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
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
|
/* ScummVM - Graphic Adventure Engine
*
* ScummVM is the legal property of its developers, whose names
* are too numerous to list here. Please refer to the COPYRIGHT
* file distributed with this source distribution.
*
* This program 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 2
* of the License, or (at your option) any later version.
* This program 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 this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*
* $URL$
* $Id$
*
*/
#ifndef BACKENDS_ELF_H
#define BACKENDS_ELF_H
/* ELF stuff */
typedef unsigned short Elf32_Half, Elf32_Section;
typedef unsigned int Elf32_Word, Elf32_Addr, Elf32_Off;
typedef signed int Elf32_Sword;
typedef Elf32_Half Elf32_Versym;
#define EI_NIDENT (16)
#define SELFMAG 6
/* ELF File format structures. Look up ELF structure for more details */
// ELF header (contains info about the file)
typedef struct
{
unsigned char e_ident[EI_NIDENT]; /* Magic number and other info */
Elf32_Half e_type; /* Object file type */
Elf32_Half e_machine; /* Architecture */
Elf32_Word e_version; /* Object file version */
Elf32_Addr e_entry; /* Entry point virtual address */
Elf32_Off e_phoff; /* Program header table file offset */
Elf32_Off e_shoff; /* Section header table file offset */
Elf32_Word e_flags; /* Processor-specific flags */
Elf32_Half e_ehsize; /* ELF header size in bytes */
Elf32_Half e_phentsize; /* Program header table entry size */
Elf32_Half e_phnum; /* Program header table entry count */
Elf32_Half e_shentsize; /* Section header table entry size */
Elf32_Half e_shnum; /* Section header table entry count */
Elf32_Half e_shstrndx; /* Section header string table index */
} Elf32_Ehdr;
// Should be in e_ident
#define ELFMAG "\177ELF\1\1" /* ELF Magic number */
// e_type values
#define ET_NONE 0 /* no file type */
#define ET_REL 1 /* relocatable */
#define ET_EXEC 2 /* executable */
#define ET_DYN 3 /* shared object */
#define ET_CORE 4 /* core file */
// e_machine values
#define EM_MIPS 8
// Program header (contains info about segment)
typedef struct
{
Elf32_Word p_type; /* Segment type */
Elf32_Off p_offset; /* Segment file offset */
Elf32_Addr p_vaddr; /* Segment virtual address */
Elf32_Addr p_paddr; /* Segment physical address */
Elf32_Word p_filesz; /* Segment size in file */
Elf32_Word p_memsz; /* Segment size in memory */
Elf32_Word p_flags; /* Segment flags */
Elf32_Word p_align; /* Segment alignment */
} Elf32_Phdr;
// p_type values
#define PT_NULL 0 /* ignored */
#define PT_LOAD 1 /* loadable segment */
#define PT_DYNAMIC 2 /* dynamic linking info */
#define PT_INTERP 3 /* info about interpreter */
#define PT_NOTE 4 /* note segment */
#define PT_SHLIB 5 /* reserved */
#define PT_PHDR 6 /* Program header table */
#define PT_MIPS_REGINFO 0x70000000 /* register usage info */
// p_flags value
#define PF_X 1 /* execute */
#define PF_W 2 /* write */
#define PF_R 4 /* read */
// Section header (contains info about section)
typedef struct
{
Elf32_Word sh_name; /* Section name (string tbl index) */
Elf32_Word sh_type; /* Section type */
Elf32_Word sh_flags; /* Section flags */
Elf32_Addr sh_addr; /* Section virtual addr at execution */
Elf32_Off sh_offset; /* Section file offset */
Elf32_Word sh_size; /* Section size in bytes */
Elf32_Word sh_link; /* Link to another section */
