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