linux/arch/mn10300/kernel/module.c
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   1/* MN10300 Kernel module helper routines
   2 *
   3 * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
   4 * Written by Mark Salter (msalter@redhat.com)
   5 * - Derived from arch/i386/kernel/module.c
   6 *
   7 * This program is free software; you can redistribute it and/or modify
   8 * it under the terms of the GNU General Public Licence as published by
   9 * the Free Software Foundation; either version 2 of the Licence, or
  10 * (at your option) any later version.
  11 *
  12 * This program is distributed in the hope that it will be useful,
  13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15 * GNU General Public Licence for more details.
  16 *
  17 * You should have received a copy of the GNU General Public Licence
  18 * along with this program; if not, write to the Free Software
  19 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  20 */
  21#include <linux/moduleloader.h>
  22#include <linux/elf.h>
  23#include <linux/vmalloc.h>
  24#include <linux/fs.h>
  25#include <linux/string.h>
  26#include <linux/kernel.h>
  27#include <linux/bug.h>
  28
  29#if 0
  30#define DEBUGP printk
  31#else
  32#define DEBUGP(fmt, ...)
  33#endif
  34
  35/*
  36 * allocate storage for a module
  37 */
  38void *module_alloc(unsigned long size)
  39{
  40        if (size == 0)
  41                return NULL;
  42        return vmalloc_exec(size);
  43}
  44
  45/*
  46 * free memory returned from module_alloc()
  47 */
  48void module_free(struct module *mod, void *module_region)
  49{
  50        vfree(module_region);
  51        /* FIXME: If module_region == mod->init_region, trim exception
  52         * table entries. */
  53}
  54
  55/*
  56 * allow the arch to fix up the section table
  57 * - we don't need anything special
  58 */
  59int module_frob_arch_sections(Elf_Ehdr *hdr,
  60                              Elf_Shdr *sechdrs,
  61                              char *secstrings,
  62                              struct module *mod)
  63{
  64        return 0;
  65}
  66
  67static uint32_t reloc_get16(uint8_t *p)
  68{
  69        return p[0] | (p[1] << 8);
  70}
  71
  72static uint32_t reloc_get24(uint8_t *p)
  73{
  74        return reloc_get16(p) | (p[2] << 16);
  75}
  76
  77static uint32_t reloc_get32(uint8_t *p)
  78{
  79        return reloc_get16(p) | (reloc_get16(p+2) << 16);
  80}
  81
  82static void reloc_put16(uint8_t *p, uint32_t val)
  83{
  84        p[0] = val & 0xff;
  85        p[1] = (val >> 8) & 0xff;
  86}
  87
  88static void reloc_put24(uint8_t *p, uint32_t val)
  89{
  90        reloc_put16(p, val);
  91        p[2] = (val >> 16) & 0xff;
  92}
  93
  94static void reloc_put32(uint8_t *p, uint32_t val)
  95{
  96        reloc_put16(p, val);
  97        reloc_put16(p+2, val >> 16);
  98}
  99
 100/*
 101 * apply a REL relocation
 102 */
 103int apply_relocate(Elf32_Shdr *sechdrs,
 104                   const char *strtab,
 105                   unsigned int symindex,
 106                   unsigned int relsec,
 107                   struct module *me)
 108{
 109        printk(KERN_ERR "module %s: RELOCATION unsupported\n",
 110               me->name);
 111        return -ENOEXEC;
 112}
 113
 114/*
 115 * apply a RELA relocation
 116 */
 117int apply_relocate_add(Elf32_Shdr *sechdrs,
 118                       const char *strtab,
 119                       unsigned int symindex,
 120                       unsigned int relsec,
 121                       struct module *me)
 122{
 123        unsigned int i;
 124        Elf32_Rela *rel = (void *)sechdrs[relsec].sh_addr;
 125        Elf32_Sym *sym;
 126        Elf32_Addr relocation;
 127        uint8_t *location;
 128        uint32_t value;
 129
 130        DEBUGP("Applying relocate section %u to %u\n",
 131               relsec, sechdrs[relsec].sh_info);
 132
 133        for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rel); i++) {
 134                /* this is where to make the change */
 135                location = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr
 136                        + rel[i].r_offset;
 137
 138                /* this is the symbol the relocation is referring to (note that
 139                 * all undefined symbols have been resolved by the caller) */
 140                sym = (Elf32_Sym *)sechdrs[symindex].sh_addr
 141                        + ELF32_R_SYM(rel[i].r_info);
 142
 143                /* this is the adjustment to be made */
 144                relocation = sym->st_value + rel[i].r_addend;
 145
 146                switch (ELF32_R_TYPE(rel[i].r_info)) {
 147                        /* for the first four relocation types, we add the
 148                         * adjustment into the value at the location given */
 149                case R_MN10300_32:
 150                        value = reloc_get32(location);
 151                        value += relocation;
 152                        reloc_put32(location, value);
 153                        break;
 154                case R_MN10300_24:
 155                        value = reloc_get24(location);
 156                        value += relocation;
 157                        reloc_put24(location, value);
 158                        break;
 159                case R_MN10300_16:
 160                        value = reloc_get16(location);
 161                        value += relocation;
 162                        reloc_put16(location, value);
 163                        break;
 164                case R_MN10300_8:
 165                        *location += relocation;
 166                        break;
 167
 168                        /* for the next three relocation types, we write the
 169                         * adjustment with the address subtracted over the
 170                         * value at the location given */
 171                case R_MN10300_PCREL32:
 172                        value = relocation - (uint32_t) location;
 173                        reloc_put32(location, value);
 174                        break;
 175                case R_MN10300_PCREL16:
 176                        value = relocation - (uint32_t) location;
 177                        reloc_put16(location, value);
 178                        break;
 179                case R_MN10300_PCREL8:
 180                        *location = relocation - (uint32_t) location;
 181                        break;
 182
 183                default:
 184                        printk(KERN_ERR "module %s: Unknown relocation: %u\n",
 185                               me->name, ELF32_R_TYPE(rel[i].r_info));
 186                        return -ENOEXEC;
 187                }
 188        }
 189        return 0;
 190}
 191
 192/*
 193 * finish loading the module
 194 */
 195int module_finalize(const Elf_Ehdr *hdr,
 196                    const Elf_Shdr *sechdrs,
 197                    struct module *me)
 198{
 199        return module_bug_finalize(hdr, sechdrs, me);
 200}
 201
 202/*
 203 * finish clearing the module
 204 */
 205void module_arch_cleanup(struct module *mod)
 206{
 207        module_bug_cleanup(mod);
 208}
 209