ld/emultempl/aarch64elf.em

   1 # This shell script emits a C file. -*- C -*-
   2 #   Copyright (C) 2009-2021 Free Software Foundation, Inc.
   3 #   Contributed by ARM Ltd.
   4 #
   5 # This file is part of the GNU Binutils.
   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 3 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; see the file COPYING3. If not,
  19 # see <http://www.gnu.org/licenses/>.
  20 #
  21
  22 # This file is sourced from elf.em, and defines extra aarch64-elf
  23 # specific routines.
  24 #
  25 fragment <<EOF
  26
  27 #include "ldctor.h"
  28 #include "elf/aarch64.h"
  29 #include "elfxx-aarch64.h"
  30
  31 static int no_enum_size_warning = 0;
  32 static int no_wchar_size_warning = 0;
  33 static int pic_veneer = 0;
  34 static int fix_erratum_835769 = 0;
  35 static erratum_84319_opts fix_erratum_843419 = ERRAT_NONE;
  36 static int no_apply_dynamic_relocs = 0;
  37 static aarch64_plt_type plt_type = PLT_NORMAL;
  38 static aarch64_enable_bti_type bti_type = BTI_NONE;
  39
  40 static void
  41 gld${EMULATION_NAME}_before_parse (void)
  42 {
  43 #ifndef TARGET_                 /* I.e., if not generic.  */
  44   ldfile_set_output_arch ("`echo ${ARCH}`", bfd_arch_unknown);
  45 #endif /* not TARGET_ */
  46   input_flags.dynamic = ${DYNAMIC_LINK-TRUE};
  47   config.has_shared = `if test -n "$GENERATE_SHLIB_SCRIPT" ; then echo TRUE ; else echo FALSE ; fi`;
  48   config.separate_code = `if test "x${SEPARATE_CODE}" = xyes ; then echo TRUE ; else echo FALSE ; fi`;
  49   link_info.check_relocs_after_open_input = TRUE;
  50 EOF
  51 if test -n "$COMMONPAGESIZE"; then
  52 fragment <<EOF
  53   link_info.relro = DEFAULT_LD_Z_RELRO;
  54 EOF
  55 fi
  56 fragment <<EOF
  57 }
  58
  59 static void
  60 aarch64_elf_before_allocation (void)
  61 {
  62   /* We should be able to set the size of the interworking stub section.  We
  63      can't do it until later if we have dynamic sections, though.  */
  64   if (! elf_hash_table (&link_info)->dynamic_sections_created)
  65     {
  66       /* Here we rummage through the found bfds to collect information.  */
  67       LANG_FOR_EACH_INPUT_STATEMENT (is)
  68       {
  69         /* Initialise mapping tables for code/data.  */
  70         bfd_elf${ELFSIZE}_aarch64_init_maps (is->the_bfd);
  71       }
  72     }
  73
  74   /* Call the standard elf routine.  */
  75   gld${EMULATION_NAME}_before_allocation ();
  76 }
  77
  78 /* Fake input file for stubs.  */
  79 static lang_input_statement_type *stub_file;
  80
  81 /* Whether we need to call gldarm_layout_sections_again.  */
  82 static int need_laying_out = 0;
  83
  84 /* Maximum size of a group of input sections that can be handled by
  85    one stub section.  A value of +/-1 indicates the bfd back-end
  86    should use a suitable default size.  */
  87 static bfd_signed_vma group_size = 1;
  88
  89 struct hook_stub_info
  90 {
  91   lang_statement_list_type add;
  92   asection *input_section;
  93 };
  94
  95 /* Traverse the linker tree to find the spot where the stub goes.  */
  96
  97 static bfd_boolean
  98 hook_in_stub (struct hook_stub_info *info, lang_statement_union_type **lp)
  99 {
 100   lang_statement_union_type *l;
 101   bfd_boolean ret;
 102
 103   for (; (l = *lp) != NULL; lp = &l->header.next)
 104     {
 105       switch (l->header.type)
 106         {
 107         case lang_constructors_statement_enum:
 108           ret = hook_in_stub (info, &constructor_list.head);
 109           if (ret)
 110             return ret;
 111           break;
 112
 113         case lang_output_section_statement_enum:
 114           ret = hook_in_stub (info,
 115                               &l->output_section_statement.children.head);
 116           if (ret)
 117             return ret;
 118           break;
 119
 120         case lang_wild_statement_enum:
 121           ret = hook_in_stub (info, &l->wild_statement.children.head);
 122           if (ret)
 123             return ret;
 124           break;
 125
 126         case lang_group_statement_enum:
 127           ret = hook_in_stub (info, &l->group_statement.children.head);
