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  */
  38 void *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  */
  48 void 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  */
  57 int module_frob_arch_sections(Elf_Ehdr *hdr,
  58                               Elf_Shdr *sechdrs,
  59                               char *secstrings,
  60                               struct module *mod)
  61 {
  62         return 0;
  63 }
  64
  65 static void reloc_put16(uint8_t *p, uint32_t val)
  66 {
  67         p[0] = val & 0xff;
  68         p[1] = (val >> 8) & 0xff;
  69 }
  70
  71 static void reloc_put24(uint8_t *p, uint32_t val)
  72 {
  73         reloc_put16(p, val);
  74         p[2] = (val >> 16) & 0xff;
  75 }
  76
  77 static 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  */
  86 int 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  */
 100 int 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  */
 205 int 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  */
 215 void module_arch_cleanup(struct module *mod)
 216 {
 217 }