bfd/elf64-x86-64.c

   1 /* X86-64 specific support for 64-bit ELF
   2    Copyright 2000 Free Software Foundation, Inc.
   3    Contributed by Jan Hubicka <jh@suse.cz>.
   4
   5 This file is part of BFD, the Binary File Descriptor library.
   6
   7 This program is free software; you can redistribute it and/or modify
   8 it under the terms of the GNU General Public License as published by
   9 the Free Software Foundation; either version 2 of the License, or
  10 (at your option) any later version.
  11
  12 This program is distributed in the hope that it will be useful,
  13 but WITHOUT ANY WARRANTY; without even the implied warranty of
  14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15 GNU General Public License for more details.
  16
  17 You should have received a copy of the GNU General Public License
  18 along with this program; if not, write to the Free Software
  19 Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  */
  20
  21 #include "bfd.h"
  22 #include "sysdep.h"
  23 #include "libbfd.h"
  24 #include "elf-bfd.h"
  25
  26 #include "elf/x86-64.h"
  27
  28 /* We use only the RELA entries.  */
  29 #define USE_RELA
  30
  31 /* In case we're on a 32-bit machine, construct a 64-bit "-1" value.  */
  32 #define MINUS_ONE (~ (bfd_vma) 0)
  33
  34 /* The relocation "howto" table.  Order of fields:
  35    type, size, bitsize, pc_relative, complain_on_overflow, special_function,
  36    name, partial_inplace, src_mask, dst_pack, pcrel_offset  */
  37 static reloc_howto_type x86_64_elf_howto_table[] = {
  38   HOWTO(R_X86_64_NONE,          0,0, 0,false,0,complain_overflow_dont,    0, "R_X86_64_NONE",   false,0x00000000,0x00000000,false),
  39   HOWTO(R_X86_64_64,    0,4,64,false,0,complain_overflow_bitfield,0, "R_X86_64_64",     false,MINUS_ONE ,MINUS_ONE ,false),
  40   HOWTO(R_X86_64_PC32,          0,4,32,true ,0,complain_overflow_signed  ,0, "R_X86_64_PC32",   false,0xffffffff,0xffffffff,true),
  41   HOWTO(R_X86_64_GOT32,         0,4,32,false,0,complain_overflow_signed  ,0, "R_X86_64_GOT32",  false,0xffffffff,0xffffffff,false),
  42   HOWTO(R_X86_64_PLT32,         0,4,32,true ,0,complain_overflow_signed  ,0, "R_X86_64_PLT32",  false,0xffffffff,0xffffffff,true),
  43   HOWTO(R_X86_64_COPY,     0,4,32,false,0,complain_overflow_bitfield,0, "R_X86_64_COPY",   false,0xffffffff,0xffffffff,false),
  44   HOWTO(R_X86_64_GLOB_DAT, 0,4,64,false,0,complain_overflow_bitfield,0,"R_X86_64_GLOB_DAT",false,MINUS_ONE ,MINUS_ONE ,false),
  45   HOWTO(R_X86_64_RELATIVE ,0,4,64,false,0,complain_overflow_bitfield,0,"R_X86_64_RELATIVE",false,MINUS_ONE ,MINUS_ONE ,false),
  46   HOWTO(R_X86_64_JUMP_SLOT,0,4,64,false,0,complain_overflow_bitfield,0,"R_X86_64_JUMP_SLOT",false,MINUS_ONE,MINUS_ONE ,false),
  47   HOWTO(R_X86_64_GOTPCREL, 0,4,32,true, 0,complain_overflow_signed  ,0, "R_X86_64_PCREL",  false,0xffffffff,0xffffffff,true),
  48   HOWTO(R_X86_64_32,    0,4,32,false,0,complain_overflow_unsigned,0, "R_X86_64_32",     false,0xffffffff,0xffffffff,false),
  49   HOWTO(R_X86_64_32S,   0,4,32,false,0,complain_overflow_signed,  0, "R_X86_64_32S",    false,0xffffffff,0xffffffff,false),
  50   HOWTO(R_X86_64_16,    0,1,16,false,0,complain_overflow_bitfield,0, "R_X86_64_16",     false,0xffff    ,0xffff,    false),
  51   HOWTO(R_X86_64_PC16,          0,1,16,true ,0,complain_overflow_bitfield,0, "R_X86_64_PC16",   false,0xffff    ,0xffff,    true),
  52   HOWTO(R_X86_64_8,     0,0, 8,false,0,complain_overflow_signed  ,0, "R_X86_64_8",      false,0xff      ,0xff,      false),
  53   HOWTO(R_X86_64_PC8,   0,0, 8,true ,0,complain_overflow_signed  ,0, "R_X86_64_PC8",    false,0xff      ,0xff,      true),
  54 };
  55
  56 /* Map BFD relocs to the x86_64 elf relocs.  */
