1 // x86_64.cc -- x86_64 target support for gold. 2 3 // Copyright (C) 2006-2024 Free Software Foundation, Inc. 4 // Written by Ian Lance Taylor <iant@google.com>. 5 6 // This file is part of gold. 7 8 // This program is free software; you can redistribute it and/or modify 9 // it under the terms of the GNU General Public License as published by 10 // the Free Software Foundation; either version 3 of the License, or 11 // (at your option) any later version. 12 13 // This program is distributed in the hope that it will be useful, 14 // but WITHOUT ANY WARRANTY; without even the implied warranty of 15 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 16 // GNU General Public License for more details. 17 18 // You should have received a copy of the GNU General Public License 19 // along with this program; if not, write to the Free Software 20 // Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston, 21 // MA 02110-1301, USA. 22 23 #include "gold.h" 24 25 #include <cstring> 26 27 #include "elfcpp.h" 28 #include "dwarf.h" 29 #include "parameters.h" 30 #include "reloc.h" 31 #include "x86_64.h" 32 #include "object.h" 33 #include "symtab.h" 34 #include "layout.h" 35 #include "output.h" 36 #include "copy-relocs.h" 37 #include "target.h" 38 #include "target-reloc.h" 39 #include "target-select.h" 40 #include "tls.h" 41 #include "freebsd.h" 42 #include "nacl.h" 43 #include "gc.h" 44 #include "icf.h" 45 46 namespace 47 { 48 49 using namespace gold; 50 51 // A class to handle the .got.plt section. 52 53 class Output_data_got_plt_x86_64 : public Output_section_data_build 54 { 55 public: 56 Output_data_got_plt_x86_64(Layout* layout) 57 : Output_section_data_build(8), 58 layout_(layout) 59 { } 60 61 Output_data_got_plt_x86_64(Layout* layout, off_t data_size) 62 : Output_section_data_build(data_size, 8), 63 layout_(layout) 64 { } 65 66 protected: 67 // Write out the PLT data. 68 void 69 do_write(Output_file*); 70 71 // Write to a map file. 72 void 73 do_print_to_mapfile(Mapfile* mapfile) const 74 { mapfile->print_output_data(this, "** GOT PLT"); } 75 76 private: 77 // A pointer to the Layout class, so that we can find the .dynamic 78 // section when we write out the GOT PLT section. 79 Layout* layout_; 80 }; 81 82 // A class to handle the PLT data. 83 // This is an abstract base class that handles most of the linker details 84 // but does not know the actual contents of PLT entries. The derived 85 // classes below fill in those details. 86 87 template<int size> 88 class Output_data_plt_x86_64 : public Output_section_data 89 { 90 public: 91 typedef Output_data_reloc<elfcpp::SHT_RELA, true, size, false> Reloc_section; 92 93 Output_data_plt_x86_64(Layout* layout, uint64_t addralign, 94 Output_data_got<64, false>* got, 95 Output_data_got_plt_x86_64* got_plt, 96 Output_data_space* got_irelative) 97 : Output_section_data(addralign), tlsdesc_rel_(NULL), 98 irelative_rel_(NULL), got_(got), got_plt_(got_plt), 99 got_irelative_(got_irelative), count_(0), irelative_count_(0), 100 tlsdesc_got_offset_(-1U), free_list_() 101 { this->init(layout); } 102 103 Output_data_plt_x86_64(Layout* layout, uint64_t plt_entry_size, 104 Output_data_got<64, false>* got, 105 Output_data_got_plt_x86_64* got_plt, 106 Output_data_space* got_irelative, 107 unsigned int plt_count) 108 : Output_section_data((plt_count + 1) * plt_entry_size, 109 plt_entry_size, false), 110 tlsdesc_rel_(NULL), irelative_rel_(NULL), got_(got), 111 got_plt_(got_plt), got_irelative_(got_irelative), count_(plt_count), 112 irelative_count_(0), tlsdesc_got_offset_(-1U), free_list_() 113 { 114 this->init(layout); 115 116 // Initialize the free list and reserve the first entry. 117 this->free_list_.init((plt_count + 1) * plt_entry_size, false); 118 this->free_list_.remove(0, plt_entry_size); 119 } 120 121 // Initialize the PLT section. 122 void 123 init(Layout* layout); 124 125 // Add an entry to the PLT. 126 void 127 add_entry(Symbol_table*, Layout*, Symbol* gsym); 128 129 // Add an entry to the PLT for a local STT_GNU_IFUNC symbol. 130 unsigned int 131 add_local_ifunc_entry(Symbol_table* symtab, Layout*, 132 Sized_relobj_file<size, false>* relobj, 133 unsigned int local_sym_index); 134 135 // Add the relocation for a PLT entry. 136 void 137 add_relocation(Symbol_table*, Layout*, Symbol* gsym, 138 unsigned int got_offset); 139 140 // Add the reserved TLSDESC_PLT entry to the PLT. 141 void 142 reserve_tlsdesc_entry(unsigned int got_offset) 143 { this->tlsdesc_got_offset_ = got_offset; } 144 145 // Return true if a TLSDESC_PLT entry has been reserved. 146 bool 147 has_tlsdesc_entry() const 148 { return this->tlsdesc_got_offset_ != -1U; } 149 150 // Return the GOT offset for the reserved TLSDESC_PLT entry. 151 unsigned int 152 get_tlsdesc_got_offset() const 153 { return this->tlsdesc_got_offset_; } 154 155 // Return the offset of the reserved TLSDESC_PLT entry. 156 unsigned int 157 get_tlsdesc_plt_offset() const 158 { 159 return ((this->count_ + this->irelative_count_ + 1) 160 * this->get_plt_entry_size()); 161 } 162 163 // Return the .rela.plt section data. 164 Reloc_section* 165 rela_plt() 166 { return this->rel_; } 167 168 // Return where the TLSDESC relocations should go. 169 Reloc_section* 170 rela_tlsdesc(Layout*); 171 172 // Return where the IRELATIVE relocations should go in the PLT 173 // relocations. 174 Reloc_section* 175 rela_irelative(Symbol_table*, Layout*); 176 177 // Return whether we created a section for IRELATIVE relocations. 178 bool 179 has_irelative_section() const 180 { return this->irelative_rel_ != NULL; } 181 182 // Get count of regular PLT entries. 183 unsigned int 184 regular_count() const 185 { return this->count_; } 186 187 // Return the total number of PLT entries. 188 unsigned int 189 entry_count() const 190 { return this->count_ + this->irelative_count_; } 191 192 // Return the offset of the first non-reserved PLT entry. 193 unsigned int 194 first_plt_entry_offset() 195 { return this->get_plt_entry_size(); } 196 197 // Return the size of a PLT entry. 198 unsigned int 199 get_plt_entry_size() const 200 { return this->do_get_plt_entry_size(); } 201 202 // Reserve a slot in the PLT for an existing symbol in an incremental update. 203 void 204 reserve_slot(unsigned int plt_index) 205 { 206 this->free_list_.remove((plt_index + 1) * this->get_plt_entry_size(), 207 (plt_index + 2) * this->get_plt_entry_size()); 208 } 209 210 // Return the PLT address to use for a global symbol. 211 uint64_t 212 address_for_global(const Symbol* sym) 213 { return do_address_for_global(sym); } 214 215 // Return the PLT address to use for a local symbol. 216 uint64_t 217 address_for_local(const Relobj* obj, unsigned int symndx) 218 { return do_address_for_local(obj, symndx); } 219 220 // Add .eh_frame information for the PLT. 221 void 222 add_eh_frame(Layout* layout) 223 { this->do_add_eh_frame(layout); } 224 225 protected: 226 Output_data_got<64, false>* 227 got() const 228 { return this->got_; } 229 230 Output_data_got_plt_x86_64* 231 got_plt() const 232 { return this->got_plt_; } 233 234 Output_data_space* 235 got_irelative() const 236 { return this->got_irelative_; } 237 238 // Fill in the first PLT entry. 239 void 240 fill_first_plt_entry(unsigned char* pov, 241 typename elfcpp::Elf_types<size>::Elf_Addr got_address, 242 typename elfcpp::Elf_types<size>::Elf_Addr plt_address) 243 { this->do_fill_first_plt_entry(pov, got_address, plt_address); } 244 245 // Fill in a normal PLT entry. Returns the offset into the entry that 246 // should be the initial GOT slot value. 247 unsigned int 248 fill_plt_entry(unsigned char* pov, 249 typename elfcpp::Elf_types<size>::Elf_Addr got_address, 250 typename elfcpp::Elf_types<size>::Elf_Addr plt_address, 251 unsigned int got_offset, 252 unsigned int plt_offset, 253 unsigned int plt_index) 254 { 255 return this->do_fill_plt_entry(pov, got_address, plt_address, 256 got_offset, plt_offset, plt_index); 257 } 258 259 // Fill in the reserved TLSDESC PLT entry. 260 void 261 fill_tlsdesc_entry(unsigned char* pov, 262 typename elfcpp::Elf_types<size>::Elf_Addr got_address, 263 typename elfcpp::Elf_types<size>::Elf_Addr plt_address, 264 typename elfcpp::Elf_types<size>::Elf_Addr got_base, 265 unsigned int tlsdesc_got_offset, 266 unsigned int plt_offset) 267 { 268 this->do_fill_tlsdesc_entry(pov, got_address, plt_address, got_base, 269 tlsdesc_got_offset, plt_offset); 270 } 271 272 virtual unsigned int 273 do_get_plt_entry_size() const = 0; 274 275 virtual void 276 do_fill_first_plt_entry(unsigned char* pov, 277 typename elfcpp::Elf_types<size>::Elf_Addr got_addr, 278 typename elfcpp::Elf_types<size>::Elf_Addr plt_addr) 279 = 0; 280 281 virtual unsigned int 282 do_fill_plt_entry(unsigned char* pov, 283 typename elfcpp::Elf_types<size>::Elf_Addr got_address, 284 typename elfcpp::Elf_types<size>::Elf_Addr plt_address, 285 unsigned int got_offset, 286 unsigned int plt_offset, 287 unsigned int plt_index) = 0; 288 289 virtual void 290 do_fill_tlsdesc_entry(unsigned char* pov, 291 typename elfcpp::Elf_types<size>::Elf_Addr got_address, 292 typename elfcpp::Elf_types<size>::Elf_Addr plt_address, 293 typename elfcpp::Elf_types<size>::Elf_Addr got_base, 294 unsigned int tlsdesc_got_offset, 295 unsigned int plt_offset) = 0; 296 297 // Return the PLT address to use for a global symbol. 298 virtual uint64_t 299 do_address_for_global(const Symbol* sym); 300 301 // Return the PLT address to use for a local symbol. 302 virtual uint64_t 303 do_address_for_local(const Relobj* obj, unsigned int symndx); 304 305 virtual void 306 do_add_eh_frame(Layout* layout) = 0; 307 308 void 309 do_adjust_output_section(Output_section* os); 310 311 // Write to a map file. 312 void 313 do_print_to_mapfile(Mapfile* mapfile) const 314 { mapfile->print_output_data(this, _("** PLT")); } 315 316 // The CIE of the .eh_frame unwind information for the PLT. 317 static const int plt_eh_frame_cie_size = 16; 318 static const unsigned char plt_eh_frame_cie[plt_eh_frame_cie_size]; 319 320 private: 321 // Set the final size. 322 void 323 set_final_data_size(); 324 325 // Write out the PLT data. 326 void 327 do_write(Output_file*); 328 329 // The reloc section. 330 Reloc_section* rel_; 331 // The TLSDESC relocs, if necessary. These must follow the regular 332 // PLT relocs. 333 Reloc_section* tlsdesc_rel_; 334 // The IRELATIVE relocs, if necessary. These must follow the 335 // regular PLT relocations and the TLSDESC relocations. 336 Reloc_section* irelative_rel_; 337 // The .got section. 338 Output_data_got<64, false>* got_; 339 // The .got.plt section. 340 Output_data_got_plt_x86_64* got_plt_; 341 // The part of the .got.plt section used for IRELATIVE relocs. 342 Output_data_space* got_irelative_; 343 // The number of PLT entries. 344 unsigned int count_; 345 // Number of PLT entries with R_X86_64_IRELATIVE relocs. These 346 // follow the regular PLT entries. 347 unsigned int irelative_count_; 348 // Offset of the reserved TLSDESC_GOT entry when needed. 349 unsigned int tlsdesc_got_offset_; 350 // List of available regions within the section, for incremental 351 // update links. 352 Free_list free_list_; 353 }; 354 355 template<int size> 356 class Output_data_plt_x86_64_standard : public Output_data_plt_x86_64<size> 357 { 358 public: 359 Output_data_plt_x86_64_standard(Layout* layout, 360 Output_data_got<64, false>* got, 361 Output_data_got_plt_x86_64* got_plt, 362 Output_data_space* got_irelative) 363 : Output_data_plt_x86_64<size>(layout, plt_entry_size, 364 got, got_plt, got_irelative) 365 { } 366 367 Output_data_plt_x86_64_standard(Layout* layout, 368 Output_data_got<64, false>* got, 369 Output_data_got_plt_x86_64* got_plt, 370 Output_data_space* got_irelative, 371 unsigned int plt_count) 372 : Output_data_plt_x86_64<size>(layout, plt_entry_size, 373 got, got_plt, got_irelative, 374 plt_count) 375 { } 376 377 protected: 378 virtual unsigned int 379 do_get_plt_entry_size() const 380 { return plt_entry_size; } 381 382 virtual void 383 do_add_eh_frame(Layout* layout) 384 { 385 layout->add_eh_frame_for_plt(this, 386 this->plt_eh_frame_cie, 387 this->plt_eh_frame_cie_size, 388 plt_eh_frame_fde, 389 plt_eh_frame_fde_size); 390 } 391 392 virtual void 393 do_fill_first_plt_entry(unsigned char* pov, 394 typename elfcpp::Elf_types<size>::Elf_Addr got_addr, 395 typename elfcpp::Elf_types<size>::Elf_Addr plt_addr); 396 397 virtual unsigned int 398 do_fill_plt_entry(unsigned char* pov, 399 typename elfcpp::Elf_types<size>::Elf_Addr got_address, 400 typename elfcpp::Elf_types<size>::Elf_Addr plt_address, 401 unsigned int got_offset, 402 unsigned int plt_offset, 403 unsigned int plt_index); 404 405 virtual void 406 do_fill_tlsdesc_entry(unsigned char* pov, 407 typename elfcpp::Elf_types<size>::Elf_Addr got_address, 408 typename elfcpp::Elf_types<size>::Elf_Addr plt_address, 409 typename elfcpp::Elf_types<size>::Elf_Addr got_base, 410 unsigned int tlsdesc_got_offset, 411 unsigned int plt_offset); 412 413 private: 414 // The size of an entry in the PLT. 415 static const int plt_entry_size = 16; 416 417 // The first entry in the PLT. 418 // From the AMD64 ABI: "Unlike Intel386 ABI, this ABI uses the same 419 // procedure linkage table for both programs and shared objects." 420 static const unsigned char first_plt_entry[plt_entry_size]; 421 422 // Other entries in the PLT for an executable. 423 static const unsigned char plt_entry[plt_entry_size]; 424 425 // The reserved TLSDESC entry in the PLT for an executable. 426 static const unsigned char tlsdesc_plt_entry[plt_entry_size]; 427 428 // The .eh_frame unwind information for the PLT. 429 static const int plt_eh_frame_fde_size = 32; 430 static const unsigned char plt_eh_frame_fde[plt_eh_frame_fde_size]; 431 }; 432 433 // We use this PLT when Indirect Branch Tracking (IBT) is enabled. 434 435 template <int size> 436 class Output_data_plt_x86_64_ibt : public Output_data_plt_x86_64<size> 437 { 438 public: 439 Output_data_plt_x86_64_ibt(Layout* layout, 440 Output_data_got<64, false>* got, 441 Output_data_got_plt_x86_64* got_plt, 442 Output_data_space* got_irelative) 443 : Output_data_plt_x86_64<size>(layout, plt_entry_size, 444 got, got_plt, got_irelative), 445 aplt_offset_(0) 446 { } 447 448 Output_data_plt_x86_64_ibt(Layout* layout, 449 Output_data_got<64, false>* got, 450 Output_data_got_plt_x86_64* got_plt, 451 Output_data_space* got_irelative, 452 unsigned int plt_count) 453 : Output_data_plt_x86_64<size>(layout, plt_entry_size, 454 got, got_plt, got_irelative, 455 plt_count), 456 aplt_offset_(0) 457 { } 458 459 protected: 460 virtual unsigned int 461 do_get_plt_entry_size() const 462 { return plt_entry_size; } 463 464 // Return the PLT address to use for a global symbol. 465 uint64_t 466 do_address_for_global(const Symbol*); 467 468 // Return the PLT address to use for a local symbol. 469 uint64_t 470 do_address_for_local(const Relobj*, unsigned int symndx); 471 472 virtual void 473 do_add_eh_frame(Layout* layout) 474 { 475 layout->add_eh_frame_for_plt(this, 476 this->plt_eh_frame_cie, 477 this->plt_eh_frame_cie_size, 478 plt_eh_frame_fde, 479 plt_eh_frame_fde_size); 480 } 481 482 virtual void 483 do_fill_first_plt_entry(unsigned char* pov, 484 typename elfcpp::Elf_types<size>::Elf_Addr got_addr, 485 typename elfcpp::Elf_types<size>::Elf_Addr plt_addr); 486 487 virtual unsigned int 488 do_fill_plt_entry(unsigned char* pov, 489 typename elfcpp::Elf_types<size>::Elf_Addr got_address, 490 typename elfcpp::Elf_types<size>::Elf_Addr plt_address, 491 unsigned int got_offset, 492 unsigned int plt_offset, 493 unsigned int plt_index); 494 495 virtual void 496 do_fill_tlsdesc_entry(unsigned char* pov, 497 typename elfcpp::Elf_types<size>::Elf_Addr got_address, 498 typename elfcpp::Elf_types<size>::Elf_Addr plt_address, 499 typename elfcpp::Elf_types<size>::Elf_Addr got_base, 500 unsigned int tlsdesc_got_offset, 501 unsigned int plt_offset); 502 503 void 504 fill_aplt_entry(unsigned char* pov, 505 typename elfcpp::Elf_types<size>::Elf_Addr got_address, 506 typename elfcpp::Elf_types<size>::Elf_Addr plt_address, 507 unsigned int got_offset, 508 unsigned int plt_offset, 509 unsigned int plt_index); 510 511 private: 512 // Set the final size. 513 void 514 set_final_data_size(); 515 516 // Write out the PLT data. 517 void 518 do_write(Output_file*); 519 520 // Offset of the Additional PLT (if using -z bndplt). 521 unsigned int aplt_offset_; 522 523 // The size of an entry in the PLT. 524 static const int plt_entry_size = 16; 525 526 // The size of an entry in the additional PLT. 527 static const int aplt_entry_size = 16; 528 529 // The first entry in the PLT. 530 // From the AMD64 ABI: "Unlike Intel386 ABI, this ABI uses the same 531 // procedure linkage table for both programs and shared objects." 532 static const unsigned char first_plt_entry[plt_entry_size]; 533 534 // Other entries in the PLT for an executable. 535 static const unsigned char plt_entry[plt_entry_size]; 536 537 // Entries in the additional PLT. 538 static const unsigned char aplt_entry[aplt_entry_size]; 539 540 // The reserved TLSDESC entry in the PLT for an executable. 541 static const unsigned char tlsdesc_plt_entry[plt_entry_size]; 542 543 // The .eh_frame unwind information for the PLT. 544 static const int plt_eh_frame_fde_size = 32; 545 static const unsigned char plt_eh_frame_fde[plt_eh_frame_fde_size]; 546 }; 547 548 template<int size> 549 class Lazy_view 550 { 551 public: 552 Lazy_view(Sized_relobj_file<size, false>* object, unsigned int data_shndx) 553 : object_(object), data_shndx_(data_shndx), view_(NULL), view_size_(0) 554 { } 555 556 inline unsigned char 557 operator[](size_t offset) 558 { 559 if (this->view_ == NULL) 560 this->view_ = this->object_->section_contents(this->data_shndx_, 561 &this->view_size_, 562 true); 563 if (offset >= this->view_size_) 564 return 0; 565 return this->view_[offset]; 566 } 567 568 private: 569 Sized_relobj_file<size, false>* object_; 570 unsigned int data_shndx_; 571 const unsigned char* view_; 572 section_size_type view_size_; 573 }; 574 575 // The x86_64 target class. 576 // See the ABI at 577 // http://www.x86-64.org/documentation/abi.pdf 578 // TLS info comes from 579 // http://people.redhat.com/drepper/tls.pdf 580 // http://www.lsd.ic.unicamp.br/~oliva/writeups/TLS/RFC-TLSDESC-x86.txt 581 582 template<int size> 583 class Target_x86_64 : public Sized_target<size, false> 584 { 585 public: 586 // In the x86_64 ABI (p 68), it says "The AMD64 ABI architectures 587 // uses only Elf64_Rela relocation entries with explicit addends." 588 typedef Output_data_reloc<elfcpp::SHT_RELA, true, size, false> Reloc_section; 589 590 Target_x86_64(const Target::Target_info* info = &x86_64_info) 591 : Sized_target<size, false>(info), 592 got_(NULL), plt_(NULL), got_plt_(NULL), got_irelative_(NULL), 593 got_tlsdesc_(NULL), global_offset_table_(NULL), rela_dyn_(NULL), 594 rela_irelative_(NULL), copy_relocs_(elfcpp::R_X86_64_COPY), 595 got_mod_index_offset_(-1U), tlsdesc_reloc_info_(), 596 tls_base_symbol_defined_(false), isa_1_used_(0), isa_1_needed_(0), 597 feature_1_(0), feature_2_used_(0), feature_2_needed_(0), 598 object_isa_1_used_(0), object_feature_1_(0), 599 object_feature_2_used_(0), seen_first_object_(false) 600 { } 601 602 // Hook for a new output section. 603 void 604 do_new_output_section(Output_section*) const; 605 606 // Scan the relocations to look for symbol adjustments. 607 void 608 gc_process_relocs(Symbol_table* symtab, 609 Layout* layout, 610 Sized_relobj_file<size, false>* object, 611 unsigned int data_shndx, 612 unsigned int sh_type, 613 const unsigned char* prelocs, 614 size_t reloc_count, 615 Output_section* output_section, 616 bool needs_special_offset_handling, 617 size_t local_symbol_count, 618 const unsigned char* plocal_symbols); 619 620 // Scan the relocations to look for symbol adjustments. 621 void 622 scan_relocs(Symbol_table* symtab, 623 Layout* layout, 624 Sized_relobj_file<size, false>* object, 625 unsigned int data_shndx, 626 unsigned int sh_type, 627 const unsigned char* prelocs, 628 size_t reloc_count, 629 Output_section* output_section, 630 bool needs_special_offset_handling, 631 size_t local_symbol_count, 632 const unsigned char* plocal_symbols); 633 634 // Finalize the sections. 635 void 636 do_finalize_sections(Layout*, const Input_objects*, Symbol_table*); 637 638 // Return the value to use for a dynamic which requires special 639 // treatment. 640 uint64_t 641 do_dynsym_value(const Symbol*) const; 642 643 // Relocate a section. 644 void 645 relocate_section(const Relocate_info<size, false>*, 646 unsigned int sh_type, 647 const unsigned char* prelocs, 648 size_t reloc_count, 649 Output_section* output_section, 650 bool needs_special_offset_handling, 651 unsigned char* view, 652 typename elfcpp::Elf_types<size>::Elf_Addr view_address, 653 section_size_type view_size, 654 const Reloc_symbol_changes*); 655 656 // Scan the relocs during a relocatable link. 657 void 658 scan_relocatable_relocs(Symbol_table* symtab, 659 Layout* layout, 660 Sized_relobj_file<size, false>* object, 661 unsigned int data_shndx, 662 unsigned int sh_type, 663 const unsigned char* prelocs, 664 size_t reloc_count, 665 Output_section* output_section, 666 bool needs_special_offset_handling, 667 size_t local_symbol_count, 668 const unsigned char* plocal_symbols, 669 Relocatable_relocs*); 670 671 // Scan the relocs for --emit-relocs. 672 void 673 emit_relocs_scan(Symbol_table* symtab, 674 Layout* layout, 675 Sized_relobj_file<size, false>* object, 676 unsigned int data_shndx, 677 unsigned int sh_type, 678 const unsigned char* prelocs, 679 size_t reloc_count, 680 Output_section* output_section, 681 bool needs_special_offset_handling, 682 size_t local_symbol_count, 683 const unsigned char* plocal_syms, 684 Relocatable_relocs* rr); 685 686 // Emit relocations for a section. 687 void 688 relocate_relocs( 689 const Relocate_info<size, false>*, 690 unsigned int sh_type, 691 const unsigned char* prelocs, 692 size_t reloc_count, 693 Output_section* output_section, 694 typename elfcpp::Elf_types<size>::Elf_Off offset_in_output_section, 695 unsigned char* view, 696 typename elfcpp::Elf_types<size>::Elf_Addr view_address, 697 section_size_type view_size, 698 unsigned char* reloc_view, 699 section_size_type reloc_view_size); 700 701 // Return a string used to fill a code section with nops. 702 std::string 703 do_code_fill(section_size_type length) const; 704 705 // Return whether SYM is defined by the ABI. 706 bool 707 do_is_defined_by_abi(const Symbol* sym) const 708 { return strcmp(sym->name(), "__tls_get_addr") == 0; } 709 710 // Return the symbol index to use for a target specific relocation. 711 // The only target specific relocation is R_X86_64_TLSDESC for a 712 // local symbol, which is an absolute reloc. 713 unsigned int 714 do_reloc_symbol_index(void*, unsigned int r_type) const 715 { 716 gold_assert(r_type == elfcpp::R_X86_64_TLSDESC); 717 return 0; 718 } 719 720 // Return the addend to use for a target specific relocation. 721 uint64_t 722 do_reloc_addend(void* arg, unsigned int r_type, uint64_t addend) const; 723 724 // Return the PLT section. 725 uint64_t 726 do_plt_address_for_global(const Symbol* gsym) const 727 { return this->plt_section()->address_for_global(gsym); } 728 729 uint64_t 730 do_plt_address_for_local(const Relobj* relobj, unsigned int symndx) const 731 { return this->plt_section()->address_for_local(relobj, symndx); } 732 733 // This function should be defined in targets that can use relocation 734 // types to determine (implemented in local_reloc_may_be_function_pointer 735 // and global_reloc_may_be_function_pointer) 736 // if a function's pointer is taken. ICF uses this in safe mode to only 737 // fold those functions whose pointer is defintely not taken. For x86_64 738 // pie binaries, safe ICF cannot be done by looking at only relocation 739 // types, and for certain cases (e.g. R_X86_64_PC32), the instruction 740 // opcode is checked as well to distinguish a function call from taking 741 // a function's pointer. 742 bool 743 do_can_check_for_function_pointers() const 744 { return true; } 745 746 // Return the base for a DW_EH_PE_datarel encoding. 747 uint64_t 748 do_ehframe_datarel_base() const; 749 750 // Adjust -fsplit-stack code which calls non-split-stack code. 751 void 752 do_calls_non_split(Relobj* object, unsigned int shndx, 753 section_offset_type fnoffset, section_size_type fnsize, 754 const unsigned char* prelocs, size_t reloc_count, 755 unsigned char* view, section_size_type view_size, 756 std::string* from, std::string* to) const; 757 758 // Return the size of the GOT section. 759 section_size_type 760 got_size() const 761 { 762 gold_assert(this->got_ != NULL); 763 return this->got_->data_size(); 764 } 765 766 // Return the number of entries in the GOT. 767 unsigned int 768 got_entry_count() const 769 { 770 if (this->got_ == NULL) 771 return 0; 772 return this->got_size() / 8; 773 } 774 775 // Return the number of entries in the PLT. 776 unsigned int 777 plt_entry_count() const; 778 779 // Return the offset of the first non-reserved PLT entry. 780 unsigned int 781 first_plt_entry_offset() const; 782 783 // Return the size of each PLT entry. 784 unsigned int 785 plt_entry_size() const; 786 787 // Return the size of each GOT entry. 788 unsigned int 789 got_entry_size() const 790 { return 8; }; 791 792 // Create the GOT section for an incremental update. 793 Output_data_got_base* 794 init_got_plt_for_update(Symbol_table* symtab, 795 Layout* layout, 796 unsigned int got_count, 797 unsigned int plt_count); 798 799 // Reserve a GOT entry for a local symbol, and regenerate any 800 // necessary dynamic relocations. 801 void 802 reserve_local_got_entry(unsigned int got_index, 803 Sized_relobj<size, false>* obj, 804 unsigned int r_sym, 805 unsigned int got_type); 806 807 // Reserve a GOT entry for a global symbol, and regenerate any 808 // necessary dynamic relocations. 