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 #define RET_DR(DR)                              \
  84   case DR:                                      \
  85     return th->context.Dr ## DR
  86
  87   switch (dr)
  88     {
  89       RET_DR (0);
  90       RET_DR (1);
  91       RET_DR (2);
  92       RET_DR (3);
  93       RET_DR (6);
  94       RET_DR (7);
  95     }
  96
  97 #undef RET_DR
  98
  99   gdb_assert_not_reached ("unhandled dr");
 100 }
 101
 102 static CORE_ADDR
 103 x86_dr_low_get_addr (int regnum)
 104 {
 105   gdb_assert (DR_FIRSTADDR <= regnum && regnum <= DR_LASTADDR);
 106
 107   return win32_get_current_dr (regnum - DR_FIRSTADDR);
 108 }
 109
 110 static unsigned long
 111 x86_dr_low_get_control (void)
 112 {
 113   return win32_get_current_dr (7);
 114 }
 115
 116 /* Get the value of the DR6 debug status register from the inferior
 117    and record it in STATE.  */
 118
 119 static unsigned long
 120 x86_dr_low_get_status (void)
 121 {
 122   return win32_get_current_dr (6);
 123 }
 124
 125 /* Low-level function vector.  */
 126 struct x86_dr_low_type x86_dr_low =
 127   {
 128     x86_dr_low_set_control,
 129     x86_dr_low_set_addr,
 130     x86_dr_low_get_addr,
 131     x86_dr_low_get_status,
 132     x86_dr_low_get_control,
 133     sizeof (void *),
 134   };
 135
 136 /* Breakpoint/watchpoint support.  */
 137
 138 static int
 139 i386_supports_z_point_type (char z_type)
 140 {
 141   switch (z_type)
 142     {
 143     case Z_PACKET_WRITE_WP:
 144     case Z_PACKET_ACCESS_WP:
 145       return 1;
 146     default:
 147       return 0;
 148     }
 149 }
 150
 151 static int
 152 i386_insert_point (enum raw_bkpt_type type, CORE_ADDR addr,
 153                    int size, struct raw_breakpoint *bp)
 154 {
 155   switch (type)
 156     {
 157     case raw_bkpt_type_write_wp:
 158     case raw_bkpt_type_access_wp:
 159       {
 160         enum target_hw_bp_type hw_type
 161           = raw_bkpt_type_to_target_hw_bp_type (type);
 162
 163         return x86_dr_insert_watchpoint (&debug_reg_state,
 164                                          hw_type, addr, size);
 165       }
 166     default:
 167       /* Unsupported.  */
 168       return 1;
 169     }
 170 }
 171
 172 static int
 173 i386_remove_point (enum raw_bkpt_type type, CORE_ADDR addr,
 174                    int size, struct raw_breakpoint *bp)
 175 {
 176   switch (type)
 177     {
 178     case raw_bkpt_type_write_wp:
 179     case raw_bkpt_type_access_wp:
 180       {
 181         enum target_hw_bp_type hw_type
 182           = raw_bkpt_type_to_target_hw_bp_type (type);
 183
 184         return x86_dr_remove_watchpoint (&debug_reg_state,
 185                                          hw_type, addr, size);
 186       }
 187     default:
 188       /* Unsupported.  */
 189       return 1;
 190     }
 191 }
 192
 193 static int
 194 x86_stopped_by_watchpoint (void)
 195 {
 196   return x86_dr_stopped_by_watchpoint (&debug_reg_state);
 197 }
 198
 199 static CORE_ADDR
 200 x86_stopped_data_address (void)
 201 {
 202   CORE_ADDR addr;
 203   if (x86_dr_stopped_data_address (&debug_reg_state, &addr))
 204     return addr;
 205   return 0;
 206 }
 207
 208 static void
 209 i386_initial_stuff (void)
 210 {
 211   x86_low_init_dregs (&debug_reg_state);
 212 }
 213
 214 static void
 215 i386_get_thread_context (windows_thread_info *th)
 216 {
 217   /* Requesting the CONTEXT_EXTENDED_REGISTERS register set fails if
 218      the system doesn't support extended registers.  */
 219   static DWORD extended_registers = CONTEXT_EXTENDED_REGISTERS;
 220
 221  again:
 222   th->context.ContextFlags = (CONTEXT_FULL
 223                               | CONTEXT_FLOATING_POINT
 224                               | CONTEXT_DEBUG_REGISTERS
 225                               | extended_registers);
 226
 227   if (!GetThreadContext (th->h, &th->context))
 228     {
 229       DWORD e = GetLastError ();
 230
 231       if (extended_registers && e == ERROR_INVALID_PARAMETER)
 232         {
 233           extended_registers = 0;
 234           goto again;
 235         }
 236
 237       error ("GetThreadContext failure %ld\n", (long) e);
 238     }
 239 }
 240
 241 static void
 242 i386_prepare_to_resume (windows_thread_info *th)
 243 {
 244   if (th->debug_registers_changed)
 245     {
 246       struct x86_debug_reg_state *dr = &debug_reg_state;
 247
 248       win32_require_context (th);
 249
 250       th->context.Dr0 = dr->dr_mirror[0];
 251       th->context.Dr1 = dr->dr_mirror[1];
 252       th->context.Dr2 = dr->dr_mirror[2];
 253       th->context.Dr3 = dr->dr_mirror[3];
 254       /* th->context.Dr6 = dr->dr_status_mirror;
 255          FIXME: should we set dr6 also ?? */
 256       th->context.Dr7 = dr->dr_control_mirror;
 257
 258       th->debug_registers_changed = false;
 259     }
 260 }
 261
 262 static void
 263 i386_thread_added (windows_thread_info *th)
 264 {
 265   th->debug_registers_changed = true;
 266 }
 267
 268 static void
 269 i386_single_step (windows_thread_info *th)
 270 {
 271   th->context.EFlags |= FLAG_TRACE_BIT;
 272 }
 273
 274 #ifndef __x86_64__
 275
 276 /* An array of offset mappings into a Win32 Context structure.