  57 struct elf_reloc_map {
  58   bfd_reloc_code_real_type bfd_reloc_val;
  59   unsigned char elf_reloc_val;
  60 };
  61
  62 static CONST struct elf_reloc_map x86_64_reloc_map[] =
  63 {
  64   { BFD_RELOC_NONE,           R_X86_64_NONE, },
  65   { BFD_RELOC_64,             R_X86_64_64,   },
  66   { BFD_RELOC_32_PCREL,               R_X86_64_PC32, },
  67   { BFD_RELOC_X86_64_GOT32,   R_X86_64_GOT32,},
  68   { BFD_RELOC_X86_64_PLT32,   R_X86_64_PLT32,},
  69   { BFD_RELOC_X86_64_COPY,    R_X86_64_COPY, },
  70   { BFD_RELOC_X86_64_GLOB_DAT,        R_X86_64_GLOB_DAT, },
  71   { BFD_RELOC_X86_64_JUMP_SLOT,       R_X86_64_JUMP_SLOT, },
  72   { BFD_RELOC_X86_64_RELATIVE,        R_X86_64_RELATIVE, },
  73   { BFD_RELOC_X86_64_GOTPCREL,        R_X86_64_GOTPCREL, },
  74   { BFD_RELOC_32,             R_X86_64_32, },
  75   { BFD_RELOC_X86_64_32S,     R_X86_64_32S, },
  76   { BFD_RELOC_16,             R_X86_64_16, },
  77   { BFD_RELOC_16_PCREL,               R_X86_64_PC16, },
  78   { BFD_RELOC_8,              R_X86_64_8, },
  79   { BFD_RELOC_8_PCREL,                R_X86_64_PC8, },
  80 };
  81
  82 static reloc_howto_type *elf64_x86_64_reloc_type_lookup
  83   PARAMS ((bfd *, bfd_reloc_code_real_type));
  84 static void elf64_x86_64_info_to_howto
  85   PARAMS ((bfd *, arelent *, Elf64_Internal_Rela *));
  86 static struct bfd_link_hash_table *elf64_x86_64_link_hash_table_create
  87   PARAMS ((bfd *));
  88 static boolean elf64_x86_64_relocate_section
  89   PARAMS ((bfd *, struct bfd_link_info *, bfd *, asection *, bfd_byte *,
  90          Elf_Internal_Rela *, Elf_Internal_Sym *, asection **));
  91
  92 /* Given a BFD reloc type, return a HOWTO structure.  */
  93 static reloc_howto_type *
  94 elf64_x86_64_reloc_type_lookup (abfd, code)
  95      bfd *abfd ATTRIBUTE_UNUSED;
  96      bfd_reloc_code_real_type code;
  97 {
  98   unsigned int i;
  99   for (i = 0; i < sizeof (x86_64_reloc_map) / sizeof (struct elf_reloc_map);
 100        i++)
 101     {
 102       if (x86_64_reloc_map[i].bfd_reloc_val == code)
 103         return &x86_64_elf_howto_table[(int)
 104                                        x86_64_reloc_map[i].elf_reloc_val];
 105     }
 106   return 0;
 107 }
 108
 109 /* Given an x86_64 ELF reloc type, fill in an arelent structure.  */
 110
 111 static void
 112 elf64_x86_64_info_to_howto (abfd, cache_ptr, dst)
 113      bfd *abfd ATTRIBUTE_UNUSED;
 114      arelent *cache_ptr;
 115      Elf64_Internal_Rela *dst;
 116 {
 117   unsigned r_type;
 118
 119   r_type = ELF64_R_TYPE (dst->r_info);
 120   BFD_ASSERT (r_type < (unsigned int) R_X86_64_max);
 121   cache_ptr->howto = &x86_64_elf_howto_table[r_type];
 122   BFD_ASSERT (r_type == cache_ptr->howto->type);
 123 }
 124
 125 /* Hash table functions - these will be used by dynamic linking code and
 126    right now they are needed to keep ld happy.  */
 127
 128 /* x86_64  ELF linker hash table.  */
 129
 130 struct elf64_x86_64_link_hash_table {
 131   struct elf_link_hash_table root;
 132 };
 133
 134 /* Get the X86-64 ELF linker hash table from a link_info structure.  */
 135
 136 #define elf64_x86_64_hash_table(p) \
 137   ((struct elf64_x86_64_link_hash_table *) ((p)->hash))
 138
 139 /* Create an X86-64 ELF linker hash table.  */
 140
 141 static struct bfd_link_hash_table *
 142 elf64_x86_64_link_hash_table_create (abfd)
 143      bfd *abfd;
 144 {
 145   struct elf64_x86_64_link_hash_table *ret;
 146
 147   ret = ((struct elf64_x86_64_link_hash_table *)
 148          bfd_alloc (abfd, sizeof (struct elf64_x86_64_link_hash_table)));
 149   if (ret == (struct elf64_x86_64_link_hash_table *) NULL)
 150     return NULL;
 151
 152   if (! _bfd_elf_link_hash_table_init (&ret->root, abfd,