 128           if (ret)
 129             return ret;
 130           break;
 131
 132         case lang_input_section_enum:
 133           if (l->input_section.section == info->input_section)
 134             {
 135               /* We've found our section.  Insert the stub immediately
 136                  after its associated input section.  */
 137               *(info->add.tail) = l->header.next;
 138               l->header.next = info->add.head;
 139               return TRUE;
 140             }
 141           break;
 142
 143         case lang_data_statement_enum:
 144         case lang_reloc_statement_enum:
 145         case lang_object_symbols_statement_enum:
 146         case lang_output_statement_enum:
 147         case lang_target_statement_enum:
 148         case lang_input_statement_enum:
 149         case lang_assignment_statement_enum:
 150         case lang_padding_statement_enum:
 151         case lang_address_statement_enum:
 152         case lang_fill_statement_enum:
 153           break;
 154
 155         default:
 156           FAIL ();
 157           break;
 158         }
 159     }
 160   return FALSE;
 161 }
 162
 163
 164 /* Call-back for elf${ELFSIZE}_aarch64_size_stubs.  */
 165
 166 /* Create a new stub section, and arrange for it to be linked
 167    immediately after INPUT_SECTION.  */
 168
 169 static asection *
 170 elf${ELFSIZE}_aarch64_add_stub_section (const char *stub_sec_name,
 171                                         asection *input_section)
 172 {
 173   asection *stub_sec;
 174   flagword flags;
 175   asection *output_section;
 176   lang_output_section_statement_type *os;
 177   struct hook_stub_info info;
 178
 179   flags = (SEC_ALLOC | SEC_LOAD | SEC_READONLY | SEC_CODE
 180            | SEC_HAS_CONTENTS | SEC_RELOC | SEC_IN_MEMORY | SEC_KEEP);
 181   stub_sec = bfd_make_section_anyway_with_flags (stub_file->the_bfd,
 182                                                  stub_sec_name, flags);
 183   if (stub_sec == NULL)
 184     goto err_ret;
 185
 186   /* Long branch stubs contain a 64-bit address, so the section requires
 187      8 byte alignment.  */
 188   bfd_set_section_alignment (stub_sec, 3);
 189
 190   output_section = input_section->output_section;
 191   os = lang_output_section_get (output_section);
 192
 193   info.input_section = input_section;
 194   lang_list_init (&info.add);
 195   lang_add_section (&info.add, stub_sec, NULL, os);
 196
 197   if (info.add.head == NULL)
 198     goto err_ret;
 199
 200   if (hook_in_stub (&info, &os->children.head))
 201     return stub_sec;
 202
 203  err_ret:
 204   einfo (_("%X%P: can not make stub section: %E\n"));
 205   return NULL;
 206 }
 207
 208 /* Another call-back for elf${ELFSIZE}_aarch64_size_stubs.  */
 209
 210 static void
 211 gldaarch64_layout_sections_again (void)
 212 {
 213   /* If we have changed sizes of the stub sections, then we need
 214      to recalculate all the section offsets.  This may mean we need to
 215      add even more stubs.  */
 216   ldelf_map_segments (TRUE);
 217   need_laying_out = -1;
 218 }
 219
 220 static void
 221 build_section_lists (lang_statement_union_type *statement)
 222 {
 223   if (statement->header.type == lang_input_section_enum)
 224     {
 225       asection *i = statement->input_section.section;
 226
 227       if (!bfd_input_just_syms (i->owner)
 228           && (i->flags & SEC_EXCLUDE) == 0
 229           && i->output_section != NULL
 230           && i->output_section->owner == link_info.output_bfd)
 231         elf${ELFSIZE}_aarch64_next_input_section (& link_info, i);
 232     }
 233 }
 234
 235 static void
 236 gld${EMULATION_NAME}_after_allocation (void)
 237 {
 238   int ret;
 239
 240   /* bfd_elf32_discard_info just plays with debugging sections,
 241      ie. doesn't affect any code, so we can delay resizing the
 242      sections.  It's likely we'll resize everything in the process of
 243      adding stubs.  */
 244   ret = bfd_elf_discard_info (link_info.output_bfd, & link_info);
 245   if (ret < 0)
 246     {
 247       einfo (_("%X%P: .eh_frame/.stab edit: %E\n"));
 248       return;
