LXR linux/arch/mips/kernel/module-rela.c

   1/*
   2 *  This program is free software; you can redistribute it and/or modify
   3 *  it under the terms of the GNU General Public License as published by
   4 *  the Free Software Foundation; either version 2 of the License, or
   5 *  (at your option) any later version.
   6 *
   7 *  This program is distributed in the hope that it will be useful,
   8 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
   9 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  10 *  GNU General Public License for more details.
  11 *
  12 *  You should have received a copy of the GNU General Public License
  13 *  along with this program; if not, write to the Free Software
  14 *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  15 *
  16 *  Copyright (C) 2001 Rusty Russell.
  17 *  Copyright (C) 2003, 2004 Ralf Baechle (ralf@linux-mips.org)
  18 *  Copyright (C) 2005 Thiemo Seufer
  19 */
  20
  21#include <linux/elf.h>
  22#include <linux/err.h>
  23#include <linux/errno.h>
  24#include <linux/moduleloader.h>
  25
  26extern int apply_r_mips_none(struct module *me, u32 *location, Elf_Addr v);
  27
  28static int apply_r_mips_32_rela(struct module *me, u32 *location, Elf_Addr v)
  29{
  30        *location = v;
  31
  32        return 0;
  33}
  34
  35static int apply_r_mips_26_rela(struct module *me, u32 *location, Elf_Addr v)
  36{
  37        if (v % 4) {
  38                pr_err("module %s: dangerous R_MIPS_26 RELArelocation\n",
  39                       me->name);
  40                return -ENOEXEC;
  41        }
  42
  43        if ((v & 0xf0000000) != (((unsigned long)location + 4) & 0xf0000000)) {
  44                printk(KERN_ERR
  45                       "module %s: relocation overflow\n",
  46                       me->name);
  47                return -ENOEXEC;
  48        }
  49
  50        *location = (*location & ~0x03ffffff) | ((v >> 2) & 0x03ffffff);
  51
  52        return 0;
  53}
  54
  55static int apply_r_mips_hi16_rela(struct module *me, u32 *location, Elf_Addr v)
  56{
  57        *location = (*location & 0xffff0000) |
  58                    ((((long long) v + 0x8000LL) >> 16) & 0xffff);
  59
  60        return 0;
  61}
  62
  63static int apply_r_mips_lo16_rela(struct module *me, u32 *location, Elf_Addr v)
  64{
  65        *location = (*location & 0xffff0000) | (v & 0xffff);
  66
  67        return 0;
  68}
  69
  70static int apply_r_mips_64_rela(struct module *me, u32 *location, Elf_Addr v)
  71{
  72        *(Elf_Addr *)location = v;
  73
  74        return 0;
  75}
  76
  77static int apply_r_mips_higher_rela(struct module *me, u32 *location,
  78                                    Elf_Addr v)
  79{
  80        *location = (*location & 0xffff0000) |
  81                    ((((long long) v + 0x80008000LL) >> 32) & 0xffff);
  82
  83        return 0;
  84}
  85
  86static int apply_r_mips_highest_rela(struct module *me, u32 *location,
  87                                     Elf_Addr v)
  88{
  89        *location = (*location & 0xffff0000) |
  90                    ((((long long) v + 0x800080008000LL) >> 48) & 0xffff);
  91
  92        return 0;
  93}
  94
  95static int (*reloc_handlers_rela[]) (struct module *me, u32 *location,
  96                                Elf_Addr v) = {
  97        [R_MIPS_NONE]           = apply_r_mips_none,
  98        [R_MIPS_32]             = apply_r_mips_32_rela,
  99        [R_MIPS_26]             = apply_r_mips_26_rela,
 100        [R_MIPS_HI16]           = apply_r_mips_hi16_rela,
 101        [R_MIPS_LO16]           = apply_r_mips_lo16_rela,
 102        [R_MIPS_64]             = apply_r_mips_64_rela,
 103        [R_MIPS_HIGHER]         = apply_r_mips_higher_rela,
 104        [R_MIPS_HIGHEST]        = apply_r_mips_highest_rela
 105};
 106
 107int apply_relocate_add(Elf_Shdr *sechdrs, const char *strtab,
 108                       unsigned int symindex, unsigned int relsec,
 109                       struct module *me)
 110{
 111        Elf_Mips_Rela *rel = (void *) sechdrs[relsec].sh_addr;
 112        Elf_Sym *sym;
 113        u32 *location;
 114        unsigned int i;
 115        Elf_Addr v;
 116        int res;
 117
 118        pr_debug("Applying relocate section %u to %u\n", relsec,
 119               sechdrs[relsec].sh_info);
 120
 121        for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rel); i++) {
 122                /* This is where to make the change */
 123                location = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr
 124                        + rel[i].r_offset;
 125                /* This is the symbol it is referring to */
 126                sym = (Elf_Sym *)sechdrs[symindex].sh_addr
 127                        + ELF_MIPS_R_SYM(rel[i]);
 128                if (IS_ERR_VALUE(sym->st_value)) {
 129                        /* Ignore unresolved weak symbol */
 130                        if (ELF_ST_BIND(sym->st_info) == STB_WEAK)
 131                                continue;
 132                        printk(KERN_WARNING "%s: Unknown symbol %s\n",
 133                               me->name, strtab + sym->st_name);
 134                        return -ENOENT;
 135                }
 136
 137                v = sym->st_value + rel[i].r_addend;
 138
 139                res = reloc_handlers_rela[ELF_MIPS_R_TYPE(rel[i])](me, location, v);
 140                if (res)
 141                        return res;
 142        }
 143
 144        return 0;
 145}
 146