bfd/elf32-mt.c

   1 /* Morpho Technologies MT specific support for 32-bit ELF
   2    Copyright (C) 2001-2023 Free Software Foundation, Inc.
   3
   4    This file is part of BFD, the Binary File Descriptor library.
   5
   6    This program is free software; you can redistribute it and/or modify
   7    it under the terms of the GNU General Public License as published by
   8    the Free Software Foundation; either version 3 of the License, or
   9    (at your option) any later version.
  10
  11    This program is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14    GNU General Public License for more details.
  15
  16    You should have received a copy of the GNU General Public License
  17    along with this program; if not, write to the Free Software
  18    Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
  19    MA 02110-1301, USA.  */
  20
  21 #include "sysdep.h"
  22 #include "bfd.h"
  23 #include "libbfd.h"
  24 #include "elf-bfd.h"
  25 #include "elf/mt.h"
  26
  27 /* Prototypes.  */
  28 static reloc_howto_type * mt_reloc_type_lookup
  29   (bfd *, bfd_reloc_code_real_type);
  30
  31 static bool mt_info_to_howto_rela
  32   (bfd *, arelent *, Elf_Internal_Rela *);
  33
  34 static bfd_reloc_status_type mt_elf_relocate_hi16
  35   (bfd *, Elf_Internal_Rela *, bfd_byte *, bfd_vma);
  36
  37 static bfd_reloc_status_type mt_final_link_relocate
  38   (reloc_howto_type *, bfd *, asection *, bfd_byte *,
  39    Elf_Internal_Rela *, bfd_vma);
  40
  41 static int mt_elf_relocate_section
  42   (bfd *, struct bfd_link_info *, bfd *, asection *, bfd_byte *,
  43    Elf_Internal_Rela *, Elf_Internal_Sym *, asection **);
  44
  45 /* Relocation tables.  */
  46 static reloc_howto_type mt_elf_howto_table [] =
  47 {
  48   /* This reloc does nothing.  */
  49   HOWTO (R_MT_NONE,           /* type */
  50           0,                      /* rightshift */
  51           0,                      /* size */
  52           0,                      /* bitsize */
  53           false,                  /* pc_relative */
  54           0,                      /* bitpos */
  55           complain_overflow_dont, /* complain_on_overflow */
  56           bfd_elf_generic_reloc,  /* special_function */
  57           "R_MT_NONE",          /* name */
  58           false,                  /* partial_inplace */
  59           0 ,                     /* src_mask */
  60           0,                      /* dst_mask */
  61           false),                 /* pcrel_offset */
  62
  63   /* A 16 bit absolute relocation.  */
  64   HOWTO (R_MT_16,             /* type */
  65           0,                      /* rightshift */
  66           4,                      /* size */
  67           16,                     /* bitsize */
  68           false,                  /* pc_relative */
  69           0,                      /* bitpos */
  70           complain_overflow_dont, /* complain_on_overflow */
  71           bfd_elf_generic_reloc,  /* special_function */
  72           "R_MT_16",            /* name */
  73           false,                  /* partial_inplace */
  74           0 ,                     /* src_mask */
  75           0xffff,                 /* dst_mask */
  76           false),                 /* pcrel_offset */
  77
  78   /* A 32 bit absolute relocation.  */
  79   HOWTO (R_MT_32,             /* type */
  80           0,                      /* rightshift */
  81           4,                      /* size */
  82           32,                     /* bitsize */
  83           false,                  /* pc_relative */
  84           0,                      /* bitpos */
  85           complain_overflow_dont, /* complain_on_overflow */
  86           bfd_elf_generic_reloc,  /* special_function */
  87           "R_MT_32",            /* name */
  88           false,                  /* partial_inplace */
  89           0 ,                     /* src_mask */
  90           0xffffffff,             /* dst_mask */
