gdbserver/win32-i386-low.cc

   1 /* Copyright (C) 2007-2024 Free Software Foundation, Inc.
   2
   3    This file is part of GDB.
   4
   5    This program is free software; you can redistribute it and/or modify
   6    it under the terms of the GNU General Public License as published by
   7    the Free Software Foundation; either version 3 of the License, or
   8    (at your option) any later version.
   9
  10    This program is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13    GNU General Public License for more details.
  14
  15    You should have received a copy of the GNU General Public License
  16    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
  17
  18 #include "win32-low.h"
  19 #include "x86-low.h"
  20 #include "gdbsupport/x86-xstate.h"
  21 #ifdef __x86_64__
  22 #include "arch/amd64.h"
  23 #endif
  24 #include "arch/i386.h"
  25 #include "tdesc.h"
  26 #include "x86-tdesc.h"
  27
  28 using namespace windows_nat;
  29
  30 #ifndef CONTEXT_EXTENDED_REGISTERS
  31 #define CONTEXT_EXTENDED_REGISTERS 0
  32 #endif
  33
  34 #define I386_FISEG_REGNUM 27
  35 #define I386_FOP_REGNUM 31
  36
  37 #define I386_CS_REGNUM 10
  38 #define I386_GS_REGNUM 15
  39
  40 #define AMD64_FISEG_REGNUM 35
  41 #define AMD64_FOP_REGNUM 39
  42
  43 #define AMD64_CS_REGNUM 18
  44 #define AMD64_GS_REGNUM 23
  45
  46 #define FLAG_TRACE_BIT 0x100
  47
  48 static struct x86_debug_reg_state debug_reg_state;
  49
  50 static void
  51 update_debug_registers (thread_info *thread)
  52 {
  53   windows_thread_info *th = (windows_thread_info *) thread_target_data (thread);
  54
  55   /* The actual update is done later just before resuming the lwp,
  56      we just mark that the registers need updating.  */
  57   th->debug_registers_changed = true;
  58 }
  59
  60 /* Update the inferior's debug register REGNUM from STATE.  */
  61
  62 static void
  63 x86_dr_low_set_addr (int regnum, CORE_ADDR addr)
  64 {
  65   gdb_assert (DR_FIRSTADDR <= regnum && regnum <= DR_LASTADDR);
  66
  67   /* Only update the threads of this process.  */
  68   current_process ()->for_each_thread (update_debug_registers);
  69 }
  70
  71 /* Update the inferior's DR7 debug control register from STATE.  */
  72
  73 static void
  74 x86_dr_low_set_control (unsigned long control)
  75 {
  76   /* Only update the threads of this process.  */
  77   current_process ()->for_each_thread (update_debug_registers);
  78 }
  79
  80 /* Return the current value of a DR register of the current thread's
  81    context.  */
  82
  83 static DWORD64
  84 win32_get_current_dr (int dr)
  85 {
  86   windows_thread_info *th
  87     = (windows_thread_info *) thread_target_data (current_thread);
  88
  89   win32_require_context (th);
  90
  91 #ifdef __x86_64__
  92 #define RET_DR(DR)                              \
  93   case DR:                                      \
  94     return th->wow64_context.Dr ## DR
  95
  96   if (windows_process.wow64_process)
  97     {
  98       switch (dr)
  99         {
 100           RET_DR (0);
 101           RET_DR (1);
 102           RET_DR (2);
 103           RET_DR (3);
 104           RET_DR (6);
 105           RET_DR (7);
 106         }
 107     }
 108   else
 109 #undef RET_DR
 110 #endif
 111 #define RET_DR(DR)                              \
