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 | |
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> |
ee9f8fce | 38 | #include <asm/unwind.h> |
2d5bf28f AW |
39 | |
40 | #if 0 | |
c767a54b JP |
41 | #define DEBUGP(fmt, ...) \ |
42 | printk(KERN_DEBUG fmt, ##__VA_ARGS__) | |
2d5bf28f | 43 | #else |
c767a54b JP |
44 | #define DEBUGP(fmt, ...) \ |
45 | do { \ | |
46 | if (0) \ | |
47 | printk(KERN_DEBUG fmt, ##__VA_ARGS__); \ | |
48 | } while (0) | |
2d5bf28f AW |
49 | #endif |
50 | ||
e2b32e67 KC |
51 | #ifdef CONFIG_RANDOMIZE_BASE |
52 | static unsigned long module_load_offset; | |
e2b32e67 | 53 | |
9dd721c6 KC |
54 | /* Mutex protects the module_load_offset. */ |
55 | static DEFINE_MUTEX(module_kaslr_mutex); | |
56 | ||
e2b32e67 KC |
57 | static unsigned long int get_module_load_offset(void) |
58 | { | |
78cac48c | 59 | if (kaslr_enabled()) { |
9dd721c6 | 60 | mutex_lock(&module_kaslr_mutex); |
e2b32e67 KC |
61 | /* |
62 | * Calculate the module_load_offset the first time this | |
63 | * code is called. Once calculated it stays the same until | |
64 | * reboot. | |
65 | */ | |
66 | if (module_load_offset == 0) | |
67 | module_load_offset = | |
68 | (get_random_int() % 1024 + 1) * PAGE_SIZE; | |
9dd721c6 | 69 | mutex_unlock(&module_kaslr_mutex); |
e2b32e67 KC |
70 | } |
71 | return module_load_offset; | |
72 | } | |
73 | #else | |
74 | static unsigned long int get_module_load_offset(void) | |
75 | { | |
76 | return 0; | |
77 | } | |
78 | #endif | |
79 | ||
0fdc83b9 AW |
80 | void *module_alloc(unsigned long size) |
81 | { | |
bebf56a1 AR |
82 | void *p; |
83 | ||
d0a21265 | 84 | if (PAGE_ALIGN(size) > MODULES_LEN) |
0fdc83b9 | 85 | return NULL; |
bebf56a1 AR |
86 | |
87 | p = __vmalloc_node_range(size, MODULE_ALIGN, | |
e2b32e67 | 88 | MODULES_VADDR + get_module_load_offset(), |
19809c2d | 89 | MODULES_END, GFP_KERNEL, |
cb9e3c29 | 90 | PAGE_KERNEL_EXEC, 0, NUMA_NO_NODE, |
e2b32e67 | 91 | __builtin_return_address(0)); |
bebf56a1 AR |
92 | if (p && (kasan_module_alloc(p, size) < 0)) { |
93 | vfree(p); | |
94 | return NULL; | |
95 | } | |
96 | ||
97 | return p; | |
0fdc83b9 | 98 | } |
0fdc83b9 | 99 | |
0fdc83b9 AW |
100 | #ifdef CONFIG_X86_32 |
101 | int apply_relocate(Elf32_Shdr *sechdrs, | |
102 | const char *strtab, | |
103 | unsigned int symindex, | |
104 | unsigned int relsec, | |
105 | struct module *me) | |
106 | { | |
107 | unsigned int i; | |
108 | Elf32_Rel *rel = (void *)sechdrs[relsec].sh_addr; | |
109 | Elf32_Sym *sym; | |
110 | uint32_t *location; | |
111 | ||
c767a54b JP |
112 | DEBUGP("Applying relocate section %u to %u\n", |
113 | relsec, sechdrs[relsec].sh_info); | |
0fdc83b9 AW |
114 | for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rel); i++) { |
115 | /* This is where to make the change */ | |
116 | location = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr | |
117 | + rel[i].r_offset; | |
118 | /* This is the symbol it is referring to. Note that all | |
