gdbserver/win32-i386-low.cc

   1 /* Copyright (C) 2007-2020 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 "server.h"
  19 #include "win32-low.h"
  20 #include "x86-low.h"
  21 #include "gdbsupport/x86-xstate.h"
  22 #ifdef __x86_64__
  23 #include "arch/amd64.h"
  24 #endif
  25 #include "arch/i386.h"
  26 #include "tdesc.h"
  27 #include "x86-tdesc.h"
  28
  29 using namespace windows_nat;
  30
  31 #ifndef CONTEXT_EXTENDED_REGISTERS
  32 #define CONTEXT_EXTENDED_REGISTERS 0
  33 #endif
  34
  35 #define FCS_REGNUM 27
  36 #define FOP_REGNUM 31
  37
  38 #define FLAG_TRACE_BIT 0x100
  39
  40 static struct x86_debug_reg_state debug_reg_state;
  41
  42 static void
  43 update_debug_registers (thread_info *thread)
  44 {
  45   windows_thread_info *th = (windows_thread_info *) thread_target_data (thread);
  46
  47   /* The actual update is done later just before resuming the lwp,
  48      we just mark that the registers need updating.  */
  49   th->debug_registers_changed = true;
  50 }
  51
  52 /* Update the inferior's debug register REGNUM from STATE.  */
  53
  54 static void
  55 x86_dr_low_set_addr (int regnum, CORE_ADDR addr)
  56 {
  57   gdb_assert (DR_FIRSTADDR <= regnum && regnum <= DR_LASTADDR);
  58
  59   /* Only update the threads of this process.  */
  60   for_each_thread (current_thread->id.pid (), update_debug_registers);
  61 }
  62
  63 /* Update the inferior's DR7 debug control register from STATE.  */
  64
  65 static void
  66 x86_dr_low_set_control (unsigned long control)
  67 {
  68   /* Only update the threads of this process.  */
  69   for_each_thread (current_thread->id.pid (), update_debug_registers);
  70 }
  71
  72 /* Return the current value of a DR register of the current thread's
  73    context.  */
  74
  75 static DWORD64
  76 win32_get_current_dr (int dr)
  77 {
  78   windows_thread_info *th
  79     = (windows_thread_info *) thread_target_data (current_thread);
  80
  81   win32_require_context (th);
  82
  83 #ifdef __x86_64__
  84 #define RET_DR(DR)                              \
  85   case DR:                                      \
  86     return th->wow64_context.Dr ## DR
  87
  88   if (wow64_process)
  89     {
  90       switch (dr)
  91         {
  92           RET_DR (0);
  93           RET_DR (1);
  94           RET_DR (2);
  95           RET_DR (3);
  96           RET_DR (6);
  97           RET_DR (7);
  98         }
  99     }
 100   else
 101 #undef RET_DR
 102 #endif
 103 #define RET_DR(DR)                              \
 104   case DR:                                      \
 105     return th->context.Dr ## DR
 106
 107     {
 108       switch (dr)
 109         {
 110           RET_DR (0);
 111           RET_DR (1);
 112           RET_DR (2);
 113           RET_DR (3);
 114           RET_DR (6);
 115           RET_DR (7);
 116         }
 117     }
 118
 119 #undef RET_DR
 120
 121   gdb_assert_not_reached ("unhandled dr");
 122 }
 123
 124 static CORE_ADDR
 125 x86_dr_low_get_addr (int regnum)
 126 {
 127   gdb_assert (DR_FIRSTADDR <= regnum && regnum <= DR_LASTADDR);
 128
 129   return win32_get_current_dr (regnum - DR_FIRSTADDR);
 130 }
 131
 132 static unsigned long
 133 x86_dr_low_get_control (void)
 134 {
 135   return win32_get_current_dr (7);
 136 }
 137
 138 /* Get the value of the DR6 debug status register from the inferior
 139    and record it in STATE.  */
 140
 141 static unsigned long
 142 x86_dr_low_get_status (void)
 143 {
 144   return win32_get_current_dr (6);
 145 }
 146
 147 /* Low-level function vector.  */
 148 struct x86_dr_low_type x86_dr_low =
 149   {
 150     x86_dr_low_set_control,
