arch/openrisc/kernel/module.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * OpenRISC module.c
   4  *
   5  * Linux architectural port borrowing liberally from similar works of
   6  * others.  All original copyrights apply as per the original source
   7  * declaration.
   8  *
   9  * Modifications for the OpenRISC architecture:
  10  * Copyright (C) 2010-2011 Jonas Bonn <jonas@southpole.se>
  11  */
  12
  13 #include <linux/moduleloader.h>
  14 #include <linux/elf.h>
  15
  16 int apply_relocate_add(Elf32_Shdr *sechdrs,
  17                        const char *strtab,
  18                        unsigned int symindex,
  19                        unsigned int relsec,
  20                        struct module *me)
  21 {
  22         unsigned int i;
  23         Elf32_Rela *rel = (void *)sechdrs[relsec].sh_addr;
  24         Elf32_Sym *sym;
  25         uint32_t *location;
  26         uint32_t value;
  27
  28         pr_debug("Applying relocate section %u to %u\n", relsec,
  29                  sechdrs[relsec].sh_info);
  30         for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rel); i++) {
  31                 /* This is where to make the change */
  32                 location = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr
  33                         + rel[i].r_offset;
  34
  35                 /* This is the symbol it is referring to.  Note that all
  36                    undefined symbols have been resolved.  */
  37                 sym = (Elf32_Sym *)sechdrs[symindex].sh_addr
  38                         + ELF32_R_SYM(rel[i].r_info);
  39                 value = sym->st_value + rel[i].r_addend;
  40
  41                 switch (ELF32_R_TYPE(rel[i].r_info)) {
  42                 case R_OR32_32:
  43                         *location = value;
  44                         break;
  45                 case R_OR32_CONST:
  46                         *((uint16_t *)location + 1) = value;
  47                         break;
  48                 case R_OR32_CONSTH:
  49                         *((uint16_t *)location + 1) = value >> 16;
  50                         break;
  51                 case R_OR32_JUMPTARG:
  52                         value -= (uint32_t)location;
  53                         value >>= 2;
  54                         value &= 0x03ffffff;
  55                         value |= *location & 0xfc000000;
  56                         *location = value;
  57                         break;
  58                 default:
  59                         pr_err("module %s: Unknown relocation: %u\n",
  60                                me->name, ELF32_R_TYPE(rel[i].r_info));
  61                         break;
  62                 }
  63         }
  64
  65         return 0;
  66 }