  91           false),                 /* pcrel_offset */
  92
  93   /* A 32 bit pc-relative relocation.  */
  94   HOWTO (R_MT_32_PCREL,       /* type */
  95           0,                      /* rightshift */
  96           4,                      /* size */
  97           32,                     /* bitsize */
  98           true,                   /* pc_relative */
  99           0,                      /* bitpos */
 100           complain_overflow_dont, /* complain_on_overflow */
 101           bfd_elf_generic_reloc,  /* special_function */
 102           "R_MT_32_PCREL",    /* name */
 103           false,                  /* partial_inplace */
 104           0 ,                     /* src_mask */
 105           0xffffffff,             /* dst_mask */
 106           true),                  /* pcrel_offset */
 107
 108   /* A 16 bit pc-relative relocation.  */
 109   HOWTO (R_MT_PC16,           /* type */
 110           0,                      /* rightshift */
 111           4,                      /* size */
 112           16,                     /* bitsize */
 113           true,                   /* pc_relative */
 114           0,                      /* bitpos */
 115           complain_overflow_signed, /* complain_on_overflow */
 116           bfd_elf_generic_reloc,  /* special_function */
 117           "R_MT_PC16",          /* name */
 118           false,                  /* partial_inplace */
 119           0,                      /* src_mask */
 120           0xffff,                 /* dst_mask */
 121           true),                  /* pcrel_offset */
 122
 123   /* high 16 bits of symbol value.  */
 124   HOWTO (R_MT_HI16,          /* type */
 125          0,                     /* rightshift */
 126          4,                     /* size */
 127          16,                    /* bitsize */
 128          false,                 /* pc_relative */
 129          0,                     /* bitpos */
 130          complain_overflow_dont, /* complain_on_overflow */
 131          bfd_elf_generic_reloc, /* special_function */
 132          "R_MT_HI16",        /* name */
 133          false,                  /* partial_inplace */
 134          0xffff0000,            /* src_mask */
 135          0xffff0000,            /* dst_mask */
 136          false),                /* pcrel_offset */
 137
 138   /* Low 16 bits of symbol value.  */
 139   HOWTO (R_MT_LO16,          /* type */
 140          0,                     /* rightshift */
 141          4,                     /* size */
 142          16,                    /* bitsize */
 143          false,                 /* pc_relative */
 144          0,                     /* bitpos */
 145          complain_overflow_dont, /* complain_on_overflow */
 146          bfd_elf_generic_reloc, /* special_function */
 147          "R_MT_LO16",        /* name */
 148          false,                  /* partial_inplace */
 149          0xffff,                /* src_mask */
 150          0xffff,                /* dst_mask */
 151          false),                /* pcrel_offset */
 152 };
 153
 154 /* Map BFD reloc types to MT ELF reloc types.  */
 155
 156 static reloc_howto_type *
 157 mt_reloc_type_lookup
 158     (bfd *                    abfd ATTRIBUTE_UNUSED,
 159      bfd_reloc_code_real_type code)
 160 {
 161   /* Note that the mt_elf_howto_table is indxed by the R_
 162      constants.  Thus, the order that the howto records appear in the
 163      table *must* match the order of the relocation types defined in
 164      include/elf/mt.h.  */
 165
 166   switch (code)
 167     {
 168     case BFD_RELOC_NONE:
 169       return &mt_elf_howto_table[ (int) R_MT_NONE];
 170     case BFD_RELOC_16:
 171       return &mt_elf_howto_table[ (int) R_MT_16];
 172     case BFD_RELOC_32:
 173       return &mt_elf_howto_table[ (int) R_MT_32];
 174     case BFD_RELOC_32_PCREL:
 175       return &mt_elf_howto_table[ (int) R_MT_32_PCREL];
 176     case BFD_RELOC_16_PCREL:
 177       return &mt_elf_howto_table[ (int) R_MT_PC16];
