arch/mn10300/kernel/module.c

   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
  28 #if 0
  29 #define DEBUGP printk
  30 #else
  31 #define DEBUGP(fmt, ...)
  32 #endif
  33
  34 /*
  35  * allocate storage for a module
  36  */
  37 void *module_alloc(unsigned long size)
  38 {
  39         if (size == 0)
  40                 return NULL;
  41         return vmalloc_exec(size);
  42 }
  43
  44 /*
  45  * free memory returned from module_alloc()
  46  */
  47 void module_free(struct module *mod, void *module_region)
  48 {
  49         vfree(module_region);
  50         /* FIXME: If module_region == mod->init_region, trim exception
  51          * table entries. */
  52 }
  53
  54 /*
  55  * allow the arch to fix up the section table
  56  * - we don't need anything special
  57  */
  58 int module_frob_arch_sections(Elf_Ehdr *hdr,
  59                               Elf_Shdr *sechdrs,
  60                               char *secstrings,
  61                               struct module *mod)
  62 {
  63         return 0;
  64 }
  65
  66 static uint32_t reloc_get16(uint8_t *p)
  67 {
  68         return p[0] | (p[1] << 8);
  69 }
  70
  71 static uint32_t reloc_get24(uint8_t *p)
  72 {
  73         return reloc_get16(p) | (p[2] << 16);
  74 }
  75
  76 static uint32_t reloc_get32(uint8_t *p)
  77 {
  78         return reloc_get16(p) | (reloc_get16(p+2) << 16);
  79 }
  80
  81 static void reloc_put16(uint8_t *p, uint32_t val)
  82 {
  83         p[0] = val & 0xff;
  84         p[1] = (val >> 8) & 0xff;
  85 }
  86
  87 static void reloc_put24(uint8_t *p, uint32_t val)
  88 {
  89         reloc_put16(p, val);
  90         p[2] = (val >> 16) & 0xff;
  91 }
  92
  93 static void reloc_put32(uint8_t *p, uint32_t val)
  94 {
  95         reloc_put16(p, val);
  96         reloc_put16(p+2, val >> 16);
  97 }
  98
  99 /*
 100  * apply a REL relocation
 101  */
 102 int apply_relocate(Elf32_Shdr *sechdrs,
 103                    const char *strtab,
 104                    unsigned int symindex,
 105                    unsigned int relsec,
 106                    struct module *me)
 107 {
 108         printk(KERN_ERR "module %s: RELOCATION unsupported\n",
 109                me->name);
 110         return -ENOEXEC;
 111 }
 112
 113 /*
 114  * apply a RELA relocation
 115  */
 116 int apply_relocate_add(Elf32_Shdr *sechdrs,
 117                        const char *strtab,
 118                        unsigned int symindex,
 119                        unsigned int relsec,
 120                        struct module *me)
 121 {
 122         unsigned int i;
 123         Elf32_Rela *rel = (void *)sechdrs[relsec].sh_addr;
 124         Elf32_Sym *sym;
 125         Elf32_Addr relocation;
 126         uint8_t *location;
 127         uint32_t value;
 128
 129         DEBUGP("Applying relocate section %u to %u\n",
 130                relsec, sechdrs[relsec].sh_info);
 131
 132         for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rel); i++) {
 133                 /* this is where to make the change */
 134                 location = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr
 135                         + rel[i].r_offset;
 136
 137                 /* this is the symbol the relocation is referring to (note that
 138                  * all undefined symbols have been resolved by the caller) */
 139                 sym = (Elf32_Sym *)sechdrs[symindex].sh_addr
 140                         + ELF32_R_SYM(rel[i].r_info);
 141
 142                 /* this is the adjustment to be made */
 143                 relocation = sym->st_value + rel[i].r_addend;
 144
 145                 switch (ELF32_R_TYPE(rel[i].r_info)) {
 146                         /* for the first four relocation types, we add the
 147                          * adjustment into the value at the location given */
 148                 case R_MN10300_32:
 149                         value = reloc_get32(location);
 150                         value += relocation;
 151                         reloc_put32(location, value);
 152                         break;
 153                 case R_MN10300_24:
 154                         value = reloc_get24(location);
 155                         value += relocation;
 156                         reloc_put24(location, value);
 157                         break;
 158                 case R_MN10300_16:
 159                         value = reloc_get16(location);
 160                         value += relocation;
 161                         reloc_put16(location, value);
 162                         break;
 163                 case R_MN10300_8:
 164                         *location += relocation;
 165                         break;
 166
 167                         /* for the next three relocation types, we write the
 168                          * adjustment with the address subtracted over the
 169                          * value at the location given */
 170                 case R_MN10300_PCREL32:
 171                         value = relocation - (uint32_t) location;
 172                         reloc_put32(location, value);
 173                         break;
 174                 case R_MN10300_PCREL16:
 175                         value = relocation - (uint32_t) location;
 176                         reloc_put16(location, value);
 177                         break;
 178                 case R_MN10300_PCREL8:
 179                         *location = relocation - (uint32_t) location;
 180                         break;
 181
 182                 default:
 183                         printk(KERN_ERR "module %s: Unknown relocation: %u\n",
 184                                me->name, ELF32_R_TYPE(rel[i].r_info));
 185                         return -ENOEXEC;
 186                 }
 187         }
 188         return 0;
 189 }
 190
 191 /*
 192  * finish loading the module
 193  */
 194 int module_finalize(const Elf_Ehdr *hdr,
 195                     const Elf_Shdr *sechdrs,
 196                     struct module *me)
 197 {
 198         return 0;
 199 }
 200
 201 /*
 202  * finish clearing the module
 203  */
 204 void module_arch_cleanup(struct module *mod)
 205 {
 206 }