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
|
/* dl.c - arch-dependent part of loadable module support */
/*
* GRUB -- GRand Unified Bootloader
* Copyright (C) 2002,2004,2005,2007,2009 Free Software Foundation, Inc.
*
* GRUB 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 of the License, or
* (at your option) any later version.
*
* GRUB 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 GRUB. If not, see <http://www.gnu.org/licenses/>.
*/
#include <grub/dl.h>
#include <grub/elf.h>
#include <grub/misc.h>
#include <grub/err.h>
#include <grub/i18n.h>
/* Check if EHDR is a valid ELF header. */
grub_err_t
grub_arch_dl_check_header (void *ehdr)
{
Elf_Ehdr *e = ehdr;
/* Check the magic numbers. */
if (e->e_ident[EI_CLASS] != ELFCLASS32
|| e->e_ident[EI_DATA] != ELFDATA2MSB
|| e->e_machine != EM_PPC)
return grub_error (GRUB_ERR_BAD_OS, N_("invalid arch-dependent ELF magic"));
return GRUB_ERR_NONE;
}
/* For low-endian reverse lis and addr_high as well as ori and addr_low. */
struct trampoline
{
grub_uint32_t lis;
grub_uint32_t ori;
grub_uint32_t mtctr;
grub_uint32_t bctr;
};
static const struct trampoline trampoline_template =
{
0x3d800000,
0x618c0000,
0x7d8903a6,
0x4e800420,
};
#pragma GCC diagnostic ignored "-Wcast-align"
grub_err_t
grub_arch_dl_get_tramp_got_size (const void *ehdr, grub_size_t *tramp,
grub_size_t *got)
{
const Elf_Ehdr *e = ehdr;
const Elf_Shdr *s;
unsigned i;
*tramp = 0;
*got = 0;
for (i = 0, s = (const Elf_Shdr *) ((const char *) e + e->e_shoff);
i < e->e_shnum;
i++, s = (const Elf_Shdr *) ((const char *) s + e->e_shentsize))
if (s->sh_type == SHT_RELA)
{
const Elf_Rela *rel, *max;
for (rel = (const Elf_Rela *) ((const char *) e + s->sh_offset),
max = rel + s->sh_size / s->sh_entsize;
rel < max;
rel++)
if (ELF_R_TYPE (rel->r_info) == GRUB_ELF_R_PPC_REL24
|| ELF_R_TYPE (rel->r_info) == GRUB_ELF_R_PPC_PLTREL24)
(*tramp)++;
}
*tramp *= sizeof (struct trampoline);
return GRUB_ERR_NONE;
}
/* Relocate symbols. */
grub_err_t
grub_arch_dl_relocate_symbols (grub_dl_t mod, void *ehdr,
Elf_Shdr *s, grub_dl_segment_t seg)
{
Elf_Rela *rel, *max;
for (rel = (Elf_Rela *) ((char *) ehdr + s->sh_offset),
max = (Elf_Rela *) ((char *) rel + s->sh_size);
rel < max;
rel = (Elf_Rela *) ((char *) rel + s->sh_entsize))
{
Elf_Word *addr;
Elf_Sym *sym;
grub_uint32_t value;
if (seg->size < rel->r_offset)
return grub_error (GRUB_ERR_BAD_MODULE,
"reloc offset is out of the segment");
addr = (Elf_Word *) ((char *) seg->addr + rel->r_offset);
sym = (Elf_Sym *) ((char *) mod->symtab
+ mod->symsize * ELF_R_SYM (rel->r_info));
/* On the PPC the value does not have an explicit
addend, add it. */
value = sym->st_value + rel->r_addend;
switch (ELF_R_TYPE (rel->r_info))
{
case GRUB_ELF_R_PPC_ADDR16_LO:
*(Elf_Half *) addr = value;
break;
case GRUB_ELF_R_PPC_PLTREL24:
case GRUB_ELF_R_PPC_REL24:
{
Elf_Sword delta = value - (Elf_Word) addr;
if (delta << 6 >> 6 != delta)
{
struct trampoline *tptr = mod->trampptr;
grub_memcpy (tptr, &trampoline_template,
sizeof (*tptr));
delta = (grub_uint8_t *) tptr - (grub_uint8_t *) addr;
tptr->lis |= (((value) >> 16) & 0xffff);
tptr->ori |= ((value) & 0xffff);
mod->trampptr = tptr + 1;
}
if (delta << 6 >> 6 != delta)
return grub_error (GRUB_ERR_BAD_MODULE,
"relocation overflow");
*addr = (*addr & 0xfc000003) | (delta & 0x3fffffc);
break;
}
case GRUB_ELF_R_PPC_ADDR16_HA:
*(Elf_Half *) addr = (value + 0x8000) >> 16;
break;
case GRUB_ELF_R_PPC_ADDR32:
*addr = value;
break;
case GRUB_ELF_R_PPC_REL32:
*addr = value - (Elf_Word) addr;
break;
default:
return grub_error (GRUB_ERR_NOT_IMPLEMENTED_YET,
N_("relocation 0x%x is not implemented yet"),
ELF_R_TYPE (rel->r_info));
}
}
return GRUB_ERR_NONE;
}
|