 112   case DR:                                      \
 113     return th->context.Dr ## DR
 114
 115     {
 116       switch (dr)
 117         {
 118           RET_DR (0);
 119           RET_DR (1);
 120           RET_DR (2);
 121           RET_DR (3);
 122           RET_DR (6);
 123           RET_DR (7);
 124         }
 125     }
 126
 127 #undef RET_DR
 128
 129   gdb_assert_not_reached ("unhandled dr");
 130 }
 131
 132 static CORE_ADDR
 133 x86_dr_low_get_addr (int regnum)
 134 {
 135   gdb_assert (DR_FIRSTADDR <= regnum && regnum <= DR_LASTADDR);
 136
 137   return win32_get_current_dr (regnum - DR_FIRSTADDR);
 138 }
 139
 140 static unsigned long
 141 x86_dr_low_get_control (void)
 142 {
 143   return win32_get_current_dr (7);
 144 }
 145
 146 /* Get the value of the DR6 debug status register from the inferior
 147    and record it in STATE.  */
 148
 149 static unsigned long
 150 x86_dr_low_get_status (void)
 151 {
 152   return win32_get_current_dr (6);
 153 }
 154
 155 /* Low-level function vector.  */
 156 struct x86_dr_low_type x86_dr_low =
 157   {
 158     x86_dr_low_set_control,
 159     x86_dr_low_set_addr,
 160     x86_dr_low_get_addr,
 161     x86_dr_low_get_status,
 162     x86_dr_low_get_control,
 163     sizeof (void *),
 164   };
 165
 166 /* Breakpoint/watchpoint support.  */
 167
 168 static int
 169 i386_supports_z_point_type (char z_type)
 170 {
 171   switch (z_type)
 172     {
 173     case Z_PACKET_HW_BP:
 174     case Z_PACKET_WRITE_WP:
 175     case Z_PACKET_ACCESS_WP:
 176       return 1;
 177     default:
 178       return 0;
 179     }
 180 }
 181
 182 static int
 183 i386_insert_point (enum raw_bkpt_type type, CORE_ADDR addr,
 184                    int size, struct raw_breakpoint *bp)
 185 {
 186   switch (type)
 187     {
 188     case raw_bkpt_type_hw:
 189     case raw_bkpt_type_write_wp:
 190     case raw_bkpt_type_access_wp:
 191       {
 192         enum target_hw_bp_type hw_type
 193           = raw_bkpt_type_to_target_hw_bp_type (type);
 194
 195         return x86_dr_insert_watchpoint (&debug_reg_state,
 196                                          hw_type, addr, size);
 197       }
 198     default:
 199       /* Unsupported.  */
 200       return 1;
 201     }
 202 }
 203
 204 static int
 205 i386_remove_point (enum raw_bkpt_type type, CORE_ADDR addr,
 206                    int size, struct raw_breakpoint *bp)
 207 {
 208   switch (type)
 209     {
 210     case raw_bkpt_type_hw:
 211     case raw_bkpt_type_write_wp:
 212     case raw_bkpt_type_access_wp:
 213       {
 214         enum target_hw_bp_type hw_type
 215           = raw_bkpt_type_to_target_hw_bp_type (type);
 216
 217         return x86_dr_remove_watchpoint (&debug_reg_state,
 218                                          hw_type, addr, size);
 219       }
 220     default:
 221       /* Unsupported.  */
 222       return 1;
 223     }
 224 }
 225
 226 static int
 227 x86_stopped_by_watchpoint (void)
 228 {
 229   return x86_dr_stopped_by_watchpoint (&debug_reg_state);
 230 }
 231
 232 static CORE_ADDR
 233 x86_stopped_data_address (void)
 234 {
 235   CORE_ADDR addr;
 236   if (x86_dr_stopped_data_address (&debug_reg_state, &addr))
 237     return addr;
 238   return 0;
 239 }
 240
 241 static void
 242 i386_initial_stuff (void)
 243 {
 244   x86_low_init_dregs (&debug_reg_state);
 245 }
 246
