release/src-rt-6.x.4708/linux/linux-2.6.36/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 #define DEBUGP(fmt, ...)
  30
  31 /*
  32  * allocate storage for a module
  33  */
  34 void *module_alloc(unsigned long size)
  35 {
  36         if (size == 0)
  37                 return NULL;
  38         return vmalloc_exec(size);
  39 }
  40
  41 /*
  42  * free memory returned from module_alloc()
  43  */
  44 void module_free(struct module *mod, void *module_region)
  45 {
  46         vfree(module_region);
  47 }
  48
  49 /*
  50  * allow the arch to fix up the section table
  51  * - we don't need anything special
  52  */
  53 int module_frob_arch_sections(Elf_Ehdr *hdr,
  54                               Elf_Shdr *sechdrs,
  55                               char *secstrings,
  56                               struct module *mod)
  57 {
  58         return 0;
  59 }
  60
  61 static void reloc_put16(uint8_t *p, uint32_t val)
  62 {
  63         p[0] = val & 0xff;
  64         p[1] = (val >> 8) & 0xff;
  65 }
  66
  67 static void reloc_put24(uint8_t *p, uint32_t val)
  68 {
  69         reloc_put16(p, val);
  70         p[2] = (val >> 16) & 0xff;
  71 }
  72
  73 static void reloc_put32(uint8_t *p, uint32_t val)
  74 {
  75         reloc_put16(p, val);
  76         reloc_put16(p+2, val >> 16);
  77 }
  78
  79 /*
  80  * apply a REL relocation
  81  */
  82 int apply_relocate(Elf32_Shdr *sechdrs,
  83                    const char *strtab,
  84                    unsigned int symindex,
  85                    unsigned int relsec,
  86                    struct module *me)
  87 {
  88         printk(KERN_ERR "module %s: RELOCATION unsupported\n",
  89                me->name);
  90         return -ENOEXEC;
  91 }
  92
  93 /*
  94  * apply a RELA relocation
  95  */
  96 int apply_relocate_add(Elf32_Shdr *sechdrs,
  97                        const char *strtab,
  98                        unsigned int symindex,
  99                        unsigned int relsec,
 100                        struct module *me)
 101 {
 102         unsigned int i, sym_diff_seen = 0;
 103         Elf32_Rela *rel = (void *)sechdrs[relsec].sh_addr;
 104         Elf32_Sym *sym;
 105         Elf32_Addr relocation, sym_diff_val = 0;
 106         uint8_t *location;
 107         uint32_t value;
 108
 109         DEBUGP("Applying relocate section %u to %u\n",
 110                relsec, sechdrs[relsec].sh_info);
 111
 112         for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rel); i++) {
 113                 /* this is where to make the change */
 114                 location = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr
 115                         + rel[i].r_offset;
 116
 117                 /* this is the symbol the relocation is referring to (note that
 118                  * all undefined symbols have been resolved by the caller) */
 119                 sym = (Elf32_Sym *)sechdrs[symindex].sh_addr
 120                         + ELF32_R_SYM(rel[i].r_info);
 121
 122                 /* this is the adjustment to be made */
 123                 relocation = sym->st_value + rel[i].r_addend;
 124
 125                 if (sym_diff_seen) {
 126                         switch (ELF32_R_TYPE(rel[i].r_info)) {
 127                         case R_MN10300_32:
 128                         case R_MN10300_24:
 129                         case R_MN10300_16:
 130                         case R_MN10300_8:
 131                                 relocation -= sym_diff_val;
 132                                 sym_diff_seen = 0;
 133                                 break;
 134                         default:
 135                                 printk(KERN_ERR "module %s: Unexpected SYM_DIFF relocation: %u\n",
 136                                        me->name, ELF32_R_TYPE(rel[i].r_info));
 137                                 return -ENOEXEC;
 138                         }
 139                 }
 140
 141                 switch (ELF32_R_TYPE(rel[i].r_info)) {
 142                         /* for the first four relocation types, we simply
 143                          * store the adjustment at the location given */
 144                 case R_MN10300_32:
 145                         reloc_put32(location, relocation);
 146                         break;
 147                 case R_MN10300_24:
 148                         reloc_put24(location, relocation);
 149                         break;
 150                 case R_MN10300_16:
 151                         reloc_put16(location, relocation);
 152                         break;
 153                 case R_MN10300_8:
 154                         *location = relocation;
 155                         break;
 156
 157                         /* for the next three relocation types, we write the
 158                          * adjustment with the address subtracted over the
 159                          * value at the location given */
 160                 case R_MN10300_PCREL32:
 161                         value = relocation - (uint32_t) location;
 162                         reloc_put32(location, value);
 163                         break;
 164                 case R_MN10300_PCREL16:
 165                         value = relocation - (uint32_t) location;
 166                         reloc_put16(location, value);
 167                         break;
 168                 case R_MN10300_PCREL8:
 169                         *location = relocation - (uint32_t) location;
 170                         break;
 171
 172                 case R_MN10300_SYM_DIFF:
 173                         /* This is used to adjust the next reloc as required
 174                          * by relaxation. */
 175                         sym_diff_seen = 1;
 176                         sym_diff_val = sym->st_value;
 177                         break;
 178
 179                 case R_MN10300_ALIGN:
 180                         /* Just ignore the ALIGN relocs.
 181                          * Only interesting if kernel performed relaxation. */
 182                         continue;
 183
 184                 default:
 185                         printk(KERN_ERR "module %s: Unknown relocation: %u\n",
 186                                me->name, ELF32_R_TYPE(rel[i].r_info));
 187                         return -ENOEXEC;
 188                 }
 189         }
 190         if (sym_diff_seen) {
 191                 printk(KERN_ERR "module %s: Nothing follows SYM_DIFF relocation: %u\n",
 192                                        me->name, ELF32_R_TYPE(rel[i].r_info));
 193                 return -ENOEXEC;
 194         }
 195         return 0;
 196 }
 197
 198 /*
 199  * finish loading the module
 200  */
 201 int module_finalize(const Elf_Ehdr *hdr,
 202                     const Elf_Shdr *sechdrs,
 203                     struct module *me)
 204 {
 205         return 0;
 206 }
 207
 208 /*
 209  * finish clearing the module
 210  */
 211 void module_arch_cleanup(struct module *mod)
 212 {
 213 }