usr/src/boot/sys/boot/efi/loader/reloc.c

   1 /*-
   2  * Copyright (c) 2008-2010 Rui Paulo <rpaulo@FreeBSD.org>
   3  * All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice, this list of conditions and the following disclaimer.
  10  * 2. Redistributions in binary form must reproduce the above copyright
  11  *    notice, this list of conditions and the following disclaimer in the
  12  *    documentation and/or other materials provided with the distribution.
  13  *
  14  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  15  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  16  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  17  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  18  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  19  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  20  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  21  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  22  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  23  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  24  * SUCH DAMAGE.
  25  */
  26
  27 #include <sys/cdefs.h>
  28 __FBSDID("$FreeBSD$");
  29
  30 #include <sys/types.h>
  31 #include <elf.h>
  32 #include <efi.h>
  33 #include <bootstrap.h>
  34
  35 #if defined(__aarch64__)
  36 #define ElfW_Rel        Elf64_Rela
  37 #define ElfW_Dyn        Elf64_Dyn
  38 #define ELFW_R_TYPE     ELF64_R_TYPE
  39 #define ELF_RELA
  40 #elif defined(__arm__) || defined(__i386__)
  41 #define ElfW_Rel        Elf32_Rel
  42 #define ElfW_Dyn        Elf32_Dyn
  43 #define ELFW_R_TYPE     ELF32_R_TYPE
  44 #elif defined(__amd64__)
  45 #define ElfW_Rel        Elf64_Rel
  46 #define ElfW_Dyn        Elf64_Dyn
  47 #define ELFW_R_TYPE     ELF64_R_TYPE
  48 #else
  49 #error architecture not supported
  50 #endif
  51 #if defined(__aarch64__)
  52 #define RELOC_TYPE_NONE         R_AARCH64_NONE
  53 #define RELOC_TYPE_RELATIVE     R_AARCH64_RELATIVE
  54 #elif defined(__amd64__)
  55 #define RELOC_TYPE_NONE         R_X86_64_NONE
  56 #define RELOC_TYPE_RELATIVE     R_X86_64_RELATIVE
  57 #elif defined(__arm__)
  58 #define RELOC_TYPE_NONE         R_ARM_NONE
  59 #define RELOC_TYPE_RELATIVE     R_ARM_RELATIVE
  60 #elif defined(__i386__)
  61 #define RELOC_TYPE_NONE         R_386_NONE
  62 #define RELOC_TYPE_RELATIVE     R_386_RELATIVE
  63 #endif
  64
  65 /*
  66  * A simple relocator for EFI binaries.
  67  */
  68 EFI_STATUS
  69 _reloc(unsigned long ImageBase, ElfW_Dyn *dynamic, EFI_HANDLE image_handle,
  70     EFI_SYSTEM_TABLE *system_table)
  71 {
  72         unsigned long relsz, relent;
  73         unsigned long *newaddr;
  74         ElfW_Rel *rel;
  75         ElfW_Dyn *dynp;
  76
  77         /*
  78          * Find the relocation address, its size and the relocation entry.
  79          */
  80         relsz = 0;
  81         relent = 0;
  82         for (dynp = dynamic; dynp->d_tag != DT_NULL; dynp++) {
  83                 switch (dynp->d_tag) {
  84                 case DT_REL:
  85                 case DT_RELA:
  86                         rel = (ElfW_Rel *) ((unsigned long) dynp->d_un.d_ptr +
  87                             ImageBase);
  88                         break;
  89                 case DT_RELSZ:
  90                 case DT_RELASZ:
  91                         relsz = dynp->d_un.d_val;
  92                         break;
  93                 case DT_RELENT:
  94                 case DT_RELAENT:
  95                         relent = dynp->d_un.d_val;
  96                         break;
  97                 default:
  98                         break;
  99                 }
 100         }
 101
 102         /*
 103          * Perform the actual relocation.
 104          */
 105         for (; relsz > 0; relsz -= relent) {
 106                 switch (ELFW_R_TYPE(rel->r_info)) {
 107                 case RELOC_TYPE_NONE:
 108                         /* No relocation needs be performed. */
 109                         break;
 110
 111                 case RELOC_TYPE_RELATIVE:
 112                         /* Address relative to the base address. */
 113                         newaddr = (unsigned long *)(ImageBase + rel->r_offset);
 114                         *newaddr += ImageBase;
 115                         /* Add the addend when the ABI uses them */
 116 #ifdef ELF_RELA
 117                         *newaddr += rel->r_addend;
 118 #endif
 119                         break;
 120                 default:
 121                         /* XXX: do we need other relocations ? */
 122                         break;
 123                 }
 124                 rel = (ElfW_Rel *) ((caddr_t) rel + relent);
 125         }
 126
 127         return (EFI_SUCCESS);
 128 }