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