LLVM  14.0.0git
BTF.h
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1 //===-- BTF.h --------------------------------------------------*- C++ -*-===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 ///
9 /// \file
10 /// This file contains the layout of .BTF and .BTF.ext ELF sections.
11 ///
12 /// The binary layout for .BTF section:
13 /// struct Header
14 /// Type and Str subsections
15 /// The Type subsection is a collection of types with type id starting with 1.
16 /// The Str subsection is simply a collection of strings.
17 ///
18 /// The binary layout for .BTF.ext section:
19 /// struct ExtHeader
20 /// FuncInfo, LineInfo, FieldReloc and ExternReloc subsections
21 /// The FuncInfo subsection is defined as below:
22 /// BTFFuncInfo Size
23 /// struct SecFuncInfo for ELF section #1
24 /// A number of struct BPFFuncInfo for ELF section #1
25 /// struct SecFuncInfo for ELF section #2
26 /// A number of struct BPFFuncInfo for ELF section #2
27 /// ...
28 /// The LineInfo subsection is defined as below:
29 /// BPFLineInfo Size
30 /// struct SecLineInfo for ELF section #1
31 /// A number of struct BPFLineInfo for ELF section #1
32 /// struct SecLineInfo for ELF section #2
33 /// A number of struct BPFLineInfo for ELF section #2
34 /// ...
35 /// The FieldReloc subsection is defined as below:
36 /// BPFFieldReloc Size
37 /// struct SecFieldReloc for ELF section #1
38 /// A number of struct BPFFieldReloc for ELF section #1
39 /// struct SecFieldReloc for ELF section #2
40 /// A number of struct BPFFieldReloc for ELF section #2
41 /// ...
42 ///
43 /// The section formats are also defined at
44 /// https://github.com/torvalds/linux/blob/master/include/uapi/linux/btf.h
45 ///
46 //===----------------------------------------------------------------------===//
47 
48 #ifndef LLVM_LIB_TARGET_BPF_BTF_H
49 #define LLVM_LIB_TARGET_BPF_BTF_H
50 
51 namespace llvm {
52 namespace BTF {
53 
54 enum : uint32_t { MAGIC = 0xeB9F, VERSION = 1 };
55 
56 /// Sizes in bytes of various things in the BTF format.
57 enum {
58  HeaderSize = 24,
72 };
73 
74 /// The .BTF section header definition.
75 struct Header {
76  uint16_t Magic; ///< Magic value
77  uint8_t Version; ///< Version number
78  uint8_t Flags; ///< Extra flags
79  uint32_t HdrLen; ///< Length of this header
80 
81  /// All offsets are in bytes relative to the end of this header.
82  uint32_t TypeOff; ///< Offset of type section
83  uint32_t TypeLen; ///< Length of type section
84  uint32_t StrOff; ///< Offset of string section
85  uint32_t StrLen; ///< Length of string section
86 };
87 
88 enum : uint32_t {
89  MAX_VLEN = 0xffff ///< Max # of struct/union/enum members or func args
90 };
91 
92 enum TypeKinds : uint8_t {
93 #define HANDLE_BTF_KIND(ID, NAME) BTF_KIND_##NAME = ID,
94 #include "BTF.def"
95 };
96 
97 /// The BTF common type definition. Different kinds may have
98 /// additional information after this structure data.
99 struct CommonType {
100  /// Type name offset in the string table.
102 
103  /// "Info" bits arrangement:
104  /// Bits 0-15: vlen (e.g. # of struct's members)
105  /// Bits 16-23: unused
106  /// Bits 24-27: kind (e.g. int, ptr, array...etc)
107  /// Bits 28-30: unused
108  /// Bit 31: kind_flag, currently used by
109  /// struct, union, fwd and tag
111 
112  /// "Size" is used by INT, ENUM, STRUCT and UNION.
113  /// "Size" tells the size of the type it is describing.
114  ///
115  /// "Type" is used by PTR, TYPEDEF, VOLATILE, CONST, RESTRICT,
116  /// FUNC, FUNC_PROTO, VAR and TAG.
117  /// "Type" is a type_id referring to another type.
118  union {
121  };
122 };
123 
124 // For some specific BTF_KIND, "struct CommonType" is immediately
125 // followed by extra data.
