1# This shell script emits a C file. -*- C -*- 2# Copyright (C) 2009-2020 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# 25fragment <<EOF 26 27#include "ldctor.h" 28#include "elf/aarch64.h" 29#include "elfxx-aarch64.h" 30 31static int no_enum_size_warning = 0; 32static int no_wchar_size_warning = 0; 33static int pic_veneer = 0; 34static int fix_erratum_835769 = 0; 35static erratum_84319_opts fix_erratum_843419 = ERRAT_NONE; 36static int no_apply_dynamic_relocs = 0; 37static aarch64_plt_type plt_type = PLT_NORMAL; 38static aarch64_enable_bti_type bti_type = BTI_NONE; 39 40static void 41gld${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 = ${DYNAMIC_LINK-TRUE}; 47 input_flags.add_DT_NEEDED_for_dynamic = TRUE; 48 config.has_shared = `if test -n "$GENERATE_SHLIB_SCRIPT" ; then echo TRUE ; else echo FALSE ; fi`; 49 config.separate_code = `if test "x${SEPARATE_CODE}" = xyes ; then echo TRUE ; else echo FALSE ; fi`; 50 link_info.check_relocs_after_open_input = TRUE; 51 link_info.relro = DEFAULT_LD_Z_RELRO; 52} 53 54static void 55aarch64_elf_before_allocation (void) 56{ 57 /* We should be able to set the size of the interworking stub section. We 58 can't do it until later if we have dynamic sections, though. */ 59 if (! elf_hash_table (&link_info)->dynamic_sections_created) 60 { 61 /* Here we rummage through the found bfds to collect information. */ 62 LANG_FOR_EACH_INPUT_STATEMENT (is) 63 { 64 /* Initialise mapping tables for code/data. */ 65 bfd_elf${ELFSIZE}_aarch64_init_maps (is->the_bfd); 66 } 67 } 68 69 /* Call the standard elf routine. */ 70 gld${EMULATION_NAME}_before_allocation (); 71} 72 73/* Fake input file for stubs. */ 74static lang_input_statement_type *stub_file; 75 76/* Whether we need to call gldarm_layout_sections_again. */ 77static int need_laying_out = 0; 78 79/* Maximum size of a group of input sections that can be handled by 80 one stub section. A value of +/-1 indicates the bfd back-end 81 should use a suitable default size. */ 82static bfd_signed_vma group_size = 1; 83 84struct hook_stub_info 85{ 86 lang_statement_list_type add; 87 asection *input_section; 88}; 89 90/* Traverse the linker tree to find the spot where the stub goes. */ 91 92static bfd_boolean 93hook_in_stub (struct hook_stub_info *info, lang_statement_union_type **lp) 94{ 95 lang_statement_union_type *l; 96 bfd_boolean ret; 97 98 for (; (l = *lp) != NULL; lp = &l->header.next) 99 { 100 switch (l->header.type) 101 { 102 case lang_constructors_statement_enum: 103 ret = hook_in_stub (info, &constructor_list.head); 104 if (ret) 105 return ret; 106 break; 107 108 case lang_output_section_statement_enum: 109 ret = hook_in_stub (info, 110 &l->output_section_statement.children.head); 111 if (ret) 112 return ret; 113 break; 114 115 case lang_wild_statement_enum: 116 ret = hook_in_stub (info, &l->wild_statement.children.head); 117 if (ret) 118 return ret; 119 break; 120 121 case lang_group_statement_enum: 122 ret = hook_in_stub (info, &l->group_statement.children.head); 123 if (ret) 124 return ret; 125 break; 126 127 case lang_input_section_enum: 128 if (l->input_section.section == info->input_section) 129 { 130 /* We've found our section. Insert the stub immediately 131 after its associated input section. */ 132 *(info->add.tail) = l->header.next; 133 l->header.next = info->add.head; 134 return TRUE; 135 } 136 break; 137 138 case lang_data_statement_enum: 139 case lang_reloc_statement_enum: 140 case lang_object_symbols_statement_enum: 141 case lang_output_statement_enum: 142 case lang_target_statement_enum: 143 case lang_input_statement_enum: 144 case lang_assignment_statement_enum: 