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_MAGIC_SWAP 0x9FeB 10 #define BTF_VERSION 1 11 #define BTF_FLAGS_COMPR 0x01 12 13 struct btf_header { 14 __u16 magic; 15 __u8 version; 16 __u8 flags; 17 18 __u32 parent_label; 19 __u32 parent_name; 20 21 /* All offsets are in bytes relative to the end of this header */ 22 __u32 label_off; /* offset of label section */ 23 __u32 object_off; /* offset of data object section*/ 24 __u32 func_off; /* offset of function section */ 25 __u32 type_off; /* offset of type section */ 26 __u32 str_off; /* offset of string section */ 27 __u32 str_len; /* length of string section */ 28 }; 29 30 /* Max # of type identifier */ 31 #define BTF_MAX_TYPE 0x7fffffff 32 /* Max offset into the string section */ 33 #define BTF_MAX_NAME_OFFSET 0x7fffffff 34 /* Max # of struct/union/enum members or func args */ 35 #define BTF_MAX_VLEN 0xffff 36 37 /* The type id is referring to a parent BTF */ 38 #define BTF_TYPE_PARENT(id) (((id) >> 31) & 0x1) 39 #define BTF_TYPE_ID(id) ((id) & BTF_MAX_TYPE) 40 41 /* String is in the ELF string section */ 42 #define BTF_STR_TBL_ELF_ID(ref) (((ref) >> 31) & 0x1) 43 #define BTF_STR_OFFSET(ref) ((ref) & BTF_MAX_NAME_OFFSET) 44 45 struct btf_type { 46 __u32 name; 47 /* "info" bits arrangement 48 * bits 0-15: vlen (e.g. # of struct's members) 49 * bits 16-23: unused 50 * bits 24-28: kind (e.g. int, ptr, array...etc) 51 * bits 29-30: unused 52 * bits 31: root 53 */ 54 __u32 info; 55 /* "size" is used by INT, ENUM, STRUCT and UNION. 56 * "size" tells the size of the type it is describing. 57 * 58 * "type" is used by PTR, TYPEDEF, VOLATILE, CONST and RESTRICT. 59 * "type" is a type_id referring to another type. 60 */ 61 union { 62 __u32 size; 63 __u32 type; 64 }; 65 }; 66 67 #define BTF_INFO_KIND(info) (((info) >> 24) & 0x1f) 68 #define BTF_INFO_ISROOT(info) (!!(((info) >> 24) & 0x80)) 69 #define BTF_INFO_VLEN(info) ((info) & 0xffff) 70 71 #define BTF_KIND_UNKN 0 /* Unknown */ 72 #define BTF_KIND_INT 1 /* Integer */ 73 #define BTF_KIND_PTR 2 /* Pointer */ 74 #define BTF_KIND_ARRAY 3 /* Array */ 75 #define BTF_KIND_STRUCT 4 /* Struct */ 76 #define BTF_KIND_UNION 5 /* Union */ 77 #define BTF_KIND_ENUM 6 /* Enumeration */ 78 #define BTF_KIND_FWD 7 /* Forward */ 79 #define BTF_KIND_TYPEDEF 8 /* Typedef */ 80 #define BTF_KIND_VOLATILE 9 /* Volatile */ 81 #define BTF_KIND_CONST 10 /* Const */ 82 #define BTF_KIND_RESTRICT 11 /* Restrict */ 83 #define BTF_KIND_MAX 11 84 #define NR_BTF_KINDS 12 85 86 /* For some specific BTF_KIND, "struct btf_type" is immediately 87 * followed by extra data. 88 */ 89 90 /* BTF_KIND_INT is followed by a u32 and the following 91 * is the 32 bits arrangement: 92 */ 93 #define BTF_INT_ENCODING(VAL) (((VAL) & 0xff000000) >> 24) 94 #define BTF_INT_OFFSET(VAL) (((VAL & 0x00ff0000)) >> 16) 95 #define BTF_INT_BITS(VAL) ((VAL) & 0x0000ffff) 96 97 /* Attributes stored in the BTF_INT_ENCODING */ 98 #define BTF_INT_SIGNED 0x1 99 #define BTF_INT_CHAR 0x2 100 #define BTF_INT_BOOL 0x4 101 #define BTF_INT_VARARGS 0x8 102 103 /* BTF_KIND_ENUM is followed by multiple "struct btf_enum". 104 * The exact number of btf_enum is stored in the vlen (of the 105 * info in "struct btf_type"). 106 */ 107 struct btf_enum { 108 __u32 name; 109 __s32 val; 110 }; 111 112 /* BTF_KIND_ARRAY is followed by one "struct btf_array" */ 113 struct btf_array { 114 __u32 type; 115 __u32 index_type; 116 __u32 nelems; 117 }; 118 119 /* BTF_KIND_STRUCT and BTF_KIND_UNION are followed 120 * by multiple "struct btf_member". The exact number 121 * of btf_member is stored in the vlen (of the info in 122 * "struct btf_type"). 123 */ 124 struct btf_member { 125 __u32 name; 126 __u32 type; 127 __u32 offset; /* offset in bits */ 128 }; 129 130 #endif /* _UAPI__LINUX_BTF_H__ */ 131