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# 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} 58 59static void 60aarch64_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. */ 79static lang_input_statement_type *stub_file; 80 81/* Whether we need to call gldarm_layout_sections_again. */ 82static 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. */ 87static bfd_signed_vma group_size = 1; 88 89struct 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 97static bool 98hook_in_stub (struct hook_stub_info *info, lang_statement_union_type **lp) 99{ 100 lang_statement_union_type *l; 101 bool 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${ELFSIZE}_aarch64_size_stubs. */ 165 166/* Create a new stub section, and arrange for it to be linked 167 immediately after INPUT_SECTION. */ 168 169static asection * 170elf${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, 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${ELFSIZE}_aarch64_size_stubs. */ 209 210static void 211gldaarch64_layout_sections_again (void) 212{ 213 /* If we have changed sizes of the stub sections, then we need 214 to recalculate all the section offsets. This may mean we need to 215 add even more stubs. */ 216 ldelf_map_segments (true); 217 need_laying_out = -1; 218} 219 220static void 221build_section_lists (lang_statement_union_type *statement) 222{ 223 if (statement->header.type == lang_input_section_enum) 224 { 225 asection *i = statement->input_section.section; 226 227 if (!bfd_input_just_syms (i->owner) 228 && (i->flags & SEC_EXCLUDE) == 0 229 && i->output_section != NULL 230 && i->output_section->owner == link_info.output_bfd) 231 elf${ELFSIZE}_aarch64_next_input_section (& link_info, i); 232 } 233} 234 235static void 236gld${EMULATION_NAME}_after_allocation (void) 237{ 238 int ret; 239 240 /* bfd_elf32_discard_info just plays with debugging sections, 241 ie. doesn't affect any code, so we can delay resizing the 242 sections. It's likely we'll resize everything in the process of 243 adding stubs. */ 244 ret = bfd_elf_discard_info (link_info.output_bfd, & link_info); 245 if (ret < 0) 246 { 247 einfo (_("%X%P: .eh_frame/.stab edit: %E\n")); 248 return; 249 } 250 else if (ret > 0) 251 need_laying_out = 1; 252 253 /* If generating a relocatable output file, then we don't 254 have to examine the relocs. */ 255 if (stub_file != NULL && !bfd_link_relocatable (&link_info)) 256 { 257 ret = elf${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 288static void 289gld${EMULATION_NAME}_finish (void) 290{ 291 if (!bfd_link_relocatable (&link_info)) 292 { 293 /* Now build the linker stubs. */ 294 if (stub_file->the_bfd->sections != NULL) 295 { 296 if (! elf${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. */ 306static void 307aarch64_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 349EOF 350 351# Define some shell vars to insert bits of code into the standard elf 352# parse_args and list_options functions. 353# 354PARSE_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 364PARSE_AND_LIST_SHORTOPTS=p 365 366PARSE_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 377PARSE_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 409PARSE_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' 418PARSE_AND_LIST_ARGS_CASE_Z="$PARSE_AND_LIST_ARGS_CASE_Z $PARSE_AND_LIST_ARGS_CASE_Z_AARCH64" 419 420PARSE_AND_LIST_ARGS_CASES=' 421 case '\'p\'': 422 /* Only here for backwards compatibility. */ 423 break; 424 425 case OPTION_NO_ENUM_SIZE_WARNING: 426 no_enum_size_warning = 1; 427 break; 428 429 case OPTION_NO_WCHAR_SIZE_WARNING: 430 no_wchar_size_warning = 1; 431 break; 432 433 case OPTION_PIC_VENEER: 434 pic_veneer = 1; 435 break; 436 437 case OPTION_FIX_ERRATUM_835769: 438 fix_erratum_835769 = 1; 439 break; 440 441 case OPTION_FIX_ERRATUM_843419: 442 fix_erratum_843419 = ERRAT_ADR | ERRAT_ADRP; 443 if (optarg && *optarg) 444 { 445 if (strcmp ("full", optarg) == 0) 446 fix_erratum_843419 = ERRAT_ADR | ERRAT_ADRP; 447 else if (strcmp ("adrp", optarg) == 0) 448 fix_erratum_843419 = ERRAT_ADRP; 449 else if (strcmp ("adr", optarg) == 0) 450 fix_erratum_843419 = ERRAT_ADR; 451 else 452 einfo (_("%P: error: unrecognized option for " 453 "--fix-cortex-a53-843419: %s\n"), optarg); 454 } 455 break; 456 457 case OPTION_NO_APPLY_DYNAMIC_RELOCS: 458 no_apply_dynamic_relocs = 1; 459 break; 460 461 case OPTION_STUBGROUP_SIZE: 462 { 463 const char *end; 464 465 group_size = bfd_scan_vma (optarg, &end, 0); 466 if (*end) 467 einfo (_("%F%P: invalid number `%s'\''\n"), optarg); 468 } 469 break; 470' 471 472# We have our own before_allocation etc. functions, but they call 473# the standard routines, so give them a different name. 474LDEMUL_BEFORE_ALLOCATION=aarch64_elf_before_allocation 475LDEMUL_AFTER_ALLOCATION=gld${EMULATION_NAME}_after_allocation 476LDEMUL_CREATE_OUTPUT_SECTION_STATEMENTS=aarch64_elf_create_output_section_statements 477 478# Replace the elf before_parse function with our own. 479LDEMUL_BEFORE_PARSE=gld"${EMULATION_NAME}"_before_parse 480 481# Call the extra arm-elf function 482LDEMUL_FINISH=gld${EMULATION_NAME}_finish 483