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 uint16_t magic; 13 uint8_t version; 14 uint8_t flags; 15 uint32_t hdr_len; 16 17 /* All offsets are in bytes relative to the end of this header */ 18 uint32_t type_off; /* offset of type section */ 19 uint32_t type_len; /* length of type section */ 20 uint32_t str_off; /* offset of string section */ 21 uint32_t 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 uint32_t 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 uint32_t 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 uint32_t size; 51 uint32_t 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 #define BTF_KIND_UNKN 0 /* Unknown */ 60 #define BTF_KIND_INT 1 /* Integer */ 61 #define BTF_KIND_PTR 2 /* Pointer */ 62 #define BTF_KIND_ARRAY 3 /* Array */ 63 #define BTF_KIND_STRUCT 4 /* Struct */ 64 #define BTF_KIND_UNION 5 /* Union */ 65 #define BTF_KIND_ENUM 6 /* Enumeration */ 66 #define BTF_KIND_FWD 7 /* Forward */ 67 #define BTF_KIND_TYPEDEF 8 /* Typedef */ 68 #define BTF_KIND_VOLATILE 9 /* Volatile */ 69 #define BTF_KIND_CONST 10 /* Const */ 70 #define BTF_KIND_RESTRICT 11 /* Restrict */ 71 #define BTF_KIND_FUNC 12 /* Function */ 72 #define BTF_KIND_FUNC_PROTO 13 /* Function Proto */ 73 #define BTF_KIND_VAR 14 /* Variable */ 74 #define BTF_KIND_DATASEC 15 /* Section */ 75 #define BTF_KIND_FLOAT 16 /* Floating point */ 76 #define BTF_KIND_MAX BTF_KIND_FLOAT 77 #define NR_BTF_KINDS (BTF_KIND_MAX + 1) 78 79 /* For some specific BTF_KIND, "struct btf_type" is immediately 80 * followed by extra data. 81 */ 82 83 /* BTF_KIND_INT is followed by a u32 and the following 84 * is the 32 bits arrangement: 85 */ 86 #define BTF_INT_ENCODING(VAL) (((VAL) & 0x0f000000) >> 24) 87 #define BTF_INT_OFFSET(VAL) (((VAL) & 0x00ff0000) >> 16) 88 #define BTF_INT_BITS(VAL) ((VAL) & 0x000000ff) 89 90 /* Attributes stored in the BTF_INT_ENCODING */ 91 #define BTF_INT_SIGNED (1 << 0) 92 #define BTF_INT_CHAR (1 << 1) 93 #define BTF_INT_BOOL (1 << 2) 94 95 /* BTF_KIND_ENUM is followed by multiple "struct btf_enum". 96 * The exact number of btf_enum is stored in the vlen (of the 97 * info in "struct btf_type"). 98 */ 99 struct btf_enum { 100 uint32_t name_off; 101 int32_t val; 102 }; 103 104 /* BTF_KIND_ARRAY is followed by one "struct btf_array" */ 105 struct btf_array { 106 uint32_t type; 107 uint32_t index_type; 108 uint32_t nelems; 109 }; 110 111 /* BTF_KIND_STRUCT and BTF_KIND_UNION are followed 112 * by multiple "struct btf_member". The exact number 113 * of btf_member is stored in the vlen (of the info in 114 * "struct btf_type"). 115 */ 116 struct btf_member { 117 uint32_t name_off; 118 uint32_t type; 119 /* If the type info kind_flag is set, the btf_member offset 120 * contains both member bitfield size and bit offset. The 121 * bitfield size is set for bitfield members. If the type 122 * info kind_flag is not set, the offset contains only bit 123 * offset. 124 */ 125 uint32_t offset; 126 }; 127 128 /* If the struct/union type info kind_flag is set, the 129 * following two macros are used to access bitfield_size 130 * and bit_offset from btf_member.offset. 131 */ 132 #define BTF_MEMBER_BITFIELD_SIZE(val) ((val) >> 24) 133 #define BTF_MEMBER_BIT_OFFSET(val) ((val) & 0xffffff) 134 135 /* BTF_KIND_FUNC_PROTO is followed by multiple "struct btf_param". 136 * The exact number of btf_param is stored in the vlen (of the 137 * info in "struct btf_type"). 138 */ 139 struct btf_param { 140 uint32_t name_off; 141 uint32_t type; 142 }; 143 144 enum { 145 BTF_VAR_STATIC = 0, 146 BTF_VAR_GLOBAL_ALLOCATED = 1, 147 BTF_VAR_GLOBAL_EXTERN = 2, 148 }; 149 150 enum btf_func_linkage { 151 BTF_FUNC_STATIC = 0, 152 BTF_FUNC_GLOBAL = 1, 153 BTF_FUNC_EXTERN = 2, 154 }; 155 156 /* BTF_KIND_VAR is followed by a single "struct btf_var" to describe 157 * additional information related to the variable such as its linkage. 158 */ 159 struct btf_var { 160 uint32_t linkage; 161 }; 162 163 /* BTF_KIND_DATASEC is followed by multiple "struct btf_var_secinfo" 164 * to describe all BTF_KIND_VAR types it contains along with it's 165 * in-section offset as well as size. 166 */ 167 struct btf_var_secinfo { 168 uint32_t type; 169 uint32_t offset; 170 uint32_t size; 171 }; 172 173 #endif /* _UAPI__LINUX_BTF_H__ */ 174