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) & 0x0f) 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_MAX BTF_KIND_DATASEC 76 #define NR_BTF_KINDS (BTF_KIND_MAX + 1) 77 78 /* For some specific BTF_KIND, "struct btf_type" is immediately 79 * followed by extra data. 80 */ 81 82 /* BTF_KIND_INT is followed by a u32 and the following 83 * is the 32 bits arrangement: 84 */ 85 #define BTF_INT_ENCODING(VAL) (((VAL) & 0x0f000000) >> 24) 86 #define BTF_INT_OFFSET(VAL) (((VAL) & 0x00ff0000) >> 16) 87 #define BTF_INT_BITS(VAL) ((VAL) & 0x000000ff) 88 89 /* Attributes stored in the BTF_INT_ENCODING */ 90 #define BTF_INT_SIGNED (1 << 0) 91 #define BTF_INT_CHAR (1 << 1) 92 #define BTF_INT_BOOL (1 << 2) 93 94 /* BTF_KIND_ENUM is followed by multiple "struct btf_enum". 95 * The exact number of btf_enum is stored in the vlen (of the 96 * info in "struct btf_type"). 97 */ 98 struct btf_enum { 99 __u32 name_off; 100 __s32 val; 101 }; 102 103 /* BTF_KIND_ARRAY is followed by one "struct btf_array" */ 104 struct btf_array { 105 __u32 type; 106 __u32 index_type; 107 __u32 nelems; 108 }; 109 110 /* BTF_KIND_STRUCT and BTF_KIND_UNION are followed 111 * by multiple "struct btf_member". The exact number 112 * of btf_member is stored in the vlen (of the info in 113 * "struct btf_type"). 114 */ 115 struct btf_member { 116 __u32 name_off; 117 __u32 type; 118 /* If the type info kind_flag is set, the btf_member offset 119 * contains both member bitfield size and bit offset. The 120 * bitfield size is set for bitfield members. If the type 121 * info kind_flag is not set, the offset contains only bit 122 * offset. 123 */ 124 __u32 offset; 125 }; 126 127 /* If the struct/union type info kind_flag is set, the 128 * following two macros are used to access bitfield_size 129 * and bit_offset from btf_member.offset. 130 */ 131 #define BTF_MEMBER_BITFIELD_SIZE(val) ((val) >> 24) 132 #define BTF_MEMBER_BIT_OFFSET(val) ((val) & 0xffffff) 133 134 /* BTF_KIND_FUNC_PROTO is followed by multiple "struct btf_param". 135 * The exact number of btf_param is stored in the vlen (of the 136 * info in "struct btf_type"). 137 */ 138 struct btf_param { 139 __u32 name_off; 140 __u32 type; 141 }; 142 143 enum { 144 BTF_VAR_STATIC = 0, 145 BTF_VAR_GLOBAL_ALLOCATED, 146 }; 147 148 /* BTF_KIND_VAR is followed by a single "struct btf_var" to describe 149 * additional information related to the variable such as its linkage. 150 */ 151 struct btf_var { 152 __u32 linkage; 153 }; 154 155 /* BTF_KIND_DATASEC is followed by multiple "struct btf_var_secinfo" 156 * to describe all BTF_KIND_VAR types it contains along with it's 157 * in-section offset as well as size. 158 */ 159 struct btf_var_secinfo { 160 __u32 type; 161 __u32 offset; 162 __u32 size; 163 }; 164 165 #endif /* _UAPI__LINUX_BTF_H__ */ 166