release/src-rt-6.x.4708/linux/linux-2.6.36/arch/x86/kernel/module.c

   1 /*  Kernel module help for x86.
   2     Copyright (C) 2001 Rusty Russell.
   3
   4     This program is free software; you can redistribute it and/or modify
   5     it under the terms of the GNU General Public License as published by
   6     the Free Software Foundation; either version 2 of the License, or
   7     (at your option) any later version.
   8
   9     This program is distributed in the hope that it will be useful,
  10     but WITHOUT ANY WARRANTY; without even the implied warranty of
  11     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12     GNU General Public License for more details.
  13
  14     You should have received a copy of the GNU General Public License
  15     along with this program; if not, write to the Free Software
  16     Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  17 */
  18 #include <linux/moduleloader.h>
  19 #include <linux/elf.h>
  20 #include <linux/vmalloc.h>
  21 #include <linux/fs.h>
  22 #include <linux/string.h>
  23 #include <linux/kernel.h>
  24 #include <linux/bug.h>
  25 #include <linux/mm.h>
  26 #include <linux/gfp.h>
  27
  28 #include <asm/system.h>
  29 #include <asm/page.h>
  30 #include <asm/pgtable.h>
  31
  32 #define DEBUGP(fmt...)
  33
  34 void *module_alloc(unsigned long size)
  35 {
  36         struct vm_struct *area;
  37
  38         if (!size)
  39                 return NULL;
  40         size = PAGE_ALIGN(size);
  41         if (size > MODULES_LEN)
  42                 return NULL;
  43
  44         area = __get_vm_area(size, VM_ALLOC, MODULES_VADDR, MODULES_END);
  45         if (!area)
  46                 return NULL;
  47
  48         return __vmalloc_area(area, GFP_KERNEL | __GFP_HIGHMEM,
  49                                         PAGE_KERNEL_EXEC);
  50 }
  51
  52 /* Free memory returned from module_alloc */
  53 void module_free(struct module *mod, void *module_region)
  54 {
  55         vfree(module_region);
  56 }
  57
  58 /* We don't need anything special. */
  59 int module_frob_arch_sections(Elf_Ehdr *hdr,
  60                               Elf_Shdr *sechdrs,
  61                               char *secstrings,
  62                               struct module *mod)
  63 {
  64         return 0;
  65 }
  66
  67 #ifdef CONFIG_X86_32
  68 int apply_relocate(Elf32_Shdr *sechdrs,
  69                    const char *strtab,
  70                    unsigned int symindex,
  71                    unsigned int relsec,
  72                    struct module *me)
  73 {
  74         unsigned int i;
  75         Elf32_Rel *rel = (void *)sechdrs[relsec].sh_addr;
  76         Elf32_Sym *sym;
  77         uint32_t *location;
  78
  79         DEBUGP("Applying relocate section %u to %u\n", relsec,
  80                sechdrs[relsec].sh_info);
  81         for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rel); i++) {
  82                 /* This is where to make the change */
  83                 location = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr
  84                         + rel[i].r_offset;
  85                 /* This is the symbol it is referring to.  Note that all
  86                    undefined symbols have been resolved.  */
  87                 sym = (Elf32_Sym *)sechdrs[symindex].sh_addr
  88                         + ELF32_R_SYM(rel[i].r_info);
  89
  90                 switch (ELF32_R_TYPE(rel[i].r_info)) {
  91                 case R_386_32:
  92                         /* We add the value into the location given */
  93                         *location += sym->st_value;
  94                         break;
  95                 case R_386_PC32:
  96                         /* Add the value, subtract its postition */
  97                         *location += sym->st_value - (uint32_t)location;
  98                         break;
  99                 default:
 100                         printk(KERN_ERR "module %s: Unknown relocation: %u\n",
 101                                me->name, ELF32_R_TYPE(rel[i].r_info));
 102                         return -ENOEXEC;
 103                 }
 104         }
 105         return 0;
 106 }
 107
 108 int apply_relocate_add(Elf32_Shdr *sechdrs,
 109                        const char *strtab,
 110                        unsigned int symindex,
 111                        unsigned int relsec,
 112                        struct module *me)
 113 {
 114         printk(KERN_ERR "module %s: ADD RELOCATION unsupported\n",
 115                me->name);
 116         return -ENOEXEC;
 117 }
 118 #else /*X86_64*/
 119 int apply_relocate_add(Elf64_Shdr *sechdrs,
 120                    const char *strtab,
 121                    unsigned int symindex,
 122                    unsigned int relsec,