 249     }
 250   else if (ret > 0)
 251     need_laying_out = 1;
 252
 253   /* If generating a relocatable output file, then we don't
 254      have to examine the relocs.  */
 255   if (stub_file != NULL && !bfd_link_relocatable (&link_info))
 256     {
 257       ret = elf${ELFSIZE}_aarch64_setup_section_lists (link_info.output_bfd,
 258                                                        &link_info);
 259       if (ret != 0)
 260         {
 261           if (ret < 0)
 262             {
 263               einfo (_("%X%P: could not compute sections lists "
 264                        "for stub generation: %E\n"));
 265               return;
 266             }
 267
 268           lang_for_each_statement (build_section_lists);
 269
 270           /* Call into the BFD backend to do the real work.  */
 271           if (! elf${ELFSIZE}_aarch64_size_stubs (link_info.output_bfd,
 272                                           stub_file->the_bfd,
 273                                           & link_info,
 274                                           group_size,
 275                                           & elf${ELFSIZE}_aarch64_add_stub_section,
 276                                           & gldaarch64_layout_sections_again))
 277             {
 278               einfo (_("%X%P: can not size stub section: %E\n"));
 279               return;
 280             }
 281         }
 282     }
 283
 284   if (need_laying_out != -1)
 285     ldelf_map_segments (need_laying_out);
 286 }
 287
 288 static void
 289 gld${EMULATION_NAME}_finish (void)
 290 {
 291   if (!bfd_link_relocatable (&link_info))
 292     {
 293       /* Now build the linker stubs.  */
 294       if (stub_file->the_bfd->sections != NULL)
 295         {
 296           if (! elf${ELFSIZE}_aarch64_build_stubs (& link_info))
 297             einfo (_("%X%P: can not build stubs: %E\n"));
 298         }
 299     }
 300
 301   finish_default ();
 302 }
 303
 304 /* This is a convenient point to tell BFD about target specific flags.
 305    After the output has been created, but before inputs are read.  */
 306 static void
 307 aarch64_elf_create_output_section_statements (void)
 308 {
 309   if (strstr (bfd_get_target (link_info.output_bfd), "aarch64") == NULL)
 310     {
 311       /* The arm backend needs special fields in the output hash structure.
 312          These will only be created if the output format is an arm format,
 313          hence we do not support linking and changing output formats at the
 314          same time.  Use a link followed by objcopy to change output formats.  */
 315       einfo (_("%F%P: error: cannot change output format "
 316                "whilst linking %s binaries\n"), "AArch64");
 317       return;
 318     }
 319
 320   aarch64_bti_pac_info bp_info;
 321   bp_info.plt_type = plt_type;
 322   bp_info.bti_type = bti_type;
 323
 324   bfd_elf${ELFSIZE}_aarch64_set_options (link_info.output_bfd, &link_info,
 325                                  no_enum_size_warning,
 326                                  no_wchar_size_warning,
 327                                  pic_veneer,
 328                                  fix_erratum_835769, fix_erratum_843419,
 329                                  no_apply_dynamic_relocs,
 330                                  bp_info);
 331
 332   stub_file = lang_add_input_file ("linker stubs",
 333                                    lang_input_file_is_fake_enum,
 334                                    NULL);
 335   stub_file->the_bfd = bfd_create ("linker stubs", link_info.output_bfd);
 336   if (stub_file->the_bfd == NULL
 337       || ! bfd_set_arch_mach (stub_file->the_bfd,
 338                               bfd_get_arch (link_info.output_bfd),
 339                               bfd_get_mach (link_info.output_bfd)))
 340     {
 341       einfo (_("%F%P: can not create BFD: %E\n"));
 342       return;
 343     }
 344
 345   stub_file->the_bfd->flags |= BFD_LINKER_CREATED;
 346   ldlang_add_file (stub_file);
 347 }
 348
 349 EOF
 350
 351 # Define some shell vars to insert bits of code into the standard elf
 352 # parse_args and list_options functions.
