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 #include <asm/dwarf.h>
  36
  37 void *module_alloc(unsigned long size)
  38 {
  39         if (size == 0)
  40                 return NULL;
  41
  42         return vmalloc_exec(size);
  43 }
  44
  45
  46 /* Free memory returned from module_alloc */
  47 void module_free(struct module *mod, void *module_region)
  48 {
  49         vfree(module_region);
  50 }
  51
  52 /* We don't need anything special. */
  53 int module_frob_arch_sections(Elf_Ehdr *hdr,
  54                               Elf_Shdr *sechdrs,
  55                               char *secstrings,
  56                               struct module *mod)
  57 {
  58         return 0;
  59 }
  60
  61 int apply_relocate_add(Elf32_Shdr *sechdrs,
  62                    const char *strtab,
  63                    unsigned int symindex,
  64                    unsigned int relsec,
  65                    struct module *me)
  66 {
  67         unsigned int i;
  68         Elf32_Rela *rel = (void *)sechdrs[relsec].sh_addr;
  69         Elf32_Sym *sym;
  70         Elf32_Addr relocation;
  71         uint32_t *location;
  72         uint32_t value;
  73
  74         pr_debug("Applying relocate section %u to %u\n", relsec,
  75                  sechdrs[relsec].sh_info);
  76         for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rel); i++) {
  77                 /* This is where to make the change */
  78                 location = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr
  79                         + rel[i].r_offset;
  80                 /* This is the symbol it is referring to.  Note that all
  81                    undefined symbols have been resolved.  */
  82                 sym = (Elf32_Sym *)sechdrs[symindex].sh_addr
  83                         + ELF32_R_SYM(rel[i].r_info);
  84                 relocation = sym->st_value + rel[i].r_addend;
  85
  86 #ifdef CONFIG_SUPERH64
  87                 /* For text addresses, bit2 of the st_other field indicates
  88                  * whether the symbol is SHmedia (1) or SHcompact (0).  If
  89                  * SHmedia, the LSB of the symbol needs to be asserted
  90                  * for the CPU to be in SHmedia mode when it starts executing
  91                  * the branch target. */
  92                 relocation |= !!(sym->st_other & 4);
  93 #endif
  94
  95                 switch (ELF32_R_TYPE(rel[i].r_info)) {
  96                 case R_SH_NONE:
  97                         break;
  98                 case R_SH_DIR32:
  99                         value = get_unaligned(location);
 100                         value += relocation;
 101                         put_unaligned(value, location);
 102                         break;
 103                 case R_SH_REL32:
 104                         relocation = (relocation - (Elf32_Addr) location);
 105                         value = get_unaligned(location);
 106                         value += relocation;
 107                         put_unaligned(value, location);
 108                         break;
 109                 case R_SH_IMM_LOW16:
 110                         *location = (*location & ~0x3fffc00) |
 111                                 ((relocation & 0xffff) << 10);
 112                         break;
 113                 case R_SH_IMM_MEDLOW16:
 114                         *location = (*location & ~0x3fffc00) |
 115                                 (((relocation >> 16) & 0xffff) << 10);
 116                         break;
 117                 case R_SH_IMM_LOW16_PCREL:
 118                         relocation -= (Elf32_Addr) location;
 119                         *location = (*location & ~0x3fffc00) |
 120                                 ((relocation & 0xffff) << 10);
 121                         break;
 122                 case R_SH_IMM_MEDLOW16_PCREL:
 123                         relocation -= (Elf32_Addr) location;
 124                         *location = (*location & ~0x3fffc00) |
 125                                 (((relocation >> 16) & 0xffff) << 10);
 126                         break;
 127                 default:
 128                         printk(KERN_ERR "module %s: Unknown relocation: %u\n",
 129                                me->name, ELF32_R_TYPE(rel[i].r_info));
 130                         return -ENOEXEC;
 131                 }
 132         }
 133         return 0;
 134 }
 135
 136 int apply_relocate(Elf32_Shdr *sechdrs,
 137                        const char *strtab,
 138                        unsigned int symindex,
 139                        unsigned int relsec,
 140                        struct module *me)
 141 {
 142         printk(KERN_ERR "module %s: REL RELOCATION unsupported\n",
 143                me->name);
 144         return -ENOEXEC;
 145 }
 146
 147 int module_finalize(const Elf_Ehdr *hdr,
 148                     const Elf_Shdr *sechdrs,
 149                     struct module *me)
 150 {
 151         int ret = 0;
 152
 153         ret |= module_dwarf_finalize(hdr, sechdrs, me);
 154
 155         return ret;
 156 }
 157
 158 void module_arch_cleanup(struct module *mod)
 159 {
 160         module_dwarf_cleanup(mod);
 161 }