119 | undefined symbols have been resolved. */ | |
120 | sym = (Elf32_Sym *)sechdrs[symindex].sh_addr | |
121 | + ELF32_R_SYM(rel[i].r_info); | |
122 | ||
123 | switch (ELF32_R_TYPE(rel[i].r_info)) { | |
124 | case R_386_32: | |
125 | /* We add the value into the location given */ | |
126 | *location += sym->st_value; | |
127 | break; | |
128 | case R_386_PC32: | |
2e76c283 | 129 | /* Add the value, subtract its position */ |
0fdc83b9 AW |
130 | *location += sym->st_value - (uint32_t)location; |
131 | break; | |
132 | default: | |
c767a54b | 133 | pr_err("%s: Unknown relocation: %u\n", |
0fdc83b9 AW |
134 | me->name, ELF32_R_TYPE(rel[i].r_info)); |
135 | return -ENOEXEC; | |
136 | } | |
137 | } | |
138 | return 0; | |
139 | } | |
0fdc83b9 AW |
140 | #else /*X86_64*/ |
141 | int apply_relocate_add(Elf64_Shdr *sechdrs, | |
142 | const char *strtab, | |
143 | unsigned int symindex, | |
144 | unsigned int relsec, | |
145 | struct module *me) | |
146 | { | |
147 | unsigned int i; | |
148 | Elf64_Rela *rel = (void *)sechdrs[relsec].sh_addr; | |
149 | Elf64_Sym *sym; | |
150 | void *loc; | |
151 | u64 val; | |
152 | ||
c767a54b JP |
153 | DEBUGP("Applying relocate section %u to %u\n", |
154 | relsec, sechdrs[relsec].sh_info); | |
0fdc83b9 AW |
155 | for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rel); i++) { |
156 | /* This is where to make the change */ | |
157 | loc = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr | |
158 | + rel[i].r_offset; | |
159 | ||
160 | /* This is the symbol it is referring to. Note that all | |
161 | undefined symbols have been resolved. */ | |
162 | sym = (Elf64_Sym *)sechdrs[symindex].sh_addr | |
163 | + ELF64_R_SYM(rel[i].r_info); | |
164 | ||
165 | DEBUGP("type %d st_value %Lx r_addend %Lx loc %Lx\n", | |
c767a54b JP |
166 | (int)ELF64_R_TYPE(rel[i].r_info), |
167 | sym->st_value, rel[i].r_addend, (u64)loc); | |
0fdc83b9 AW |
168 | |
169 | val = sym->st_value + rel[i].r_addend; | |
170 | ||
171 | switch (ELF64_R_TYPE(rel[i].r_info)) { | |
172 | case R_X86_64_NONE: | |
173 | break; | |
174 | case R_X86_64_64: | |
eda9cec4 JP |
175 | if (*(u64 *)loc != 0) |
176 | goto invalid_relocation; | |
0fdc83b9 AW |
177 | *(u64 *)loc = val; |
178 | break; | |
179 | case R_X86_64_32: | |
eda9cec4 JP |
180 | if (*(u32 *)loc != 0) |
181 | goto invalid_relocation; | |
0fdc83b9 AW |
182 | *(u32 *)loc = val; |
183 | if (val != *(u32 *)loc) | |
184 | goto overflow; | |
185 | break; | |
186 | case R_X86_64_32S: | |
eda9cec4 JP |
187 | if (*(s32 *)loc != 0) |
188 | goto invalid_relocation; | |
0fdc83b9 AW |
189 | *(s32 *)loc = val; |
190 | if ((s64)val != *(s32 *)loc) | |
191 | goto overflow; | |
192 | break; | |
193 | case R_X86_64_PC32: | |
eda9cec4 JP |
194 | if (*(u32 *)loc != 0) |
195 | goto invalid_relocation; | |
0fdc83b9 AW |
196 | val -= (u64)loc; |
197 | *(u32 *)loc = val; | |
198 | #if 0 | |
199 | if ((s64)val != *(s32 *)loc) | |