 151     x86_dr_low_set_addr,
 152     x86_dr_low_get_addr,
 153     x86_dr_low_get_status,
 154     x86_dr_low_get_control,
 155     sizeof (void *),
 156   };
 157
 158 /* Breakpoint/watchpoint support.  */
 159
 160 static int
 161 i386_supports_z_point_type (char z_type)
 162 {
 163   switch (z_type)
 164     {
 165     case Z_PACKET_HW_BP:
 166     case Z_PACKET_WRITE_WP:
 167     case Z_PACKET_ACCESS_WP:
 168       return 1;
 169     default:
 170       return 0;
 171     }
 172 }
 173
 174 static int
 175 i386_insert_point (enum raw_bkpt_type type, CORE_ADDR addr,
 176                    int size, struct raw_breakpoint *bp)
 177 {
 178   switch (type)
 179     {
 180     case raw_bkpt_type_hw:
 181     case raw_bkpt_type_write_wp:
 182     case raw_bkpt_type_access_wp:
 183       {
 184         enum target_hw_bp_type hw_type
 185           = raw_bkpt_type_to_target_hw_bp_type (type);
 186
 187         return x86_dr_insert_watchpoint (&debug_reg_state,
 188                                          hw_type, addr, size);
 189       }
 190     default:
 191       /* Unsupported.  */
 192       return 1;
 193     }
 194 }
 195
 196 static int
 197 i386_remove_point (enum raw_bkpt_type type, CORE_ADDR addr,
 198                    int size, struct raw_breakpoint *bp)
 199 {
 200   switch (type)
 201     {
 202     case raw_bkpt_type_hw:
 203     case raw_bkpt_type_write_wp:
 204     case raw_bkpt_type_access_wp:
 205       {
 206         enum target_hw_bp_type hw_type
 207           = raw_bkpt_type_to_target_hw_bp_type (type);
 208
 209         return x86_dr_remove_watchpoint (&debug_reg_state,
 210                                          hw_type, addr, size);
 211       }
 212     default:
 213       /* Unsupported.  */
 214       return 1;
 215     }
 216 }
 217
 218 static int
 219 x86_stopped_by_watchpoint (void)
 220 {
 221   return x86_dr_stopped_by_watchpoint (&debug_reg_state);
 222 }
 223
 224 static CORE_ADDR
 225 x86_stopped_data_address (void)
 226 {
 227   CORE_ADDR addr;
 228   if (x86_dr_stopped_data_address (&debug_reg_state, &addr))
 229     return addr;
 230   return 0;
 231 }
 232
 233 static void
 234 i386_initial_stuff (void)
 235 {
 236   x86_low_init_dregs (&debug_reg_state);
 237 }
 238
 239 static void
 240 i386_get_thread_context (windows_thread_info *th)
 241 {
 242   /* Requesting the CONTEXT_EXTENDED_REGISTERS register set fails if
 243      the system doesn't support extended registers.  */
 244   static DWORD extended_registers = CONTEXT_EXTENDED_REGISTERS;
 245
 246  again:
 247 #ifdef __x86_64__
 248   if (wow64_process)
 249     th->wow64_context.ContextFlags = (CONTEXT_FULL
 250                                       | CONTEXT_FLOATING_POINT
 251                                       | CONTEXT_DEBUG_REGISTERS
 252                                       | extended_registers);
 253   else
 254 #endif
 255     th->context.ContextFlags = (CONTEXT_FULL
 256                                 | CONTEXT_FLOATING_POINT
 257                                 | CONTEXT_DEBUG_REGISTERS
 258                                 | extended_registers);
 259
 260   BOOL ret;
 261 #ifdef __x86_64__
 262   if (wow64_process)
 263     ret = win32_Wow64GetThreadContext (th->h, &th->wow64_context);
 264   else
 265 #endif
 266     ret = GetThreadContext (th->h, &th->context);
 267   if (!ret)
 268     {
 269       DWORD e = GetLastError ();
 270
 271       if (extended_registers && e == ERROR_INVALID_PARAMETER)
 272         {
 273           extended_registers = 0;
 274           goto again;
 275         }
 276
 277       error ("GetThreadContext failure %ld\n", (long) e);
 278     }