 247 static void
 248 i386_get_thread_context (windows_thread_info *th)
 249 {
 250   /* Requesting the CONTEXT_EXTENDED_REGISTERS register set fails if
 251      the system doesn't support extended registers.  */
 252   static DWORD extended_registers = CONTEXT_EXTENDED_REGISTERS;
 253
 254  again:
 255 #ifdef __x86_64__
 256   if (windows_process.wow64_process)
 257     th->wow64_context.ContextFlags = (CONTEXT_FULL
 258                                       | CONTEXT_FLOATING_POINT
 259                                       | CONTEXT_DEBUG_REGISTERS
 260                                       | extended_registers);
 261   else
 262 #endif
 263     th->context.ContextFlags = (CONTEXT_FULL
 264                                 | CONTEXT_FLOATING_POINT
 265                                 | CONTEXT_DEBUG_REGISTERS
 266                                 | extended_registers);
 267
 268   BOOL ret;
 269 #ifdef __x86_64__
 270   if (windows_process.wow64_process)
 271     ret = Wow64GetThreadContext (th->h, &th->wow64_context);
 272   else
 273 #endif
 274     ret = GetThreadContext (th->h, &th->context);
 275   if (!ret)
 276     {
 277       DWORD e = GetLastError ();
 278
 279       if (extended_registers && e == ERROR_INVALID_PARAMETER)
 280         {
 281           extended_registers = 0;
 282           goto again;
 283         }
 284
 285       error ("GetThreadContext failure %ld\n", (long) e);
 286     }
 287 }
 288
 289 static void
 290 i386_prepare_to_resume (windows_thread_info *th)
 291 {
 292   if (th->debug_registers_changed)
 293     {
 294       struct x86_debug_reg_state *dr = &debug_reg_state;
 295
 296       win32_require_context (th);
 297
 298 #ifdef __x86_64__
 299       if (windows_process.wow64_process)
 300         {
 301           th->wow64_context.Dr0 = dr->dr_mirror[0];
 302           th->wow64_context.Dr1 = dr->dr_mirror[1];
 303           th->wow64_context.Dr2 = dr->dr_mirror[2];
 304           th->wow64_context.Dr3 = dr->dr_mirror[3];
 305           /* th->wow64_context.Dr6 = dr->dr_status_mirror;
 306              FIXME: should we set dr6 also ?? */
 307           th->wow64_context.Dr7 = dr->dr_control_mirror;
 308         }
 309       else
 310 #endif
 311         {
 312           th->context.Dr0 = dr->dr_mirror[0];
 313           th->context.Dr1 = dr->dr_mirror[1];
 314           th->context.Dr2 = dr->dr_mirror[2];
 315           th->context.Dr3 = dr->dr_mirror[3];
 316           /* th->context.Dr6 = dr->dr_status_mirror;
 317              FIXME: should we set dr6 also ?? */
 318           th->context.Dr7 = dr->dr_control_mirror;
 319         }
 320
 321       th->debug_registers_changed = false;
 322     }
 323 }
 324
 325 static void
 326 i386_thread_added (windows_thread_info *th)
 327 {
 328   th->debug_registers_changed = true;
 329 }
 330
 331 static void
 332 i386_single_step (windows_thread_info *th)
 333 {
 334 #ifdef __x86_64__
 335   if (windows_process.wow64_process)
 336     th->wow64_context.EFlags |= FLAG_TRACE_BIT;
 337   else
 338 #endif
 339     th->context.EFlags |= FLAG_TRACE_BIT;
 340 }
 341
 342 /* An array of offset mappings into a Win32 Context structure.
 343    This is a one-to-one mapping which is indexed by gdb's register
 344    numbers.  It retrieves an offset into the context structure where
 345    the 4 byte register is located.
