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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 | |
35de5b06 | 34 | #include <asm/text-patching.h> |
2d5bf28f AW |
35 | #include <asm/page.h> |
36 | #include <asm/pgtable.h> | |
78cac48c | 37 | #include <asm/setup.h> |
2d5bf28f AW |
38 | |
39 | #if 0 | |
c767a54b JP |
40 | #define DEBUGP(fmt, ...) \ |
41 | printk(KERN_DEBUG fmt, ##__VA_ARGS__) | |
2d5bf28f | 42 | #else |
c767a54b JP |
43 | #define DEBUGP(fmt, ...) \ |
44 | do { \ | |
45 | if (0) \ | |
46 | printk(KERN_DEBUG fmt, ##__VA_ARGS__); \ | |
47 | } while (0) | |
2d5bf28f AW |
48 | #endif |
49 | ||
e2b32e67 KC |
50 | #ifdef CONFIG_RANDOMIZE_BASE |
51 | static unsigned long module_load_offset; | |
e2b32e67 | 52 | |
9dd721c6 KC |
53 | /* Mutex protects the module_load_offset. */ |
54 | static DEFINE_MUTEX(module_kaslr_mutex); | |
55 | ||
e2b32e67 KC |
56 | static unsigned long int get_module_load_offset(void) |
57 | { | |
78cac48c | 58 | if (kaslr_enabled()) { |
9dd721c6 | 59 | mutex_lock(&module_kaslr_mutex); |
e2b32e67 KC |
60 | /* |
61 | * Calculate the module_load_offset the first time this | |
62 | * code is called. Once calculated it stays the same until | |
63 | * reboot. | |
64 | */ | |
65 | if (module_load_offset == 0) | |
66 | module_load_offset = | |
67 | (get_random_int() % 1024 + 1) * PAGE_SIZE; | |
9dd721c6 | 68 | mutex_unlock(&module_kaslr_mutex); |
e2b32e67 KC |
69 | } |
70 | return module_load_offset; | |
71 | } | |
72 | #else | |
73 | static unsigned long int get_module_load_offset(void) | |
74 | { | |
75 | return 0; | |
76 | } | |
77 | #endif | |
78 | ||
0fdc83b9 AW |
79 | void *module_alloc(unsigned long size) |
80 | { | |
bebf56a1 AR |
81 | void *p; |
82 | ||
d0a21265 | 83 | if (PAGE_ALIGN(size) > MODULES_LEN) |
0fdc83b9 | 84 | return NULL; |
bebf56a1 AR |
85 | |
86 | p = __vmalloc_node_range(size, MODULE_ALIGN, | |
e2b32e67 | 87 | MODULES_VADDR + get_module_load_offset(), |
19809c2d | 88 | MODULES_END, GFP_KERNEL, |
cb9e3c29 | 89 | PAGE_KERNEL_EXEC, 0, NUMA_NO_NODE, |
e2b32e67 | 90 | __builtin_return_address(0)); |
bebf56a1 AR |
91 | if (p && (kasan_module_alloc(p, size) < 0)) { |
92 | vfree(p); | |
93 | return NULL; | |
94 | } | |
95 | ||
96 | return p; | |
0fdc83b9 | 97 | } |
0fdc83b9 | 98 | |
0fdc83b9 AW |
99 | #ifdef CONFIG_X86_32 |
100 | int apply_relocate(Elf32_Shdr *sechdrs, | |
101 | const char *strtab, | |
102 | unsigned int symindex, | |
103 | unsigned int relsec, | |
104 | struct module *me) | |
105 | { | |
106 | unsigned int i; | |
107 | Elf32_Rel *rel = (void *)sechdrs[relsec].sh_addr; | |
108 | Elf32_Sym *sym; | |
109 | uint32_t *location; | |
110 | ||
c767a54b JP |
111 | DEBUGP("Applying relocate section %u to %u\n", |
112 | relsec, sechdrs[relsec].sh_info); | |
0fdc83b9 AW |
113 | for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rel); i++) { |
114 | /* This is where to make the change */ | |
115 | location = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr | |
116 | + rel[i].r_offset; | |
117 | /* This is the symbol it is referring to. Note that all | |
118 | undefined symbols have been resolved. */ | |
119 | sym = (Elf32_Sym *)sechdrs[symindex].sh_addr | |
120 | + ELF32_R_SYM(rel[i].r_info); | |
121 | ||
122 | switch (ELF32_R_TYPE(rel[i].r_info)) { | |
123 | case R_386_32: | |
124 | /* We add the value into the location given */ | |
125 | *location += sym->st_value; | |
126 | break; | |
127 | case R_386_PC32: | |
2e76c283 | 128 | /* Add the value, subtract its position */ |
0fdc83b9 AW |
129 | *location += sym->st_value - (uint32_t)location; |
130 | break; | |
131 | default: | |
c767a54b | 132 | pr_err("%s: Unknown relocation: %u\n", |
0fdc83b9 AW |
133 | me->name, ELF32_R_TYPE(rel[i].r_info)); |
134 | return -ENOEXEC; | |
135 | } | |
136 | } | |
137 | return 0; | |
138 | } | |
0fdc83b9 AW |
139 | #else /*X86_64*/ |
140 | int apply_relocate_add(Elf64_Shdr *sechdrs, | |
141 | const char *strtab, | |
