1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
|
/* Declarations and definitions relating to the BPF Type Format (BTF).
Copyright (C) 2021 Free Software Foundation, Inc.
This file is part of GCC.
GCC is free software; you can redistribute it and/or modify it
under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 3, or (at your option)
any later version.
GCC is distributed in the hope that it will be useful, but WITHOUT
ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public
License for more details.
You should have received a copy of the GNU General Public License
along with GCC; see the file COPYING3. If not see
<http://www.gnu.org/licenses/>. */
/* This file is derived from the BTF specification described in the
Linux kernel source tree (linux/Documentation/bpf/btf.rst). */
#ifndef _BTF_H_
#define _BTF_H_
#include <stdint.h>
#ifdef __cplusplus
extern "C"
{
#endif
/* BTF magic number to identify header, endianness. */
#define BTF_MAGIC 0xeb9f
/* Data format version number. */
#define BTF_VERSION 1
struct btf_header
{
uint16_t magic; /* Magic number (BTF_MAGIC). */
uint8_t version; /* Data format version (BTF_VERSION). */
uint8_t flags; /* Flags. Currently unused. */
uint32_t hdr_len; /* Length of this header (sizeof (struct btf_header)). */
/* Following offsets are relative to the end of this header. */
uint32_t type_off; /* Offset of type section, in bytes. */
uint32_t type_len; /* Length of type section, in bytes. */
uint32_t str_off; /* Offset of string section, in bytes. */
uint32_t str_len; /* Length of string section, in bytes. */
};
/* Maximum type identifier. */
#define BTF_MAX_TYPE 0x000fffff
/* Maximum offset into the string section. */
#define BTF_MAX_NAME_OFFSET 0x00ffffff
/* Maximum number of struct, union, enum members or func args. */
#define BTF_MAX_VLEN 0xffff
struct btf_type
{
uint32_t name_off; /* Offset in string section of type name. */
uint32_t info; /* Encoded kind, variant length, kind flag:
- bits 0-15: vlen
- bits 16-23: unused
- bits 24-27: kind
- bits 28-30: unused
- bit 31: kind_flag
See accessor macros below. */
/* SIZE is used by INT, ENUM, STRUCT, UNION, DATASEC kinds.
TYPE is used by PTR, TYPEDEF, VOLATILE, CONST, RESTRICT, FUNC,
FUNC_PROTO and VAR kinds. */
union
{
uint32_t size; /* Size of the entire type, in bytes. */
uint32_t type; /* A type_id referring to another type. */
};
};
/* The folloing macros access the information encoded in btf_type.info. */
/* Type kind. See below. */
#define BTF_INFO_KIND(info) (((info) >> 24) & 0x0f)
/* Number of entries of variable length data following certain type kinds.
For example, number of structure members, number of function parameters. */
#define BTF_INFO_VLEN(info) ((info) & 0xffff)
/* For BTF_KIND_FWD, 1 if forward to union, 0 if forward to struct.
