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