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 #define BTF_TYPE_EMIT_ENUM(enum_val) ((void)enum_val) 13 14 struct btf; 15 struct btf_member; 16 struct btf_type; 17 union bpf_attr; 18 struct btf_show; 19 20 extern const struct file_operations btf_fops; 21 22 void btf_get(struct btf *btf); 23 void btf_put(struct btf *btf); 24 int btf_new_fd(const union bpf_attr *attr); 25 struct btf *btf_get_by_fd(int fd); 26 int btf_get_info_by_fd(const struct btf *btf, 27 const union bpf_attr *attr, 28 union bpf_attr __user *uattr); 29 /* Figure out the size of a type_id. If type_id is a modifier 30 * (e.g. const), it will be resolved to find out the type with size. 31 * 32 * For example: 33 * In describing "const void *", type_id is "const" and "const" 34 * refers to "void *". The return type will be "void *". 35 * 36 * If type_id is a simple "int", then return type will be "int". 37 * 38 * @btf: struct btf object 39 * @type_id: Find out the size of type_id. The type_id of the return 40 * type is set to *type_id. 41 * @ret_size: It can be NULL. If not NULL, the size of the return 42 * type is set to *ret_size. 43 * Return: The btf_type (resolved to another type with size info if needed). 44 * NULL is returned if type_id itself does not have size info 45 * (e.g. void) or it cannot be resolved to another type that 46 * has size info. 47 * *type_id and *ret_size will not be changed in the 48 * NULL return case. 49 */ 50 const struct btf_type *btf_type_id_size(const struct btf *btf, 51 u32 *type_id, 52 u32 *ret_size); 53 54 /* 55 * Options to control show behaviour. 56 * - BTF_SHOW_COMPACT: no formatting around type information 57 * - BTF_SHOW_NONAME: no struct/union member names/types 58 * - BTF_SHOW_PTR_RAW: show raw (unobfuscated) pointer values; 59 * equivalent to %px. 60 * - BTF_SHOW_ZERO: show zero-valued struct/union members; they 61 * are not displayed by default 62 * - BTF_SHOW_UNSAFE: skip use of bpf_probe_read() to safely read 63 * data before displaying it. 64 */ 65 #define BTF_SHOW_COMPACT BTF_F_COMPACT 66 #define BTF_SHOW_NONAME BTF_F_NONAME 67 #define BTF_SHOW_PTR_RAW BTF_F_PTR_RAW 68 #define BTF_SHOW_ZERO BTF_F_ZERO 69 #define BTF_SHOW_UNSAFE (1ULL << 4) 70 71 void btf_type_seq_show(const struct btf *btf, u32 type_id, void *obj, 72 struct seq_file *m); 73 int btf_type_seq_show_flags(const struct btf *btf, u32 type_id, void *obj, 74 struct seq_file *m, u64 flags); 75 76 /* 77 * Copy len bytes of string representation of obj of BTF type_id into buf. 78 * 79 * @btf: struct btf object 80 * @type_id: type id of type obj points to 81 * @obj: pointer to typed data 82 * @buf: buffer to write to 83 * @len: maximum length to write to buf 84 * @flags: show options (see above) 85 * 86 * Return: length that would have been/was copied as per snprintf, or 87 * negative error. 88 */ 89 int btf_type_snprintf_show(const struct btf *btf, u32 type_id, void *obj, 90 char *buf, int len, u64 flags); 91 92 int btf_get_fd_by_id(u32 id); 93 u32 btf_obj_id(const struct btf *btf); 94 bool btf_is_kernel(const struct btf *btf); 95 bool btf_is_module(const struct btf *btf); 96 struct module *btf_try_get_module(const struct btf *btf); 97 u32 btf_nr_types(const struct btf *btf); 98 bool btf_member_is_reg_int(const struct btf *btf, const struct btf_type *s, 99 const struct btf_member *m, 100 u32 expected_offset, u32 expected_size); 101 int btf_find_spin_lock(const struct btf *btf, const struct btf_type *t); 102 bool btf_type_is_void(const struct btf_type *t); 103 s32 btf_find_by_name_kind(const struct btf *btf, const char *name, u8 kind); 104 const struct btf_type *btf_type_skip_modifiers(const struct btf *btf, 105 u32 id, u32 *res_id); 106 const struct btf_type *btf_type_resolve_ptr(const struct btf *btf, 107 u32 id, u32 *res_id); 108 const struct btf_type *btf_type_resolve_func_ptr(const