int apply_relocate_add()

in kernel/module.c [83:181]

• 83 lines of code
• 12 McCabe index (conditional complexity)

int apply_relocate_add(Elf_Shdr *sechdrs,
		       const char *strtab,
		       unsigned int symindex,
		       unsigned int relsec,
		       struct module *me)
{
	unsigned int i;
	Elf_Rela *rel = (void *)sechdrs[relsec].sh_addr;
	Elf_Sym *sym;
	u8 *location;
	u32 *loc32;

	for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rel); i++) {
		Elf_Addr v;

		/* This is where to make the change */
		location = (u8 *)sechdrs[sechdrs[relsec].sh_info].sh_addr
			+ rel[i].r_offset;
		loc32 = (u32 *) location;

#ifdef CONFIG_SPARC64
		BUG_ON(((u64)location >> (u64)32) != (u64)0);
#endif /* CONFIG_SPARC64 */

		/* This is the symbol it is referring to.  Note that all
		   undefined symbols have been resolved.  */
		sym = (Elf_Sym *)sechdrs[symindex].sh_addr
			+ ELF_R_SYM(rel[i].r_info);
		v = sym->st_value + rel[i].r_addend;

		switch (ELF_R_TYPE(rel[i].r_info) & 0xff) {
		case R_SPARC_DISP32:
			v -= (Elf_Addr) location;
			*loc32 = v;
			break;
#ifdef CONFIG_SPARC64
		case R_SPARC_64:
			location[0] = v >> 56;
			location[1] = v >> 48;
			location[2] = v >> 40;
			location[3] = v >> 32;
			location[4] = v >> 24;
			location[5] = v >> 16;
			location[6] = v >>  8;
			location[7] = v >>  0;
			break;

		case R_SPARC_WDISP19:
			v -= (Elf_Addr) location;
			*loc32 = (*loc32 & ~0x7ffff) |
				((v >> 2) & 0x7ffff);
			break;

		case R_SPARC_OLO10:
			*loc32 = (*loc32 & ~0x1fff) |
				(((v & 0x3ff) +
				  (ELF_R_TYPE(rel[i].r_info) >> 8))
				 & 0x1fff);
			break;
#endif /* CONFIG_SPARC64 */

		case R_SPARC_32:
		case R_SPARC_UA32:
			location[0] = v >> 24;
			location[1] = v >> 16;
			location[2] = v >>  8;
			location[3] = v >>  0;
			break;

		case R_SPARC_WDISP30:
			v -= (Elf_Addr) location;
			*loc32 = (*loc32 & ~0x3fffffff) |
				((v >> 2) & 0x3fffffff);
			break;

		case R_SPARC_WDISP22:
			v -= (Elf_Addr) location;
			*loc32 = (*loc32 & ~0x3fffff) |
				((v >> 2) & 0x3fffff);
			break;

		case R_SPARC_LO10:
			*loc32 = (*loc32 & ~0x3ff) | (v & 0x3ff);
			break;

		case R_SPARC_HI22:
			*loc32 = (*loc32 & ~0x3fffff) |
				((v >> 10) & 0x3fffff);
			break;

		default:
			printk(KERN_ERR "module %s: Unknown relocation: %x\n",
			       me->name,
			       (int) (ELF_R_TYPE(rel[i].r_info) & 0xff));
			return -ENOEXEC;
		}
	}
	return 0;
}