 178     case BFD_RELOC_HI16:
 179       return &mt_elf_howto_table[ (int) R_MT_HI16];
 180     case BFD_RELOC_LO16:
 181       return &mt_elf_howto_table[ (int) R_MT_LO16];
 182
 183     default:
 184       /* Pacify gcc -Wall.  */
 185       return NULL;
 186     }
 187   return NULL;
 188 }
 189
 190 static reloc_howto_type *
 191 mt_reloc_name_lookup (bfd *abfd ATTRIBUTE_UNUSED,
 192                       const char *r_name)
 193 {
 194   unsigned int i;
 195
 196   for (i = 0;
 197        i < sizeof (mt_elf_howto_table) / sizeof (mt_elf_howto_table[0]);
 198        i++)
 199     if (mt_elf_howto_table[i].name != NULL
 200         && strcasecmp (mt_elf_howto_table[i].name, r_name) == 0)
 201       return &mt_elf_howto_table[i];
 202
 203   return NULL;
 204 }
 205
 206 bfd_reloc_status_type
 207 mt_elf_relocate_hi16
 208     (bfd *               input_bfd,
 209      Elf_Internal_Rela * relhi,
 210      bfd_byte *          contents,
 211      bfd_vma             value)
 212 {
 213   bfd_vma insn;
 214
 215   insn = bfd_get_32 (input_bfd, contents + relhi->r_offset);
 216
 217   value += relhi->r_addend;
 218   value >>= 16;
 219   insn = ((insn & ~0xFFFF) | value);
 220
 221   bfd_put_32 (input_bfd, insn, contents + relhi->r_offset);
 222   return bfd_reloc_ok;
 223 }
 224 \f
 225 /* XXX: The following code is the result of a cut&paste.  This unfortunate
 226    practice is very widespread in the various target back-end files.  */
 227
 228 /* Set the howto pointer for a MT ELF reloc.  */
 229
 230 static bool
 231 mt_info_to_howto_rela (bfd *abfd,
 232                        arelent *cache_ptr,
 233                        Elf_Internal_Rela *dst)
 234 {
 235   unsigned int r_type;
 236
 237   r_type = ELF32_R_TYPE (dst->r_info);
 238   if (r_type >= (unsigned int) R_MT_max)
 239     {
 240       /* xgettext:c-format */
 241       _bfd_error_handler (_("%pB: unsupported relocation type %#x"),
 242                           abfd, r_type);
 243       bfd_set_error (bfd_error_bad_value);
 244       return false;
 245     }
 246   cache_ptr->howto = & mt_elf_howto_table [r_type];
 247   return true;
 248 }
 249
 250 /* Perform a single relocation.  By default we use the standard BFD
 251    routines.  */
 252
 253 static bfd_reloc_status_type
 254 mt_final_link_relocate
 255     (reloc_howto_type *  howto,
 256      bfd *               input_bfd,
 257      asection *          input_section,
 258      bfd_byte *          contents,
 259      Elf_Internal_Rela * rel,
 260      bfd_vma             relocation)
 261 {
 262   return _bfd_final_link_relocate (howto, input_bfd, input_section,
 263                                    contents, rel->r_offset,
 264                                    relocation, rel->r_addend);
 265 }
 266
 267 /* Relocate a MT ELF section.
 268    There is some attempt to make this function usable for many architectures,
 269    both USE_REL and USE_RELA ['twould be nice if such a critter existed],
 270    if only to serve as a learning tool.
 271
 272    The RELOCATE_SECTION function is called by the new ELF backend linker
 273    to handle the relocations for a section.
 274
 275    The relocs are always passed as Rela structures; if the section
 276    actually uses Rel structures, the r_addend field will always be
 277    zero.
 278
 279    This function is responsible for adjusting the section contents as
 280    necessary, and (if using Rela relocs and generating a relocatable
 281    output file) adjusting the reloc addend as necessary.
 282
 283    This function does not have to worry about setting the reloc
 284    address or the reloc symbol index.
 285
 286    LOCAL_SYMS is a pointer to the swapped in local symbols.
 287
 288    LOCAL_SECTIONS is an array giving the section in the input file
 289    corresponding to the st_shndx field of each local symbol.
 290
 291    The global hash table entry for the global symbols can be found
 292    via elf_sym_hashes (input_bfd).
