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 #ifndef CONTEXT_EXTENDED_REGISTERS
  30 #define CONTEXT_EXTENDED_REGISTERS 0
  31 #endif
  32
  33 #define FCS_REGNUM 27
  34 #define FOP_REGNUM 31
  35
  36 #define FLAG_TRACE_BIT 0x100
  37
  38 static struct x86_debug_reg_state debug_reg_state;
  39
  40 static void
  41 update_debug_registers (thread_info *thread)
  42 {
  43   win32_thread_info *th = (win32_thread_info *) thread_target_data (thread);
  44
  45   /* The actual update is done later just before resuming the lwp,
  46      we just mark that the registers need updating.  */
  47   th->debug_registers_changed = 1;
  48 }
  49
  50 /* Update the inferior's debug register REGNUM from STATE.  */
  51
  52 static void
  53 x86_dr_low_set_addr (int regnum, CORE_ADDR addr)
  54 {
  55   gdb_assert (DR_FIRSTADDR <= regnum && regnum <= DR_LASTADDR);
  56
  57   /* Only update the threads of this process.  */
  58   for_each_thread (current_thread->id.pid (), update_debug_registers);
  59 }
  60
  61 /* Update the inferior's DR7 debug control register from STATE.  */
  62
  63 static void
  64 x86_dr_low_set_control (unsigned long control)
  65 {
  66   /* Only update the threads of this process.  */
  67   for_each_thread (current_thread->id.pid (), update_debug_registers);
  68 }
  69
  70 /* Return the current value of a DR register of the current thread's
  71    context.  */
  72
  73 static DWORD64
  74 win32_get_current_dr (int dr)
  75 {
  76   win32_thread_info *th
  77     = (win32_thread_info *) thread_target_data (current_thread);
  78
  79   win32_require_context (th);
  80
  81 #define RET_DR(DR)                              \
  82   case DR:                                      \
  83     return th->context.Dr ## DR
  84
  85   switch (dr)
  86     {
  87       RET_DR (0);
  88       RET_DR (1);
  89       RET_DR (2);
  90       RET_DR (3);
  91       RET_DR (6);
  92       RET_DR (7);
  93     }
  94
  95 #undef RET_DR
  96
  97   gdb_assert_not_reached ("unhandled dr");
  98 }
  99
 100 static CORE_ADDR
 101 x86_dr_low_get_addr (int regnum)
 102 {
 103   gdb_assert (DR_FIRSTADDR <= regnum && regnum <= DR_LASTADDR);
 104
 105   return win32_get_current_dr (regnum - DR_FIRSTADDR);
 106 }
 107
 108 static unsigned long
 109 x86_dr_low_get_control (void)
 110 {
 111   return win32_get_current_dr (7);
 112 }
 113
 114 /* Get the value of the DR6 debug status register from the inferior
 115    and record it in STATE.  */
 116
 117 static unsigned long
 118 x86_dr_low_get_status (void)
 119 {
 120   return win32_get_current_dr (6);
 121 }
 122
 123 /* Low-level function vector.  */
 124 struct x86_dr_low_type x86_dr_low =
 125   {
 126     x86_dr_low_set_control,
 127     x86_dr_low_set_addr,
 128     x86_dr_low_get_addr,
 129     x86_dr_low_get_status,
 130     x86_dr_low_get_control,
 131     sizeof (void *),
 132   };
 133
 134 /* Breakpoint/watchpoint support.  */
 135
 136 static int
 137 i386_supports_z_point_type (char z_type)
 138 {
 139   switch (z_type)
 140     {
 141     case Z_PACKET_WRITE_WP:
 142     case Z_PACKET_ACCESS_WP:
 143       return 1;
 144     default:
 145       return 0;
 146     }
 147 }
 148
 149 static int
 150 i386_insert_point (enum raw_bkpt_type type, CORE_ADDR addr,
 151                    int size, struct raw_breakpoint *bp)
 152 {
 153   switch (type)
 154     {
 155     case raw_bkpt_type_write_wp:
 156     case raw_bkpt_type_access_wp:
 157       {
