arch/openrisc/kernel/module.c

   1 /*
   2  * OpenRISC module.c
   3  *
   4  * Linux architectural port borrowing liberally from similar works of
   5  * others.  All original copyrights apply as per the original source
   6  * declaration.
   7  *
   8  * Modifications for the OpenRISC architecture:
   9  * Copyright (C) 2010-2011 Jonas Bonn <jonas@southpole.se>
  10  *
  11  *      This program is free software; you can redistribute it and/or
  12  *      modify it under the terms of the GNU General Public License
  13  *      as published by the Free Software Foundation; either version
  14  *      2 of the License, or (at your option) any later version.
  15  */
  16
  17 #include <linux/moduleloader.h>
  18 #include <linux/elf.h>
  19
  20 int apply_relocate_add(Elf32_Shdr *sechdrs,
  21                        const char *strtab,
  22                        unsigned int symindex,
  23                        unsigned int relsec,
  24                        struct module *me)
  25 {
  26         unsigned int i;
  27         Elf32_Rela *rel = (void *)sechdrs[relsec].sh_addr;
  28         Elf32_Sym *sym;
  29         uint32_t *location;
  30         uint32_t value;
  31
  32         pr_debug("Applying relocate section %u to %u\n", relsec,
  33                  sechdrs[relsec].sh_info);
  34         for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rel); i++) {
  35                 /* This is where to make the change */
  36                 location = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr
  37                         + rel[i].r_offset;
  38
  39                 /* This is the symbol it is referring to.  Note that all
  40                    undefined symbols have been resolved.  */
  41                 sym = (Elf32_Sym *)sechdrs[symindex].sh_addr
  42                         + ELF32_R_SYM(rel[i].r_info);
  43                 value = sym->st_value + rel[i].r_addend;
  44
  45                 switch (ELF32_R_TYPE(rel[i].r_info)) {
  46                 case R_OR32_32:
  47                         *location = value;
  48                         break;
  49                 case R_OR32_CONST:
  50                         location = (uint16_t *)location + 1;
  51                         *((uint16_t *)location) = (uint16_t) (value);
  52                         break;
  53                 case R_OR32_CONSTH:
  54                         location = (uint16_t *)location + 1;
  55                         *((uint16_t *)location) = (uint16_t) (value >> 16);
  56                         break;
  57                 case R_OR32_JUMPTARG:
  58                         value -= (uint32_t)location;
  59                         value >>= 2;
  60                         value &= 0x03ffffff;
  61                         value |= *location & 0xfc000000;
  62                         *location = value;
  63                         break;
  64                 default:
  65                         pr_err("module %s: Unknown relocation: %u\n",
  66                                me->name, ELF32_R_TYPE(rel[i].r_info));
  67                         break;
  68                 }
  69         }
  70
  71         return 0;
  72 }