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__
6 #include <linux/types.h>
8 #define BTF_MAGIC 0xeB9F
9 #define BTF_MAGIC_SWAP 0x9FeB
11 #define BTF_FLAGS_COMPR 0x01
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 */
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
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)
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)
47 /* "info" bits arrangement
48 * bits 0-15: vlen (e.g. # of struct's members)
50 * bits 24-28: kind (e.g. int, ptr, array...etc)
55 /* "size" is used by INT, ENUM, STRUCT and UNION.
56 * "size" tells the size of the type it is describing.
58 * "type" is used by PTR, TYPEDEF, VOLATILE, CONST and RESTRICT.
59 * "type" is a type_id referring to another type.
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)
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
86 /* For some specific BTF_KIND, "struct btf_type" is immediately
87 * followed by extra data.
90 /* BTF_KIND_INT is followed by a u32 and the following
91 * is the 32 bits arrangement:
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)
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
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").
112 /* BTF_KIND_ARRAY is followed by one "struct btf_array" */
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").
127 __u32 offset; /* offset in bits */
130 #endif /* _UAPI__LINUX_BTF_H__ */