arch/sh/kernel/module.c

   1 /*  Kernel module help for SH.
   2
   3     This program is free software; you can redistribute it and/or modify
   4     it under the terms of the GNU General Public License as published by
   5     the Free Software Foundation; either version 2 of the License, or
   6     (at your option) any later version.
   7
   8     This program is distributed in the hope that it will be useful,
   9     but WITHOUT ANY WARRANTY; without even the implied warranty of
  10     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  11     GNU General Public License for more details.
  12
  13     You should have received a copy of the GNU General Public License
  14     along with this program; if not, write to the Free Software
  15     Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  16 */
  17 #include <linux/moduleloader.h>
  18 #include <linux/elf.h>
  19 #include <linux/vmalloc.h>
  20 #include <linux/fs.h>
  21 #include <linux/string.h>
  22 #include <linux/kernel.h>
  23
  24 #if 0
  25 #define DEBUGP printk
  26 #else
  27 #define DEBUGP(fmt...)
  28 #endif
  29
  30 void *module_alloc(unsigned long size)
  31 {
  32         if (size == 0)
  33                 return NULL;
  34         return vmalloc(size);
  35 }
  36
  37
  38 /* Free memory returned from module_alloc */
  39 void module_free(struct module *mod, void *module_region)
  40 {
  41         vfree(module_region);
  42         /* FIXME: If module_region == mod->init_region, trim exception
  43            table entries. */
  44 }
  45
  46 /* We don't need anything special. */
  47 int module_frob_arch_sections(Elf_Ehdr *hdr,
  48                               Elf_Shdr *sechdrs,
  49                               char *secstrings,
  50                               struct module *mod)
  51 {
  52         return 0;
  53 }
  54
  55 #define COPY_UNALIGNED_WORD(sw, tw, align) \
  56 { \
  57         void *__s = &(sw), *__t = &(tw); \
  58         switch ((align)) \
  59         { \
  60         case 0: \
  61                 *(unsigned long *) __t = *(unsigned long *) __s; \
  62                 break; \
  63         case 2: \
  64                 *((unsigned short *) __t)++ = *((unsigned short *) __s)++; \
  65                 *((unsigned short *) __t) = *((unsigned short *) __s); \
  66                 break; \
  67         default: \
  68                 *((unsigned char *) __t)++ = *((unsigned char *) __s)++; \
  69                 *((unsigned char *) __t)++ = *((unsigned char *) __s)++; \
  70                 *((unsigned char *) __t)++ = *((unsigned char *) __s)++; \
  71                 *((unsigned char *) __t) = *((unsigned char *) __s); \
  72                 break; \
  73         } \
  74 }
  75
  76 int apply_relocate_add(Elf32_Shdr *sechdrs,
  77                    const char *strtab,
  78                    unsigned int symindex,
  79                    unsigned int relsec,
  80                    struct module *me)
  81 {
  82         unsigned int i;
  83         Elf32_Rela *rel = (void *)sechdrs[relsec].sh_addr;
  84         Elf32_Sym *sym;
  85         Elf32_Addr relocation;
  86         uint32_t *location;
  87         uint32_t value;
  88         int align;
  89
  90         DEBUGP("Applying relocate section %u to %u\n", relsec,
  91                sechdrs[relsec].sh_info);
  92         for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rel); i++) {
  93                 /* This is where to make the change */
  94                 location = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr
  95                         + rel[i].r_offset;
  96                 /* This is the symbol it is referring to.  Note that all
  97                    undefined symbols have been resolved.  */
  98                 sym = (Elf32_Sym *)sechdrs[symindex].sh_addr
  99                         + ELF32_R_SYM(rel[i].r_info);
 100                 relocation = sym->st_value + rel[i].r_addend;
 101                 align = (int)location & 3;
 102
 103                 switch (ELF32_R_TYPE(rel[i].r_info)) {
 104                 case R_SH_DIR32:
 105                         COPY_UNALIGNED_WORD (*location, value, align);
 106                         value += relocation;
 107                         COPY_UNALIGNED_WORD (value, *location, align);
 108                         break;
 109                 case R_SH_REL32:
 110                         relocation = (relocation - (Elf32_Addr) location);
 111                         COPY_UNALIGNED_WORD (*location, value, align);
 112                         value += relocation;
 113                         COPY_UNALIGNED_WORD (value, *location, align);
 114                         break;
 115                 default:
 116                         printk(KERN_ERR "module %s: Unknown relocation: %u\n",
 117                                me->name, ELF32_R_TYPE(rel[i].r_info));
 118                         return -ENOEXEC;
 119                 }
 120         }
 121         return 0;
 122 }
 123
 124 int apply_relocate(Elf32_Shdr *sechdrs,
 125                        const char *strtab,
 126                        unsigned int symindex,
 127                        unsigned int relsec,
 128                        struct module *me)
 129 {
 130         printk(KERN_ERR "module %s: REL RELOCATION unsupported\n",
 131                me->name);
 132         return -ENOEXEC;
 133 }
 134
 135 int module_finalize(const Elf_Ehdr *hdr,
 136                     const Elf_Shdr *sechdrs,
 137                     struct module *me)
 138 {
 139         return 0;
 140 }