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/bug.h>
  31 #include <linux/fs.h>
  32 #include <linux/string.h>
  33 #include <linux/kernel.h>
  34 #include <asm/unaligned.h>
  35
  36 void *module_alloc(unsigned long size)
  37 {
  38         if (size == 0)
  39                 return NULL;
  40
  41         return vmalloc_exec(size);
  42 }
  43
  44
  45 /* Free memory returned from module_alloc */
  46 void module_free(struct module *mod, void *module_region)
  47 {
  48         vfree(module_region);
  49         /* FIXME: If module_region == mod->init_region, trim exception
  50            table entries. */
  51 }
  52
  53 /* We don't need anything special. */
  54 int module_frob_arch_sections(Elf_Ehdr *hdr,
  55                               Elf_Shdr *sechdrs,
  56                               char *secstrings,
  57                               struct module *mod)
  58 {
  59         return 0;
  60 }
  61
  62 int apply_relocate_add(Elf32_Shdr *sechdrs,
  63                    const char *strtab,
  64                    unsigned int symindex,
  65                    unsigned int relsec,
  66                    struct module *me)
  67 {
  68         unsigned int i;
  69         Elf32_Rela *rel = (void *)sechdrs[relsec].sh_addr;
  70         Elf32_Sym *sym;
  71         Elf32_Addr relocation;
  72         uint32_t *location;
  73         uint32_t value;
  74
  75         pr_debug("Applying relocate section %u to %u\n", relsec,
  76                  sechdrs[relsec].sh_info);
  77         for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rel); i++) {
  78                 /* This is where to make the change */
  79                 location = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr
  80                         + rel[i].r_offset;
  81                 /* This is the symbol it is referring to.  Note that all
  82                    undefined symbols have been resolved.  */
  83                 sym = (Elf32_Sym *)sechdrs[symindex].sh_addr
  84                         + ELF32_R_SYM(rel[i].r_info);
  85                 relocation = sym->st_value + rel[i].r_addend;
  86
  87 #ifdef CONFIG_SUPERH64
  88                 /* For text addresses, bit2 of the st_other field indicates
  89                  * whether the symbol is SHmedia (1) or SHcompact (0).  If
  90                  * SHmedia, the LSB of the symbol needs to be asserted
  91                  * for the CPU to be in SHmedia mode when it starts executing
  92                  * the branch target. */
  93                 relocation |= (sym->st_other & 4);
  94 #endif
  95
  96                 switch (ELF32_R_TYPE(rel[i].r_info)) {
  97                 case R_SH_DIR32:
  98                         value = get_unaligned(location);
  99                         value += relocation;
 100                         put_unaligned(value, location);
 101                         break;
 102                 case R_SH_REL32:
 103                         relocation = (relocation - (Elf32_Addr) location);
 104                         value = get_unaligned(location);
 105                         value += relocation;
 106                         put_unaligned(value, location);
 107                         break;
 108                 case R_SH_IMM_LOW16:
 109                         *location = (*location & ~0x3fffc00) |
 110                                 ((relocation & 0xffff) << 10);
 111                         break;
 112                 case R_SH_IMM_MEDLOW16:
 113                         *location = (*location & ~0x3fffc00) |
 114                                 (((relocation >> 16) & 0xffff) << 10);
 115                         break;
 116                 case R_SH_IMM_LOW16_PCREL:
 117                         relocation -= (Elf32_Addr) location;
 118                         *location = (*location & ~0x3fffc00) |
 119                                 ((relocation & 0xffff) << 10);
 120                         break;
 121                 case R_SH_IMM_MEDLOW16_PCREL:
 122                         relocation -= (Elf32_Addr) location;
 123                         *location = (*location & ~0x3fffc00) |
 124                                 (((relocation >> 16) & 0xffff) << 10);
 125                         break;
 126                 default:
 127                         printk(KERN_ERR "module %s: Unknown relocation: %u\n",
 128                                me->name, ELF32_R_TYPE(rel[i].r_info));
 129                         return -ENOEXEC;
 130                 }
 131         }
 132         return 0;
 133 }
 134
 135 int apply_relocate(Elf32_Shdr *sechdrs,
 136                        const char *strtab,
 137                        unsigned int symindex,
 138                        unsigned int relsec,
 139                        struct module *me)
 140 {
 141         printk(KERN_ERR "module %s: REL RELOCATION unsupported\n",
 142                me->name);
 143         return -ENOEXEC;
 144 }
 145
 146 int module_finalize(const Elf_Ehdr *hdr,
 147                     const Elf_Shdr *sechdrs,
 148                     struct module *me)
 149 {
 150         return module_bug_finalize(hdr, sechdrs, me);
 151 }
 152
 153 void module_arch_cleanup(struct module *mod)
 154 {
 155         module_bug_cleanup(mod);
 156 }