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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
11struct 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 0x000fffff
26/* Max offset into the string section */
27#define BTF_MAX_NAME_OFFSET 0x00ffffff
28/* Max # of struct/union/enum members or func args */
29#define BTF_MAX_VLEN 0xffff
30
31struct 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 28-30: unused
38 * bit 31: kind_flag, currently used by
39 * struct, union and fwd
40 */
41 __u32 info;
42 /* "size" is used by INT, ENUM, STRUCT, UNION and DATASEC.
43 * "size" tells the size of the type it is describing.
44 *
45 * "type" is used by PTR, TYPEDEF, VOLATILE, CONST, RESTRICT,
46 * FUNC, FUNC_PROTO and VAR.
47 * "type" is a type_id referring to another type.
48 */
49 union {
50 __u32 size;
51 __u32 type;
52 };
53};
54
55#define BTF_INFO_KIND(info) (((info) >> 24) & 0x1f)
56#define BTF_INFO_VLEN(info) ((info) & 0xffff)
57#define BTF_INFO_KFLAG(info) ((info) >> 31)
58
59#define BTF_KIND_UNKN 0 /* Unknown */
60#define BTF_KIND_INT 1 /* Integer */
61#define BTF_KIND_PTR 2 /* Pointer */
62#define BTF_KIND_ARRAY 3 /* Array */
63#define BTF_KIND_STRUCT 4 /* Struct */
64#define BTF_KIND_UNION 5 /* Union */
65#define BTF_KIND_ENUM 6 /* Enumeration */
66#define BTF_KIND_FWD 7 /* Forward */
67#define BTF_KIND_TYPEDEF 8 /* Typedef */
68#define BTF_KIND_VOLATILE 9 /* Volatile */
69#define BTF_KIND_CONST 10 /* Const */
70#define BTF_KIND_RESTRICT 11 /* Restrict */
71#define BTF_KIND_FUNC 12 /* Function */
72#define BTF_KIND_FUNC_PROTO 13 /* Function Proto */
73#define BTF_KIND_VAR 14 /* Variable */
74#define BTF_KIND_DATASEC 15 /* Section */
75#define BTF_KIND_FLOAT 16 /* Floating point */
76#define BTF_KIND_MAX BTF_KIND_FLOAT
77#define NR_BTF_KINDS (BTF_KIND_MAX + 1)
78
79/* For some specific BTF_KIND, "struct btf_type" is immediately
80 * followed by extra data.
81 */
82
83/* BTF_KIND_INT is followed by a u32 and the following
84 * is the 32 bits arrangement:
85 */
86#define BTF_INT_ENCODING(VAL) (((VAL) & 0x0f000000) >> 24)
87#define BTF_INT_OFFSET(VAL) (((VAL) & 0x00ff0000) >> 16)
88#define BTF_INT_BITS(VAL) ((VAL) & 0x000000ff)
89
90/* Attributes stored in the BTF_INT_ENCODING */
91#define BTF_INT_SIGNED (1 << 0)
92#define BTF_INT_CHAR (1 << 1)
93#define BTF_INT_BOOL (1 << 2)
94
95/* BTF_KIND_ENUM is followed by multiple "struct btf_enum".
96 * The exact number of btf_enum is stored in the vlen (of the
97 * info in "struct btf_type").
98 */
99struct btf_enum {
100 __u32 name_off;
101 __s32 val;
102};
103
104/* BTF_KIND_ARRAY is followed by one "struct btf_array" */
105struct btf_array {
106 __u32 type;
107 __u32 index_type;
108 __u32 nelems;
109};
110
111/* BTF_KIND_STRUCT and BTF_KIND_UNION are followed
112 * by multiple "struct btf_member". The exact number
113 * of btf_member is stored in the vlen (of the info in
114 * "struct btf_type").
115 */
116struct btf_member {
117 __u32 name_off;
118 __u32 type;
119 /* If the type info kind_flag is set, the btf_member offset
120 * contains both member bitfield size and bit offset. The
121 * bitfield size is set for bitfield members. If the type
122 * info kind_flag is not set, the offset contains only bit
123 * offset.
124 */
125 __u32 offset;
126};
127
128/* If the struct/union type info kind_flag is set, the
129 * following two macros are used to access bitfield_size
130 * and bit_offset from btf_member.offset.
131 */
132#define BTF_MEMBER_BITFIELD_SIZE(val) ((val) >> 24)
133#define BTF_MEMBER_BIT_OFFSET(val) ((val) & 0xffffff)
134
135/* BTF_KIND_FUNC_PROTO is followed by multiple "struct btf_param".
136 * The exact number of btf_param is stored in the vlen (of the
137 * info in "struct btf_type").
138 */
139struct btf_param {
140 __u32 name_off;
141 __u32 type;
142};
143
144enum {
145 BTF_VAR_STATIC = 0,
146 BTF_VAR_GLOBAL_ALLOCATED = 1,
147 BTF_VAR_GLOBAL_EXTERN = 2,
148};
149
150enum btf_func_linkage {
151 BTF_FUNC_STATIC = 0,
152 BTF_FUNC_GLOBAL = 1,
153 BTF_FUNC_EXTERN = 2,
154};
155
156/* BTF_KIND_VAR is followed by a single "struct btf_var" to describe
157 * additional information related to the variable such as its linkage.
158 */
159struct btf_var {
160 __u32 linkage;
161};
162
163/* BTF_KIND_DATASEC is followed by multiple "struct btf_var_secinfo"
164 * to describe all BTF_KIND_VAR types it contains along with it's
165 * in-section offset as well as size.
166 */
167struct btf_var_secinfo {
168 __u32 type;
169 __u32 offset;
170 __u32 size;
171};
172
173#endif /* _UAPI__LINUX_BTF_H__ */