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2d5bf28f AW |
1 | /* 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> | |
5a0e3ad6 | 26 | #include <linux/gfp.h> |
2d5bf28f AW |
27 | |
28 | #include <asm/system.h> | |
29 | #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 | ||
0fdc83b9 AW |
38 | void *module_alloc(unsigned long size) |
39 | { | |
40 | struct vm_struct *area; | |
41 | ||
42 | if (!size) | |
43 | return NULL; | |
44 | size = PAGE_ALIGN(size); | |
45 | if (size > MODULES_LEN) | |
46 | return NULL; | |
47 | ||
48 | area = __get_vm_area(size, VM_ALLOC, MODULES_VADDR, MODULES_END); | |
49 | if (!area) | |
50 | return NULL; | |
51 | ||
c398df30 AW |
52 | return __vmalloc_area(area, GFP_KERNEL | __GFP_HIGHMEM, |
53 | PAGE_KERNEL_EXEC); | |
0fdc83b9 | 54 | } |
0fdc83b9 | 55 | |
2d5bf28f AW |
56 | /* Free memory returned from module_alloc */ |
57 | void module_free(struct module *mod, void *module_region) | |
58 | { | |
59 | vfree(module_region); | |
2d5bf28f AW |
60 | } |
61 | ||
62 | /* We don't need anything special. */ | |
63 | int module_frob_arch_sections(Elf_Ehdr *hdr, | |
64 | Elf_Shdr *sechdrs, | |
65 | char *secstrings, | |
66 | struct module *mod) | |
67 | { | |
68 | return 0; | |
69 | } | |
70 | ||
0fdc83b9 AW |
71 | #ifdef CONFIG_X86_32 |
72 | int apply_relocate(Elf32_Shdr *sechdrs, | |
73 | const char *strtab, | |
74 | unsigned int symindex, | |
75 | unsigned int relsec, | |
76 | struct module *me) | |
77 | { | |
78 | unsigned int i; | |
79 | Elf32_Rel *rel = (void *)sechdrs[relsec].sh_addr; | |
80 | Elf32_Sym *sym; | |
81 | uint32_t *location; | |
82 | ||
83 | DEBUGP("Applying relocate section %u to %u\n", relsec, | |
84 | sechdrs[relsec].sh_info); | |
85 | for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rel); i++) { | |
86 | /* This is where to make the change */ | |
87 | location = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr | |
88 | + rel[i].r_offset; | |
89 | /* This is the symbol it is referring to. Note that all | |
90 | undefined symbols have been resolved. */ | |
91 | sym = (Elf32_Sym *)sechdrs[symindex].sh_addr | |
92 | + ELF32_R_SYM(rel[i].r_info); | |
93 | ||
94 | switch (ELF32_R_TYPE(rel[i].r_info)) { | |
95 | case R_386_32: | |
96 | /* We add the value into the location given */ | |
97 | *location += sym->st_value; | |
98 | break; | |
99 | case R_386_PC32: | |
100 | /* Add the value, subtract its postition */ | |
101 | *location += sym->st_value - (uint32_t)location; | |
102 | break; | |
103 | default: | |
104 | printk(KERN_ERR "module %s: Unknown relocation: %u\n", | |
105 | me->name, ELF32_R_TYPE(rel[i].r_info)); | |
106 | return -ENOEXEC; | |
107 | } | |
108 | } | |
109 | return 0; | |
110 | } | |
111 | ||
112 | int apply_relocate_add(Elf32_Shdr *sechdrs, | |
113 | const char *strtab, | |
114 | unsigned int symindex, | |
115 | unsigned int relsec, | |
116 | struct module *me) | |
117 | { | |
118 | printk(KERN_ERR "module %s: ADD RELOCATION unsupported\n", | |
119 | me->name); | |
120 | return -ENOEXEC; | |
121 | } | |
122 | #else /*X86_64*/ | |
123 | int apply_relocate_add(Elf64_Shdr *sechdrs, | |
124 | const char *strtab, | |
125 | unsigned int symindex, | |
126 | unsigned int relsec, | |
127 | struct module *me) | |
128 | { | |
129 | unsigned int i; | |
130 | Elf64_Rela *rel = (void *)sechdrs[relsec].sh_addr; | |
131 | Elf64_Sym *sym; | |
132 | void *loc; | |
133 | u64 val; | |
134 | ||
135 | DEBUGP("Applying relocate section %u to %u\n", relsec, | |
136 | sechdrs[relsec].sh_info); | |
137 | for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rel); i++) { | |
138 | /* This is where to make the change */ | |