 346    An offset value of -1 indicates that Win32 does not provide this
 347    register in it's CONTEXT structure.  In this case regptr will return
 348    a pointer into a dummy register.  */
 349 #ifdef __x86_64__
 350 #define context_offset(x) (offsetof (WOW64_CONTEXT, x))
 351 #else
 352 #define context_offset(x) ((int)&(((CONTEXT *)NULL)->x))
 353 #endif
 354 static const int i386_mappings[] = {
 355   context_offset (Eax),
 356   context_offset (Ecx),
 357   context_offset (Edx),
 358   context_offset (Ebx),
 359   context_offset (Esp),
 360   context_offset (Ebp),
 361   context_offset (Esi),
 362   context_offset (Edi),
 363   context_offset (Eip),
 364   context_offset (EFlags),
 365   context_offset (SegCs),
 366   context_offset (SegSs),
 367   context_offset (SegDs),
 368   context_offset (SegEs),
 369   context_offset (SegFs),
 370   context_offset (SegGs),
 371   context_offset (FloatSave.RegisterArea[0 * 10]),
 372   context_offset (FloatSave.RegisterArea[1 * 10]),
 373   context_offset (FloatSave.RegisterArea[2 * 10]),
 374   context_offset (FloatSave.RegisterArea[3 * 10]),
 375   context_offset (FloatSave.RegisterArea[4 * 10]),
 376   context_offset (FloatSave.RegisterArea[5 * 10]),
 377   context_offset (FloatSave.RegisterArea[6 * 10]),
 378   context_offset (FloatSave.RegisterArea[7 * 10]),
 379   context_offset (FloatSave.ControlWord),
 380   context_offset (FloatSave.StatusWord),
 381   context_offset (FloatSave.TagWord),
 382   context_offset (FloatSave.ErrorSelector),
 383   context_offset (FloatSave.ErrorOffset),
 384   context_offset (FloatSave.DataSelector),
 385   context_offset (FloatSave.DataOffset),
 386   context_offset (FloatSave.ErrorSelector),
 387   /* XMM0-7 */
 388   context_offset (ExtendedRegisters[10 * 16]),
 389   context_offset (ExtendedRegisters[11 * 16]),
 390   context_offset (ExtendedRegisters[12 * 16]),
 391   context_offset (ExtendedRegisters[13 * 16]),
 392   context_offset (ExtendedRegisters[14 * 16]),
 393   context_offset (ExtendedRegisters[15 * 16]),
 394   context_offset (ExtendedRegisters[16 * 16]),
 395   context_offset (ExtendedRegisters[17 * 16]),
 396   /* MXCSR */
 397   context_offset (ExtendedRegisters[24])
 398 };
 399 #undef context_offset
 400
 401 #ifdef __x86_64__
 402
 403 #define context_offset(x) (offsetof (CONTEXT, x))
 404 static const int amd64_mappings[] =
 405 {
 406   context_offset (Rax),
 407   context_offset (Rbx),
 408   context_offset (Rcx),
 409   context_offset (Rdx),
 410   context_offset (Rsi),
 411   context_offset (Rdi),
 412   context_offset (Rbp),
 413   context_offset (Rsp),
 414   context_offset (R8),
 415   context_offset (R9),
 416   context_offset (R10),
 417   context_offset (R11),
 418   context_offset (R12),
 419   context_offset (R13),
 420   context_offset (R14),
 421   context_offset (R15),
 422   context_offset (Rip),
 423   context_offset (EFlags),
 424   context_offset (SegCs),
 425   context_offset (SegSs),
 426   context_offset (SegDs),
 427   context_offset (SegEs),
 428   context_offset (SegFs),
 429   context_offset (SegGs),
 430   context_offset (FloatSave.FloatRegisters[0]),
 431   context_offset (FloatSave.FloatRegisters[1]),
 432   context_offset (FloatSave.FloatRegisters[2]),
 433   context_offset (FloatSave.FloatRegisters[3]),
 434   context_offset (FloatSave.FloatRegisters[4]),
 435   context_offset (FloatSave.FloatRegisters[5]),
 436   context_offset (FloatSave.FloatRegisters[6]),
 437   context_offset (FloatSave.FloatRegisters[7]),
 438   context_offset (FloatSave.ControlWord),
 439   context_offset (FloatSave.StatusWord),
 440   context_offset (FloatSave.TagWord),
 441   context_offset (FloatSave.ErrorSelector),
