1 /* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */ 2 /* Copyright (c) 2018 Facebook */ 3 #ifndef _UAPI__LINUX_BTF_H__ 4 #define _UAPI__LINUX_BTF_H__ 5 6 #include <linux/types.h> 7 8 #define BTF_MAGIC 0xeB9F 9 #define BTF_VERSION 1 10 11 /* 12 * BTF layout section consists of a struct btf_layout for each known 13 * kind at BTF encoding time. 14 */ 15 struct btf_layout { 16 __u8 info_sz; /* size of singular element after btf_type */ 17 __u8 elem_sz; /* size of each of btf_vlen(t) elements */ 18 __u16 flags; /* currently unused */ 19 }; 20 21 struct btf_header { 22 __u16 magic; 23 __u8 version; 24 __u8 flags; 25 __u32 hdr_len; 26 27 /* All offsets are in bytes relative to the end of this header */ 28 __u32 type_off; /* offset of type section */ 29 __u32 type_len; /* length of type section */ 30 __u32 str_off; /* offset of string section */ 31 __u32 str_len; /* length of string section */ 32 __u32 layout_off; /* offset of layout section */ 33 __u32 layout_len; /* length of layout section */ 34 }; 35 36 enum btf_max { 37 /* Max possible kind */ 38 BTF_MAX_KIND = 0x0000007f, 39 /* Max # of type identifier */ 40 BTF_MAX_TYPE = 0x000fffff, 41 /* Max offset into the string section */ 42 BTF_MAX_NAME_OFFSET = 0x00ffffff, 43 /* Max # of struct/union/enum members or func args */ 44 BTF_MAX_VLEN = 0x00ffffff, 45 }; 46 47 struct btf_type { 48 __u32 name_off; 49 /* "info" bits arrangement 50 * bits 0-23: vlen (e.g. # of struct's members) 51 * bits 24-30: kind (e.g. int, ptr, array...etc) 52 * bit 31: kind_flag, currently used by 53 * struct, union, enum, fwd, enum64, 54 * decl_tag and type_tag 55 */ 56 __u32 info; 57 /* "size" is used by INT, ENUM, STRUCT, UNION, DATASEC and ENUM64. 58 * "size" tells the size of the type it is describing. 59 * 60 * "type" is used by PTR, TYPEDEF, VOLATILE, CONST, RESTRICT, 61 * FUNC, FUNC_PROTO, VAR, DECL_TAG and TYPE_TAG. 62 * "type" is a type_id referring to another type. 63 */ 64 union { 65 __u32 size; 66 __u32 type; 67 }; 68 }; 69 70 #define BTF_INFO_KIND(info) (((info) >> 24) & 0x7f) 71 #define BTF_INFO_VLEN(info) ((info) & 0xffffff) 72 #define BTF_INFO_KFLAG(info) ((info) >> 31) 73 74 enum { 75 BTF_KIND_UNKN = 0, /* Unknown */ 76 BTF_KIND_INT = 1, /* Integer */ 77 BTF_KIND_PTR = 2, /* Pointer */ 78 BTF_KIND_ARRAY = 3, /* Array */ 79 BTF_KIND_STRUCT = 4, /* Struct */ 80 BTF_KIND_UNION = 5, /* Union */ 81 BTF_KIND_ENUM = 6, /* Enumeration up to 32-bit values */ 82 BTF_KIND_FWD = 7, /* Forward */ 83 BTF_KIND_TYPEDEF = 8, /* Typedef */ 84 BTF_KIND_VOLATILE = 9, /* Volatile */ 85 BTF_KIND_CONST = 10, /* Const */ 86 BTF_KIND_RESTRICT = 11, /* Restrict */ 87 BTF_KIND_FUNC = 12, /* Function */ 88 BTF_KIND_FUNC_PROTO = 13, /* Function Proto */ 89 BTF_KIND_VAR = 14, /* Variable */ 90 BTF_KIND_DATASEC = 15, /* Section */ 91 BTF_KIND_FLOAT = 16, /* Floating point */ 92 BTF_KIND_DECL_TAG = 17, /* Decl Tag */ 93 BTF_KIND_TYPE_TAG = 18, /* Type Tag */ 94 BTF_KIND_ENUM64 = 19, /* Enumeration up to 64-bit values */ 95 96 NR_BTF_KINDS, 97 BTF_KIND_MAX = NR_BTF_KINDS - 1, 98 }; 99 100 /* For some specific BTF_KIND, "struct btf_type" is immediately 101 * followed by extra data. 102 */ 103 104 /* BTF_KIND_INT is followed by a u32 and the following 105 * is the 32 bits arrangement: 106 */ 107 #define BTF_INT_ENCODING(VAL) (((VAL) & 0x0f000000) >> 24) 108 #define BTF_INT_OFFSET(VAL) (((VAL) & 0x00ff0000) >> 16) 109 #define BTF_INT_BITS(VAL) ((VAL) & 0x000000ff) 110 111 /* Attributes stored in the BTF_INT_ENCODING */ 112 #define BTF_INT_SIGNED (1 << 0) 113 #define BTF_INT_CHAR (1 << 1) 114 #define BTF_INT_BOOL (1 << 2) 115 116 /* BTF_KIND_ENUM is followed by multiple "struct btf_enum". 