 353 #
 354 PARSE_AND_LIST_PROLOGUE='
 355 #define OPTION_NO_ENUM_SIZE_WARNING     309
 356 #define OPTION_PIC_VENEER               310
 357 #define OPTION_STUBGROUP_SIZE           311
 358 #define OPTION_NO_WCHAR_SIZE_WARNING    312
 359 #define OPTION_FIX_ERRATUM_835769       313
 360 #define OPTION_FIX_ERRATUM_843419       314
 361 #define OPTION_NO_APPLY_DYNAMIC_RELOCS  315
 362 '
 363
 364 PARSE_AND_LIST_SHORTOPTS=p
 365
 366 PARSE_AND_LIST_LONGOPTS='
 367   { "no-pipeline-knowledge", no_argument, NULL, '\'p\''},
 368   { "no-enum-size-warning", no_argument, NULL, OPTION_NO_ENUM_SIZE_WARNING},
 369   { "pic-veneer", no_argument, NULL, OPTION_PIC_VENEER},
 370   { "stub-group-size", required_argument, NULL, OPTION_STUBGROUP_SIZE },
 371   { "no-wchar-size-warning", no_argument, NULL, OPTION_NO_WCHAR_SIZE_WARNING},
 372   { "fix-cortex-a53-835769", no_argument, NULL, OPTION_FIX_ERRATUM_835769},
 373   { "fix-cortex-a53-843419", optional_argument, NULL, OPTION_FIX_ERRATUM_843419},
 374   { "no-apply-dynamic-relocs", no_argument, NULL, OPTION_NO_APPLY_DYNAMIC_RELOCS},
 375 '
 376
 377 PARSE_AND_LIST_OPTIONS='
 378   fprintf (file, _("  --no-enum-size-warning      Don'\''t warn about objects with incompatible\n"
 379                    "                                enum sizes\n"));
 380   fprintf (file, _("  --no-wchar-size-warning     Don'\''t warn about objects with incompatible\n"
 381                    "                                wchar_t sizes\n"));
 382   fprintf (file, _("  --pic-veneer                Always generate PIC interworking veneers\n"));
 383   fprintf (file, _("\
 384   --stub-group-size=N         Maximum size of a group of input sections that\n\
 385                                 can be handled by one stub section.  A negative\n\
 386                                 value locates all stubs after their branches\n\
 387                                 (with a group size of -N), while a positive\n\
 388                                 value allows two groups of input sections, one\n\
 389                                 before, and one after each stub section.\n\
 390                                 Values of +/-1 indicate the linker should\n\
 391                                 choose suitable defaults.\n"));
 392   fprintf (file, _("  --fix-cortex-a53-835769      Fix erratum 835769\n"));
 393   fprintf (file, _("\
 394   --fix-cortex-a53-843419[=full|adr|adrp]      Fix erratum 843419 and optionally specify which workaround to use.\n\
 395                                                full (default): Use both ADRP and ADR workaround, this will \n\
 396                                                  increase the size of your binaries.\n\
 397                                                adr: Only use the ADR workaround, this will not cause any increase\n\
 398                                                  in binary size but linking will fail if the referenced address is\n\
 399                                                  out of range of an ADR instruction.  This will remove the need of using\n\
 400                                                  a veneer and results in both performance and size benefits.\n\