 153                                      _bfd_elf_link_hash_newfunc))
 154     {
 155       bfd_release (abfd, ret);
 156       return NULL;
 157     }
 158
 159   return &ret->root.root;
 160 }
 161
 162 boolean
 163 elf64_x86_64_elf_object_p (abfd)
 164      bfd *abfd;
 165 {
 166   /* Set the right machine number for an x86-64 elf64 file.  */
 167   bfd_default_set_arch_mach (abfd, bfd_arch_i386, bfd_mach_x86_64);
 168   return true;
 169 }
 170
 171 /* Relocate an x86_64 ELF section.  */
 172
 173 static boolean
 174 elf64_x86_64_relocate_section (output_bfd, info, input_bfd, input_section,
 175                              contents, relocs, local_syms, local_sections)
 176      bfd *output_bfd;
 177      struct bfd_link_info *info;
 178      bfd *input_bfd;
 179      asection *input_section;
 180      bfd_byte *contents;
 181      Elf_Internal_Rela *relocs;
 182      Elf_Internal_Sym *local_syms;
 183      asection **local_sections;
 184 {
 185   bfd *dynobj;
 186   Elf_Internal_Shdr *symtab_hdr;
 187   struct elf_link_hash_entry **sym_hashes;
 188   bfd_vma *local_got_offsets;
 189   asection *sreloc;
 190   Elf_Internal_Rela *rel;
 191   Elf_Internal_Rela *relend;
 192
 193   dynobj = elf_hash_table (info)->dynobj;
 194   symtab_hdr = &elf_tdata (input_bfd)->symtab_hdr;
 195   sym_hashes = elf_sym_hashes (input_bfd);
 196   local_got_offsets = elf_local_got_offsets (input_bfd);
 197
 198   sreloc = NULL;
 199   if (dynobj != NULL)
 200     abort ();
 201
 202   rel = relocs;
 203   relend = relocs + input_section->reloc_count;
 204   for (; rel < relend; rel++)
 205     {
 206       int r_type;
 207       reloc_howto_type *howto;
 208       unsigned long r_symndx;
 209       struct elf_link_hash_entry *h;
 210       Elf_Internal_Sym *sym;
 211       asection *sec;
 212       bfd_vma relocation;
 213       bfd_reloc_status_type r;
 214       unsigned int indx;
 215
 216       r_type = ELF64_R_TYPE (rel->r_info);
 217
 218       if ((indx = (unsigned) r_type) >= R_X86_64_max)
 219         {
 220           bfd_set_error (bfd_error_bad_value);
 221           return false;
 222         }
 223       howto = x86_64_elf_howto_table + indx;
 224
 225       r_symndx = ELF64_R_SYM (rel->r_info);
 226
 227       if (info->relocateable)
 228         {
 229           /* This is a relocateable link.  We don't have to change
 230              anything, unless the reloc is against a section symbol,
 231              in which case we have to adjust according to where the
 232              section symbol winds up in the output section.  */
 233           if (r_symndx < symtab_hdr->sh_info)
 234             {
 235               sym = local_syms + r_symndx;
 236               if (ELF_ST_TYPE (sym->st_info) == STT_SECTION)
 237                 {
 238                   sec = local_sections[r_symndx];
 239                   rel->r_addend += sec->output_offset + sym->st_value;
 240                 }
 241             }
 242
 243           continue;
 244         }
 245
 246       /* This is a final link.  */
 247       h = NULL;
 248       sym = NULL;
 249       sec = NULL;
 250       if (r_symndx < symtab_hdr->sh_info)
 251         {
 252           sym = local_syms + r_symndx;
 253           sec = local_sections[r_symndx];
 254           relocation = (sec->output_section->vma
 255                         + sec->output_offset
 256                         + sym->st_value);
 257         }
 258       else
 259         {
 260           h = sym_hashes[r_symndx - symtab_hdr->sh_info];
 261           while (h->root.type == bfd_link_hash_indirect
 262                  || h->root.type == bfd_link_hash_warning)
 263             h = (struct elf_link_hash_entry *) h->root.u.i.link;