145 case lang_padding_statement_enum: 146 case lang_address_statement_enum: 147 case lang_fill_statement_enum: 148 break; 149 150 default: 151 FAIL (); 152 break; 153 } 154 } 155 return FALSE; 156} 157 158 159/* Call-back for elf${ELFSIZE}_aarch64_size_stubs. */ 160 161/* Create a new stub section, and arrange for it to be linked 162 immediately after INPUT_SECTION. */ 163 164static asection * 165elf${ELFSIZE}_aarch64_add_stub_section (const char *stub_sec_name, 166 asection *input_section) 167{ 168 asection *stub_sec; 169 flagword flags; 170 asection *output_section; 171 lang_output_section_statement_type *os; 172 struct hook_stub_info info; 173 174 flags = (SEC_ALLOC | SEC_LOAD | SEC_READONLY | SEC_CODE 175 | SEC_HAS_CONTENTS | SEC_RELOC | SEC_IN_MEMORY | SEC_KEEP); 176 stub_sec = bfd_make_section_anyway_with_flags (stub_file->the_bfd, 177 stub_sec_name, flags); 178 if (stub_sec == NULL) 179 goto err_ret; 180 181 /* Long branch stubs contain a 64-bit address, so the section requires 182 8 byte alignment. */ 183 bfd_set_section_alignment (stub_sec, 3); 184 185 output_section = input_section->output_section; 186 os = lang_output_section_get (output_section); 187 188 info.input_section = input_section; 189 lang_list_init (&info.add); 190 lang_add_section (&info.add, stub_sec, NULL, os); 191 192 if (info.add.head == NULL) 193 goto err_ret; 194 195 if (hook_in_stub (&info, &os->children.head)) 196 return stub_sec; 197 198 err_ret: 199 einfo (_("%X%P: can not make stub section: %E\n")); 200 return NULL; 201} 202 203/* Another call-back for elf${ELFSIZE}_aarch64_size_stubs. */ 204 205static void 206gldaarch64_layout_sections_again (void) 207{ 208 /* If we have changed sizes of the stub sections, then we need 209 to recalculate all the section offsets. This may mean we need to 210 add even more stubs. */ 211 ldelf_map_segments (TRUE); 212 need_laying_out = -1; 213} 214 215static void 216build_section_lists (lang_statement_union_type *statement) 217{ 218 if (statement->header.type == lang_input_section_enum) 219 { 220 asection *i = statement->input_section.section; 221 222 if (!bfd_input_just_syms (i->owner) 223 && (i->flags & SEC_EXCLUDE) == 0 224 && i->output_section != NULL 225 && i->output_section->owner == link_info.output_bfd) 226 elf${ELFSIZE}_aarch64_next_input_section (& link_info, i); 227 } 228} 229 230static void 231gld${EMULATION_NAME}_after_allocation (void) 232{ 233 int ret; 234 235 /* bfd_elf32_discard_info just plays with debugging sections, 236 ie. doesn't affect any code, so we can delay resizing the 237 sections. It's likely we'll resize everything in the process of 238 adding stubs. */ 239 ret = bfd_elf_discard_info (link_info.output_bfd, & link_info); 240 if (ret < 0) 241 { 242 einfo (_("%X%P: .eh_frame/.stab edit: %E\n")); 243 return; 244 } 245 else if (ret > 0) 246 need_laying_out = 1; 247 248 /* If generating a relocatable output file, then we don't 249 have to examine the relocs. */ 250 if (stub_file != NULL && !bfd_link_relocatable (&link_info)) 251 { 252 ret = elf${ELFSIZE}_aarch64_setup_section_lists (link_info.output_bfd, 253 &link_info); 254 if (ret != 0) 255 { 256 if (ret < 0) 257 { 258 einfo (_("%X%P: could not compute sections lists " 259 "for stub generation: %E\n")); 260 return; 261 } 262 263 lang_for_each_statement (build_section_lists); 264 265 /* Call into the BFD backend to do the real work. */ 266 if (! elf${ELFSIZE}_aarch64_size_stubs (link_info.output_bfd, 267 stub_file->the_bfd, 268 & link_info, 269 group_size, 270 & elf${ELFSIZE}_aarch64_add_stub_section, 271 & gldaarch64_layout_sections_again)) 272 { 273 einfo (_("%X%P: can not size