809 void 810 reserve_global_got_entry(unsigned int got_index, Symbol* gsym, 811 unsigned int got_type); 812 813 // Register an existing PLT entry for a global symbol. 814 void 815 register_global_plt_entry(Symbol_table*, Layout*, unsigned int plt_index, 816 Symbol* gsym); 817 818 // Force a COPY relocation for a given symbol. 819 void 820 emit_copy_reloc(Symbol_table*, Symbol*, Output_section*, off_t); 821 822 // Apply an incremental relocation. 823 void 824 apply_relocation(const Relocate_info<size, false>* relinfo, 825 typename elfcpp::Elf_types<size>::Elf_Addr r_offset, 826 unsigned int r_type, 827 typename elfcpp::Elf_types<size>::Elf_Swxword r_addend, 828 const Symbol* gsym, 829 unsigned char* view, 830 typename elfcpp::Elf_types<size>::Elf_Addr address, 831 section_size_type view_size); 832 833 // Add a new reloc argument, returning the index in the vector. 834 size_t 835 add_tlsdesc_info(Sized_relobj_file<size, false>* object, unsigned int r_sym) 836 { 837 this->tlsdesc_reloc_info_.push_back(Tlsdesc_info(object, r_sym)); 838 return this->tlsdesc_reloc_info_.size() - 1; 839 } 840 841 Output_data_plt_x86_64<size>* 842 make_data_plt(Layout* layout, 843 Output_data_got<64, false>* got, 844 Output_data_got_plt_x86_64* got_plt, 845 Output_data_space* got_irelative) 846 { 847 return this->do_make_data_plt(layout, got, got_plt, got_irelative); 848 } 849 850 Output_data_plt_x86_64<size>* 851 make_data_plt(Layout* layout, 852 Output_data_got<64, false>* got, 853 Output_data_got_plt_x86_64* got_plt, 854 Output_data_space* got_irelative, 855 unsigned int plt_count) 856 { 857 return this->do_make_data_plt(layout, got, got_plt, got_irelative, 858 plt_count); 859 } 860 861 virtual Output_data_plt_x86_64<size>* 862 do_make_data_plt(Layout* layout, 863 Output_data_got<64, false>* got, 864 Output_data_got_plt_x86_64* got_plt, 865 Output_data_space* got_irelative); 866 867 virtual Output_data_plt_x86_64<size>* 868 do_make_data_plt(Layout* layout, 869 Output_data_got<64, false>* got, 870 Output_data_got_plt_x86_64* got_plt, 871 Output_data_space* got_irelative, 872 unsigned int plt_count); 873 874 private: 875 // The class which scans relocations. 876 class Scan 877 { 878 public: 879 Scan() 880 : issued_non_pic_error_(false) 881 { } 882 883 static inline int 884 get_reference_flags(unsigned int r_type); 885 886 inline void 887 local(Symbol_table* symtab, Layout* layout, Target_x86_64* target, 888 Sized_relobj_file<size, false>* object, 889 unsigned int data_shndx, 890 Output_section* output_section, 891 const elfcpp::Rela<size, false>& reloc, unsigned int r_type, 892 const elfcpp::Sym<size, false>& lsym, 893 bool is_discarded); 894 895 inline void 896 global(Symbol_table* symtab, Layout* layout, Target_x86_64* target, 897 Sized_relobj_file<size, false>* object, 898 unsigned int data_shndx, 899 Output_section* output_section, 900 const elfcpp::Rela<size, false>& reloc, unsigned int r_type, 901 Symbol* gsym); 902 903 inline bool 904 local_reloc_may_be_function_pointer(Symbol_table* symtab, Layout* layout, 905 Target_x86_64* target, 906 Sized_relobj_file<size, false>* object, 907 unsigned int data_shndx, 908 Output_section* output_section, 909 const elfcpp::Rela<size, false>& reloc, 910 unsigned int r_type, 911 const elfcpp::Sym<size, false>& lsym); 912 913 inline bool 914 global_reloc_may_be_function_pointer(Symbol_table* symtab, Layout* layout, 915 Target_x86_64* target, 916 Sized_relobj_file<size, false>* object, 917 unsigned int data_shndx, 918 Output_section* output_section, 919 const elfcpp::Rela<size, false>& reloc, 920 unsigned int r_type, 921 Symbol* gsym); 922 923 private: 924 static void 925 unsupported_reloc_local(Sized_relobj_file<size, false>*, 926 unsigned int r_type); 927 928 static void 929 unsupported_reloc_global(Sized_relobj_file<size, false>*, 930 unsigned int r_type, Symbol*); 931 932 void 933 check_non_pic(Relobj*, unsigned int r_type, Symbol*); 934 935 inline bool 936 possible_function_pointer_reloc(Sized_relobj_file<size, false>* src_obj, 937 unsigned int src_indx, 938 unsigned int r_offset, 939 unsigned int r_type); 940 941 bool 942 reloc_needs_plt_for_ifunc(Sized_relobj_file<size, false>*, 943 unsigned int r_type); 944 945 // Whether we have issued an error about a non-PIC compilation. 946 bool issued_non_pic_error_; 947 }; 948 949 // The class which implements relocation. 950 class Relocate 951 { 952 public: 953 Relocate() 954 : skip_call_tls_get_addr_(false) 955 { } 956 957 ~Relocate() 958 { 959 if (this->skip_call_tls_get_addr_) 960 { 961 // FIXME: This needs to specify the location somehow. 962 gold_error(_("missing expected TLS relocation")); 963 } 964 } 965 966 // Do a relocation. Return false if the caller should not issue 967 // any warnings about this relocation. 968 inline bool 969 relocate(const Relocate_info<size, false>*, unsigned int, 970 Target_x86_64*, Output_section*, size_t, const unsigned char*, 971 const Sized_symbol<size>*, const Symbol_value<size>*, 972 unsigned char*, typename elfcpp::Elf_types<size>::Elf_Addr, 973 section_size_type); 974 975 private: 976 // Do a TLS relocation. 977 inline void 978 relocate_tls(const Relocate_info<size, false>*, Target_x86_64*, 979 size_t relnum, const elfcpp::Rela<size, false>&, 980 unsigned int r_type, const Sized_symbol<size>*, 981 const Symbol_value<size>*, 982 unsigned char*, typename elfcpp::Elf_types<size>::Elf_Addr, 983 section_size_type); 984 985 // Do a TLS General-Dynamic to Initial-Exec transition. 986 inline void 987 tls_gd_to_ie(const Relocate_info<size, false>*, size_t relnum, 988 const elfcpp::Rela<size, false>&, unsigned int r_type, 989 typename elfcpp::Elf_types<size>::Elf_Addr value, 990 unsigned char* view, 991 typename elfcpp::Elf_types<size>::Elf_Addr, 992 section_size_type view_size); 993 994 // Do a TLS General-Dynamic to Local-Exec transition. 995 inline void 996 tls_gd_to_le(const Relocate_info<size, false>*, size_t relnum, 997 Output_segment* tls_segment, 998 const elfcpp::Rela<size, false>&, unsigned int r_type, 999 typename elfcpp::Elf_types<size>::Elf_Addr value, 1000 unsigned char* view, 1001 section_size_type view_size); 1002 1003 // Do a TLSDESC-style General-Dynamic to Initial-Exec transition. 1004 inline void 1005 tls_desc_gd_to_ie(const Relocate_info<size, false>*, size_t relnum, 1006 const elfcpp::Rela<size, false>&, unsigned int r_type, 1007 typename elfcpp::Elf_types<size>::Elf_Addr value, 1008 unsigned char* view, 1009 typename elfcpp::Elf_types<size>::Elf_Addr, 1010 section_size_type view_size); 1011 1012 // Do a TLSDESC-style General-Dynamic to Local-Exec transition. 1013 inline void 1014 tls_desc_gd_to_le(const Relocate_info<size, false>*, size_t relnum, 1015 Output_segment* tls_segment, 1016 const elfcpp::Rela<size, false>&, unsigned int r_type, 1017 typename elfcpp::Elf_types<size>::Elf_Addr value, 1018 unsigned char* view, 1019 section_size_type view_size); 1020 1021 // Do a TLS Local-Dynamic to Local-Exec transition. 1022 inline void 1023 tls_ld_to_le(const Relocate_info<size, false>*, size_t relnum, 1024 Output_segment* tls_segment, 1025 const elfcpp::Rela<size, false>&, unsigned int r_type, 1026 typename elfcpp::Elf_types<size>::Elf_Addr value, 1027 unsigned char* view, 1028 section_size_type view_size); 1029 1030 // Do a TLS Initial-Exec to Local-Exec transition. 1031 static inline void 1032 tls_ie_to_le(const Relocate_info<size, false>*, size_t relnum, 1033 Output_segment* tls_segment, 1034 const elfcpp::Rela<size, false>&, unsigned int r_type, 1035 typename elfcpp::Elf_types<size>::Elf_Addr value, 1036 unsigned char* view, 1037 section_size_type view_size); 1038 1039 // This is set if we should skip the next reloc, which should be a 1040 // PLT32 reloc against ___tls_get_addr. 1041 bool skip_call_tls_get_addr_; 1042 }; 1043 1044 // Check if relocation against this symbol is a candidate for 1045 // conversion from 1046 // mov foo@GOTPCREL(%rip), %reg 1047 // to lea foo(%rip), %reg. 1048 template<class View_type> 1049 static inline bool 1050 can_convert_mov_to_lea(const Symbol* gsym, unsigned int r_type, 1051 size_t r_offset, View_type* view) 1052 { 1053 gold_assert(gsym != NULL); 1054 // We cannot do the conversion unless it's one of these relocations. 1055 if (r_type != elfcpp::R_X86_64_GOTPCREL 1056 && r_type != elfcpp::R_X86_64_GOTPCRELX 1057 && r_type != elfcpp::R_X86_64_REX_GOTPCRELX 1058 && r_type != elfcpp::R_X86_64_CODE_4_GOTPCRELX) 1059 return false; 1060 // We cannot convert references to IFUNC symbols, or to symbols that 1061 // are not local to the current module. 1062 // We can't do predefined symbols because they may become undefined 1063 // (e.g., __ehdr_start when the headers aren't mapped to a segment). 1064 if (gsym->type() == elfcpp::STT_GNU_IFUNC 1065 || gsym->is_undefined() 1066 || gsym->is_predefined() 1067 || gsym->is_from_dynobj() 1068 || gsym->is_preemptible()) 1069 return false; 1070 // If we are building a shared object and the symbol is protected, we may 1071 // need to go through the GOT. 1072 if (parameters->options().shared() 1073 && gsym->visibility() == elfcpp::STV_PROTECTED) 1074 return false; 1075 // We cannot convert references to the _DYNAMIC symbol. 1076 if (strcmp(gsym->name(), "_DYNAMIC") == 0) 1077 return false; 1078 // Check for a MOV opcode. 1079 return (*view)[r_offset - 2] == 0x8b; 1080 } 1081 1082 // Convert 1083 // callq *foo@GOTPCRELX(%rip) to 1084 // addr32 callq foo 1085 // and jmpq *foo@GOTPCRELX(%rip) to 1086 // jmpq foo 1087 // nop 1088 template<class View_type> 1089 static inline bool 1090 can_convert_callq_to_direct(const Symbol* gsym, unsigned int r_type, 1091 size_t r_offset, View_type* view) 1092 { 1093 gold_assert(gsym != NULL); 1094 // We cannot do the conversion unless it's a GOTPCRELX relocation. 1095 if (r_type != elfcpp::R_X86_64_GOTPCRELX) 1096 return false; 1097 // We cannot convert references to IFUNC symbols, or to symbols that 1098 // are not local to the current module. 1099 if (gsym->type() == elfcpp::STT_GNU_IFUNC 1100 || gsym->is_undefined () 1101 || gsym->is_from_dynobj() 1102 || gsym->is_preemptible()) 1103 return false; 1104 // Check for a CALLQ or JMPQ opcode. 1105 return ((*view)[r_offset - 2] == 0xff 1106 && ((*view)[r_offset - 1] == 0x15 1107 || (*view)[r_offset - 1] == 0x25)); 1108 } 1109 1110 // Adjust TLS relocation type based on the options and whether this 1111 // is a local symbol. 1112 static tls::Tls_optimization 1113 optimize_tls_reloc(bool is_final, int r_type, size_t r_offset, 1114 const unsigned char* reloc_view); 1115 1116 // Get the GOT section, creating it if necessary. 1117 Output_data_got<64, false>* 1118 got_section(Symbol_table*, Layout*); 1119 1120 // Get the GOT PLT section. 1121 Output_data_got_plt_x86_64* 1122 got_plt_section() const 1123 { 1124 gold_assert(this->got_plt_ != NULL); 1125 return this->got_plt_; 1126 } 1127 1128 // Get the GOT section for TLSDESC entries. 1129 Output_data_got<64, false>* 1130 got_tlsdesc_section() const 1131 { 1132 gold_assert(this->got_tlsdesc_ != NULL); 1133 return this->got_tlsdesc_; 1134 } 1135 1136 // Create the PLT section. 1137 void 1138 make_plt_section(Symbol_table* symtab, Layout* layout); 1139 1140 // Create a PLT entry for a global symbol. 1141 void 1142 make_plt_entry(Symbol_table*, Layout*, Symbol*); 1143 1144 // Create a PLT entry for a local STT_GNU_IFUNC symbol. 1145 void 1146 make_local_ifunc_plt_entry(Symbol_table*, Layout*, 1147 Sized_relobj_file<size, false>* relobj, 1148 unsigned int local_sym_index); 1149 1150 // Define the _TLS_MODULE_BASE_ symbol in the TLS segment. 1151 void 1152 define_tls_base_symbol(Symbol_table*, Layout*); 1153 1154 // Create the reserved PLT and GOT entries for the TLS descriptor resolver. 1155 void 1156 reserve_tlsdesc_entries(Symbol_table* symtab, Layout* layout); 1157 1158 // Create a GOT entry for the TLS module index. 1159 unsigned int 1160 got_mod_index_entry(Symbol_table* symtab, Layout* layout, 1161 Sized_relobj_file<size, false>* object); 1162 1163 // Get the PLT section. 1164 Output_data_plt_x86_64<size>* 1165 plt_section() const 1166 { 1167 gold_assert(this->plt_ != NULL); 1168 return this->plt_; 1169 } 1170 1171 // Get the dynamic reloc section, creating it if necessary. 1172 Reloc_section* 1173 rela_dyn_section(Layout*); 1174 1175 // Get the section to use for TLSDESC relocations. 1176 Reloc_section* 1177 rela_tlsdesc_section(Layout*) const; 1178 1179 // Get the section to use for IRELATIVE relocations. 1180 Reloc_section* 1181 rela_irelative_section(Layout*); 1182 1183 // Add a potential copy relocation. 1184 void 1185 copy_reloc(Symbol_table* symtab, Layout* layout, 1186 Sized_relobj_file<size, false>* object, 1187 unsigned int shndx, Output_section* output_section, 1188 Symbol* sym, const elfcpp::Rela<size, false>& reloc) 1189 { 1190 unsigned int r_type = elfcpp::elf_r_type<size>(reloc.get_r_info()); 1191 this->copy_relocs_.copy_reloc(symtab, layout, 1192 symtab->get_sized_symbol<size>(sym), 1193 object, shndx, output_section, 1194 r_type, reloc.get_r_offset(), 1195 reloc.get_r_addend(), 1196 this->rela_dyn_section(layout)); 1197 } 1198 1199 // Record a target-specific program property in the .note.gnu.property 1200 // section. 1201 void 1202 record_gnu_property(unsigned int, unsigned int, size_t, 1203 const unsigned char*, const Object*); 1204 1205 // Merge the target-specific program properties from the current object. 1206 void 1207 merge_gnu_properties(const Object*); 1208 1209 // Finalize the target-specific program properties and add them back to 1210 // the layout. 1211 void 1212 do_finalize_gnu_properties(Layout*) const; 1213 1214 // Information about this specific target which we pass to the 1215 // general Target structure. 1216 static const Target::Target_info x86_64_info; 1217 1218 // The types of GOT entries needed for this platform. 1219 // These values are exposed to the ABI in an incremental link. 1220 // Do not renumber existing values without changing the version 1221 // number of the .gnu_incremental_inputs section. 1222 enum Got_type 1223 { 1224 GOT_TYPE_STANDARD = 0, // GOT entry for a regular symbol 1225 GOT_TYPE_TLS_OFFSET = 1, // GOT entry for TLS offset 1226 GOT_TYPE_TLS_PAIR = 2, // GOT entry for TLS module/offset pair 1227 GOT_TYPE_TLS_DESC = 3 // GOT entry for TLS_DESC pair 1228 }; 1229 1230 // This type is used as the argument to the target specific 1231 // relocation routines. The only target specific reloc is 1232 // R_X86_64_TLSDESC against a local symbol. 1233 struct Tlsdesc_info 1234 { 1235 Tlsdesc_info(Sized_relobj_file<size, false>* a_object, unsigned int a_r_sym) 1236 : object(a_object), r_sym(a_r_sym) 1237 { } 1238 1239 // The object in which the local symbol is defined. 1240 Sized_relobj_file<size, false>* object; 1241 // The local symbol index in the object. 1242 unsigned int r_sym; 1243 }; 1244 1245 // The GOT section. 1246 Output_data_got<64, false>* got_; 1247 // The PLT section. 1248 Output_data_plt_x86_64<size>* plt_; 1249 // The GOT PLT section. 1250 Output_data_got_plt_x86_64* got_plt_; 1251 // The GOT section for IRELATIVE relocations. 1252 Output_data_space* got_irelative_; 1253 // The GOT section for TLSDESC relocations. 1254 Output_data_got<64, false>* got_tlsdesc_; 1255 // The _GLOBAL_OFFSET_TABLE_ symbol. 1256 Symbol* global_offset_table_; 1257 // The dynamic reloc section. 1258 Reloc_section* rela_dyn_; 1259 // The section to use for IRELATIVE relocs. 1260 Reloc_section* rela_irelative_; 1261 // Relocs saved to avoid a COPY reloc. 1262 Copy_relocs<elfcpp::SHT_RELA, size, false> copy_relocs_; 1263 // Offset of the GOT entry for the TLS module index. 1264 unsigned int got_mod_index_offset_; 1265 // We handle R_X86_64_TLSDESC against a local symbol as a target 1266 // specific relocation. Here we store the object and local symbol 1267 // index for the relocation. 1268 std::vector<Tlsdesc_info> tlsdesc_reloc_info_; 1269 // True if the _TLS_MODULE_BASE_ symbol has been defined. 1270 bool tls_base_symbol_defined_; 1271 // Target-specific program properties, from .note.gnu.property section. 1272 // Each bit represents a specific feature. 1273 uint32_t isa_1_used_; 1274 uint32_t isa_1_needed_; 1275 uint32_t feature_1_; 1276 uint32_t feature_2_used_; 1277 uint32_t feature_2_needed_; 1278 // Target-specific properties from the current object. 1279 // These bits get ORed into ISA_1_USED_ after all properties for the object 1280 // have been processed. But if either is all zeroes (as when the property 1281 // is absent from an object), the result should be all zeroes. 1282 // (See PR ld/23486.) 1283 uint32_t object_isa_1_used_; 1284 // These bits get ANDed into FEATURE_1_ after all properties for the object 1285 // have been processed. 1286 uint32_t object_feature_1_; 1287 uint32_t object_feature_2_used_; 1288 // Whether we have seen our first object, for use in initializing FEATURE_1_. 1289 bool seen_first_object_; 1290 }; 1291 1292 template<> 1293 const Target::Target_info Target_x86_64<64>::x86_64_info = 1294 { 1295 64, // size 1296 false, // is_big_endian 1297 elfcpp::EM_X86_64, // machine_code 1298 false, // has_make_symbol 1299 false, // has_resolve 1300 true, // has_code_fill 1301 true, // is_default_stack_executable 1302 true, // can_icf_inline_merge_sections 1303 '\0', // wrap_char 1304 "/lib/ld64.so.1", // program interpreter 1305 0x400000, // default_text_segment_address 1306 0x1000, // abi_pagesize (overridable by -z max-page-size) 1307 0x1000, // common_pagesize (overridable by -z common-page-size) 1308 false, // isolate_execinstr 1309 0, // rosegment_gap 1310 elfcpp::SHN_UNDEF, // small_common_shndx 1311 elfcpp::SHN_X86_64_LCOMMON, // large_common_shndx 1312 0, // small_common_section_flags 1313 elfcpp::SHF_X86_64_LARGE, // large_common_section_flags 1314 NULL, // attributes_section 1315 NULL, // attributes_vendor 1316 "_start", // entry_symbol_name 1317 32, // hash_entry_size 1318 elfcpp::SHT_X86_64_UNWIND, // unwind_section_type 1319 }; 1320 1321 template<> 1322 const Target::Target_info Target_x86_64<32>::x86_64_info = 1323 { 1324 32, // size 1325 false, // is_big_endian 1326 elfcpp::EM_X86_64, // machine_code 1327 false, // has_make_symbol 1328 false, // has_resolve 1329 true, // has_code_fill 1330 true, // is_default_stack_executable 1331 true, // can_icf_inline_merge_sections 1332 '\0', // wrap_char 1333 "/libx32/ldx32.so.1", // program interpreter 1334 0x400000, // default_text_segment_address 1335 0x1000, // abi_pagesize (overridable by -z max-page-size) 1336 0x1000, // common_pagesize (overridable by -z common-page-size) 1337 false, // isolate_execinstr 1338 0, // rosegment_gap 1339 elfcpp::SHN_UNDEF, // small_common_shndx 1340 elfcpp::SHN_X86_64_LCOMMON, // large_common_shndx 1341 0, // small_common_section_flags 1342 elfcpp::SHF_X86_64_LARGE, // large_common_section_flags 1343 NULL, // attributes_section 1344 NULL, // attributes_vendor 1345 "_start", // entry_symbol_name 1346 32, // hash_entry_size 1347 elfcpp::SHT_X86_64_UNWIND, // unwind_section_type 1348 }; 1349 1350 // This is called when a new output section is created. This is where 1351 // we handle the SHF_X86_64_LARGE. 1352 1353 template<int size> 1354 void 1355 Target_x86_64<size>::do_new_output_section(Output_section* os) const 1356 { 1357 if ((os->flags() & elfcpp::SHF_X86_64_LARGE) != 0) 1358 os->set_is_large_section(); 1359 } 1360 1361 // Get the GOT section, creating it if necessary. 1362 1363 template<int size> 1364 Output_data_got<64, false>* 1365 Target_x86_64<size>::got_section(Symbol_table* symtab, Layout* layout) 1366 { 1367 if (this->got_ == NULL) 1368 { 1369 gold_assert(symtab != NULL && layout != NULL); 1370 1371 // When using -z now, we can treat .got.plt as a relro section. 1372 // Without -z now, it is modified after program startup by lazy 1373 // PLT relocations. 1374 bool is_got_plt_relro = parameters->options().now(); 1375 Output_section_order got_order = (is_got_plt_relro 1376 ? ORDER_RELRO 1377 : ORDER_RELRO_LAST); 1378 Output_section_order got_plt_order = (is_got_plt_relro 1379 ? ORDER_RELRO 1380 : ORDER_NON_RELRO_FIRST); 1381 1382 this->got_ = new Output_data_got<64, false>(); 1383 1384 layout->add_output_section_data(".got", elfcpp::SHT_PROGBITS, 1385 (elfcpp::SHF_ALLOC 1386 | elfcpp::SHF_WRITE), 1387 this->got_, got_order, true); 1388 1389 this->got_plt_ = new Output_data_got_plt_x86_64(layout); 1390 layout->add_output_section_data(".got.plt", elfcpp::SHT_PROGBITS, 1391 (elfcpp::SHF_ALLOC 1392 | elfcpp::SHF_WRITE), 1393 this->got_plt_, got_plt_order, 1394 is_got_plt_relro); 1395 1396 // The first three entries are reserved. 1397 this->got_plt_->set_current_data_size(3 * 8); 1398 1399 if (!is_got_plt_relro) 1400 { 1401 // Those bytes can go into the relro segment. 1402 layout->increase_relro(3 * 8); 1403 } 1404 1405 // Define _GLOBAL_OFFSET_TABLE_ at the start of the PLT. 1406 this->global_offset_table_ = 1407 symtab->define_in_output_data("_GLOBAL_OFFSET_TABLE_", NULL, 1408 Symbol_table::PREDEFINED, 1409 this->got_plt_, 1410 0, 0, elfcpp::STT_OBJECT, 1411 elfcpp::STB_LOCAL, 1412 elfcpp::STV_HIDDEN, 0, 1413 false, false); 1414 1415 // If there are any IRELATIVE relocations, they get GOT entries 1416 // in .got.plt after the jump slot entries. 1417 this->got_irelative_ = new Output_data_space(8, "** GOT IRELATIVE PLT"); 1418 layout->add_output_section_data(".got.plt", elfcpp::SHT_PROGBITS, 1419 (elfcpp::SHF_ALLOC 1420 | elfcpp::SHF_WRITE), 1421 this->got_irelative_, 1422 got_plt_order, is_got_plt_relro); 1423 1424 // If there are any TLSDESC relocations, they get GOT entries in 1425 // .got.plt after the jump slot and IRELATIVE entries. 1426 this->got_tlsdesc_ = new Output_data_got<64, false>(); 1427 layout->add_output_section_data(".got.plt", elfcpp::SHT_PROGBITS, 1428 (elfcpp::SHF_ALLOC 1429 | elfcpp::SHF_WRITE), 1430 this->got_tlsdesc_, 1431 got_plt_order, is_got_plt_relro); 1432 } 1433 1434 return this->got_; 1435 } 1436 1437 // Get the dynamic reloc section, creating it if necessary. 1438 1439 template<int size> 1440 typename Target_x86_64<size>::Reloc_section* 1441 Target_x86_64<size>::rela_dyn_section(Layout* layout) 1442 { 1443 if (this->rela_dyn_ == NULL) 1444 { 1445 gold_assert(layout != NULL); 1446 this->rela_dyn_ = new Reloc_section(parameters->options().combreloc()); 1447 layout->add_output_section_data(".rela.dyn", elfcpp::SHT_RELA, 1448 elfcpp::SHF_ALLOC, this->rela_dyn_, 1449 ORDER_DYNAMIC_RELOCS, false); 1450 } 1451 return this->rela_dyn_; 1452 } 1453 1454 // Get the section to use for IRELATIVE relocs, creating it if 1455 // necessary. These go in .rela.dyn, but only after all other dynamic 1456 // relocations. They need to follow the other dynamic relocations so 1457 // that they can refer to global variables initialized by those 1458 // relocs. 1459 1460 template<int size> 1461 typename Target_x86_64<size>::Reloc_section* 1462 Target_x86_64<size>::rela_irelative_section(Layout* layout) 1463 { 1464 if (this->rela_irelative_ == NULL) 1465 { 1466 // Make sure we have already created the dynamic reloc section. 1467 this->rela_dyn_section(layout); 1468 this->rela_irelative_ = new Reloc_section(false); 1469 layout->add_output_section_data(".rela.dyn", elfcpp::SHT_RELA, 1470 elfcpp::SHF_ALLOC, this->rela_irelative_, 1471 ORDER_DYNAMIC_RELOCS, false); 1472 gold_assert(this->rela_dyn_->output_section() 1473 == this->rela_irelative_->output_section()); 1474 } 1475 return this->rela_irelative_; 1476 } 1477 1478 // Record a target-specific program property from the .note.gnu.property 1479 // section. 1480 template<int size> 1481 void 1482 Target_x86_64<size>::record_gnu_property( 1483 unsigned int, unsigned int pr_type, 1484 size_t pr_datasz, const unsigned char* pr_data, 1485 const Object* object) 1486 { 1487 uint32_t val = 0; 1488 1489 switch (pr_type) 1490 { 1491 case elfcpp::GNU_PROPERTY_X86_COMPAT_ISA_1_USED: 1492 case elfcpp::GNU_PROPERTY_X86_COMPAT_ISA_1_NEEDED: 1493 case elfcpp::GNU_PROPERTY_X86_COMPAT_2_ISA_1_USED: 1494 case elfcpp::GNU_PROPERTY_X86_COMPAT_2_ISA_1_NEEDED: 1495 case elfcpp::GNU_PROPERTY_X86_ISA_1_USED: 1496 case elfcpp::GNU_PROPERTY_X86_ISA_1_NEEDED: 1497 case elfcpp::GNU_PROPERTY_X86_FEATURE_1_AND: 1498 case elfcpp::GNU_PROPERTY_X86_FEATURE_2_USED: 1499 case elfcpp::GNU_PROPERTY_X86_FEATURE_2_NEEDED: 1500 if (pr_datasz != 4) 1501 { 1502 gold_warning(_("%s: corrupt .note.gnu.property section " 1503 "(pr_datasz for property %d is not 4)"), 1504 object->name().c_str(), pr_type); 1505 return; 1506 } 1507 val = elfcpp::Swap<32, false>::readval(pr_data); 1508 break; 1509 default: 1510 gold_warning(_("%s: unknown program property type 0x%x " 1511 "in .note.gnu.property section"), 1512 object->name().c_str(), pr_type); 1513 break; 1514 } 1515 1516 switch (pr_type) 1517 { 1518 case elfcpp::GNU_PROPERTY_X86_ISA_1_USED: 1519 this->object_isa_1_used_ |= val; 1520 break; 1521 case elfcpp::GNU_PROPERTY_X86_ISA_1_NEEDED: 1522 this->isa_1_needed_ |= val; 1523 break; 1524 case elfcpp::GNU_PROPERTY_X86_FEATURE_1_AND: 1525 // If we see multiple feature props in one object, OR them together. 1526 this->object_feature_1_ |= val; 1527 break; 1528 case elfcpp::GNU_PROPERTY_X86_FEATURE_2_USED: 1529 this->object_feature_2_used_ |= val; 1530 break; 1531 case elfcpp::GNU_PROPERTY_X86_FEATURE_2_NEEDED: 1532 this->feature_2_needed_ |= val; 1533 break; 1534 } 1535 } 1536 1537 // Merge the target-specific program properties from the current object. 