LXR linux/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
  20int 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}
  73