 264           if (h->root.type == bfd_link_hash_defined
 265               || h->root.type == bfd_link_hash_defweak)
 266             {
 267               sec = h->root.u.def.section;
 268               if (sec->output_section == NULL)
 269                 {
 270                   (*_bfd_error_handler)
 271                     (_("%s: warning: unresolvable relocation against symbol `%s' from %s section"),
 272                      bfd_get_filename (input_bfd), h->root.root.string,
 273                      bfd_get_section_name (input_bfd, input_section));
 274                   relocation = 0;
 275                 }
 276               else
 277                 relocation = (h->root.u.def.value
 278                               + sec->output_section->vma
 279                               + sec->output_offset);
 280             }
 281           else if (h->root.type == bfd_link_hash_undefweak)
 282             relocation = 0;
 283           else
 284             {
 285               if (! ((*info->callbacks->undefined_symbol)
 286                      (info, h->root.root.string, input_bfd,
 287                       input_section, rel->r_offset,
 288                       (!info->shared || info->no_undefined
 289                        || ELF_ST_VISIBILITY (h->other)))))
 290                 return false;
 291               relocation = 0;
 292             }
 293         }
 294       /* This function should support shared objects, but don't.  */
 295       if (info->shared)
 296         abort ();
 297
 298       r = _bfd_final_link_relocate (howto, input_bfd, input_section,
 299                                     contents, rel->r_offset,
 300                                     relocation, rel->r_addend);
 301
 302       if (r != bfd_reloc_ok)
 303         {
 304           switch (r)
 305             {
 306             default:
 307             case bfd_reloc_outofrange:
 308               abort ();
 309             case bfd_reloc_overflow:
 310               {
 311                 const char *name;
 312
 313                 if (h != NULL)
 314                   name = h->root.root.string;
 315                 else
 316                   {
 317                     name = bfd_elf_string_from_elf_section (input_bfd,
 318                                                             symtab_hdr->sh_link,
 319                                                             sym->st_name);
 320                     if (name == NULL)
 321                       return false;
 322                     if (*name == '\0')
 323                       name = bfd_section_name (input_bfd, sec);
 324                   }
 325                 if (! ((*info->callbacks->reloc_overflow)
 326                        (info, name, howto->name, (bfd_vma) 0,
 327                         input_bfd, input_section, rel->r_offset)))
 328                   return false;
 329               }
 330               break;
 331             }
 332         }
 333     }
 334   return true;
 335 }
 336
 337 #define TARGET_LITTLE_SYM             bfd_elf64_x86_64_vec
 338 #define TARGET_LITTLE_NAME            "elf64-x86-64"
 339 #define ELF_ARCH                      bfd_arch_i386
 340 #define ELF_MACHINE_CODE              EM_X86_64
 341 #define ELF_MAXPAGESIZE                       0x100000
 342 #define elf_info_to_howto             elf64_x86_64_info_to_howto
 343 #define bfd_elf64_bfd_reloc_type_lookup       elf64_x86_64_reloc_type_lookup
 344 #define elf_backend_object_p            elf64_x86_64_elf_object_p
 345 #define elf_backend_relocate_section  elf64_x86_64_relocate_section
 346 #define bfd_elf64_bfd_link_hash_table_create elf64_x86_64_link_hash_table_create
 347
 348 #include "elf64-target.h"