1538 template<int size> 1539 void 1540 Target_x86_64<size>::merge_gnu_properties(const Object*) 1541 { 1542 if (this->seen_first_object_) 1543 { 1544 // If any object is missing the ISA_1_USED property, we must omit 1545 // it from the output file. 1546 if (this->object_isa_1_used_ == 0) 1547 this->isa_1_used_ = 0; 1548 else if (this->isa_1_used_ != 0) 1549 this->isa_1_used_ |= this->object_isa_1_used_; 1550 this->feature_1_ &= this->object_feature_1_; 1551 // If any object is missing the FEATURE_2_USED property, we must 1552 // omit it from the output file. 1553 if (this->object_feature_2_used_ == 0) 1554 this->feature_2_used_ = 0; 1555 else if (this->feature_2_used_ != 0) 1556 this->feature_2_used_ |= this->object_feature_2_used_; 1557 } 1558 else 1559 { 1560 this->isa_1_used_ = this->object_isa_1_used_; 1561 this->feature_1_ = this->object_feature_1_; 1562 this->feature_2_used_ = this->object_feature_2_used_; 1563 this->seen_first_object_ = true; 1564 } 1565 this->object_isa_1_used_ = 0; 1566 this->object_feature_1_ = 0; 1567 this->object_feature_2_used_ = 0; 1568 } 1569 1570 static inline void 1571 add_property(Layout* layout, unsigned int pr_type, uint32_t val) 1572 { 1573 unsigned char buf[4]; 1574 elfcpp::Swap<32, false>::writeval(buf, val); 1575 layout->add_gnu_property(elfcpp::NT_GNU_PROPERTY_TYPE_0, pr_type, 4, buf); 1576 } 1577 1578 // Finalize the target-specific program properties and add them back to 1579 // the layout. 1580 template<int size> 1581 void 1582 Target_x86_64<size>::do_finalize_gnu_properties(Layout* layout) const 1583 { 1584 if (this->isa_1_used_ != 0) 1585 add_property(layout, elfcpp::GNU_PROPERTY_X86_ISA_1_USED, 1586 this->isa_1_used_); 1587 if (this->isa_1_needed_ != 0) 1588 add_property(layout, elfcpp::GNU_PROPERTY_X86_ISA_1_NEEDED, 1589 this->isa_1_needed_); 1590 if (this->feature_1_ != 0) 1591 add_property(layout, elfcpp::GNU_PROPERTY_X86_FEATURE_1_AND, 1592 this->feature_1_); 1593 if (this->feature_2_used_ != 0) 1594 add_property(layout, elfcpp::GNU_PROPERTY_X86_FEATURE_2_USED, 1595 this->feature_2_used_); 1596 if (this->feature_2_needed_ != 0) 1597 add_property(layout, elfcpp::GNU_PROPERTY_X86_FEATURE_2_NEEDED, 1598 this->feature_2_needed_); 1599 } 1600 1601 // Write the first three reserved words of the .got.plt section. 1602 // The remainder of the section is written while writing the PLT 1603 // in Output_data_plt_i386::do_write. 1604 1605 void 1606 Output_data_got_plt_x86_64::do_write(Output_file* of) 1607 { 1608 // The first entry in the GOT is the address of the .dynamic section 1609 // aka the PT_DYNAMIC segment. The next two entries are reserved. 1610 // We saved space for them when we created the section in 1611 // Target_x86_64::got_section. 1612 const off_t got_file_offset = this->offset(); 1613 gold_assert(this->data_size() >= 24); 1614 unsigned char* const got_view = of->get_output_view(got_file_offset, 24); 1615 Output_section* dynamic = this->layout_->dynamic_section(); 1616 uint64_t dynamic_addr = dynamic == NULL ? 0 : dynamic->address(); 1617 elfcpp::Swap<64, false>::writeval(got_view, dynamic_addr); 1618 memset(got_view + 8, 0, 16); 1619 of->write_output_view(got_file_offset, 24, got_view); 1620 } 1621 1622 // Initialize the PLT section. 1623 1624 template<int size> 1625 void 1626 Output_data_plt_x86_64<size>::init(Layout* layout) 1627 { 1628 this->rel_ = new Reloc_section(false); 1629 layout->add_output_section_data(".rela.plt", elfcpp::SHT_RELA, 1630 elfcpp::SHF_ALLOC, this->rel_, 1631 ORDER_DYNAMIC_PLT_RELOCS, false); 1632 } 1633 1634 template<int size> 1635 void 1636 Output_data_plt_x86_64<size>::do_adjust_output_section(Output_section* os) 1637 { 1638 os->set_entsize(this->get_plt_entry_size()); 1639 } 1640 1641 // Add an entry to the PLT. 1642 1643 template<int size> 1644 void 1645 Output_data_plt_x86_64<size>::add_entry(Symbol_table* symtab, Layout* layout, 1646 Symbol* gsym) 1647 { 1648 gold_assert(!gsym->has_plt_offset()); 1649 1650 unsigned int plt_index; 1651 off_t plt_offset; 1652 section_offset_type got_offset; 1653 1654 unsigned int* pcount; 1655 unsigned int offset; 1656 unsigned int reserved; 1657 Output_section_data_build* got; 1658 if (gsym->type() == elfcpp::STT_GNU_IFUNC 1659 && gsym->can_use_relative_reloc(false)) 1660 { 1661 pcount = &this->irelative_count_; 1662 offset = 0; 1663 reserved = 0; 1664 got = this->got_irelative_; 1665 } 1666 else 1667 { 1668 pcount = &this->count_; 1669 offset = 1; 1670 reserved = 3; 1671 got = this->got_plt_; 1672 } 1673 1674 if (!this->is_data_size_valid()) 1675 { 1676 // Note that when setting the PLT offset for a non-IRELATIVE 1677 // entry we skip the initial reserved PLT entry. 1678 plt_index = *pcount + offset; 1679 plt_offset = plt_index * this->get_plt_entry_size(); 1680 1681 ++*pcount; 1682 1683 got_offset = (plt_index - offset + reserved) * 8; 1684 gold_assert(got_offset == got->current_data_size()); 1685 1686 // Every PLT entry needs a GOT entry which points back to the PLT 1687 // entry (this will be changed by the dynamic linker, normally 1688 // lazily when the function is called). 1689 got->set_current_data_size(got_offset + 8); 1690 } 1691 else 1692 { 1693 // FIXME: This is probably not correct for IRELATIVE relocs. 1694 1695 // For incremental updates, find an available slot. 1696 plt_offset = this->free_list_.allocate(this->get_plt_entry_size(), 1697 this->get_plt_entry_size(), 0); 1698 if (plt_offset == -1) 1699 gold_fallback(_("out of patch space (PLT);" 1700 " relink with --incremental-full")); 1701 1702 // The GOT and PLT entries have a 1-1 correspondance, so the GOT offset 1703 // can be calculated from the PLT index, adjusting for the three 1704 // reserved entries at the beginning of the GOT. 1705 plt_index = plt_offset / this->get_plt_entry_size() - 1; 1706 got_offset = (plt_index - offset + reserved) * 8; 1707 } 1708 1709 gsym->set_plt_offset(plt_offset); 1710 1711 // Every PLT entry needs a reloc. 1712 this->add_relocation(symtab, layout, gsym, got_offset); 1713 1714 // Note that we don't need to save the symbol. The contents of the 1715 // PLT are independent of which symbols are used. The symbols only 1716 // appear in the relocations. 1717 } 1718 1719 // Add an entry to the PLT for a local STT_GNU_IFUNC symbol. Return 1720 // the PLT offset. 1721 1722 template<int size> 1723 unsigned int 1724 Output_data_plt_x86_64<size>::add_local_ifunc_entry( 1725 Symbol_table* symtab, 1726 Layout* layout, 1727 Sized_relobj_file<size, false>* relobj, 1728 unsigned int local_sym_index) 1729 { 1730 unsigned int plt_offset = this->irelative_count_ * this->get_plt_entry_size(); 1731 ++this->irelative_count_; 1732 1733 section_offset_type got_offset = this->got_irelative_->current_data_size(); 1734 1735 // Every PLT entry needs a GOT entry which points back to the PLT 1736 // entry. 1737 this->got_irelative_->set_current_data_size(got_offset + 8); 1738 1739 // Every PLT entry needs a reloc. 1740 Reloc_section* rela = this->rela_irelative(symtab, layout); 1741 rela->add_symbolless_local_addend(relobj, local_sym_index, 1742 elfcpp::R_X86_64_IRELATIVE, 1743 this->got_irelative_, got_offset, 0); 1744 1745 return plt_offset; 1746 } 1747 1748 // Add the relocation for a PLT entry. 1749 1750 template<int size> 1751 void 1752 Output_data_plt_x86_64<size>::add_relocation(Symbol_table* symtab, 1753 Layout* layout, 1754 Symbol* gsym, 1755 unsigned int got_offset) 1756 { 1757 if (gsym->type() == elfcpp::STT_GNU_IFUNC 1758 && gsym->can_use_relative_reloc(false)) 1759 { 1760 Reloc_section* rela = this->rela_irelative(symtab, layout); 1761 rela->add_symbolless_global_addend(gsym, elfcpp::R_X86_64_IRELATIVE, 1762 this->got_irelative_, got_offset, 0); 1763 } 1764 else 1765 { 1766 gsym->set_needs_dynsym_entry(); 1767 this->rel_->add_global(gsym, elfcpp::R_X86_64_JUMP_SLOT, this->got_plt_, 1768 got_offset, 0); 1769 } 1770 } 1771 1772 // Return where the TLSDESC relocations should go, creating it if 1773 // necessary. These follow the JUMP_SLOT relocations. 1774 1775 template<int size> 1776 typename Output_data_plt_x86_64<size>::Reloc_section* 1777 Output_data_plt_x86_64<size>::rela_tlsdesc(Layout* layout) 1778 { 1779 if (this->tlsdesc_rel_ == NULL) 1780 { 1781 this->tlsdesc_rel_ = new Reloc_section(false); 1782 layout->add_output_section_data(".rela.plt", elfcpp::SHT_RELA, 1783 elfcpp::SHF_ALLOC, this->tlsdesc_rel_, 1784 ORDER_DYNAMIC_PLT_RELOCS, false); 1785 gold_assert(this->tlsdesc_rel_->output_section() 1786 == this->rel_->output_section()); 1787 } 1788 return this->tlsdesc_rel_; 1789 } 1790 1791 // Return where the IRELATIVE relocations should go in the PLT. These 1792 // follow the JUMP_SLOT and the TLSDESC relocations. 1793 1794 template<int size> 1795 typename Output_data_plt_x86_64<size>::Reloc_section* 1796 Output_data_plt_x86_64<size>::rela_irelative(Symbol_table* symtab, 1797 Layout* layout) 1798 { 1799 if (this->irelative_rel_ == NULL) 1800 { 1801 // Make sure we have a place for the TLSDESC relocations, in 1802 // case we see any later on. 1803 this->rela_tlsdesc(layout); 1804 this->irelative_rel_ = new Reloc_section(false); 1805 layout->add_output_section_data(".rela.plt", elfcpp::SHT_RELA, 1806 elfcpp::SHF_ALLOC, this->irelative_rel_, 1807 ORDER_DYNAMIC_PLT_RELOCS, false); 1808 gold_assert(this->irelative_rel_->output_section() 1809 == this->rel_->output_section()); 1810 1811 if (parameters->doing_static_link()) 1812 { 1813 // A statically linked executable will only have a .rela.plt 1814 // section to hold R_X86_64_IRELATIVE relocs for 1815 // STT_GNU_IFUNC symbols. The library will use these 1816 // symbols to locate the IRELATIVE relocs at program startup 1817 // time. 1818 symtab->define_in_output_data("__rela_iplt_start", NULL, 1819 Symbol_table::PREDEFINED, 1820 this->irelative_rel_, 0, 0, 1821 elfcpp::STT_NOTYPE, elfcpp::STB_GLOBAL, 1822 elfcpp::STV_HIDDEN, 0, false, true); 1823 symtab->define_in_output_data("__rela_iplt_end", NULL, 1824 Symbol_table::PREDEFINED, 1825 this->irelative_rel_, 0, 0, 1826 elfcpp::STT_NOTYPE, elfcpp::STB_GLOBAL, 1827 elfcpp::STV_HIDDEN, 0, true, true); 1828 } 1829 } 1830 return this->irelative_rel_; 1831 } 1832 1833 // Return the PLT address to use for a global symbol. 1834 1835 template<int size> 1836 uint64_t 1837 Output_data_plt_x86_64<size>::do_address_for_global(const Symbol* gsym) 1838 { 1839 uint64_t offset = 0; 1840 if (gsym->type() == elfcpp::STT_GNU_IFUNC 1841 && gsym->can_use_relative_reloc(false)) 1842 offset = (this->count_ + 1) * this->get_plt_entry_size(); 1843 return this->address() + offset + gsym->plt_offset(); 1844 } 1845 1846 // Return the PLT address to use for a local symbol. These are always 1847 // IRELATIVE relocs. 1848 1849 template<int size> 1850 uint64_t 1851 Output_data_plt_x86_64<size>::do_address_for_local(const Relobj* object, 1852 unsigned int r_sym) 1853 { 1854 return (this->address() 1855 + (this->count_ + 1) * this->get_plt_entry_size() 1856 + object->local_plt_offset(r_sym)); 1857 } 1858 1859 // Set the final size. 1860 template<int size> 1861 void 1862 Output_data_plt_x86_64<size>::set_final_data_size() 1863 { 1864 // Number of regular and IFUNC PLT entries, plus the first entry. 1865 unsigned int count = this->count_ + this->irelative_count_ + 1; 1866 // Count the TLSDESC entry, if present. 1867 if (this->has_tlsdesc_entry()) 1868 ++count; 1869 this->set_data_size(count * this->get_plt_entry_size()); 1870 } 1871 1872 // The first entry in the PLT for an executable. 1873 1874 template<int size> 1875 const unsigned char 1876 Output_data_plt_x86_64_standard<size>::first_plt_entry[plt_entry_size] = 1877 { 1878 // From AMD64 ABI Draft 0.98, page 76 1879 0xff, 0x35, // pushq contents of memory address 1880 0, 0, 0, 0, // replaced with address of .got + 8 1881 0xff, 0x25, // jmp indirect 1882 0, 0, 0, 0, // replaced with address of .got + 16 1883 0x90, 0x90, 0x90, 0x90 // noop (x4) 1884 }; 1885 1886 template<int size> 1887 void 1888 Output_data_plt_x86_64_standard<size>::do_fill_first_plt_entry( 1889 unsigned char* pov, 1890 typename elfcpp::Elf_types<size>::Elf_Addr got_address, 1891 typename elfcpp::Elf_types<size>::Elf_Addr plt_address) 1892 { 1893 memcpy(pov, first_plt_entry, plt_entry_size); 1894 // We do a jmp relative to the PC at the end of this instruction. 1895 elfcpp::Swap_unaligned<32, false>::writeval(pov + 2, 1896 (got_address + 8 1897 - (plt_address + 6))); 1898 elfcpp::Swap<32, false>::writeval(pov + 8, 1899 (got_address + 16 1900 - (plt_address + 12))); 1901 } 1902 1903 // Subsequent entries in the PLT for an executable. 1904 1905 template<int size> 1906 const unsigned char 1907 Output_data_plt_x86_64_standard<size>::plt_entry[plt_entry_size] = 1908 { 1909 // From AMD64 ABI Draft 0.98, page 76 1910 0xff, 0x25, // jmpq indirect 1911 0, 0, 0, 0, // replaced with address of symbol in .got 1912 0x68, // pushq immediate 1913 0, 0, 0, 0, // replaced with offset into relocation table 1914 0xe9, // jmpq relative 1915 0, 0, 0, 0 // replaced with offset to start of .plt 1916 }; 1917 1918 template<int size> 1919 unsigned int 1920 Output_data_plt_x86_64_standard<size>::do_fill_plt_entry( 1921 unsigned char* pov, 1922 typename elfcpp::Elf_types<size>::Elf_Addr got_address, 1923 typename elfcpp::Elf_types<size>::Elf_Addr plt_address, 1924 unsigned int got_offset, 1925 unsigned int plt_offset, 1926 unsigned int plt_index) 1927 { 1928 // Check PC-relative offset overflow in PLT entry. 1929 uint64_t plt_got_pcrel_offset = (got_address + got_offset 1930 - (plt_address + plt_offset + 6)); 1931 if (Bits<32>::has_overflow(plt_got_pcrel_offset)) 1932 gold_error(_("PC-relative offset overflow in PLT entry %d"), 1933 plt_index + 1); 1934 1935 memcpy(pov, plt_entry, plt_entry_size); 1936 elfcpp::Swap_unaligned<32, false>::writeval(pov + 2, 1937 plt_got_pcrel_offset); 1938 1939 elfcpp::Swap_unaligned<32, false>::writeval(pov + 7, plt_index); 1940 elfcpp::Swap<32, false>::writeval(pov + 12, 1941 - (plt_offset + plt_entry_size)); 1942 1943 return 6; 1944 } 1945 1946 // The reserved TLSDESC entry in the PLT for an executable. 1947 1948 template<int size> 1949 const unsigned char 1950 Output_data_plt_x86_64_standard<size>::tlsdesc_plt_entry[plt_entry_size] = 1951 { 1952 // From Alexandre Oliva, "Thread-Local Storage Descriptors for IA32 1953 // and AMD64/EM64T", Version 0.9.4 (2005-10-10). 1954 0xff, 0x35, // pushq x(%rip) 1955 0, 0, 0, 0, // replaced with address of linkmap GOT entry (at PLTGOT + 8) 1956 0xff, 0x25, // jmpq *y(%rip) 1957 0, 0, 0, 0, // replaced with offset of reserved TLSDESC_GOT entry 1958 0x0f, 0x1f, // nop 1959 0x40, 0 1960 }; 1961 1962 template<int size> 1963 void 1964 Output_data_plt_x86_64_standard<size>::do_fill_tlsdesc_entry( 1965 unsigned char* pov, 1966 typename elfcpp::Elf_types<size>::Elf_Addr got_address, 1967 typename elfcpp::Elf_types<size>::Elf_Addr plt_address, 1968 typename elfcpp::Elf_types<size>::Elf_Addr got_base, 1969 unsigned int tlsdesc_got_offset, 1970 unsigned int plt_offset) 1971 { 1972 memcpy(pov, tlsdesc_plt_entry, plt_entry_size); 1973 elfcpp::Swap_unaligned<32, false>::writeval(pov + 2, 1974 (got_address + 8 1975 - (plt_address + plt_offset 1976 + 6))); 1977 elfcpp::Swap_unaligned<32, false>::writeval(pov + 8, 1978 (got_base 1979 + tlsdesc_got_offset 1980 - (plt_address + plt_offset 1981 + 12))); 1982 } 1983 1984 // Return the APLT address to use for a global symbol (for IBT). 1985 1986 template<int size> 1987 uint64_t 1988 Output_data_plt_x86_64_ibt<size>::do_address_for_global(const Symbol* gsym) 1989 { 1990 uint64_t offset = this->aplt_offset_; 1991 // Convert the PLT offset into an APLT offset. 1992 unsigned int plt_offset = gsym->plt_offset(); 1993 if (gsym->type() == elfcpp::STT_GNU_IFUNC 1994 && gsym->can_use_relative_reloc(false)) 1995 offset += this->regular_count() * aplt_entry_size; 1996 else 1997 plt_offset -= plt_entry_size; 1998 plt_offset = plt_offset / (plt_entry_size / aplt_entry_size); 1999 return this->address() + offset + plt_offset; 2000 } 2001 2002 // Return the PLT address to use for a local symbol. These are always 2003 // IRELATIVE relocs. 2004 2005 template<int size> 2006 uint64_t 2007 Output_data_plt_x86_64_ibt<size>::do_address_for_local(const Relobj* object, 2008 unsigned int r_sym) 2009 { 2010 // Convert the PLT offset into an APLT offset. 2011 const Sized_relobj_file<size, false>* sized_relobj = 2012 static_cast<const Sized_relobj_file<size, false>*>(object); 2013 const Symbol_value<size>* psymval = sized_relobj->local_symbol(r_sym); 2014 unsigned int plt_offset = ((object->local_plt_offset(r_sym) 2015 - (psymval->is_ifunc_symbol() 2016 ? 0 : plt_entry_size)) 2017 / (plt_entry_size / aplt_entry_size)); 2018 return (this->address() 2019 + this->aplt_offset_ 2020 + this->regular_count() * aplt_entry_size 2021 + plt_offset); 2022 } 2023 2024 // Set the final size. 2025 2026 template<int size> 2027 void 2028 Output_data_plt_x86_64_ibt<size>::set_final_data_size() 2029 { 2030 // Number of regular and IFUNC PLT entries. 2031 unsigned int count = this->entry_count(); 2032 // Count the first entry and the TLSDESC entry, if present. 2033 unsigned int extra = this->has_tlsdesc_entry() ? 2 : 1; 2034 unsigned int plt_size = (count + extra) * plt_entry_size; 2035 // Offset of the APLT. 2036 this->aplt_offset_ = plt_size; 2037 // Size of the APLT. 2038 plt_size += count * aplt_entry_size; 2039 this->set_data_size(plt_size); 2040 } 2041 2042 // The first entry in the IBT PLT. 2043 2044 template<int size> 2045 const unsigned char 2046 Output_data_plt_x86_64_ibt<size>::first_plt_entry[plt_entry_size] = 2047 { 2048 0xff, 0x35, // pushq contents of memory address 2049 0, 0, 0, 0, // replaced with address of .got + 8 2050 0xff, 0x25, // jmp indirect 2051 0, 0, 0, 0, // replaced with address of .got + 16 2052 0x90, 0x90, 0x90, 0x90 // noop (x4) 2053 }; 2054 2055 template<int size> 2056 void 2057 Output_data_plt_x86_64_ibt<size>::do_fill_first_plt_entry( 2058 unsigned char* pov, 2059 typename elfcpp::Elf_types<size>::Elf_Addr got_address, 2060 typename elfcpp::Elf_types<size>::Elf_Addr plt_address) 2061 { 2062 // Offsets to the addresses needing relocation. 2063 const unsigned int roff1 = 2; 2064 const unsigned int roff2 = 8; 2065 2066 memcpy(pov, first_plt_entry, plt_entry_size); 2067 // We do a jmp relative to the PC at the end of this instruction. 2068 elfcpp::Swap_unaligned<32, false>::writeval(pov + roff1, 2069 (got_address + 8 2070 - (plt_address + roff1 + 4))); 2071 elfcpp::Swap<32, false>::writeval(pov + roff2, 2072 (got_address + 16 2073 - (plt_address + roff2 + 4))); 2074 } 2075 2076 // Subsequent entries in the IBT PLT. 2077 2078 template<int size> 2079 const unsigned char 2080 Output_data_plt_x86_64_ibt<size>::plt_entry[plt_entry_size] = 2081 { 2082 // From AMD64 ABI Draft 1.0-rc1, Chapter 13. 2083 0xf3, 0x0f, 0x1e, 0xfa, // endbr64 2084 0x68, // pushq immediate 2085 0, 0, 0, 0, // replaced with offset into relocation table 2086 0xe9, // jmpq relative 2087 0, 0, 0, 0, // replaced with offset to start of .plt 2088 0x90, 0x90 // nop 2089 }; 2090 2091 // Entries in the IBT Additional PLT. 2092 2093 template<int size> 2094 const unsigned char 2095 Output_data_plt_x86_64_ibt<size>::aplt_entry[aplt_entry_size] = 2096 { 2097 // From AMD64 ABI Draft 1.0-rc1, Chapter 13. 2098 0xf3, 0x0f, 0x1e, 0xfa, // endbr64 2099 0xff, 0x25, // jmpq indirect 2100 0, 0, 0, 0, // replaced with address of symbol in .got 2101 0x0f, 0x1f, 0x04, 0x00, // nop 2102 0x90, 0x90 // nop 2103 }; 2104 2105 template<int size> 2106 unsigned int 2107 Output_data_plt_x86_64_ibt<size>::do_fill_plt_entry( 2108 unsigned char* pov, 2109 typename elfcpp::Elf_types<size>::Elf_Addr, 2110 typename elfcpp::Elf_types<size>::Elf_Addr, 2111 unsigned int, 2112 unsigned int plt_offset, 2113 unsigned int plt_index) 2114 { 2115 // Offsets to the addresses needing relocation. 2116 const unsigned int roff1 = 5; 2117 const unsigned int roff2 = 10; 2118 2119 memcpy(pov, plt_entry, plt_entry_size); 2120 elfcpp::Swap_unaligned<32, false>::writeval(pov + roff1, plt_index); 2121 elfcpp::Swap<32, false>::writeval(pov + roff2, -(plt_offset + roff2 + 4)); 2122 return 0; 2123 } 2124 2125 template<int size> 2126 void 2127 Output_data_plt_x86_64_ibt<size>::fill_aplt_entry( 2128 unsigned char* pov, 2129 typename elfcpp::Elf_types<size>::Elf_Addr got_address, 2130 typename elfcpp::Elf_types<size>::Elf_Addr plt_address, 2131 unsigned int got_offset, 2132 unsigned int plt_offset, 2133 unsigned int plt_index) 2134 { 2135 // Offset to the address needing relocation. 2136 const unsigned int roff = 6; 2137 2138 // Check PC-relative offset overflow in PLT entry. 2139 uint64_t plt_got_pcrel_offset = (got_address + got_offset 2140 - (plt_address + plt_offset + roff + 4)); 2141 if (Bits<32>::has_overflow(plt_got_pcrel_offset)) 2142 gold_error(_("PC-relative offset overflow in APLT entry %d"), 2143 plt_index + 1); 2144 2145 memcpy(pov, aplt_entry, aplt_entry_size); 2146 elfcpp::Swap_unaligned<32, false>::writeval(pov + roff, plt_got_pcrel_offset); 2147 } 2148 2149 // The reserved TLSDESC entry in the IBT PLT for an executable. 2150 2151 template<int size> 2152 const unsigned char 2153 Output_data_plt_x86_64_ibt<size>::tlsdesc_plt_entry[plt_entry_size] = 2154 { 2155 // From Alexandre Oliva, "Thread-Local Storage Descriptors for IA32 2156 // and AMD64/EM64T", Version 0.9.4 (2005-10-10). 2157 0xf3, 0x0f, 0x1e, 0xfa, // endbr64 2158 0xff, 0x35, // pushq x(%rip) 2159 0, 0, 0, 0, // replaced with address of linkmap GOT entry (at PLTGOT + 8) 2160 0xff, 0x25, // jmpq *y(%rip) 2161 0, 0, 0, 0, // replaced with offset of reserved TLSDESC_GOT entry 2162 }; 2163 2164 template<int size> 2165 void 2166 Output_data_plt_x86_64_ibt<size>::do_fill_tlsdesc_entry( 2167 unsigned char* pov, 2168 typename elfcpp::Elf_types<size>::Elf_Addr got_address, 2169 typename elfcpp::Elf_types<size>::Elf_Addr plt_address, 2170 typename elfcpp::Elf_types<size>::Elf_Addr got_base, 2171 unsigned int tlsdesc_got_offset, 2172 unsigned int plt_offset) 2173 { 2174 memcpy(pov, tlsdesc_plt_entry, plt_entry_size); 2175 elfcpp::Swap_unaligned<32, false>::writeval(pov + 6, 2176 (got_address + 8 2177 - (plt_address + plt_offset 2178 + 10))); 2179 elfcpp::Swap_unaligned<32, false>::writeval(pov + 12, 2180 (got_base 2181 + tlsdesc_got_offset 2182 - (plt_address + plt_offset 2183 + 16))); 2184 } 2185 2186 // The .eh_frame unwind information for the PLT. 2187 2188 template<int size> 2189 const unsigned char 2190 Output_data_plt_x86_64<size>::plt_eh_frame_cie[plt_eh_frame_cie_size] = 2191 { 2192 1, // CIE version. 2193 'z', // Augmentation: augmentation size included. 2194 'R', // Augmentation: FDE encoding included. 2195 '\0', // End of augmentation string. 2196 1, // Code alignment factor. 2197 0x78, // Data alignment factor. 2198 16, // Return address column. 2199 1, // Augmentation size. 2200 (elfcpp::DW_EH_PE_pcrel // FDE encoding. 2201 | elfcpp::DW_EH_PE_sdata4), 2202 elfcpp::DW_CFA_def_cfa, 7, 8, // DW_CFA_def_cfa: r7 (rsp) ofs 8. 2203 elfcpp::DW_CFA_offset + 16, 1,// DW_CFA_offset: r16 (rip) at cfa-8. 2204 elfcpp::DW_CFA_nop, // Align to 16 bytes. 2205 elfcpp::DW_CFA_nop 2206 }; 2207 2208 template<int size> 2209 const unsigned char 2210 Output_data_plt_x86_64_standard<size>::plt_eh_frame_fde[plt_eh_frame_fde_size] = 2211 { 2212 0, 0, 0, 0, // Replaced with offset to .plt. 2213 0, 0, 0, 0, // Replaced with size of .plt. 2214 0, // Augmentation size. 2215 elfcpp::DW_CFA_def_cfa_offset, 16, // DW_CFA_def_cfa_offset: 16. 2216 elfcpp::DW_CFA_advance_loc + 6, // Advance 6 to __PLT__ + 6. 2217 elfcpp::DW_CFA_def_cfa_offset, 24, // DW_CFA_def_cfa_offset: 24. 2218 elfcpp::DW_CFA_advance_loc + 10, // Advance 10 to __PLT__ + 16. 2219 elfcpp::DW_CFA_def_cfa_expression, // DW_CFA_def_cfa_expression. 2220 11, // Block length. 2221 elfcpp::DW_OP_breg7, 8, // Push %rsp + 8. 2222 elfcpp::DW_OP_breg16, 0, // Push %rip. 2223 elfcpp::DW_OP_lit15, // Push 0xf. 2224 elfcpp::DW_OP_and, // & (%rip & 0xf). 2225 elfcpp::DW_OP_lit11, // Push 0xb. 2226 elfcpp::DW_OP_ge, // >= ((%rip & 0xf) >= 0xb) 2227 elfcpp::DW_OP_lit3, // Push 3. 2228 elfcpp::DW_OP_shl, // << (((%rip & 0xf) >= 0xb) << 3) 2229 elfcpp::DW_OP_plus, // + ((((%rip&0xf)>=0xb)<<3)+%rsp+8 2230 elfcpp::DW_CFA_nop, // Align to 32 bytes. 2231 elfcpp::DW_CFA_nop, 2232 elfcpp::DW_CFA_nop, 2233 elfcpp::DW_CFA_nop 2234 }; 2235 2236 // The .eh_frame unwind information for the PLT. 2237 template<int size> 2238 const unsigned char 2239 Output_data_plt_x86_64_ibt<size>::plt_eh_frame_fde[plt_eh_frame_fde_size] = 2240 { 2241 0, 0, 0, 0, // Replaced with offset to .plt. 2242 0, 0, 0, 0, // Replaced with size of .plt. 2243 0, // Augmentation size. 2244 elfcpp::DW_CFA_def_cfa_offset, 16, // DW_CFA_def_cfa_offset: 16. 2245 elfcpp::DW_CFA_advance_loc + 6, // Advance 6 to __PLT__ + 6. 2246 elfcpp::DW_CFA_def_cfa_offset, 24, // DW_CFA_def_cfa_offset: 24. 2247 elfcpp::DW_CFA_advance_loc + 10, // Advance 10 to __PLT__ + 16. 2248 elfcpp::DW_CFA_def_cfa_expression, // DW_CFA_def_cfa_expression. 2249 11, // Block length. 2250 elfcpp::DW_OP_breg7, 8, // Push %rsp + 8. 2251 elfcpp::DW_OP_breg16, 0, // Push %rip. 2252 elfcpp::DW_OP_lit15, // Push 0xf. 2253 elfcpp::DW_OP_and, // & (%rip & 0xf). 2254 elfcpp::DW_OP_lit9, // Push 9. 2255 elfcpp::DW_OP_ge, // >= ((%rip & 0xf) >= 9) 2256 elfcpp::DW_OP_lit3, // Push 3. 2257 elfcpp::DW_OP_shl, // << (((%rip & 0xf) >= 9) << 3) 2258 elfcpp::DW_OP_plus, // + ((((%rip&0xf)>=9)<<3)+%rsp+8 2259 elfcpp::DW_CFA_nop, // Align to 32 bytes. 2260 elfcpp::DW_CFA_nop, 2261 elfcpp::DW_CFA_nop, 2262 elfcpp::DW_CFA_nop 2263 }; 2264 2265 // Write out the PLT. This uses the hand-coded instructions above, 2266 // and adjusts them as needed. This is specified by the AMD64 ABI. 2267 2268 template<int size> 2269 void 2270 Output_data_plt_x86_64<size>::do_write(Output_file* of) 2271 { 2272 const off_t offset = this->offset(); 2273 const section_size_type oview_size = 2274 convert_to_section_size_type(this->data_size()); 2275 unsigned char* const oview = of->get_output_view(offset, oview_size); 2276 2277 const off_t got_file_offset = this->got_plt_->offset(); 2278 gold_assert(parameters->incremental_update() 2279 || (got_file_offset + this->got_plt_->data_size() 2280 == this->got_irelative_->offset())); 2281 const section_size_type got_size = 2282 convert_to_section_size_type(this->got_plt_->data_size() 2283 + this->got_irelative_->data_size()); 2284 unsigned char* const got_view = of->get_output_view(got_file_offset, 2285 got_size); 2286 2287 unsigned char* pov = oview; 2288 2289 // The base address of the .plt section. 