arch/mn10300/kernel/module.c

   1 /* MN10300 Kernel module helper routines
   2  *
   3  * Copyright (C) 2007, 2008 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         /* 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  */
  59 int module_frob_arch_sections(Elf_Ehdr *hdr,
  60                               Elf_Shdr *sechdrs,
  61                               char *secstrings,
  62                               struct module *mod)
  63 {
  64         return 0;
  65 }
  66
  67 static void reloc_put16(uint8_t *p, uint32_t val)
  68 {
  69         p[0] = val & 0xff;
  70         p[1] = (val >> 8) & 0xff;
  71 }
  72
  73 static void reloc_put24(uint8_t *p, uint32_t val)
  74 {
  75         reloc_put16(p, val);
  76         p[2] = (val >> 16) & 0xff;
  77 }
  78
  79 static void reloc_put32(uint8_t *p, uint32_t val)
  80 {
  81         reloc_put16(p, val);
  82         reloc_put16(p+2, val >> 16);
  83 }
  84
  85 /*
  86  * apply a REL relocation
  87  */
  88 int apply_relocate(Elf32_Shdr *sechdrs,
  89                    const char *strtab,
  90                    unsigned int symindex,
  91                    unsigned int relsec,
  92                    struct module *me)
  93 {
  94         printk(KERN_ERR "module %s: RELOCATION unsupported\n",
  95                me->name);
  96         return -ENOEXEC;
  97 }
  98
  99 /*
 100  * apply a RELA relocation
 101  */
 102 int apply_relocate_add(Elf32_Shdr *sechdrs,
 103                        const char *strtab,
 104                        unsigned int symindex,
 105                        unsigned int relsec,
 106                        struct module *me)
 107 {
 108         unsigned int i;
 109         Elf32_Rela *rel = (void *)sechdrs[relsec].sh_addr;
 110         Elf32_Sym *sym;
 111         Elf32_Addr relocation;
 112         uint8_t *location;
 113         uint32_t value;
 114
 115         DEBUGP("Applying relocate section %u to %u\n",
 116                relsec, sechdrs[relsec].sh_info);
 117
 118         for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rel); i++) {
 119                 /* this is where to make the change */
 120                 location = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr
 121                         + rel[i].r_offset;
 122
 123                 /* this is the symbol the relocation is referring to (note that
 124                  * all undefined symbols have been resolved by the caller) */
 125                 sym = (Elf32_Sym *)sechdrs[symindex].sh_addr
 126                         + ELF32_R_SYM(rel[i].r_info);
 127
 128                 /* this is the adjustment to be made */
 129                 relocation = sym->st_value + rel[i].r_addend;
 130
 131                 switch (ELF32_R_TYPE(rel[i].r_info)) {
 132                         /* for the first four relocation types, we simply
 133                          * store the adjustment at the location given */
 134                 case R_MN10300_32:
 135                         reloc_put32(location, relocation);
 136                         break;
 137                 case R_MN10300_24:
 138                         reloc_put24(location, relocation);
 139                         break;
 140                 case R_MN10300_16:
 141                         reloc_put16(location, relocation);
 142                         break;
 143                 case R_MN10300_8:
 144                         *location = relocation;
 145                         break;
 146
 147                         /* for the next three relocation types, we write the
 148                          * adjustment with the address subtracted over the
 149                          * value at the location given */
 150                 case R_MN10300_PCREL32:
 151                         value = relocation - (uint32_t) location;
 152                         reloc_put32(location, value);
 153                         break;
 154                 case R_MN10300_PCREL16:
 155                         value = relocation - (uint32_t) location;
 156                         reloc_put16(location, value);
 157                         break;
 158                 case R_MN10300_PCREL8:
 159                         *location = relocation - (uint32_t) location;
 160                         break;
 161
 162                 default:
 163                         printk(KERN_ERR "module %s: Unknown relocation: %u\n",
 164                                me->name, ELF32_R_TYPE(rel[i].r_info));
 165                         return -ENOEXEC;
 166                 }
 167         }
 168         return 0;
 169 }
 170
 171 /*
 172  * finish loading the module
 173  */
 174 int module_finalize(const Elf_Ehdr *hdr,
 175                     const Elf_Shdr *sechdrs,
 176                     struct module *me)
 177 {
 178         return module_bug_finalize(hdr, sechdrs, me);
 179 }
 180
 181 /*
 182  * finish clearing the module
 183  */
 184 void module_arch_cleanup(struct module *mod)
 185 {
 186         module_bug_cleanup(mod);
 187 }