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
|
/* 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.
*
*/
#include "common/scummsys.h"
#if defined(DYNAMIC_MODULES) && defined(USE_ELF_LOADER) && defined(ARM_TARGET)
#include "backends/plugins/elf/arm-loader.h"
#include "common/debug.h"
bool ARMDLObject::relocate(Elf32_Off offset, Elf32_Word size, byte *relSegment) {
Elf32_Rel *rel = 0; //relocation entry
// Allocate memory for relocation table
if (!(rel = (Elf32_Rel *)malloc(size))) {
warning("elfloader: Out of memory.");
return false;
}
// Read in our relocation table
if (!_file->seek(offset, SEEK_SET) || _file->read(rel, size) != size) {
warning("elfloader: Relocation table load failed.");
free(rel);
return false;
}
// Treat each relocation entry. Loop over all of them
uint32 cnt = size / sizeof(*rel);
debug(2, "elfloader: Loaded relocation table. %d entries. base address=%p", cnt, relSegment);
int32 a = 0;
uint32 relocation = 0;
// Loop over relocation entries
for (uint32 i = 0; i < cnt; i++) {
// Get the symbol this relocation entry is referring to
Elf32_Sym *sym = _symtab + (REL_INDEX(rel[i].r_info));
// Get the target instruction in the code. TODO: repect _segmentVMA
uint32 *target = (uint32 *)((byte *)relSegment + rel[i].r_offset);
uint32 origTarget = *target; //Save for debugging
// Act differently based on the type of relocation
switch (REL_TYPE(rel[i].r_info)) {
case R_ARM_ABS32:
if (sym->st_shndx < SHN_LOPROC) { // Only shift for plugin section.
a = *target; // Get full 32 bits of addend
relocation = a + Elf32_Addr(_segment); // Shift by main offset
*target = relocation;
debug(8, "elfloader: R_ARM_ABS32: i=%d, a=%x, origTarget=%x, target=%x", i, a, origTarget, *target);
}
break;
case R_ARM_THM_CALL:
debug(8, "elfloader: R_ARM_THM_CALL: PC-relative jump, ld takes care of necessary relocation work for us.");
break;
case R_ARM_CALL:
debug(8, "elfloader: R_ARM_CALL: PC-relative jump, ld takes care of necessary relocation work for us.");
break;
case R_ARM_JUMP24:
debug(8, "elfloader: R_ARM_JUMP24: PC-relative jump, ld takes care of all relocation work for us.");
break;
case R_ARM_V4BX:
debug(8, "elfloader: R_ARM_V4BX: No relocation calculation necessary.");
break;
default:
warning("elfloader: Unknown relocation type %d.", REL_TYPE(rel[i].r_info));
free(rel);
return false;
}
}
free(rel);
return true;
}
bool ARMDLObject::relocateRels(Elf32_Ehdr *ehdr, Elf32_Shdr *shdr) {
// Loop over sections, finding relocation sections
for (uint32 i = 0; i < ehdr->e_shnum; i++) {
Elf32_Shdr *curShdr = &(shdr[i]);
if ((curShdr->sh_type == SHT_REL || curShdr->sh_type == SHT_RELA) && // Check for a relocation section
curShdr->sh_entsize == sizeof(Elf32_Rel) && // Check for proper relocation size
int32(curShdr->sh_link) == _symtab_sect && // Check that the sh_link connects to our symbol table
curShdr->sh_info < ehdr->e_shnum && // Check that the relocated section exists
(shdr[curShdr->sh_info].sh_flags & SHF_ALLOC)) { // Check if relocated section resides in memory
if (curShdr->sh_type == SHT_RELA) {
warning("elfloader: RELA entries not supported yet!");
return false;
}
if (!relocate(curShdr->sh_offset, curShdr->sh_size, _segment))
return false;
}
}
return true;
}
#endif /* defined(DYNAMIC_MODULES) && defined(USE_ELF_LOADER) && defined(ARM_TARGET) */
|
