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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> | |
26 | ||
27 | #include <asm/system.h> | |
28 | #include <asm/page.h> | |
29 | #include <asm/pgtable.h> | |
30 | ||
31 | #if 0 | |
32 | #define DEBUGP printk | |
33 | #else | |
34 | #define DEBUGP(fmt...) | |
35 | #endif | |
36 | ||
37 | void *module_alloc(unsigned long size) | |
38 | { | |
39 | struct vm_struct *area; | |
40 | ||
41 | if (!size) | |
42 | return NULL; | |
43 | size = PAGE_ALIGN(size); | |
44 | if (size > MODULES_LEN) | |
45 | return NULL; | |
46 | ||
47 | area = __get_vm_area(size, VM_ALLOC, MODULES_VADDR, MODULES_END); | |
48 | if (!area) | |
49 | return NULL; | |
50 | ||
51 | return __vmalloc_area(area, GFP_KERNEL | __GFP_HIGHMEM, | |
52 | PAGE_KERNEL_EXEC); | |
53 | } | |
54 | ||
55 | /* Free memory returned from module_alloc */ | |
56 | void module_free(struct module *mod, void *module_region) | |
57 | { | |
58 | vfree(module_region); | |
59 | } | |
60 | ||
61 | /* We don't need anything special. */ | |
62 | int module_frob_arch_sections(Elf_Ehdr *hdr, | |
63 | Elf_Shdr *sechdrs, | |
64 | char *secstrings, | |
65 | struct module *mod) | |
66 | { | |
67 | return 0; | |
68 | } | |
69 | ||
70 | #ifdef CONFIG_X86_32 | |
71 | int apply_relocate(Elf32_Shdr *sechdrs, | |
72 | const char *strtab, | |
73 | unsigned int symindex, | |
74 | unsigned int relsec, | |
75 | struct module *me) | |
76 | { | |
77 | unsigned int i; | |
78 | Elf32_Rel *rel = (void *)sechdrs[relsec].sh_addr; | |
79 | Elf32_Sym *sym; | |
80 | uint32_t *location; | |
81 | ||
82 | DEBUGP("Applying relocate section %u to %u\n", relsec, | |
83 | sechdrs[relsec].sh_info); | |
84 | for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rel); i++) { | |
85 | /* This is where to make the change */ | |
86 | location = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr | |
87 | + rel[i].r_offset; | |
88 | /* This is the symbol it is referring to. Note that all | |
89 | undefined symbols have been resolved. */ | |
90 | sym = (Elf32_Sym *)sechdrs[symindex].sh_addr | |
91 | + ELF32_R_SYM(rel[i].r_info); | |
92 | ||
93 | switch (ELF32_R_TYPE(rel[i].r_info)) { | |
94 | case R_386_32: | |
95 | /* We add the value into the location given */ | |
96 | *location += sym->st_value; | |
97 | break; | |
98 | case R_386_PC32: | |
99 | /* Add the value, subtract its postition */ | |
100 | *location += sym->st_value - (uint32_t)location; | |
101 | break; | |
102 | default: | |
103 | printk(KERN_ERR "module %s: Unknown relocation: %u\n", | |
104 | me->name, ELF32_R_TYPE(rel[i].r_info)); | |
105 | return -ENOEXEC; | |
106 | } | |
107 | } | |
108 | return 0; | |
109 | } | |
110 | ||
111 | int apply_relocate_add(Elf32_Shdr *sechdrs, | |
112 | const char *strtab, | |
113 | unsigned int symindex, | |
114 | unsigned int relsec, | |
115 | struct module *me) | |
116 | { | |
117 | printk(KERN_ERR "module %s: ADD RELOCATION unsupported\n", | |
118 | me->name); | |
119 | return -ENOEXEC; | |
120 | } | |
121 | #else /*X86_64*/ | |
122 | int apply_relocate_add(Elf64_Shdr *sechdrs, | |
123 | const char *strtab, | |
124 | unsigned int symindex, | |
125 | unsigned int relsec, | |
126 | struct module *me) | |
127 | { | |
128 | unsigned int i; | |
129 | Elf64_Rela *rel = (void *)sechdrs[relsec].sh_addr; | |
130 | Elf64_Sym *sym; | |
131 | void *loc; | |
132 | u64 val; | |
133 | ||
134 | DEBUGP("Applying relocate section %u to %u\n", relsec, | |
135 | sechdrs[relsec].sh_info); | |
136 | for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rel); i++) { | |
137 | /* This is where to make the change */ | |
