1 /* SPDX-License-Identifier: GPL-2.0 */
2 /* Copyright (c) 2018 Facebook */
3
4 #ifndef _LINUX_BTF_H
5 #define _LINUX_BTF_H 1
6
7 #include <linux/types.h>
8 #include <uapi/linux/btf.h>
9 #include <uapi/linux/bpf.h>
10
11 #define BTF_TYPE_EMIT(type) ((void)(type *)0)
12
13 struct btf;
14 struct btf_member;
15 struct btf_type;
16 union bpf_attr;
17 struct btf_show;
18
19 extern const struct file_operations btf_fops;
20
21 void btf_put(struct btf *btf);
22 int btf_new_fd(const union bpf_attr *attr);
23 struct btf *btf_get_by_fd(int fd);
24 int btf_get_info_by_fd(const struct btf *btf,
25 const union bpf_attr *attr,
26 union bpf_attr __user *uattr);
27 /* Figure out the size of a type_id. If type_id is a modifier
28 * (e.g. const), it will be resolved to find out the type with size.
29 *
30 * For example:
31 * In describing "const void *", type_id is "const" and "const"
32 * refers to "void *". The return type will be "void *".
33 *
34 * If type_id is a simple "int", then return type will be "int".
35 *
36 * @btf: struct btf object
37 * @type_id: Find out the size of type_id. The type_id of the return
38 * type is set to *type_id.
39 * @ret_size: It can be NULL. If not NULL, the size of the return
40 * type is set to *ret_size.
41 * Return: The btf_type (resolved to another type with size info if needed).
42 * NULL is returned if type_id itself does not have size info
43 * (e.g. void) or it cannot be resolved to another type that
44 * has size info.
45 * *type_id and *ret_size will not be changed in the
46 * NULL return case.
47 */
48 const struct btf_type *btf_type_id_size(const struct btf *btf,
49 u32 *type_id,
50 u32 *ret_size);
51
52 /*
53 * Options to control show behaviour.
54 * - BTF_SHOW_COMPACT: no formatting around type information
55 * - BTF_SHOW_NONAME: no struct/union member names/types
56 * - BTF_SHOW_PTR_RAW: show raw (unobfuscated) pointer values;
57 * equivalent to %px.
58 * - BTF_SHOW_ZERO: show zero-valued struct/union members; they
59 * are not displayed by default
60 * - BTF_SHOW_UNSAFE: skip use of bpf_probe_read() to safely read
61 * data before displaying it.
62 */
63 #define BTF_SHOW_COMPACT BTF_F_COMPACT
64 #define BTF_SHOW_NONAME BTF_F_NONAME
65 #define BTF_SHOW_PTR_RAW BTF_F_PTR_RAW
66 #define BTF_SHOW_ZERO BTF_F_ZERO
67 #define BTF_SHOW_UNSAFE (1ULL << 4)
68
69 void btf_type_seq_show(const struct btf *btf, u32 type_id, void *obj,
70 struct seq_file *m);
71 int btf_type_seq_show_flags(const struct btf *btf, u32 type_id, void *obj,
72 struct seq_file *m, u64 flags);
73
74 /*
75 * Copy len bytes of string representation of obj of BTF type_id into buf.
76 *
77 * @btf: struct btf object
78 * @type_id: type id of type obj points to
79 * @obj: pointer to typed data
80 * @buf: buffer to write to
81 * @len: maximum length to write to buf
82 * @flags: show options (see above)
83 *
84 * Return: length that would have been/was copied as per snprintf, or
85 * negative error.
