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