138 | loc = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr | |
139 | + rel[i].r_offset; | |
140 | ||
141 | /* This is the symbol it is referring to. Note that all | |
142 | undefined symbols have been resolved. */ | |
143 | sym = (Elf64_Sym *)sechdrs[symindex].sh_addr | |
144 | + ELF64_R_SYM(rel[i].r_info); | |
145 | ||
146 | DEBUGP("type %d st_value %Lx r_addend %Lx loc %Lx\n", | |
147 | (int)ELF64_R_TYPE(rel[i].r_info), | |
148 | sym->st_value, rel[i].r_addend, (u64)loc); | |
149 | ||
150 | val = sym->st_value + rel[i].r_addend; | |
151 | ||
152 | switch (ELF64_R_TYPE(rel[i].r_info)) { | |
153 | case R_X86_64_NONE: | |
154 | break; | |
155 | case R_X86_64_64: | |
156 | *(u64 *)loc = val; | |
157 | break; | |
158 | case R_X86_64_32: | |
159 | *(u32 *)loc = val; | |
160 | if (val != *(u32 *)loc) | |
161 | goto overflow; | |
162 | break; | |
163 | case R_X86_64_32S: | |
164 | *(s32 *)loc = val; | |
165 | if ((s64)val != *(s32 *)loc) | |
166 | goto overflow; | |
167 | break; | |
168 | case R_X86_64_PC32: | |
169 | val -= (u64)loc; | |
170 | *(u32 *)loc = val; | |
171 | #if 0 | |
172 | if ((s64)val != *(s32 *)loc) | |
173 | goto overflow; | |
174 | #endif | |
175 | break; | |
176 | default: | |
177 | printk(KERN_ERR "module %s: Unknown rela relocation: %llu\n", | |
178 | me->name, ELF64_R_TYPE(rel[i].r_info)); | |
179 | return -ENOEXEC; | |
180 | } | |
181 | } | |
182 | return 0; | |
183 | ||
184 | overflow: | |
185 | printk(KERN_ERR "overflow in relocation type %d val %Lx\n", | |
186 | (int)ELF64_R_TYPE(rel[i].r_info), val); | |
187 | printk(KERN_ERR "`%s' likely not compiled with -mcmodel=kernel\n", | |
188 | me->name); | |
189 | return -ENOEXEC; | |
190 | } | |
191 | ||
192 | int apply_relocate(Elf_Shdr *sechdrs, | |
193 | const char *strtab, | |
194 | unsigned int symindex, | |
195 | unsigned int relsec, | |
196 | struct module *me) | |
197 | { | |
198 | printk(KERN_ERR "non add relocation not supported\n"); | |
199 | return -ENOSYS; | |
200 | } | |
201 | ||
202 | #endif | |
203 | ||
204 | int module_finalize(const Elf_Ehdr *hdr, | |
205 | const Elf_Shdr *sechdrs, | |
206 | struct module *me) | |
207 | { | |
208 | const Elf_Shdr *s, *text = NULL, *alt = NULL, *locks = NULL, | |
209 | *para = NULL; | |
210 | char *secstrings = (void *)hdr + sechdrs[hdr->e_shstrndx].sh_offset; | |
211 | ||
212 | for (s = sechdrs; s < sechdrs + hdr->e_shnum; s++) { | |
213 | if (!strcmp(".text", secstrings + s->sh_name)) | |
214 | text = s; | |
215 | if (!strcmp(".altinstructions", secstrings + s->sh_name)) | |
216 | alt = s; | |
217 | if (!strcmp(".smp_locks", secstrings + s->sh_name)) | |
218 | locks = s; | |
219 | if (!strcmp(".parainstructions", secstrings + s->sh_name)) | |
220 | para = s; | |
221 | } | |
222 | ||
223 | if (alt) { | |
224 | /* patch .altinstructions */ | |
225 | void *aseg = (void *)alt->sh_addr; | |
226 | apply_alternatives(aseg, aseg + alt->sh_size); | |
227 | } | |
228 | if (locks && text) { | |
229 | void *lseg = (void *)locks->sh_addr; | |
230 | void *tseg = (void *)text->sh_addr; | |
231 | alternatives_smp_module_add(me, me->name, | |
232 | lseg, lseg + locks->sh_size, | |
233 | tseg, tseg + text->sh_size); | |
234 | } | |
235 | ||
236 | if (para) { | |
237 | void *pseg = (void *)para->sh_addr; | |
238 | apply_paravirt(pseg, pseg + para->sh_size); | |
239 | } | |
240 | ||
241 | return module_bug_finalize(hdr, sechdrs, me); | |
242 | } | |
243 | ||
244 | void module_arch_cleanup(struct module *mod) | |
245 | { | |
246 | alternatives_smp_module_del(mod); | |
247 | module_bug_cleanup(mod); | |
248 | } |