 442   context_offset (FloatSave.ErrorOffset),
 443   context_offset (FloatSave.DataSelector),
 444   context_offset (FloatSave.DataOffset),
 445   context_offset (FloatSave.ErrorSelector)
 446   /* XMM0-7 */ ,
 447   context_offset (Xmm0),
 448   context_offset (Xmm1),
 449   context_offset (Xmm2),
 450   context_offset (Xmm3),
 451   context_offset (Xmm4),
 452   context_offset (Xmm5),
 453   context_offset (Xmm6),
 454   context_offset (Xmm7),
 455   context_offset (Xmm8),
 456   context_offset (Xmm9),
 457   context_offset (Xmm10),
 458   context_offset (Xmm11),
 459   context_offset (Xmm12),
 460   context_offset (Xmm13),
 461   context_offset (Xmm14),
 462   context_offset (Xmm15),
 463   /* MXCSR */
 464   context_offset (FloatSave.MxCsr)
 465 };
 466 #undef context_offset
 467
 468 #endif /* __x86_64__ */
 469
 470 /* Return true if R is the FISEG register.  */
 471 static bool
 472 is_fiseg_register (int r)
 473 {
 474 #ifdef __x86_64__
 475   if (!windows_process.wow64_process)
 476     return r == AMD64_FISEG_REGNUM;
 477   else
 478 #endif
 479     return r == I386_FISEG_REGNUM;
 480 }
 481
 482 /* Return true if R is the FOP register.  */
 483 static bool
 484 is_fop_register (int r)
 485 {
 486 #ifdef __x86_64__
 487   if (!windows_process.wow64_process)
 488     return r == AMD64_FOP_REGNUM;
 489   else
 490 #endif
 491     return r == I386_FOP_REGNUM;
 492 }
 493
 494 /* Return true if R is a segment register.  */
 495 static bool
 496 is_segment_register (int r)
 497 {
 498 #ifdef __x86_64__
 499   if (!windows_process.wow64_process)
 500     return r >= AMD64_CS_REGNUM && r <= AMD64_GS_REGNUM;
 501   else
 502 #endif
 503     return r >= I386_CS_REGNUM && r <= I386_GS_REGNUM;
 504 }
 505
 506 /* Fetch register from gdbserver regcache data.  */
 507 static void
 508 i386_fetch_inferior_register (struct regcache *regcache,
 509                               windows_thread_info *th, int r)
 510 {
 511   const int *mappings;
 512 #ifdef __x86_64__
 513   if (!windows_process.wow64_process)
 514     mappings = amd64_mappings;
 515   else
 516 #endif
 517     mappings = i386_mappings;
 518
 519   char *context_offset;
 520 #ifdef __x86_64__
 521   if (windows_process.wow64_process)
 522     context_offset = (char *) &th->wow64_context + mappings[r];
 523   else
 524 #endif
 525     context_offset = (char *) &th->context + mappings[r];
 526
 527   /* GDB treats some registers as 32-bit, where they are in fact only
 528      16 bits long.  These cases must be handled specially to avoid
 529      reading extraneous bits from the context.  */
 530   if (is_fiseg_register (r) || is_segment_register (r))
 531     {
 532       gdb_byte bytes[4] = {};
 533       memcpy (bytes, context_offset, 2);
 534       supply_register (regcache, r, bytes);
 535     }
 536   else if (is_fop_register (r))
 537     {
 538       long l = (*((long *) context_offset) >> 16) & ((1 << 11) - 1);
 539       supply_register (regcache, r, (char *) &l);
 540     }
 541   else
 542     supply_register (regcache, r, context_offset);
 543 }
 544
 545 /* Store a new register value into the thread context of TH.  */
 546 static void
 547 i386_store_inferior_register (struct regcache *regcache,
 548                               windows_thread_info *th, int r)
 549 {
 550   const int *mappings;
 551 #ifdef __x86_64__
 552   if (!windows_process.wow64_process)
 553     mappings = amd64_mappings;
 554   else
 555 #endif
 556     mappings = i386_mappings;
 557
 558   char *context_offset;
 559 #ifdef __x86_64__
 560   if (windows_process.wow64_process)
 561     context_offset = (char *) &th->wow64_context + mappings[r];
 562   else
 563 #endif
 564     context_offset = (char *) &th->context + mappings[r];
