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 #ifdef __x86_64__
 254   static DWORD wow64_extended_registers = WOW64_CONTEXT_EXTENDED_REGISTERS;
 255 #endif
 256
 257  again:
 258 #ifdef __x86_64__
 259   if (windows_process.wow64_process)
 260     th->wow64_context.ContextFlags = (WOW64_CONTEXT_FULL
 261                                       | WOW64_CONTEXT_FLOATING_POINT
 262                                       | WOW64_CONTEXT_DEBUG_REGISTERS
 263                                       | wow64_extended_registers);
 264   else
 265 #endif
 266     th->context.ContextFlags = (CONTEXT_FULL
 267                                 | CONTEXT_FLOATING_POINT
 268                                 | CONTEXT_DEBUG_REGISTERS
 269                                 | extended_registers);
 270
 271   BOOL ret;
 272 #ifdef __x86_64__
 273   if (windows_process.wow64_process)
 274     ret = Wow64GetThreadContext (th->h, &th->wow64_context);
 275   else
 276 #endif
 277     ret = GetThreadContext (th->h, &th->context);
 278   if (!ret)
 279     {
 280       DWORD e = GetLastError ();
 281
 282 #ifdef __x86_64__
 283       if (windows_process.wow64_process)
 284         {
 285           if (wow64_extended_registers && e == ERROR_INVALID_PARAMETER)
 286             {
 287               wow64_extended_registers = 0;
 288               goto again;
 289             }
 290         }
 291       else
 292 #endif
 293         {
 294           if (extended_registers && e == ERROR_INVALID_PARAMETER)
 295             {
 296               extended_registers = 0;
 297               goto again;
 298             }
 299         }
 300
 301       error ("GetThreadContext failure %ld\n", (long) e);
 302     }
 303 }
 304
 305 static void
 306 i386_prepare_to_resume (windows_thread_info *th)
 307 {
 308   if (th->debug_registers_changed)
 309     {
 310       struct x86_debug_reg_state *dr = &debug_reg_state;
 311
 312       win32_require_context (th);
 313
 314 #ifdef __x86_64__
 315       if (windows_process.wow64_process)
 316         {
 317           th->wow64_context.Dr0 = dr->dr_mirror[0];
 318           th->wow64_context.Dr1 = dr->dr_mirror[1];
 319           th->wow64_context.Dr2 = dr->dr_mirror[2];
 320           th->wow64_context.Dr3 = dr->dr_mirror[3];
 321           /* th->wow64_context.Dr6 = dr->dr_status_mirror;
 322              FIXME: should we set dr6 also ?? */
 323           th->wow64_context.Dr7 = dr->dr_control_mirror;
 324         }
 325       else
 326 #endif
 327         {
 328           th->context.Dr0 = dr->dr_mirror[0];
 329           th->context.Dr1 = dr->dr_mirror[1];
 330           th->context.Dr2 = dr->dr_mirror[2];
 331           th->context.Dr3 = dr->dr_mirror[3];
 332           /* th->context.Dr6 = dr->dr_status_mirror;
 333              FIXME: should we set dr6 also ?? */
 334           th->context.Dr7 = dr->dr_control_mirror;
 335         }
 336
 337       th->debug_registers_changed = false;
 338     }
 339 }
 340
 341 static void
 342 i386_thread_added (windows_thread_info *th)
 343 {
 344   th->debug_registers_changed = true;
 345 }
 346
 347 static void
 348 i386_single_step (windows_thread_info *th)
 349 {
 350 #ifdef __x86_64__
 351   if (windows_process.wow64_process)
 352     th->wow64_context.EFlags |= FLAG_TRACE_BIT;
 353   else
 354 #endif
 355     th->context.EFlags |= FLAG_TRACE_BIT;
 356 }
 357
 358 /* An array of offset mappings into a Win32 Context structure.
 359    This is a one-to-one mapping which is indexed by gdb's register
 360    numbers.  It retrieves an offset into the context structure where
 361    the 4 byte register is located.