Elf32_Word sh_info; /* Additional section information */
Elf32_Word sh_addralign; /* Section alignment */
Elf32_Word sh_entsize; /* Entry size if section holds table */
} Elf32_Shdr;
// sh_type values
#define SHT_NULL 0 /* Inactive section */
#define SHT_PROGBITS 1 /* Proprietary */
#define SHT_SYMTAB 2 /* Symbol table */
#define SHT_STRTAB 3 /* String table */
#define SHT_RELA 4 /* Relocation entries with addend */
#define SHT_HASH 5 /* Symbol hash table */
#define SHT_DYNAMIC 6 /* Info for dynamic linking */
#define SHT_NOTE 7 /* Note section */
#define SHT_NOBITS 8 /* Occupies no space */
#define SHT_REL 9 /* Relocation entries without addend */
#define SHT_SHLIB 10 /* Reserved */
#define SHT_DYNSYM 11 /* Minimal set of dynamic linking symbols */
#define SHT_MIPS_LIBLSIT 0x70000000 /* Info about dynamic shared object libs */
#define SHT_MIPS_CONFLICT 0x70000002 /* Conflicts btw executables and shared objects */
#define SHT_MIPS_GPTAB 0x70000003 /* Global pointer table */
// sh_flags values
#define SHF_WRITE 0 /* writable section */
#define SHF_ALLOC 2 /* section occupies memory */
#define SHF_EXECINSTR 4 /* machine instructions */
#define SHF_MIPS_GPREL 0x10000000 /* Must be made part of global data area */
// Symbol entry (contain info about a symbol)
typedef struct
{
Elf32_Word st_name; /* Symbol name (string tbl index) */
Elf32_Addr st_value; /* Symbol value */
Elf32_Word st_size; /* Symbol size */
unsigned char st_info; /* Symbol type and binding */
unsigned char st_other; /* Symbol visibility */
Elf32_Section st_shndx; /* Section index */
} Elf32_Sym;
// Extract from the st_info
#define SYM_TYPE(x) ((x)&0xF)
#define SYM_BIND(x) ((x)>>4)
// Symbol binding values from st_info
#define STB_LOCAL 0 /* Symbol not visible outside object */
#define STB_GLOBAL 1 /* Symbol visible to all object files */
#define STB_WEAK 2 /* Similar to STB_GLOBAL */
// Symbol type values from st_info
#define STT_NOTYPE 0 /* Not specified */
#define STT_OBJECT 1 /* Data object e.g. variable */
#define STT_FUNC 2 /* Function */
#define STT_SECTION 3 /* Section */
#define STT_FILE 4 /* Source file associated with object file */
// Special section header index values from st_shndex
#define SHN_UNDEF 0
#define SHN_LOPROC 0xFF00 /* Extended values */
#define SHN_ABS 0xFFF1 /* Absolute value: don't relocate */
#define SHN_COMMON 0xFFF2 /* Common block. Not allocated yet */
#define SHN_HIPROC 0xFF1F
#define SHN_HIRESERVE 0xFFFF
// Relocation entry (info about how to relocate)
typedef struct
{
Elf32_Addr r_offset; /* Address */
Elf32_Word r_info; /* Relocation type and symbol index */
} Elf32_Rel;
// Access macros for the relocation info
#define REL_TYPE(x) ((x)&0xFF) /* Extract relocation type */
#define REL_INDEX(x) ((x)>>8) /* Extract relocation index into symbol table */
// MIPS relocation types
#define R_MIPS_NONE 0
#define R_MIPS_16 1
#define R_MIPS_32 2
#define R_MIPS_REL32 3
#define R_MIPS_26 4
#define R_MIPS_HI16 5
#define R_MIPS_LO16 6
#define R_MIPS_GPREL16 7
#define R_MIPS_LITERAL 8
#define R_MIPS_GOT16 9
#define R_MIPS_PC16 10
#define R_MIPS_CALL16 11
#define R_MIPS_GPREL32 12
#define R_MIPS_GOTHI16 13
#define R_MIPS_GOTLO16 14
#define R_MIPS_CALLHI16 15
#define R_MIPS_CALLLO16 16
// Mock function to get value of global pointer
#define getGP() ({ \
unsigned int __valgp; \
__asm__ ("add %0, $gp, $0" : "=r"(__valgp) : ); \
__valgp; \
})
#endif /* BACKENDS_ELF_H */
|