 293
 294    When generating relocatable output, this function must handle
 295    STB_LOCAL/STT_SECTION symbols specially.  The output symbol is
 296    going to be the section symbol corresponding to the output
 297    section, which means that the addend must be adjusted
 298    accordingly.  */
 299
 300 static int
 301 mt_elf_relocate_section
 302     (bfd *                   output_bfd ATTRIBUTE_UNUSED,
 303      struct bfd_link_info *  info,
 304      bfd *                   input_bfd,
 305      asection *              input_section,
 306      bfd_byte *              contents,
 307      Elf_Internal_Rela *     relocs,
 308      Elf_Internal_Sym *      local_syms,
 309      asection **             local_sections)
 310 {
 311   Elf_Internal_Shdr *           symtab_hdr;
 312   struct elf_link_hash_entry ** sym_hashes;
 313   Elf_Internal_Rela *           rel;
 314   Elf_Internal_Rela *           relend;
 315
 316   symtab_hdr = & elf_tdata (input_bfd)->symtab_hdr;
 317   sym_hashes = elf_sym_hashes (input_bfd);
 318   relend     = relocs + input_section->reloc_count;
 319
 320   for (rel = relocs; rel < relend; rel ++)
 321     {
 322       reloc_howto_type *           howto;
 323       unsigned long                r_symndx;
 324       Elf_Internal_Sym *           sym;
 325       asection *                   sec;
 326       struct elf_link_hash_entry * h;
 327       bfd_vma                      relocation;
 328       bfd_reloc_status_type        r;
 329       const char *                 name = NULL;
 330       int                          r_type;
 331
 332       r_type = ELF32_R_TYPE (rel->r_info);
 333
 334       r_symndx = ELF32_R_SYM (rel->r_info);
 335
 336       howto  = mt_elf_howto_table + ELF32_R_TYPE (rel->r_info);
 337       h      = NULL;
 338       sym    = NULL;
 339       sec    = NULL;
 340
 341       if (r_symndx < symtab_hdr->sh_info)
 342         {
 343           sym = local_syms + r_symndx;
 344           sec = local_sections [r_symndx];
 345           relocation = _bfd_elf_rela_local_sym (output_bfd, sym, &sec, rel);
 346
 347           name = bfd_elf_string_from_elf_section
 348             (input_bfd, symtab_hdr->sh_link, sym->st_name);
 349           name = name == NULL ? bfd_section_name (sec) : name;
 350         }
 351       else
 352         {
 353           bool unresolved_reloc;
 354           bool warned, ignored;
 355
 356           RELOC_FOR_GLOBAL_SYMBOL (info, input_bfd, input_section, rel,
 357                                    r_symndx, symtab_hdr, sym_hashes,
 358                                    h, sec, relocation,
 359                                    unresolved_reloc, warned, ignored);
 360
 361           name = h->root.root.string;
 362         }
 363
 364       if (sec != NULL && discarded_section (sec))
 365         RELOC_AGAINST_DISCARDED_SECTION (info, input_bfd, input_section,
 366                                          rel, 1, relend, howto, 0, contents);
 367
 368       if (bfd_link_relocatable (info))
 369         continue;
 370
 371       /* Finally, the sole MT-specific part.  */
 372       switch (r_type)
 373         {
 374         case R_MT_HI16:
 375           r = mt_elf_relocate_hi16 (input_bfd, rel, contents, relocation);
 376           break;
 377         default:
 378           r = mt_final_link_relocate (howto, input_bfd, input_section,
 379                                           contents, rel, relocation);
 380           break;
 381         }
 382
 383
 384       if (r != bfd_reloc_ok)
 385         {
 386           const char * msg = (const char *) NULL;
 387
 388           switch (r)
 389             {
 390             case bfd_reloc_overflow:
 391               (*info->callbacks->reloc_overflow)
 392                 (info, (h ? &h->root : NULL), name, howto->name, (bfd_vma) 0,
 393                  input_bfd, input_section, rel->r_offset);
 394               break;
 395
 396             case bfd_reloc_undefined:
 397               (*info->callbacks->undefined_symbol)
 398                 (info, name, input_bfd, input_section, rel->r_offset, true);
 399               break;
 400
 401             case bfd_reloc_outofrange:
 402               msg = _("internal error: out of range error");
 403               break;
 404
 405             case bfd_reloc_dangerous:
 406               msg = _("internal error: dangerous relocation");
 407               break;
 408
 409             default:
 410               msg = _("internal error: unknown error");
 411               break;
 412             }
 413
 414           if (msg)
 415             (*info->callbacks->warning) (info, msg, name, input_bfd,
 416                                          input_section, rel->r_offset);
 417         }
 418     }
 419
 420   return true;
 421 }
 422
 423 /* Look through the relocs for a section during the first phase.
