1# This shell script emits a C file. -*- C -*- 2# Copyright (C) 2009-2022 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 = ${DYNAMIC_LINK-true}; 47 config.has_shared = `if test -n "$GENERATE_SHLIB_SCRIPT" ; then echo true ; else echo false ; fi`; 48 config.separate_code = `if test "x${SEPARATE_CODE}" = xyes ; then echo true ; else echo false ; fi`; 49 link_info.check_relocs_after_open_input = true; 50EOF 51if test -n "$COMMONPAGESIZE"; then 52fragment <<EOF 53 link_info.relro = DEFAULT_LD_Z_RELRO; 54EOF 55fi 56fragment <<EOF 57 link_info.separate_code = DEFAULT_LD_Z_SEPARATE_CODE; 58 link_info.warn_execstack = DEFAULT_LD_WARN_EXECSTACK; 59 link_info.no_warn_rwx_segments = ! DEFAULT_LD_WARN_RWX_SEGMENTS; 60 link_info.default_execstack = DEFAULT_LD_EXECSTACK; 61} 62 63static void 64aarch64_elf_before_allocation (void) 65{ 66 /* We should be able to set the size of the interworking stub section. We 67 can't do it until later if we have dynamic sections, though. */ 68 if (! elf_hash_table (&link_info)->dynamic_sections_created) 69 { 70 /* Here we rummage through the found bfds to collect information. */ 71 LANG_FOR_EACH_INPUT_STATEMENT (is) 72 { 73 /* Initialise mapping tables for code/data. */ 74 bfd_elf${ELFSIZE}_aarch64_init_maps (is->the_bfd); 75 } 76 } 77 78 /* Call the standard elf routine. */ 79 gld${EMULATION_NAME}_before_allocation (); 80} 81 82/* Fake input file for stubs. */ 83static lang_input_statement_type *stub_file; 84 85/* Whether we need to call gldarm_layout_sections_again. */ 86static int need_laying_out = 0; 87 88/* Maximum size of a group of input sections that can be handled by 89 one stub section. A value of +/-1 indicates the bfd back-end 90 should use a suitable default size. */ 91static bfd_signed_vma group_size = 1; 92 93struct hook_stub_info 94{ 95 lang_statement_list_type add; 96 asection *input_section; 97}; 98 99/* Traverse the linker tree to find the spot where the stub goes. */ 100 101static bool 102hook_in_stub (struct hook_stub_info *info, lang_statement_union_type **lp) 103{ 104 lang_statement_union_type *l; 105 bool ret; 106 107 for (; (l = *lp) != NULL; lp = &l->header.next) 108 { 109 switch (l->header.type) 110 { 111 case lang_constructors_statement_enum: 112 ret = hook_in_stub (info, &constructor_list.head); 113 if (ret) 114 return ret; 115 break; 116 117 case lang_output_section_statement_enum: 118 ret = hook_in_stub (info, 119 &l->output_section_statement.children.head); 120 if (ret) 121 return ret; 122 break; 123 124 case lang_wild_statement_enum: 125 ret = hook_in_stub (info, &l->wild_statement.children.head); 126 if (ret) 127 return ret; 128 break; 129 130 case lang_group_statement_enum: 131 ret = hook_in_stub (info, &l->group_statement.children.head); 132 if (ret) 133 return ret; 134 break; 135 136 case lang_input_section_enum: 137 if (l->input_section.section == info->input_section) 138 { 139 /* We've found our section. Insert the stub immediately 140 after its associated input section. */ 141 *(info->add.tail) = l->header.next; 142 l->header.next = info->add.head; 143 return true; 144 } 145 break; 146 147 case lang_data_statement_enum: 148 case lang_reloc_statement_enum: 149 case lang_object_symbols_statement_enum: 150 case lang_output_statement_enum: 151 case lang_target_statement_enum: 152 case lang_input_statement_enum: 153 case lang_assignment_statement_enum: 154 case lang_padding_statement_enum: 155 case lang_address_statement_enum: 156 case lang_fill_statement_enum: 157 break; 158 159 default: 160 FAIL (); 161 break; 162 } 163 } 164 return false; 165} 