126 
127 // BTF_KIND_INT is followed by a u32 and the following
128 // is the 32 bits arrangement:
129 // BTF_INT_ENCODING(VAL) : (((VAL) & 0x0f000000) >> 24)
130 // BTF_INT_OFFSET(VAL) : (((VAL & 0x00ff0000)) >> 16)
131 // BTF_INT_BITS(VAL) : ((VAL) & 0x000000ff)
132 
133 /// Attributes stored in the INT_ENCODING.
134 enum : uint8_t {
135  INT_SIGNED = (1 << 0),
136  INT_CHAR = (1 << 1),
137  INT_BOOL = (1 << 2)
138 };
139 
140 /// BTF_KIND_ENUM is followed by multiple "struct BTFEnum".
141 /// The exact number of btf_enum is stored in the vlen (of the
142 /// info in "struct CommonType").
143 struct BTFEnum {
144  uint32_t NameOff; ///< Enum name offset in the string table
145  int32_t Val; ///< Enum member value
146 };
147 
148 /// BTF_KIND_ARRAY is followed by one "struct BTFArray".
149 struct BTFArray {
150  uint32_t ElemType; ///< Element type
151  uint32_t IndexType; ///< Index type
152  uint32_t Nelems; ///< Number of elements for this array
153 };
154 
155 /// BTF_KIND_STRUCT and BTF_KIND_UNION are followed
156 /// by multiple "struct BTFMember". The exact number
157 /// of BTFMember is stored in the vlen (of the info in
158 /// "struct CommonType").
159 ///
160 /// If the struct/union contains any bitfield member,
161 /// the Offset below represents BitOffset (bits 0 - 23)
162 /// and BitFieldSize(bits 24 - 31) with BitFieldSize = 0
163 /// for non bitfield members. Otherwise, the Offset
164 /// represents the BitOffset.
165 struct BTFMember {
166  uint32_t NameOff; ///< Member name offset in the string table
167  uint32_t Type; ///< Member type
168  uint32_t Offset; ///< BitOffset or BitFieldSize+BitOffset
169 };
170 
171 /// BTF_KIND_FUNC_PROTO are followed by multiple "struct BTFParam".
172 /// The exist number of BTFParam is stored in the vlen (of the info
173 /// in "struct CommonType").
174 struct BTFParam {
177 };
178 
179 /// BTF_KIND_FUNC can be global, static or extern.
180 enum : uint8_t {
184 };
185 
186 /// Variable scoping information.
187 enum : uint8_t {
188  VAR_STATIC = 0, ///< Linkage: InternalLinkage
189  VAR_GLOBAL_ALLOCATED = 1, ///< Linkage: ExternalLinkage
190  VAR_GLOBAL_EXTERNAL = 2, ///< Linkage: ExternalLinkage
191 };
192 
193 /// BTF_KIND_DATASEC are followed by multiple "struct BTFDataSecVar".
194 /// The exist number of BTFDataSec is stored in the vlen (of the info
195 /// in "struct CommonType").
196 struct BTFDataSec {
197  uint32_t Type; ///< A BTF_KIND_VAR type
198  uint32_t Offset; ///< In-section offset
199  uint32_t Size; ///< Occupied memory size
200 };
201 
202 /// The .BTF.ext section header definition.
203 struct ExtHeader {
205  uint8_t Version;
206  uint8_t Flags;
208 
209  uint32_t FuncInfoOff; ///< Offset of func info section
210  uint32_t FuncInfoLen; ///< Length of func info section
211  uint32_t LineInfoOff; ///< Offset of line info section
212  uint32_t LineInfoLen; ///< Length of line info section
213  uint32_t FieldRelocOff; ///< Offset of offset reloc section
214  uint32_t FieldRelocLen; ///< Length of offset reloc section
215 };
216 
217 /// Specifying one function info.
218 struct BPFFuncInfo {
219  uint32_t InsnOffset; ///< Byte offset in the section
220  uint32_t TypeId; ///< Type id referring to .BTF type section
221 };
222 
223 /// Specifying function info's in one section.
224 struct SecFuncInfo {
225  uint32_t SecNameOff; ///< Section name index in the .BTF string table
226  uint32_t NumFuncInfo; ///< Number of func info's in this section
227 };
228 
229 /// Specifying one line info.
