Commit | Line | Data |
---|---|---|
25763b3c | 1 | // SPDX-License-Identifier: GPL-2.0-only |
56f668df | 2 | /* Copyright (c) 2017 Facebook |
56f668df MKL |
3 | */ |
4 | #include <linux/slab.h> | |
5 | #include <linux/bpf.h> | |
40ec00ab | 6 | #include <linux/btf.h> |
56f668df MKL |
7 | |
8 | #include "map_in_map.h" | |
9 | ||
10 | struct bpf_map *bpf_map_meta_alloc(int inner_map_ufd) | |
11 | { | |
12 | struct bpf_map *inner_map, *inner_map_meta; | |
9d5564dd | 13 | u32 inner_map_meta_size; |
56f668df | 14 | struct fd f; |
f73e601a | 15 | int ret; |
56f668df MKL |
16 | |
17 | f = fdget(inner_map_ufd); | |
18 | inner_map = __bpf_map_get(f); | |
19 | if (IS_ERR(inner_map)) | |
20 | return inner_map; | |
21 | ||
56f668df MKL |
22 | /* Does not support >1 level map-in-map */ |
23 | if (inner_map->inner_map_meta) { | |
f73e601a KKD |
24 | ret = -EINVAL; |
25 | goto put; | |
56f668df MKL |
26 | } |
27 | ||
f4d05259 | 28 | if (!inner_map->ops->map_meta_equal) { |
f73e601a KKD |
29 | ret = -ENOTSUPP; |
30 | goto put; | |
f4d05259 MKL |
31 | } |
32 | ||
9d5564dd DB |
33 | inner_map_meta_size = sizeof(*inner_map_meta); |
34 | /* In some cases verifier needs to access beyond just base map. */ | |
9ee98229 | 35 | if (inner_map->ops == &array_map_ops || inner_map->ops == &percpu_array_map_ops) |
9d5564dd DB |
36 | inner_map_meta_size = sizeof(struct bpf_array); |
37 | ||
38 | inner_map_meta = kzalloc(inner_map_meta_size, GFP_USER); | |
56f668df | 39 | if (!inner_map_meta) { |
f73e601a KKD |
40 | ret = -ENOMEM; |
41 | goto put; | |
56f668df MKL |
42 | } |
43 | ||
44 | inner_map_meta->map_type = inner_map->map_type; | |
45 | inner_map_meta->key_size = inner_map->key_size; | |
46 | inner_map_meta->value_size = inner_map->value_size; | |
47 | inner_map_meta->map_flags = inner_map->map_flags; | |
56f668df | 48 | inner_map_meta->max_entries = inner_map->max_entries; |
f73e601a | 49 | |
aa3496ac KKD |
50 | inner_map_meta->record = btf_record_dup(inner_map->record); |
51 | if (IS_ERR(inner_map_meta->record)) { | |
52 | /* btf_record_dup returns NULL or valid pointer in case of | |
53 | * invalid/empty/valid, but ERR_PTR in case of errors. During | |
54 | * equality NULL or IS_ERR is equivalent. | |
55 | */ | |
f73e601a KKD |
56 | ret = PTR_ERR(inner_map_meta->record); |
57 | goto free; | |
58 | } | |
c22dfdd2 KKD |
59 | /* Note: We must use the same BTF, as we also used btf_record_dup above |
60 | * which relies on BTF being same for both maps, as some members like | |
61 | * record->fields.list_head have pointers like value_rec pointing into | |
62 | * inner_map->btf. | |
63 | */ | |
40ec00ab AS |
64 | if (inner_map->btf) { |
65 | btf_get(inner_map->btf); | |
66 | inner_map_meta->btf = inner_map->btf; | |
67 | } | |
56f668df | 68 | |
9d5564dd DB |
69 | /* Misc members not needed in bpf_map_meta_equal() check. */ |
70 | inner_map_meta->ops = inner_map->ops; | |
9ee98229 | 71 | if (inner_map->ops == &array_map_ops || inner_map->ops == &percpu_array_map_ops) { |
