module.c
1.97 KB
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#include <linux/moduleloader.h>
#include <linux/elf.h>
#include <linux/vmalloc.h>
#include <linux/fs.h>
#include <linux/string.h>
#include <linux/kernel.h>
#if 0
#define DEBUGP printk
#else
#define DEBUGP(fmt...)
#endif
int apply_relocate_add(Elf32_Shdr *sechdrs,
const char *strtab,
unsigned int symindex,
unsigned int relsec,
struct module *me)
{
unsigned int i;
Elf32_Rela *rela = (void *)sechdrs[relsec].sh_addr;
DEBUGP("Applying relocate section %u to %u\n", relsec,
sechdrs[relsec].sh_info);
for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rela); i++) {
/* This is where to make the change */
uint32_t *loc = (uint32_t *)(sechdrs[sechdrs[relsec].sh_info].sh_addr
+ rela[i].r_offset);
/* This is the symbol it is referring to. Note that all
undefined symbols have been resolved. */
Elf32_Sym *sym = (Elf32_Sym *)sechdrs[symindex].sh_addr
+ ELF32_R_SYM(rela[i].r_info);
uint32_t v = sym->st_value + rela[i].r_addend;
switch (ELF32_R_TYPE(rela[i].r_info)) {
case R_H8_DIR24R8:
loc = (uint32_t *)((uint32_t)loc - 1);
*loc = (*loc & 0xff000000) | ((*loc & 0xffffff) + v);
break;
case R_H8_DIR24A8:
if (ELF32_R_SYM(rela[i].r_info))
*loc += v;
break;
case R_H8_DIR32:
case R_H8_DIR32A16:
*loc += v;
break;
case R_H8_PCREL16:
v -= (unsigned long)loc + 2;
if ((Elf32_Sword)v > 0x7fff ||
(Elf32_Sword)v < -(Elf32_Sword)0x8000)
goto overflow;
else
*(unsigned short *)loc = v;
break;
case R_H8_PCREL8:
v -= (unsigned long)loc + 1;
if ((Elf32_Sword)v > 0x7f ||
(Elf32_Sword)v < -(Elf32_Sword)0x80)
goto overflow;
else
*(unsigned char *)loc = v;
break;
default:
printk(KERN_ERR "module %s: Unknown relocation: %u\n",
me->name, ELF32_R_TYPE(rela[i].r_info));
return -ENOEXEC;
}
}
return 0;
overflow:
printk(KERN_ERR "module %s: relocation offset overflow: %08x\n",
me->name, rela[i].r_offset);
return -ENOEXEC;
}