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Commit ea317b26 authored by Kaixu Xia's avatar Kaixu Xia Committed by David S. Miller
Browse files

bpf: Add new bpf map type to store the pointer to struct perf_event 



Introduce a new bpf map type 'BPF_MAP_TYPE_PERF_EVENT_ARRAY'.
This map only stores the pointer to struct perf_event. The
user space event FDs from perf_event_open() syscall are converted
to the pointer to struct perf_event and stored in map.

Signed-off-by: default avatarKaixu Xia <xiakaixu@huawei.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 2a36f0b9

include/linux/bpf.h

+1 −0
Original line number Diff line number Diff line
@@ -10,6 +10,7 @@ 
#include <uapi/linux/bpf.h>

#include <linux/workqueue.h>

#include <linux/file.h>

#include <linux/perf_event.h>



struct bpf_map;

include/uapi/linux/bpf.h

+1 −0
Original line number Diff line number Diff line
@@ -114,6 +114,7 @@ enum bpf_map_type { 
	BPF_MAP_TYPE_HASH,

	BPF_MAP_TYPE_ARRAY,

	BPF_MAP_TYPE_PROG_ARRAY,

	BPF_MAP_TYPE_PERF_EVENT_ARRAY,

};



enum bpf_prog_type {

kernel/bpf/arraymap.c

+57 −0
Original line number Diff line number Diff line
@@ -273,3 +273,60 @@ static int __init register_prog_array_map(void) 
	return 0;

}

late_initcall(register_prog_array_map);



static void perf_event_array_map_free(struct bpf_map *map)

{

	bpf_fd_array_map_clear(map);

	fd_array_map_free(map);

}



static void *perf_event_fd_array_get_ptr(struct bpf_map *map, int fd)

{

	struct perf_event *event;

	const struct perf_event_attr *attr;



	event = perf_event_get(fd);

	if (IS_ERR(event))

		return event;



	attr = perf_event_attrs(event);

	if (IS_ERR(attr))

		return (void *)attr;



	if (attr->type != PERF_TYPE_RAW &&

	    attr->type != PERF_TYPE_HARDWARE) {

		perf_event_release_kernel(event);

		return ERR_PTR(-EINVAL);

	}

	return event;

}



static void perf_event_fd_array_put_ptr(void *ptr)

{

	struct perf_event *event = ptr;



	perf_event_release_kernel(event);

}



static const struct bpf_map_ops perf_event_array_ops = {

	.map_alloc = fd_array_map_alloc,

	.map_free = perf_event_array_map_free,

	.map_get_next_key = array_map_get_next_key,

	.map_lookup_elem = fd_array_map_lookup_elem,

	.map_update_elem = fd_array_map_update_elem,

	.map_delete_elem = fd_array_map_delete_elem,

	.map_fd_get_ptr = perf_event_fd_array_get_ptr,

	.map_fd_put_ptr = perf_event_fd_array_put_ptr,

};



static struct bpf_map_type_list perf_event_array_type __read_mostly = {

	.ops = &perf_event_array_ops,

	.type = BPF_MAP_TYPE_PERF_EVENT_ARRAY,

};



static int __init register_perf_event_array_map(void)

{

	bpf_register_map_type(&perf_event_array_type);

	return 0;

}

late_initcall(register_perf_event_array_map);