 362    An offset value of -1 indicates that Win32 does not provide this
 363    register in it's CONTEXT structure.  In this case regptr will return
 364    a pointer into a dummy register.  */
 365 #ifdef __x86_64__
 366 #define context_offset(x) (offsetof (WOW64_CONTEXT, x))
 367 #else
 368 #define context_offset(x) ((int)&(((CONTEXT *)NULL)->x))
 369 #endif
 370 static const int i386_mappings[] = {
 371   context_offset (Eax),
 372   context_offset (Ecx),
 373   context_offset (Edx),
 374   context_offset (Ebx),
 375   context_offset (Esp),
 376   context_offset (Ebp),
 377   context_offset (Esi),
 378   context_offset (Edi),
 379   context_offset (Eip),
 380   context_offset (EFlags),
 381   context_offset (SegCs),
 382   context_offset (SegSs),
 383   context_offset (SegDs),
 384   context_offset (SegEs),
 385   context_offset (SegFs),
 386   context_offset (SegGs),
 387   context_offset (FloatSave.RegisterArea[0 * 10]),
 388   context_offset (FloatSave.RegisterArea[1 * 10]),
 389   context_offset (FloatSave.RegisterArea[2 * 10]),
 390   context_offset (FloatSave.RegisterArea[3 * 10]),
 391   context_offset (FloatSave.RegisterArea[4 * 10]),
 392   context_offset (FloatSave.RegisterArea[5 * 10]),
 393   context_offset (FloatSave.RegisterArea[6 * 10]),
 394   context_offset (FloatSave.RegisterArea[7 * 10]),
 395   context_offset (FloatSave.ControlWord),
 396   context_offset (FloatSave.StatusWord),
 397   context_offset (FloatSave.TagWord),
 398   context_offset (FloatSave.ErrorSelector),
 399   context_offset (FloatSave.ErrorOffset),
 400   context_offset (FloatSave.DataSelector),
 401   context_offset (FloatSave.DataOffset),
 402   context_offset (FloatSave.ErrorSelector),
 403   /* XMM0-7 */
 404   context_offset (ExtendedRegisters[10 * 16]),
 405   context_offset (ExtendedRegisters[11 * 16]),
 406   context_offset (ExtendedRegisters[12 * 16]),
 407   context_offset (ExtendedRegisters[13 * 16]),
 408   context_offset (ExtendedRegisters[14 * 16]),
 409   context_offset (ExtendedRegisters[15 * 16]),
 410   context_offset (ExtendedRegisters[16 * 16]),
 411   context_offset (ExtendedRegisters[17 * 16]),
 412   /* MXCSR */
 413   context_offset (ExtendedRegisters[24])
 414 };
 415 #undef context_offset
 416
 417 #ifdef __x86_64__
 418
 419 #define context_offset(x) (offsetof (CONTEXT, x))
 420 static const int amd64_mappings[] =
 421 {
 422   context_offset (Rax),
 423   context_offset (Rbx),
 424   context_offset (Rcx),
 425   context_offset (Rdx),
 426   context_offset (Rsi),
 427   context_offset (Rdi),
 428   context_offset (Rbp),
 429   context_offset (Rsp),
 430   context_offset (R8),
 431   context_offset (R9),
 432   context_offset (R10),
 433   context_offset (R11),
 434   context_offset (R12),
 435   context_offset (R13),
 436   context_offset (R14),
 437   context_offset (R15),
 438   context_offset (Rip),
 439   context_offset (EFlags),
 440   context_offset (SegCs),
 441   context_offset (SegSs),
 442   context_offset (SegDs),
 443   context_offset (SegEs),
 444   context_offset (SegFs),
 445   context_offset (SegGs),
 446   context_offset (FloatSave.FloatRegisters[0]),
 447   context_offset (FloatSave.FloatRegisters[1]),
 448   context_offset (FloatSave.FloatRegisters[2]),
 449   context_offset (FloatSave.FloatRegisters[3]),
 450   context_offset (FloatSave.FloatRegisters[4]),
 451   context_offset (FloatSave.FloatRegisters[5]),
 452   context_offset (FloatSave.FloatRegisters[6]),
 453   context_offset (FloatSave.FloatRegisters[7]),
 454   context_offset (FloatSave.ControlWord),
 455   context_offset (FloatSave.StatusWord),
 456   context_offset (FloatSave.TagWord),
 457   context_offset (FloatSave.ErrorSelector),