 424    Since we don't do .gots or .plts, we just need to consider the
 425    virtual table relocs for gc.  */
 426
 427 static bool
 428 mt_elf_check_relocs (bfd *abfd,
 429                      struct bfd_link_info *info,
 430                      asection *sec,
 431                      const Elf_Internal_Rela *relocs)
 432 {
 433   Elf_Internal_Shdr *symtab_hdr;
 434   struct elf_link_hash_entry **sym_hashes;
 435   const Elf_Internal_Rela *rel;
 436   const Elf_Internal_Rela *rel_end;
 437
 438   if (bfd_link_relocatable (info))
 439     return true;
 440
 441   symtab_hdr = &elf_tdata (abfd)->symtab_hdr;
 442   sym_hashes = elf_sym_hashes (abfd);
 443
 444   rel_end = relocs + sec->reloc_count;
 445   for (rel = relocs; rel < rel_end; rel++)
 446     {
 447       struct elf_link_hash_entry *h;
 448       unsigned long r_symndx;
 449
 450       r_symndx = ELF32_R_SYM (rel->r_info);
 451       if (r_symndx < symtab_hdr->sh_info)
 452         h = NULL;
 453       else
 454         {
 455           h = sym_hashes[r_symndx - symtab_hdr->sh_info];
 456           while (h->root.type == bfd_link_hash_indirect
 457                  || h->root.type == bfd_link_hash_warning)
 458             h = (struct elf_link_hash_entry *) h->root.u.i.link;
 459         }
 460     }
 461
 462   return true;
 463 }
 464
 465 /* Return the MACH for an e_flags value.  */
 466
 467 static int
 468 elf32_mt_machine (bfd *abfd)
 469 {
 470   switch (elf_elfheader (abfd)->e_flags & EF_MT_CPU_MASK)
 471     {
 472     case EF_MT_CPU_MRISC:       return bfd_mach_ms1;
 473     case EF_MT_CPU_MRISC2:      return bfd_mach_mrisc2;
 474     case EF_MT_CPU_MS2:         return bfd_mach_ms2;
 475     }
 476
 477   return bfd_mach_ms1;
 478 }
 479
 480 static bool
 481 mt_elf_object_p (bfd *abfd)
 482 {
 483   bfd_default_set_arch_mach (abfd, bfd_arch_mt, elf32_mt_machine (abfd));
 484
 485   return true;
 486 }
 487
 488 /* Function to set the ELF flag bits.  */
 489
 490 static bool
 491 mt_elf_set_private_flags (bfd *abfd, flagword flags)
 492 {
 493   elf_elfheader (abfd)->e_flags = flags;
 494   elf_flags_init (abfd) = true;
 495   return true;
 496 }
 497
 498 /* Merge backend specific data from an object file to the output
 499    object file when linking.  */
 500
 501 static bool
 502 mt_elf_merge_private_bfd_data (bfd *ibfd, struct bfd_link_info *info)
 503 {
 504   bfd *obfd = info->output_bfd;
 505   flagword old_flags, new_flags;
 506   bool ok = true;
 507
 508   /* Check if we have the same endianness.  */
 509   if (!_bfd_generic_verify_endian_match (ibfd, info))
 510     return false;
 511
 512   /* If they're not both mt, then merging is meaningless, so just
 513      don't do it.  */
 514   if (strcmp (ibfd->arch_info->arch_name, "mt") != 0)
 515     return true;
 516   if (strcmp (obfd->arch_info->arch_name, "mt") != 0)
