1 /* Copyright (c) 2011-2014 PLUMgrid, http://plumgrid.com
3 * This program is free software; you can redistribute it and/or
4 * modify it under the terms of version 2 of the GNU General Public
5 * License as published by the Free Software Foundation.
7 * This program is distributed in the hope that it will be useful, but
8 * WITHOUT ANY WARRANTY; without even the implied warranty of
9 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
10 * General Public License for more details.
12 #include <linux/bpf.h>
13 #include <linux/rcupdate.h>
15 /* If kernel subsystem is allowing eBPF programs to call this function,
16 * inside its own verifier_ops->get_func_proto() callback it should return
17 * bpf_map_lookup_elem_proto, so that verifier can properly check the arguments
19 * Different map implementations will rely on rcu in map methods
20 * lookup/update/delete, therefore eBPF programs must run under rcu lock
21 * if program is allowed to access maps, so check rcu_read_lock_held in
22 * all three functions.
24 static u64 bpf_map_lookup_elem(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5)
26 /* verifier checked that R1 contains a valid pointer to bpf_map
27 * and R2 points to a program stack and map->key_size bytes were
30 struct bpf_map *map = (struct bpf_map *) (unsigned long) r1;
31 void *key = (void *) (unsigned long) r2;
34 WARN_ON_ONCE(!rcu_read_lock_held());
36 value = map->ops->map_lookup_elem(map, key);
38 /* lookup() returns either pointer to element value or NULL
39 * which is the meaning of PTR_TO_MAP_VALUE_OR_NULL type
41 return (unsigned long) value;
44 struct bpf_func_proto bpf_map_lookup_elem_proto = {
45 .func = bpf_map_lookup_elem,
47 .ret_type = RET_PTR_TO_MAP_VALUE_OR_NULL,
48 .arg1_type = ARG_CONST_MAP_PTR,
49 .arg2_type = ARG_PTR_TO_MAP_KEY,
52 static u64 bpf_map_update_elem(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5)
54 struct bpf_map *map = (struct bpf_map *) (unsigned long) r1;
55 void *key = (void *) (unsigned long) r2;
56 void *value = (void *) (unsigned long) r3;
58 WARN_ON_ONCE(!rcu_read_lock_held());
60 return map->ops->map_update_elem(map, key, value, r4);
63 struct bpf_func_proto bpf_map_update_elem_proto = {
64 .func = bpf_map_update_elem,
66 .ret_type = RET_INTEGER,
67 .arg1_type = ARG_CONST_MAP_PTR,
68 .arg2_type = ARG_PTR_TO_MAP_KEY,
69 .arg3_type = ARG_PTR_TO_MAP_VALUE,
70 .arg4_type = ARG_ANYTHING,
73 static u64 bpf_map_delete_elem(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5)
75 struct bpf_map *map = (struct bpf_map *) (unsigned long) r1;
76 void *key = (void *) (unsigned long) r2;
78 WARN_ON_ONCE(!rcu_read_lock_held());
80 return map->ops->map_delete_elem(map, key);
83 struct bpf_func_proto bpf_map_delete_elem_proto = {
84 .func = bpf_map_delete_elem,
86 .ret_type = RET_INTEGER,
87 .arg1_type = ARG_CONST_MAP_PTR,
88 .arg2_type = ARG_PTR_TO_MAP_KEY,