stub section: %E\n")); 274 return; 275 } 276 } 277 } 278 279 if (need_laying_out != -1) 280 ldelf_map_segments (need_laying_out); 281} 282 283static void 284gld${EMULATION_NAME}_finish (void) 285{ 286 if (!bfd_link_relocatable (&link_info)) 287 { 288 /* Now build the linker stubs. */ 289 if (stub_file->the_bfd->sections != NULL) 290 { 291 if (! elf${ELFSIZE}_aarch64_build_stubs (& link_info)) 292 einfo (_("%X%P: can not build stubs: %E\n")); 293 } 294 } 295 296 finish_default (); 297} 298 299/* This is a convenient point to tell BFD about target specific flags. 300 After the output has been created, but before inputs are read. */ 301static void 302aarch64_elf_create_output_section_statements (void) 303{ 304 if (strstr (bfd_get_target (link_info.output_bfd), "aarch64") == NULL) 305 { 306 /* The arm backend needs special fields in the output hash structure. 307 These will only be created if the output format is an arm format, 308 hence we do not support linking and changing output formats at the 309 same time. Use a link followed by objcopy to change output formats. */ 310 einfo (_("%F%P: error: cannot change output format " 311 "whilst linking %s binaries\n"), "AArch64"); 312 return; 313 } 314 315 aarch64_bti_pac_info bp_info; 316 bp_info.plt_type = plt_type; 317 bp_info.bti_type = bti_type; 318 319 bfd_elf${ELFSIZE}_aarch64_set_options (link_info.output_bfd, &link_info, 320 no_enum_size_warning, 321 no_wchar_size_warning, 322 pic_veneer, 323 fix_erratum_835769, fix_erratum_843419, 324 no_apply_dynamic_relocs, 325 bp_info); 326 327 stub_file = lang_add_input_file ("linker stubs", 328 lang_input_file_is_fake_enum, 329 NULL); 330 stub_file->the_bfd = bfd_create ("linker stubs", link_info.output_bfd); 331 if (stub_file->the_bfd == NULL 332 || ! bfd_set_arch_mach (stub_file->the_bfd, 333 bfd_get_arch (link_info.output_bfd), 334 bfd_get_mach (link_info.output_bfd))) 335 { 336 einfo (_("%F%P: can not create BFD: %E\n")); 337 return; 338 } 339 340 stub_file->the_bfd->flags |= BFD_LINKER_CREATED; 341 ldlang_add_file (stub_file); 342} 343 344EOF 345 346# Define some shell vars to insert bits of code into the standard elf 347# parse_args and list_options functions. 348# 349PARSE_AND_LIST_PROLOGUE=' 350#define OPTION_NO_ENUM_SIZE_WARNING 309 351#define OPTION_PIC_VENEER 310 352#define OPTION_STUBGROUP_SIZE 311 353#define OPTION_NO_WCHAR_SIZE_WARNING 312 354#define OPTION_FIX_ERRATUM_835769 313 355#define OPTION_FIX_ERRATUM_843419 314 356#define OPTION_NO_APPLY_DYNAMIC_RELOCS 315 357' 358 359PARSE_AND_LIST_SHORTOPTS=p 360 361PARSE_AND_LIST_LONGOPTS=' 362 { "no-pipeline-knowledge", no_argument, NULL, '\'p\''}, 363 { "no-enum-size-warning", no_argument, NULL, OPTION_NO_ENUM_SIZE_WARNING}, 364 { "pic-veneer", no_argument, NULL, OPTION_PIC_VENEER}, 365 { "stub-group-size", required_argument, NULL, OPTION_STUBGROUP_SIZE }, 366 { "no-wchar-size-warning", no_argument, NULL, OPTION_NO_WCHAR_SIZE_WARNING}, 367 { "fix-cortex-a53-835769", no_argument, NULL, OPTION_FIX_ERRATUM_835769}, 368 { "fix-cortex-a53-843419", optional_argument, NULL, OPTION_FIX_ERRATUM_843419}, 369 { "no-apply-dynamic-relocs", no_argument, NULL, OPTION_NO_APPLY_DYNAMIC_RELOCS}, 370' 371 372PARSE_AND_LIST_OPTIONS=' 373 fprintf (file, _(" --no-enum-size-warning Don'\''t warn about objects with incompatible\n" 374 " enum sizes\n")); 375 fprintf (file, _(" --no-wchar-size-warning Don'\''t warn about objects with incompatible\n" 376 " wchar_t sizes\n")); 377 fprintf (file, _(" --pic-veneer Always generate PIC interworking veneers\n")); 378 fprintf (file, _("\ 379 --stub-group-size=N Maximum size of a group of input sections that\n\ 380 can be handled by one stub section. A negative\n\ 381 value locates all stubs after their branches\n\ 382 (with a group size of -N), while a positive\n\ 383 value allows two groups of input sections, one\n\ 384 before, and one after each stub section.