117 * The exact number of btf_enum is stored in the vlen (of the 118 * info in "struct btf_type"). 119 */ 120 struct btf_enum { 121 __u32 name_off; 122 __s32 val; 123 }; 124 125 /* BTF_KIND_ARRAY is followed by one "struct btf_array" */ 126 struct btf_array { 127 __u32 type; 128 __u32 index_type; 129 __u32 nelems; 130 }; 131 132 /* BTF_KIND_STRUCT and BTF_KIND_UNION are followed 133 * by multiple "struct btf_member". The exact number 134 * of btf_member is stored in the vlen (of the info in 135 * "struct btf_type"). 136 */ 137 struct btf_member { 138 __u32 name_off; 139 __u32 type; 140 /* If the type info kind_flag is set, the btf_member offset 141 * contains both member bitfield size and bit offset. The 142 * bitfield size is set for bitfield members. If the type 143 * info kind_flag is not set, the offset contains only bit 144 * offset. 145 */ 146 __u32 offset; 147 }; 148 149 /* If the struct/union type info kind_flag is set, the 150 * following two macros are used to access bitfield_size 151 * and bit_offset from btf_member.offset. 152 */ 153 #define BTF_MEMBER_BITFIELD_SIZE(val) ((val) >> 24) 154 #define BTF_MEMBER_BIT_OFFSET(val) ((val) & 0xffffff) 155 156 /* BTF_KIND_FUNC_PROTO is followed by multiple "struct btf_param". 157 * The exact number of btf_param is stored in the vlen (of the 158 * info in "struct btf_type"). 159 */ 160 struct btf_param { 161 __u32 name_off; 162 __u32 type; 163 }; 164 165 enum { 166 BTF_VAR_STATIC = 0, 167 BTF_VAR_GLOBAL_ALLOCATED = 1, 168 BTF_VAR_GLOBAL_EXTERN = 2, 169 }; 170 171 enum btf_func_linkage { 172 BTF_FUNC_STATIC = 0, 173 BTF_FUNC_GLOBAL = 1, 174 BTF_FUNC_EXTERN = 2, 175 }; 176 177 /* BTF_KIND_VAR is followed by a single "struct btf_var" to describe 178 * additional information related to the variable such as its linkage. 179 */ 180 struct btf_var { 181 __u32 linkage; 182 }; 183 184 /* BTF_KIND_DATASEC is followed by multiple "struct btf_var_secinfo" 185 * to describe all BTF_KIND_VAR types it contains along with it's 186 * in-section offset as well as size. 187 */ 188 struct btf_var_secinfo { 189 __u32 type; 190 __u32 offset; 191 __u32 size; 192 }; 193 194 /* BTF_KIND_DECL_TAG is followed by a single "struct btf_decl_tag" to describe 195 * additional information related to the tag applied location. 196 * If component_idx == -1, the tag is applied to a struct, union, 197 * variable or function. Otherwise, it is applied to a struct/union 198 * member or a func argument, and component_idx indicates which member 199 * or argument (0 ... vlen-1). 200 */ 201 struct btf_decl_tag { 202 __s32 component_idx; 203 }; 204 205 /* BTF_KIND_ENUM64 is followed by multiple "struct btf_enum64". 206 * The exact number of btf_enum64 is stored in the vlen (of the 207 * info in "struct btf_type"). 208 */ 209 struct btf_enum64 { 210 __u32 name_off; 211 __u32 val_lo32; 212 __u32 val_hi32; 213 }; 214 215 #endif /* _UAPI__LINUX_BTF_H__ */ 216