 277    This is a one-to-one mapping which is indexed by gdb's register
 278    numbers.  It retrieves an offset into the context structure where
 279    the 4 byte register is located.
 280    An offset value of -1 indicates that Win32 does not provide this
 281    register in it's CONTEXT structure.  In this case regptr will return
 282    a pointer into a dummy register.  */
 283 #define context_offset(x) ((int)&(((CONTEXT *)NULL)->x))
 284 static const int mappings[] = {
 285   context_offset (Eax),
 286   context_offset (Ecx),
 287   context_offset (Edx),
 288   context_offset (Ebx),
 289   context_offset (Esp),
 290   context_offset (Ebp),
 291   context_offset (Esi),
 292   context_offset (Edi),
 293   context_offset (Eip),
 294   context_offset (EFlags),
 295   context_offset (SegCs),
 296   context_offset (SegSs),
 297   context_offset (SegDs),
 298   context_offset (SegEs),
 299   context_offset (SegFs),
 300   context_offset (SegGs),
 301   context_offset (FloatSave.RegisterArea[0 * 10]),
 302   context_offset (FloatSave.RegisterArea[1 * 10]),
 303   context_offset (FloatSave.RegisterArea[2 * 10]),
 304   context_offset (FloatSave.RegisterArea[3 * 10]),
 305   context_offset (FloatSave.RegisterArea[4 * 10]),
 306   context_offset (FloatSave.RegisterArea[5 * 10]),
 307   context_offset (FloatSave.RegisterArea[6 * 10]),
 308   context_offset (FloatSave.RegisterArea[7 * 10]),
 309   context_offset (FloatSave.ControlWord),
 310   context_offset (FloatSave.StatusWord),
 311   context_offset (FloatSave.TagWord),
 312   context_offset (FloatSave.ErrorSelector),
 313   context_offset (FloatSave.ErrorOffset),
 314   context_offset (FloatSave.DataSelector),
 315   context_offset (FloatSave.DataOffset),
 316   context_offset (FloatSave.ErrorSelector),
 317   /* XMM0-7 */
 318   context_offset (ExtendedRegisters[10 * 16]),
 319   context_offset (ExtendedRegisters[11 * 16]),
 320   context_offset (ExtendedRegisters[12 * 16]),
 321   context_offset (ExtendedRegisters[13 * 16]),
 322   context_offset (ExtendedRegisters[14 * 16]),
 323   context_offset (ExtendedRegisters[15 * 16]),
 324   context_offset (ExtendedRegisters[16 * 16]),
 325   context_offset (ExtendedRegisters[17 * 16]),
 326   /* MXCSR */
 327   context_offset (ExtendedRegisters[24])
 328 };
 329 #undef context_offset
 330
 331 #else /* __x86_64__ */
 332
 333 #define context_offset(x) (offsetof (CONTEXT, x))
 334 static const int mappings[] =
 335 {
 336   context_offset (Rax),
 337   context_offset (Rbx),
 338   context_offset (Rcx),
 339   context_offset (Rdx),
 340   context_offset (Rsi),
 341   context_offset (Rdi),
 342   context_offset (Rbp),
 343   context_offset (Rsp),
 344   context_offset (R8),
 345   context_offset (R9),
 346   context_offset (R10),
 347   context_offset (R11),
 348   context_offset (R12),
 349   context_offset (R13),
 350   context_offset (R14),
 351   context_offset (R15),
 352   context_offset (Rip),
 353   context_offset (EFlags),
 354   context_offset (SegCs),
 355   context_offset (SegSs),
 356   context_offset (SegDs),
 357   context_offset (SegEs),
 358   context_offset (SegFs),
 359   context_offset (SegGs),
 360   context_offset (FloatSave.FloatRegisters[0]),
 361   context_offset (FloatSave.FloatRegisters[1]),
 362   context_offset (FloatSave.FloatRegisters[2]),
 363   context_offset (FloatSave.FloatRegisters[3]),
 364   context_offset (FloatSave.FloatRegisters[4]),
 365   context_offset (FloatSave.FloatRegisters[5]),