For BTF_KIND_STRUCT and BTF_KIND_UNION, 1 if the struct/union contains
a bitfield. */
#define BTF_INFO_KFLAG(info) ((info) >> 31)
/* Encoding for struct btf_type.info. */
#define BTF_TYPE_INFO(kind, kflag, vlen) \
((((kflag) ? 1 : 0 ) << 31) | ((kind) << 24) | ((vlen) & 0xffff))
#define BTF_KIND_UNKN 0 /* Unknown or invalid. */
#define BTF_KIND_INT 1 /* Integer. */
#define BTF_KIND_PTR 2 /* Pointer. */
#define BTF_KIND_ARRAY 3 /* Array. */
#define BTF_KIND_STRUCT 4 /* Struct. */
#define BTF_KIND_UNION 5 /* Union. */
#define BTF_KIND_ENUM 6 /* Enumeration. */
#define BTF_KIND_FWD 7 /* Forward. */
#define BTF_KIND_TYPEDEF 8 /* Typedef. */
#define BTF_KIND_VOLATILE 9 /* Referenced type is volatile. */
#define BTF_KIND_CONST 10 /* Referenced type is const. */
#define BTF_KIND_RESTRICT 11 /* Restrict. */
#define BTF_KIND_FUNC 12 /* Subprogram. */
#define BTF_KIND_FUNC_PROTO 13 /* Function Prototype. */
#define BTF_KIND_VAR 14 /* Variable. */
#define BTF_KIND_DATASEC 15 /* Section such as .bss or .data. */
#define BTF_KIND_MAX BTF_KIND_DATASEC
#define NR_BTF_KINDS (BTF_KIND_MAX + 1)
/* For some BTF_KINDs, struct btf_type is immediately followed by
additional data describing the type. */
/* BTF_KIND_INT is followed by a 32-bit word, with the following
bit arrangement. */
#define BTF_INT_ENCODING(VAL) (((VAL) & 0x0f000000) >> 24)
#define BTF_INT_OFFSET(VAL) (((VAL) & 0x00ff0000) >> 16)
#define BTF_INT_BITS(VAL) ((VAL) & 0x000000ff)
#define BTF_INT_DATA(encoding, offset, bits) \
((((encoding) & 0x0f) << 24) | (((offset) & 0xff) << 16) | ((bits) & 0xff))
/* BTF_INT_ENCODING holds the following attribute flags. */
#define BTF_INT_SIGNED (1 << 0)
#define BTF_INT_CHAR (1 << 1)
#define BTF_INT_BOOL (1 << 2)
/* BTF_KIND_ENUM is followed by VLEN struct btf_enum entries,
which describe the enumerators. Note that BTF currently only
supports signed 32-bit enumerator values. */
struct btf_enum
{
uint32_t name_off; /* Offset in string section of enumerator name. */
int32_t val; /* Enumerator value. */
};
/* BTF_KIND_ARRAY is followed by a single struct btf_array. */
struct btf_array
{
uint32_t type; /* Type of array elements. */
uint32_t index_type; /* Type of array index. */
uint32_t nelems; /* Number of elements. 0 for unsized/variable length. */
};
/* BTF_KIND_STRUCT and BTF_KIND_UNION are followed by VLEN
struct btf_member. */
struct btf_member
{
uint32_t name_off; /* Offset in string section of member name. */
uint32_t type; /* Type of member. */
uint32_t offset; /* If the type info kind_flag is set, this contains
both the member bitfield size and bit offset,
according to the macros below. If kind_flag is not
set, offset contains only the bit offset (from the
beginning of the struct). */
};
/* If struct or union type info kind_flag is set, used to access member
bitfield size from btf_member.offset. */
#define BTF_MEMBER_BITFIELD_SIZE (val) ((val) >> 24)
/* If struct or union type info kind_flag is set, used to access member
bit offset from btf_member.offset. */
#define BTF_MEMBER_BIT_OFFSET (val) ((val) & 0x00ffffff)
/* BTF_KIND_FUNC_PROTO is followed by VLEN struct btf_param entries, which
describe the types of the function parameters. */
struct btf_param
{
uint32_t name_off; /* Offset in string section of parameter name. */
uint32_t type; /* Type of parameter. */
};
/* BTF_KIND_VAR is followed by a single struct btf_var, which describes
information about the variable. */
struct btf_var
{
uint32_t linkage; /* Currently only 0=static or 1=global. */
};
/* BTF_KIND_DATASEC is followed by VLEN struct btf_var_secinfo entries,
which describe all BTF_KIND_VAR types contained in the section. */
struct btf_var_secinfo
{
uint32_t type; /* Type of variable. */
uint32_t offset; /* In-section offset of variable (in bytes). */
uint32_t size; /* Size (in bytes) of variable. */
};
#ifdef __cplusplus
}
#endif
#endif /* _BTF_H_ */
|