 158         enum target_hw_bp_type hw_type
 159           = raw_bkpt_type_to_target_hw_bp_type (type);
 160
 161         return x86_dr_insert_watchpoint (&debug_reg_state,
 162                                          hw_type, addr, size);
 163       }
 164     default:
 165       /* Unsupported.  */
 166       return 1;
 167     }
 168 }
 169
 170 static int
 171 i386_remove_point (enum raw_bkpt_type type, CORE_ADDR addr,
 172                    int size, struct raw_breakpoint *bp)
 173 {
 174   switch (type)
 175     {
 176     case raw_bkpt_type_write_wp:
 177     case raw_bkpt_type_access_wp:
 178       {
 179         enum target_hw_bp_type hw_type
 180           = raw_bkpt_type_to_target_hw_bp_type (type);
 181
 182         return x86_dr_remove_watchpoint (&debug_reg_state,
 183                                          hw_type, addr, size);
 184       }
 185     default:
 186       /* Unsupported.  */
 187       return 1;
 188     }
 189 }
 190
 191 static int
 192 x86_stopped_by_watchpoint (void)
 193 {
 194   return x86_dr_stopped_by_watchpoint (&debug_reg_state);
 195 }
 196
 197 static CORE_ADDR
 198 x86_stopped_data_address (void)
 199 {
 200   CORE_ADDR addr;
 201   if (x86_dr_stopped_data_address (&debug_reg_state, &addr))
 202     return addr;
 203   return 0;
 204 }
 205
 206 static void
 207 i386_initial_stuff (void)
 208 {
 209   x86_low_init_dregs (&debug_reg_state);
 210 }
 211
 212 static void
 213 i386_get_thread_context (win32_thread_info *th)
 214 {
 215   /* Requesting the CONTEXT_EXTENDED_REGISTERS register set fails if
 216      the system doesn't support extended registers.  */
 217   static DWORD extended_registers = CONTEXT_EXTENDED_REGISTERS;
 218
 219  again:
 220   th->context.ContextFlags = (CONTEXT_FULL
 221                               | CONTEXT_FLOATING_POINT
 222                               | CONTEXT_DEBUG_REGISTERS
 223                               | extended_registers);
 224
 225   if (!GetThreadContext (th->h, &th->context))
 226     {
 227       DWORD e = GetLastError ();
 228
 229       if (extended_registers && e == ERROR_INVALID_PARAMETER)
 230         {
 231           extended_registers = 0;
 232           goto again;
 233         }
 234
 235       error ("GetThreadContext failure %ld\n", (long) e);
 236     }
 237 }
 238
 239 static void
 240 i386_prepare_to_resume (win32_thread_info *th)
 241 {
 242   if (th->debug_registers_changed)
 243     {
 244       struct x86_debug_reg_state *dr = &debug_reg_state;
 245
 246       win32_require_context (th);
 247
 248       th->context.Dr0 = dr->dr_mirror[0];
 249       th->context.Dr1 = dr->dr_mirror[1];
 250       th->context.Dr2 = dr->dr_mirror[2];
 251       th->context.Dr3 = dr->dr_mirror[3];
 252       /* th->context.Dr6 = dr->dr_status_mirror;
 253          FIXME: should we set dr6 also ?? */
 254       th->context.Dr7 = dr->dr_control_mirror;
 255
 256       th->debug_registers_changed = 0;
 257     }
 258 }
 259
 260 static void
 261 i386_thread_added (win32_thread_info *th)
 262 {
 263   th->debug_registers_changed = 1;
 264 }
 265
 266 static void
 267 i386_single_step (win32_thread_info *th)
 268 {
 269   th->context.EFlags |= FLAG_TRACE_BIT;
 270 }
 271
 272 #ifndef __x86_64__
 273
 274 /* An array of offset mappings into a Win32 Context structure.
 275    This is a one-to-one mapping which is indexed by gdb's register
 276    numbers.  It retrieves an offset into the context structure where
 277    the 4 byte register is located.
