1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * livepatch.c - x86-specific Kernel Live Patching Core
4 */
5
6 #include <linux/module.h>
7 #include <linux/kallsyms.h>
8 #include <linux/livepatch.h>
9 #include <asm/text-patching.h>
10
11 /* Apply per-object alternatives. Based on x86 module_finalize() */
arch_klp_init_object_loaded(struct klp_patch * patch,struct klp_object * obj)12 void arch_klp_init_object_loaded(struct klp_patch *patch,
13 struct klp_object *obj)
14 {
15 int cnt;
16 struct klp_modinfo *info;
17 Elf_Shdr *s, *alt = NULL, *para = NULL;
18 void *aseg, *pseg;
19 const char *objname;
20 char sec_objname[MODULE_NAME_LEN];
21 char secname[KSYM_NAME_LEN];
22
23 info = patch->mod->klp_info;
24 objname = obj->name ? obj->name : "vmlinux";
25
26 /* See livepatch core code for BUILD_BUG_ON() explanation */
27 BUILD_BUG_ON(MODULE_NAME_LEN < 56 || KSYM_NAME_LEN != 128);
28
29 for (s = info->sechdrs; s < info->sechdrs + info->hdr.e_shnum; s++) {
30 /* Apply per-object .klp.arch sections */
31 cnt = sscanf(info->secstrings + s->sh_name,
32 ".klp.arch.%55[^.].%127s",
33 sec_objname, secname);
34 if (cnt != 2)
35 continue;
36 if (strcmp(sec_objname, objname))
37 continue;
38 if (!strcmp(".altinstructions", secname))
39 alt = s;
40 if (!strcmp(".parainstructions", secname))
41 para = s;
42 }
43
44 if (alt) {
45 aseg = (void *) alt->sh_addr;
46 apply_alternatives(aseg, aseg + alt->sh_size);
47 }
48
49 if (para) {
50 pseg = (void *) para->sh_addr;
51 apply_paravirt(pseg, pseg + para->sh_size);
52 }
53 }
54