cba41bb7 RRE |
72 | struct bpf_array *inner_array_meta = |
73 | container_of(inner_map_meta, struct bpf_array, map); | |
74 | struct bpf_array *inner_array = container_of(inner_map, struct bpf_array, map); | |
75 | ||
76 | inner_array_meta->index_mask = inner_array->index_mask; | |
77 | inner_array_meta->elem_size = inner_array->elem_size; | |
2c78ee89 | 78 | inner_map_meta->bypass_spec_v1 = inner_map->bypass_spec_v1; |
9d5564dd DB |
79 | } |
80 | ||
56f668df MKL |
81 | fdput(f); |
82 | return inner_map_meta; | |
f73e601a KKD |
83 | free: |
84 | kfree(inner_map_meta); | |
85 | put: | |
86 | fdput(f); | |
87 | return ERR_PTR(ret); | |
56f668df MKL |
88 | } |
89 | ||
90 | void bpf_map_meta_free(struct bpf_map *map_meta) | |
91 | { | |
aa3496ac | 92 | bpf_map_free_record(map_meta); |
40ec00ab | 93 | btf_put(map_meta->btf); |
56f668df MKL |
94 | kfree(map_meta); |
95 | } | |
96 | ||
97 | bool bpf_map_meta_equal(const struct bpf_map *meta0, | |
98 | const struct bpf_map *meta1) | |
99 | { | |
100 | /* No need to compare ops because it is covered by map_type */ | |
101 | return meta0->map_type == meta1->map_type && | |
102 | meta0->key_size == meta1->key_size && | |
103 | meta0->value_size == meta1->value_size && | |
61df10c7 | 104 | meta0->map_flags == meta1->map_flags && |
aa3496ac | 105 | btf_record_equal(meta0->record, meta1->record); |
56f668df MKL |
106 | } |
107 | ||
108 | void *bpf_map_fd_get_ptr(struct bpf_map *map, | |
109 | struct file *map_file /* not used */, | |
110 | int ufd) | |
111 | { | |
f4d05259 | 112 | struct bpf_map *inner_map, *inner_map_meta; |
56f668df MKL |
113 | struct fd f; |
114 | ||
115 | f = fdget(ufd); | |
116 | inner_map = __bpf_map_get(f); | |
117 | if (IS_ERR(inner_map)) | |
118 | return inner_map; | |
119 | ||
f4d05259 MKL |
120 | inner_map_meta = map->inner_map_meta; |
121 | if (inner_map_meta->ops->map_meta_equal(inner_map_meta, inner_map)) | |
1e0bd5a0 | 122 | bpf_map_inc(inner_map); |
56f668df MKL |
123 | else |
124 | inner_map = ERR_PTR(-EINVAL); | |
125 | ||
126 | fdput(f); | |
127 | return inner_map; | |
128 | } | |
129 | ||
20c20bd1 | 130 | void bpf_map_fd_put_ptr(struct bpf_map *map, void *ptr, bool need_defer) |
56f668df | 131 | { |
87667336 HT |
132 | struct bpf_map *inner_map = ptr; |
133 | ||
af66bfd3 HT |
134 | /* Defer the freeing of inner map according to the sleepable attribute |
135 | * of bpf program which owns the outer map, so unnecessary waiting for | |
136 | * RCU tasks trace grace period can be avoided. | |
56f668df | 137 | */ |
af66bfd3 HT |
138 | if (need_defer) { |
139 | if (atomic64_read(&map->sleepable_refcnt)) | |
140 | WRITE_ONCE(inner_map->free_after_mult_rcu_gp, true); | |
141 | else | |
142 | WRITE_ONCE(inner_map->free_after_rcu_gp, true); | |
143 | } | |
87667336 | 144 | bpf_map_put(inner_map); |
56f668df | 145 | } |
14dc6f04 MKL |
146 | |
147 | u32 bpf_map_fd_sys_lookup_elem(void *ptr) | |
148 | { | |
149 | return ((struct bpf_map *)ptr)->id; | |
150 | } |