 458   context_offset (FloatSave.ErrorOffset),
 459   context_offset (FloatSave.DataSelector),
 460   context_offset (FloatSave.DataOffset),
 461   context_offset (FloatSave.ErrorSelector)
 462   /* XMM0-7 */ ,
 463   context_offset (Xmm0),
 464   context_offset (Xmm1),
 465   context_offset (Xmm2),
 466   context_offset (Xmm3),
 467   context_offset (Xmm4),
 468   context_offset (Xmm5),
 469   context_offset (Xmm6),
 470   context_offset (Xmm7),
 471   context_offset (Xmm8),
 472   context_offset (Xmm9),
 473   context_offset (Xmm10),
 474   context_offset (Xmm11),
 475   context_offset (Xmm12),
 476   context_offset (Xmm13),
 477   context_offset (Xmm14),
 478   context_offset (Xmm15),
 479   /* MXCSR */
 480   context_offset (FloatSave.MxCsr)
 481 };
 482 #undef context_offset
 483
 484 #endif /* __x86_64__ */
 485
 486 /* Return true if R is the FISEG register.  */
 487 static bool
 488 is_fiseg_register (int r)
 489 {
 490 #ifdef __x86_64__
 491   if (!windows_process.wow64_process)
 492     return r == AMD64_FISEG_REGNUM;
 493   else
 494 #endif
 495     return r == I386_FISEG_REGNUM;
 496 }
 497
 498 /* Return true if R is the FOP register.  */
 499 static bool
 500 is_fop_register (int r)
 501 {
 502 #ifdef __x86_64__
 503   if (!windows_process.wow64_process)
 504     return r == AMD64_FOP_REGNUM;
 505   else
 506 #endif
 507     return r == I386_FOP_REGNUM;
 508 }
 509
 510 /* Return true if R is a segment register.  */
 511 static bool
 512 is_segment_register (int r)
 513 {
 514 #ifdef __x86_64__
 515   if (!windows_process.wow64_process)
 516     return r >= AMD64_CS_REGNUM && r <= AMD64_GS_REGNUM;
 517   else
 518 #endif
 519     return r >= I386_CS_REGNUM && r <= I386_GS_REGNUM;
 520 }
 521
 522 /* Fetch register from gdbserver regcache data.  */
 523 static void
 524 i386_fetch_inferior_register (struct regcache *regcache,
 525                               windows_thread_info *th, int r)
 526 {
 527   const int *mappings;
 528 #ifdef __x86_64__
 529   if (!windows_process.wow64_process)
 530     mappings = amd64_mappings;
 531   else
 532 #endif
 533     mappings = i386_mappings;
 534
 535   char *context_offset;
 536 #ifdef __x86_64__
 537   if (windows_process.wow64_process)
 538     context_offset = (char *) &th->wow64_context + mappings[r];
 539   else
 540 #endif
 541     context_offset = (char *) &th->context + mappings[r];
 542
 543   /* GDB treats some registers as 32-bit, where they are in fact only
 544      16 bits long.  These cases must be handled specially to avoid
 545      reading extraneous bits from the context.  */
 546   if (is_fiseg_register (r) || is_segment_register (r))
 547     {
 548       gdb_byte bytes[4] = {};
 549       memcpy (bytes, context_offset, 2);
 550       supply_register (regcache, r, bytes);
 551     }
 552   else if (is_fop_register (r))
 553     {
 554       long l = (*((long *) context_offset) >> 16) & ((1 << 11) - 1);
 555       supply_register (regcache, r, (char *) &l);
 556     }
 557   else
 558     supply_register (regcache, r, context_offset);
 559 }
 560
 561 /* Store a new register value into the thread context of TH.  */
 562 static void
 563 i386_store_inferior_register (struct regcache *regcache,
 564                               windows_thread_info *th, int r)
 565 {
 566   const int *mappings;
 567 #ifdef __x86_64__
 568   if (!windows_process.wow64_process)
 569     mappings = amd64_mappings;
 570   else
 571 #endif
 572     mappings = i386_mappings;
 573
 574   char *context_offset;
 575 #ifdef __x86_64__
 576   if (windows_process.wow64_process)
 577     context_offset = (char *) &th->wow64_context + mappings[r];
 578   else
 579 #endif
 580     context_offset = (char *) &th->context + mappings[r];