 565
 566   /* GDB treats some registers as 32-bit, where they are in fact only
 567      16 bits long.  These cases must be handled specially to avoid
 568      overwriting other registers in the context.  */
 569   if (is_fiseg_register (r) || is_segment_register (r))
 570     {
 571       gdb_byte bytes[4];
 572       collect_register (regcache, r, bytes);
 573       memcpy (context_offset, bytes, 2);
 574     }
 575   else if (is_fop_register (r))
 576     {
 577       gdb_byte bytes[4];
 578       collect_register (regcache, r, bytes);
 579       /* The value of FOP occupies the top two bytes in the context,
 580          so write the two low-order bytes from the cache into the
 581          appropriate spot.  */
 582       memcpy (context_offset + 2, bytes, 2);
 583     }
 584   else
 585     collect_register (regcache, r, context_offset);
 586 }
 587
 588 static const unsigned char i386_win32_breakpoint = 0xcc;
 589 #define i386_win32_breakpoint_len 1
 590
 591 static void
 592 i386_arch_setup (void)
 593 {
 594   struct target_desc *tdesc;
 595
 596 #ifdef __x86_64__
 597   tdesc = amd64_create_target_description (X86_XSTATE_SSE_MASK, false,
 598                                            false, false);
 599   init_target_desc (tdesc, amd64_expedite_regs, WINDOWS_OSABI);
 600   win32_tdesc = tdesc;
 601 #endif
 602
 603   tdesc = i386_create_target_description (X86_XSTATE_SSE_MASK, false, false);
 604   init_target_desc (tdesc, i386_expedite_regs, WINDOWS_OSABI);
 605 #ifdef __x86_64__
 606   wow64_win32_tdesc = tdesc;
 607 #else
 608   win32_tdesc = tdesc;
 609 #endif
 610 }
 611
 612 /* Implement win32_target_ops "num_regs" method.  */
 613
 614 static int
 615 i386_win32_num_regs (void)
 616 {
 617   int num_regs;
 618 #ifdef __x86_64__
 619   if (!windows_process.wow64_process)
 620     num_regs = sizeof (amd64_mappings) / sizeof (amd64_mappings[0]);
 621   else
 622 #endif
 623     num_regs = sizeof (i386_mappings) / sizeof (i386_mappings[0]);
 624   return num_regs;
 625 }
 626
 627 /* Implement win32_target_ops "get_pc" method.  */
 628
 629 static CORE_ADDR
 630 i386_win32_get_pc (struct regcache *regcache)
 631 {
 632   bool use_64bit = register_size (regcache->tdesc, 0) == 8;
 633
 634   if (use_64bit)
 635     {
 636       uint64_t pc;
 637
 638       collect_register_by_name (regcache, "rip", &pc);
 639       return (CORE_ADDR) pc;
 640     }
 641   else
 642     {
 643       uint32_t pc;
 644
 645       collect_register_by_name (regcache, "eip", &pc);
 646       return (CORE_ADDR) pc;
 647     }
 648 }
 649
 650 /* Implement win32_target_ops "set_pc" method.  */
 651
 652 static void
 653 i386_win32_set_pc (struct regcache *regcache, CORE_ADDR pc)
 654 {
 655   bool use_64bit = register_size (regcache->tdesc, 0) == 8;
 656
 657   if (use_64bit)
 658     {
 659       uint64_t newpc = pc;
 660
 661       supply_register_by_name (regcache, "rip", &newpc);
 662     }
 663   else
 664     {
 665       uint32_t newpc = pc;
 666
 667       supply_register_by_name (regcache, "eip", &newpc);
 668     }
 669 }
 670
 671 struct win32_target_ops the_low_target = {
 672   i386_arch_setup,
 673   i386_win32_num_regs,
 674   i386_initial_stuff,
 675   i386_get_thread_context,
 676   i386_prepare_to_resume,
 677   i386_thread_added,
 678   i386_fetch_inferior_register,
 679   i386_store_inferior_register,
 680   i386_single_step,
 681   &i386_win32_breakpoint,
 682   i386_win32_breakpoint_len,
 683   1,
 684   i386_win32_get_pc,
 685   i386_win32_set_pc,
 686   i386_supports_z_point_type,
 687   i386_insert_point,
 688   i386_remove_point,
 689   x86_stopped_by_watchpoint,
 690   x86_stopped_data_address
 691 };