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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 | */ | |
c767a54b JP |
18 | |
19 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt | |
20 | ||
2d5bf28f AW |
21 | #include <linux/moduleloader.h> |
22 | #include <linux/elf.h> | |
23 | #include <linux/vmalloc.h> | |
24 | #include <linux/fs.h> | |
25 | #include <linux/string.h> | |
26 | #include <linux/kernel.h> | |
27 | #include <linux/bug.h> | |
28 | #include <linux/mm.h> | |
5a0e3ad6 | 29 | #include <linux/gfp.h> |
d430d3d7 | 30 | #include <linux/jump_label.h> |
e2b32e67 | 31 | #include <linux/random.h> |
2d5bf28f | 32 | |
2d5bf28f AW |
33 | #include <asm/page.h> |
34 | #include <asm/pgtable.h> | |
35 | ||
36 | #if 0 | |
c767a54b JP |
37 | #define DEBUGP(fmt, ...) \ |
38 | printk(KERN_DEBUG fmt, ##__VA_ARGS__) | |
2d5bf28f | 39 | #else |
c767a54b JP |
40 | #define DEBUGP(fmt, ...) \ |
41 | do { \ | |
42 | if (0) \ | |
43 | printk(KERN_DEBUG fmt, ##__VA_ARGS__); \ | |
44 | } while (0) | |
2d5bf28f AW |
45 | #endif |
46 | ||
e2b32e67 KC |
47 | #ifdef CONFIG_RANDOMIZE_BASE |
48 | static unsigned long module_load_offset; | |
49 | static int randomize_modules = 1; | |
50 | ||
9dd721c6 KC |
51 | /* Mutex protects the module_load_offset. */ |
52 | static DEFINE_MUTEX(module_kaslr_mutex); | |
53 | ||
e2b32e67 KC |
54 | static int __init parse_nokaslr(char *p) |
55 | { | |
56 | randomize_modules = 0; | |
57 | return 0; | |
58 | } | |
59 | early_param("nokaslr", parse_nokaslr); | |
60 | ||
61 | static unsigned long int get_module_load_offset(void) | |
62 | { | |
63 | if (randomize_modules) { | |
9dd721c6 | 64 | mutex_lock(&module_kaslr_mutex); |
e2b32e67 KC |
65 | /* |
66 | * Calculate the module_load_offset the first time this | |
67 | * code is called. Once calculated it stays the same until | |
68 | * reboot. | |
69 | */ | |
70 | if (module_load_offset == 0) | |
71 | module_load_offset = | |
72 | (get_random_int() % 1024 + 1) * PAGE_SIZE; | |
9dd721c6 | 73 | mutex_unlock(&module_kaslr_mutex); |
e2b32e67 KC |
74 | } |
75 | return module_load_offset; | |
76 | } | |
77 | #else | |
78 | static unsigned long int get_module_load_offset(void) | |
79 | { | |
80 | return 0; | |
81 | } | |
82 | #endif | |
83 | ||
0fdc83b9 AW |
84 | void *module_alloc(unsigned long size) |
85 | { | |
d0a21265 | 86 | if (PAGE_ALIGN(size) > MODULES_LEN) |
0fdc83b9 | 87 | return NULL; |
e2b32e67 KC |
88 | return __vmalloc_node_range(size, 1, |
89 | MODULES_VADDR + get_module_load_offset(), | |
90 | MODULES_END, GFP_KERNEL | __GFP_HIGHMEM, | |
91 | PAGE_KERNEL_EXEC, NUMA_NO_NODE, | |
92 | __builtin_return_address(0)); | |
0fdc83b9 | 93 | } |
0fdc83b9 | 94 | |
0fdc83b9 AW |
95 | #ifdef CONFIG_X86_32 |
96 | int apply_relocate(Elf32_Shdr *sechdrs, | |
97 | const char *strtab, | |
98 | unsigned int symindex, | |
99 | unsigned int relsec, | |
100 | struct module *me) | |
101 | { | |
102 | unsigned int i; | |
103 | Elf32_Rel *rel = (void *)sechdrs[relsec].sh_addr; | |
104 | Elf32_Sym *sym; | |
105 | uint32_t *location; | |
106 | ||
c767a54b JP |
107 | DEBUGP("Applying relocate section %u to %u\n", |
108 | relsec, sechdrs[relsec].sh_info); | |
0fdc83b9 AW |
109 | for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rel); i++) { |
110 | /* This is where to make the change */ | |
111 | location = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr | |
112 | + rel[i].r_offset; | |
113 | /* This is the symbol it is referring to. Note that all | |
114 | undefined symbols have been resolved. */ | |
115 | sym = (Elf32_Sym *)sechdrs[symindex].sh_addr | |
116 | + ELF32_R_SYM(rel[i].r_info); | |
117 | ||
118 | switch (ELF32_R_TYPE(rel[i].r_info)) { | |
119 | case R_386_32: | |
120 | /* We add the value into the location given */ | |
121 | *location += sym->st_value; | |
122 | break; | |
123 | case R_386_PC32: | |
2e76c283 | 124 | /* Add the value, subtract its position */ |
0fdc83b9 AW |
125 | *location += sym->st_value - (uint32_t)location; |
126 | break; | |
127 | default: | |
c767a54b | 128 | pr_err("%s: Unknown relocation: %u\n", |
0fdc83b9 AW |
129 | me->name, ELF32_R_TYPE(rel[i].r_info)); |