139 | loc = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr | |
140 | + rel[i].r_offset; | |
141 | ||
142 | /* This is the symbol it is referring to. Note that all | |
143 | undefined symbols have been resolved. */ | |
144 | sym = (Elf64_Sym *)sechdrs[symindex].sh_addr | |
145 | + ELF64_R_SYM(rel[i].r_info); | |
146 | ||
147 | DEBUGP("type %d st_value %Lx r_addend %Lx loc %Lx\n", | |
148 | (int)ELF64_R_TYPE(rel[i].r_info), | |
149 | sym->st_value, rel[i].r_addend, (u64)loc); | |
150 | ||
151 | val = sym->st_value + rel[i].r_addend; | |
152 | ||
153 | switch (ELF64_R_TYPE(rel[i].r_info)) { | |
154 | case R_X86_64_NONE: | |
155 | break; | |
156 | case R_X86_64_64: | |
157 | *(u64 *)loc = val; | |
158 | break; | |
159 | case R_X86_64_32: | |
160 | *(u32 *)loc = val; | |
161 | if (val != *(u32 *)loc) | |
162 | goto overflow; | |
163 | break; | |
164 | case R_X86_64_32S: | |
165 | *(s32 *)loc = val; | |
166 | if ((s64)val != *(s32 *)loc) | |
167 | goto overflow; | |
168 | break; | |
169 | case R_X86_64_PC32: | |
170 | val -= (u64)loc; | |
171 | *(u32 *)loc = val; | |
172 | #if 0 | |
173 | if ((s64)val != *(s32 *)loc) | |
174 | goto overflow; | |
175 | #endif | |
176 | break; | |
177 | default: | |
178 | printk(KERN_ERR "module %s: Unknown rela relocation: %llu\n", | |
179 | me->name, ELF64_R_TYPE(rel[i].r_info)); | |
180 | return -ENOEXEC; | |
181 | } | |
182 | } | |
183 | return 0; | |
184 | ||
185 | overflow: | |
186 | printk(KERN_ERR "overflow in relocation type %d val %Lx\n", | |
187 | (int)ELF64_R_TYPE(rel[i].r_info), val); | |
188 | printk(KERN_ERR "`%s' likely not compiled with -mcmodel=kernel\n", | |
189 | me->name); | |
190 | return -ENOEXEC; | |
191 | } | |
192 | ||
193 | int apply_relocate(Elf_Shdr *sechdrs, | |
194 | const char *strtab, | |
195 | unsigned int symindex, | |
196 | unsigned int relsec, | |
197 | struct module *me) | |
198 | { | |
199 | printk(KERN_ERR "non add relocation not supported\n"); | |
200 | return -ENOSYS; | |
201 | } | |
202 | ||
203 | #endif | |
204 | ||
2d5bf28f AW |
205 | int module_finalize(const Elf_Ehdr *hdr, |
206 | const Elf_Shdr *sechdrs, | |
207 | struct module *me) | |
208 | { | |
209 | const Elf_Shdr *s, *text = NULL, *alt = NULL, *locks = NULL, | |
210 | *para = NULL; | |
211 | char *secstrings = (void *)hdr + sechdrs[hdr->e_shstrndx].sh_offset; | |
212 | ||
213 | for (s = sechdrs; s < sechdrs + hdr->e_shnum; s++) { | |
214 | if (!strcmp(".text", secstrings + s->sh_name)) | |
215 | text = s; | |
216 | if (!strcmp(".altinstructions", secstrings + s->sh_name)) | |
217 | alt = s; | |
218 | if (!strcmp(".smp_locks", secstrings + s->sh_name)) | |
219 | locks = s; | |
220 | if (!strcmp(".parainstructions", secstrings + s->sh_name)) | |
221 | para = s; | |
222 | } | |
223 | ||
224 | if (alt) { | |
225 | /* patch .altinstructions */ | |
226 | void *aseg = (void *)alt->sh_addr; | |
227 | apply_alternatives(aseg, aseg + alt->sh_size); | |
228 | } | |
229 | if (locks && text) { | |
230 | void *lseg = (void *)locks->sh_addr; | |
231 | void *tseg = (void *)text->sh_addr; | |
232 | alternatives_smp_module_add(me, me->name, | |
233 | lseg, lseg + locks->sh_size, | |
234 | tseg, tseg + text->sh_size); | |
235 | } | |
236 | ||
237 | if (para) { | |
238 | void *pseg = (void *)para->sh_addr; | |
239 | apply_paravirt(pseg, pseg + para->sh_size); | |
240 | } | |
241 | ||
d9f5ab7b JB |
242 | /* make jump label nops */ |
243 | jump_label_apply_nops(me); | |
244 | ||
2d5bf28f AW |
245 | return module_bug_finalize(hdr, sechdrs, me); |
246 | } | |
247 | ||
248 | void module_arch_cleanup(struct module *mod) | |
249 | { | |
250 | alternatives_smp_module_del(mod); | |
251 | module_bug_cleanup(mod); | |
252 | } |