166 167 168/* Call-back for elf${ELFSIZE}_aarch64_size_stubs. */ 169 170/* Create a new stub section, and arrange for it to be linked 171 immediately after INPUT_SECTION. */ 172 173static asection * 174elf${ELFSIZE}_aarch64_add_stub_section (const char *stub_sec_name, 175 asection *input_section) 176{ 177 asection *stub_sec; 178 flagword flags; 179 asection *output_section; 180 lang_output_section_statement_type *os; 181 struct hook_stub_info info; 182 183 flags = (SEC_ALLOC | SEC_LOAD | SEC_READONLY | SEC_CODE 184 | SEC_HAS_CONTENTS | SEC_RELOC | SEC_IN_MEMORY | SEC_KEEP); 185 stub_sec = bfd_make_section_anyway_with_flags (stub_file->the_bfd, 186 stub_sec_name, flags); 187 if (stub_sec == NULL) 188 goto err_ret; 189 190 /* Long branch stubs contain a 64-bit address, so the section requires 191 8 byte alignment. */ 192 bfd_set_section_alignment (stub_sec, 3); 193 194 output_section = input_section->output_section; 195 os = lang_output_section_get (output_section); 196 197 info.input_section = input_section; 198 lang_list_init (&info.add); 199 lang_add_section (&info.add, stub_sec, NULL, NULL, os); 200 201 if (info.add.head == NULL) 202 goto err_ret; 203 204 if (hook_in_stub (&info, &os->children.head)) 205 return stub_sec; 206 207 err_ret: 208 einfo (_("%X%P: can not make stub section: %E\n")); 209 return NULL; 210} 211 212/* Another call-back for elf${ELFSIZE}_aarch64_size_stubs. */ 213 214static void 215gldaarch64_layout_sections_again (void) 216{ 217 /* If we have changed sizes of the stub sections, then we need 218 to recalculate all the section offsets. This may mean we need to 219 add even more stubs. */ 220 ldelf_map_segments (true); 221 need_laying_out = -1; 222} 223 224static void 225build_section_lists (lang_statement_union_type *statement) 226{ 227 if (statement->header.type == lang_input_section_enum) 228 { 229 asection *i = statement->input_section.section; 230 231 if (!bfd_input_just_syms (i->owner) 232 && (i->flags & SEC_EXCLUDE) == 0 233 && i->output_section != NULL 234 && i->output_section->owner == link_info.output_bfd) 235 elf${ELFSIZE}_aarch64_next_input_section (& link_info, i); 236 } 237} 238 239static void 240gld${EMULATION_NAME}_after_allocation (void) 241{ 242 int ret; 243 244 /* bfd_elf32_discard_info just plays with debugging sections, 245 ie. doesn't affect any code, so we can delay resizing the 246 sections. It's likely we'll resize everything in the process of 247 adding stubs. */ 248 ret = bfd_elf_discard_info (link_info.output_bfd, & link_info); 249 if (ret < 0) 250 { 251 einfo (_("%X%P: .eh_frame/.stab edit: %E\n")); 252 return; 253 } 254 else if (ret > 0) 255 need_laying_out = 1; 256 257 /* If generating a relocatable output file, then we don't 258 have to examine the relocs. */ 259 if (stub_file != NULL && !bfd_link_relocatable (&link_info)) 260 { 261 ret = elf${ELFSIZE}_aarch64_setup_section_lists (link_info.output_bfd, 262 &link_info); 263 if (ret != 0) 264 { 265 if (ret < 0) 266 { 267 einfo (_("%X%P: could not compute sections lists " 268 "for stub generation: %E\n")); 269 return; 270 } 271 272 lang_for_each_statement (build_section_lists); 273 274 /* Call into the BFD backend to do the real work. */ 275 if (! elf${ELFSIZE}_aarch64_size_stubs (link_info.output_bfd, 276 stub_file->the_bfd, 277 & link_info, 278 group_size, 279 & elf${ELFSIZE}_aarch64_add_stub_section, 280 & gldaarch64_layout_sections_again)) 281 { 282 einfo (_("%X%P: can not size stub section: %E\n")); 283 return; 284 } 285 } 286 } 287 288 if (need_laying_out != -1) 289 ldelf_map_segments (need_laying_out); 290} 291 292static void 293gld${EMULATION_NAME}_finish (void) 294{ 295 if (!bfd_link_relocatable (&link_info)) 296 { 297 /* Now build the linker stubs. */ 298 if (stub_file->the_bfd->sections != NULL) 299 { 300 if (! elf${ELFSIZE}_aarch64_build_stubs (& link_info)) 301 einfo (_("%X%P: can not build stubs: %E\n")); 302 } 303 } 304 305 finish_default (); 306} 307 308/* This is a convenient point to tell BFD about target specific flags. 