2290 typename elfcpp::Elf_types<size>::Elf_Addr plt_address = this->address(); 2291 // The base address of the .got section. 2292 typename elfcpp::Elf_types<size>::Elf_Addr got_base = this->got_->address(); 2293 // The base address of the PLT portion of the .got section, 2294 // which is where the GOT pointer will point, and where the 2295 // three reserved GOT entries are located. 2296 typename elfcpp::Elf_types<size>::Elf_Addr got_address 2297 = this->got_plt_->address(); 2298 2299 this->fill_first_plt_entry(pov, got_address, plt_address); 2300 pov += this->get_plt_entry_size(); 2301 2302 // The first three entries in the GOT are reserved, and are written 2303 // by Output_data_got_plt_x86_64::do_write. 2304 unsigned char* got_pov = got_view + 24; 2305 2306 unsigned int plt_offset = this->get_plt_entry_size(); 2307 unsigned int got_offset = 24; 2308 const unsigned int count = this->count_ + this->irelative_count_; 2309 for (unsigned int plt_index = 0; 2310 plt_index < count; 2311 ++plt_index, 2312 pov += this->get_plt_entry_size(), 2313 got_pov += 8, 2314 plt_offset += this->get_plt_entry_size(), 2315 got_offset += 8) 2316 { 2317 // Set and adjust the PLT entry itself. 2318 unsigned int lazy_offset = this->fill_plt_entry(pov, 2319 got_address, plt_address, 2320 got_offset, plt_offset, 2321 plt_index); 2322 2323 // Set the entry in the GOT. 2324 elfcpp::Swap<64, false>::writeval(got_pov, 2325 plt_address + plt_offset + lazy_offset); 2326 } 2327 2328 if (this->has_tlsdesc_entry()) 2329 { 2330 // Set and adjust the reserved TLSDESC PLT entry. 2331 unsigned int tlsdesc_got_offset = this->get_tlsdesc_got_offset(); 2332 this->fill_tlsdesc_entry(pov, got_address, plt_address, got_base, 2333 tlsdesc_got_offset, plt_offset); 2334 pov += this->get_plt_entry_size(); 2335 } 2336 2337 gold_assert(static_cast<section_size_type>(pov - oview) == oview_size); 2338 gold_assert(static_cast<section_size_type>(got_pov - got_view) == got_size); 2339 2340 of->write_output_view(offset, oview_size, oview); 2341 of->write_output_view(got_file_offset, got_size, got_view); 2342 } 2343 2344 // Write out the IBT PLT. 2345 2346 template<int size> 2347 void 2348 Output_data_plt_x86_64_ibt<size>::do_write(Output_file* of) 2349 { 2350 const off_t offset = this->offset(); 2351 const section_size_type oview_size = 2352 convert_to_section_size_type(this->data_size()); 2353 unsigned char* const oview = of->get_output_view(offset, oview_size); 2354 2355 Output_data_got<64, false>* got = this->got(); 2356 Output_data_got_plt_x86_64* got_plt = this->got_plt(); 2357 Output_data_space* got_irelative = this->got_irelative(); 2358 2359 const off_t got_file_offset = got_plt->offset(); 2360 gold_assert(parameters->incremental_update() 2361 || (got_file_offset + got_plt->data_size() 2362 == got_irelative->offset())); 2363 const section_size_type got_size = 2364 convert_to_section_size_type(got_plt->data_size() 2365 + got_irelative->data_size()); 2366 unsigned char* const got_view = of->get_output_view(got_file_offset, 2367 got_size); 2368 2369 unsigned char* pov = oview; 2370 2371 // The base address of the .plt section. 2372 elfcpp::Elf_types<64>::Elf_Addr plt_address = this->address(); 2373 // The base address of the .got section. 2374 elfcpp::Elf_types<64>::Elf_Addr got_base = got->address(); 2375 // The base address of the PLT portion of the .got section, 2376 // which is where the GOT pointer will point, and where the 2377 // three reserved GOT entries are located. 2378 elfcpp::Elf_types<64>::Elf_Addr got_address = got_plt->address(); 2379 2380 this->fill_first_plt_entry(pov, got_address, plt_address); 2381 pov += plt_entry_size; 2382 2383 // The first three entries in the GOT are reserved, and are written 2384 // by Output_data_got_plt_x86_64::do_write. 2385 unsigned char* got_pov = got_view + 24; 2386 2387 unsigned int plt_offset = plt_entry_size; 2388 unsigned int got_offset = 24; 2389 const unsigned int count = this->entry_count(); 2390 for (unsigned int plt_index = 0; 2391 plt_index < count; 2392 ++plt_index, 2393 pov += plt_entry_size, 2394 got_pov += 8, 2395 plt_offset += plt_entry_size, 2396 got_offset += 8) 2397 { 2398 // Set and adjust the PLT entry itself. 2399 unsigned int lazy_offset = this->fill_plt_entry(pov, 2400 got_address, plt_address, 2401 got_offset, plt_offset, 2402 plt_index); 2403 2404 // Set the entry in the GOT. 2405 elfcpp::Swap<64, false>::writeval(got_pov, 2406 plt_address + plt_offset + lazy_offset); 2407 } 2408 2409 if (this->has_tlsdesc_entry()) 2410 { 2411 // Set and adjust the reserved TLSDESC PLT entry. 2412 unsigned int tlsdesc_got_offset = this->get_tlsdesc_got_offset(); 2413 this->fill_tlsdesc_entry(pov, got_address, plt_address, got_base, 2414 tlsdesc_got_offset, plt_offset); 2415 pov += this->get_plt_entry_size(); 2416 plt_offset += plt_entry_size; 2417 } 2418 2419 // Write the additional PLT. 2420 got_offset = 24; 2421 for (unsigned int plt_index = 0; 2422 plt_index < count; 2423 ++plt_index, 2424 pov += aplt_entry_size, 2425 plt_offset += aplt_entry_size, 2426 got_offset += 8) 2427 { 2428 // Set and adjust the APLT entry. 2429 this->fill_aplt_entry(pov, got_address, plt_address, got_offset, 2430 plt_offset, plt_index); 2431 } 2432 2433 gold_assert(static_cast<section_size_type>(pov - oview) == oview_size); 2434 gold_assert(static_cast<section_size_type>(got_pov - got_view) == got_size); 2435 2436 of->write_output_view(offset, oview_size, oview); 2437 of->write_output_view(got_file_offset, got_size, got_view); 2438 } 2439 2440 // Create the PLT section. 2441 2442 template<int size> 2443 void 2444 Target_x86_64<size>::make_plt_section(Symbol_table* symtab, Layout* layout) 2445 { 2446 if (this->plt_ == NULL) 2447 { 2448 // Create the GOT sections first. 2449 this->got_section(symtab, layout); 2450 2451 this->plt_ = this->make_data_plt(layout, this->got_, this->got_plt_, 2452 this->got_irelative_); 2453 2454 // Add unwind information if requested. 2455 if (parameters->options().ld_generated_unwind_info()) 2456 this->plt_->add_eh_frame(layout); 2457 2458 layout->add_output_section_data(".plt", elfcpp::SHT_PROGBITS, 2459 (elfcpp::SHF_ALLOC 2460 | elfcpp::SHF_EXECINSTR), 2461 this->plt_, ORDER_PLT, false); 2462 2463 // Make the sh_info field of .rela.plt point to .plt. 2464 Output_section* rela_plt_os = this->plt_->rela_plt()->output_section(); 2465 rela_plt_os->set_info_section(this->plt_->output_section()); 2466 } 2467 } 2468 2469 template<> 2470 Output_data_plt_x86_64<32>* 2471 Target_x86_64<32>::do_make_data_plt(Layout* layout, 2472 Output_data_got<64, false>* got, 2473 Output_data_got_plt_x86_64* got_plt, 2474 Output_data_space* got_irelative) 2475 { 2476 if (this->feature_1_ & elfcpp::GNU_PROPERTY_X86_FEATURE_1_IBT) 2477 return new Output_data_plt_x86_64_ibt<32>(layout, got, got_plt, 2478 got_irelative); 2479 return new Output_data_plt_x86_64_standard<32>(layout, got, got_plt, 2480 got_irelative); 2481 } 2482 2483 template<> 2484 Output_data_plt_x86_64<64>* 2485 Target_x86_64<64>::do_make_data_plt(Layout* layout, 2486 Output_data_got<64, false>* got, 2487 Output_data_got_plt_x86_64* got_plt, 2488 Output_data_space* got_irelative) 2489 { 2490 if (this->feature_1_ & elfcpp::GNU_PROPERTY_X86_FEATURE_1_IBT) 2491 return new Output_data_plt_x86_64_ibt<64>(layout, got, got_plt, 2492 got_irelative); 2493 else 2494 return new Output_data_plt_x86_64_standard<64>(layout, got, got_plt, 2495 got_irelative); 2496 } 2497 2498 template<> 2499 Output_data_plt_x86_64<32>* 2500 Target_x86_64<32>::do_make_data_plt(Layout* layout, 2501 Output_data_got<64, false>* got, 2502 Output_data_got_plt_x86_64* got_plt, 2503 Output_data_space* got_irelative, 2504 unsigned int plt_count) 2505 { 2506 if (this->feature_1_ & elfcpp::GNU_PROPERTY_X86_FEATURE_1_IBT) 2507 return new Output_data_plt_x86_64_ibt<32>(layout, got, got_plt, 2508 got_irelative, plt_count); 2509 return new Output_data_plt_x86_64_standard<32>(layout, got, got_plt, 2510 got_irelative, plt_count); 2511 } 2512 2513 template<> 2514 Output_data_plt_x86_64<64>* 2515 Target_x86_64<64>::do_make_data_plt(Layout* layout, 2516 Output_data_got<64, false>* got, 2517 Output_data_got_plt_x86_64* got_plt, 2518 Output_data_space* got_irelative, 2519 unsigned int plt_count) 2520 { 2521 if (this->feature_1_ & elfcpp::GNU_PROPERTY_X86_FEATURE_1_IBT) 2522 return new Output_data_plt_x86_64_ibt<64>(layout, got, got_plt, 2523 got_irelative, plt_count); 2524 else 2525 return new Output_data_plt_x86_64_standard<64>(layout, got, got_plt, 2526 got_irelative, 2527 plt_count); 2528 } 2529 2530 // Return the section for TLSDESC relocations. 2531 2532 template<int size> 2533 typename Target_x86_64<size>::Reloc_section* 2534 Target_x86_64<size>::rela_tlsdesc_section(Layout* layout) const 2535 { 2536 return this->plt_section()->rela_tlsdesc(layout); 2537 } 2538 2539 // Create a PLT entry for a global symbol. 2540 2541 template<int size> 2542 void 2543 Target_x86_64<size>::make_plt_entry(Symbol_table* symtab, Layout* layout, 2544 Symbol* gsym) 2545 { 2546 if (gsym->has_plt_offset()) 2547 return; 2548 2549 if (this->plt_ == NULL) 2550 this->make_plt_section(symtab, layout); 2551 2552 this->plt_->add_entry(symtab, layout, gsym); 2553 } 2554 2555 // Make a PLT entry for a local STT_GNU_IFUNC symbol. 2556 2557 template<int size> 2558 void 2559 Target_x86_64<size>::make_local_ifunc_plt_entry( 2560 Symbol_table* symtab, Layout* layout, 2561 Sized_relobj_file<size, false>* relobj, 2562 unsigned int local_sym_index) 2563 { 2564 if (relobj->local_has_plt_offset(local_sym_index)) 2565 return; 2566 if (this->plt_ == NULL) 2567 this->make_plt_section(symtab, layout); 2568 unsigned int plt_offset = this->plt_->add_local_ifunc_entry(symtab, layout, 2569 relobj, 2570 local_sym_index); 2571 relobj->set_local_plt_offset(local_sym_index, plt_offset); 2572 } 2573 2574 // Return the number of entries in the PLT. 2575 2576 template<int size> 2577 unsigned int 2578 Target_x86_64<size>::plt_entry_count() const 2579 { 2580 if (this->plt_ == NULL) 2581 return 0; 2582 return this->plt_->entry_count(); 2583 } 2584 2585 // Return the offset of the first non-reserved PLT entry. 2586 2587 template<int size> 2588 unsigned int 2589 Target_x86_64<size>::first_plt_entry_offset() const 2590 { 2591 if (this->plt_ == NULL) 2592 return 0; 2593 return this->plt_->first_plt_entry_offset(); 2594 } 2595 2596 // Return the size of each PLT entry. 2597 2598 template<int size> 2599 unsigned int 2600 Target_x86_64<size>::plt_entry_size() const 2601 { 2602 if (this->plt_ == NULL) 2603 return 0; 2604 return this->plt_->get_plt_entry_size(); 2605 } 2606 2607 // Create the GOT and PLT sections for an incremental update. 2608 2609 template<int size> 2610 Output_data_got_base* 2611 Target_x86_64<size>::init_got_plt_for_update(Symbol_table* symtab, 2612 Layout* layout, 2613 unsigned int got_count, 2614 unsigned int plt_count) 2615 { 2616 gold_assert(this->got_ == NULL); 2617 2618 this->got_ = new Output_data_got<64, false>(got_count * 8); 2619 layout->add_output_section_data(".got", elfcpp::SHT_PROGBITS, 2620 (elfcpp::SHF_ALLOC 2621 | elfcpp::SHF_WRITE), 2622 this->got_, ORDER_RELRO_LAST, 2623 true); 2624 2625 // Add the three reserved entries. 2626 this->got_plt_ = new Output_data_got_plt_x86_64(layout, (plt_count + 3) * 8); 2627 layout->add_output_section_data(".got.plt", elfcpp::SHT_PROGBITS, 2628 (elfcpp::SHF_ALLOC 2629 | elfcpp::SHF_WRITE), 2630 this->got_plt_, ORDER_NON_RELRO_FIRST, 2631 false); 2632 2633 // Define _GLOBAL_OFFSET_TABLE_ at the start of the PLT. 2634 this->global_offset_table_ = 2635 symtab->define_in_output_data("_GLOBAL_OFFSET_TABLE_", NULL, 2636 Symbol_table::PREDEFINED, 2637 this->got_plt_, 2638 0, 0, elfcpp::STT_OBJECT, 2639 elfcpp::STB_LOCAL, 2640 elfcpp::STV_HIDDEN, 0, 2641 false, false); 2642 2643 // If there are any TLSDESC relocations, they get GOT entries in 2644 // .got.plt after the jump slot entries. 2645 // FIXME: Get the count for TLSDESC entries. 2646 this->got_tlsdesc_ = new Output_data_got<64, false>(0); 2647 layout->add_output_section_data(".got.plt", elfcpp::SHT_PROGBITS, 2648 elfcpp::SHF_ALLOC | elfcpp::SHF_WRITE, 2649 this->got_tlsdesc_, 2650 ORDER_NON_RELRO_FIRST, false); 2651 2652 // If there are any IRELATIVE relocations, they get GOT entries in 2653 // .got.plt after the jump slot and TLSDESC entries. 2654 this->got_irelative_ = new Output_data_space(0, 8, "** GOT IRELATIVE PLT"); 2655 layout->add_output_section_data(".got.plt", elfcpp::SHT_PROGBITS, 2656 elfcpp::SHF_ALLOC | elfcpp::SHF_WRITE, 2657 this->got_irelative_, 2658 ORDER_NON_RELRO_FIRST, false); 2659 2660 // Create the PLT section. 2661 this->plt_ = this->make_data_plt(layout, this->got_, 2662 this->got_plt_, 2663 this->got_irelative_, 2664 plt_count); 2665 2666 // Add unwind information if requested. 2667 if (parameters->options().ld_generated_unwind_info()) 2668 this->plt_->add_eh_frame(layout); 2669 2670 layout->add_output_section_data(".plt", elfcpp::SHT_PROGBITS, 2671 elfcpp::SHF_ALLOC | elfcpp::SHF_EXECINSTR, 2672 this->plt_, ORDER_PLT, false); 2673 2674 // Make the sh_info field of .rela.plt point to .plt. 2675 Output_section* rela_plt_os = this->plt_->rela_plt()->output_section(); 2676 rela_plt_os->set_info_section(this->plt_->output_section()); 2677 2678 // Create the rela_dyn section. 2679 this->rela_dyn_section(layout); 2680 2681 return this->got_; 2682 } 2683 2684 // Reserve a GOT entry for a local symbol, and regenerate any 2685 // necessary dynamic relocations. 2686 2687 template<int size> 2688 void 2689 Target_x86_64<size>::reserve_local_got_entry( 2690 unsigned int got_index, 2691 Sized_relobj<size, false>* obj, 2692 unsigned int r_sym, 2693 unsigned int got_type) 2694 { 2695 unsigned int got_offset = got_index * 8; 2696 Reloc_section* rela_dyn = this->rela_dyn_section(NULL); 2697 2698 this->got_->reserve_local(got_index, obj, r_sym, got_type); 2699 switch (got_type) 2700 { 2701 case GOT_TYPE_STANDARD: 2702 if (parameters->options().output_is_position_independent()) 2703 rela_dyn->add_local_relative(obj, r_sym, elfcpp::R_X86_64_RELATIVE, 2704 this->got_, got_offset, 0, false); 2705 break; 2706 case GOT_TYPE_TLS_OFFSET: 2707 rela_dyn->add_local(obj, r_sym, elfcpp::R_X86_64_TPOFF64, 2708 this->got_, got_offset, 0); 2709 break; 2710 case GOT_TYPE_TLS_PAIR: 2711 this->got_->reserve_slot(got_index + 1); 2712 rela_dyn->add_local(obj, r_sym, elfcpp::R_X86_64_DTPMOD64, 2713 this->got_, got_offset, 0); 2714 break; 2715 case GOT_TYPE_TLS_DESC: 2716 gold_fatal(_("TLS_DESC not yet supported for incremental linking")); 2717 // this->got_->reserve_slot(got_index + 1); 2718 // rela_dyn->add_target_specific(elfcpp::R_X86_64_TLSDESC, arg, 2719 // this->got_, got_offset, 0); 2720 break; 2721 default: 2722 gold_unreachable(); 2723 } 2724 } 2725 2726 // Reserve a GOT entry for a global symbol, and regenerate any 2727 // necessary dynamic relocations. 2728 2729 template<int size> 2730 void 2731 Target_x86_64<size>::reserve_global_got_entry(unsigned int got_index, 2732 Symbol* gsym, 2733 unsigned int got_type) 2734 { 2735 unsigned int got_offset = got_index * 8; 2736 Reloc_section* rela_dyn = this->rela_dyn_section(NULL); 2737 2738 this->got_->reserve_global(got_index, gsym, got_type); 2739 switch (got_type) 2740 { 2741 case GOT_TYPE_STANDARD: 2742 if (!gsym->final_value_is_known()) 2743 { 2744 if (gsym->is_from_dynobj() 2745 || gsym->is_undefined() 2746 || gsym->is_preemptible() 2747 || gsym->type() == elfcpp::STT_GNU_IFUNC) 2748 rela_dyn->add_global(gsym, elfcpp::R_X86_64_GLOB_DAT, 2749 this->got_, got_offset, 0); 2750 else 2751 rela_dyn->add_global_relative(gsym, elfcpp::R_X86_64_RELATIVE, 2752 this->got_, got_offset, 0, false); 2753 } 2754 break; 2755 case GOT_TYPE_TLS_OFFSET: 2756 rela_dyn->add_global_relative(gsym, elfcpp::R_X86_64_TPOFF64, 2757 this->got_, got_offset, 0, false); 2758 break; 2759 case GOT_TYPE_TLS_PAIR: 2760 this->got_->reserve_slot(got_index + 1); 2761 rela_dyn->add_global_relative(gsym, elfcpp::R_X86_64_DTPMOD64, 2762 this->got_, got_offset, 0, false); 2763 rela_dyn->add_global_relative(gsym, elfcpp::R_X86_64_DTPOFF64, 2764 this->got_, got_offset + 8, 0, false); 2765 break; 2766 case GOT_TYPE_TLS_DESC: 2767 this->got_->reserve_slot(got_index + 1); 2768 rela_dyn->add_global_relative(gsym, elfcpp::R_X86_64_TLSDESC, 2769 this->got_, got_offset, 0, false); 2770 break; 2771 default: 2772 gold_unreachable(); 2773 } 2774 } 2775 2776 // Register an existing PLT entry for a global symbol. 2777 2778 template<int size> 2779 void 2780 Target_x86_64<size>::register_global_plt_entry(Symbol_table* symtab, 2781 Layout* layout, 2782 unsigned int plt_index, 2783 Symbol* gsym) 2784 { 2785 gold_assert(this->plt_ != NULL); 2786 gold_assert(!gsym->has_plt_offset()); 2787 2788 this->plt_->reserve_slot(plt_index); 2789 2790 gsym->set_plt_offset((plt_index + 1) * this->plt_entry_size()); 2791 2792 unsigned int got_offset = (plt_index + 3) * 8; 2793 this->plt_->add_relocation(symtab, layout, gsym, got_offset); 2794 } 2795 2796 // Force a COPY relocation for a given symbol. 2797 2798 template<int size> 2799 void 2800 Target_x86_64<size>::emit_copy_reloc( 2801 Symbol_table* symtab, Symbol* sym, Output_section* os, off_t offset) 2802 { 2803 this->copy_relocs_.emit_copy_reloc(symtab, 2804 symtab->get_sized_symbol<size>(sym), 2805 os, 2806 offset, 2807 this->rela_dyn_section(NULL)); 2808 } 2809 2810 // Define the _TLS_MODULE_BASE_ symbol in the TLS segment. 2811 2812 template<int size> 2813 void 2814 Target_x86_64<size>::define_tls_base_symbol(Symbol_table* symtab, 2815 Layout* layout) 2816 { 2817 if (this->tls_base_symbol_defined_) 2818 return; 2819 2820 Output_segment* tls_segment = layout->tls_segment(); 2821 if (tls_segment != NULL) 2822 { 2823 bool is_exec = parameters->options().output_is_executable(); 2824 symtab->define_in_output_segment("_TLS_MODULE_BASE_", NULL, 2825 Symbol_table::PREDEFINED, 2826 tls_segment, 0, 0, 2827 elfcpp::STT_TLS, 2828 elfcpp::STB_LOCAL, 2829 elfcpp::STV_HIDDEN, 0, 2830 (is_exec 2831 ? Symbol::SEGMENT_END 2832 : Symbol::SEGMENT_START), 2833 true); 2834 } 2835 this->tls_base_symbol_defined_ = true; 2836 } 2837 2838 // Create the reserved PLT and GOT entries for the TLS descriptor resolver. 2839 2840 template<int size> 2841 void 2842 Target_x86_64<size>::reserve_tlsdesc_entries(Symbol_table* symtab, 2843 Layout* layout) 2844 { 2845 if (this->plt_ == NULL) 2846 this->make_plt_section(symtab, layout); 2847 2848 if (!this->plt_->has_tlsdesc_entry()) 2849 { 2850 // Allocate the TLSDESC_GOT entry. 2851 Output_data_got<64, false>* got = this->got_section(symtab, layout); 2852 unsigned int got_offset = got->add_constant(0); 2853 2854 // Allocate the TLSDESC_PLT entry. 2855 this->plt_->reserve_tlsdesc_entry(got_offset); 2856 } 2857 } 2858 2859 // Create a GOT entry for the TLS module index. 2860 2861 template<int size> 2862 unsigned int 2863 Target_x86_64<size>::got_mod_index_entry(Symbol_table* symtab, Layout* layout, 2864 Sized_relobj_file<size, false>* object) 2865 { 2866 if (this->got_mod_index_offset_ == -1U) 2867 { 2868 gold_assert(symtab != NULL && layout != NULL && object != NULL); 2869 Reloc_section* rela_dyn = this->rela_dyn_section(layout); 2870 Output_data_got<64, false>* got = this->got_section(symtab, layout); 2871 unsigned int got_offset = got->add_constant(0); 2872 rela_dyn->add_local(object, 0, elfcpp::R_X86_64_DTPMOD64, got, 2873 got_offset, 0); 2874 got->add_constant(0); 2875 this->got_mod_index_offset_ = got_offset; 2876 } 2877 return this->got_mod_index_offset_; 2878 } 2879 2880 // Optimize the TLS relocation type based on what we know about the 2881 // symbol. IS_FINAL is true if the final address of this symbol is 2882 // known at link time. RELOC_VIEW points to the relocation offset. 2883 2884 template<int size> 2885 tls::Tls_optimization 2886 Target_x86_64<size>::optimize_tls_reloc(bool is_final, int r_type, 2887 size_t r_offset, 2888 const unsigned char* reloc_view) 2889 { 2890 // If we are generating a shared library, then we can't do anything 2891 // in the linker. 2892 if (parameters->options().shared()) 2893 return tls::TLSOPT_NONE; 2894 2895 switch (r_type) 2896 { 2897 case elfcpp::R_X86_64_CODE_4_GOTPC32_TLSDESC: 2898 if (r_offset <= 4 || *(reloc_view - 4) != 0xd5) 2899 return tls::TLSOPT_NONE; 2900 // Fall through. 2901 case elfcpp::R_X86_64_TLSGD: 2902 case elfcpp::R_X86_64_GOTPC32_TLSDESC: 2903 case elfcpp::R_X86_64_TLSDESC_CALL: 2904 // These are General-Dynamic which permits fully general TLS 2905 // access. Since we know that we are generating an executable, 2906 // we can convert this to Initial-Exec. If we also know that 2907 // this is a local symbol, we can further switch to Local-Exec. 2908 if (is_final) 2909 return tls::TLSOPT_TO_LE; 2910 return tls::TLSOPT_TO_IE; 2911 2912 case elfcpp::R_X86_64_TLSLD: 2913 // This is Local-Dynamic, which refers to a local symbol in the 2914 // dynamic TLS block. Since we know that we generating an 2915 // executable, we can switch to Local-Exec. 2916 return tls::TLSOPT_TO_LE; 2917 2918 case elfcpp::R_X86_64_DTPOFF32: 2919 case elfcpp::R_X86_64_DTPOFF64: 2920 // Another Local-Dynamic reloc. 2921 return tls::TLSOPT_TO_LE; 2922 2923 case elfcpp::R_X86_64_CODE_4_GOTTPOFF: 2924 if (r_offset <= 4 || *(reloc_view - 4) != 0xd5) 2925 return tls::TLSOPT_NONE; 2926 // Fall through. 2927 case elfcpp::R_X86_64_GOTTPOFF: 2928 // These are Initial-Exec relocs which get the thread offset 2929 // from the GOT. If we know that we are linking against the 2930 // local symbol, we can switch to Local-Exec, which links the 2931 // thread offset into the instruction. 2932 if (is_final) 2933 return tls::TLSOPT_TO_LE; 2934 return tls::TLSOPT_NONE; 2935 2936 case elfcpp::R_X86_64_TPOFF32: 2937 // When we already have Local-Exec, there is nothing further we 2938 // can do. 2939 return tls::TLSOPT_NONE; 2940 2941 default: 2942 gold_unreachable(); 2943 } 2944 } 2945 2946 // Get the Reference_flags for a particular relocation. 2947 2948 template<int size> 2949 int 2950 Target_x86_64<size>::Scan::get_reference_flags(unsigned int r_type) 2951 { 2952 switch (r_type) 2953 { 2954 case elfcpp::R_X86_64_NONE: 2955 case elfcpp::R_X86_64_GNU_VTINHERIT: 2956 case elfcpp::R_X86_64_GNU_VTENTRY: 2957 case elfcpp::R_X86_64_GOTPC32: 2958 case elfcpp::R_X86_64_GOTPC64: 2959 // No symbol reference. 2960 return 0; 2961 2962 case elfcpp::R_X86_64_64: 2963 case elfcpp::R_X86_64_32: 2964 case elfcpp::R_X86_64_32S: 2965 case elfcpp::R_X86_64_16: 2966 case elfcpp::R_X86_64_8: 2967 return Symbol::ABSOLUTE_REF; 2968 2969 case elfcpp::R_X86_64_PC64: 2970 case elfcpp::R_X86_64_PC32: 2971 case elfcpp::R_X86_64_PC16: 2972 case elfcpp::R_X86_64_PC8: 2973 case elfcpp::R_X86_64_GOTOFF64: 2974 return Symbol::RELATIVE_REF; 2975 2976 case elfcpp::R_X86_64_PLT32: 2977 case elfcpp::R_X86_64_PLTOFF64: 2978 return Symbol::FUNCTION_CALL | Symbol::RELATIVE_REF; 2979 2980 case elfcpp::R_X86_64_GOT64: 2981 case elfcpp::R_X86_64_GOT32: 2982 case elfcpp::R_X86_64_GOTPCREL64: 2983 case elfcpp::R_X86_64_GOTPCREL: 2984 case elfcpp::R_X86_64_GOTPCRELX: 2985 case elfcpp::R_X86_64_REX_GOTPCRELX: 2986 case elfcpp::R_X86_64_CODE_4_GOTPCRELX: 2987 case elfcpp::R_X86_64_GOTPLT64: 2988 // Absolute in GOT. 2989 return Symbol::ABSOLUTE_REF; 2990 2991 case elfcpp::R_X86_64_TLSGD: // Global-dynamic 2992 case elfcpp::R_X86_64_GOTPC32_TLSDESC: // Global-dynamic (from ~oliva url) 2993 case elfcpp::R_X86_64_CODE_4_GOTPC32_TLSDESC: 2994 case elfcpp::R_X86_64_TLSDESC_CALL: 2995 case elfcpp::R_X86_64_TLSLD: // Local-dynamic 2996 case elfcpp::R_X86_64_DTPOFF32: 2997 case elfcpp::R_X86_64_DTPOFF64: 2998 case elfcpp::R_X86_64_GOTTPOFF: // Initial-exec 2999 case elfcpp::R_X86_64_CODE_4_GOTTPOFF: 3000 case elfcpp::R_X86_64_TPOFF32: // Local-exec 3001 return Symbol::TLS_REF; 3002 3003 case elfcpp::R_X86_64_COPY: 3004 case elfcpp::R_X86_64_GLOB_DAT: 3005 case elfcpp::R_X86_64_JUMP_SLOT: 3006 case elfcpp::R_X86_64_RELATIVE: 3007 case elfcpp::R_X86_64_IRELATIVE: 3008 case elfcpp::R_X86_64_TPOFF64: 3009 case elfcpp::R_X86_64_DTPMOD64: 3010 case elfcpp::R_X86_64_TLSDESC: 3011 case elfcpp::R_X86_64_SIZE32: 3012 case elfcpp::R_X86_64_SIZE64: 3013 default: 3014 // Not expected. We will give an error later. 3015 return 0; 3016 } 3017 } 3018 3019 // Report an unsupported relocation against a local symbol. 3020 3021 template<int size> 3022 void 3023 Target_x86_64<size>::Scan::unsupported_reloc_local( 3024 Sized_relobj_file<size, false>* object, 3025 unsigned int r_type) 3026 { 3027 gold_error(_("%s: unsupported reloc %u against local symbol"), 3028 object->name().c_str(), r_type); 3029 } 3030 3031 // We are about to emit a dynamic relocation of type R_TYPE. If the 3032 // dynamic linker does not support it, issue an error. The GNU linker 3033 // only issues a non-PIC error for an allocated read-only section. 3034 // Here we know the section is allocated, but we don't know that it is 3035 // read-only. But we check for all the relocation types which the 3036 // glibc dynamic linker supports, so it seems appropriate to issue an 3037 // error even if the section is not read-only. If GSYM is not NULL, 3038 // it is the symbol the relocation is against; if it is NULL, the 3039 // relocation is against a local symbol. 