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
14int 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}