142 | unsigned int symindex, | |
143 | unsigned int relsec, | |
144 | struct module *me) | |
145 | { | |
146 | unsigned int i; | |
147 | Elf64_Rela *rel = (void *)sechdrs[relsec].sh_addr; | |
148 | Elf64_Sym *sym; | |
149 | void *loc; | |
150 | u64 val; | |
151 | ||
c767a54b JP |
152 | DEBUGP("Applying relocate section %u to %u\n", |
153 | relsec, sechdrs[relsec].sh_info); | |
0fdc83b9 AW |
154 | for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rel); i++) { |
155 | /* This is where to make the change */ | |
156 | loc = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr | |
157 | + rel[i].r_offset; | |
158 | ||
159 | /* This is the symbol it is referring to. Note that all | |
160 | undefined symbols have been resolved. */ | |
161 | sym = (Elf64_Sym *)sechdrs[symindex].sh_addr | |
162 | + ELF64_R_SYM(rel[i].r_info); | |
163 | ||
164 | DEBUGP("type %d st_value %Lx r_addend %Lx loc %Lx\n", | |
c767a54b JP |
165 | (int)ELF64_R_TYPE(rel[i].r_info), |
166 | sym->st_value, rel[i].r_addend, (u64)loc); | |
0fdc83b9 AW |
167 | |
168 | val = sym->st_value + rel[i].r_addend; | |
169 | ||
170 | switch (ELF64_R_TYPE(rel[i].r_info)) { | |
171 | case R_X86_64_NONE: | |
172 | break; | |
173 | case R_X86_64_64: | |
174 | *(u64 *)loc = val; | |
175 | break; | |
176 | case R_X86_64_32: | |
177 | *(u32 *)loc = val; | |
178 | if (val != *(u32 *)loc) | |
179 | goto overflow; | |
180 | break; | |
181 | case R_X86_64_32S: | |
182 | *(s32 *)loc = val; | |
183 | if ((s64)val != *(s32 *)loc) | |
184 | goto overflow; | |
185 | break; | |
186 | case R_X86_64_PC32: | |
187 | val -= (u64)loc; | |
188 | *(u32 *)loc = val; | |
189 | #if 0 | |
190 | if ((s64)val != *(s32 *)loc) | |
191 | goto overflow; | |
192 | #endif | |
193 | break; | |
194 | default: | |
c767a54b | 195 | pr_err("%s: Unknown rela relocation: %llu\n", |
0fdc83b9 AW |
196 | me->name, ELF64_R_TYPE(rel[i].r_info)); |
197 | return -ENOEXEC; | |
198 | } | |
199 | } | |
200 | return 0; | |
201 | ||
202 | overflow: | |
c767a54b | 203 | pr_err("overflow in relocation type %d val %Lx\n", |
0fdc83b9 | 204 | (int)ELF64_R_TYPE(rel[i].r_info), val); |
c767a54b | 205 | pr_err("`%s' likely not compiled with -mcmodel=kernel\n", |
0fdc83b9 AW |
206 | me->name); |
207 | return -ENOEXEC; | |
208 | } | |
0fdc83b9 AW |
209 | #endif |
210 | ||
2d5bf28f AW |
211 | int module_finalize(const Elf_Ehdr *hdr, |
212 | const Elf_Shdr *sechdrs, | |
213 | struct module *me) | |
214 | { | |
215 | const Elf_Shdr *s, *text = NULL, *alt = NULL, *locks = NULL, | |
216 | *para = NULL; | |
217 | char *secstrings = (void *)hdr + sechdrs[hdr->e_shstrndx].sh_offset; | |
218 | ||
219 | for (s = sechdrs; s < sechdrs + hdr->e_shnum; s++) { | |
220 | if (!strcmp(".text", secstrings + s->sh_name)) | |
221 | text = s; | |
222 | if (!strcmp(".altinstructions", secstrings + s->sh_name)) | |
223 | alt = s; | |
224 | if (!strcmp(".smp_locks", secstrings + s->sh_name)) | |
225 | locks = s; | |
226 | if (!strcmp(".parainstructions", secstrings + s->sh_name)) | |
227 | para = s; | |
228 | } | |
229 | ||
230 | if (alt) { | |
231 | /* patch .altinstructions */ | |
232 | void *aseg = (void *)alt->sh_addr; | |
233 | apply_alternatives(aseg, aseg + alt->sh_size); | |
234 | } | |
235 | if (locks && text) { | |
236 | void *lseg = (void *)locks->sh_addr; | |
237 | void *tseg = (void *)text->sh_addr; | |
238 | alternatives_smp_module_add(me, me->name, | |
239 | lseg, lseg + locks->sh_size, | |
240 | tseg, tseg + text->sh_size); | |
241 | } | |
242 | ||
243 | if (para) { | |
244 | void *pseg = (void *)para->sh_addr; | |
245 | apply_paravirt(pseg, pseg + para->sh_size); | |
246 | } | |
247 | ||
d9f5ab7b JB |
248 | /* make jump label nops */ |
249 | jump_label_apply_nops(me); | |
250 | ||
5336377d | 251 | return 0; |
2d5bf28f AW |
252 | } |
253 | ||
254 | void module_arch_cleanup(struct module *mod) | |
255 | { | |
256 | alternatives_smp_module_del(mod); | |
2d5bf28f | 257 | } |