3040 3041 template<int size> 3042 void 3043 Target_x86_64<size>::Scan::check_non_pic(Relobj* object, unsigned int r_type, 3044 Symbol* gsym) 3045 { 3046 switch (r_type) 3047 { 3048 // These are the relocation types supported by glibc for x86_64 3049 // which should always work. 3050 case elfcpp::R_X86_64_RELATIVE: 3051 case elfcpp::R_X86_64_IRELATIVE: 3052 case elfcpp::R_X86_64_GLOB_DAT: 3053 case elfcpp::R_X86_64_JUMP_SLOT: 3054 case elfcpp::R_X86_64_DTPMOD64: 3055 case elfcpp::R_X86_64_DTPOFF64: 3056 case elfcpp::R_X86_64_TPOFF64: 3057 case elfcpp::R_X86_64_64: 3058 case elfcpp::R_X86_64_COPY: 3059 return; 3060 3061 // glibc supports these reloc types, but they can overflow. 3062 case elfcpp::R_X86_64_PC32: 3063 // A PC relative reference is OK against a local symbol or if 3064 // the symbol is defined locally. 3065 if (gsym == NULL 3066 || (!gsym->is_from_dynobj() 3067 && !gsym->is_undefined() 3068 && !gsym->is_preemptible())) 3069 return; 3070 // Fall through. 3071 case elfcpp::R_X86_64_32: 3072 // R_X86_64_32 is OK for x32. 3073 if (size == 32 && r_type == elfcpp::R_X86_64_32) 3074 return; 3075 if (this->issued_non_pic_error_) 3076 return; 3077 gold_assert(parameters->options().output_is_position_independent()); 3078 if (gsym == NULL) 3079 object->error(_("requires dynamic R_X86_64_32 reloc which may " 3080 "overflow at runtime; recompile with -fPIC")); 3081 else 3082 { 3083 const char *r_name; 3084 switch (r_type) 3085 { 3086 case elfcpp::R_X86_64_32: 3087 r_name = "R_X86_64_32"; 3088 break; 3089 case elfcpp::R_X86_64_PC32: 3090 r_name = "R_X86_64_PC32"; 3091 break; 3092 default: 3093 gold_unreachable(); 3094 break; 3095 } 3096 object->error(_("requires dynamic %s reloc against '%s' " 3097 "which may overflow at runtime; recompile " 3098 "with -fPIC"), 3099 r_name, gsym->name()); 3100 } 3101 this->issued_non_pic_error_ = true; 3102 return; 3103 3104 default: 3105 // This prevents us from issuing more than one error per reloc 3106 // section. But we can still wind up issuing more than one 3107 // error per object file. 3108 if (this->issued_non_pic_error_) 3109 return; 3110 gold_assert(parameters->options().output_is_position_independent()); 3111 object->error(_("requires unsupported dynamic reloc %u; " 3112 "recompile with -fPIC"), 3113 r_type); 3114 this->issued_non_pic_error_ = true; 3115 return; 3116 3117 case elfcpp::R_X86_64_NONE: 3118 gold_unreachable(); 3119 } 3120 } 3121 3122 // Return whether we need to make a PLT entry for a relocation of the 3123 // given type against a STT_GNU_IFUNC symbol. 3124 3125 template<int size> 3126 bool 3127 Target_x86_64<size>::Scan::reloc_needs_plt_for_ifunc( 3128 Sized_relobj_file<size, false>* object, 3129 unsigned int r_type) 3130 { 3131 int flags = Scan::get_reference_flags(r_type); 3132 if (flags & Symbol::TLS_REF) 3133 gold_error(_("%s: unsupported TLS reloc %u for IFUNC symbol"), 3134 object->name().c_str(), r_type); 3135 return flags != 0; 3136 } 3137 3138 // Scan a relocation for a local symbol. 3139 3140 template<int size> 3141 inline void 3142 Target_x86_64<size>::Scan::local(Symbol_table* symtab, 3143 Layout* layout, 3144 Target_x86_64<size>* target, 3145 Sized_relobj_file<size, false>* object, 3146 unsigned int data_shndx, 3147 Output_section* output_section, 3148 const elfcpp::Rela<size, false>& reloc, 3149 unsigned int r_type, 3150 const elfcpp::Sym<size, false>& lsym, 3151 bool is_discarded) 3152 { 3153 if (is_discarded) 3154 return; 3155 3156 // A local STT_GNU_IFUNC symbol may require a PLT entry. 3157 bool is_ifunc = lsym.get_st_type() == elfcpp::STT_GNU_IFUNC; 3158 if (is_ifunc && this->reloc_needs_plt_for_ifunc(object, r_type)) 3159 { 3160 unsigned int r_sym = elfcpp::elf_r_sym<size>(reloc.get_r_info()); 3161 target->make_local_ifunc_plt_entry(symtab, layout, object, r_sym); 3162 } 3163 3164 const unsigned char* reloc_view = NULL; 3165 3166 switch (r_type) 3167 { 3168 case elfcpp::R_X86_64_NONE: 3169 case elfcpp::R_X86_64_GNU_VTINHERIT: 3170 case elfcpp::R_X86_64_GNU_VTENTRY: 3171 break; 3172 3173 case elfcpp::R_X86_64_64: 3174 // If building a shared library (or a position-independent 3175 // executable), we need to create a dynamic relocation for this 3176 // location. The relocation applied at link time will apply the 3177 // link-time value, so we flag the location with an 3178 // R_X86_64_RELATIVE relocation so the dynamic loader can 3179 // relocate it easily. 3180 if (parameters->options().output_is_position_independent()) 3181 { 3182 unsigned int r_sym = elfcpp::elf_r_sym<size>(reloc.get_r_info()); 3183 Reloc_section* rela_dyn = target->rela_dyn_section(layout); 3184 rela_dyn->add_local_relative(object, r_sym, 3185 (size == 32 3186 ? elfcpp::R_X86_64_RELATIVE64 3187 : elfcpp::R_X86_64_RELATIVE), 3188 output_section, data_shndx, 3189 reloc.get_r_offset(), 3190 reloc.get_r_addend(), is_ifunc); 3191 } 3192 break; 3193 3194 case elfcpp::R_X86_64_32: 3195 case elfcpp::R_X86_64_32S: 3196 case elfcpp::R_X86_64_16: 3197 case elfcpp::R_X86_64_8: 3198 // If building a shared library (or a position-independent 3199 // executable), we need to create a dynamic relocation for this 3200 // location. We can't use an R_X86_64_RELATIVE relocation 3201 // because that is always a 64-bit relocation. 3202 if (parameters->options().output_is_position_independent()) 3203 { 3204 // Use R_X86_64_RELATIVE relocation for R_X86_64_32 under x32. 3205 if (size == 32 && r_type == elfcpp::R_X86_64_32) 3206 { 3207 unsigned int r_sym = elfcpp::elf_r_sym<size>(reloc.get_r_info()); 3208 Reloc_section* rela_dyn = target->rela_dyn_section(layout); 3209 rela_dyn->add_local_relative(object, r_sym, 3210 elfcpp::R_X86_64_RELATIVE, 3211 output_section, data_shndx, 3212 reloc.get_r_offset(), 3213 reloc.get_r_addend(), is_ifunc); 3214 break; 3215 } 3216 3217 this->check_non_pic(object, r_type, NULL); 3218 3219 Reloc_section* rela_dyn = target->rela_dyn_section(layout); 3220 unsigned int r_sym = elfcpp::elf_r_sym<size>(reloc.get_r_info()); 3221 if (lsym.get_st_type() != elfcpp::STT_SECTION) 3222 rela_dyn->add_local(object, r_sym, r_type, output_section, 3223 data_shndx, reloc.get_r_offset(), 3224 reloc.get_r_addend()); 3225 else 3226 { 3227 gold_assert(lsym.get_st_value() == 0); 3228 unsigned int shndx = lsym.get_st_shndx(); 3229 bool is_ordinary; 3230 shndx = object->adjust_sym_shndx(r_sym, shndx, 3231 &is_ordinary); 3232 if (!is_ordinary) 3233 object->error(_("section symbol %u has bad shndx %u"), 3234 r_sym, shndx); 3235 else 3236 rela_dyn->add_local_section(object, shndx, 3237 r_type, output_section, 3238 data_shndx, reloc.get_r_offset(), 3239 reloc.get_r_addend()); 3240 } 3241 } 3242 break; 3243 3244 case elfcpp::R_X86_64_PC64: 3245 case elfcpp::R_X86_64_PC32: 3246 case elfcpp::R_X86_64_PC16: 3247 case elfcpp::R_X86_64_PC8: 3248 break; 3249 3250 case elfcpp::R_X86_64_PLT32: 3251 // Since we know this is a local symbol, we can handle this as a 3252 // PC32 reloc. 3253 break; 3254 3255 case elfcpp::R_X86_64_GOTPC32: 3256 case elfcpp::R_X86_64_GOTOFF64: 3257 case elfcpp::R_X86_64_GOTPC64: 3258 case elfcpp::R_X86_64_PLTOFF64: 3259 // We need a GOT section. 3260 target->got_section(symtab, layout); 3261 // For PLTOFF64, we'd normally want a PLT section, but since we 3262 // know this is a local symbol, no PLT is needed. 3263 break; 3264 3265 case elfcpp::R_X86_64_GOT64: 3266 case elfcpp::R_X86_64_GOT32: 3267 case elfcpp::R_X86_64_GOTPCREL64: 3268 case elfcpp::R_X86_64_GOTPCREL: 3269 case elfcpp::R_X86_64_GOTPCRELX: 3270 case elfcpp::R_X86_64_REX_GOTPCRELX: 3271 case elfcpp::R_X86_64_CODE_4_GOTPCRELX: 3272 case elfcpp::R_X86_64_GOTPLT64: 3273 { 3274 // The symbol requires a GOT section. 3275 Output_data_got<64, false>* got = target->got_section(symtab, layout); 3276 3277 // If the relocation symbol isn't IFUNC, 3278 // and is local, then we will convert 3279 // mov foo@GOTPCREL(%rip), %reg 3280 // to lea foo(%rip), %reg. 3281 // in Relocate::relocate. 3282 size_t r_offset = reloc.get_r_offset(); 3283 if (!parameters->incremental() 3284 && (((r_type == elfcpp::R_X86_64_GOTPCREL 3285 || r_type == elfcpp::R_X86_64_GOTPCRELX 3286 || r_type == elfcpp::R_X86_64_REX_GOTPCRELX) 3287 && r_offset >= 2) 3288 || (r_type == elfcpp::R_X86_64_CODE_4_GOTPCRELX 3289 && r_offset >= 4)) 3290 && reloc.get_r_addend() == -4 3291 && !is_ifunc) 3292 { 3293 section_size_type stype; 3294 const unsigned char* view = object->section_contents(data_shndx, 3295 &stype, true); 3296 if (r_type == elfcpp::R_X86_64_CODE_4_GOTPCRELX 3297 && view[r_offset - 4] != 0xd5) 3298 goto need_got; 3299 3300 if (view[r_offset - 2] == 0x8b) 3301 break; 3302 } 3303 3304 need_got: 3305 3306 // The symbol requires a GOT entry. 3307 unsigned int r_sym = elfcpp::elf_r_sym<size>(reloc.get_r_info()); 3308 3309 // For a STT_GNU_IFUNC symbol we want the PLT offset. That 3310 // lets function pointers compare correctly with shared 3311 // libraries. Otherwise we would need an IRELATIVE reloc. 3312 bool is_new; 3313 if (is_ifunc) 3314 is_new = got->add_local_plt(object, r_sym, GOT_TYPE_STANDARD); 3315 else 3316 is_new = got->add_local(object, r_sym, GOT_TYPE_STANDARD); 3317 if (is_new) 3318 { 3319 // If we are generating a shared object, we need to add a 3320 // dynamic relocation for this symbol's GOT entry. 3321 if (parameters->options().output_is_position_independent()) 3322 { 3323 Reloc_section* rela_dyn = target->rela_dyn_section(layout); 3324 // R_X86_64_RELATIVE assumes a 64-bit relocation. 3325 if (r_type != elfcpp::R_X86_64_GOT32) 3326 { 3327 unsigned int got_offset = 3328 object->local_got_offset(r_sym, GOT_TYPE_STANDARD); 3329 rela_dyn->add_local_relative(object, r_sym, 3330 elfcpp::R_X86_64_RELATIVE, 3331 got, got_offset, 0, is_ifunc); 3332 } 3333 else 3334 { 3335 this->check_non_pic(object, r_type, NULL); 3336 3337 gold_assert(lsym.get_st_type() != elfcpp::STT_SECTION); 3338 rela_dyn->add_local( 3339 object, r_sym, r_type, got, 3340 object->local_got_offset(r_sym, GOT_TYPE_STANDARD), 0); 3341 } 3342 } 3343 } 3344 // For GOTPLT64, we'd normally want a PLT section, but since 3345 // we know this is a local symbol, no PLT is needed. 3346 } 3347 break; 3348 3349 case elfcpp::R_X86_64_COPY: 3350 case elfcpp::R_X86_64_GLOB_DAT: 3351 case elfcpp::R_X86_64_JUMP_SLOT: 3352 case elfcpp::R_X86_64_RELATIVE: 3353 case elfcpp::R_X86_64_IRELATIVE: 3354 // These are outstanding tls relocs, which are unexpected when linking 3355 case elfcpp::R_X86_64_TPOFF64: 3356 case elfcpp::R_X86_64_DTPMOD64: 3357 case elfcpp::R_X86_64_TLSDESC: 3358 gold_error(_("%s: unexpected reloc %u in object file"), 3359 object->name().c_str(), r_type); 3360 break; 3361 3362 // These are initial tls relocs, which are expected when linking 3363 case elfcpp::R_X86_64_CODE_4_GOTPC32_TLSDESC: 3364 case elfcpp::R_X86_64_CODE_4_GOTTPOFF: 3365 { 3366 section_size_type stype; 3367 reloc_view = object->section_contents(data_shndx, &stype, true); 3368 } 3369 // Fall through. 3370 case elfcpp::R_X86_64_TLSGD: // Global-dynamic 3371 case elfcpp::R_X86_64_GOTPC32_TLSDESC: // Global-dynamic (from ~oliva url) 3372 case elfcpp::R_X86_64_TLSDESC_CALL: 3373 case elfcpp::R_X86_64_TLSLD: // Local-dynamic 3374 case elfcpp::R_X86_64_DTPOFF32: 3375 case elfcpp::R_X86_64_DTPOFF64: 3376 case elfcpp::R_X86_64_GOTTPOFF: // Initial-exec 3377 case elfcpp::R_X86_64_TPOFF32: // Local-exec 3378 { 3379 bool output_is_shared = parameters->options().shared(); 3380 size_t r_offset = reloc.get_r_offset(); 3381 const tls::Tls_optimization optimized_type 3382 = Target_x86_64<size>::optimize_tls_reloc(!output_is_shared, 3383 r_type, r_offset, 3384 reloc_view + r_offset); 3385 switch (r_type) 3386 { 3387 case elfcpp::R_X86_64_TLSGD: // General-dynamic 3388 if (optimized_type == tls::TLSOPT_NONE) 3389 { 3390 // Create a pair of GOT entries for the module index and 3391 // dtv-relative offset. 3392 Output_data_got<64, false>* got 3393 = target->got_section(symtab, layout); 3394 unsigned int r_sym = elfcpp::elf_r_sym<size>(reloc.get_r_info()); 3395 unsigned int shndx = lsym.get_st_shndx(); 3396 bool is_ordinary; 3397 shndx = object->adjust_sym_shndx(r_sym, shndx, &is_ordinary); 3398 if (!is_ordinary) 3399 object->error(_("local symbol %u has bad shndx %u"), 3400 r_sym, shndx); 3401 else 3402 got->add_local_pair_with_rel(object, r_sym, 3403 shndx, 3404 GOT_TYPE_TLS_PAIR, 3405 target->rela_dyn_section(layout), 3406 elfcpp::R_X86_64_DTPMOD64); 3407 } 3408 else if (optimized_type != tls::TLSOPT_TO_LE) 3409 unsupported_reloc_local(object, r_type); 3410 break; 3411 3412 case elfcpp::R_X86_64_GOTPC32_TLSDESC: 3413 case elfcpp::R_X86_64_CODE_4_GOTPC32_TLSDESC: 3414 target->define_tls_base_symbol(symtab, layout); 3415 if (optimized_type == tls::TLSOPT_NONE) 3416 { 3417 // Create reserved PLT and GOT entries for the resolver. 3418 target->reserve_tlsdesc_entries(symtab, layout); 3419 3420 // Generate a double GOT entry with an 3421 // R_X86_64_TLSDESC reloc. The R_X86_64_TLSDESC reloc 3422 // is resolved lazily, so the GOT entry needs to be in 3423 // an area in .got.plt, not .got. Call got_section to 3424 // make sure the section has been created. 3425 target->got_section(symtab, layout); 3426 Output_data_got<64, false>* got = target->got_tlsdesc_section(); 3427 unsigned int r_sym = elfcpp::elf_r_sym<size>(reloc.get_r_info()); 3428 if (!object->local_has_got_offset(r_sym, GOT_TYPE_TLS_DESC)) 3429 { 3430 unsigned int got_offset = got->add_constant(0); 3431 got->add_constant(0); 3432 object->set_local_got_offset(r_sym, GOT_TYPE_TLS_DESC, 3433 got_offset); 3434 Reloc_section* rt = target->rela_tlsdesc_section(layout); 3435 // We store the arguments we need in a vector, and 3436 // use the index into the vector as the parameter 3437 // to pass to the target specific routines. 3438 uintptr_t intarg = target->add_tlsdesc_info(object, r_sym); 3439 void* arg = reinterpret_cast<void*>(intarg); 3440 rt->add_target_specific(elfcpp::R_X86_64_TLSDESC, arg, 3441 got, got_offset, 0); 3442 } 3443 } 3444 else if (optimized_type != tls::TLSOPT_TO_LE) 3445 unsupported_reloc_local(object, r_type); 3446 break; 3447 3448 case elfcpp::R_X86_64_TLSDESC_CALL: 3449 break; 3450 3451 case elfcpp::R_X86_64_TLSLD: // Local-dynamic 3452 if (optimized_type == tls::TLSOPT_NONE) 3453 { 3454 // Create a GOT entry for the module index. 3455 target->got_mod_index_entry(symtab, layout, object); 3456 } 3457 else if (optimized_type != tls::TLSOPT_TO_LE) 3458 unsupported_reloc_local(object, r_type); 3459 break; 3460 3461 case elfcpp::R_X86_64_DTPOFF32: 3462 case elfcpp::R_X86_64_DTPOFF64: 3463 break; 3464 3465 case elfcpp::R_X86_64_GOTTPOFF: // Initial-exec 3466 case elfcpp::R_X86_64_CODE_4_GOTTPOFF: 3467 layout->set_has_static_tls(); 3468 if (optimized_type == tls::TLSOPT_NONE) 3469 { 3470 // Create a GOT entry for the tp-relative offset. 3471 Output_data_got<64, false>* got 3472 = target->got_section(symtab, layout); 3473 unsigned int r_sym = elfcpp::elf_r_sym<size>(reloc.get_r_info()); 3474 got->add_local_with_rel(object, r_sym, GOT_TYPE_TLS_OFFSET, 3475 target->rela_dyn_section(layout), 3476 elfcpp::R_X86_64_TPOFF64); 3477 } 3478 else if (optimized_type != tls::TLSOPT_TO_LE) 3479 unsupported_reloc_local(object, r_type); 3480 break; 3481 3482 case elfcpp::R_X86_64_TPOFF32: // Local-exec 3483 layout->set_has_static_tls(); 3484 if (output_is_shared) 3485 unsupported_reloc_local(object, r_type); 3486 break; 3487 3488 default: 3489 gold_unreachable(); 3490 } 3491 } 3492 break; 3493 3494 case elfcpp::R_X86_64_SIZE32: 3495 case elfcpp::R_X86_64_SIZE64: 3496 default: 3497 gold_error(_("%s: unsupported reloc %u against local symbol"), 3498 object->name().c_str(), r_type); 3499 break; 3500 } 3501 } 3502 3503 3504 // Report an unsupported relocation against a global symbol. 3505 3506 template<int size> 3507 void 3508 Target_x86_64<size>::Scan::unsupported_reloc_global( 3509 Sized_relobj_file<size, false>* object, 3510 unsigned int r_type, 3511 Symbol* gsym) 3512 { 3513 gold_error(_("%s: unsupported reloc %u against global symbol %s"), 3514 object->name().c_str(), r_type, gsym->demangled_name().c_str()); 3515 } 3516 3517 // Returns true if this relocation type could be that of a function pointer. 3518 template<int size> 3519 inline bool 3520 Target_x86_64<size>::Scan::possible_function_pointer_reloc( 3521 Sized_relobj_file<size, false>* src_obj, 3522 unsigned int src_indx, 3523 unsigned int r_offset, 3524 unsigned int r_type) 3525 { 3526 switch (r_type) 3527 { 3528 case elfcpp::R_X86_64_64: 3529 case elfcpp::R_X86_64_32: 3530 case elfcpp::R_X86_64_32S: 3531 case elfcpp::R_X86_64_16: 3532 case elfcpp::R_X86_64_8: 3533 case elfcpp::R_X86_64_GOT64: 3534 case elfcpp::R_X86_64_GOT32: 3535 case elfcpp::R_X86_64_GOTPCREL64: 3536 case elfcpp::R_X86_64_GOTPCREL: 3537 case elfcpp::R_X86_64_GOTPCRELX: 3538 case elfcpp::R_X86_64_REX_GOTPCRELX: 3539 case elfcpp::R_X86_64_CODE_4_GOTPCRELX: 3540 case elfcpp::R_X86_64_GOTPLT64: 3541 { 3542 return true; 3543 } 3544 case elfcpp::R_X86_64_PC32: 3545 { 3546 // This relocation may be used both for function calls and 3547 // for taking address of a function. We distinguish between 3548 // them by checking the opcodes. 3549 uint64_t sh_flags = src_obj->section_flags(src_indx); 3550 bool is_executable = (sh_flags & elfcpp::SHF_EXECINSTR) != 0; 3551 if (is_executable) 3552 { 3553 section_size_type stype; 3554 const unsigned char* view = src_obj->section_contents(src_indx, 3555 &stype, 3556 true); 3557 3558 // call 3559 if (r_offset >= 1 3560 && view[r_offset - 1] == 0xe8) 3561 return false; 3562 3563 // jmp 3564 if (r_offset >= 1 3565 && view[r_offset - 1] == 0xe9) 3566 return false; 3567 3568 // jo/jno/jb/jnb/je/jne/jna/ja/js/jns/jp/jnp/jl/jge/jle/jg 3569 if (r_offset >= 2 3570 && view[r_offset - 2] == 0x0f 3571 && view[r_offset - 1] >= 0x80 3572 && view[r_offset - 1] <= 0x8f) 3573 return false; 3574 } 3575 3576 // Be conservative and treat all others as function pointers. 3577 return true; 3578 } 3579 } 3580 return false; 3581 } 3582 3583 // For safe ICF, scan a relocation for a local symbol to check if it 3584 // corresponds to a function pointer being taken. In that case mark 3585 // the function whose pointer was taken as not foldable. 3586 3587 template<int size> 3588 inline bool 3589 Target_x86_64<size>::Scan::local_reloc_may_be_function_pointer( 3590 Symbol_table* , 3591 Layout* , 3592 Target_x86_64<size>* , 3593 Sized_relobj_file<size, false>* src_obj, 3594 unsigned int src_indx, 3595 Output_section* , 3596 const elfcpp::Rela<size, false>& reloc, 3597 unsigned int r_type, 3598 const elfcpp::Sym<size, false>&) 3599 { 3600 return possible_function_pointer_reloc(src_obj, src_indx, 3601 reloc.get_r_offset(), r_type); 3602 } 3603 3604 // For safe ICF, scan a relocation for a global symbol to check if it 3605 // corresponds to a function pointer being taken. In that case mark 3606 // the function whose pointer was taken as not foldable. 3607 3608 template<int size> 3609 inline bool 3610 Target_x86_64<size>::Scan::global_reloc_may_be_function_pointer( 3611 Symbol_table*, 3612 Layout* , 3613 Target_x86_64<size>* , 3614 Sized_relobj_file<size, false>* src_obj, 3615 unsigned int src_indx, 3616 Output_section* , 3617 const elfcpp::Rela<size, false>& reloc, 3618 unsigned int r_type, 3619 Symbol*) 3620 { 3621 return possible_function_pointer_reloc(src_obj, src_indx, 3622 reloc.get_r_offset(), r_type); 3623 } 3624 3625 // Scan a relocation for a global symbol. 3626 3627 template<int size> 3628 inline void 3629 Target_x86_64<size>::Scan::global(Symbol_table* symtab, 3630 Layout* layout, 3631 Target_x86_64<size>* target, 3632 Sized_relobj_file<size, false>* object, 3633 unsigned int data_shndx, 3634 Output_section* output_section, 3635 const elfcpp::Rela<size, false>& reloc, 3636 unsigned int r_type, 3637 Symbol* gsym) 3638 { 3639 // A STT_GNU_IFUNC symbol may require a PLT entry. 3640 if (gsym->type() == elfcpp::STT_GNU_IFUNC 3641 && this->reloc_needs_plt_for_ifunc(object, r_type)) 3642 target->make_plt_entry(symtab, layout, gsym); 3643 3644 const unsigned char *reloc_view = NULL; 3645 3646 switch (r_type) 3647 { 3648 case elfcpp::R_X86_64_NONE: 3649 case elfcpp::R_X86_64_GNU_VTINHERIT: 3650 case elfcpp::R_X86_64_GNU_VTENTRY: 3651 break; 3652 3653 case elfcpp::R_X86_64_64: 3654 case elfcpp::R_X86_64_32: 3655 case elfcpp::R_X86_64_32S: 3656 case elfcpp::R_X86_64_16: 3657 case elfcpp::R_X86_64_8: 3658 { 3659 // Make a PLT entry if necessary. 3660 if (gsym->needs_plt_entry()) 3661 { 3662 target->make_plt_entry(symtab, layout, gsym); 3663 // Since this is not a PC-relative relocation, we may be 3664 // taking the address of a function. In that case we need to 3665 // set the entry in the dynamic symbol table to the address of 3666 // the PLT entry. 3667 if (gsym->is_from_dynobj() && !parameters->options().shared()) 3668 gsym->set_needs_dynsym_value(); 3669 } 3670 // Make a dynamic relocation if necessary. 3671 if (gsym->needs_dynamic_reloc(Scan::get_reference_flags(r_type))) 3672 { 3673 if (!parameters->options().output_is_position_independent() 3674 && gsym->may_need_copy_reloc()) 3675 { 3676 target->copy_reloc(symtab, layout, object, 3677 data_shndx, output_section, gsym, reloc); 3678 } 3679 else if (((size == 64 && r_type == elfcpp::R_X86_64_64) 3680 || (size == 32 && r_type == elfcpp::R_X86_64_32)) 3681 && gsym->type() == elfcpp::STT_GNU_IFUNC 3682 && gsym->can_use_relative_reloc(false) 3683 && !gsym->is_from_dynobj() 3684 && !gsym->is_undefined() 3685 && !gsym->is_preemptible()) 3686 { 3687 // Use an IRELATIVE reloc for a locally defined 3688 // STT_GNU_IFUNC symbol. This makes a function 3689 // address in a PIE executable match the address in a 3690 // shared library that it links against. 3691 Reloc_section* rela_dyn = 3692 target->rela_irelative_section(layout); 3693 unsigned int r_type = elfcpp::R_X86_64_IRELATIVE; 3694 rela_dyn->add_symbolless_global_addend(gsym, r_type, 3695 output_section, object, 3696 data_shndx, 3697 reloc.get_r_offset(), 3698 reloc.get_r_addend()); 3699 } 3700 else if (((size == 64 && r_type == elfcpp::R_X86_64_64) 3701 || (size == 32 && r_type == elfcpp::R_X86_64_32)) 3702 && gsym->can_use_relative_reloc(false)) 3703 { 3704 Reloc_section* rela_dyn = target->rela_dyn_section(layout); 3705 rela_dyn->add_global_relative(gsym, elfcpp::R_X86_64_RELATIVE, 3706 output_section, object, 3707 data_shndx, 3708 reloc.get_r_offset(), 3709 reloc.get_r_addend(), false); 3710 } 3711 else 3712 { 3713 this->check_non_pic(object, r_type, gsym); 3714 Reloc_section* rela_dyn = target->rela_dyn_section(layout); 3715 rela_dyn->add_global(gsym, r_type, output_section, object, 3716 data_shndx, reloc.get_r_offset(), 3717 reloc.get_r_addend()); 3718 } 3719 } 3720 } 3721 break; 3722 3723 case elfcpp::R_X86_64_PC64: 3724 case elfcpp::R_X86_64_PC32: 3725 case elfcpp::R_X86_64_PC16: 3726 case elfcpp::R_X86_64_PC8: 3727 { 3728 // Make a PLT entry if necessary. 3729 if (gsym->needs_plt_entry()) 3730 target->make_plt_entry(symtab, layout, gsym); 3731 // Make a dynamic relocation if necessary. 3732 if (gsym->needs_dynamic_reloc(Scan::get_reference_flags(r_type))) 3733 { 3734 if (parameters->options().output_is_executable() 3735 && gsym->may_need_copy_reloc()) 3736 { 3737 target->copy_reloc(symtab, layout, object, 3738 data_shndx, output_section, gsym, reloc); 3739 } 3740 else 3741 { 3742 this->check_non_pic(object, r_type, gsym); 3743 Reloc_section* rela_dyn = target->rela_dyn_section(layout); 3744 rela_dyn->add_global(gsym, r_type, output_section, object, 3745 data_shndx, reloc.get_r_offset(), 3746 reloc.get_r_addend()); 3747 } 3748 } 3749 } 3750 break; 3751 3752 case elfcpp::R_X86_64_GOT64: 3753 case elfcpp::R_X86_64_GOT32: 3754 case elfcpp::R_X86_64_GOTPCREL64: 3755 case elfcpp::R_X86_64_GOTPCREL: 3756 case elfcpp::R_X86_64_GOTPCRELX: 3757 case elfcpp::R_X86_64_REX_GOTPCRELX: 3758 case elfcpp::R_X86_64_CODE_4_GOTPCRELX: 3759 case elfcpp::R_X86_64_GOTPLT64: 3760 { 3761 // The symbol requires a GOT entry. 3762 Output_data_got<64, false>* got = target->got_section(symtab, layout); 3763 3764 // If we convert this from 3765 // mov foo@GOTPCREL(%rip), %reg 3766 // to lea foo(%rip), %reg. 3767 // OR 3768 // if we convert 3769 // (callq|jmpq) *foo@GOTPCRELX(%rip) to 3770 // (callq|jmpq) foo 3771 // in Relocate::relocate, then there is nothing to do here. 3772 // We cannot make these optimizations in incremental linking mode, 3773 // because we look at the opcode to decide whether or not to make 3774 // change, and during an incremental update, the change may have 3775 // already been applied. 3776 3777 Lazy_view<size> view(object, data_shndx); 3778 size_t r_offset = reloc.get_r_offset(); 3779 if (!parameters->incremental() 3780 && reloc.get_r_addend() == -4 3781 && ((r_type != elfcpp::R_X86_64_CODE_4_GOTPCRELX 3782 && r_offset >= 2) 3783 || (r_type == elfcpp::R_X86_64_CODE_4_GOTPCRELX 3784 && r_offset >= 4 3785 && view[r_offset - 4] == 0xd5)) 3786 && Target_x86_64<size>::can_convert_mov_to_lea(gsym, r_type, 3787 r_offset, &view)) 3788 break; 3789 3790 if (!parameters->incremental() 3791 && r_offset >= 2 3792 && Target_x86_64<size>::can_convert_callq_to_direct(gsym, r_type, 3793 r_offset, 3794 &view)) 3795 break; 3796 3797 if (gsym->final_value_is_known()) 3798 { 3799 // For a STT_GNU_IFUNC symbol we want the PLT address. 3800 if (gsym->type() == elfcpp::STT_GNU_IFUNC) 3801 got->add_global_plt(gsym, GOT_TYPE_STANDARD); 3802 else 3803 got->add_global(gsym, GOT_TYPE_STANDARD); 3804 } 3805 else 3806 { 3807 // If this symbol is not fully resolved, we need to add a 3808 // dynamic relocation for it. 3809 Reloc_section* rela_dyn = target->rela_dyn_section(layout); 3810 3811 // Use a GLOB_DAT rather than a RELATIVE reloc if: 3812 // 3813 // 1) The symbol may be defined in some other module. 