 366   context_offset (FloatSave.FloatRegisters[6]),
 367   context_offset (FloatSave.FloatRegisters[7]),
 368   context_offset (FloatSave.ControlWord),
 369   context_offset (FloatSave.StatusWord),
 370   context_offset (FloatSave.TagWord),
 371   context_offset (FloatSave.ErrorSelector),
 372   context_offset (FloatSave.ErrorOffset),
 373   context_offset (FloatSave.DataSelector),
 374   context_offset (FloatSave.DataOffset),
 375   context_offset (FloatSave.ErrorSelector)
 376   /* XMM0-7 */ ,
 377   context_offset (Xmm0),
 378   context_offset (Xmm1),
 379   context_offset (Xmm2),
 380   context_offset (Xmm3),
 381   context_offset (Xmm4),
 382   context_offset (Xmm5),
 383   context_offset (Xmm6),
 384   context_offset (Xmm7),
 385   context_offset (Xmm8),
 386   context_offset (Xmm9),
 387   context_offset (Xmm10),
 388   context_offset (Xmm11),
 389   context_offset (Xmm12),
 390   context_offset (Xmm13),
 391   context_offset (Xmm14),
 392   context_offset (Xmm15),
 393   /* MXCSR */
 394   context_offset (FloatSave.MxCsr)
 395 };
 396 #undef context_offset
 397
 398 #endif /* __x86_64__ */
 399
 400 /* Fetch register from gdbserver regcache data.  */
 401 static void
 402 i386_fetch_inferior_register (struct regcache *regcache,
 403                               windows_thread_info *th, int r)
 404 {
 405   char *context_offset = (char *) &th->context + mappings[r];
 406
 407   long l;
 408   if (r == FCS_REGNUM)
 409     {
 410       l = *((long *) context_offset) & 0xffff;
 411       supply_register (regcache, r, (char *) &l);
 412     }
 413   else if (r == FOP_REGNUM)
 414     {
 415       l = (*((long *) context_offset) >> 16) & ((1 << 11) - 1);
 416       supply_register (regcache, r, (char *) &l);
 417     }
 418   else
 419     supply_register (regcache, r, context_offset);
 420 }
 421
 422 /* Store a new register value into the thread context of TH.  */
 423 static void
 424 i386_store_inferior_register (struct regcache *regcache,
 425                               windows_thread_info *th, int r)
 426 {
 427   char *context_offset = (char *) &th->context + mappings[r];
 428   collect_register (regcache, r, context_offset);
 429 }
 430
 431 static const unsigned char i386_win32_breakpoint = 0xcc;
 432 #define i386_win32_breakpoint_len 1
 433
 434 static void
 435 i386_arch_setup (void)
 436 {
 437   struct target_desc *tdesc;
 438
 439 #ifdef __x86_64__
 440   tdesc = amd64_create_target_description (X86_XSTATE_SSE_MASK, false,
 441                                            false, false);
 442   const char **expedite_regs = amd64_expedite_regs;
 443 #else
 444   tdesc = i386_create_target_description (X86_XSTATE_SSE_MASK, false, false);
 445   const char **expedite_regs = i386_expedite_regs;
 446 #endif
 447
 448   init_target_desc (tdesc, expedite_regs);
 449
 450   win32_tdesc = tdesc;
 451 }
 452
 453 struct win32_target_ops the_low_target = {
 454   i386_arch_setup,
 455   sizeof (mappings) / sizeof (mappings[0]),
 456   i386_initial_stuff,
 457   i386_get_thread_context,
 458   i386_prepare_to_resume,
 459   i386_thread_added,
 460   i386_fetch_inferior_register,
 461   i386_store_inferior_register,
 462   i386_single_step,
 463   &i386_win32_breakpoint,
 464   i386_win32_breakpoint_len,
 465   i386_supports_z_point_type,
 466   i386_insert_point,
 467   i386_remove_point,
 468   x86_stopped_by_watchpoint,
 469   x86_stopped_data_address
 470 };