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d0003ec0 AS |
1 | /* Copyright (c) 2011-2014 PLUMgrid, http://plumgrid.com |
2 | * | |
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. | |
6 | * | |
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. | |
11 | */ | |
12 | #include <linux/bpf.h> | |
13 | #include <linux/rcupdate.h> | |
03e69b50 | 14 | #include <linux/random.h> |
c04167ce | 15 | #include <linux/smp.h> |
d0003ec0 AS |
16 | |
17 | /* If kernel subsystem is allowing eBPF programs to call this function, | |
18 | * inside its own verifier_ops->get_func_proto() callback it should return | |
19 | * bpf_map_lookup_elem_proto, so that verifier can properly check the arguments | |
20 | * | |
21 | * Different map implementations will rely on rcu in map methods | |
22 | * lookup/update/delete, therefore eBPF programs must run under rcu lock | |
23 | * if program is allowed to access maps, so check rcu_read_lock_held in | |
24 | * all three functions. | |
25 | */ | |
26 | static u64 bpf_map_lookup_elem(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5) | |
27 | { | |
28 | /* verifier checked that R1 contains a valid pointer to bpf_map | |
29 | * and R2 points to a program stack and map->key_size bytes were | |
30 | * initialized | |
31 | */ | |
32 | struct bpf_map *map = (struct bpf_map *) (unsigned long) r1; | |
33 | void *key = (void *) (unsigned long) r2; | |
34 | void *value; | |
35 | ||
36 | WARN_ON_ONCE(!rcu_read_lock_held()); | |
37 | ||
38 | value = map->ops->map_lookup_elem(map, key); | |
39 | ||
40 | /* lookup() returns either pointer to element value or NULL | |
41 | * which is the meaning of PTR_TO_MAP_VALUE_OR_NULL type | |
42 | */ | |
43 | return (unsigned long) value; | |
44 | } | |
45 | ||
a2c83fff | 46 | const struct bpf_func_proto bpf_map_lookup_elem_proto = { |
d0003ec0 AS |
47 | .func = bpf_map_lookup_elem, |
48 | .gpl_only = false, | |
49 | .ret_type = RET_PTR_TO_MAP_VALUE_OR_NULL, | |
50 | .arg1_type = ARG_CONST_MAP_PTR, | |
51 | .arg2_type = ARG_PTR_TO_MAP_KEY, | |
52 | }; | |
53 | ||
54 | static u64 bpf_map_update_elem(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5) | |
55 | { | |
56 | struct bpf_map *map = (struct bpf_map *) (unsigned long) r1; | |
57 | void *key = (void *) (unsigned long) r2; | |
58 | void *value = (void *) (unsigned long) r3; | |
59 | ||
60 | WARN_ON_ONCE(!rcu_read_lock_held()); | |
61 | ||
62 | return map->ops->map_update_elem(map, key, value, r4); | |
63 | } | |
64 | ||
a2c83fff | 65 | const struct bpf_func_proto bpf_map_update_elem_proto = { |
d0003ec0 AS |
66 | .func = bpf_map_update_elem, |
67 | .gpl_only = false, | |
68 | .ret_type = RET_INTEGER, | |
69 | .arg1_type = ARG_CONST_MAP_PTR, | |
70 | .arg2_type = ARG_PTR_TO_MAP_KEY, | |
71 | .arg3_type = ARG_PTR_TO_MAP_VALUE, | |
72 | .arg4_type = ARG_ANYTHING, | |
73 | }; | |
74 | ||
75 | static u64 bpf_map_delete_elem(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5) | |
76 | { | |
77 | struct bpf_map *map = (struct bpf_map *) (unsigned long) r1; | |
78 | void *key = (void *) (unsigned long) r2; | |
79 | ||
80 | WARN_ON_ONCE(!rcu_read_lock_held()); | |
81 | ||
82 | return map->ops->map_delete_elem(map, key); | |
83 | } | |
84 | ||
a2c83fff | 85 | const struct bpf_func_proto bpf_map_delete_elem_proto = { |
d0003ec0 AS |
86 | .func = bpf_map_delete_elem, |
87 | .gpl_only = false, | |
88 | .ret_type = RET_INTEGER, | |
89 | .arg1_type = ARG_CONST_MAP_PTR, | |
90 | .arg2_type = ARG_PTR_TO_MAP_KEY, | |
91 | }; | |
03e69b50 DB |
92 | |
93 | static u64 bpf_get_prandom_u32(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5) | |
94 | { | |
95 | return prandom_u32(); | |
96 | } | |
97 | ||
98 | const struct bpf_func_proto bpf_get_prandom_u32_proto = { | |
99 | .func = bpf_get_prandom_u32, | |
100 | .gpl_only = false, | |
101 | .ret_type = RET_INTEGER, | |
102 | }; | |
c04167ce DB |
103 | |
104 | static u64 bpf_get_smp_processor_id(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5) | |
105 | { | |
106 | return raw_smp_processor_id(); | |
107 | } | |
108 | ||
109 | const struct bpf_func_proto bpf_get_smp_processor_id_proto = { | |
110 | .func = bpf_get_smp_processor_id, | |
111 | .gpl_only = false, | |
112 | .ret_type = RET_INTEGER, | |
113 | }; |