blob: 772e7ad5dc299b785bc23181d1e9089cae3fa7ef [file] [log] [blame]
Amerigo Wang2d5bf282009-06-03 21:46:09 -04001/* Kernel module help for x86.
2 Copyright (C) 2001 Rusty Russell.
3
4 This program is free software; you can redistribute it and/or modify
5 it under the terms of the GNU General Public License as published by
6 the Free Software Foundation; either version 2 of the License, or
7 (at your option) any later version.
8
9 This program is distributed in the hope that it will be useful,
10 but WITHOUT ANY WARRANTY; without even the implied warranty of
11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 GNU General Public License for more details.
13
14 You should have received a copy of the GNU General Public License
15 along with this program; if not, write to the Free Software
16 Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
17*/
18#include <linux/moduleloader.h>
19#include <linux/elf.h>
20#include <linux/vmalloc.h>
21#include <linux/fs.h>
22#include <linux/string.h>
23#include <linux/kernel.h>
24#include <linux/bug.h>
25#include <linux/mm.h>
Tejun Heo5a0e3ad2010-03-24 17:04:11 +090026#include <linux/gfp.h>
Jason Barond430d3d2011-03-16 17:29:47 -040027#include <linux/jump_label.h>
Amerigo Wang2d5bf282009-06-03 21:46:09 -040028
Amerigo Wang2d5bf282009-06-03 21:46:09 -040029#include <asm/page.h>
30#include <asm/pgtable.h>
31
32#if 0
33#define DEBUGP printk
34#else
35#define DEBUGP(fmt...)
36#endif
37
Amerigo Wang0fdc83b2009-06-03 21:46:19 -040038void *module_alloc(unsigned long size)
39{
David Rientjesd0a21262011-01-13 15:46:02 -080040 if (PAGE_ALIGN(size) > MODULES_LEN)
Amerigo Wang0fdc83b2009-06-03 21:46:19 -040041 return NULL;
David Rientjesd0a21262011-01-13 15:46:02 -080042 return __vmalloc_node_range(size, 1, MODULES_VADDR, MODULES_END,
43 GFP_KERNEL | __GFP_HIGHMEM, PAGE_KERNEL_EXEC,
44 -1, __builtin_return_address(0));
Amerigo Wang0fdc83b2009-06-03 21:46:19 -040045}
Amerigo Wang0fdc83b2009-06-03 21:46:19 -040046
Amerigo Wang0fdc83b2009-06-03 21:46:19 -040047#ifdef CONFIG_X86_32
48int apply_relocate(Elf32_Shdr *sechdrs,
49 const char *strtab,
50 unsigned int symindex,
51 unsigned int relsec,
52 struct module *me)
53{
54 unsigned int i;
55 Elf32_Rel *rel = (void *)sechdrs[relsec].sh_addr;
56 Elf32_Sym *sym;
57 uint32_t *location;
58
59 DEBUGP("Applying relocate section %u to %u\n", relsec,
60 sechdrs[relsec].sh_info);
61 for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rel); i++) {
62 /* This is where to make the change */
63 location = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr
64 + rel[i].r_offset;
65 /* This is the symbol it is referring to. Note that all
66 undefined symbols have been resolved. */
67 sym = (Elf32_Sym *)sechdrs[symindex].sh_addr
68 + ELF32_R_SYM(rel[i].r_info);
69
70 switch (ELF32_R_TYPE(rel[i].r_info)) {
71 case R_386_32:
72 /* We add the value into the location given */
73 *location += sym->st_value;
74 break;
75 case R_386_PC32:
Geert Uytterhoeven2e76c282012-07-19 22:29:11 +020076 /* Add the value, subtract its position */
Amerigo Wang0fdc83b2009-06-03 21:46:19 -040077 *location += sym->st_value - (uint32_t)location;
78 break;
79 default:
80 printk(KERN_ERR "module %s: Unknown relocation: %u\n",
81 me->name, ELF32_R_TYPE(rel[i].r_info));
82 return -ENOEXEC;
83 }
84 }
85 return 0;
86}
Amerigo Wang0fdc83b2009-06-03 21:46:19 -040087#else /*X86_64*/