 279 }
 280
 281 static void
 282 i386_prepare_to_resume (windows_thread_info *th)
 283 {
 284   if (th->debug_registers_changed)
 285     {
 286       struct x86_debug_reg_state *dr = &debug_reg_state;
 287
 288       win32_require_context (th);
 289
 290 #ifdef __x86_64__
 291       if (wow64_process)
 292         {
 293           th->wow64_context.Dr0 = dr->dr_mirror[0];
 294           th->wow64_context.Dr1 = dr->dr_mirror[1];
 295           th->wow64_context.Dr2 = dr->dr_mirror[2];
 296           th->wow64_context.Dr3 = dr->dr_mirror[3];
 297           /* th->wow64_context.Dr6 = dr->dr_status_mirror;
 298              FIXME: should we set dr6 also ?? */
 299           th->wow64_context.Dr7 = dr->dr_control_mirror;
 300         }
 301       else
 302 #endif
 303         {
 304           th->context.Dr0 = dr->dr_mirror[0];
 305           th->context.Dr1 = dr->dr_mirror[1];
 306           th->context.Dr2 = dr->dr_mirror[2];
 307           th->context.Dr3 = dr->dr_mirror[3];
 308           /* th->context.Dr6 = dr->dr_status_mirror;
 309              FIXME: should we set dr6 also ?? */
 310           th->context.Dr7 = dr->dr_control_mirror;
 311         }
 312
 313       th->debug_registers_changed = false;
 314     }
 315 }
 316
 317 static void
 318 i386_thread_added (windows_thread_info *th)
 319 {
 320   th->debug_registers_changed = true;
 321 }
 322
 323 static void
 324 i386_single_step (windows_thread_info *th)
 325 {
 326 #ifdef __x86_64__
 327   if (wow64_process)
 328     th->wow64_context.EFlags |= FLAG_TRACE_BIT;
 329   else
 330 #endif
 331     th->context.EFlags |= FLAG_TRACE_BIT;
 332 }
 333
 334 /* An array of offset mappings into a Win32 Context structure.
 335    This is a one-to-one mapping which is indexed by gdb's register
 336    numbers.  It retrieves an offset into the context structure where
 337    the 4 byte register is located.
 338    An offset value of -1 indicates that Win32 does not provide this
 339    register in it's CONTEXT structure.  In this case regptr will return
 340    a pointer into a dummy register.  */
 341 #ifdef __x86_64__
 342 #define context_offset(x) (offsetof (WOW64_CONTEXT, x))
 343 #else
 344 #define context_offset(x) ((int)&(((CONTEXT *)NULL)->x))
 345 #endif
 346 static const int i386_mappings[] = {
 347   context_offset (Eax),
 348   context_offset (Ecx),
 349   context_offset (Edx),
 350   context_offset (Ebx),
 351   context_offset (Esp),
 352   context_offset (Ebp),
 353   context_offset (Esi),
 354   context_offset (Edi),
 355   context_offset (Eip),
 356   context_offset (EFlags),
 357   context_offset (SegCs),
 358   context_offset (SegSs),
 359   context_offset (SegDs),
 360   context_offset (SegEs),
 361   context_offset (SegFs),
 362   context_offset (SegGs),
 363   context_offset (FloatSave.RegisterArea[0 * 10]),
 364   context_offset (FloatSave.RegisterArea[1 * 10]),
 365   context_offset (FloatSave.RegisterArea[2 * 10]),
 366   context_offset (FloatSave.RegisterArea[3 * 10]),
 367   context_offset (FloatSave.RegisterArea[4 * 10]),
 368   context_offset (FloatSave.RegisterArea[5 * 10]),
 369   context_offset (FloatSave.RegisterArea[6 * 10]),
 370   context_offset (FloatSave.RegisterArea[7 * 10]),
 371   context_offset (FloatSave.ControlWord),
 372   context_offset (FloatSave.StatusWord),
 373   context_offset (FloatSave.TagWord),
 374   context_offset (FloatSave.ErrorSelector),
 375   context_offset (FloatSave.ErrorOffset),
 376   context_offset (FloatSave.DataSelector),
 377   context_offset (FloatSave.DataOffset),
 378   context_offset (FloatSave.ErrorSelector),
 379   /* XMM0-7 */
 380   context_offset (ExtendedRegisters[10 * 16]),