200 | goto overflow; | |
201 | #endif | |
202 | break; | |
203 | default: | |
c767a54b | 204 | pr_err("%s: Unknown rela relocation: %llu\n", |
0fdc83b9 AW |
205 | me->name, ELF64_R_TYPE(rel[i].r_info)); |
206 | return -ENOEXEC; | |
207 | } | |
208 | } | |
209 | return 0; | |
210 | ||
eda9cec4 JP |
211 | invalid_relocation: |
212 | pr_err("x86/modules: Skipping invalid relocation target, existing value is nonzero for type %d, loc %p, val %Lx\n", | |
213 | (int)ELF64_R_TYPE(rel[i].r_info), loc, val); | |
214 | return -ENOEXEC; | |
215 | ||
0fdc83b9 | 216 | overflow: |
c767a54b | 217 | pr_err("overflow in relocation type %d val %Lx\n", |
0fdc83b9 | 218 | (int)ELF64_R_TYPE(rel[i].r_info), val); |
c767a54b | 219 | pr_err("`%s' likely not compiled with -mcmodel=kernel\n", |
0fdc83b9 AW |
220 | me->name); |
221 | return -ENOEXEC; | |
222 | } | |
0fdc83b9 AW |
223 | #endif |
224 | ||
2d5bf28f AW |
225 | int module_finalize(const Elf_Ehdr *hdr, |
226 | const Elf_Shdr *sechdrs, | |
227 | struct module *me) | |
228 | { | |
229 | const Elf_Shdr *s, *text = NULL, *alt = NULL, *locks = NULL, | |
ee9f8fce | 230 | *para = NULL, *orc = NULL, *orc_ip = NULL; |
2d5bf28f AW |
231 | char *secstrings = (void *)hdr + sechdrs[hdr->e_shstrndx].sh_offset; |
232 | ||
233 | for (s = sechdrs; s < sechdrs + hdr->e_shnum; s++) { | |
234 | if (!strcmp(".text", secstrings + s->sh_name)) | |
235 | text = s; | |
236 | if (!strcmp(".altinstructions", secstrings + s->sh_name)) | |
237 | alt = s; | |
238 | if (!strcmp(".smp_locks", secstrings + s->sh_name)) | |
239 | locks = s; | |
240 | if (!strcmp(".parainstructions", secstrings + s->sh_name)) | |
241 | para = s; | |
ee9f8fce JP |
242 | if (!strcmp(".orc_unwind", secstrings + s->sh_name)) |
243 | orc = s; | |
244 | if (!strcmp(".orc_unwind_ip", secstrings + s->sh_name)) | |
245 | orc_ip = s; | |
2d5bf28f AW |
246 | } |
247 | ||
248 | if (alt) { | |
249 | /* patch .altinstructions */ | |
250 | void *aseg = (void *)alt->sh_addr; | |
251 | apply_alternatives(aseg, aseg + alt->sh_size); | |
252 | } | |
253 | if (locks && text) { | |
254 | void *lseg = (void *)locks->sh_addr; | |
255 | void *tseg = (void *)text->sh_addr; | |
256 | alternatives_smp_module_add(me, me->name, | |
257 | lseg, lseg + locks->sh_size, | |
258 | tseg, tseg + text->sh_size); | |
259 | } | |
260 | ||
261 | if (para) { | |
262 | void *pseg = (void *)para->sh_addr; | |
263 | apply_paravirt(pseg, pseg + para->sh_size); | |
264 | } | |
265 | ||
d9f5ab7b JB |
266 | /* make jump label nops */ |
267 | jump_label_apply_nops(me); | |
268 | ||
ee9f8fce JP |
269 | if (orc && orc_ip) |
270 | unwind_module_init(me, (void *)orc_ip->sh_addr, orc_ip->sh_size, | |
271 | (void *)orc->sh_addr, orc->sh_size); | |
272 | ||
5336377d | 273 | return 0; |
2d5bf28f AW |
274 | } |
275 | ||
276 | void module_arch_cleanup(struct module *mod) | |
277 | { | |
278 | alternatives_smp_module_del(mod); | |
2d5bf28f | 279 | } |