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
 8int 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}