arch/sh/kernel/module.c

   1 /*  Kernel module help for SH.
   2
   3     SHcompact version by Kaz Kojima and Paul Mundt.
   4
   5     SHmedia bits:
   6
   7         Copyright 2004 SuperH (UK) Ltd
   8         Author: Richard Curnow
   9
  10         Based on the sh version, and on code from the sh64-specific parts of
  11         modutils, originally written by Richard Curnow and Ben Gaster.
  12
  13     This program is free software; you can redistribute it and/or modify
  14     it under the terms of the GNU General Public License as published by
  15     the Free Software Foundation; either version 2 of the License, or
  16     (at your option) any later version.
  17
  18     This program is distributed in the hope that it will be useful,
  19     but WITHOUT ANY WARRANTY; without even the implied warranty of
  20     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  21     GNU General Public License for more details.
  22
  23     You should have received a copy of the GNU General Public License
  24     along with this program; if not, write to the Free Software
  25     Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  26 */
  27 #include <linux/moduleloader.h>
  28 #include <linux/elf.h>
  29 #include <linux/vmalloc.h>
  30 #include <linux/fs.h>
  31 #include <linux/string.h>
  32 #include <linux/kernel.h>
  33
  34 void *module_alloc(unsigned long size)
  35 {
  36         if (size == 0)
  37                 return NULL;
  38         return vmalloc(size);
  39 }
  40
  41
  42 /* Free memory returned from module_alloc */
  43 void module_free(struct module *mod, void *module_region)
  44 {
  45         vfree(module_region);
  46         /* FIXME: If module_region == mod->init_region, trim exception
  47            table entries. */
  48 }
  49
  50 /* We don't need anything special. */
  51 int module_frob_arch_sections(Elf_Ehdr *hdr,
  52                               Elf_Shdr *sechdrs,
  53                               char *secstrings,
  54                               struct module *mod)
  55 {
  56         return 0;
  57 }
  58
  59 #ifdef CONFIG_SUPERH32
  60 #define COPY_UNALIGNED_WORD(sw, tw, align) \
  61 { \
  62         void *__s = &(sw), *__t = &(tw); \
  63         unsigned short *__s2 = __s, *__t2 = __t; \
  64         unsigned char *__s1 = __s, *__t1 = __t; \
  65         switch ((align)) \
  66         { \
  67         case 0: \
  68                 *(unsigned long *) __t = *(unsigned long *) __s; \
  69                 break; \
  70         case 2: \
  71                 *__t2++ = *__s2++; \
  72                 *__t2 = *__s2; \
  73                 break; \
  74         default: \
  75                 *__t1++ = *__s1++; \
  76                 *__t1++ = *__s1++; \
  77                 *__t1++ = *__s1++; \
  78                 *__t1 = *__s1; \
  79                 break; \
  80         } \
  81 }
  82 #else
  83 /* One thing SHmedia doesn't screw up! */
  84 #define COPY_UNALIGNED_WORD(sw, tw, align)      { (tw) = (sw); }
  85 #endif
  86
  87 int apply_relocate_add(Elf32_Shdr *sechdrs,
  88                    const char *strtab,
  89                    unsigned int symindex,
  90                    unsigned int relsec,
  91                    struct module *me)
  92 {
  93         unsigned int i;
  94         Elf32_Rela *rel = (void *)sechdrs[relsec].sh_addr;
  95         Elf32_Sym *sym;
  96         Elf32_Addr relocation;
  97         uint32_t *location;
  98         uint32_t value;
  99         int align;
 100
 101         pr_debug("Applying relocate section %u to %u\n", relsec,
 102                  sechdrs[relsec].sh_info);
 103         for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rel); i++) {
 104                 /* This is where to make the change */
 105                 location = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr
 106                         + rel[i].r_offset;
 107                 /* This is the symbol it is referring to.  Note that all
 108                    undefined symbols have been resolved.  */
 109                 sym = (Elf32_Sym *)sechdrs[symindex].sh_addr
 110                         + ELF32_R_SYM(rel[i].r_info);
 111                 relocation = sym->st_value + rel[i].r_addend;
 112                 align = (int)location & 3;
 113
 114 #ifdef CONFIG_SUPERH64
 115                 /* For text addresses, bit2 of the st_other field indicates
 116                  * whether the symbol is SHmedia (1) or SHcompact (0).  If
 117                  * SHmedia, the LSB of the symbol needs to be asserted
 118                  * for the CPU to be in SHmedia mode when it starts executing
 119                  * the branch target. */
 120                 relocation |= (sym->st_other & 4);
 121 #endif
 122
 123                 switch (ELF32_R_TYPE(rel[i].r_info)) {
 124                 case R_SH_DIR32:
 125                         COPY_UNALIGNED_WORD (*location, value, align);
 126                         value += relocation;
 127                         COPY_UNALIGNED_WORD (value, *location, align);
 128                         break;
 129                 case R_SH_REL32:
 130                         relocation = (relocation - (Elf32_Addr) location);
 131                         COPY_UNALIGNED_WORD (*location, value, align);
 132                         value += relocation;
 133                         COPY_UNALIGNED_WORD (value, *location, align);
 134                         break;
 135                 case R_SH_IMM_LOW16:
 136                         *location = (*location & ~0x3fffc00) |
 137                                 ((relocation & 0xffff) << 10);
 138                         break;
 139                 case R_SH_IMM_MEDLOW16:
 140                         *location = (*location & ~0x3fffc00) |
 141                                 (((relocation >> 16) & 0xffff) << 10);
 142                         break;
 143                 case R_SH_IMM_LOW16_PCREL:
 144                         relocation -= (Elf32_Addr) location;
 145                         *location = (*location & ~0x3fffc00) |
 146                                 ((relocation & 0xffff) << 10);
 147                         break;
 148                 case R_SH_IMM_MEDLOW16_PCREL:
 149                         relocation -= (Elf32_Addr) location;
 150                         *location = (*location & ~0x3fffc00) |
 151                                 (((relocation >> 16) & 0xffff) << 10);
 152                         break;
 153                 default:
 154                         printk(KERN_ERR "module %s: Unknown relocation: %u\n",
 155                                me->name, ELF32_R_TYPE(rel[i].r_info));
 156                         return -ENOEXEC;
 157                 }
 158         }
 159         return 0;
 160 }
 161
 162 int apply_relocate(Elf32_Shdr *sechdrs,
 163                        const char *strtab,
 164                        unsigned int symindex,
 165                        unsigned int relsec,
 166                        struct module *me)
 167 {
 168         printk(KERN_ERR "module %s: REL RELOCATION unsupported\n",
 169                me->name);
 170         return -ENOEXEC;
 171 }
 172
 173 int module_finalize(const Elf_Ehdr *hdr,
 174                     const Elf_Shdr *sechdrs,
 175                     struct module *me)
 176 {
 177         return 0;
 178 }
 179
 180 void module_arch_cleanup(struct module *mod)
 181 {
 182 }