3814 // 3815 // 2) We are building a shared library and this is a 3816 // protected symbol; using GLOB_DAT means that the dynamic 3817 // linker can use the address of the PLT in the main 3818 // executable when appropriate so that function address 3819 // comparisons work. 3820 // 3821 // 3) This is a STT_GNU_IFUNC symbol in position dependent 3822 // code, again so that function address comparisons work. 3823 if (gsym->is_from_dynobj() 3824 || gsym->is_undefined() 3825 || gsym->is_preemptible() 3826 || (gsym->visibility() == elfcpp::STV_PROTECTED 3827 && parameters->options().shared()) 3828 || (gsym->type() == elfcpp::STT_GNU_IFUNC 3829 && parameters->options().output_is_position_independent())) 3830 got->add_global_with_rel(gsym, GOT_TYPE_STANDARD, rela_dyn, 3831 elfcpp::R_X86_64_GLOB_DAT); 3832 else 3833 { 3834 // For a STT_GNU_IFUNC symbol we want to write the PLT 3835 // offset into the GOT, so that function pointer 3836 // comparisons work correctly. 3837 bool is_new; 3838 if (gsym->type() != elfcpp::STT_GNU_IFUNC) 3839 is_new = got->add_global(gsym, GOT_TYPE_STANDARD); 3840 else 3841 { 3842 is_new = got->add_global_plt(gsym, GOT_TYPE_STANDARD); 3843 // Tell the dynamic linker to use the PLT address 3844 // when resolving relocations. 3845 if (gsym->is_from_dynobj() 3846 && !parameters->options().shared()) 3847 gsym->set_needs_dynsym_value(); 3848 } 3849 if (is_new) 3850 { 3851 unsigned int got_off = gsym->got_offset(GOT_TYPE_STANDARD); 3852 rela_dyn->add_global_relative(gsym, 3853 elfcpp::R_X86_64_RELATIVE, 3854 got, got_off, 0, false); 3855 } 3856 } 3857 } 3858 } 3859 break; 3860 3861 case elfcpp::R_X86_64_PLT32: 3862 // If the symbol is fully resolved, this is just a PC32 reloc. 3863 // Otherwise we need a PLT entry. 3864 if (gsym->final_value_is_known()) 3865 break; 3866 // If building a shared library, we can also skip the PLT entry 3867 // if the symbol is defined in the output file and is protected 3868 // or hidden. 3869 if (gsym->is_defined() 3870 && !gsym->is_from_dynobj() 3871 && !gsym->is_preemptible()) 3872 break; 3873 target->make_plt_entry(symtab, layout, gsym); 3874 break; 3875 3876 case elfcpp::R_X86_64_GOTPC32: 3877 case elfcpp::R_X86_64_GOTOFF64: 3878 case elfcpp::R_X86_64_GOTPC64: 3879 case elfcpp::R_X86_64_PLTOFF64: 3880 // We need a GOT section. 3881 target->got_section(symtab, layout); 3882 // For PLTOFF64, we also need a PLT entry (but only if the 3883 // symbol is not fully resolved). 3884 if (r_type == elfcpp::R_X86_64_PLTOFF64 3885 && !gsym->final_value_is_known()) 3886 target->make_plt_entry(symtab, layout, gsym); 3887 break; 3888 3889 case elfcpp::R_X86_64_COPY: 3890 case elfcpp::R_X86_64_GLOB_DAT: 3891 case elfcpp::R_X86_64_JUMP_SLOT: 3892 case elfcpp::R_X86_64_RELATIVE: 3893 case elfcpp::R_X86_64_IRELATIVE: 3894 // These are outstanding tls relocs, which are unexpected when linking 3895 case elfcpp::R_X86_64_TPOFF64: 3896 case elfcpp::R_X86_64_DTPMOD64: 3897 case elfcpp::R_X86_64_TLSDESC: 3898 gold_error(_("%s: unexpected reloc %u in object file"), 3899 object->name().c_str(), r_type); 3900 break; 3901 3902 // These are initial tls relocs, which are expected for global() 3903 case elfcpp::R_X86_64_CODE_4_GOTPC32_TLSDESC: 3904 case elfcpp::R_X86_64_CODE_4_GOTTPOFF: 3905 { 3906 section_size_type stype; 3907 reloc_view = object->section_contents(data_shndx, &stype, true); 3908 } 3909 // Fall through. 3910 case elfcpp::R_X86_64_TLSGD: // Global-dynamic 3911 case elfcpp::R_X86_64_GOTPC32_TLSDESC: // Global-dynamic (from ~oliva url) 3912 case elfcpp::R_X86_64_TLSDESC_CALL: 3913 case elfcpp::R_X86_64_TLSLD: // Local-dynamic 3914 case elfcpp::R_X86_64_DTPOFF32: 3915 case elfcpp::R_X86_64_DTPOFF64: 3916 case elfcpp::R_X86_64_GOTTPOFF: // Initial-exec 3917 case elfcpp::R_X86_64_TPOFF32: // Local-exec 3918 { 3919 // For the Initial-Exec model, we can treat undef symbols as final 3920 // when building an executable. 3921 const bool is_final = (gsym->final_value_is_known() || 3922 ((r_type == elfcpp::R_X86_64_GOTTPOFF || 3923 r_type == elfcpp::R_X86_64_CODE_4_GOTTPOFF) && 3924 gsym->is_undefined() && 3925 parameters->options().output_is_executable())); 3926 size_t r_offset = reloc.get_r_offset(); 3927 const tls::Tls_optimization optimized_type 3928 = Target_x86_64<size>::optimize_tls_reloc(is_final, r_type, 3929 r_offset, 3930 reloc_view + r_offset); 3931 switch (r_type) 3932 { 3933 case elfcpp::R_X86_64_TLSGD: // General-dynamic 3934 if (optimized_type == tls::TLSOPT_NONE) 3935 { 3936 // Create a pair of GOT entries for the module index and 3937 // dtv-relative offset. 3938 Output_data_got<64, false>* got 3939 = target->got_section(symtab, layout); 3940 got->add_global_pair_with_rel(gsym, GOT_TYPE_TLS_PAIR, 3941 target->rela_dyn_section(layout), 3942 elfcpp::R_X86_64_DTPMOD64, 3943 elfcpp::R_X86_64_DTPOFF64); 3944 } 3945 else if (optimized_type == tls::TLSOPT_TO_IE) 3946 { 3947 // Create a GOT entry for the tp-relative offset. 3948 Output_data_got<64, false>* got 3949 = target->got_section(symtab, layout); 3950 got->add_global_with_rel(gsym, GOT_TYPE_TLS_OFFSET, 3951 target->rela_dyn_section(layout), 3952 elfcpp::R_X86_64_TPOFF64); 3953 } 3954 else if (optimized_type != tls::TLSOPT_TO_LE) 3955 unsupported_reloc_global(object, r_type, gsym); 3956 break; 3957 3958 case elfcpp::R_X86_64_GOTPC32_TLSDESC: 3959 case elfcpp::R_X86_64_CODE_4_GOTPC32_TLSDESC: 3960 target->define_tls_base_symbol(symtab, layout); 3961 if (optimized_type == tls::TLSOPT_NONE) 3962 { 3963 // Create reserved PLT and GOT entries for the resolver. 3964 target->reserve_tlsdesc_entries(symtab, layout); 3965 3966 // Create a double GOT entry with an R_X86_64_TLSDESC 3967 // reloc. The R_X86_64_TLSDESC reloc is resolved 3968 // lazily, so the GOT entry needs to be in an area in 3969 // .got.plt, not .got. Call got_section to make sure 3970 // the section has been created. 3971 target->got_section(symtab, layout); 3972 Output_data_got<64, false>* got = target->got_tlsdesc_section(); 3973 Reloc_section* rt = target->rela_tlsdesc_section(layout); 3974 got->add_global_pair_with_rel(gsym, GOT_TYPE_TLS_DESC, rt, 3975 elfcpp::R_X86_64_TLSDESC, 0); 3976 } 3977 else if (optimized_type == tls::TLSOPT_TO_IE) 3978 { 3979 // Create a GOT entry for the tp-relative offset. 3980 Output_data_got<64, false>* got 3981 = target->got_section(symtab, layout); 3982 got->add_global_with_rel(gsym, GOT_TYPE_TLS_OFFSET, 3983 target->rela_dyn_section(layout), 3984 elfcpp::R_X86_64_TPOFF64); 3985 } 3986 else if (optimized_type != tls::TLSOPT_TO_LE) 3987 unsupported_reloc_global(object, r_type, gsym); 3988 break; 3989 3990 case elfcpp::R_X86_64_TLSDESC_CALL: 3991 break; 3992 3993 case elfcpp::R_X86_64_TLSLD: // Local-dynamic 3994 if (optimized_type == tls::TLSOPT_NONE) 3995 { 3996 // Create a GOT entry for the module index. 3997 target->got_mod_index_entry(symtab, layout, object); 3998 } 3999 else if (optimized_type != tls::TLSOPT_TO_LE) 4000 unsupported_reloc_global(object, r_type, gsym); 4001 break; 4002 4003 case elfcpp::R_X86_64_DTPOFF32: 4004 case elfcpp::R_X86_64_DTPOFF64: 4005 break; 4006 4007 case elfcpp::R_X86_64_GOTTPOFF: // Initial-exec 4008 case elfcpp::R_X86_64_CODE_4_GOTTPOFF: 4009 layout->set_has_static_tls(); 4010 if (optimized_type == tls::TLSOPT_NONE) 4011 { 4012 // Create a GOT entry for the tp-relative offset. 4013 Output_data_got<64, false>* got 4014 = target->got_section(symtab, layout); 4015 got->add_global_with_rel(gsym, GOT_TYPE_TLS_OFFSET, 4016 target->rela_dyn_section(layout), 4017 elfcpp::R_X86_64_TPOFF64); 4018 } 4019 else if (optimized_type != tls::TLSOPT_TO_LE) 4020 unsupported_reloc_global(object, r_type, gsym); 4021 break; 4022 4023 case elfcpp::R_X86_64_TPOFF32: // Local-exec 4024 layout->set_has_static_tls(); 4025 if (parameters->options().shared()) 4026 unsupported_reloc_global(object, r_type, gsym); 4027 break; 4028 4029 default: 4030 gold_unreachable(); 4031 } 4032 } 4033 break; 4034 4035 case elfcpp::R_X86_64_SIZE32: 4036 case elfcpp::R_X86_64_SIZE64: 4037 default: 4038 gold_error(_("%s: unsupported reloc %u against global symbol %s"), 4039 object->name().c_str(), r_type, 4040 gsym->demangled_name().c_str()); 4041 break; 4042 } 4043 } 4044 4045 template<int size> 4046 void 4047 Target_x86_64<size>::gc_process_relocs(Symbol_table* symtab, 4048 Layout* layout, 4049 Sized_relobj_file<size, false>* object, 4050 unsigned int data_shndx, 4051 unsigned int sh_type, 4052 const unsigned char* prelocs, 4053 size_t reloc_count, 4054 Output_section* output_section, 4055 bool needs_special_offset_handling, 4056 size_t local_symbol_count, 4057 const unsigned char* plocal_symbols) 4058 { 4059 typedef gold::Default_classify_reloc<elfcpp::SHT_RELA, size, false> 4060 Classify_reloc; 4061 4062 if (sh_type == elfcpp::SHT_REL) 4063 { 4064 return; 4065 } 4066 4067 gold::gc_process_relocs<size, false, Target_x86_64<size>, Scan, 4068 Classify_reloc>( 4069 symtab, 4070 layout, 4071 this, 4072 object, 4073 data_shndx, 4074 prelocs, 4075 reloc_count, 4076 output_section, 4077 needs_special_offset_handling, 4078 local_symbol_count, 4079 plocal_symbols); 4080 4081 } 4082 // Scan relocations for a section. 4083 4084 template<int size> 4085 void 4086 Target_x86_64<size>::scan_relocs(Symbol_table* symtab, 4087 Layout* layout, 4088 Sized_relobj_file<size, false>* object, 4089 unsigned int data_shndx, 4090 unsigned int sh_type, 4091 const unsigned char* prelocs, 4092 size_t reloc_count, 4093 Output_section* output_section, 4094 bool needs_special_offset_handling, 4095 size_t local_symbol_count, 4096 const unsigned char* plocal_symbols) 4097 { 4098 typedef gold::Default_classify_reloc<elfcpp::SHT_RELA, size, false> 4099 Classify_reloc; 4100 4101 if (sh_type == elfcpp::SHT_REL) 4102 { 4103 gold_error(_("%s: unsupported REL reloc section"), 4104 object->name().c_str()); 4105 return; 4106 } 4107 4108 gold::scan_relocs<size, false, Target_x86_64<size>, Scan, Classify_reloc>( 4109 symtab, 4110 layout, 4111 this, 4112 object, 4113 data_shndx, 4114 prelocs, 4115 reloc_count, 4116 output_section, 4117 needs_special_offset_handling, 4118 local_symbol_count, 4119 plocal_symbols); 4120 } 4121 4122 // Finalize the sections. 4123 4124 template<int size> 4125 void 4126 Target_x86_64<size>::do_finalize_sections( 4127 Layout* layout, 4128 const Input_objects*, 4129 Symbol_table* symtab) 4130 { 4131 const Reloc_section* rel_plt = (this->plt_ == NULL 4132 ? NULL 4133 : this->plt_->rela_plt()); 4134 layout->add_target_dynamic_tags(false, this->got_plt_, rel_plt, 4135 this->rela_dyn_, true, false, false); 4136 4137 // Fill in some more dynamic tags. 4138 Output_data_dynamic* const odyn = layout->dynamic_data(); 4139 if (odyn != NULL) 4140 { 4141 if (this->plt_ != NULL 4142 && this->plt_->output_section() != NULL 4143 && this->plt_->has_tlsdesc_entry()) 4144 { 4145 unsigned int plt_offset = this->plt_->get_tlsdesc_plt_offset(); 4146 unsigned int got_offset = this->plt_->get_tlsdesc_got_offset(); 4147 this->got_->finalize_data_size(); 4148 odyn->add_section_plus_offset(elfcpp::DT_TLSDESC_PLT, 4149 this->plt_, plt_offset); 4150 odyn->add_section_plus_offset(elfcpp::DT_TLSDESC_GOT, 4151 this->got_, got_offset); 4152 } 4153 } 4154 4155 // Emit any relocs we saved in an attempt to avoid generating COPY 4156 // relocs. 4157 if (this->copy_relocs_.any_saved_relocs()) 4158 this->copy_relocs_.emit(this->rela_dyn_section(layout)); 4159 4160 // Set the size of the _GLOBAL_OFFSET_TABLE_ symbol to the size of 4161 // the .got.plt section. 4162 Symbol* sym = this->global_offset_table_; 4163 if (sym != NULL) 4164 { 4165 uint64_t data_size = this->got_plt_->current_data_size(); 4166 symtab->get_sized_symbol<size>(sym)->set_symsize(data_size); 4167 } 4168 4169 if (parameters->doing_static_link() 4170 && (this->plt_ == NULL || !this->plt_->has_irelative_section())) 4171 { 4172 // If linking statically, make sure that the __rela_iplt symbols 4173 // were defined if necessary, even if we didn't create a PLT. 4174 static const Define_symbol_in_segment syms[] = 4175 { 4176 { 4177 "__rela_iplt_start", // name 4178 elfcpp::PT_LOAD, // segment_type 4179 elfcpp::PF_W, // segment_flags_set 4180 elfcpp::PF(0), // segment_flags_clear 4181 0, // value 4182 0, // size 4183 elfcpp::STT_NOTYPE, // type 4184 elfcpp::STB_GLOBAL, // binding 4185 elfcpp::STV_HIDDEN, // visibility 4186 0, // nonvis 4187 Symbol::SEGMENT_START, // offset_from_base 4188 true // only_if_ref 4189 }, 4190 { 4191 "__rela_iplt_end", // name 4192 elfcpp::PT_LOAD, // segment_type 4193 elfcpp::PF_W, // segment_flags_set 4194 elfcpp::PF(0), // segment_flags_clear 4195 0, // value 4196 0, // size 4197 elfcpp::STT_NOTYPE, // type 4198 elfcpp::STB_GLOBAL, // binding 4199 elfcpp::STV_HIDDEN, // visibility 4200 0, // nonvis 4201 Symbol::SEGMENT_START, // offset_from_base 4202 true // only_if_ref 4203 } 4204 }; 4205 4206 symtab->define_symbols(layout, 2, syms, 4207 layout->script_options()->saw_sections_clause()); 4208 } 4209 } 4210 4211 // For x32, we need to handle PC-relative relocations using full 64-bit 4212 // arithmetic, so that we can detect relocation overflows properly. 4213 // This class overrides the pcrela32_check methods from the defaults in 4214 // Relocate_functions in reloc.h. 4215 4216 template<int size> 4217 class X86_64_relocate_functions : public Relocate_functions<size, false> 4218 { 4219 public: 4220 typedef Relocate_functions<size, false> Base; 4221 4222 // Do a simple PC relative relocation with the addend in the 4223 // relocation. 4224 static inline typename Base::Reloc_status 4225 pcrela32_check(unsigned char* view, 4226 typename elfcpp::Elf_types<64>::Elf_Addr value, 4227 typename elfcpp::Elf_types<64>::Elf_Swxword addend, 4228 typename elfcpp::Elf_types<64>::Elf_Addr address) 4229 { 4230 typedef typename elfcpp::Swap<32, false>::Valtype Valtype; 4231 Valtype* wv = reinterpret_cast<Valtype*>(view); 4232 value = value + addend - address; 4233 elfcpp::Swap<32, false>::writeval(wv, value); 4234 return (Bits<32>::has_overflow(value) 4235 ? Base::RELOC_OVERFLOW : Base::RELOC_OK); 4236 } 4237 4238 // Do a simple PC relative relocation with a Symbol_value with the 4239 // addend in the relocation. 4240 static inline typename Base::Reloc_status 4241 pcrela32_check(unsigned char* view, 4242 const Sized_relobj_file<size, false>* object, 4243 const Symbol_value<size>* psymval, 4244 typename elfcpp::Elf_types<64>::Elf_Swxword addend, 4245 typename elfcpp::Elf_types<64>::Elf_Addr address) 4246 { 4247 typedef typename elfcpp::Swap<32, false>::Valtype Valtype; 4248 Valtype* wv = reinterpret_cast<Valtype*>(view); 4249 typename elfcpp::Elf_types<64>::Elf_Addr value; 4250 if (addend >= 0) 4251 value = psymval->value(object, addend); 4252 else 4253 { 4254 // For negative addends, get the symbol value without 4255 // the addend, then add the addend using 64-bit arithmetic. 4256 value = psymval->value(object, 0); 4257 value += addend; 4258 } 4259 value -= address; 4260 elfcpp::Swap<32, false>::writeval(wv, value); 4261 return (Bits<32>::has_overflow(value) 4262 ? Base::RELOC_OVERFLOW : Base::RELOC_OK); 4263 } 4264 }; 4265 4266 // Perform a relocation. 4267 4268 template<int size> 4269 inline bool 4270 Target_x86_64<size>::Relocate::relocate( 4271 const Relocate_info<size, false>* relinfo, 4272 unsigned int, 4273 Target_x86_64<size>* target, 4274 Output_section*, 4275 size_t relnum, 4276 const unsigned char* preloc, 4277 const Sized_symbol<size>* gsym, 4278 const Symbol_value<size>* psymval, 4279 unsigned char* view, 4280 typename elfcpp::Elf_types<size>::Elf_Addr address, 4281 section_size_type view_size) 4282 { 4283 typedef X86_64_relocate_functions<size> Reloc_funcs; 4284 const elfcpp::Rela<size, false> rela(preloc); 4285 unsigned int r_type = elfcpp::elf_r_type<size>(rela.get_r_info()); 4286 4287 if (this->skip_call_tls_get_addr_) 4288 { 4289 if ((r_type != elfcpp::R_X86_64_PLT32 4290 && r_type != elfcpp::R_X86_64_GOTPCREL 4291 && r_type != elfcpp::R_X86_64_GOTPCRELX 4292 && r_type != elfcpp::R_X86_64_PC32) 4293 || gsym == NULL 4294 || strcmp(gsym->name(), "__tls_get_addr") != 0) 4295 { 4296 gold_error_at_location(relinfo, relnum, rela.get_r_offset(), 4297 _("missing expected TLS relocation")); 4298 this->skip_call_tls_get_addr_ = false; 4299 } 4300 else 4301 { 4302 this->skip_call_tls_get_addr_ = false; 4303 return false; 4304 } 4305 } 4306 4307 if (view == NULL) 4308 return true; 4309 4310 const Sized_relobj_file<size, false>* object = relinfo->object; 4311 4312 // Pick the value to use for symbols defined in the PLT. 4313 Symbol_value<size> symval; 4314 if (gsym != NULL 4315 && gsym->use_plt_offset(Scan::get_reference_flags(r_type))) 4316 { 4317 symval.set_output_value(target->plt_address_for_global(gsym)); 4318 psymval = &symval; 4319 } 4320 else if (gsym == NULL && psymval->is_ifunc_symbol()) 4321 { 4322 unsigned int r_sym = elfcpp::elf_r_sym<size>(rela.get_r_info()); 4323 if (object->local_has_plt_offset(r_sym)) 4324 { 4325 symval.set_output_value(target->plt_address_for_local(object, r_sym)); 4326 psymval = &symval; 4327 } 4328 } 4329 4330 const elfcpp::Elf_Xword addend = rela.get_r_addend(); 4331 4332 // Get the GOT offset if needed. 4333 // The GOT pointer points to the end of the GOT section. 4334 // We need to subtract the size of the GOT section to get 4335 // the actual offset to use in the relocation. 4336 bool have_got_offset = false; 4337 // Since the actual offset is always negative, we use signed int to 4338 // support 64-bit GOT relocations. 4339 int got_offset = 0; 4340 switch (r_type) 4341 { 4342 case elfcpp::R_X86_64_GOT32: 4343 case elfcpp::R_X86_64_GOT64: 4344 case elfcpp::R_X86_64_GOTPLT64: 4345 case elfcpp::R_X86_64_GOTPCREL64: 4346 if (gsym != NULL) 4347 { 4348 gold_assert(gsym->has_got_offset(GOT_TYPE_STANDARD)); 4349 got_offset = gsym->got_offset(GOT_TYPE_STANDARD) - target->got_size(); 4350 } 4351 else 4352 { 4353 unsigned int r_sym = elfcpp::elf_r_sym<size>(rela.get_r_info()); 4354 gold_assert(object->local_has_got_offset(r_sym, GOT_TYPE_STANDARD)); 4355 got_offset = (object->local_got_offset(r_sym, GOT_TYPE_STANDARD) 4356 - target->got_size()); 4357 } 4358 have_got_offset = true; 4359 break; 4360 4361 default: 4362 break; 4363 } 4364 4365 typename Reloc_funcs::Reloc_status rstatus = Reloc_funcs::RELOC_OK; 4366 4367 switch (r_type) 4368 { 4369 case elfcpp::R_X86_64_NONE: 4370 case elfcpp::R_X86_64_GNU_VTINHERIT: 4371 case elfcpp::R_X86_64_GNU_VTENTRY: 4372 break; 4373 4374 case elfcpp::R_X86_64_64: 4375 Reloc_funcs::rela64(view, object, psymval, addend); 4376 break; 4377 4378 case elfcpp::R_X86_64_PC64: 4379 Reloc_funcs::pcrela64(view, object, psymval, addend, 4380 address); 4381 break; 4382 4383 case elfcpp::R_X86_64_32: 4384 rstatus = Reloc_funcs::rela32_check(view, object, psymval, addend, 4385 Reloc_funcs::CHECK_UNSIGNED); 4386 break; 4387 4388 case elfcpp::R_X86_64_32S: 4389 rstatus = Reloc_funcs::rela32_check(view, object, psymval, addend, 4390 Reloc_funcs::CHECK_SIGNED); 4391 break; 4392 4393 case elfcpp::R_X86_64_PC32: 4394 rstatus = Reloc_funcs::pcrela32_check(view, object, psymval, addend, 4395 address); 4396 break; 4397 4398 case elfcpp::R_X86_64_16: 4399 Reloc_funcs::rela16(view, object, psymval, addend); 4400 break; 4401 4402 case elfcpp::R_X86_64_PC16: 4403 Reloc_funcs::pcrela16(view, object, psymval, addend, address); 4404 break; 4405 4406 case elfcpp::R_X86_64_8: 4407 Reloc_funcs::rela8(view, object, psymval, addend); 4408 break; 4409 4410 case elfcpp::R_X86_64_PC8: 4411 Reloc_funcs::pcrela8(view, object, psymval, addend, address); 4412 break; 4413 4414 case elfcpp::R_X86_64_PLT32: 4415 gold_assert(gsym == NULL 4416 || gsym->has_plt_offset() 4417 || gsym->final_value_is_known() 4418 || (gsym->is_defined() 4419 && !gsym->is_from_dynobj() 4420 && !gsym->is_preemptible())); 4421 // Note: while this code looks the same as for R_X86_64_PC32, it 4422 // behaves differently because psymval was set to point to 4423 // the PLT entry, rather than the symbol, in Scan::global(). 4424 rstatus = Reloc_funcs::pcrela32_check(view, object, psymval, addend, 4425 address); 4426 break; 4427 4428 case elfcpp::R_X86_64_PLTOFF64: 4429 { 4430 gold_assert(gsym); 4431 gold_assert(gsym->has_plt_offset() 4432 || gsym->final_value_is_known()); 4433 typename elfcpp::Elf_types<size>::Elf_Addr got_address; 4434 // This is the address of GLOBAL_OFFSET_TABLE. 4435 got_address = target->got_plt_section()->address(); 4436 Reloc_funcs::rela64(view, object, psymval, addend - got_address); 4437 } 4438 break; 4439 4440 case elfcpp::R_X86_64_GOT32: 4441 gold_assert(have_got_offset); 4442 Reloc_funcs::rela32(view, got_offset, addend); 4443 break; 4444 4445 case elfcpp::R_X86_64_GOTPC32: 4446 { 4447 gold_assert(gsym); 4448 typename elfcpp::Elf_types<size>::Elf_Addr value; 4449 value = target->got_plt_section()->address(); 4450 Reloc_funcs::pcrela32_check(view, value, addend, address); 4451 } 4452 break; 4453 4454 case elfcpp::R_X86_64_GOT64: 4455 case elfcpp::R_X86_64_GOTPLT64: 4456 // R_X86_64_GOTPLT64 is obsolete and treated the same as 4457 // GOT64. 4458 gold_assert(have_got_offset); 4459 Reloc_funcs::rela64(view, got_offset, addend); 4460 break; 4461 4462 case elfcpp::R_X86_64_GOTPC64: 4463 { 4464 gold_assert(gsym); 4465 typename elfcpp::Elf_types<size>::Elf_Addr value; 4466 value = target->got_plt_section()->address(); 4467 Reloc_funcs::pcrela64(view, value, addend, address); 4468 } 4469 break; 4470 4471 case elfcpp::R_X86_64_GOTOFF64: 4472 { 4473 typename elfcpp::Elf_types<size>::Elf_Addr reladdr; 4474 reladdr = target->got_plt_section()->address(); 4475 Reloc_funcs::pcrela64(view, object, psymval, addend, reladdr); 4476 } 4477 break; 4478 4479 case elfcpp::R_X86_64_GOTPCREL: 4480 case elfcpp::R_X86_64_GOTPCRELX: 4481 case elfcpp::R_X86_64_REX_GOTPCRELX: 4482 case elfcpp::R_X86_64_CODE_4_GOTPCRELX: 4483 { 4484 bool converted_p = false; 4485 4486 if (rela.get_r_addend() == -4) 4487 { 4488 // Convert 4489 // mov foo@GOTPCREL(%rip), %reg 4490 // to lea foo(%rip), %reg. 4491 // if possible. 4492 if (!parameters->incremental() 4493 && ((gsym == NULL 4494 && rela.get_r_offset() >= 2 4495 && view[-2] == 0x8b 4496 && !psymval->is_ifunc_symbol()) 4497 || (gsym != NULL 4498 && rela.get_r_offset() >= 2 4499 && Target_x86_64<size>::can_convert_mov_to_lea(gsym, 4500 r_type, 4501 0, 4502 &view)))) 4503 { 4504 view[-2] = 0x8d; 4505 Reloc_funcs::pcrela32(view, object, psymval, addend, address); 4506 converted_p = true; 4507 } 4508 // Convert 4509 // callq *foo@GOTPCRELX(%rip) to 4510 // addr32 callq foo 4511 // and jmpq *foo@GOTPCRELX(%rip) to 4512 // jmpq foo 4513 // nop 4514 else if (!parameters->incremental() 4515 && gsym != NULL 4516 && rela.get_r_offset() >= 2 4517 && Target_x86_64<size>::can_convert_callq_to_direct(gsym, 4518 r_type, 4519 0, 4520 &view)) 4521 { 4522 if (view[-1] == 0x15) 4523 { 4524 // Convert callq *foo@GOTPCRELX(%rip) to addr32 callq. 4525 // Opcode of addr32 is 0x67 and opcode of direct callq 4526 // is 0xe8. 4527 view[-2] = 0x67; 4528 view[-1] = 0xe8; 4529 // Convert GOTPCRELX to 32-bit pc relative reloc. 4530 Reloc_funcs::pcrela32(view, object, psymval, addend, 4531 address); 4532 converted_p = true; 4533 } 4534 else 4535 { 4536 // Convert jmpq *foo@GOTPCRELX(%rip) to 4537 // jmpq foo 4538 // nop 4539 // The opcode of direct jmpq is 0xe9. 4540 view[-2] = 0xe9; 4541 // The opcode of nop is 0x90. 4542 view[3] = 0x90; 4543 // Convert GOTPCRELX to 32-bit pc relative reloc. jmpq 4544 // is rip relative and since the instruction following 4545 // the jmpq is now the nop, offset the address by 1 4546 // byte. The start of the relocation also moves ahead 4547 // by 1 byte. 4548 Reloc_funcs::pcrela32(&view[-1], object, psymval, addend, 4549 address - 1); 4550 converted_p = true; 4551 } 4552 } 4553 } 4554 4555 if (!converted_p) 4556 { 4557 if (gsym != NULL) 4558 { 4559 gold_assert(gsym->has_got_offset(GOT_TYPE_STANDARD)); 4560 got_offset = (gsym->got_offset(GOT_TYPE_STANDARD) 4561 - target->got_size()); 4562 } 4563 else 4564 { 4565 unsigned int r_sym = elfcpp::elf_r_sym<size>(rela.get_r_info()); 4566 gold_assert(object->local_has_got_offset(r_sym, 4567 GOT_TYPE_STANDARD)); 4568 got_offset = (object->local_got_offset(r_sym, GOT_TYPE_STANDARD) 4569 - target->got_size()); 4570 } 4571 typename elfcpp::Elf_types<size>::Elf_Addr value; 4572 value = target->got_plt_section()->address() + got_offset; 4573 Reloc_funcs::pcrela32_check(view, value, addend, address); 4574 } 4575 } 4576 break; 4577 4578 case elfcpp::R_X86_64_GOTPCREL64: 4579 { 4580 gold_assert(have_got_offset); 4581 typename elfcpp::Elf_types<size>::Elf_Addr value; 4582 value = target->got_plt_section()->address() + got_offset; 4583 Reloc_funcs::pcrela64(view, value, addend, address); 4584 } 4585 break; 4586 4587 case elfcpp::R_X86_64_COPY: 4588 case elfcpp::R_X86_64_GLOB_DAT: 4589 case elfcpp::R_X86_64_JUMP_SLOT: 4590 case elfcpp::R_X86_64_RELATIVE: 4591 case elfcpp::R_X86_64_IRELATIVE: 4592 // These are outstanding tls relocs, which are unexpected when linking 4593 case elfcpp::R_X86_64_TPOFF64: 4594 case elfcpp::R_X86_64_DTPMOD64: 4595 case elfcpp::R_X86_64_TLSDESC: 4596 gold_error_at_location(relinfo, relnum, rela.get_r_offset(), 4597 _("unexpected reloc %u in object file"), 4598 r_type); 4599 break; 4600 4601 // These are initial tls relocs, which are expected when linking 4602 case elfcpp::R_X86_64_TLSGD: // Global-dynamic 4603 case elfcpp::R_X86_64_GOTPC32_TLSDESC: // Global-dynamic (from ~oliva url) 4604 case elfcpp::R_X86_64_CODE_4_GOTPC32_TLSDESC: 4605 case elfcpp::R_X86_64_TLSDESC_CALL: 4606 case elfcpp::R_X86_64_TLSLD: // Local-dynamic 4607 case elfcpp::R_X86_64_DTPOFF32: 4608 case elfcpp::R_X86_64_DTPOFF64: 4609 case elfcpp::R_X86_64_GOTTPOFF: // Initial-exec 4610 case elfcpp::R_X86_64_CODE_4_GOTTPOFF: 4611 case elfcpp::R_X86_64_TPOFF32: // Local-exec 4612 this->relocate_tls(relinfo, target, relnum, rela, r_type, gsym, psymval, 4613 view, address, view_size); 4614 break; 4615 4616 case elfcpp::R_X86_64_SIZE32: 4617 case elfcpp::R_X86_64_SIZE64: 4618 default: 4619 gold_error_at_location(relinfo, relnum, rela.get_r_offset(), 4620 _("unsupported reloc %u"), 4621 r_type); 4622 break; 4623 } 4624 4625 if (rstatus == Reloc_funcs::RELOC_OVERFLOW) 4626 { 4627 if (gsym == NULL) 4628 { 4629 unsigned int r_sym = elfcpp::elf_r_sym<size>(rela.get_r_info()); 4630 gold_error_at_location(relinfo, relnum, rela.get_r_offset(), 4631 _("relocation overflow: " 4632 "reference to local symbol %u in %s"), 4633 r_sym, object->name().c_str()); 4634 } 4635 else if (gsym->is_defined() && gsym->source() == Symbol::FROM_OBJECT) 4636 { 4637 gold_error_at_location(relinfo, relnum, rela.get_r_offset(), 4638 _("relocation overflow: " 4639 "reference to '%s' defined in %s"), 4640 gsym->name(), 4641 gsym->object()->name().c_str()); 4642 } 4643 else 4644 { 4645 gold_error_at_location(relinfo, relnum, rela.get_r_offset(), 4646 _("relocation overflow: reference to '%s'"), 4647 gsym->name()); 4648 } 4649 } 4650 4651 return true; 4652 } 4653 4654 // Perform a TLS relocation. 