 381   context_offset (ExtendedRegisters[11 * 16]),
 382   context_offset (ExtendedRegisters[12 * 16]),
 383   context_offset (ExtendedRegisters[13 * 16]),
 384   context_offset (ExtendedRegisters[14 * 16]),
 385   context_offset (ExtendedRegisters[15 * 16]),
 386   context_offset (ExtendedRegisters[16 * 16]),
 387   context_offset (ExtendedRegisters[17 * 16]),
 388   /* MXCSR */
 389   context_offset (ExtendedRegisters[24])
 390 };
 391 #undef context_offset
 392
 393 #ifdef __x86_64__
 394
 395 #define context_offset(x) (offsetof (CONTEXT, x))
 396 static const int amd64_mappings[] =
 397 {
 398   context_offset (Rax),
 399   context_offset (Rbx),
 400   context_offset (Rcx),
 401   context_offset (Rdx),
 402   context_offset (Rsi),
 403   context_offset (Rdi),
 404   context_offset (Rbp),
 405   context_offset (Rsp),
 406   context_offset (R8),
 407   context_offset (R9),
 408   context_offset (R10),
 409   context_offset (R11),
 410   context_offset (R12),
 411   context_offset (R13),
 412   context_offset (R14),
 413   context_offset (R15),
 414   context_offset (Rip),
 415   context_offset (EFlags),
 416   context_offset (SegCs),
 417   context_offset (SegSs),
 418   context_offset (SegDs),
 419   context_offset (SegEs),
 420   context_offset (SegFs),
 421   context_offset (SegGs),
 422   context_offset (FloatSave.FloatRegisters[0]),
 423   context_offset (FloatSave.FloatRegisters[1]),
 424   context_offset (FloatSave.FloatRegisters[2]),
 425   context_offset (FloatSave.FloatRegisters[3]),
 426   context_offset (FloatSave.FloatRegisters[4]),
 427   context_offset (FloatSave.FloatRegisters[5]),
 428   context_offset (FloatSave.FloatRegisters[6]),
 429   context_offset (FloatSave.FloatRegisters[7]),
 430   context_offset (FloatSave.ControlWord),
 431   context_offset (FloatSave.StatusWord),
 432   context_offset (FloatSave.TagWord),
 433   context_offset (FloatSave.ErrorSelector),
 434   context_offset (FloatSave.ErrorOffset),
 435   context_offset (FloatSave.DataSelector),
 436   context_offset (FloatSave.DataOffset),
 437   context_offset (FloatSave.ErrorSelector)
 438   /* XMM0-7 */ ,
 439   context_offset (Xmm0),
 440   context_offset (Xmm1),
 441   context_offset (Xmm2),
 442   context_offset (Xmm3),
 443   context_offset (Xmm4),
 444   context_offset (Xmm5),
 445   context_offset (Xmm6),
 446   context_offset (Xmm7),
 447   context_offset (Xmm8),
 448   context_offset (Xmm9),
 449   context_offset (Xmm10),
 450   context_offset (Xmm11),
 451   context_offset (Xmm12),
 452   context_offset (Xmm13),
 453   context_offset (Xmm14),
 454   context_offset (Xmm15),
 455   /* MXCSR */
 456   context_offset (FloatSave.MxCsr)
 457 };
 458 #undef context_offset
 459
 460 #endif /* __x86_64__ */
 461
 462 /* Fetch register from gdbserver regcache data.  */
 463 static void
 464 i386_fetch_inferior_register (struct regcache *regcache,
 465                               windows_thread_info *th, int r)
 466 {
 467   const int *mappings;
 468 #ifdef __x86_64__
 469   if (!wow64_process)
 470     mappings = amd64_mappings;
 471   else
 472 #endif
 473     mappings = i386_mappings;
 474
 475   char *context_offset;
 476 #ifdef __x86_64__
 477   if (wow64_process)
 478     context_offset = (char *) &th->wow64_context + mappings[r];
 479   else
 480 #endif
 481     context_offset = (char *) &th->context + mappings[r];
 482
 483   long l;
 484   if (r == FCS_REGNUM)
 485     {
 486       l = *((long *) context_offset) & 0xffff;
 487       supply_register (regcache, r, (char *) &l);
 488     }
 489   else if (r == FOP_REGNUM)
 490     {
 491       l = (*((long *) context_offset) >> 16) & ((1 << 11) - 1);
