Commit | Line | Data |
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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> | |
bebf56a1 | 27 | #include <linux/kasan.h> |
2d5bf28f AW |
28 | #include <linux/bug.h> |
29 | #include <linux/mm.h> | |
5a0e3ad6 | 30 | #include <linux/gfp.h> |
d430d3d7 | 31 | #include <linux/jump_label.h> |
e2b32e67 | 32 | #include <linux/random.h> |
2d5bf28f | 33 | |
2d5bf28f AW |
34 | #include <asm/page.h> |
35 | #include <asm/pgtable.h> | |
36 | ||
37 | #if 0 | |
c767a54b JP |
38 | #define DEBUGP(fmt, ...) \ |
39 | printk(KERN_DEBUG fmt, ##__VA_ARGS__) | |
2d5bf28f | 40 | #else |
c767a54b JP |
41 | #define DEBUGP(fmt, ...) \ |
42 | do { \ | |
43 | if (0) \ | |
44 | printk(KERN_DEBUG fmt, ##__VA_ARGS__); \ | |
45 | } while (0) | |
2d5bf28f AW |
46 | #endif |
47 | ||
e2b32e67 KC |
48 | #ifdef CONFIG_RANDOMIZE_BASE |
49 | static unsigned long module_load_offset; | |
69797daf | 50 | static int randomize_modules = 1; |
e2b32e67 | 51 | |
9dd721c6 KC |
52 | /* Mutex protects the module_load_offset. */ |
53 | static DEFINE_MUTEX(module_kaslr_mutex); | |
54 | ||
69797daf BP |
55 | static int __init parse_nokaslr(char *p) |
56 | { | |
57 | randomize_modules = 0; | |
58 | return 0; | |
59 | } | |
60 | early_param("nokaslr", parse_nokaslr); | |
61 | ||
e2b32e67 KC |
62 | static unsigned long int get_module_load_offset(void) |
63 | { | |
69797daf | 64 | if (randomize_modules) { |
9dd721c6 | 65 | mutex_lock(&module_kaslr_mutex); |
e2b32e67 KC |
66 | /* |
67 | * Calculate the module_load_offset the first time this | |
68 | * code is called. Once calculated it stays the same until | |
69 | * reboot. | |
70 | */ | |
71 | if (module_load_offset == 0) | |
72 | module_load_offset = | |
73 | (get_random_int() % 1024 + 1) * PAGE_SIZE; | |
9dd721c6 | 74 | mutex_unlock(&module_kaslr_mutex); |
e2b32e67 KC |
75 | } |
76 | return module_load_offset; | |
77 | } | |
78 | #else | |
79 | static unsigned long int get_module_load_offset(void) | |
80 | { | |
81 | return 0; | |
82 | } | |
83 | #endif | |
84 | ||
0fdc83b9 AW |
85 | void *module_alloc(unsigned long size) |
86 | { | |
bebf56a1 AR |
87 | void *p; |
88 | ||
d0a21265 | 89 | if (PAGE_ALIGN(size) > MODULES_LEN) |
0fdc83b9 | 90 | return NULL; |
bebf56a1 AR |
91 | |
92 | p = __vmalloc_node_range(size, MODULE_ALIGN, | |
e2b32e67 KC |
93 | MODULES_VADDR + get_module_load_offset(), |
94 | MODULES_END, GFP_KERNEL | __GFP_HIGHMEM, | |
cb9e3c29 | 95 | PAGE_KERNEL_EXEC, 0, NUMA_NO_NODE, |
e2b32e67 | 96 | __builtin_return_address(0)); |
bebf56a1 AR |
97 | if (p && (kasan_module_alloc(p, size) < 0)) { |
98 | vfree(p); | |
99 | return NULL; | |
100 | } | |
101 | ||
102 | return p; | |
0fdc83b9 | 103 | } |
0fdc83b9 | 104 | |
0fdc83b9 AW |
105 | #ifdef CONFIG_X86_32 |
106 | int apply_relocate(Elf32_Shdr *sechdrs, | |
107 | const char *strtab, | |
108 | unsigned int symindex, | |
109 | unsigned int relsec, | |
110 | struct module *me) | |
111 | { | |
112 | unsigned int i; | |
113 | Elf32_Rel *rel = (void *)sechdrs[relsec].sh_addr; | |
114 | Elf32_Sym *sym; | |
115 | uint32_t *location; | |
116 | ||
c767a54b JP |
117 | DEBUGP("Applying relocate section %u to %u\n", |
118 | relsec, sechdrs[relsec].sh_info); | |
0fdc83b9 AW |
119 | for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rel); i++) { |
120 | /* This is where to make the change */ | |
121 | location = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr | |
122 | + rel[i].r_offset; | |
123 | /* This is the symbol it is referring to. Note that all | |
124 | undefined symbols have been resolved. */ | |
125 | sym = (Elf32_Sym *)sechdrs[symindex].sh_addr | |
126 | + ELF32_R_SYM(rel[i].r_info); | |
127 | ||
128 | switch (ELF32_R_TYPE(rel[i].r_info)) { | |
129 | case R_386_32: | |
130 | /* We add the value into the location given */ | |
131 | *location += sym->st_value; | |
132 | break; | |
133 | case R_386_PC32: | |
2e76c283 | 134 | /* Add the value, subtract its position */ |
0fdc83b9 AW |
135 | *location += sym->st_value - (uint32_t)location; |
136 | break; | |
137 | default: | |
c767a54b | 138 | pr_err("%s: Unknown relocation: %u\n", |
0fdc83b9 AW |
139 | me->name, ELF32_R_TYPE(rel[i].r_info)); |
