/* MN10300 Kernel module helper routines
*
* Copyright (C) 2007, 2008, 2009 Red Hat, Inc. All Rights Reserved.
* Written by Mark Salter (msalter@redhat.com)
* - Derived from arch/i386/kernel/module.c
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public Licence as published by
* the Free Software Foundation; either version 2 of the Licence, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public Licence for more details.
*
* You should have received a copy of the GNU General Public Licence
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#include <linux/moduleloader.h>
#include <linux/elf.h>
#include <linux/vmalloc.h>
#include <linux/fs.h>
#include <linux/string.h>
#include <linux/kernel.h>
#include <linux/bug.h>
#if 0
#define DEBUGP printk
#else
#define DEBUGP(fmt, ...)
#endif
static void reloc_put16(uint8_t *p, uint32_t val)
{
p[0] = val & 0xff;
p[1] = (val >> 8) & 0xff;
}
static void reloc_put24(uint8_t *p, uint32_t val)
{
reloc_put16(p, val);
p[2] = (val >> 16) & 0xff;
}
static void reloc_put32(uint8_t *p, uint32_t val)
{
reloc_put16(p, val);
reloc_put16(p+2, val >> 16);
}
/*
* apply a RELA relocation
*/
int apply_relocate_add(Elf32_Shdr *sechdrs,
const char *strtab,
unsigned int symindex,
unsigned int relsec,
struct module *me)
{
unsigned int i, sym_diff_seen = 0;
Elf32_Rela *rel = (void *)sechdrs[relsec].sh_addr;
Elf32_Sym *sym;
Elf32_Addr relocation, sym_diff_val = 0;
uint8_t *location;
uint32_t value;
DEBUGP("Applying relocate section %u to %u\n",
relsec, sechdrs[relsec].sh_info);
for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rel); i++) {
/* this is where to make the change */
location = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr
+ rel[i].r_offset;
/* this is the symbol the relocation is referring to (note that
* all undefined symbols have been resolved by the caller) */
sym = (Elf32_Sym *)sechdrs[symindex].sh_addr
+ ELF32_R_SYM(rel[i].r_info);
/* this is the adjustment to be made */
relocation = sym->st_value + rel[i].r_addend;
if (sym_diff_seen) {
switch (ELF32_R_TYPE(rel[i].r_info)) {
case R_MN10300_32:
case R_MN10300_24:
case R_MN10300_16:
case R_MN10300_8:
relocation -= sym_diff_val;
sym_diff_seen = 0;
break;
default:
printk(KERN_ERR "module %s: Unexpected SYM_DIFF relocation: %u\n",
me->name, ELF32_R_TYPE(rel[i].r_info));
return -ENOEXEC;
}
}
switch (ELF32_R_TYPE(rel[i].r_info)) {
/* for the first four relocation types, we simply
* store the adjustment at the location given */
case R_MN10300_32:
reloc_put32(location, relocation);
break;
case R_MN10300_24:
reloc_put24(location, relocation);
break;
case R_MN10300_16:
reloc_put16(location, relocation);
break;
case R_MN10300_8:
*location = relocation;
break;
/* for the next three relocation types, we write the
* adjustment with the address subtracted over the
* value at the location given */
case R_MN10300_PCREL32:
value = relocation - (uint32_t) location;
reloc_put32(location, value);
break;
case R_MN10300_PCREL16:
value = relocation - (uint32_t) location;
reloc_put16(location, value);
break;
case R_MN10300_PCREL8:
*location = relocation - (uint32_t) location;
break;
case R_MN10300_SYM_DIFF:
/* This is used to adjust the next reloc as required
* by relaxation. */
sym_diff_seen = 1;
sym_diff_val = sym->st_value;
break;
case R_MN10300_ALIGN:
/* Just ignore the ALIGN relocs.
* Only interesting if kernel performed relaxation. */
continue;
default:
printk(KERN_ERR "module %s: Unknown relocation: %u\n",
me->name, ELF32_R_TYPE(rel[i].r_info));
return -ENOEXEC;
}
}
if (sym_diff_seen) {
printk(KERN_ERR "module %s: Nothing follows SYM_DIFF relocation: %u\n",
me->name, ELF32_R_TYPE(rel[i].r_info));
return -ENOEXEC;
}
return 0;
}
