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 /* Max # of type identifier */ 37 #define BTF_MAX_TYPE 0x000fffff 38 /* Max offset into the string section */ 39 #define BTF_MAX_NAME_OFFSET 0x00ffffff 40 /* Max # of struct/union/enum members or func args */ 41 #define BTF_MAX_VLEN 0xffff 42 43 struct btf_type { 44 __u32 name_off; 45 /* "info" bits arrangement 46 * bits 0-15: vlen (e.g. # of struct's members) 47 * bits 16-23: unused 48 * bits 24-28: kind (e.g. int, ptr, array...etc) 49 * bits 29-30: unused 50 * bit 31: kind_flag, currently used by 51 * struct, union, enum, fwd, enum64, 52 * decl_tag and type_tag 53 */ 54 __u32 info; 55 /* "size" is used by INT, ENUM, STRUCT, UNION, DATASEC and ENUM64. 56 * "size" tells the size of the type it is describing. 57 * 58 * "type" is used by PTR, TYPEDEF, VOLATILE, CONST, RESTRICT, 59 * FUNC, FUNC_PROTO, VAR, DECL_TAG and TYPE_TAG. 60 * "type" is a type_id referring to another type. 61 */ 62 union { 63 __u32 size; 64 __u32 type; 65 }; 66 }; 67 68 #define BTF_INFO_KIND(info) (((info) >> 24) & 0x1f) 69 #define BTF_INFO_VLEN(info) ((info) & 0xffff) 70 #define BTF_INFO_KFLAG(info) ((info) >> 31) 71 72 enum { 73 BTF_KIND_UNKN = 0, /* Unknown */ 74 BTF_KIND_INT = 1, /* Integer */ 75 BTF_KIND_PTR = 2, /* Pointer */ 76 BTF_KIND_ARRAY = 3, /* Array */ 77 BTF_KIND_STRUCT = 4, /* Struct */ 78 BTF_KIND_UNION = 5, /* Union */ 79 BTF_KIND_ENUM = 6, /* Enumeration up to 32-bit values */ 80 BTF_KIND_FWD = 7, /* Forward */ 81 BTF_KIND_TYPEDEF = 8, /* Typedef */ 82 BTF_KIND_VOLATILE = 9, /* Volatile */ 83 BTF_KIND_CONST = 10, /* Const */ 84 BTF_KIND_RESTRICT = 11, /* Restrict */ 85 BTF_KIND_FUNC = 12, /* Function */ 86 BTF_KIND_FUNC_PROTO = 13, /* Function Proto */ 87 BTF_KIND_VAR = 14, /* Variable */ 88 BTF_KIND_DATASEC = 15, /* Section */ 89 BTF_KIND_FLOAT = 16, /* Floating point */ 90 BTF_KIND_DECL_TAG = 17, /* Decl Tag */ 91 BTF_KIND_TYPE_TAG = 18, /* Type Tag */ 92 BTF_KIND_ENUM64 = 19, /* Enumeration up to 64-bit values */ 93 94 NR_BTF_KINDS, 95 BTF_KIND_MAX = NR_BTF_KINDS - 1, 96 }; 97 98 /* For some specific BTF_KIND, "struct btf_type" is immediately 99 * followed by extra data. 100 */ 101 102 /* BTF_KIND_INT is followed by a u32 and the following 103 * is the 32 bits arrangement: 104 */ 105 #define BTF_INT_ENCODING(VAL) (((VAL) & 0x0f000000) >> 24) 106 #define BTF_INT_OFFSET(VAL) (((VAL) & 0x00ff0000) >> 16) 107 #define BTF_INT_BITS(VAL) ((VAL) & 0x000000ff) 108 109 /* Attributes stored in the BTF_INT_ENCODING */ 110 #define BTF_INT_SIGNED (1 << 0) 111 #define BTF_INT_CHAR (1 << 1) 112 #define BTF_INT_BOOL (1 << 2) 113 114 /* BTF_KIND_ENUM is followed by multiple "struct btf_enum". 115 * The exact number of btf_enum is stored in the vlen (of the 116 * info in "struct btf_type"). 117 */ 118 struct btf_enum { 119 __u32 name_off; 120 __s32 val; 121 }; 122 123 /* BTF_KIND_ARRAY is followed by one "struct btf_array" */ 124 struct btf_array { 125 __u32 type; 126 __u32 index_type; 127 __u32 nelems; 128 }; 129 130 /* BTF_KIND_STRUCT and BTF_KIND_UNION are followed 131 * by multiple "struct btf_member". The exact number 132 * of btf_member is stored in the vlen (of the info in 133 * "struct btf_type"). 134 */ 135 struct btf_member { 136 __u32 name_off; 137 __u32 type; 138 /* If the type info kind_flag is set, the btf_member offset 139 * contains both member bitfield size and bit offset. The 140 * bitfield size is set for bitfield members. If the type 141 * info kind_flag is not set, the offset contains only bit 142 * offset. 143 */ 144 __u32 offset; 145 }; 146 147 /* If the struct/union type info kind_flag is set, the 148 * following two macros are used to access bitfield_size 149 * and bit_offset from btf_member.offset. 150 */ 151 #define BTF_MEMBER_BITFIELD_SIZE(val) ((val) >> 24) 152 #define BTF_MEMBER_BIT_OFFSET(val) ((val) & 0xffffff) 153 154 /* BTF_KIND_FUNC_PROTO is followed by multiple "struct btf_param". 155 * The exact number of btf_param is stored in the vlen (of the 156 * info in "struct btf_type"). 157 */ 158 struct btf_param { 159 __u32 name_off; 160 __u32 type; 161 }; 162 163 enum { 164 BTF_VAR_STATIC = 0, 165 BTF_VAR_GLOBAL_ALLOCATED = 1, 166 BTF_VAR_GLOBAL_EXTERN = 2, 167 }; 168 169 enum btf_func_linkage { 170 BTF_FUNC_STATIC = 0, 171 BTF_FUNC_GLOBAL = 1, 172 BTF_FUNC_EXTERN = 2, 173 }; 174 175 /* BTF_KIND_VAR is followed by a single "struct btf_var" to describe 176 * additional information related to the variable such as its linkage. 177 */ 178 struct btf_var { 179 __u32 linkage; 180 }; 181 182 /* BTF_KIND_DATASEC is followed by multiple "struct btf_var_secinfo" 183 * to describe all BTF_KIND_VAR types it contains along with it's 184 * in-section offset as well as size. 185 */ 186 struct btf_var_secinfo { 187 __u32 type; 188 __u32 offset; 189 __u32 size; 190 }; 191 192 /* BTF_KIND_DECL_TAG is followed by a single "struct btf_decl_tag" to describe 193 * additional information related to the tag applied location. 194 * If component_idx == -1, the tag is applied to a struct, union, 195 * variable or function. Otherwise, it is applied to a struct/union 196 * member or a func argument, and component_idx indicates which member 197 * or argument (0 ... vlen-1). 198 */ 199 struct btf_decl_tag { 200 __s32 component_idx; 201 }; 202 203 /* BTF_KIND_ENUM64 is followed by multiple "struct btf_enum64". 204 * The exact number of btf_enum64 is stored in the vlen (of the 205 * info in "struct btf_type"). 206 */ 207 struct btf_enum64 { 208 __u32 name_off; 209 __u32 val_lo32; 210 __u32 val_hi32; 211 }; 212 213 #endif /* _UAPI__LINUX_BTF_H__ */ 214