 401                                                adrp: Use only the ADRP workaround, this will never rewrite your ADRP\n\
 402                                                  instruction into an ADR.  As such the workaround will always use a\n\
 403                                                  veneer and this will give you both a performance and size overhead.\n"));
 404   fprintf (file, _("  --no-apply-dynamic-relocs    Do not apply link-time values for dynamic relocations\n"));
 405   fprintf (file, _("  -z force-bti                  Turn on Branch Target Identification mechanism and generate PLTs with BTI. Generate warnings for missing BTI on inputs\n"));
 406   fprintf (file, _("  -z pac-plt                    Protect PLTs with Pointer Authentication.\n"));
 407 '
 408
 409 PARSE_AND_LIST_ARGS_CASE_Z_AARCH64='
 410       else if (strcmp (optarg, "force-bti") == 0)
 411         {
 412           plt_type |= PLT_BTI;
 413           bti_type = BTI_WARN;
 414         }
 415       else if (strcmp (optarg, "pac-plt") == 0)
 416         plt_type |= PLT_PAC;
 417 '
 418 PARSE_AND_LIST_ARGS_CASE_Z="$PARSE_AND_LIST_ARGS_CASE_Z $PARSE_AND_LIST_ARGS_CASE_Z_AARCH64"
 419
 420 PARSE_AND_LIST_ARGS_CASES='
 421     case '\'p\'':
 422       /* Only here for backwards compatibility.  */
 423       break;
 424
 425     case OPTION_NO_ENUM_SIZE_WARNING:
 426       no_enum_size_warning = 1;
 427       break;
 428
 429     case OPTION_NO_WCHAR_SIZE_WARNING:
 430       no_wchar_size_warning = 1;
 431       break;
 432
 433     case OPTION_PIC_VENEER:
 434       pic_veneer = 1;
 435       break;
 436
 437     case OPTION_FIX_ERRATUM_835769:
 438       fix_erratum_835769 = 1;
 439       break;
 440
 441     case OPTION_FIX_ERRATUM_843419:
 442       fix_erratum_843419 = ERRAT_ADR | ERRAT_ADRP;
 443       if (optarg && *optarg)
 444         {
 445           if (strcmp ("full", optarg) == 0)
 446             fix_erratum_843419 = ERRAT_ADR | ERRAT_ADRP;
 447           else if (strcmp ("adrp", optarg) == 0)
 448             fix_erratum_843419 = ERRAT_ADRP;
 449           else if (strcmp ("adr", optarg) == 0)
 450             fix_erratum_843419 = ERRAT_ADR;
 451           else
 452             einfo (_("%P: error: unrecognized option for "
 453                      "--fix-cortex-a53-843419: %s\n"), optarg);
 454         }
 455       break;
 456
 457     case OPTION_NO_APPLY_DYNAMIC_RELOCS:
 458       no_apply_dynamic_relocs = 1;
 459       break;
 460
 461     case OPTION_STUBGROUP_SIZE:
 462       {
 463         const char *end;
 464
 465         group_size = bfd_scan_vma (optarg, &end, 0);
 466         if (*end)
 467           einfo (_("%F%P: invalid number `%s'\''\n"), optarg);
 468       }
 469       break;
 470 '
 471
 472 # We have our own before_allocation etc. functions, but they call
 473 # the standard routines, so give them a different name.
 474 LDEMUL_BEFORE_ALLOCATION=aarch64_elf_before_allocation
 475 LDEMUL_AFTER_ALLOCATION=gld${EMULATION_NAME}_after_allocation
 476 LDEMUL_CREATE_OUTPUT_SECTION_STATEMENTS=aarch64_elf_create_output_section_statements
 477
 478 # Replace the elf before_parse function with our own.
 479 LDEMUL_BEFORE_PARSE=gld"${EMULATION_NAME}"_before_parse
 480
 481 # Call the extra arm-elf function
 482 LDEMUL_FINISH=gld${EMULATION_NAME}_finish