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++) 117 118 static inline bool btf_type_is_ptr(const struct btf_type *t) 119 { 120 return BTF_INFO_KIND(t->info) == BTF_KIND_PTR; 121 } 122 123 static inline bool btf_type_is_int(const struct btf_type *t) 124 { 125 return BTF_INFO_KIND(t->info) == BTF_KIND_INT; 126 } 127 128 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 } 132 133 static inline bool btf_type_is_enum(const struct btf_type *t) 134 { 135 return BTF_INFO_KIND(t->info) == BTF_KIND_ENUM; 136 } 137 138 static inline bool btf_type_is_typedef(const struct btf_type *t) 139 { 140 return BTF_INFO_KIND(t->info) == BTF_KIND_TYPEDEF; 141 } 142 143 static inline bool btf_type_is_func(const struct btf_type *t) 144 { 145 return BTF_INFO_KIND(t->info) == BTF_KIND_FUNC; 146 } 147 148 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 } 152 153 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 */ 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 } 167 168 static inline u16 btf_type_vlen(const struct btf_type *t) 169 { 170 return BTF_INFO_VLEN(t->info); 171 } 172 173 static inline u16 btf_func_linkage(const struct btf_type *t) 174 { 175 return BTF_INFO_VLEN(t->info); 176 } 177 178 static inline bool btf_type_kflag(const struct btf_type *t) 179 { 180 return BTF_INFO_KFLAG(t->info); 181 } 182 183 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 } 189 190 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 } 196 197 static inline const struct btf_member *btf_type_member(const struct btf_type *t) 198 { 199 return (const struct btf_member *)(t + 1); 200 } 201 202 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 214 static inline const struct btf_type *btf_type_by_id(const struct btf *btf, 215 u32 type_id) 216 { 217 return NULL; 218 } 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