 581
 582   /* GDB treats some registers as 32-bit, where they are in fact only
 583      16 bits long.  These cases must be handled specially to avoid
 584      overwriting other registers in the context.  */
 585   if (is_fiseg_register (r) || is_segment_register (r))
 586     {
 587       gdb_byte bytes[4];
 588       collect_register (regcache, r, bytes);
 589       memcpy (context_offset, bytes, 2);
 590     }
 591   else if (is_fop_register (r))
 592     {
 593       gdb_byte bytes[4];
 594       collect_register (regcache, r, bytes);
 595       /* The value of FOP occupies the top two bytes in the context,
 596          so write the two low-order bytes from the cache into the
 597          appropriate spot.  */
 598       memcpy (context_offset + 2, bytes, 2);
 599     }
 600   else
 601     collect_register (regcache, r, context_offset);
 602 }
 603
 604 static const unsigned char i386_win32_breakpoint = 0xcc;
 605 #define i386_win32_breakpoint_len 1
 606
 607 static void
 608 i386_arch_setup (void)
 609 {
 610   struct target_desc *tdesc;
 611
 612 #ifdef __x86_64__
 613   tdesc = amd64_create_target_description (X86_XSTATE_SSE_MASK, false,
 614                                            false, false);
 615   init_target_desc (tdesc, amd64_expedite_regs, WINDOWS_OSABI);
 616   win32_tdesc = tdesc;
 617 #endif
 618
 619   tdesc = i386_create_target_description (X86_XSTATE_SSE_MASK, false, false);
 620   init_target_desc (tdesc, i386_expedite_regs, WINDOWS_OSABI);
 621 #ifdef __x86_64__
 622   wow64_win32_tdesc = tdesc;
 623 #else
 624   win32_tdesc = tdesc;
 625 #endif
 626 }
 627
 628 /* Implement win32_target_ops "num_regs" method.  */
 629
 630 static int
 631 i386_win32_num_regs (void)
 632 {
 633   int num_regs;
 634 #ifdef __x86_64__
 635   if (!windows_process.wow64_process)
 636     num_regs = sizeof (amd64_mappings) / sizeof (amd64_mappings[0]);
 637   else
 638 #endif
 639     num_regs = sizeof (i386_mappings) / sizeof (i386_mappings[0]);
 640   return num_regs;
 641 }
 642
 643 /* Implement win32_target_ops "get_pc" method.  */
 644
 645 static CORE_ADDR
 646 i386_win32_get_pc (struct regcache *regcache)
 647 {
 648   bool use_64bit = register_size (regcache->tdesc, 0) == 8;
 649
 650   if (use_64bit)
 651     {
 652       uint64_t pc;
 653
 654       collect_register_by_name (regcache, "rip", &pc);
 655       return (CORE_ADDR) pc;
 656     }
 657   else
 658     {
 659       uint32_t pc;
 660
 661       collect_register_by_name (regcache, "eip", &pc);
 662       return (CORE_ADDR) pc;
 663     }
 664 }
 665
 666 /* Implement win32_target_ops "set_pc" method.  */
 667
 668 static void
 669 i386_win32_set_pc (struct regcache *regcache, CORE_ADDR pc)
 670 {
 671   bool use_64bit = register_size (regcache->tdesc, 0) == 8;
 672
 673   if (use_64bit)
 674     {
 675       uint64_t newpc = pc;
 676
 677       supply_register_by_name (regcache, "rip", &newpc);
 678     }
 679   else
 680     {
 681       uint32_t newpc = pc;
 682
 683       supply_register_by_name (regcache, "eip", &newpc);
 684     }
 685 }
 686
 687 struct win32_target_ops the_low_target = {
 688   i386_arch_setup,
 689   i386_win32_num_regs,
 690   i386_initial_stuff,
 691   i386_get_thread_context,
 692   i386_prepare_to_resume,
 693   i386_thread_added,
 694   i386_fetch_inferior_register,
 695   i386_store_inferior_register,
 696   i386_single_step,
 697   &i386_win32_breakpoint,
 698   i386_win32_breakpoint_len,
 699   1,
 700   i386_win32_get_pc,
 701   i386_win32_set_pc,
 702   i386_supports_z_point_type,
 703   i386_insert_point,
 704   i386_remove_point,
 705   x86_stopped_by_watchpoint,
 706   x86_stopped_data_address
 707 };