 517     return true;
 518
 519   new_flags = elf_elfheader (ibfd)->e_flags;
 520   old_flags = elf_elfheader (obfd)->e_flags;
 521
 522 #ifdef DEBUG
 523   _bfd_error_handler ("%pB: old_flags = 0x%.8x, new_flags = 0x%.8x, init = %s",
 524                       ibfd, old_flags, new_flags, elf_flags_init (obfd) ? "yes" : "no");
 525 #endif
 526
 527   if (!elf_flags_init (obfd))
 528     {
 529       old_flags = new_flags;
 530       elf_flags_init (obfd) = true;
 531     }
 532   else if ((new_flags & EF_MT_CPU_MASK) != (old_flags & EF_MT_CPU_MASK))
 533     {
 534       /* CPU has changed.  This is invalid, because MRISC, MRISC2 and
 535          MS2 are not subsets of each other.   */
 536       ok = false;
 537     }
 538
 539   if (ok)
 540     {
 541       obfd->arch_info = ibfd->arch_info;
 542       elf_elfheader (obfd)->e_flags = old_flags;
 543     }
 544
 545   return ok;
 546 }
 547
 548 static bool
 549 mt_elf_print_private_bfd_data (bfd *abfd, void *ptr)
 550 {
 551   FILE *file = (FILE *) ptr;
 552   flagword flags;
 553
 554   BFD_ASSERT (abfd != NULL && ptr != NULL);
 555
 556   /* Print normal ELF private data.  */
 557   _bfd_elf_print_private_bfd_data (abfd, ptr);
 558
 559   flags = elf_elfheader (abfd)->e_flags;
 560   fprintf (file, _("private flags = 0x%lx:"), (unsigned long) flags);
 561
 562   switch (flags & EF_MT_CPU_MASK)
 563     {
 564     default:
 565     case EF_MT_CPU_MRISC:   fprintf (file, " ms1-16-002");      break;
 566     case EF_MT_CPU_MRISC2:  fprintf (file, " ms1-16-003");      break;
 567     case EF_MT_CPU_MS2:     fprintf (file, " ms2");     break;
 568     }
 569
 570   fputc ('\n', file);
 571
 572   return true;
 573 }
 574
 575 \f
 576 #define TARGET_BIG_SYM   mt_elf32_vec
 577 #define TARGET_BIG_NAME  "elf32-mt"
 578
 579 #define ELF_ARCH         bfd_arch_mt
 580 #define ELF_MACHINE_CODE EM_MT
 581 #define ELF_MAXPAGESIZE  1 /* No pages on the MT.  */
 582
 583 #define elf_info_to_howto_rel                   NULL
 584 #define elf_info_to_howto                       mt_info_to_howto_rela
 585
 586 #define elf_backend_relocate_section            mt_elf_relocate_section
 587
 588 #define bfd_elf32_bfd_reloc_type_lookup         mt_reloc_type_lookup
 589 #define bfd_elf32_bfd_reloc_name_lookup   mt_reloc_name_lookup
 590
 591 #define elf_backend_check_relocs                mt_elf_check_relocs
 592 #define elf_backend_object_p                    mt_elf_object_p
 593 #define elf_backend_rela_normal                 1
 594
 595 #define elf_backend_can_gc_sections             1
 596
 597 #define bfd_elf32_bfd_set_private_flags         mt_elf_set_private_flags
 598 #define bfd_elf32_bfd_merge_private_bfd_data    mt_elf_merge_private_bfd_data
 599 #define bfd_elf32_bfd_print_private_bfd_data    mt_elf_print_private_bfd_data
 600
 601 #include "elf32-target.h"