 123                    struct module *me)
 124 {
 125         unsigned int i;
 126         Elf64_Rela *rel = (void *)sechdrs[relsec].sh_addr;
 127         Elf64_Sym *sym;
 128         void *loc;
 129         u64 val;
 130
 131         DEBUGP("Applying relocate section %u to %u\n", relsec,
 132                sechdrs[relsec].sh_info);
 133         for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rel); i++) {
 134                 /* This is where to make the change */
 135                 loc = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr
 136                         + rel[i].r_offset;
 137
 138                 /* This is the symbol it is referring to.  Note that all
 139                    undefined symbols have been resolved.  */
 140                 sym = (Elf64_Sym *)sechdrs[symindex].sh_addr
 141                         + ELF64_R_SYM(rel[i].r_info);
 142
 143                 DEBUGP("type %d st_value %Lx r_addend %Lx loc %Lx\n",
 144                         (int)ELF64_R_TYPE(rel[i].r_info),
 145                         sym->st_value, rel[i].r_addend, (u64)loc);
 146
 147                 val = sym->st_value + rel[i].r_addend;
 148
 149                 switch (ELF64_R_TYPE(rel[i].r_info)) {
 150                 case R_X86_64_NONE:
 151                         break;
 152                 case R_X86_64_64:
 153                         *(u64 *)loc = val;
 154                         break;
 155                 case R_X86_64_32:
 156                         *(u32 *)loc = val;
 157                         if (val != *(u32 *)loc)
 158                                 goto overflow;
 159                         break;
 160                 case R_X86_64_32S:
 161                         *(s32 *)loc = val;
 162                         if ((s64)val != *(s32 *)loc)
 163                                 goto overflow;
 164                         break;
 165                 case R_X86_64_PC32:
 166                         val -= (u64)loc;
 167                         *(u32 *)loc = val;
 168                         break;
 169                 default:
 170                         printk(KERN_ERR "module %s: Unknown rela relocation: %llu\n",
 171                                me->name, ELF64_R_TYPE(rel[i].r_info));
 172                         return -ENOEXEC;
 173                 }
 174         }
 175         return 0;
 176
 177 overflow:
 178         printk(KERN_ERR "overflow in relocation type %d val %Lx\n",
 179                (int)ELF64_R_TYPE(rel[i].r_info), val);
 180         printk(KERN_ERR "`%s' likely not compiled with -mcmodel=kernel\n",
 181                me->name);
 182         return -ENOEXEC;
 183 }
 184
 185 int apply_relocate(Elf_Shdr *sechdrs,
 186                    const char *strtab,
 187                    unsigned int symindex,
 188                    unsigned int relsec,
 189                    struct module *me)
 190 {
 191         printk(KERN_ERR "non add relocation not supported\n");
 192         return -ENOSYS;
 193 }
 194
 195 #endif
 196
 197 int module_finalize(const Elf_Ehdr *hdr,
 198                     const Elf_Shdr *sechdrs,
 199                     struct module *me)
 200 {
 201         const Elf_Shdr *s, *text = NULL, *alt = NULL, *locks = NULL,
 202                 *para = NULL;
 203         char *secstrings = (void *)hdr + sechdrs[hdr->e_shstrndx].sh_offset;
 204
 205         for (s = sechdrs; s < sechdrs + hdr->e_shnum; s++) {
 206                 if (!strcmp(".text", secstrings + s->sh_name))
 207                         text = s;
 208                 if (!strcmp(".altinstructions", secstrings + s->sh_name))
 209                         alt = s;
 210                 if (!strcmp(".smp_locks", secstrings + s->sh_name))
 211                         locks = s;
 212                 if (!strcmp(".parainstructions", secstrings + s->sh_name))
 213                         para = s;
 214         }
 215
 216         if (alt) {
 217                 /* patch .altinstructions */
 218                 void *aseg = (void *)alt->sh_addr;
 219                 apply_alternatives(aseg, aseg + alt->sh_size);
 220         }
 221         if (locks && text) {
 222                 void *lseg = (void *)locks->sh_addr;
 223                 void *tseg = (void *)text->sh_addr;
 224                 alternatives_smp_module_add(me, me->name,
 225                                             lseg, lseg + locks->sh_size,
 226                                             tseg, tseg + text->sh_size);
 227         }
 228
 229         if (para) {
 230                 void *pseg = (void *)para->sh_addr;
 231                 apply_paravirt(pseg, pseg + para->sh_size);
 232         }
 233
 234         return 0;
 235 }
 236
 237 void module_arch_cleanup(struct module *mod)
 238 {
 239         alternatives_smp_module_del(mod);
 240 }