86 */
87 int btf_type_snprintf_show(const struct btf *btf, u32 type_id, void *obj,
88 char *buf, int len, u64 flags);
89
90 int btf_get_fd_by_id(u32 id);
91 u32 btf_id(const struct btf *btf);
92 bool btf_member_is_reg_int(const struct btf *btf, const struct btf_type *s,
93 const struct btf_member *m,
94 u32 expected_offset, u32 expected_size);
95 int btf_find_spin_lock(const struct btf *btf, const struct btf_type *t);
96 bool btf_type_is_void(const struct btf_type *t);
97 s32 btf_find_by_name_kind(const struct btf *btf, const char *name, u8 kind);
98 const struct btf_type *btf_type_skip_modifiers(const struct btf *btf,
99 u32 id, u32 *res_id);
100 const struct btf_type *btf_type_resolve_ptr(const struct btf *btf,
101 u32 id, u32 *res_id);
102 const struct btf_type *btf_type_resolve_func_ptr(const struct btf *btf,
103 u32 id, u32 *res_id);
104 const struct btf_type *
105 btf_resolve_size(const struct btf *btf, const struct btf_type *type,
106 u32 *type_size);
107
108 #define for_each_member(i, struct_type, member) \
109 for (i = 0, member = btf_type_member(struct_type); \
110 i < btf_type_vlen(struct_type); \
111 i++, member++)
112
113 #define for_each_vsi(i, datasec_type, member) \
114 for (i = 0, member = btf_type_var_secinfo(datasec_type); \
115 i < btf_type_vlen(datasec_type); \
116 i++, member++)
117
btf_type_is_ptr(const struct btf_type * t)118 static inline bool btf_type_is_ptr(const struct btf_type *t)
119 {
120 return BTF_INFO_KIND(t->info) == BTF_KIND_PTR;
121 }
122
btf_type_is_int(const struct btf_type * t)123 static inline bool btf_type_is_int(const struct btf_type *t)
124 {
125 return BTF_INFO_KIND(t->info) == BTF_KIND_INT;
126 }
127
btf_type_is_small_int(const struct btf_type * t)128 static inline bool btf_type_is_small_int(const struct btf_type *t)
129 {
130 return btf_type_is_int(t) && t->size <= sizeof(u64);
131 }
132
btf_type_is_enum(const struct btf_type * t)133 static inline bool btf_type_is_enum(const struct btf_type *t)
134 {
135 return BTF_INFO_KIND(t->info) == BTF_KIND_ENUM;
136 }
137
btf_type_is_typedef(const struct btf_type * t)138 static inline bool btf_type_is_typedef(const struct btf_type *t)
139 {
140 return BTF_INFO_KIND(t->info) == BTF_KIND_TYPEDEF;
141 }
142
btf_type_is_func(const struct btf_type * t)143 static inline bool btf_type_is_func(const struct btf_type *t)
144 {
145 return BTF_INFO_KIND(t->info) == BTF_KIND_FUNC;
146 }
147
btf_type_is_func_proto(const struct btf_type * t)148 static inline bool btf_type_is_func_proto(const struct btf_type *t)
149 {
150 return BTF_INFO_KIND(t->info) == BTF_KIND_FUNC_PROTO;
151 }
152
btf_type_is_var(const struct btf_type * t)153 static inline bool btf_type_is_var(const struct btf_type *t)
154 {
155 return BTF_INFO_KIND(t->info) == BTF_KIND_VAR;
156 }
157
158 /* union is only a special case of struct:
159 * all its offsetof(member) == 0
160 */
btf_type_is_struct(const struct btf_type * t)161 static inline bool btf_type_is_struct(const struct btf_type *t)
162 {
163 u8 kind = BTF_INFO_KIND(t->info);
164
165 return kind == BTF_KIND_STRUCT || kind == BTF_KIND_UNION;
166 }
167
btf_type_vlen(const struct btf_type * t)168 static inline u16 btf_type_vlen(const struct btf_type *t)
169 {
170 return BTF_INFO_VLEN(t->info);
171 }
172
btf_func_linkage(const struct btf_type * t)173 static inline u16 btf_func_linkage(const struct btf_type *t)
174 {
175 return BTF_INFO_VLEN(t->info);
176 }
177
btf_type_kflag(const struct btf_type * t)178 static inline bool btf_type_kflag(const struct btf_type *t)
179 {
180 return BTF_INFO_KFLAG(t->info);
181 }
182
btf_member_bit_offset(const struct btf_type * struct_type,const struct btf_member * member)183 static inline u32 btf_member_bit_offset(const struct btf_type *struct_type,
184 const struct btf_member *member)
185 {
186 return btf_type_kflag(struct_type) ? BTF_MEMBER_BIT_OFFSET(member->offset)
187 : member->offset;
188 }
189
btf_member_bitfield_size(const struct btf_type * struct_type,const struct btf_member * member)190 static inline u32 btf_member_bitfield_size(const struct btf_type *struct_type,
191 const struct btf_member *member)
192 {
193 return btf_type_kflag(struct_type) ? BTF_MEMBER_BITFIELD_SIZE(member->offset)
194 : 0;
195 }
196
btf_type_member(const struct btf_type * t)197 static inline const struct btf_member *btf_type_member(const struct btf_type *t)
198 {
199 return (const struct btf_member *)(t + 1);
200 }
201
btf_type_var_secinfo(const struct btf_type * t)202 static inline const struct btf_var_secinfo *btf_type_var_secinfo(
203 const struct btf_type *t)
204 {
205 return (const struct btf_var_secinfo *)(t + 1);
206 }
207
208 #ifdef CONFIG_BPF_SYSCALL
209 const struct btf_type *btf_type_by_id(const struct btf *btf, u32 type_id);
210 const char *btf_name_by_offset(const struct btf *btf, u32 offset);
211 struct btf *btf_parse_vmlinux(void);
212 struct btf *bpf_prog_get_target_btf(const struct bpf_prog *prog);
213 #else
btf_type_by_id(const struct btf * btf,u32 type_id)214 static inline const struct btf_type *btf_type_by_id(const struct btf *btf,
215 u32 type_id)
216 {
217 return NULL;
218 }
btf_name_by_offset(const struct btf * btf,u32 offset)219 static inline const char *btf_name_by_offset(const struct btf *btf,
220 u32 offset)
221 {
222 return NULL;
223 }
224 #endif
225
226 #endif
227