type:\t%u\n"

		   "config:\t%llu\n"

		   "event_type:\t%s\n"

		   "cookie:\t%llu\n",

		   event->attr.type, event->attr.config,

		   "event", event->bpf_cookie);

}



static void bpf_tracepoint_link_show_fdinfo(const struct perf_event *event,

					    struct seq_file *seq)

{

	int err;

	const char *name;

	u32 prog_id;



	err = bpf_get_perf_event_info(event, &prog_id, NULL, &name, NULL,

				      NULL, NULL);

	if (err)

		return;



	seq_printf(seq,

		   "tp_name:\t%s\n"

		   "event_type:\t%s\n"

		   "cookie:\t%llu\n",

		   name, "tracepoint", event->bpf_cookie);

}



static void bpf_probe_link_show_fdinfo(const struct perf_event *event,

				       struct seq_file *seq)

{

#ifdef CONFIG_KPROBE_EVENTS

	if (event->tp_event->flags & TRACE_EVENT_FL_KPROBE)

		return bpf_perf_link_fdinfo_kprobe(event, seq);

#endif



#ifdef CONFIG_UPROBE_EVENTS

	if (event->tp_event->flags & TRACE_EVENT_FL_UPROBE)

		return bpf_perf_link_fdinfo_uprobe(event, seq);

#endif

}



static void bpf_perf_link_show_fdinfo(const struct bpf_link *link,

				      struct seq_file *seq)

{

	struct bpf_perf_link *perf_link;

	const struct perf_event *event;



	perf_link = container_of(link, struct bpf_perf_link, link);

	event = perf_get_event(perf_link->perf_file);

	if (IS_ERR(event))

		return;



	switch (event->prog->type) {

	case BPF_PROG_TYPE_PERF_EVENT:

		return bpf_perf_event_link_show_fdinfo(event, seq);

	case BPF_PROG_TYPE_TRACEPOINT:

		return bpf_tracepoint_link_show_fdinfo(event, seq);

	case BPF_PROG_TYPE_KPROBE:

		return bpf_probe_link_show_fdinfo(event, seq);

	default:

		return;

	}

}



static const struct bpf_link_ops bpf_perf_link_lops = {

	.release = bpf_perf_link_release,

	.dealloc = bpf_perf_link_dealloc,

	.fill_link_info = bpf_perf_link_fill_link_info,

	.show_fdinfo = bpf_perf_link_show_fdinfo,

};



static int bpf_perf_link_attach(const union bpf_attr *attr, struct bpf_prog *prog)