309 After the output has been created, but before inputs are read. */ 310static void 311aarch64_elf_create_output_section_statements (void) 312{ 313 if (strstr (bfd_get_target (link_info.output_bfd), "aarch64") == NULL) 314 { 315 /* The arm backend needs special fields in the output hash structure. 316 These will only be created if the output format is an arm format, 317 hence we do not support linking and changing output formats at the 318 same time. Use a link followed by objcopy to change output formats. */ 319 einfo (_("%F%P: error: cannot change output format " 320 "whilst linking %s binaries\n"), "AArch64"); 321 return; 322 } 323 324 aarch64_bti_pac_info bp_info; 325 bp_info.plt_type = plt_type; 326 bp_info.bti_type = bti_type; 327 328 bfd_elf${ELFSIZE}_aarch64_set_options (link_info.output_bfd, &link_info, 329 no_enum_size_warning, 330 no_wchar_size_warning, 331 pic_veneer, 332 fix_erratum_835769, fix_erratum_843419, 333 no_apply_dynamic_relocs, 334 bp_info); 335 336 stub_file = lang_add_input_file ("linker stubs", 337 lang_input_file_is_fake_enum, 338 NULL); 339 stub_file->the_bfd = bfd_create ("linker stubs", link_info.output_bfd); 340 if (stub_file->the_bfd == NULL 341 || ! bfd_set_arch_mach (stub_file->the_bfd, 342 bfd_get_arch (link_info.output_bfd), 343 bfd_get_mach (link_info.output_bfd))) 344 { 345 einfo (_("%F%P: can not create BFD: %E\n")); 346 return; 347 } 348 349 stub_file->the_bfd->flags |= BFD_LINKER_CREATED; 350 ldlang_add_file (stub_file); 351} 352 353EOF 354 355# Define some shell vars to insert bits of code into the standard elf 356# parse_args and list_options functions. 357# 358PARSE_AND_LIST_PROLOGUE=' 359#define OPTION_NO_ENUM_SIZE_WARNING 309 360#define OPTION_PIC_VENEER 310 361#define OPTION_STUBGROUP_SIZE 311 362#define OPTION_NO_WCHAR_SIZE_WARNING 312 363#define OPTION_FIX_ERRATUM_835769 313 364#define OPTION_FIX_ERRATUM_843419 314 365#define OPTION_NO_APPLY_DYNAMIC_RELOCS 315 366' 367 368PARSE_AND_LIST_SHORTOPTS=p 369 370PARSE_AND_LIST_LONGOPTS=' 371 { "no-pipeline-knowledge", no_argument, NULL, '\'p\''}, 372 { "no-enum-size-warning", no_argument, NULL, OPTION_NO_ENUM_SIZE_WARNING}, 373 { "pic-veneer", no_argument, NULL, OPTION_PIC_VENEER}, 374 { "stub-group-size", required_argument, NULL, OPTION_STUBGROUP_SIZE }, 375 { "no-wchar-size-warning", no_argument, NULL, OPTION_NO_WCHAR_SIZE_WARNING}, 376 { "fix-cortex-a53-835769", no_argument, NULL, OPTION_FIX_ERRATUM_835769}, 377 { "fix-cortex-a53-843419", optional_argument, NULL, OPTION_FIX_ERRATUM_843419}, 378 { "no-apply-dynamic-relocs", no_argument, NULL, OPTION_NO_APPLY_DYNAMIC_RELOCS}, 379' 380 381PARSE_AND_LIST_OPTIONS=' 382 fprintf (file, _(" --no-enum-size-warning Don'\''t warn about objects with incompatible\n" 383 " enum sizes\n")); 384 fprintf (file, _(" --no-wchar-size-warning Don'\''t warn about objects with incompatible\n" 385 " wchar_t sizes\n")); 386 fprintf (file, _(" --pic-veneer Always generate PIC interworking veneers\n")); 387 fprintf (file, _("\ 388 --stub-group-size=N Maximum size of a group of input sections that\n\ 389 can be handled by one stub section. A negative\n\ 390 value locates all stubs after their branches\n\ 391 (with a group size of -N), while a positive\n\ 392 value allows two groups of input sections, one\n\ 393 before, and one after each stub section.