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d4c3e6e1 JY |
1 | /* |
2 | * livepatch.c - x86-specific Kernel Live Patching Core | |
3 | * | |
4 | * This program is free software; you can redistribute it and/or | |
5 | * modify it under the terms of the GNU General Public License | |
6 | * as published by the Free Software Foundation; either version 2 | |
7 | * of the License, or (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, see <http://www.gnu.org/licenses/>. | |
16 | */ | |
17 | ||
18 | #include <linux/module.h> | |
19 | #include <linux/kallsyms.h> | |
20 | #include <linux/livepatch.h> | |
21 | #include <asm/text-patching.h> | |
22 | ||
23 | /* Apply per-object alternatives. Based on x86 module_finalize() */ | |
24 | void arch_klp_init_object_loaded(struct klp_patch *patch, | |
25 | struct klp_object *obj) | |
26 | { | |
27 | int cnt; | |
28 | struct klp_modinfo *info; | |
29 | Elf_Shdr *s, *alt = NULL, *para = NULL; | |
30 | void *aseg, *pseg; | |
31 | const char *objname; | |
32 | char sec_objname[MODULE_NAME_LEN]; | |
33 | char secname[KSYM_NAME_LEN]; | |
34 | ||
35 | info = patch->mod->klp_info; | |
36 | objname = obj->name ? obj->name : "vmlinux"; | |
37 | ||
38 | /* See livepatch core code for BUILD_BUG_ON() explanation */ | |
39 | BUILD_BUG_ON(MODULE_NAME_LEN < 56 || KSYM_NAME_LEN != 128); | |
40 | ||
41 | for (s = info->sechdrs; s < info->sechdrs + info->hdr.e_shnum; s++) { | |
42 | /* Apply per-object .klp.arch sections */ | |
43 | cnt = sscanf(info->secstrings + s->sh_name, | |
44 | ".klp.arch.%55[^.].%127s", | |
45 | sec_objname, secname); | |
46 | if (cnt != 2) | |
47 | continue; | |
48 | if (strcmp(sec_objname, objname)) | |
49 | continue; | |
50 | if (!strcmp(".altinstructions", secname)) | |
51 | alt = s; | |
52 | if (!strcmp(".parainstructions", secname)) | |
53 | para = s; | |
54 | } | |
55 | ||
56 | if (alt) { | |
57 | aseg = (void *) alt->sh_addr; | |
58 | apply_alternatives(aseg, aseg + alt->sh_size); | |
59 | } | |
60 | ||
61 | if (para) { | |
62 | pseg = (void *) para->sh_addr; | |
63 | apply_paravirt(pseg, pseg + para->sh_size); | |
64 | } | |
65 | } |