Linux Kernel  3.7.1
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module.c
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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 
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 }