88int apply_relocate_add(Elf64_Shdr *sechdrs,
89 const char *strtab,
90 unsigned int symindex,
91 unsigned int relsec,
92 struct module *me)
93{
94 unsigned int i;
95 Elf64_Rela *rel = (void *)sechdrs[relsec].sh_addr;
96 Elf64_Sym *sym;
97 void *loc;
98 u64 val;
99
100 DEBUGP("Applying relocate section %u to %u\n", relsec,
101 sechdrs[relsec].sh_info);
102 for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rel); i++) {
103 /* This is where to make the change */
104 loc = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr
105 + rel[i].r_offset;
106
107 /* This is the symbol it is referring to. Note that all
108 undefined symbols have been resolved. */
109 sym = (Elf64_Sym *)sechdrs[symindex].sh_addr
110 + ELF64_R_SYM(rel[i].r_info);
111
112 DEBUGP("type %d st_value %Lx r_addend %Lx loc %Lx\n",
113 (int)ELF64_R_TYPE(rel[i].r_info),
114 sym->st_value, rel[i].r_addend, (u64)loc);
115
116 val = sym->st_value + rel[i].r_addend;
117
118 switch (ELF64_R_TYPE(rel[i].r_info)) {
119 case R_X86_64_NONE:
120 break;
121 case R_X86_64_64:
122 *(u64 *)loc = val;
123 break;
124 case R_X86_64_32:
125 *(u32 *)loc = val;
126 if (val != *(u32 *)loc)
127 goto overflow;
128 break;
129 case R_X86_64_32S:
130 *(s32 *)loc = val;
131 if ((s64)val != *(s32 *)loc)
132 goto overflow;
133 break;
134 case R_X86_64_PC32:
135 val -= (u64)loc;
136 *(u32 *)loc = val;
137#if 0
138 if ((s64)val != *(s32 *)loc)
139 goto overflow;
140#endif
141 break;
142 default:
143 printk(KERN_ERR "module %s: Unknown rela relocation: %llu\n",
144 me->name, ELF64_R_TYPE(rel[i].r_info));
145 return -ENOEXEC;
146 }
147 }
148 return 0;
149
150overflow:
151 printk(KERN_ERR "overflow in relocation type %d val %Lx\n",
152 (int)ELF64_R_TYPE(rel[i].r_info), val);
153 printk(KERN_ERR "`%s' likely not compiled with -mcmodel=kernel\n",
154 me->name);
155 return -ENOEXEC;
156}
Amerigo Wang0fdc83b2009-06-03 21:46:19 -0400157#endif
158
Amerigo Wang2d5bf282009-06-03 21:46:09 -0400159int module_finalize(const Elf_Ehdr *hdr,
160 const Elf_Shdr *sechdrs,
161 struct module *me)
162{
163 const Elf_Shdr *s, *text = NULL, *alt = NULL, *locks = NULL,
164 *para = NULL;
165 char *secstrings = (void *)hdr + sechdrs[hdr->e_shstrndx].sh_offset;
166
167 for (s = sechdrs; s < sechdrs + hdr->e_shnum; s++) {
168 if (!strcmp(".text", secstrings + s->sh_name))
169 text = s;
170 if (!strcmp(".altinstructions", secstrings + s->sh_name))
171 alt = s;
172 if (!strcmp(".smp_locks", secstrings + s->sh_name))
173 locks = s;
174 if (!strcmp(".parainstructions", secstrings + s->sh_name))
175 para = s;
176 }
177
178 if (alt) {
179 /* patch .altinstructions */
180 void *aseg = (void *)alt->sh_addr;
181 apply_alternatives(aseg, aseg + alt->sh_size);
182 }
183 if (locks && text) {
184 void *lseg = (void *)locks->sh_addr;
185 void *tseg = (void *)text->sh_addr;
186 alternatives_smp_module_add(me, me->name,
187 lseg, lseg + locks->sh_size,
188 tseg, tseg + text->sh_size);
189 }
190
191 if (para) {
192 void *pseg = (void *)para->sh_addr;
193 apply_paravirt(pseg, pseg + para->sh_size);
194 }
195
Jason Barond9f5ab72010-09-17 11:09:22 -0400196 /* make jump label nops */
197 jump_label_apply_nops(me);
198
Linus Torvalds53363772010-10-05 11:29:27 -0700199 return 0;
Amerigo Wang2d5bf282009-06-03 21:46:09 -0400200}
201
202void module_arch_cleanup(struct module *mod)
203{
204 alternatives_smp_module_del(mod);
Amerigo Wang2d5bf282009-06-03 21:46:09 -0400205}