 492       supply_register (regcache, r, (char *) &l);
 493     }
 494   else
 495     supply_register (regcache, r, context_offset);
 496 }
 497
 498 /* Store a new register value into the thread context of TH.  */
 499 static void
 500 i386_store_inferior_register (struct regcache *regcache,
 501                               windows_thread_info *th, int r)
 502 {
 503   const int *mappings;
 504 #ifdef __x86_64__
 505   if (!wow64_process)
 506     mappings = amd64_mappings;
 507   else
 508 #endif
 509     mappings = i386_mappings;
 510
 511   char *context_offset;
 512 #ifdef __x86_64__
 513   if (wow64_process)
 514     context_offset = (char *) &th->wow64_context + mappings[r];
 515   else
 516 #endif
 517     context_offset = (char *) &th->context + mappings[r];
 518
 519   collect_register (regcache, r, context_offset);
 520 }
 521
 522 static const unsigned char i386_win32_breakpoint = 0xcc;
 523 #define i386_win32_breakpoint_len 1
 524
 525 static void
 526 i386_arch_setup (void)
 527 {
 528   struct target_desc *tdesc;
 529
 530 #ifdef __x86_64__
 531   tdesc = amd64_create_target_description (X86_XSTATE_SSE_MASK, false,
 532                                            false, false);
 533   init_target_desc (tdesc, amd64_expedite_regs);
 534   win32_tdesc = tdesc;
 535 #endif
 536
 537   tdesc = i386_create_target_description (X86_XSTATE_SSE_MASK, false, false);
 538   init_target_desc (tdesc, i386_expedite_regs);
 539 #ifdef __x86_64__
 540   wow64_win32_tdesc = tdesc;
 541 #else
 542   win32_tdesc = tdesc;
 543 #endif
 544 }
 545
 546 /* Implement win32_target_ops "num_regs" method.  */
 547
 548 static int
 549 i386_win32_num_regs (void)
 550 {
 551   int num_regs;
 552 #ifdef __x86_64__
 553   if (!wow64_process)
 554     num_regs = sizeof (amd64_mappings) / sizeof (amd64_mappings[0]);
 555   else
 556 #endif
 557     num_regs = sizeof (i386_mappings) / sizeof (i386_mappings[0]);
 558   return num_regs;
 559 }
 560
 561 /* Implement win32_target_ops "get_pc" method.  */
 562
 563 static CORE_ADDR
 564 i386_win32_get_pc (struct regcache *regcache)
 565 {
 566   bool use_64bit = register_size (regcache->tdesc, 0) == 8;
 567
 568   if (use_64bit)
 569     {
 570       uint64_t pc;
 571
 572       collect_register_by_name (regcache, "rip", &pc);
 573       return (CORE_ADDR) pc;
 574     }
 575   else
 576     {
 577       uint32_t pc;
 578
 579       collect_register_by_name (regcache, "eip", &pc);
 580       return (CORE_ADDR) pc;
 581     }
 582 }
 583
 584 /* Implement win32_target_ops "set_pc" method.  */
 585
 586 static void
 587 i386_win32_set_pc (struct regcache *regcache, CORE_ADDR pc)
 588 {
 589   bool use_64bit = register_size (regcache->tdesc, 0) == 8;
 590
 591   if (use_64bit)
 592     {
 593       uint64_t newpc = pc;
 594
 595       supply_register_by_name (regcache, "rip", &newpc);
 596     }
 597   else
 598     {
 599       uint32_t newpc = pc;
 600
 601       supply_register_by_name (regcache, "eip", &newpc);
 602     }
 603 }
 604
 605 struct win32_target_ops the_low_target = {
 606   i386_arch_setup,
 607   i386_win32_num_regs,
 608   i386_initial_stuff,
 609   i386_get_thread_context,
 610   i386_prepare_to_resume,
 611   i386_thread_added,
 612   i386_fetch_inferior_register,
 613   i386_store_inferior_register,
 614   i386_single_step,
 615   &i386_win32_breakpoint,
 616   i386_win32_breakpoint_len,
 617   1,
 618   i386_win32_get_pc,
 619   i386_win32_set_pc,
 620   i386_supports_z_point_type,
 621   i386_insert_point,
 622   i386_remove_point,
 623   x86_stopped_by_watchpoint,
 624   x86_stopped_data_address
 625 };