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