230 struct BPFLineInfo {
231  uint32_t InsnOffset; ///< Byte offset in this section
232  uint32_t FileNameOff; ///< File name index in the .BTF string table
233  uint32_t LineOff; ///< Line index in the .BTF string table
234  uint32_t LineCol; ///< Line num: line_col >> 10,
235  /// col num: line_col & 0x3ff
236 };
237 
238 /// Specifying line info's in one section.
239 struct SecLineInfo {
240  uint32_t SecNameOff; ///< Section name index in the .BTF string table
241  uint32_t NumLineInfo; ///< Number of line info's in this section
242 };
243 
244 /// Specifying one offset relocation.
246  uint32_t InsnOffset; ///< Byte offset in this section
247  uint32_t TypeID; ///< TypeID for the relocation
248  uint32_t OffsetNameOff; ///< The string to traverse types
249  uint32_t RelocKind; ///< What to patch the instruction
250 };
251 
252 /// Specifying offset relocation's in one section.
254  uint32_t SecNameOff; ///< Section name index in the .BTF string table
255  uint32_t NumFieldReloc; ///< Number of offset reloc's in this section
256 };
257 
258 } // End namespace BTF.
259 } // End namespace llvm.
260 
261 #endif
llvm::BTF::BPFLineInfoSize
@ BPFLineInfoSize
Definition: BTF.h:70
llvm::BTF::BTFMember
BTF_KIND_STRUCT and BTF_KIND_UNION are followed by multiple "struct BTFMember".
Definition: BTF.h:165
llvm::BTF::FUNC_EXTERN
@ FUNC_EXTERN
Definition: BTF.h:183
llvm
---------------------— PointerInfo ------------------------------------—
Definition: AllocatorList.h:23
llvm::BTF::BTFDataSec::Type
uint32_t Type
A BTF_KIND_VAR type.
Definition: BTF.h:197
llvm::BTF::SecFuncInfoSize
@ SecFuncInfoSize
Definition: BTF.h:66
llvm::BTF::BTFEnum
BTF_KIND_ENUM is followed by multiple "struct BTFEnum".
Definition: BTF.h:143
llvm::BTF::MAGIC
@ MAGIC
Definition: BTF.h:54
llvm::BTF::BPFFieldReloc::TypeID
uint32_t TypeID
TypeID for the relocation.
Definition: BTF.h:247
llvm::BTF::Header::TypeLen
uint32_t TypeLen
Length of type section.
Definition: BTF.h:83
llvm::BTF::SecLineInfoSize
@ SecLineInfoSize
Definition: BTF.h:67
llvm::BTF::SecLineInfo
Specifying line info's in one section.
Definition: BTF.h:239
llvm::BTF::INT_SIGNED
@ INT_SIGNED
Definition: BTF.h:135
llvm::BTF::ExtHeader::Flags
uint8_t Flags
Definition: BTF.h:206
llvm::BTF::SecFieldReloc
Specifying offset relocation's in one section.
Definition: BTF.h:253
llvm::BTF::FUNC_GLOBAL
@ FUNC_GLOBAL
Definition: BTF.h:182
llvm::BTF::BTFMember::Type
uint32_t Type
Member type.
Definition: BTF.h:167
llvm::BTF::SecLineInfo::NumLineInfo
uint32_t NumLineInfo
Number of line info's in this section.
Definition: BTF.h:241
llvm::BTF::BTFDataSec::Size
uint32_t Size
Occupied memory size.
Definition: BTF.h:199
llvm::BTF::ExtHeader::FuncInfoOff
uint32_t FuncInfoOff
Offset of func info section.
Definition: BTF.h:209
llvm::BTF::MAX_VLEN
@ MAX_VLEN
Max # of struct/union/enum members or func args.
Definition: BTF.h:89
llvm::BTF::BTFParam::NameOff
uint32_t NameOff
Definition: BTF.h:175
llvm::BTF::BTFArray::Nelems
uint32_t Nelems
Number of elements for this array.
Definition: BTF.h:152
llvm::BTF::SecFuncInfo::SecNameOff
uint32_t SecNameOff
Section name index in the .BTF string table.
Definition: BTF.h:225
llvm::BTF::SecLineInfo::SecNameOff
uint32_t SecNameOff
Section name index in the .BTF string table.
