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