Linux kernel mirror (for testing)
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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
11/*
12 * BTF layout section consists of a struct btf_layout for each known
13 * kind at BTF encoding time.
14 */
15struct btf_layout {
16 __u8 info_sz; /* size of singular element after btf_type */
17 __u8 elem_sz; /* size of each of btf_vlen(t) elements */
18 __u16 flags; /* currently unused */
19};
20
21struct btf_header {
22 __u16 magic;
23 __u8 version;
24 __u8 flags;
25 __u32 hdr_len;
26
27 /* All offsets are in bytes relative to the end of this header */
28 __u32 type_off; /* offset of type section */
29 __u32 type_len; /* length of type section */
30 __u32 str_off; /* offset of string section */
31 __u32 str_len; /* length of string section */
32 __u32 layout_off; /* offset of layout section */
33 __u32 layout_len; /* length of layout section */
34};
35
36/* Max # of type identifier */
37#define BTF_MAX_TYPE 0x000fffff
38/* Max offset into the string section */
39#define BTF_MAX_NAME_OFFSET 0x00ffffff
40/* Max # of struct/union/enum members or func args */
41#define BTF_MAX_VLEN 0xffff
42
43struct 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 * bit 31: kind_flag, currently used by
51 * struct, union, enum, fwd, enum64,
52 * decl_tag and type_tag
53 */
54 __u32 info;
55 /* "size" is used by INT, ENUM, STRUCT, UNION, DATASEC and ENUM64.
56 * "size" tells the size of the type it is describing.
57 *
58 * "type" is used by PTR, TYPEDEF, VOLATILE, CONST, RESTRICT,
59 * FUNC, FUNC_PROTO, VAR, DECL_TAG and TYPE_TAG.
60 * "type" is a type_id referring to another type.
61 */
62 union {
63 __u32 size;
64 __u32 type;
65 };
66};
67
68#define BTF_INFO_KIND(info) (((info) >> 24) & 0x1f)
69#define BTF_INFO_VLEN(info) ((info) & 0xffff)
70#define BTF_INFO_KFLAG(info) ((info) >> 31)
71
72enum {
73 BTF_KIND_UNKN = 0, /* Unknown */
74 BTF_KIND_INT = 1, /* Integer */
75 BTF_KIND_PTR = 2, /* Pointer */
76 BTF_KIND_ARRAY = 3, /* Array */
77 BTF_KIND_STRUCT = 4, /* Struct */
78 BTF_KIND_UNION = 5, /* Union */
79 BTF_KIND_ENUM = 6, /* Enumeration up to 32-bit values */
80 BTF_KIND_FWD = 7, /* Forward */
81 BTF_KIND_TYPEDEF = 8, /* Typedef */
82 BTF_KIND_VOLATILE = 9, /* Volatile */
83 BTF_KIND_CONST = 10, /* Const */
84 BTF_KIND_RESTRICT = 11, /* Restrict */
85 BTF_KIND_FUNC = 12, /* Function */
86 BTF_KIND_FUNC_PROTO = 13, /* Function Proto */
87 BTF_KIND_VAR = 14, /* Variable */
88 BTF_KIND_DATASEC = 15, /* Section */
89 BTF_KIND_FLOAT = 16, /* Floating point */
90 BTF_KIND_DECL_TAG = 17, /* Decl Tag */
91 BTF_KIND_TYPE_TAG = 18, /* Type Tag */
92 BTF_KIND_ENUM64 = 19, /* Enumeration up to 64-bit values */
93
94 NR_BTF_KINDS,
95 BTF_KIND_MAX = NR_BTF_KINDS - 1,
96};
97
98/* For some specific BTF_KIND, "struct btf_type" is immediately
99 * followed by extra data.
