arch/x86/kernel/module_64.c

   1 /*  Kernel module help for x86-64
   2     Copyright (C) 2001 Rusty Russell.
   3     Copyright (C) 2002,2003 Andi Kleen, SuSE Labs.
   4
   5     This program is free software; you can redistribute it and/or modify
   6     it under the terms of the GNU General Public License as published by
   7     the Free Software Foundation; either version 2 of the License, or
   8     (at your option) any later version.
   9
  10     This program is distributed in the hope that it will be useful,
  11     but WITHOUT ANY WARRANTY; without even the implied warranty of
  12     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13     GNU General Public License for more details.
  14
  15     You should have received a copy of the GNU General Public License
  16     along with this program; if not, write to the Free Software
  17     Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  18 */
  19 #include <linux/moduleloader.h>
  20 #include <linux/elf.h>
  21 #include <linux/vmalloc.h>
  22 #include <linux/fs.h>
  23 #include <linux/string.h>
  24 #include <linux/kernel.h>
  25 #include <linux/mm.h>
  26 #include <linux/slab.h>
  27 #include <linux/bug.h>
  28
  29 #include <asm/system.h>
  30 #include <asm/page.h>
  31 #include <asm/pgtable.h>
  32
  33 #define DEBUGP(fmt...)
  34
  35 #ifndef CONFIG_UML
  36 void *module_alloc(unsigned long size)
  37 {
  38         struct vm_struct *area;
  39
  40         if (!size)
  41                 return NULL;
  42         size = PAGE_ALIGN(size);
  43         if (size > MODULES_LEN)
  44                 return NULL;
  45
  46         area = __get_vm_area(size, VM_ALLOC, MODULES_VADDR, MODULES_END);
  47         if (!area)
  48                 return NULL;
  49
  50         return __vmalloc_area(area, GFP_KERNEL, PAGE_KERNEL_EXEC);
  51 }
  52 #endif
  53
  54 int apply_relocate_add(Elf64_Shdr *sechdrs,
  55                    const char *strtab,
  56                    unsigned int symindex,
  57                    unsigned int relsec,
  58                    struct module *me)
  59 {
  60         unsigned int i;
  61         Elf64_Rela *rel = (void *)sechdrs[relsec].sh_addr;
  62         Elf64_Sym *sym;
  63         void *loc;
  64         u64 val;
  65
  66         DEBUGP("Applying relocate section %u to %u\n", relsec,
  67                sechdrs[relsec].sh_info);
  68         for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rel); i++) {
  69                 /* This is where to make the change */
  70                 loc = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr
  71                         + rel[i].r_offset;
  72
  73                 /* This is the symbol it is referring to.  Note that all
  74                    undefined symbols have been resolved.  */
  75                 sym = (Elf64_Sym *)sechdrs[symindex].sh_addr
  76                         + ELF64_R_SYM(rel[i].r_info);
  77
  78                 DEBUGP("type %d st_value %Lx r_addend %Lx loc %Lx\n",
  79                         (int)ELF64_R_TYPE(rel[i].r_info),
  80                         sym->st_value, rel[i].r_addend, (u64)loc);
  81
  82                 val = sym->st_value + rel[i].r_addend;
  83
  84                 switch (ELF64_R_TYPE(rel[i].r_info)) {
  85                 case R_X86_64_NONE:
  86                         break;
  87                 case R_X86_64_64:
  88                         *(u64 *)loc = val;
  89                         break;
  90                 case R_X86_64_32:
  91                         *(u32 *)loc = val;
  92                         if (val != *(u32 *)loc)
  93                                 goto overflow;
  94                         break;
  95                 case R_X86_64_32S:
  96                         *(s32 *)loc = val;
  97                         if ((s64)val != *(s32 *)loc)
  98                                 goto overflow;
  99                         break;
 100                 case R_X86_64_PC32:
 101                         val -= (u64)loc;
 102                         *(u32 *)loc = val;
 103 #if 0
 104                         if ((s64)val != *(s32 *)loc)
 105                                 goto overflow;
 106 #endif
 107                         break;
 108                 default:
 109                         printk(KERN_ERR "module %s: Unknown rela relocation: %llu\n",
 110                                me->name, ELF64_R_TYPE(rel[i].r_info));
 111                         return -ENOEXEC;
 112                 }
 113         }
 114         return 0;
 115
 116 overflow:
 117         printk(KERN_ERR "overflow in relocation type %d val %Lx\n",
 118                (int)ELF64_R_TYPE(rel[i].r_info), val);
 119         printk(KERN_ERR "`%s' likely not compiled with -mcmodel=kernel\n",
 120                me->name);
 121         return -ENOEXEC;
 122 }
 123
 124 int apply_relocate(Elf_Shdr *sechdrs,
 125                    const char *strtab,
 126                    unsigned int symindex,
 127                    unsigned int relsec,
 128                    struct module *me)
 129 {
 130         printk(KERN_ERR "non add relocation not supported\n");
 131         return -ENOSYS;
 132 }
 133