4655 4656 template<int size> 4657 inline void 4658 Target_x86_64<size>::Relocate::relocate_tls( 4659 const Relocate_info<size, false>* relinfo, 4660 Target_x86_64<size>* target, 4661 size_t relnum, 4662 const elfcpp::Rela<size, false>& rela, 4663 unsigned int r_type, 4664 const Sized_symbol<size>* gsym, 4665 const Symbol_value<size>* psymval, 4666 unsigned char* view, 4667 typename elfcpp::Elf_types<size>::Elf_Addr address, 4668 section_size_type view_size) 4669 { 4670 Output_segment* tls_segment = relinfo->layout->tls_segment(); 4671 4672 const Sized_relobj_file<size, false>* object = relinfo->object; 4673 const elfcpp::Elf_Xword addend = rela.get_r_addend(); 4674 elfcpp::Shdr<size, false> data_shdr(relinfo->data_shdr); 4675 bool is_executable = (data_shdr.get_sh_flags() & elfcpp::SHF_EXECINSTR) != 0; 4676 4677 typename elfcpp::Elf_types<size>::Elf_Addr value = psymval->value(relinfo->object, 0); 4678 4679 const bool is_final = (gsym == NULL 4680 ? !parameters->options().shared() 4681 : gsym->final_value_is_known()); 4682 size_t r_offset = rela.get_r_offset(); 4683 tls::Tls_optimization optimized_type 4684 = Target_x86_64<size>::optimize_tls_reloc(is_final, r_type, 4685 r_offset, view); 4686 switch (r_type) 4687 { 4688 case elfcpp::R_X86_64_TLSGD: // Global-dynamic 4689 if (!is_executable && optimized_type == tls::TLSOPT_TO_LE) 4690 { 4691 // If this code sequence is used in a non-executable section, 4692 // we will not optimize the R_X86_64_DTPOFF32/64 relocation, 4693 // on the assumption that it's being used by itself in a debug 4694 // section. Therefore, in the unlikely event that the code 4695 // sequence appears in a non-executable section, we simply 4696 // leave it unoptimized. 4697 optimized_type = tls::TLSOPT_NONE; 4698 } 4699 if (optimized_type == tls::TLSOPT_TO_LE) 4700 { 4701 if (tls_segment == NULL) 4702 { 4703 gold_assert(parameters->errors()->error_count() > 0 4704 || issue_undefined_symbol_error(gsym)); 4705 return; 4706 } 4707 this->tls_gd_to_le(relinfo, relnum, tls_segment, 4708 rela, r_type, value, view, 4709 view_size); 4710 break; 4711 } 4712 else 4713 { 4714 unsigned int got_type = (optimized_type == tls::TLSOPT_TO_IE 4715 ? GOT_TYPE_TLS_OFFSET 4716 : GOT_TYPE_TLS_PAIR); 4717 unsigned int got_offset; 4718 if (gsym != NULL) 4719 { 4720 gold_assert(gsym->has_got_offset(got_type)); 4721 got_offset = gsym->got_offset(got_type) - target->got_size(); 4722 } 4723 else 4724 { 4725 unsigned int r_sym = elfcpp::elf_r_sym<size>(rela.get_r_info()); 4726 gold_assert(object->local_has_got_offset(r_sym, got_type)); 4727 got_offset = (object->local_got_offset(r_sym, got_type) 4728 - target->got_size()); 4729 } 4730 if (optimized_type == tls::TLSOPT_TO_IE) 4731 { 4732 value = target->got_plt_section()->address() + got_offset; 4733 this->tls_gd_to_ie(relinfo, relnum, rela, r_type, 4734 value, view, address, view_size); 4735 break; 4736 } 4737 else if (optimized_type == tls::TLSOPT_NONE) 4738 { 4739 // Relocate the field with the offset of the pair of GOT 4740 // entries. 4741 value = target->got_plt_section()->address() + got_offset; 4742 Relocate_functions<size, false>::pcrela32(view, value, addend, 4743 address); 4744 break; 4745 } 4746 } 4747 gold_error_at_location(relinfo, relnum, rela.get_r_offset(), 4748 _("unsupported reloc %u"), r_type); 4749 break; 4750 4751 case elfcpp::R_X86_64_GOTPC32_TLSDESC: // Global-dynamic (from ~oliva url) 4752 case elfcpp::R_X86_64_CODE_4_GOTPC32_TLSDESC: 4753 case elfcpp::R_X86_64_TLSDESC_CALL: 4754 if (!is_executable && optimized_type == tls::TLSOPT_TO_LE) 4755 { 4756 // See above comment for R_X86_64_TLSGD. 4757 optimized_type = tls::TLSOPT_NONE; 4758 } 4759 if (optimized_type == tls::TLSOPT_TO_LE) 4760 { 4761 if (tls_segment == NULL) 4762 { 4763 gold_assert(parameters->errors()->error_count() > 0 4764 || issue_undefined_symbol_error(gsym)); 4765 return; 4766 } 4767 this->tls_desc_gd_to_le(relinfo, relnum, tls_segment, 4768 rela, r_type, value, view, 4769 view_size); 4770 break; 4771 } 4772 else 4773 { 4774 unsigned int got_type = (optimized_type == tls::TLSOPT_TO_IE 4775 ? GOT_TYPE_TLS_OFFSET 4776 : GOT_TYPE_TLS_DESC); 4777 unsigned int got_offset = 0; 4778 if ((r_type == elfcpp::R_X86_64_GOTPC32_TLSDESC 4779 || r_type == elfcpp::R_X86_64_CODE_4_GOTPC32_TLSDESC) 4780 && optimized_type == tls::TLSOPT_NONE) 4781 { 4782 // We created GOT entries in the .got.tlsdesc portion of 4783 // the .got.plt section, but the offset stored in the 4784 // symbol is the offset within .got.tlsdesc. 4785 got_offset = (target->got_size() 4786 + target->got_plt_section()->data_size()); 4787 } 4788 if (gsym != NULL) 4789 { 4790 gold_assert(gsym->has_got_offset(got_type)); 4791 got_offset += gsym->got_offset(got_type) - target->got_size(); 4792 } 4793 else 4794 { 4795 unsigned int r_sym = elfcpp::elf_r_sym<size>(rela.get_r_info()); 4796 gold_assert(object->local_has_got_offset(r_sym, got_type)); 4797 got_offset += (object->local_got_offset(r_sym, got_type) 4798 - target->got_size()); 4799 } 4800 if (optimized_type == tls::TLSOPT_TO_IE) 4801 { 4802 value = target->got_plt_section()->address() + got_offset; 4803 this->tls_desc_gd_to_ie(relinfo, relnum, 4804 rela, r_type, value, view, address, 4805 view_size); 4806 break; 4807 } 4808 else if (optimized_type == tls::TLSOPT_NONE) 4809 { 4810 if (r_type == elfcpp::R_X86_64_GOTPC32_TLSDESC 4811 || r_type == elfcpp::R_X86_64_CODE_4_GOTPC32_TLSDESC) 4812 { 4813 // Relocate the field with the offset of the pair of GOT 4814 // entries. 4815 value = target->got_plt_section()->address() + got_offset; 4816 Relocate_functions<size, false>::pcrela32(view, value, addend, 4817 address); 4818 } 4819 break; 4820 } 4821 } 4822 gold_error_at_location(relinfo, relnum, rela.get_r_offset(), 4823 _("unsupported reloc %u"), r_type); 4824 break; 4825 4826 case elfcpp::R_X86_64_TLSLD: // Local-dynamic 4827 if (!is_executable && optimized_type == tls::TLSOPT_TO_LE) 4828 { 4829 // See above comment for R_X86_64_TLSGD. 4830 optimized_type = tls::TLSOPT_NONE; 4831 } 4832 if (optimized_type == tls::TLSOPT_TO_LE) 4833 { 4834 if (tls_segment == NULL) 4835 { 4836 gold_assert(parameters->errors()->error_count() > 0 4837 || issue_undefined_symbol_error(gsym)); 4838 return; 4839 } 4840 this->tls_ld_to_le(relinfo, relnum, tls_segment, rela, r_type, 4841 value, view, view_size); 4842 break; 4843 } 4844 else if (optimized_type == tls::TLSOPT_NONE) 4845 { 4846 // Relocate the field with the offset of the GOT entry for 4847 // the module index. 4848 unsigned int got_offset; 4849 got_offset = (target->got_mod_index_entry(NULL, NULL, NULL) 4850 - target->got_size()); 4851 value = target->got_plt_section()->address() + got_offset; 4852 Relocate_functions<size, false>::pcrela32(view, value, addend, 4853 address); 4854 break; 4855 } 4856 gold_error_at_location(relinfo, relnum, rela.get_r_offset(), 4857 _("unsupported reloc %u"), r_type); 4858 break; 4859 4860 case elfcpp::R_X86_64_DTPOFF32: 4861 // This relocation type is used in debugging information. 4862 // In that case we need to not optimize the value. If the 4863 // section is not executable, then we assume we should not 4864 // optimize this reloc. See comments above for R_X86_64_TLSGD, 4865 // R_X86_64_GOTPC32_TLSDESC, R_X86_64_TLSDESC_CALL, and 4866 // R_X86_64_TLSLD. 4867 if (optimized_type == tls::TLSOPT_TO_LE && is_executable) 4868 { 4869 if (tls_segment == NULL) 4870 { 4871 gold_assert(parameters->errors()->error_count() > 0 4872 || issue_undefined_symbol_error(gsym)); 4873 return; 4874 } 4875 value -= tls_segment->memsz(); 4876 } 4877 Relocate_functions<size, false>::rela32(view, value, addend); 4878 break; 4879 4880 case elfcpp::R_X86_64_DTPOFF64: 4881 // See R_X86_64_DTPOFF32, just above, for why we check for is_executable. 4882 if (optimized_type == tls::TLSOPT_TO_LE && is_executable) 4883 { 4884 if (tls_segment == NULL) 4885 { 4886 gold_assert(parameters->errors()->error_count() > 0 4887 || issue_undefined_symbol_error(gsym)); 4888 return; 4889 } 4890 value -= tls_segment->memsz(); 4891 } 4892 Relocate_functions<size, false>::rela64(view, value, addend); 4893 break; 4894 4895 case elfcpp::R_X86_64_GOTTPOFF: // Initial-exec 4896 case elfcpp::R_X86_64_CODE_4_GOTTPOFF: 4897 if (gsym != NULL 4898 && gsym->is_undefined() 4899 && parameters->options().output_is_executable()) 4900 { 4901 Target_x86_64<size>::Relocate::tls_ie_to_le(relinfo, relnum, 4902 NULL, rela, 4903 r_type, value, view, 4904 view_size); 4905 break; 4906 } 4907 else if (optimized_type == tls::TLSOPT_TO_LE) 4908 { 4909 if (tls_segment == NULL) 4910 { 4911 gold_assert(parameters->errors()->error_count() > 0 4912 || issue_undefined_symbol_error(gsym)); 4913 return; 4914 } 4915 Target_x86_64<size>::Relocate::tls_ie_to_le(relinfo, relnum, 4916 tls_segment, rela, 4917 r_type, value, view, 4918 view_size); 4919 break; 4920 } 4921 else if (optimized_type == tls::TLSOPT_NONE) 4922 { 4923 // Relocate the field with the offset of the GOT entry for 4924 // the tp-relative offset of the symbol. 4925 unsigned int got_offset; 4926 if (gsym != NULL) 4927 { 4928 gold_assert(gsym->has_got_offset(GOT_TYPE_TLS_OFFSET)); 4929 got_offset = (gsym->got_offset(GOT_TYPE_TLS_OFFSET) 4930 - target->got_size()); 4931 } 4932 else 4933 { 4934 unsigned int r_sym = elfcpp::elf_r_sym<size>(rela.get_r_info()); 4935 gold_assert(object->local_has_got_offset(r_sym, 4936 GOT_TYPE_TLS_OFFSET)); 4937 got_offset = (object->local_got_offset(r_sym, GOT_TYPE_TLS_OFFSET) 4938 - target->got_size()); 4939 } 4940 value = target->got_plt_section()->address() + got_offset; 4941 Relocate_functions<size, false>::pcrela32(view, value, addend, 4942 address); 4943 break; 4944 } 4945 gold_error_at_location(relinfo, relnum, rela.get_r_offset(), 4946 _("unsupported reloc type %u"), 4947 r_type); 4948 break; 4949 4950 case elfcpp::R_X86_64_TPOFF32: // Local-exec 4951 if (tls_segment == NULL) 4952 { 4953 gold_assert(parameters->errors()->error_count() > 0 4954 || issue_undefined_symbol_error(gsym)); 4955 return; 4956 } 4957 value -= tls_segment->memsz(); 4958 Relocate_functions<size, false>::rela32(view, value, addend); 4959 break; 4960 } 4961 } 4962 4963 // Do a relocation in which we convert a TLS General-Dynamic to an 4964 // Initial-Exec. 4965 4966 template<int size> 4967 inline void 4968 Target_x86_64<size>::Relocate::tls_gd_to_ie( 4969 const Relocate_info<size, false>* relinfo, 4970 size_t relnum, 4971 const elfcpp::Rela<size, false>& rela, 4972 unsigned int, 4973 typename elfcpp::Elf_types<size>::Elf_Addr value, 4974 unsigned char* view, 4975 typename elfcpp::Elf_types<size>::Elf_Addr address, 4976 section_size_type view_size) 4977 { 4978 // For SIZE == 64: 4979 // .byte 0x66; leaq foo@tlsgd(%rip),%rdi; 4980 // .word 0x6666; rex64; call __tls_get_addr@PLT 4981 // ==> movq %fs:0,%rax; addq x@gottpoff(%rip),%rax 4982 // .byte 0x66; leaq foo@tlsgd(%rip),%rdi; 4983 // .word 0x66; rex64; call *__tls_get_addr@GOTPCREL(%rip) 4984 // ==> movq %fs:0,%rax; addq x@gottpoff(%rip),%rax 4985 // For SIZE == 32: 4986 // leaq foo@tlsgd(%rip),%rdi; 4987 // .word 0x6666; rex64; call __tls_get_addr@PLT 4988 // ==> movl %fs:0,%eax; addq x@gottpoff(%rip),%rax 4989 // leaq foo@tlsgd(%rip),%rdi; 4990 // .word 0x66; rex64; call *__tls_get_addr@GOTPCREL(%rip) 4991 // ==> movl %fs:0,%eax; addq x@gottpoff(%rip),%rax 4992 4993 tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, 12); 4994 tls::check_tls(relinfo, relnum, rela.get_r_offset(), 4995 (memcmp(view + 4, "\x66\x66\x48\xe8", 4) == 0 4996 || memcmp(view + 4, "\x66\x48\xff", 3) == 0)); 4997 4998 if (size == 64) 4999 { 5000 tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, 5001 -4); 5002 tls::check_tls(relinfo, relnum, rela.get_r_offset(), 5003 (memcmp(view - 4, "\x66\x48\x8d\x3d", 4) == 0)); 5004 memcpy(view - 4, "\x64\x48\x8b\x04\x25\0\0\0\0\x48\x03\x05\0\0\0\0", 5005 16); 5006 } 5007 else 5008 { 5009 tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, 5010 -3); 5011 tls::check_tls(relinfo, relnum, rela.get_r_offset(), 5012 (memcmp(view - 3, "\x48\x8d\x3d", 3) == 0)); 5013 memcpy(view - 3, "\x64\x8b\x04\x25\0\0\0\0\x48\x03\x05\0\0\0\0", 5014 15); 5015 } 5016 5017 const elfcpp::Elf_Xword addend = rela.get_r_addend(); 5018 Relocate_functions<size, false>::pcrela32(view + 8, value, addend - 8, 5019 address); 5020 5021 // The next reloc should be a PLT32 reloc against __tls_get_addr. 5022 // We can skip it. 5023 this->skip_call_tls_get_addr_ = true; 5024 } 5025 5026 // Do a relocation in which we convert a TLS General-Dynamic to a 5027 // Local-Exec. 5028 5029 template<int size> 5030 inline void 5031 Target_x86_64<size>::Relocate::tls_gd_to_le( 5032 const Relocate_info<size, false>* relinfo, 5033 size_t relnum, 5034 Output_segment* tls_segment, 5035 const elfcpp::Rela<size, false>& rela, 5036 unsigned int, 5037 typename elfcpp::Elf_types<size>::Elf_Addr value, 5038 unsigned char* view, 5039 section_size_type view_size) 5040 { 5041 // For SIZE == 64: 5042 // .byte 0x66; leaq foo@tlsgd(%rip),%rdi; 5043 // .word 0x6666; rex64; call __tls_get_addr@PLT 5044 // ==> movq %fs:0,%rax; leaq x@tpoff(%rax),%rax 5045 // .byte 0x66; leaq foo@tlsgd(%rip),%rdi; 5046 // .word 0x66; rex64; call *__tls_get_addr@GOTPCREL(%rip) 5047 // ==> movq %fs:0,%rax; leaq x@tpoff(%rax),%rax 5048 // For SIZE == 32: 5049 // leaq foo@tlsgd(%rip),%rdi; 5050 // .word 0x6666; rex64; call __tls_get_addr@PLT 5051 // ==> movl %fs:0,%eax; leaq x@tpoff(%rax),%rax 5052 // leaq foo@tlsgd(%rip),%rdi; 5053 // .word 0x66; rex64; call *__tls_get_addr@GOTPCREL(%rip) 5054 // ==> movl %fs:0,%eax; leaq x@tpoff(%rax),%rax 5055 5056 tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, 12); 5057 tls::check_tls(relinfo, relnum, rela.get_r_offset(), 5058 (memcmp(view + 4, "\x66\x66\x48\xe8", 4) == 0 5059 || memcmp(view + 4, "\x66\x48\xff", 3) == 0)); 5060 5061 if (size == 64) 5062 { 5063 tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, 5064 -4); 5065 tls::check_tls(relinfo, relnum, rela.get_r_offset(), 5066 (memcmp(view - 4, "\x66\x48\x8d\x3d", 4) == 0)); 5067 memcpy(view - 4, "\x64\x48\x8b\x04\x25\0\0\0\0\x48\x8d\x80\0\0\0\0", 5068 16); 5069 } 5070 else 5071 { 5072 tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, 5073 -3); 5074 tls::check_tls(relinfo, relnum, rela.get_r_offset(), 5075 (memcmp(view - 3, "\x48\x8d\x3d", 3) == 0)); 5076 5077 memcpy(view - 3, "\x64\x8b\x04\x25\0\0\0\0\x48\x8d\x80\0\0\0\0", 5078 15); 5079 } 5080 5081 value -= tls_segment->memsz(); 5082 Relocate_functions<size, false>::rela32(view + 8, value, 0); 5083 5084 // The next reloc should be a PLT32 reloc against __tls_get_addr. 5085 // We can skip it. 5086 this->skip_call_tls_get_addr_ = true; 5087 } 5088 5089 // Do a TLSDESC-style General-Dynamic to Initial-Exec transition. 5090 5091 template<int size> 5092 inline void 5093 Target_x86_64<size>::Relocate::tls_desc_gd_to_ie( 5094 const Relocate_info<size, false>* relinfo, 5095 size_t relnum, 5096 const elfcpp::Rela<size, false>& rela, 5097 unsigned int r_type, 5098 typename elfcpp::Elf_types<size>::Elf_Addr value, 5099 unsigned char* view, 5100 typename elfcpp::Elf_types<size>::Elf_Addr address, 5101 section_size_type view_size) 5102 { 5103 if (r_type == elfcpp::R_X86_64_GOTPC32_TLSDESC 5104 || r_type == elfcpp::R_X86_64_CODE_4_GOTPC32_TLSDESC) 5105 { 5106 // LP64: leaq foo@tlsdesc(%rip), %rax 5107 // ==> movq foo@gottpoff(%rip), %rax 5108 // X32: rex leal foo@tlsdesc(%rip), %eax 5109 // ==> rex movl foo@gottpoff(%rip), %eax 5110 tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, -3); 5111 tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, 4); 5112 tls::check_tls(relinfo, relnum, rela.get_r_offset(), 5113 ((r_type == elfcpp::R_X86_64_CODE_4_GOTPC32_TLSDESC 5114 || (view[-3] & 0xfb) == 0x48 5115 || (size == 32 && (view[-3] & 0xfb) == 0x40)) 5116 && view[-2] == 0x8d 5117 && (view[-1] & 0xc7) == 0x05)); 5118 view[-2] = 0x8b; 5119 const elfcpp::Elf_Xword addend = rela.get_r_addend(); 5120 Relocate_functions<size, false>::pcrela32(view, value, addend, address); 5121 } 5122 else 5123 { 5124 // LP64: call *foo@tlscall(%rax) 5125 // ==> xchg %ax, %ax 5126 // X32: call *foo@tlscall(%eax) 5127 // ==> nopl (%rax) 5128 gold_assert(r_type == elfcpp::R_X86_64_TLSDESC_CALL); 5129 tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, 2); 5130 int prefix = 0; 5131 if (size == 32 && view[0] == 0x67) 5132 { 5133 tls::check_range(relinfo, relnum, rela.get_r_offset(), 5134 view_size, 3); 5135 prefix = 1; 5136 } 5137 tls::check_tls(relinfo, relnum, rela.get_r_offset(), 5138 view[prefix] == 0xff && view[prefix + 1] == 0x10); 5139 if (prefix) 5140 { 5141 view[0] = 0x0f; 5142 view[1] = 0x1f; 5143 view[2] = 0x00; 5144 } 5145 else 5146 { 5147 view[0] = 0x66; 5148 view[1] = 0x90; 5149 } 5150 } 5151 } 5152 5153 // Do a TLSDESC-style General-Dynamic to Local-Exec transition. 5154 5155 template<int size> 5156 inline void 5157 Target_x86_64<size>::Relocate::tls_desc_gd_to_le( 5158 const Relocate_info<size, false>* relinfo, 5159 size_t relnum, 5160 Output_segment* tls_segment, 5161 const elfcpp::Rela<size, false>& rela, 5162 unsigned int r_type, 5163 typename elfcpp::Elf_types<size>::Elf_Addr value, 5164 unsigned char* view, 5165 section_size_type view_size) 5166 { 5167 if (r_type == elfcpp::R_X86_64_GOTPC32_TLSDESC) 5168 { 5169 // LP64: leaq foo@tlsdesc(%rip), %rax 5170 // ==> movq foo@tpoff, %rax 5171 // X32: rex leal foo@tlsdesc(%rip), %eax 5172 // ==> rex movl foo@tpoff, %eax 5173 tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, -3); 5174 tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, 4); 5175 tls::check_tls(relinfo, relnum, rela.get_r_offset(), 5176 (((view[-3] & 0xfb) == 0x48 5177 || (size == 32 && (view[-3] & 0xfb) == 0x40)) 5178 && view[-2] == 0x8d 5179 && (view[-1] & 0xc7) == 0x05)); 5180 view[-3] = (view[-3] & 0x48) | ((view[-3] >> 2) & 1); 5181 view[-2] = 0xc7; 5182 view[-1] = 0xc0 | ((view[-1] >> 3) & 7); 5183 value -= tls_segment->memsz(); 5184 Relocate_functions<size, false>::rela32(view, value, 0); 5185 } 5186 else if (r_type == elfcpp::R_X86_64_CODE_4_GOTPC32_TLSDESC) 5187 { 5188 // REX2: lea foo@tlsdesc(%rip), %reg 5189 // ==> mov foo@tpoff, %reg 5190 tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, -3); 5191 tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, 4); 5192 tls::check_tls(relinfo, relnum, rela.get_r_offset(), 5193 (view[-2] == 0x8d 5194 && (view[-1] & 0xc7) == 0x05)); 5195 unsigned char rex2_mask = 4 | 4 << 4; 5196 view[-3] = (view[-3] & ~rex2_mask) | ((view[-3] & rex2_mask) >> 2); 5197 view[-2] = 0xc7; 5198 view[-1] = 0xc0 | ((view[-1] >> 3) & 7); 5199 value -= tls_segment->memsz(); 5200 Relocate_functions<size, false>::rela32(view, value, 0); 5201 } 5202 else 5203 { 5204 // LP64: call *foo@tlscall(%rax) 5205 // ==> xchg %ax, %ax 5206 // X32: call *foo@tlscall(%eax) 5207 // ==> nopl (%rax) 5208 gold_assert(r_type == elfcpp::R_X86_64_TLSDESC_CALL); 5209 tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, 2); 5210 int prefix = 0; 5211 if (size == 32 && view[0] == 0x67) 5212 { 5213 tls::check_range(relinfo, relnum, rela.get_r_offset(), 5214 view_size, 3); 5215 prefix = 1; 5216 } 5217 tls::check_tls(relinfo, relnum, rela.get_r_offset(), 5218 view[prefix] == 0xff && view[prefix + 1] == 0x10); 5219 if (prefix) 5220 { 5221 view[0] = 0x0f; 5222 view[1] = 0x1f; 5223 view[2] = 0x00; 5224 } 5225 else 5226 { 5227 view[0] = 0x66; 5228 view[1] = 0x90; 5229 } 5230 } 5231 } 5232 5233 template<int size> 5234 inline void 5235 Target_x86_64<size>::Relocate::tls_ld_to_le( 5236 const Relocate_info<size, false>* relinfo, 5237 size_t relnum, 5238 Output_segment*, 5239 const elfcpp::Rela<size, false>& rela, 5240 unsigned int, 5241 typename elfcpp::Elf_types<size>::Elf_Addr, 5242 unsigned char* view, 5243 section_size_type view_size) 5244 { 5245 // leaq foo@tlsld(%rip),%rdi; call __tls_get_addr@plt; 5246 // For SIZE == 64: 5247 // ... leq foo@dtpoff(%rax),%reg 5248 // ==> .word 0x6666; .byte 0x66; movq %fs:0,%rax ... leaq x@tpoff(%rax),%rdx 5249 // For SIZE == 32: 5250 // ... leq foo@dtpoff(%rax),%reg 5251 // ==> nopl 0x0(%rax); movl %fs:0,%eax ... leaq x@tpoff(%rax),%rdx 5252 // leaq foo@tlsld(%rip),%rdi; call *__tls_get_addr@GOTPCREL(%rip) 5253 // For SIZE == 64: 5254 // ... leq foo@dtpoff(%rax),%reg 5255 // ==> .word 0x6666; .byte 0x6666; movq %fs:0,%rax ... leaq x@tpoff(%rax),%rdx 5256 // For SIZE == 32: 5257 // ... leq foo@dtpoff(%rax),%reg 5258 // ==> nopw 0x0(%rax); movl %fs:0,%eax ... leaq x@tpoff(%rax),%rdx 5259 5260 tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, -3); 5261 tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, 9); 5262 5263 tls::check_tls(relinfo, relnum, rela.get_r_offset(), 5264 view[-3] == 0x48 && view[-2] == 0x8d && view[-1] == 0x3d); 5265 5266 tls::check_tls(relinfo, relnum, rela.get_r_offset(), 5267 view[4] == 0xe8 || view[4] == 0xff); 5268 5269 if (view[4] == 0xe8) 5270 { 5271 if (size == 64) 5272 memcpy(view - 3, "\x66\x66\x66\x64\x48\x8b\x04\x25\0\0\0\0", 12); 5273 else 5274 memcpy(view - 3, "\x0f\x1f\x40\x00\x64\x8b\x04\x25\0\0\0\0", 12); 5275 } 5276 else 5277 { 5278 if (size == 64) 5279 memcpy(view - 3, "\x66\x66\x66\x66\x64\x48\x8b\x04\x25\0\0\0\0", 5280 13); 5281 else 5282 memcpy(view - 3, "\x66\x0f\x1f\x40\x00\x64\x8b\x04\x25\0\0\0\0", 5283 13); 5284 } 5285 5286 // The next reloc should be a PLT32 reloc against __tls_get_addr. 5287 // We can skip it. 5288 this->skip_call_tls_get_addr_ = true; 5289 } 5290 5291 // Do a relocation in which we convert a TLS Initial-Exec to a 5292 // Local-Exec. 5293 5294 template<int size> 5295 inline void 5296 Target_x86_64<size>::Relocate::tls_ie_to_le( 5297 const Relocate_info<size, false>* relinfo, 5298 size_t relnum, 5299 Output_segment* tls_segment, 5300 const elfcpp::Rela<size, false>& rela, 5301 unsigned int r_type, 5302 typename elfcpp::Elf_types<size>::Elf_Addr value, 5303 unsigned char* view, 5304 section_size_type view_size) 5305 { 5306 // We need to examine the opcodes to figure out which instruction we 5307 // are looking at. 5308 5309 // movq foo@gottpoff(%rip),%reg ==> movq $YY,%reg 5310 // addq foo@gottpoff(%rip),%reg ==> addq $YY,%reg 5311 5312 tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, -3); 5313 tls::check_range(relinfo, relnum, rela.get_r_offset(), view_size, 4); 5314 5315 unsigned char op1 = view[-3]; 5316 unsigned char op2 = view[-2]; 5317 unsigned char op3 = view[-1]; 5318 unsigned char reg = op3 >> 3; 5319 5320 if (r_type == elfcpp::R_X86_64_GOTTPOFF) 5321 { 5322 if (op2 == 0x8b) 5323 { 5324 // movq 5325 if (op1 == 0x4c) 5326 view[-3] = 0x49; 5327 else if (size == 32 && op1 == 0x44) 5328 view[-3] = 0x41; 5329 view[-2] = 0xc7; 5330 view[-1] = 0xc0 | reg; 5331 } 5332 else if (reg == 4) 5333 { 5334 // Special handling for %rsp. 5335 if (op1 == 0x4c) 5336 view[-3] = 0x49; 5337 else if (size == 32 && op1 == 0x44) 5338 view[-3] = 0x41; 5339 view[-2] = 0x81; 5340 view[-1] = 0xc0 | reg; 5341 } 5342 else 5343 { 5344 // addq 5345 if (op1 == 0x4c) 5346 view[-3] = 0x4d; 5347 else if (size == 32 && op1 == 0x44) 5348 view[-3] = 0x45; 5349 view[-2] = 0x8d; 5350 view[-1] = 0x80 | reg | (reg << 3); 5351 } 5352 } 5353 else 5354 { 5355 if (op2 == 0x8b) 5356 op2 = 0xc7; 5357 else 5358 op2 = 0x81; 5359 5360 unsigned char rex2_mask = 4 | 4 << 4; 5361 view[-3] = (view[-3] & ~rex2_mask) | ((view[-3] & rex2_mask) >> 2); 5362 view[-2] = op2; 5363 view[-1] = 0xc0 | reg; 5364 } 5365 5366 if (tls_segment != NULL) 5367 value -= tls_segment->memsz(); 5368 Relocate_functions<size, false>::rela32(view, value, 0); 5369 } 5370 5371 // Relocate section data. 5372 5373 template<int size> 5374 void 5375 Target_x86_64<size>::relocate_section( 5376 const Relocate_info<size, false>* relinfo, 5377 unsigned int sh_type, 5378 const unsigned char* prelocs, 5379 size_t reloc_count, 5380 Output_section* output_section, 5381 bool needs_special_offset_handling, 5382 unsigned char* view, 5383 typename elfcpp::Elf_types<size>::Elf_Addr address, 5384 section_size_type view_size, 5385 const Reloc_symbol_changes* reloc_symbol_changes) 5386 { 5387 typedef gold::Default_classify_reloc<elfcpp::SHT_RELA, size, false> 5388 Classify_reloc; 5389 5390 gold_assert(sh_type == elfcpp::SHT_RELA); 5391 5392 gold::relocate_section<size, false, Target_x86_64<size>, Relocate, 5393 gold::Default_comdat_behavior, Classify_reloc>( 5394 relinfo, 5395 this, 5396 prelocs, 5397 reloc_count, 5398 output_section, 5399 needs_special_offset_handling, 5400 view, 5401 address, 5402 view_size, 5403 reloc_symbol_changes); 5404 } 5405 5406 // Apply an incremental relocation. Incremental relocations always refer 5407 // to global symbols. 