Definition: BTF.h:240
llvm::BTF::ExtHeader::FieldRelocLen
uint32_t FieldRelocLen
Length of offset reloc section.
Definition: BTF.h:214
llvm::BTF::BTFDataSecVarSize
@ BTFDataSecVarSize
Definition: BTF.h:65
llvm::BTF::VAR_STATIC
@ VAR_STATIC
Linkage: InternalLinkage.
Definition: BTF.h:188
llvm::BTF::SecFuncInfo
Specifying function info's in one section.
Definition: BTF.h:224
llvm::BTF::Header::HdrLen
uint32_t HdrLen
Length of this header.
Definition: BTF.h:79
llvm::BTF::BPFLineInfo
Specifying one line info.
Definition: BTF.h:230
llvm::BTF::SecFieldRelocSize
@ SecFieldRelocSize
Definition: BTF.h:68
llvm::BTF::TypeKinds
TypeKinds
Definition: BTF.h:92
llvm::BTF::BPFFieldReloc::OffsetNameOff
uint32_t OffsetNameOff
The string to traverse types.
Definition: BTF.h:248
llvm::BTF::BTFMember::Offset
uint32_t Offset
BitOffset or BitFieldSize+BitOffset.
Definition: BTF.h:168
llvm::BTF::BPFFuncInfo::TypeId
uint32_t TypeId
Type id referring to .BTF type section.
Definition: BTF.h:220
llvm::BTF::ExtHeader::Magic
uint16_t Magic
Definition: BTF.h:204
llvm::BTF::Header::Flags
uint8_t Flags
Extra flags.
Definition: BTF.h:78
llvm::BTF::ExtHeader::FuncInfoLen
uint32_t FuncInfoLen
Length of func info section.
Definition: BTF.h:210
llvm::BTF::BPFLineInfo::FileNameOff
uint32_t FileNameOff
File name index in the .BTF string table.
Definition: BTF.h:232
llvm::BTF::BTFMember::NameOff
uint32_t NameOff
Member name offset in the string table.
Definition: BTF.h:166
llvm::BTF::ExtHeader::HdrLen
uint32_t HdrLen
Definition: BTF.h:207
llvm::BTF::VERSION
@ VERSION
Definition: BTF.h:54
llvm::BTF::HeaderSize
@ HeaderSize
Definition: BTF.h:58
llvm::BTF::Header::Magic
uint16_t Magic
Magic value.
Definition: BTF.h:76
llvm::BTF::SecFieldReloc::NumFieldReloc
uint32_t NumFieldReloc
Number of offset reloc's in this section.
Definition: BTF.h:255
llvm::BTF::BTFEnumSize
@ BTFEnumSize
Definition: BTF.h:62
llvm::BTF::ExtHeader::Version
uint8_t Version
Definition: BTF.h:205
llvm::BTF::BTFMemberSize
@ BTFMemberSize
Definition: BTF.h:63
llvm::BTF::ExtHeader::LineInfoOff
uint32_t LineInfoOff
Offset of line info section.
Definition: BTF.h:211
llvm::BTF::INT_BOOL
@ INT_BOOL
Definition: BTF.h:137
llvm::BTF::BTFParam
BTF_KIND_FUNC_PROTO are followed by multiple "struct BTFParam".
Definition: BTF.h:174
llvm::BTF::BTFArray::IndexType
uint32_t IndexType
Index type.
Definition: BTF.h:151
llvm::BTF::BPFLineInfo::LineOff
uint32_t LineOff
Line index in the .BTF string table.
Definition: BTF.h:233
llvm::BTF::BTFParam::Type
uint32_t Type
Definition: BTF.h:176
llvm::BTF::BTFArraySize
@ BTFArraySize
Definition: BTF.h:61
llvm::BTF::BPFFieldReloc::InsnOffset
uint32_t InsnOffset
Byte offset in this section.
Definition: BTF.h:246
llvm::BTF::CommonType
The BTF common type definition.
Definition: BTF.h:99
llvm::BTF::ExtHeader::FieldRelocOff
uint32_t FieldRelocOff
Offset of offset reloc section.
Definition: BTF.h:213
llvm::BTF::ExtHeader
The .BTF.ext section header definition.