130 | return -ENOEXEC; | |
131 | } | |
132 | } | |
133 | return 0; | |
134 | } | |
0fdc83b9 AW |
135 | #else /*X86_64*/ |
136 | int apply_relocate_add(Elf64_Shdr *sechdrs, | |
137 | const char *strtab, | |
138 | unsigned int symindex, | |
139 | unsigned int relsec, | |
140 | struct module *me) | |
141 | { | |
142 | unsigned int i; | |
143 | Elf64_Rela *rel = (void *)sechdrs[relsec].sh_addr; | |
144 | Elf64_Sym *sym; | |
145 | void *loc; | |
146 | u64 val; | |
147 | ||
c767a54b JP |
148 | DEBUGP("Applying relocate section %u to %u\n", |
149 | relsec, sechdrs[relsec].sh_info); | |
0fdc83b9 AW |
150 | for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rel); i++) { |
151 | /* This is where to make the change */ | |
152 | loc = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr | |
153 | + rel[i].r_offset; | |
154 | ||
155 | /* This is the symbol it is referring to. Note that all | |
156 | undefined symbols have been resolved. */ | |
157 | sym = (Elf64_Sym *)sechdrs[symindex].sh_addr | |
158 | + ELF64_R_SYM(rel[i].r_info); | |
159 | ||
160 | DEBUGP("type %d st_value %Lx r_addend %Lx loc %Lx\n", | |
c767a54b JP |
161 | (int)ELF64_R_TYPE(rel[i].r_info), |
162 | sym->st_value, rel[i].r_addend, (u64)loc); | |
0fdc83b9 AW |
163 | |
164 | val = sym->st_value + rel[i].r_addend; | |
165 | ||
166 | switch (ELF64_R_TYPE(rel[i].r_info)) { | |
167 | case R_X86_64_NONE: | |
168 | break; | |
169 | case R_X86_64_64: | |
170 | *(u64 *)loc = val; | |
171 | break; | |
172 | case R_X86_64_32: | |
173 | *(u32 *)loc = val; | |
174 | if (val != *(u32 *)loc) | |
175 | goto overflow; | |
176 | break; | |
177 | case R_X86_64_32S: | |
178 | *(s32 *)loc = val; | |
179 | if ((s64)val != *(s32 *)loc) | |
180 | goto overflow; | |
181 | break; | |
182 | case R_X86_64_PC32: | |
183 | val -= (u64)loc; | |
184 | *(u32 *)loc = val; | |
185 | #if 0 | |
186 | if ((s64)val != *(s32 *)loc) | |
187 | goto overflow; | |
188 | #endif | |
189 | break; | |
190 | default: | |
c767a54b | 191 | pr_err("%s: Unknown rela relocation: %llu\n", |
0fdc83b9 AW |
192 | me->name, ELF64_R_TYPE(rel[i].r_info)); |
193 | return -ENOEXEC; | |
194 | } | |
195 | } | |
196 | return 0; | |
197 | ||
198 | overflow: | |
c767a54b | 199 | pr_err("overflow in relocation type %d val %Lx\n", |
0fdc83b9 | 200 | (int)ELF64_R_TYPE(rel[i].r_info), val); |
c767a54b | 201 | pr_err("`%s' likely not compiled with -mcmodel=kernel\n", |
0fdc83b9 AW |
202 | me->name); |
203 | return -ENOEXEC; | |
204 | } | |
0fdc83b9 AW |
205 | #endif |
206 | ||
2d5bf28f AW |
207 | int module_finalize(const Elf_Ehdr *hdr, |
208 | const Elf_Shdr *sechdrs, | |
209 | struct module *me) | |
210 | { | |
211 | const Elf_Shdr *s, *text = NULL, *alt = NULL, *locks = NULL, | |
212 | *para = NULL; | |
213 | char *secstrings = (void *)hdr + sechdrs[hdr->e_shstrndx].sh_offset; | |
214 | ||
215 | for (s = sechdrs; s < sechdrs + hdr->e_shnum; s++) { | |
216 | if (!strcmp(".text", secstrings + s->sh_name)) | |
217 | text = s; | |
218 | if (!strcmp(".altinstructions", secstrings + s->sh_name)) | |
219 | alt = s; | |
220 | if (!strcmp(".smp_locks", secstrings + s->sh_name)) | |
221 | locks = s; | |
222 | if (!strcmp(".parainstructions", secstrings + s->sh_name)) | |
223 | para = s; | |
224 | } | |
225 | ||
226 | if (alt) { | |
227 | /* patch .altinstructions */ | |
228 | void *aseg = (void *)alt->sh_addr; | |
229 | apply_alternatives(aseg, aseg + alt->sh_size); | |
230 | } | |
231 | if (locks && text) { | |
232 | void *lseg = (void *)locks->sh_addr; | |
233 | void *tseg = (void *)text->sh_addr; | |
234 | alternatives_smp_module_add(me, me->name, | |
235 | lseg, lseg + locks->sh_size, | |
236 | tseg, tseg + text->sh_size); | |
237 | } | |
238 | ||
239 | if (para) { | |
240 | void *pseg = (void *)para->sh_addr; | |
241 | apply_paravirt(pseg, pseg + para->sh_size); | |
242 | } | |
243 | ||
d9f5ab7b JB |
244 | /* make jump label nops */ |
245 | jump_label_apply_nops(me); | |
246 | ||
5336377d | 247 | return 0; |
2d5bf28f AW |
248 | } |
249 | ||
250 | void module_arch_cleanup(struct module *mod) | |
251 | { | |
252 | alternatives_smp_module_del(mod); | |
2d5bf28f | 253 | } |