\n\ 385 Values of +/-1 indicate the linker should\n\ 386 choose suitable defaults.\n")); 387 fprintf (file, _(" --fix-cortex-a53-835769 Fix erratum 835769\n")); 388 fprintf (file, _("\ 389 --fix-cortex-a53-843419[=full|adr|adrp] Fix erratum 843419 and optionally specify which workaround to use.\n\ 390 full (default): Use both ADRP and ADR workaround, this will \n\ 391 increase the size of your binaries.\n\ 392 adr: Only use the ADR workaround, this will not cause any increase\n\ 393 in binary size but linking will fail if the referenced address is\n\ 394 out of range of an ADR instruction. This will remove the need of using\n\ 395 a veneer and results in both performance and size benefits.\n\ 396 adrp: Use only the ADRP workaround, this will never rewrite your ADRP\n\ 397 instruction into an ADR. As such the workaround will always use a\n\ 398 veneer and this will give you both a performance and size overhead.\n")); 399 fprintf (file, _(" --no-apply-dynamic-relocs Do not apply link-time values for dynamic relocations\n")); 400 fprintf (file, _(" -z force-bti Turn on Branch Target Identification mechanism and generate PLTs with BTI. Generate warnings for missing BTI on inputs\n")); 401 fprintf (file, _(" -z pac-plt Protect PLTs with Pointer Authentication.\n")); 402' 403 404PARSE_AND_LIST_ARGS_CASE_Z_AARCH64=' 405 else if (strcmp (optarg, "force-bti") == 0) 406 { 407 plt_type |= PLT_BTI; 408 bti_type = BTI_WARN; 409 } 410 else if (strcmp (optarg, "pac-plt") == 0) 411 plt_type |= PLT_PAC; 412' 413PARSE_AND_LIST_ARGS_CASE_Z="$PARSE_AND_LIST_ARGS_CASE_Z $PARSE_AND_LIST_ARGS_CASE_Z_AARCH64" 414 415PARSE_AND_LIST_ARGS_CASES=' 416 case '\'p\'': 417 /* Only here for backwards compatibility. */ 418 break; 419 420 case OPTION_NO_ENUM_SIZE_WARNING: 421 no_enum_size_warning = 1; 422 break; 423 424 case OPTION_NO_WCHAR_SIZE_WARNING: 425 no_wchar_size_warning = 1; 426 break; 427 428 case OPTION_PIC_VENEER: 429 pic_veneer = 1; 430 break; 431 432 case OPTION_FIX_ERRATUM_835769: 433 fix_erratum_835769 = 1; 434 break; 435 436 case OPTION_FIX_ERRATUM_843419: 437 fix_erratum_843419 = ERRAT_ADR | ERRAT_ADRP; 438 if (optarg && *optarg) 439 { 440 if (strcmp ("full", optarg) == 0) 441 fix_erratum_843419 = ERRAT_ADR | ERRAT_ADRP; 442 else if (strcmp ("adrp", optarg) == 0) 443 fix_erratum_843419 = ERRAT_ADRP; 444 else if (strcmp ("adr", optarg) == 0) 445 fix_erratum_843419 = ERRAT_ADR; 446 else 447 einfo (_("%P: error: unrecognized option for " 448 "--fix-cortex-a53-843419: %s\n"), optarg); 449 } 450 break; 451 452 case OPTION_NO_APPLY_DYNAMIC_RELOCS: 453 no_apply_dynamic_relocs = 1; 454 break; 455 456 case OPTION_STUBGROUP_SIZE: 457 { 458 const char *end; 459 460 group_size = bfd_scan_vma (optarg, &end, 0); 461 if (*end) 462 einfo (_("%F%P: invalid number `%s'\''\n"), optarg); 463 } 464 break; 465' 466 467# We have our own before_allocation etc. functions, but they call 468# the standard routines, so give them a different name. 469LDEMUL_BEFORE_ALLOCATION=aarch64_elf_before_allocation 470LDEMUL_AFTER_ALLOCATION=gld${EMULATION_NAME}_after_allocation 471LDEMUL_CREATE_OUTPUT_SECTION_STATEMENTS=aarch64_elf_create_output_section_statements 472 473# Replace the elf before_parse function with our own. 474LDEMUL_BEFORE_PARSE=gld"${EMULATION_NAME}"_before_parse 475 476# Call the extra arm-elf function 477LDEMUL_FINISH=gld${EMULATION_NAME}_finish 478