1 // SPDX-License-Identifier: GPL-2.0
2 #include <linux/moduleloader.h>
3 #include <linux/elf.h>
4 #include <linux/vmalloc.h>
5 #include <linux/fs.h>
6 #include <linux/string.h>
7 #include <linux/kernel.h>
8
apply_relocate_add(Elf32_Shdr * sechdrs,const char * strtab,unsigned int symindex,unsigned int relsec,struct module * me)9 int apply_relocate_add(Elf32_Shdr *sechdrs,
10 const char *strtab,
11 unsigned int symindex,
12 unsigned int relsec,
13 struct module *me)
14 {
15 unsigned int i;
16 Elf32_Rela *rela = (void *)sechdrs[relsec].sh_addr;
17
18 pr_debug("Applying relocate section %u to %u\n", relsec,
19 sechdrs[relsec].sh_info);
20 for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rela); i++) {
21 /* This is where to make the change */
22 uint32_t *loc =
23 (uint32_t *)(sechdrs[sechdrs[relsec].sh_info].sh_addr
24 + rela[i].r_offset);
25 /* This is the symbol it is referring to. Note that all
26 undefined symbols have been resolved. */
27 Elf32_Sym *sym = (Elf32_Sym *)sechdrs[symindex].sh_addr
28 + ELF32_R_SYM(rela[i].r_info);
29 uint32_t v = sym->st_value + rela[i].r_addend;
30
31 switch (ELF32_R_TYPE(rela[i].r_info)) {
32 case R_H8_DIR24R8:
33 loc = (uint32_t *)((uint32_t)loc - 1);
34 *loc = (*loc & 0xff000000) | ((*loc & 0xffffff) + v);
35 break;
36 case R_H8_DIR24A8:
37 if (ELF32_R_SYM(rela[i].r_info))
38 *loc += v;
39 break;
40 case R_H8_DIR32:
41 case R_H8_DIR32A16:
42 *loc += v;
43 break;
44 case R_H8_PCREL16:
45 v -= (unsigned long)loc + 2;
46 if ((Elf32_Sword)v > 0x7fff ||
47 (Elf32_Sword)v < -(Elf32_Sword)0x8000)
48 goto overflow;
49 else
50 *(unsigned short *)loc = v;
51 break;
52 case R_H8_PCREL8:
53 v -= (unsigned long)loc + 1;
54 if ((Elf32_Sword)v > 0x7f ||
55 (Elf32_Sword)v < -(Elf32_Sword)0x80)
56 goto overflow;
57 else
58 *(unsigned char *)loc = v;
59 break;
60 default:
61 pr_err("module %s: Unknown relocation: %u\n",
62 me->name, ELF32_R_TYPE(rela[i].r_info));
63 return -ENOEXEC;
64 }
65 }
66 return 0;
67 overflow:
68 pr_err("module %s: relocation offset overflow: %08x\n",
69 me->name, rela[i].r_offset);
70 return -ENOEXEC;
71 }
72