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
8 #if 0
9 #define DEBUGP printk
10 #else
11 #define DEBUGP(fmt...)
12 #endif
13
apply_relocate_add(Elf32_Shdr * sechdrs,const char * strtab,unsigned int symindex,unsigned int relsec,struct module * me)14 int apply_relocate_add(Elf32_Shdr *sechdrs,
15 const char *strtab,
16 unsigned int symindex,
17 unsigned int relsec,
18 struct module *me)
19 {
20 unsigned int i;
21 Elf32_Rela *rela = (void *)sechdrs[relsec].sh_addr;
22
23 DEBUGP("Applying relocate section %u to %u\n", relsec,
24 sechdrs[relsec].sh_info);
25 for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rela); i++) {
26 /* This is where to make the change */
27 uint32_t *loc = (uint32_t *)(sechdrs[sechdrs[relsec].sh_info].sh_addr
28 + rela[i].r_offset);
29 /* This is the symbol it is referring to. Note that all
30 undefined symbols have been resolved. */
31 Elf32_Sym *sym = (Elf32_Sym *)sechdrs[symindex].sh_addr
32 + ELF32_R_SYM(rela[i].r_info);
33 uint32_t v = sym->st_value + rela[i].r_addend;
34
35 switch (ELF32_R_TYPE(rela[i].r_info)) {
36 case R_H8_DIR24R8:
37 loc = (uint32_t *)((uint32_t)loc - 1);
38 *loc = (*loc & 0xff000000) | ((*loc & 0xffffff) + v);
39 break;
40 case R_H8_DIR24A8:
41 if (ELF32_R_SYM(rela[i].r_info))
42 *loc += v;
43 break;
44 case R_H8_DIR32:
45 case R_H8_DIR32A16:
46 *loc += v;
47 break;
48 case R_H8_PCREL16:
49 v -= (unsigned long)loc + 2;
50 if ((Elf32_Sword)v > 0x7fff ||
51 (Elf32_Sword)v < -(Elf32_Sword)0x8000)
52 goto overflow;
53 else
54 *(unsigned short *)loc = v;
55 break;
56 case R_H8_PCREL8:
57 v -= (unsigned long)loc + 1;
58 if ((Elf32_Sword)v > 0x7f ||
59 (Elf32_Sword)v < -(Elf32_Sword)0x80)
60 goto overflow;
61 else
62 *(unsigned char *)loc = v;
63 break;
64 default:
65 printk(KERN_ERR "module %s: Unknown relocation: %u\n",
66 me->name, ELF32_R_TYPE(rela[i].r_info));
67 return -ENOEXEC;
68 }
69 }
70 return 0;
71 overflow:
72 printk(KERN_ERR "module %s: relocation offset overflow: %08x\n",
73 me->name, rela[i].r_offset);
74 return -ENOEXEC;
75 }
76