140 | return -ENOEXEC; | |
141 | } | |
142 | } | |
143 | return 0; | |
144 | } | |
0fdc83b9 AW |
145 | #else /*X86_64*/ |
146 | int apply_relocate_add(Elf64_Shdr *sechdrs, | |
147 | const char *strtab, | |
148 | unsigned int symindex, | |
149 | unsigned int relsec, | |
150 | struct module *me) | |
151 | { | |
152 | unsigned int i; | |
153 | Elf64_Rela *rel = (void *)sechdrs[relsec].sh_addr; | |
154 | Elf64_Sym *sym; | |
155 | void *loc; | |
156 | u64 val; | |
157 | ||
c767a54b JP |
158 | DEBUGP("Applying relocate section %u to %u\n", |
159 | relsec, sechdrs[relsec].sh_info); | |
0fdc83b9 AW |
160 | for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rel); i++) { |
161 | /* This is where to make the change */ | |
162 | loc = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr | |
163 | + rel[i].r_offset; | |
164 | ||
165 | /* This is the symbol it is referring to. Note that all | |
166 | undefined symbols have been resolved. */ | |
167 | sym = (Elf64_Sym *)sechdrs[symindex].sh_addr | |
168 | + ELF64_R_SYM(rel[i].r_info); | |
169 | ||
170 | DEBUGP("type %d st_value %Lx r_addend %Lx loc %Lx\n", | |
c767a54b JP |
171 | (int)ELF64_R_TYPE(rel[i].r_info), |
172 | sym->st_value, rel[i].r_addend, (u64)loc); | |
0fdc83b9 AW |
173 | |
174 | val = sym->st_value + rel[i].r_addend; | |
175 | ||
176 | switch (ELF64_R_TYPE(rel[i].r_info)) { | |
177 | case R_X86_64_NONE: | |
178 | break; | |
179 | case R_X86_64_64: | |
180 | *(u64 *)loc = val; | |
181 | break; | |
182 | case R_X86_64_32: | |
183 | *(u32 *)loc = val; | |
184 | if (val != *(u32 *)loc) | |
185 | goto overflow; | |
186 | break; | |
187 | case R_X86_64_32S: | |
188 | *(s32 *)loc = val; | |
189 | if ((s64)val != *(s32 *)loc) | |
190 | goto overflow; | |
191 | break; | |
192 | case R_X86_64_PC32: | |
193 | val -= (u64)loc; | |
194 | *(u32 *)loc = val; | |
195 | #if 0 | |
196 | if ((s64)val != *(s32 *)loc) | |
197 | goto overflow; | |
198 | #endif | |
199 | break; | |
200 | default: | |
c767a54b | 201 | pr_err("%s: Unknown rela relocation: %llu\n", |
0fdc83b9 AW |
202 | me->name, ELF64_R_TYPE(rel[i].r_info)); |
203 | return -ENOEXEC; | |
204 | } | |
205 | } | |
206 | return 0; | |
207 | ||
208 | overflow: | |
c767a54b | 209 | pr_err("overflow in relocation type %d val %Lx\n", |
0fdc83b9 | 210 | (int)ELF64_R_TYPE(rel[i].r_info), val); |
c767a54b | 211 | pr_err("`%s' likely not compiled with -mcmodel=kernel\n", |
0fdc83b9 AW |
212 | me->name); |
213 | return -ENOEXEC; | |
214 | } | |
0fdc83b9 AW |
215 | #endif |
216 | ||
2d5bf28f AW |
217 | int module_finalize(const Elf_Ehdr *hdr, |
218 | const Elf_Shdr *sechdrs, | |
219 | struct module *me) | |
220 | { | |
221 | const Elf_Shdr *s, *text = NULL, *alt = NULL, *locks = NULL, | |
222 | *para = NULL; | |
223 | char *secstrings = (void *)hdr + sechdrs[hdr->e_shstrndx].sh_offset; | |
224 | ||
225 | for (s = sechdrs; s < sechdrs + hdr->e_shnum; s++) { | |
226 | if (!strcmp(".text", secstrings + s->sh_name)) | |
227 | text = s; | |
228 | if (!strcmp(".altinstructions", secstrings + s->sh_name)) | |
229 | alt = s; | |
230 | if (!strcmp(".smp_locks", secstrings + s->sh_name)) | |
231 | locks = s; | |
232 | if (!strcmp(".parainstructions", secstrings + s->sh_name)) | |
233 | para = s; | |
234 | } | |
235 | ||
236 | if (alt) { | |
237 | /* patch .altinstructions */ | |
238 | void *aseg = (void *)alt->sh_addr; | |
239 | apply_alternatives(aseg, aseg + alt->sh_size); | |
240 | } | |
241 | if (locks && text) { | |
242 | void *lseg = (void *)locks->sh_addr; | |
243 | void *tseg = (void *)text->sh_addr; | |
244 | alternatives_smp_module_add(me, me->name, | |
245 | lseg, lseg + locks->sh_size, | |
246 | tseg, tseg + text->sh_size); | |
247 | } | |
248 | ||
249 | if (para) { | |
250 | void *pseg = (void *)para->sh_addr; | |
251 | apply_paravirt(pseg, pseg + para->sh_size); | |
252 | } | |
253 | ||
d9f5ab7b JB |
254 | /* make jump label nops */ |
255 | jump_label_apply_nops(me); | |
256 | ||
5336377d | 257 | return 0; |
2d5bf28f AW |
258 | } |
259 | ||
260 | void module_arch_cleanup(struct module *mod) | |
261 | { | |
262 | alternatives_smp_module_del(mod); | |
2d5bf28f | 263 | } |