\n\ 394 Values of +/-1 indicate the linker should\n\ 395 choose suitable defaults.\n")); 396 fprintf (file, _(" --fix-cortex-a53-835769 Fix erratum 835769\n")); 397 fprintf (file, _("\ 398 --fix-cortex-a53-843419[=full|adr|adrp] Fix erratum 843419 and optionally specify which workaround to use.\n\ 399 full (default): Use both ADRP and ADR workaround, this will \n\ 400 increase the size of your binaries.\n\ 401 adr: Only use the ADR workaround, this will not cause any increase\n\ 402 in binary size but linking will fail if the referenced address is\n\ 403 out of range of an ADR instruction. This will remove the need of using\n\ 404 a veneer and results in both performance and size benefits.\n\ 405 adrp: Use only the ADRP workaround, this will never rewrite your ADRP\n\ 406 instruction into an ADR. As such the workaround will always use a\n\ 407 veneer and this will give you both a performance and size overhead.\n")); 408 fprintf (file, _(" --no-apply-dynamic-relocs Do not apply link-time values for dynamic relocations\n")); 409 fprintf (file, _(" -z force-bti Turn on Branch Target Identification mechanism and generate PLTs with BTI. Generate warnings for missing BTI on inputs\n")); 410 fprintf (file, _(" -z pac-plt Protect PLTs with Pointer Authentication.\n")); 411' 412 413PARSE_AND_LIST_ARGS_CASE_Z_AARCH64=' 414 else if (strcmp (optarg, "force-bti") == 0) 415 { 416 plt_type |= PLT_BTI; 417 bti_type = BTI_WARN; 418 } 419 else if (strcmp (optarg, "pac-plt") == 0) 420 plt_type |= PLT_PAC; 421' 422PARSE_AND_LIST_ARGS_CASE_Z="$PARSE_AND_LIST_ARGS_CASE_Z $PARSE_AND_LIST_ARGS_CASE_Z_AARCH64" 423 424PARSE_AND_LIST_ARGS_CASES=' 425 case '\'p\'': 426 /* Only here for backwards compatibility. */ 427 break; 428 429 case OPTION_NO_ENUM_SIZE_WARNING: 430 no_enum_size_warning = 1; 431 break; 432 433 case OPTION_NO_WCHAR_SIZE_WARNING: 434 no_wchar_size_warning = 1; 435 break; 436 437 case OPTION_PIC_VENEER: 438 pic_veneer = 1; 439 break; 440 441 case OPTION_FIX_ERRATUM_835769: 442 fix_erratum_835769 = 1; 443 break; 444 445 case OPTION_FIX_ERRATUM_843419: 446 fix_erratum_843419 = ERRAT_ADR | ERRAT_ADRP; 447 if (optarg && *optarg) 448 { 449 if (strcmp ("full", optarg) == 0) 450 fix_erratum_843419 = ERRAT_ADR | ERRAT_ADRP; 451 else if (strcmp ("adrp", optarg) == 0) 452 fix_erratum_843419 = ERRAT_ADRP; 453 else if (strcmp ("adr", optarg) == 0) 454 fix_erratum_843419 = ERRAT_ADR; 455 else 456 einfo (_("%P: error: unrecognized option for " 457 "--fix-cortex-a53-843419: %s\n"), optarg); 458 } 459 break; 460 461 case OPTION_NO_APPLY_DYNAMIC_RELOCS: 462 no_apply_dynamic_relocs = 1; 463 break; 464 465 case OPTION_STUBGROUP_SIZE: 466 { 467 const char *end; 468 469 group_size = bfd_scan_vma (optarg, &end, 0); 470 if (*end) 471 einfo (_("%F%P: invalid number `%s'\''\n"), optarg); 472 } 473 break; 474' 475 476# We have our own before_allocation etc. functions, but they call 477# the standard routines, so give them a different name. 478LDEMUL_BEFORE_ALLOCATION=aarch64_elf_before_allocation 479LDEMUL_AFTER_ALLOCATION=gld${EMULATION_NAME}_after_allocation 480LDEMUL_CREATE_OUTPUT_SECTION_STATEMENTS=aarch64_elf_create_output_section_statements 481 482# Replace the elf before_parse function with our own. 483LDEMUL_BEFORE_PARSE=gld"${EMULATION_NAME}"_before_parse 484 485# Call the extra arm-elf function 486LDEMUL_FINISH=gld${EMULATION_NAME}_finish 487