arch/x86/lib/reloc_x86_64_efi.c

   1 // SPDX-License-Identifier: BSD-3-Clause
   2 /*
   3  * reloc_x86_64.c - position independent x86_64 ELF shared object relocator
   4  * Copyright (C) 1999 Hewlett-Packard Co.
   5  * Contributed by David Mosberger <davidm@hpl.hp.com>.
   6  * Copyright (C) 2005 Intel Co.
   7  * Contributed by Fenghua Yu <fenghua.yu@intel.com>.
   8  *
   9  * All rights reserved.
  10  */
  11
  12 #include <common.h>
  13 #include <efi.h>
  14 #include <elf.h>
  15 #include <asm/elf.h>
  16
  17 efi_status_t _relocate(long ldbase, Elf64_Dyn *dyn, efi_handle_t image,
  18                        struct efi_system_table *systab)
  19 {
  20         long relsz = 0, relent = 0;
  21         Elf64_Rel *rel = 0;
  22         unsigned long *addr;
  23         int i;
  24
  25         for (i = 0; dyn[i].d_tag != DT_NULL; ++i) {
  26                 switch (dyn[i].d_tag) {
  27                 case DT_RELA:
  28                         rel = (Elf64_Rel *)
  29                                 ((unsigned long)dyn[i].d_un.d_ptr + ldbase);
  30                         break;
  31                 case DT_RELASZ:
  32                         relsz = dyn[i].d_un.d_val;
  33                         break;
  34                 case DT_RELAENT:
  35                         relent = dyn[i].d_un.d_val;
  36                         break;
  37                 default:
  38                         break;
  39                 }
  40         }
  41
  42         if (!rel && relent == 0)
  43                 return EFI_SUCCESS;
  44
  45         if (!rel || relent == 0)
  46                 return EFI_LOAD_ERROR;
  47
  48         while (relsz > 0) {
  49                 /* apply the relocs */
  50                 switch (ELF64_R_TYPE(rel->r_info)) {
  51                 case R_X86_64_NONE:
  52                         break;
  53                 case R_X86_64_RELATIVE:
  54                         addr = (unsigned long *)(ldbase + rel->r_offset);
  55                         *addr += ldbase;
  56                         break;
  57                 default:
  58                         break;
  59                 }
  60                 rel = (Elf64_Rel *)((char *)rel + relent);
  61                 relsz -= relent;
  62         }
  63
  64         return EFI_SUCCESS;
  65 }