Definition: BTF.h:203
llvm::BTF::BPFFuncInfo::InsnOffset
uint32_t InsnOffset
Byte offset in the section.
Definition: BTF.h:219
llvm::BTF::Header::StrOff
uint32_t StrOff
Offset of string section.
Definition: BTF.h:84
uint32_t
llvm::BTF::BPFFieldReloc
Specifying one offset relocation.
Definition: BTF.h:245
llvm::BTF::BTFDataSec
BTF_KIND_DATASEC are followed by multiple "struct BTFDataSecVar".
Definition: BTF.h:196
llvm::BTF::BTFEnum::Val
int32_t Val
Enum member value.
Definition: BTF.h:145
llvm::BTF::BTFArray::ElemType
uint32_t ElemType
Element type.
Definition: BTF.h:150
llvm::BTF::BTFEnum::NameOff
uint32_t NameOff
Enum name offset in the string table.
Definition: BTF.h:144
llvm::BTF::BPFFieldReloc::RelocKind
uint32_t RelocKind
What to patch the instruction.
Definition: BTF.h:249
llvm::BTF::CommonType::Info
uint32_t Info
"Info" bits arrangement: Bits 0-15: vlen (e.g.
Definition: BTF.h:110
llvm::BTF::BTFDataSec::Offset
uint32_t Offset
In-section offset.
Definition: BTF.h:198
uint16_t
llvm::BTF::Header::TypeOff
uint32_t TypeOff
All offsets are in bytes relative to the end of this header.
Definition: BTF.h:82
llvm::BTF::Header::Version
uint8_t Version
Version number.
Definition: BTF.h:77
llvm::BTF::BPFFuncInfo
Specifying one function info.
Definition: BTF.h:218
llvm::BTF::VAR_GLOBAL_ALLOCATED
@ VAR_GLOBAL_ALLOCATED
Linkage: ExternalLinkage.
Definition: BTF.h:189
llvm::BTF::Header::StrLen
uint32_t StrLen
Length of string section.
Definition: BTF.h:85
llvm::BTF::Header
The .BTF section header definition.
Definition: BTF.h:75
llvm::BTF::BTFParamSize
@ BTFParamSize
Definition: BTF.h:64
llvm::BTF::INT_CHAR
@ INT_CHAR
Definition: BTF.h:136
llvm::BTF::SecFuncInfo::NumFuncInfo
uint32_t NumFuncInfo
Number of func info's in this section.
Definition: BTF.h:226
llvm::BTF::CommonType::NameOff
uint32_t NameOff
Type name offset in the string table.
Definition: BTF.h:101
llvm::BTF::FUNC_STATIC
@ FUNC_STATIC
Definition: BTF.h:181
llvm::BTF::VAR_GLOBAL_EXTERNAL
@ VAR_GLOBAL_EXTERNAL
Linkage: ExternalLinkage.
Definition: BTF.h:190
llvm::BTF::SecFieldReloc::SecNameOff
uint32_t SecNameOff
Section name index in the .BTF string table.
Definition: BTF.h:254
llvm::BTF::CommonType::Type
uint32_t Type
Definition: BTF.h:120
llvm::BTF::ExtHeaderSize
@ ExtHeaderSize
Definition: BTF.h:59
llvm::BTF::BPFFuncInfoSize
@ BPFFuncInfoSize
Definition: BTF.h:69
llvm::BTF::BPFLineInfo::InsnOffset
uint32_t InsnOffset
Byte offset in this section.
Definition: BTF.h:231
llvm::BTF::ExtHeader::LineInfoLen
uint32_t LineInfoLen
Length of line info section.
Definition: BTF.h:212
llvm::BTF::CommonType::Size
uint32_t Size
Definition: BTF.h:119
llvm::BTF::CommonTypeSize
@ CommonTypeSize
Definition: BTF.h:60
llvm::BTF::BPFLineInfo::LineCol
uint32_t LineCol
Line num: line_col >> 10, col num: line_col & 0x3ff.
Definition: BTF.h:234
llvm::BTF::BPFFieldRelocSize
@ BPFFieldRelocSize
Definition: BTF.h:71
llvm::BTF::BTFArray
BTF_KIND_ARRAY is followed by one "struct BTFArray".
Definition: BTF.h:149