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 struct btf_header { 12 __u16 magic; 13 __u8 version; 14 __u8 flags; 15 __u32 hdr_len; 16 17 /* All offsets are in bytes relative to the end of this header */ 18 __u32 type_off; /* offset of type section */ 19 __u32 type_len; /* length of type section */ 20 __u32 str_off; /* offset of string section */ 21 __u32 str_len; /* length of string section */ 22 }; 23 24 /* Max # of type identifier */ 25 #define BTF_MAX_TYPE 0x000fffff 26 /* Max offset into the string section */ 27 #define BTF_MAX_NAME_OFFSET 0x00ffffff 28 /* Max # of struct/union/enum members or func args */ 29 #define BTF_MAX_VLEN 0xffff 30 31 struct btf_type { 32 __u32 name_off; 33 /* "info" bits arrangement 34 * bits 0-15: vlen (e.g. # of struct's members) 35 * bits 16-23: unused 36 * bits 24-27: kind (e.g. int, ptr, array...etc) 37 * bits 28-30: unused 38 * bit 31: kind_flag, currently used by 39 * struct, union and fwd 40 */ 41 __u32 info; 42 /* "size" is used by INT, ENUM, STRUCT, UNION and DATASEC. 43 * "size" tells the size of the type it is describing. 44 * 45 * "type" is used by PTR, TYPEDEF, VOLATILE, CONST, RESTRICT, 46 * FUNC, FUNC_PROTO and VAR. 47 * "type" is a type_id referring to another type. 48 */ 49 union { 50 __u32 size; 51 __u32 type; 52 }; 53 }; 54 55 #define BTF_INFO_KIND(info) (((info) >> 24) & 0x1f) 56 #define BTF_INFO_VLEN(info) ((info) & 0xffff) 57 #define BTF_INFO_KFLAG(info) ((info) >> 31) 58 59 enum { 60 BTF_KIND_UNKN = 0, /* Unknown */ 61 BTF_KIND_INT = 1, /* Integer */ 62 BTF_KIND_PTR = 2, /* Pointer */ 63 BTF_KIND_ARRAY = 3, /* Array */ 64 BTF_KIND_STRUCT = 4, /* Struct */ 65 BTF_KIND_UNION = 5, /* Union */ 66 BTF_KIND_ENUM = 6, /* Enumeration */ 67 BTF_KIND_FWD = 7, /* Forward */ 68 BTF_KIND_TYPEDEF = 8, /* Typedef */ 69 BTF_KIND_VOLATILE = 9, /* Volatile */ 70 BTF_KIND_CONST = 10, /* Const */ 71 BTF_KIND_RESTRICT = 11, /* Restrict */ 72 BTF_KIND_FUNC = 12, /* Function */ 73 BTF_KIND_FUNC_PROTO = 13, /* Function Proto */ 74 BTF_KIND_VAR = 14, /* Variable */ 75 BTF_KIND_DATASEC = 15, /* Section */ 76 BTF_KIND_FLOAT = 16, /* Floating point */ 77 78 NR_BTF_KINDS, 79 BTF_KIND_MAX = NR_BTF_KINDS - 1, 80 }; 81 82 /* For some specific BTF_KIND, "struct btf_type" is immediately 83 * followed by extra data. 84 */ 85 86 /* BTF_KIND_INT is followed by a u32 and the following 87 * is the 32 bits arrangement: 88 */ 89 #define BTF_INT_ENCODING(VAL) (((VAL) & 0x0f000000) >> 24) 90 #define BTF_INT_OFFSET(VAL) (((VAL) & 0x00ff0000) >> 16) 91 #define BTF_INT_BITS(VAL) ((VAL) & 0x000000ff) 92 93 /* Attributes stored in the BTF_INT_ENCODING */ 94 #define BTF_INT_SIGNED (1 << 0) 95 #define BTF_INT_CHAR (1 << 1) 96 #define BTF_INT_BOOL (1 << 2) 97 98 /* BTF_KIND_ENUM is followed by multiple "struct btf_enum". 99 * The exact number of btf_enum is stored in the vlen (of the 100 * info in "struct btf_type"). 101 */ 102 struct btf_enum { 103 __u32 name_off; 104 __s32 val; 105 }; 106 107 /* BTF_KIND_ARRAY is followed by one "struct btf_array" */ 108 struct btf_array { 109 __u32 type; 110 __u32 index_type; 111 __u32 nelems; 112 }; 113 114 /* BTF_KIND_STRUCT and BTF_KIND_UNION are followed 115 * by multiple "struct btf_member". The exact number 116 * of btf_member is stored in the vlen (of the info in 117 * "struct btf_type"). 118 */ 119 struct btf_member { 120 __u32 name_off; 121 __u32 type; 122 /* If the type info kind_flag is set, the btf_member offset 123 * contains both member bitfield size and bit offset. The 124 * bitfield size is set for bitfield members. If the type 125 * info kind_flag is not set, the offset contains only bit 126 * offset. 127 */ 128 __u32 offset; 129 }; 130 131 /* If the struct/union type info kind_flag is set, the 132 * following two macros are used to access bitfield_size 133 * and bit_offset from btf_member.offset. 134 */ 135 #define BTF_MEMBER_BITFIELD_SIZE(val) ((val) >> 24) 136 #define BTF_MEMBER_BIT_OFFSET(val) ((val) & 0xffffff) 137 138 /* BTF_KIND_FUNC_PROTO is followed by multiple "struct btf_param". 139 * The exact number of btf_param is stored in the vlen (of the 140 * info in "struct btf_type"). 141 */ 142 struct btf_param { 143 __u32 name_off; 144 __u32 type; 145 }; 146 147 enum { 148 BTF_VAR_STATIC = 0, 149 BTF_VAR_GLOBAL_ALLOCATED = 1, 150 BTF_VAR_GLOBAL_EXTERN = 2, 151 }; 152 153 enum btf_func_linkage { 154 BTF_FUNC_STATIC = 0, 155 BTF_FUNC_GLOBAL = 1, 156 BTF_FUNC_EXTERN = 2, 157 }; 158 159 /* BTF_KIND_VAR is followed by a single "struct btf_var" to describe 160 * additional information related to the variable such as its linkage. 161 */ 162 struct btf_var { 163 __u32 linkage; 164 }; 165 166 /* BTF_KIND_DATASEC is followed by multiple "struct btf_var_secinfo" 167 * to describe all BTF_KIND_VAR types it contains along with it's 168 * in-section offset as well as size. 169 */ 170 struct btf_var_secinfo { 171 __u32 type; 172 __u32 offset; 173 __u32 size; 174 }; 175 176 #endif /* _UAPI__LINUX_BTF_H__ */ 177