100 */
101
102/* BTF_KIND_INT is followed by a u32 and the following
103 * is the 32 bits arrangement:
104 */
105#define BTF_INT_ENCODING(VAL) (((VAL) & 0x0f000000) >> 24)
106#define BTF_INT_OFFSET(VAL) (((VAL) & 0x00ff0000) >> 16)
107#define BTF_INT_BITS(VAL) ((VAL) & 0x000000ff)
108
109/* Attributes stored in the BTF_INT_ENCODING */
110#define BTF_INT_SIGNED (1 << 0)
111#define BTF_INT_CHAR (1 << 1)
112#define BTF_INT_BOOL (1 << 2)
113
114/* BTF_KIND_ENUM is followed by multiple "struct btf_enum".
115 * The exact number of btf_enum is stored in the vlen (of the
116 * info in "struct btf_type").
117 */
118struct btf_enum {
119 __u32 name_off;
120 __s32 val;
121};
122
123/* BTF_KIND_ARRAY is followed by one "struct btf_array" */
124struct btf_array {
125 __u32 type;
126 __u32 index_type;
127 __u32 nelems;
128};
129
130/* BTF_KIND_STRUCT and BTF_KIND_UNION are followed
131 * by multiple "struct btf_member". The exact number
132 * of btf_member is stored in the vlen (of the info in
133 * "struct btf_type").
134 */
135struct btf_member {
136 __u32 name_off;
137 __u32 type;
138 /* If the type info kind_flag is set, the btf_member offset
139 * contains both member bitfield size and bit offset. The
140 * bitfield size is set for bitfield members. If the type
141 * info kind_flag is not set, the offset contains only bit
142 * offset.
143 */
144 __u32 offset;
145};
146
147/* If the struct/union type info kind_flag is set, the
148 * following two macros are used to access bitfield_size
149 * and bit_offset from btf_member.offset.
150 */
151#define BTF_MEMBER_BITFIELD_SIZE(val) ((val) >> 24)
152#define BTF_MEMBER_BIT_OFFSET(val) ((val) & 0xffffff)
153
154/* BTF_KIND_FUNC_PROTO is followed by multiple "struct btf_param".
155 * The exact number of btf_param is stored in the vlen (of the
156 * info in "struct btf_type").
157 */
158struct btf_param {
159 __u32 name_off;
160 __u32 type;
161};
162
163enum {
164 BTF_VAR_STATIC = 0,
165 BTF_VAR_GLOBAL_ALLOCATED = 1,
166 BTF_VAR_GLOBAL_EXTERN = 2,
167};
168
169enum btf_func_linkage {
170 BTF_FUNC_STATIC = 0,
171 BTF_FUNC_GLOBAL = 1,
172 BTF_FUNC_EXTERN = 2,
173};
174
175/* BTF_KIND_VAR is followed by a single "struct btf_var" to describe
176 * additional information related to the variable such as its linkage.
177 */
178struct btf_var {
179 __u32 linkage;
180};
181
182/* BTF_KIND_DATASEC is followed by multiple "struct btf_var_secinfo"
183 * to describe all BTF_KIND_VAR types it contains along with it's
184 * in-section offset as well as size.
185 */
186struct btf_var_secinfo {
187 __u32 type;
188 __u32 offset;
189 __u32 size;
190};
191
192/* BTF_KIND_DECL_TAG is followed by a single "struct btf_decl_tag" to describe
193 * additional information related to the tag applied location.
194 * If component_idx == -1, the tag is applied to a struct, union,
195 * variable or function. Otherwise, it is applied to a struct/union
196 * member or a func argument, and component_idx indicates which member
197 * or argument (0 ... vlen-1).
198 */
199struct btf_decl_tag {
200 __s32 component_idx;
201};
202
203/* BTF_KIND_ENUM64 is followed by multiple "struct btf_enum64".
204 * The exact number of btf_enum64 is stored in the vlen (of the
205 * info in "struct btf_type").
206 */
207struct btf_enum64 {
208 __u32 name_off;
209 __u32 val_lo32;
210 __u32 val_hi32;
211};
212
213#endif /* _UAPI__LINUX_BTF_H__ */