LXR linux/arch/mn10300/kernel/module.c

   1/* MN10300 Kernel module helper routines
   2 *
   3 * Copyright (C) 2007, 2008, 2009 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}
  52
  53/*
  54 * allow the arch to fix up the section table
  55 * - we don't need anything special
  56 */
  57int module_frob_arch_sections(Elf_Ehdr *hdr,
  58                              Elf_Shdr *sechdrs,
  59                              char *secstrings,
  60                              struct module *mod)
  61{
  62        return 0;
  63}
  64
  65static void reloc_put16(uint8_t *p, uint32_t val)
  66{
  67        p[0] = val & 0xff;
  68        p[1] = (val >> 8) & 0xff;
  69}
  70
  71static void reloc_put24(uint8_t *p, uint32_t val)
  72{
  73        reloc_put16(p, val);
  74        p[2] = (val >> 16) & 0xff;
  75}
  76
  77static void reloc_put32(uint8_t *p, uint32_t val)
  78{
  79        reloc_put16(p, val);
  80        reloc_put16(p+2, val >> 16);
  81}
  82
  83/*
  84 * apply a REL relocation
  85 */
  86int apply_relocate(Elf32_Shdr *sechdrs,
  87                   const char *strtab,
  88                   unsigned int symindex,
  89                   unsigned int relsec,
  90                   struct module *me)
  91{
  92        printk(KERN_ERR "module %s: RELOCATION unsupported\n",
  93               me->name);
  94        return -ENOEXEC;
  95}
  96
  97/*
  98 * apply a RELA relocation
  99 */
 100int apply_relocate_add(Elf32_Shdr *sechdrs,
 101                       const char *strtab,
 102                       unsigned int symindex,
 103                       unsigned int relsec,
 104                       struct module *me)
 105{
 106        unsigned int i, sym_diff_seen = 0;
 107        Elf32_Rela *rel = (void *)sechdrs[relsec].sh_addr;
 108        Elf32_Sym *sym;
 109        Elf32_Addr relocation, sym_diff_val = 0;
 110        uint8_t *location;
 111        uint32_t value;
 112
 113        DEBUGP("Applying relocate section %u to %u\n",
 114               relsec, sechdrs[relsec].sh_info);
 115
 116        for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rel); i++) {
 117                /* this is where to make the change */
 118                location = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr
 119                        + rel[i].r_offset;
 120
 121                /* this is the symbol the relocation is referring to (note that
 122                 * all undefined symbols have been resolved by the caller) */
 123                sym = (Elf32_Sym *)sechdrs[symindex].sh_addr
 124                        + ELF32_R_SYM(rel[i].r_info);
 125
 126                /* this is the adjustment to be made */
 127                relocation = sym->st_value + rel[i].r_addend;
 128
 129                if (sym_diff_seen) {
 130                        switch (ELF32_R_TYPE(rel[i].r_info)) {
 131                        case R_MN10300_32:
 132                        case R_MN10300_24:
 133                        case R_MN10300_16:
 134                        case R_MN10300_8:
 135                                relocation -= sym_diff_val;
 136                                sym_diff_seen = 0;
 137                                break;
 138                        default:
 139                                printk(KERN_ERR "module %s: Unexpected SYM_DIFF relocation: %u\n",
 140                                       me->name, ELF32_R_TYPE(rel[i].r_info));
 141                                return -ENOEXEC;
 142                        }
 143                }
 144
 145                switch (ELF32_R_TYPE(rel[i].r_info)) {
 146                        /* for the first four relocation types, we simply
 147                         * store the adjustment at the location given */
 148                case R_MN10300_32:
 149                        reloc_put32(location, relocation);
 150                        break;
 151                case R_MN10300_24:
 152                        reloc_put24(location, relocation);
 153                        break;
 154                case R_MN10300_16:
 155                        reloc_put16(location, relocation);
 156                        break;
 157                case R_MN10300_8:
 158                        *location = relocation;
 159                        break;
 160
 161                        /* for the next three relocation types, we write the
 162                         * adjustment with the address subtracted over the
 163                         * value at the location given */
 164                case R_MN10300_PCREL32:
 165                        value = relocation - (uint32_t) location;
 166                        reloc_put32(location, value);
 167                        break;
 168                case R_MN10300_PCREL16:
 169                        value = relocation - (uint32_t) location;
 170                        reloc_put16(location, value);
 171                        break;
 172                case R_MN10300_PCREL8:
 173                        *location = relocation - (uint32_t) location;
 174                        break;
 175
 176                case R_MN10300_SYM_DIFF:
 177                        /* This is used to adjust the next reloc as required
 178                         * by relaxation. */
 179                        sym_diff_seen = 1;
 180                        sym_diff_val = sym->st_value;
 181                        break;
 182
 183                case R_MN10300_ALIGN:
 184                        /* Just ignore the ALIGN relocs.
 185                         * Only interesting if kernel performed relaxation. */
 186                        continue;
 187
 188                default:
 189                        printk(KERN_ERR "module %s: Unknown relocation: %u\n",
 190                               me->name, ELF32_R_TYPE(rel[i].r_info));
 191                        return -ENOEXEC;
 192                }
 193        }
 194        if (sym_diff_seen) {
 195                printk(KERN_ERR "module %s: Nothing follows SYM_DIFF relocation: %u\n",
 196                                       me->name, ELF32_R_TYPE(rel[i].r_info));
 197                return -ENOEXEC;
 198        }
 199        return 0;
 200}
 201
 202/*
 203 * finish loading the module
 204 */
 205int module_finalize(const Elf_Ehdr *hdr,
 206                    const Elf_Shdr *sechdrs,
 207                    struct module *me)
 208{
 209        return 0;
 210}
 211
 212/*
 213 * finish clearing the module
 214 */
 215void module_arch_cleanup(struct module *mod)
 216{
 217}
 218