struct btf *btf, 109 u32 id, u32 *res_id); 110 const struct btf_type * 111 btf_resolve_size(const struct btf *btf, const struct btf_type *type, 112 u32 *type_size); 113 const char *btf_type_str(const struct btf_type *t); 114 115 #define for_each_member(i, struct_type, member) \ 116 for (i = 0, member = btf_type_member(struct_type); \ 117 i < btf_type_vlen(struct_type); \ 118 i++, member++) 119 120 #define for_each_vsi(i, datasec_type, member) \ 121 for (i = 0, member = btf_type_var_secinfo(datasec_type); \ 122 i < btf_type_vlen(datasec_type); \ 123 i++, member++) 124 125 static inline bool btf_type_is_ptr(const struct btf_type *t) 126 { 127 return BTF_INFO_KIND(t->info) == BTF_KIND_PTR; 128 } 129 130 static inline bool btf_type_is_int(const struct btf_type *t) 131 { 132 return BTF_INFO_KIND(t->info) == BTF_KIND_INT; 133 } 134 135 static inline bool btf_type_is_small_int(const struct btf_type *t) 136 { 137 return btf_type_is_int(t) && t->size <= sizeof(u64); 138 } 139 140 static inline bool btf_type_is_enum(const struct btf_type *t) 141 { 142 return BTF_INFO_KIND(t->info) == BTF_KIND_ENUM; 143 } 144 145 static inline bool btf_type_is_scalar(const struct btf_type *t) 146 { 147 return btf_type_is_int(t) || btf_type_is_enum(t); 148 } 149 150 static inline bool btf_type_is_typedef(const struct btf_type *t) 151 { 152 return BTF_INFO_KIND(t->info) == BTF_KIND_TYPEDEF; 153 } 154 155 static inline bool btf_type_is_func(const struct btf_type *t) 156 { 157 return BTF_INFO_KIND(t->info) == BTF_KIND_FUNC; 158 } 159 160 static inline bool btf_type_is_func_proto(const struct btf_type *t) 161 { 162 return BTF_INFO_KIND(t->info) == BTF_KIND_FUNC_PROTO; 163 } 164 165 static inline bool btf_type_is_var(const struct btf_type *t) 166 { 167 return BTF_INFO_KIND(t->info) == BTF_KIND_VAR; 168 } 169 170 /* union is only a special case of struct: 171 * all its offsetof(member) == 0 172 */ 173 static inline bool btf_type_is_struct(const struct btf_type *t) 174 { 175 u8 kind = BTF_INFO_KIND(t->info); 176 177 return kind == BTF_KIND_STRUCT || kind == BTF_KIND_UNION; 178 } 179 180 static inline u16 btf_type_vlen(const struct btf_type *t) 181 { 182 return BTF_INFO_VLEN(t->info); 183 } 184 185 static inline u16 btf_func_linkage(const struct btf_type *t) 186 { 187 return BTF_INFO_VLEN(t->info); 188 } 189 190 static inline bool btf_type_kflag(const struct btf_type *t) 191 { 192 return BTF_INFO_KFLAG(t->info); 193 } 194 195 static inline u32 btf_member_bit_offset(const struct btf_type *struct_type, 196 const struct btf_member *member) 197 { 198 return btf_type_kflag(struct_type) ? BTF_MEMBER_BIT_OFFSET(member->offset) 199 : member->offset; 200 } 201 202 static inline u32 btf_member_bitfield_size(const struct btf_type *struct_type, 203 const struct btf_member *member) 204 { 205 return btf_type_kflag(struct_type) ? BTF_MEMBER_BITFIELD_SIZE(member->offset) 206 : 0; 207 } 208 209 static inline const struct btf_member *btf_type_member(const struct btf_type *t) 210 { 211 return (const struct btf_member *)(t + 1); 212 } 213 214 static inline const struct btf_var_secinfo *btf_type_var_secinfo( 215 const struct btf_type *t) 216 { 217 return (const struct btf_var_secinfo *)(t + 1); 218 } 219 220 #ifdef CONFIG_BPF_SYSCALL 221 struct bpf_prog; 222 223 const struct btf_type *btf_type_by_id(const struct btf *btf, u32 type_id); 224 const char *btf_name_by_offset(const struct btf *btf, u32 offset); 225 struct btf *btf_parse_vmlinux(void); 226 struct btf *bpf_prog_get_target_btf(const struct bpf_prog *prog); 227 #else 228 static inline const struct btf_type *btf_type_by_id(const struct btf *btf, 229 u32 type_id) 230 { 231 return NULL; 232 } 233 static inline const char *btf_name_by_offset(const struct btf *btf, 234 u32 offset) 235 { 236 return NULL; 237 } 238 #endif 239 240 #endif 241