5408 5409 template<int size> 5410 void 5411 Target_x86_64<size>::apply_relocation( 5412 const Relocate_info<size, false>* relinfo, 5413 typename elfcpp::Elf_types<size>::Elf_Addr r_offset, 5414 unsigned int r_type, 5415 typename elfcpp::Elf_types<size>::Elf_Swxword r_addend, 5416 const Symbol* gsym, 5417 unsigned char* view, 5418 typename elfcpp::Elf_types<size>::Elf_Addr address, 5419 section_size_type view_size) 5420 { 5421 gold::apply_relocation<size, false, Target_x86_64<size>, 5422 typename Target_x86_64<size>::Relocate>( 5423 relinfo, 5424 this, 5425 r_offset, 5426 r_type, 5427 r_addend, 5428 gsym, 5429 view, 5430 address, 5431 view_size); 5432 } 5433 5434 // Scan the relocs during a relocatable link. 5435 5436 template<int size> 5437 void 5438 Target_x86_64<size>::scan_relocatable_relocs( 5439 Symbol_table* symtab, 5440 Layout* layout, 5441 Sized_relobj_file<size, false>* object, 5442 unsigned int data_shndx, 5443 unsigned int sh_type, 5444 const unsigned char* prelocs, 5445 size_t reloc_count, 5446 Output_section* output_section, 5447 bool needs_special_offset_handling, 5448 size_t local_symbol_count, 5449 const unsigned char* plocal_symbols, 5450 Relocatable_relocs* rr) 5451 { 5452 typedef gold::Default_classify_reloc<elfcpp::SHT_RELA, size, false> 5453 Classify_reloc; 5454 typedef gold::Default_scan_relocatable_relocs<Classify_reloc> 5455 Scan_relocatable_relocs; 5456 5457 gold_assert(sh_type == elfcpp::SHT_RELA); 5458 5459 gold::scan_relocatable_relocs<size, false, Scan_relocatable_relocs>( 5460 symtab, 5461 layout, 5462 object, 5463 data_shndx, 5464 prelocs, 5465 reloc_count, 5466 output_section, 5467 needs_special_offset_handling, 5468 local_symbol_count, 5469 plocal_symbols, 5470 rr); 5471 } 5472 5473 // Scan the relocs for --emit-relocs. 5474 5475 template<int size> 5476 void 5477 Target_x86_64<size>::emit_relocs_scan( 5478 Symbol_table* symtab, 5479 Layout* layout, 5480 Sized_relobj_file<size, false>* object, 5481 unsigned int data_shndx, 5482 unsigned int sh_type, 5483 const unsigned char* prelocs, 5484 size_t reloc_count, 5485 Output_section* output_section, 5486 bool needs_special_offset_handling, 5487 size_t local_symbol_count, 5488 const unsigned char* plocal_syms, 5489 Relocatable_relocs* rr) 5490 { 5491 typedef gold::Default_classify_reloc<elfcpp::SHT_RELA, size, false> 5492 Classify_reloc; 5493 typedef gold::Default_emit_relocs_strategy<Classify_reloc> 5494 Emit_relocs_strategy; 5495 5496 gold_assert(sh_type == elfcpp::SHT_RELA); 5497 5498 gold::scan_relocatable_relocs<size, false, Emit_relocs_strategy>( 5499 symtab, 5500 layout, 5501 object, 5502 data_shndx, 5503 prelocs, 5504 reloc_count, 5505 output_section, 5506 needs_special_offset_handling, 5507 local_symbol_count, 5508 plocal_syms, 5509 rr); 5510 } 5511 5512 // Relocate a section during a relocatable link. 5513 5514 template<int size> 5515 void 5516 Target_x86_64<size>::relocate_relocs( 5517 const Relocate_info<size, false>* relinfo, 5518 unsigned int sh_type, 5519 const unsigned char* prelocs, 5520 size_t reloc_count, 5521 Output_section* output_section, 5522 typename elfcpp::Elf_types<size>::Elf_Off offset_in_output_section, 5523 unsigned char* view, 5524 typename elfcpp::Elf_types<size>::Elf_Addr view_address, 5525 section_size_type view_size, 5526 unsigned char* reloc_view, 5527 section_size_type reloc_view_size) 5528 { 5529 typedef gold::Default_classify_reloc<elfcpp::SHT_RELA, size, false> 5530 Classify_reloc; 5531 5532 gold_assert(sh_type == elfcpp::SHT_RELA); 5533 5534 gold::relocate_relocs<size, false, Classify_reloc>( 5535 relinfo, 5536 prelocs, 5537 reloc_count, 5538 output_section, 5539 offset_in_output_section, 5540 view, 5541 view_address, 5542 view_size, 5543 reloc_view, 5544 reloc_view_size); 5545 } 5546 5547 // Return the value to use for a dynamic which requires special 5548 // treatment. This is how we support equality comparisons of function 5549 // pointers across shared library boundaries, as described in the 5550 // processor specific ABI supplement. 5551 5552 template<int size> 5553 uint64_t 5554 Target_x86_64<size>::do_dynsym_value(const Symbol* gsym) const 5555 { 5556 gold_assert(gsym->is_from_dynobj() && gsym->has_plt_offset()); 5557 return this->plt_address_for_global(gsym); 5558 } 5559 5560 // Return a string used to fill a code section with nops to take up 5561 // the specified length. 5562 5563 template<int size> 5564 std::string 5565 Target_x86_64<size>::do_code_fill(section_size_type length) const 5566 { 5567 if (length >= 16) 5568 { 5569 // Build a jmpq instruction to skip over the bytes. 5570 unsigned char jmp[5]; 5571 jmp[0] = 0xe9; 5572 elfcpp::Swap_unaligned<32, false>::writeval(jmp + 1, length - 5); 5573 return (std::string(reinterpret_cast<char*>(&jmp[0]), 5) 5574 + std::string(length - 5, static_cast<char>(0x90))); 5575 } 5576 5577 // Nop sequences of various lengths. 5578 const char nop1[1] = { '\x90' }; // nop 5579 const char nop2[2] = { '\x66', '\x90' }; // xchg %ax %ax 5580 const char nop3[3] = { '\x0f', '\x1f', '\x00' }; // nop (%rax) 5581 const char nop4[4] = { '\x0f', '\x1f', '\x40', // nop 0(%rax) 5582 '\x00'}; 5583 const char nop5[5] = { '\x0f', '\x1f', '\x44', // nop 0(%rax,%rax,1) 5584 '\x00', '\x00' }; 5585 const char nop6[6] = { '\x66', '\x0f', '\x1f', // nopw 0(%rax,%rax,1) 5586 '\x44', '\x00', '\x00' }; 5587 const char nop7[7] = { '\x0f', '\x1f', '\x80', // nopl 0L(%rax) 5588 '\x00', '\x00', '\x00', 5589 '\x00' }; 5590 const char nop8[8] = { '\x0f', '\x1f', '\x84', // nopl 0L(%rax,%rax,1) 5591 '\x00', '\x00', '\x00', 5592 '\x00', '\x00' }; 5593 const char nop9[9] = { '\x66', '\x0f', '\x1f', // nopw 0L(%rax,%rax,1) 5594 '\x84', '\x00', '\x00', 5595 '\x00', '\x00', '\x00' }; 5596 const char nop10[10] = { '\x66', '\x2e', '\x0f', // nopw %cs:0L(%rax,%rax,1) 5597 '\x1f', '\x84', '\x00', 5598 '\x00', '\x00', '\x00', 5599 '\x00' }; 5600 const char nop11[11] = { '\x66', '\x66', '\x2e', // data16 5601 '\x0f', '\x1f', '\x84', // nopw %cs:0L(%rax,%rax,1) 5602 '\x00', '\x00', '\x00', 5603 '\x00', '\x00' }; 5604 const char nop12[12] = { '\x66', '\x66', '\x66', // data16; data16 5605 '\x2e', '\x0f', '\x1f', // nopw %cs:0L(%rax,%rax,1) 5606 '\x84', '\x00', '\x00', 5607 '\x00', '\x00', '\x00' }; 5608 const char nop13[13] = { '\x66', '\x66', '\x66', // data16; data16; data16 5609 '\x66', '\x2e', '\x0f', // nopw %cs:0L(%rax,%rax,1) 5610 '\x1f', '\x84', '\x00', 5611 '\x00', '\x00', '\x00', 5612 '\x00' }; 5613 const char nop14[14] = { '\x66', '\x66', '\x66', // data16; data16; data16 5614 '\x66', '\x66', '\x2e', // data16 5615 '\x0f', '\x1f', '\x84', // nopw %cs:0L(%rax,%rax,1) 5616 '\x00', '\x00', '\x00', 5617 '\x00', '\x00' }; 5618 const char nop15[15] = { '\x66', '\x66', '\x66', // data16; data16; data16 5619 '\x66', '\x66', '\x66', // data16; data16 5620 '\x2e', '\x0f', '\x1f', // nopw %cs:0L(%rax,%rax,1) 5621 '\x84', '\x00', '\x00', 5622 '\x00', '\x00', '\x00' }; 5623 5624 const char* nops[16] = { 5625 NULL, 5626 nop1, nop2, nop3, nop4, nop5, nop6, nop7, 5627 nop8, nop9, nop10, nop11, nop12, nop13, nop14, nop15 5628 }; 5629 5630 return std::string(nops[length], length); 5631 } 5632 5633 // Return the addend to use for a target specific relocation. The 5634 // only target specific relocation is R_X86_64_TLSDESC for a local 5635 // symbol. We want to set the addend is the offset of the local 5636 // symbol in the TLS segment. 5637 5638 template<int size> 5639 uint64_t 5640 Target_x86_64<size>::do_reloc_addend(void* arg, unsigned int r_type, 5641 uint64_t) const 5642 { 5643 gold_assert(r_type == elfcpp::R_X86_64_TLSDESC); 5644 uintptr_t intarg = reinterpret_cast<uintptr_t>(arg); 5645 gold_assert(intarg < this->tlsdesc_reloc_info_.size()); 5646 const Tlsdesc_info& ti(this->tlsdesc_reloc_info_[intarg]); 5647 const Symbol_value<size>* psymval = ti.object->local_symbol(ti.r_sym); 5648 gold_assert(psymval->is_tls_symbol()); 5649 // The value of a TLS symbol is the offset in the TLS segment. 5650 return psymval->value(ti.object, 0); 5651 } 5652 5653 // Return the value to use for the base of a DW_EH_PE_datarel offset 5654 // in an FDE. Solaris and SVR4 use DW_EH_PE_datarel because their 5655 // assembler can not write out the difference between two labels in 5656 // different sections, so instead of using a pc-relative value they 5657 // use an offset from the GOT. 5658 5659 template<int size> 5660 uint64_t 5661 Target_x86_64<size>::do_ehframe_datarel_base() const 5662 { 5663 gold_assert(this->global_offset_table_ != NULL); 5664 Symbol* sym = this->global_offset_table_; 5665 Sized_symbol<size>* ssym = static_cast<Sized_symbol<size>*>(sym); 5666 return ssym->value(); 5667 } 5668 5669 // FNOFFSET in section SHNDX in OBJECT is the start of a function 5670 // compiled with -fsplit-stack. The function calls non-split-stack 5671 // code. We have to change the function so that it always ensures 5672 // that it has enough stack space to run some random function. 5673 5674 static const unsigned char cmp_insn_32[] = { 0x64, 0x3b, 0x24, 0x25 }; 5675 static const unsigned char lea_r10_insn_32[] = { 0x44, 0x8d, 0x94, 0x24 }; 5676 static const unsigned char lea_r11_insn_32[] = { 0x44, 0x8d, 0x9c, 0x24 }; 5677 5678 static const unsigned char cmp_insn_64[] = { 0x64, 0x48, 0x3b, 0x24, 0x25 }; 5679 static const unsigned char lea_r10_insn_64[] = { 0x4c, 0x8d, 0x94, 0x24 }; 5680 static const unsigned char lea_r11_insn_64[] = { 0x4c, 0x8d, 0x9c, 0x24 }; 5681 5682 template<int size> 5683 void 5684 Target_x86_64<size>::do_calls_non_split(Relobj* object, unsigned int shndx, 5685 section_offset_type fnoffset, 5686 section_size_type fnsize, 5687 const unsigned char*, 5688 size_t, 5689 unsigned char* view, 5690 section_size_type view_size, 5691 std::string* from, 5692 std::string* to) const 5693 { 5694 const char* const cmp_insn = reinterpret_cast<const char*> 5695 (size == 32 ? cmp_insn_32 : cmp_insn_64); 5696 const char* const lea_r10_insn = reinterpret_cast<const char*> 5697 (size == 32 ? lea_r10_insn_32 : lea_r10_insn_64); 5698 const char* const lea_r11_insn = reinterpret_cast<const char*> 5699 (size == 32 ? lea_r11_insn_32 : lea_r11_insn_64); 5700 5701 const size_t cmp_insn_len = 5702 (size == 32 ? sizeof(cmp_insn_32) : sizeof(cmp_insn_64)); 5703 const size_t lea_r10_insn_len = 5704 (size == 32 ? sizeof(lea_r10_insn_32) : sizeof(lea_r10_insn_64)); 5705 const size_t lea_r11_insn_len = 5706 (size == 32 ? sizeof(lea_r11_insn_32) : sizeof(lea_r11_insn_64)); 5707 const size_t nop_len = (size == 32 ? 7 : 8); 5708 5709 // The function starts with a comparison of the stack pointer and a 5710 // field in the TCB. This is followed by a jump. 5711 5712 // cmp %fs:NN,%rsp 5713 if (this->match_view(view, view_size, fnoffset, cmp_insn, cmp_insn_len) 5714 && fnsize > nop_len + 1) 5715 { 5716 // We will call __morestack if the carry flag is set after this 5717 // comparison. We turn the comparison into an stc instruction 5718 // and some nops. 5719 view[fnoffset] = '\xf9'; 5720 this->set_view_to_nop(view, view_size, fnoffset + 1, nop_len); 5721 } 5722 // lea NN(%rsp),%r10 5723 // lea NN(%rsp),%r11 5724 else if ((this->match_view(view, view_size, fnoffset, 5725 lea_r10_insn, lea_r10_insn_len) 5726 || this->match_view(view, view_size, fnoffset, 5727 lea_r11_insn, lea_r11_insn_len)) 5728 && fnsize > 8) 5729 { 5730 // This is loading an offset from the stack pointer for a 5731 // comparison. The offset is negative, so we decrease the 5732 // offset by the amount of space we need for the stack. This 5733 // means we will avoid calling __morestack if there happens to 5734 // be plenty of space on the stack already. 5735 unsigned char* pval = view + fnoffset + 4; 5736 uint32_t val = elfcpp::Swap_unaligned<32, false>::readval(pval); 5737 val -= parameters->options().split_stack_adjust_size(); 5738 elfcpp::Swap_unaligned<32, false>::writeval(pval, val); 5739 } 5740 else 5741 { 5742 if (!object->has_no_split_stack()) 5743 object->error(_("failed to match split-stack sequence at " 5744 "section %u offset %0zx"), 5745 shndx, static_cast<size_t>(fnoffset)); 5746 return; 5747 } 5748 5749 // We have to change the function so that it calls 5750 // __morestack_non_split instead of __morestack. The former will 5751 // allocate additional stack space. 5752 *from = "__morestack"; 5753 *to = "__morestack_non_split"; 5754 } 5755 5756 // The selector for x86_64 object files. Note this is never instantiated 5757 // directly. It's only used in Target_selector_x86_64_nacl, below. 5758 5759 template<int size> 5760 class Target_selector_x86_64 : public Target_selector_freebsd 5761 { 5762 public: 5763 Target_selector_x86_64() 5764 : Target_selector_freebsd(elfcpp::EM_X86_64, size, false, 5765 (size == 64 5766 ? "elf64-x86-64" : "elf32-x86-64"), 5767 (size == 64 5768 ? "elf64-x86-64-freebsd" 5769 : "elf32-x86-64-freebsd"), 5770 (size == 64 ? "elf_x86_64" : "elf32_x86_64")) 5771 { } 5772 5773 Target* 5774 do_instantiate_target() 5775 { return new Target_x86_64<size>(); } 5776 5777 }; 5778 5779 // NaCl variant. It uses different PLT contents. 5780 5781 template<int size> 5782 class Output_data_plt_x86_64_nacl : public Output_data_plt_x86_64<size> 5783 { 5784 public: 5785 Output_data_plt_x86_64_nacl(Layout* layout, 5786 Output_data_got<64, false>* got, 5787 Output_data_got_plt_x86_64* got_plt, 5788 Output_data_space* got_irelative) 5789 : Output_data_plt_x86_64<size>(layout, plt_entry_size, 5790 got, got_plt, got_irelative) 5791 { } 5792 5793 Output_data_plt_x86_64_nacl(Layout* layout, 5794 Output_data_got<64, false>* got, 5795 Output_data_got_plt_x86_64* got_plt, 5796 Output_data_space* got_irelative, 5797 unsigned int plt_count) 5798 : Output_data_plt_x86_64<size>(layout, plt_entry_size, 5799 got, got_plt, got_irelative, 5800 plt_count) 5801 { } 5802 5803 protected: 5804 virtual unsigned int 5805 do_get_plt_entry_size() const 5806 { return plt_entry_size; } 5807 5808 virtual void 5809 do_add_eh_frame(Layout* layout) 5810 { 5811 layout->add_eh_frame_for_plt(this, 5812 this->plt_eh_frame_cie, 5813 this->plt_eh_frame_cie_size, 5814 plt_eh_frame_fde, 5815 plt_eh_frame_fde_size); 5816 } 5817 5818 virtual void 5819 do_fill_first_plt_entry(unsigned char* pov, 5820 typename elfcpp::Elf_types<size>::Elf_Addr got_addr, 5821 typename elfcpp::Elf_types<size>::Elf_Addr plt_addr); 5822 5823 virtual unsigned int 5824 do_fill_plt_entry(unsigned char* pov, 5825 typename elfcpp::Elf_types<size>::Elf_Addr got_address, 5826 typename elfcpp::Elf_types<size>::Elf_Addr plt_address, 5827 unsigned int got_offset, 5828 unsigned int plt_offset, 5829 unsigned int plt_index); 5830 5831 virtual void 5832 do_fill_tlsdesc_entry(unsigned char* pov, 5833 typename elfcpp::Elf_types<size>::Elf_Addr got_address, 5834 typename elfcpp::Elf_types<size>::Elf_Addr plt_address, 5835 typename elfcpp::Elf_types<size>::Elf_Addr got_base, 5836 unsigned int tlsdesc_got_offset, 5837 unsigned int plt_offset); 5838 5839 private: 5840 // The size of an entry in the PLT. 5841 static const int plt_entry_size = 64; 5842 5843 // The first entry in the PLT. 5844 static const unsigned char first_plt_entry[plt_entry_size]; 5845 5846 // Other entries in the PLT for an executable. 5847 static const unsigned char plt_entry[plt_entry_size]; 5848 5849 // The reserved TLSDESC entry in the PLT for an executable. 5850 static const unsigned char tlsdesc_plt_entry[plt_entry_size]; 5851 5852 // The .eh_frame unwind information for the PLT. 5853 static const int plt_eh_frame_fde_size = 32; 5854 static const unsigned char plt_eh_frame_fde[plt_eh_frame_fde_size]; 5855 }; 5856 5857 template<int size> 5858 class Target_x86_64_nacl : public Target_x86_64<size> 5859 { 5860 public: 5861 Target_x86_64_nacl() 5862 : Target_x86_64<size>(&x86_64_nacl_info) 5863 { } 5864 5865 virtual Output_data_plt_x86_64<size>* 5866 do_make_data_plt(Layout* layout, 5867 Output_data_got<64, false>* got, 5868 Output_data_got_plt_x86_64* got_plt, 5869 Output_data_space* got_irelative) 5870 { 5871 return new Output_data_plt_x86_64_nacl<size>(layout, got, got_plt, 5872 got_irelative); 5873 } 5874 5875 virtual Output_data_plt_x86_64<size>* 5876 do_make_data_plt(Layout* layout, 5877 Output_data_got<64, false>* got, 5878 Output_data_got_plt_x86_64* got_plt, 5879 Output_data_space* got_irelative, 5880 unsigned int plt_count) 5881 { 5882 return new Output_data_plt_x86_64_nacl<size>(layout, got, got_plt, 5883 got_irelative, 5884 plt_count); 5885 } 5886 5887 virtual std::string 5888 do_code_fill(section_size_type length) const; 5889 5890 private: 5891 static const Target::Target_info x86_64_nacl_info; 5892 }; 5893 5894 template<> 5895 const Target::Target_info Target_x86_64_nacl<64>::x86_64_nacl_info = 5896 { 5897 64, // size 5898 false, // is_big_endian 5899 elfcpp::EM_X86_64, // machine_code 5900 false, // has_make_symbol 5901 false, // has_resolve 5902 true, // has_code_fill 5903 true, // is_default_stack_executable 5904 true, // can_icf_inline_merge_sections 5905 '\0', // wrap_char 5906 "/lib64/ld-nacl-x86-64.so.1", // dynamic_linker 5907 0x20000, // default_text_segment_address 5908 0x10000, // abi_pagesize (overridable by -z max-page-size) 5909 0x10000, // common_pagesize (overridable by -z common-page-size) 5910 true, // isolate_execinstr 5911 0x10000000, // rosegment_gap 5912 elfcpp::SHN_UNDEF, // small_common_shndx 5913 elfcpp::SHN_X86_64_LCOMMON, // large_common_shndx 5914 0, // small_common_section_flags 5915 elfcpp::SHF_X86_64_LARGE, // large_common_section_flags 5916 NULL, // attributes_section 5917 NULL, // attributes_vendor 5918 "_start", // entry_symbol_name 5919 32, // hash_entry_size 5920 elfcpp::SHT_X86_64_UNWIND, // unwind_section_type 5921 }; 5922 5923 template<> 5924 const Target::Target_info Target_x86_64_nacl<32>::x86_64_nacl_info = 5925 { 5926 32, // size 5927 false, // is_big_endian 5928 elfcpp::EM_X86_64, // machine_code 5929 false, // has_make_symbol 5930 false, // has_resolve 5931 true, // has_code_fill 5932 true, // is_default_stack_executable 5933 true, // can_icf_inline_merge_sections 5934 '\0', // wrap_char 5935 "/lib/ld-nacl-x86-64.so.1", // dynamic_linker 5936 0x20000, // default_text_segment_address 5937 0x10000, // abi_pagesize (overridable by -z max-page-size) 5938 0x10000, // common_pagesize (overridable by -z common-page-size) 5939 true, // isolate_execinstr 5940 0x10000000, // rosegment_gap 5941 elfcpp::SHN_UNDEF, // small_common_shndx 5942 elfcpp::SHN_X86_64_LCOMMON, // large_common_shndx 5943 0, // small_common_section_flags 5944 elfcpp::SHF_X86_64_LARGE, // large_common_section_flags 5945 NULL, // attributes_section 5946 NULL, // attributes_vendor 5947 "_start", // entry_symbol_name 5948 32, // hash_entry_size 5949 elfcpp::SHT_X86_64_UNWIND, // unwind_section_type 5950 }; 5951 5952 #define NACLMASK 0xe0 // 32-byte alignment mask. 5953 5954 // The first entry in the PLT. 5955 5956 template<int size> 5957 const unsigned char 5958 Output_data_plt_x86_64_nacl<size>::first_plt_entry[plt_entry_size] = 5959 { 5960 0xff, 0x35, // pushq contents of memory address 5961 0, 0, 0, 0, // replaced with address of .got + 8 5962 0x4c, 0x8b, 0x1d, // mov GOT+16(%rip), %r11 5963 0, 0, 0, 0, // replaced with address of .got + 16 5964 0x41, 0x83, 0xe3, NACLMASK, // and $-32, %r11d 5965 0x4d, 0x01, 0xfb, // add %r15, %r11 5966 0x41, 0xff, 0xe3, // jmpq *%r11 5967 5968 // 9-byte nop sequence to pad out to the next 32-byte boundary. 5969 0x66, 0x0f, 0x1f, 0x84, 0, 0, 0, 0, 0, // nopw 0x0(%rax,%rax,1) 5970 5971 // 32 bytes of nop to pad out to the standard size 5972 0x66, 0x66, 0x66, 0x66, 0x66, 0x66, // excess data32 prefixes 5973 0x2e, 0x0f, 0x1f, 0x84, 0, 0, 0, 0, 0, // nopw %cs:0x0(%rax,%rax,1) 5974 0x66, 0x66, 0x66, 0x66, 0x66, 0x66, // excess data32 prefixes 5975 0x2e, 0x0f, 0x1f, 0x84, 0, 0, 0, 0, 0, // nopw %cs:0x0(%rax,%rax,1) 5976 0x66, // excess data32 prefix 5977 0x90 // nop 5978 }; 5979 5980 template<int size> 5981 void 5982 Output_data_plt_x86_64_nacl<size>::do_fill_first_plt_entry( 5983 unsigned char* pov, 5984 typename elfcpp::Elf_types<size>::Elf_Addr got_address, 5985 typename elfcpp::Elf_types<size>::Elf_Addr plt_address) 5986 { 5987 memcpy(pov, first_plt_entry, plt_entry_size); 5988 elfcpp::Swap_unaligned<32, false>::writeval(pov + 2, 5989 (got_address + 8 5990 - (plt_address + 2 + 4))); 5991 elfcpp::Swap_unaligned<32, false>::writeval(pov + 9, 5992 (got_address + 16 5993 - (plt_address + 9 + 4))); 5994 } 5995 5996 // Subsequent entries in the PLT. 5997 5998 template<int size> 5999 const unsigned char 6000 Output_data_plt_x86_64_nacl<size>::plt_entry[plt_entry_size] = 6001 { 6002 0x4c, 0x8b, 0x1d, // mov name@GOTPCREL(%rip),%r11 6003 0, 0, 0, 0, // replaced with address of symbol in .got 6004 0x41, 0x83, 0xe3, NACLMASK, // and $-32, %r11d 6005 0x4d, 0x01, 0xfb, // add %r15, %r11 6006 0x41, 0xff, 0xe3, // jmpq *%r11 6007 6008 // 15-byte nop sequence to pad out to the next 32-byte boundary. 6009 0x66, 0x66, 0x66, 0x66, 0x66, 0x66, // excess data32 prefixes 6010 0x2e, 0x0f, 0x1f, 0x84, 0, 0, 0, 0, 0, // nopw %cs:0x0(%rax,%rax,1) 6011 6012 // Lazy GOT entries point here (32-byte aligned). 6013 0x68, // pushq immediate 6014 0, 0, 0, 0, // replaced with index into relocation table 6015 0xe9, // jmp relative 6016 0, 0, 0, 0, // replaced with offset to start of .plt0 6017 6018 // 22 bytes of nop to pad out to the standard size. 6019 0x66, 0x66, 0x66, 0x66, 0x66, 0x66, // excess data32 prefixes 6020 0x2e, 0x0f, 0x1f, 0x84, 0, 0, 0, 0, 0, // nopw %cs:0x0(%rax,%rax,1) 6021 0x0f, 0x1f, 0x80, 0, 0, 0, 0, // nopl 0x0(%rax) 6022 }; 6023 6024 template<int size> 6025 unsigned int 6026 Output_data_plt_x86_64_nacl<size>::do_fill_plt_entry( 6027 unsigned char* pov, 6028 typename elfcpp::Elf_types<size>::Elf_Addr got_address, 6029 typename elfcpp::Elf_types<size>::Elf_Addr plt_address, 6030 unsigned int got_offset, 6031 unsigned int plt_offset, 6032 unsigned int plt_index) 6033 { 6034 memcpy(pov, plt_entry, plt_entry_size); 6035 elfcpp::Swap_unaligned<32, false>::writeval(pov + 3, 6036 (got_address + got_offset 6037 - (plt_address + plt_offset 6038 + 3 + 4))); 6039 6040 elfcpp::Swap_unaligned<32, false>::writeval(pov + 33, plt_index); 6041 elfcpp::Swap_unaligned<32, false>::writeval(pov + 38, 6042 - (plt_offset + 38 + 4)); 6043 6044 return 32; 6045 } 6046 6047 // The reserved TLSDESC entry in the PLT. 6048 6049 template<int size> 6050 const unsigned char 6051 Output_data_plt_x86_64_nacl<size>::tlsdesc_plt_entry[plt_entry_size] = 6052 { 6053 0xff, 0x35, // pushq x(%rip) 6054 0, 0, 0, 0, // replaced with address of linkmap GOT entry (at PLTGOT + 8) 6055 0x4c, 0x8b, 0x1d, // mov y(%rip),%r11 6056 0, 0, 0, 0, // replaced with offset of reserved TLSDESC_GOT entry 6057 0x41, 0x83, 0xe3, NACLMASK, // and $-32, %r11d 6058 0x4d, 0x01, 0xfb, // add %r15, %r11 6059 0x41, 0xff, 0xe3, // jmpq *%r11 6060 6061 // 41 bytes of nop to pad out to the standard size. 6062 0x66, 0x66, 0x66, 0x66, 0x66, 0x66, // excess data32 prefixes 6063 0x2e, 0x0f, 0x1f, 0x84, 0, 0, 0, 0, 0, // nopw %cs:0x0(%rax,%rax,1) 6064 0x66, 0x66, 0x66, 0x66, 0x66, 0x66, // excess data32 prefixes 6065 0x2e, 0x0f, 0x1f, 0x84, 0, 0, 0, 0, 0, // nopw %cs:0x0(%rax,%rax,1) 6066 0x66, 0x66, // excess data32 prefixes 6067 0x2e, 0x0f, 0x1f, 0x84, 0, 0, 0, 0, 0, // nopw %cs:0x0(%rax,%rax,1) 6068 }; 6069 6070 template<int size> 6071 void 6072 Output_data_plt_x86_64_nacl<size>::do_fill_tlsdesc_entry( 6073 unsigned char* pov, 6074 typename elfcpp::Elf_types<size>::Elf_Addr got_address, 6075 typename elfcpp::Elf_types<size>::Elf_Addr plt_address, 6076 typename elfcpp::Elf_types<size>::Elf_Addr got_base, 6077 unsigned int tlsdesc_got_offset, 6078 unsigned int plt_offset) 6079 { 6080 memcpy(pov, tlsdesc_plt_entry, plt_entry_size); 6081 elfcpp::Swap_unaligned<32, false>::writeval(pov + 2, 6082 (got_address + 8 6083 - (plt_address + plt_offset 6084 + 2 + 4))); 6085 elfcpp::Swap_unaligned<32, false>::writeval(pov + 9, 6086 (got_base 6087 + tlsdesc_got_offset 6088 - (plt_address + plt_offset 6089 + 9 + 4))); 6090 } 6091 6092 // The .eh_frame unwind information for the PLT. 6093 6094 template<int size> 6095 const unsigned char 6096 Output_data_plt_x86_64_nacl<size>::plt_eh_frame_fde[plt_eh_frame_fde_size] = 6097 { 6098 0, 0, 0, 0, // Replaced with offset to .plt. 6099 0, 0, 0, 0, // Replaced with size of .plt. 6100 0, // Augmentation size. 6101 elfcpp::DW_CFA_def_cfa_offset, 16, // DW_CFA_def_cfa_offset: 16. 6102 elfcpp::DW_CFA_advance_loc + 6, // Advance 6 to __PLT__ + 6. 6103 elfcpp::DW_CFA_def_cfa_offset, 24, // DW_CFA_def_cfa_offset: 24. 6104 elfcpp::DW_CFA_advance_loc + 58, // Advance 58 to __PLT__ + 64. 6105 elfcpp::DW_CFA_def_cfa_expression, // DW_CFA_def_cfa_expression. 6106 13, // Block length. 6107 elfcpp::DW_OP_breg7, 8, // Push %rsp + 8. 6108 elfcpp::DW_OP_breg16, 0, // Push %rip. 6109 elfcpp::DW_OP_const1u, 63, // Push 0x3f. 6110 elfcpp::DW_OP_and, // & (%rip & 0x3f). 6111 elfcpp::DW_OP_const1u, 37, // Push 0x25. 6112 elfcpp::DW_OP_ge, // >= ((%rip & 0x3f) >= 0x25) 6113 elfcpp::DW_OP_lit3, // Push 3. 6114 elfcpp::DW_OP_shl, // << (((%rip & 0x3f) >= 0x25) << 3) 6115 elfcpp::DW_OP_plus, // + ((((%rip&0x3f)>=0x25)<<3)+%rsp+8 6116 elfcpp::DW_CFA_nop, // Align to 32 bytes. 6117 elfcpp::DW_CFA_nop 6118 }; 6119 6120 // Return a string used to fill a code section with nops. 6121 // For NaCl, long NOPs are only valid if they do not cross 6122 // bundle alignment boundaries, so keep it simple with one-byte NOPs. 6123 template<int size> 6124 std::string 6125 Target_x86_64_nacl<size>::do_code_fill(section_size_type length) const 6126 { 6127 return std::string(length, static_cast<char>(0x90)); 6128 } 6129 6130 // The selector for x86_64-nacl object files. 6131 6132 template<int size> 6133 class Target_selector_x86_64_nacl 6134 : public Target_selector_nacl<Target_selector_x86_64<size>, 6135 Target_x86_64_nacl<size> > 6136 { 6137 public: 6138 Target_selector_x86_64_nacl() 6139 : Target_selector_nacl<Target_selector_x86_64<size>, 6140 Target_x86_64_nacl<size> >("x86-64", 6141 size == 64 6142 ? "elf64-x86-64-nacl" 6143 : "elf32-x86-64-nacl", 6144 size == 64 6145 ? "elf_x86_64_nacl" 6146 : "elf32_x86_64_nacl") 6147 { } 6148 }; 6149 6150 Target_selector_x86_64_nacl<64> target_selector_x86_64; 6151 Target_selector_x86_64_nacl<32> target_selector_x32; 6152 6153 } // End anonymous namespace. 6154