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 0x0000ffff 26 /* Max offset into the string section */ 27 #define BTF_MAX_NAME_OFFSET 0x0000ffff 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 28-31: unused 38 */ 39 __u32 info; 40 /* "size" is used by INT, ENUM, STRUCT and UNION. 41 * "size" tells the size of the type it is describing. 42 * 43 * "type" is used by PTR, TYPEDEF, VOLATILE, CONST and RESTRICT. 44 * "type" is a type_id referring to another type. 45 */ 46 union { 47 __u32 size; 48 __u32 type; 49 }; 50 }; 51 52 #define BTF_INFO_KIND(info) (((info) >> 24) & 0x0f) 53 #define BTF_INFO_VLEN(info) ((info) & 0xffff) 54 55 #define BTF_KIND_UNKN 0 /* Unknown */ 56 #define BTF_KIND_INT 1 /* Integer */ 57 #define BTF_KIND_PTR 2 /* Pointer */ 58 #define BTF_KIND_ARRAY 3 /* Array */ 59 #define BTF_KIND_STRUCT 4 /* Struct */ 60 #define BTF_KIND_UNION 5 /* Union */ 61 #define BTF_KIND_ENUM 6 /* Enumeration */ 62 #define BTF_KIND_FWD 7 /* Forward */ 63 #define BTF_KIND_TYPEDEF 8 /* Typedef */ 64 #define BTF_KIND_VOLATILE 9 /* Volatile */ 65 #define BTF_KIND_CONST 10 /* Const */ 66 #define BTF_KIND_RESTRICT 11 /* Restrict */ 67 #define BTF_KIND_MAX 11 68 #define NR_BTF_KINDS 12 69 70 /* For some specific BTF_KIND, "struct btf_type" is immediately 71 * followed by extra data. 72 */ 73 74 /* BTF_KIND_INT is followed by a u32 and the following 75 * is the 32 bits arrangement: 76 */ 77 #define BTF_INT_ENCODING(VAL) (((VAL) & 0x0f000000) >> 24) 78 #define BTF_INT_OFFSET(VAL) (((VAL & 0x00ff0000)) >> 16) 79 #define BTF_INT_BITS(VAL) ((VAL) & 0x000000ff) 80 81 /* Attributes stored in the BTF_INT_ENCODING */ 82 #define BTF_INT_SIGNED (1 << 0) 83 #define BTF_INT_CHAR (1 << 1) 84 #define BTF_INT_BOOL (1 << 2) 85 86 /* BTF_KIND_ENUM is followed by multiple "struct btf_enum". 87 * The exact number of btf_enum is stored in the vlen (of the 88 * info in "struct btf_type"). 89 */ 90 struct btf_enum { 91 __u32 name_off; 92 __s32 val; 93 }; 94 95 /* BTF_KIND_ARRAY is followed by one "struct btf_array" */ 96 struct btf_array { 97 __u32 type; 98 __u32 index_type; 99 __u32 nelems; 100 }; 101 102 /* BTF_KIND_STRUCT and BTF_KIND_UNION are followed 103 * by multiple "struct btf_member". The exact number 104 * of btf_member is stored in the vlen (of the info in 105 * "struct btf_type"). 106 */ 107 struct btf_member { 108 __u32 name_off; 109 __u32 type; 110 __u32 offset; /* offset in bits */ 111 }; 112 113 #endif /* _UAPI__LINUX_BTF_H__ */ 114