 278    An offset value of -1 indicates that Win32 does not provide this
 279    register in it's CONTEXT structure.  In this case regptr will return
 280    a pointer into a dummy register.  */
 281 #define context_offset(x) ((int)&(((CONTEXT *)NULL)->x))
 282 static const int mappings[] = {
 283   context_offset (Eax),
 284   context_offset (Ecx),
 285   context_offset (Edx),
 286   context_offset (Ebx),
 287   context_offset (Esp),
 288   context_offset (Ebp),
 289   context_offset (Esi),
 290   context_offset (Edi),
 291   context_offset (Eip),
 292   context_offset (EFlags),
 293   context_offset (SegCs),
 294   context_offset (SegSs),
 295   context_offset (SegDs),
 296   context_offset (SegEs),
 297   context_offset (SegFs),
 298   context_offset (SegGs),
 299   context_offset (FloatSave.RegisterArea[0 * 10]),
 300   context_offset (FloatSave.RegisterArea[1 * 10]),
 301   context_offset (FloatSave.RegisterArea[2 * 10]),
 302   context_offset (FloatSave.RegisterArea[3 * 10]),
 303   context_offset (FloatSave.RegisterArea[4 * 10]),
 304   context_offset (FloatSave.RegisterArea[5 * 10]),
 305   context_offset (FloatSave.RegisterArea[6 * 10]),
 306   context_offset (FloatSave.RegisterArea[7 * 10]),
 307   context_offset (FloatSave.ControlWord),
 308   context_offset (FloatSave.StatusWord),
 309   context_offset (FloatSave.TagWord),
 310   context_offset (FloatSave.ErrorSelector),
 311   context_offset (FloatSave.ErrorOffset),
 312   context_offset (FloatSave.DataSelector),
 313   context_offset (FloatSave.DataOffset),
 314   context_offset (FloatSave.ErrorSelector),
 315   /* XMM0-7 */
 316   context_offset (ExtendedRegisters[10 * 16]),
 317   context_offset (ExtendedRegisters[11 * 16]),
 318   context_offset (ExtendedRegisters[12 * 16]),
 319   context_offset (ExtendedRegisters[13 * 16]),
 320   context_offset (ExtendedRegisters[14 * 16]),
 321   context_offset (ExtendedRegisters[15 * 16]),
 322   context_offset (ExtendedRegisters[16 * 16]),
 323   context_offset (ExtendedRegisters[17 * 16]),
 324   /* MXCSR */
 325   context_offset (ExtendedRegisters[24])
 326 };
 327 #undef context_offset
 328
 329 #else /* __x86_64__ */
 330
 331 #define context_offset(x) (offsetof (CONTEXT, x))
 332 static const int mappings[] =
 333 {
 334   context_offset (Rax),
 335   context_offset (Rbx),
 336   context_offset (Rcx),
 337   context_offset (Rdx),
 338   context_offset (Rsi),
 339   context_offset (Rdi),
 340   context_offset (Rbp),
 341   context_offset (Rsp),
 342   context_offset (R8),
 343   context_offset (R9),
 344   context_offset (R10),
 345   context_offset (R11),
 346   context_offset (R12),
 347   context_offset (R13),
 348   context_offset (R14),
 349   context_offset (R15),
 350   context_offset (Rip),
 351   context_offset (EFlags),
 352   context_offset (SegCs),
 353   context_offset (SegSs),
 354   context_offset (SegDs),
 355   context_offset (SegEs),
 356   context_offset (SegFs),
 357   context_offset (SegGs),
 358   context_offset (FloatSave.FloatRegisters[0]),
 359   context_offset (FloatSave.FloatRegisters[1]),
 360   context_offset (FloatSave.FloatRegisters[2]),
 361   context_offset (FloatSave.FloatRegisters[3]),
 362   context_offset (FloatSave.FloatRegisters[4]),
 363   context_offset (FloatSave.FloatRegisters[5]),
 364   context_offset (FloatSave.FloatRegisters[6]),
 365   context_offset (FloatSave.FloatRegisters[7]),
 366   context_offset (FloatSave.ControlWord),
 367   context_offset (FloatSave.StatusWord),
 368   context_offset (FloatSave.TagWord),
 369   context_offset (FloatSave.ErrorSelector),
 370   context_offset (FloatSave.ErrorOffset),
 371   context_offset (FloatSave.DataSelector),
 372   context_offset (FloatSave.DataOffset),
 373   context_offset (FloatSave.ErrorSelector)
 374   /* XMM0-7 */ ,
 375   context_offset (Xmm0),
 376   context_offset (Xmm1),
 377   context_offset (Xmm2),
 378   context_offset (Xmm3),
 379   context_offset (Xmm4),
 380   context_offset (Xmm5),
 381   context_offset (Xmm6),
 382   context_offset (Xmm7),
 383   context_offset (Xmm8),
 384   context_offset (Xmm9),
 385   context_offset (Xmm10),
 386   context_offset (Xmm11),
 387   context_offset (Xmm12),
 388   context_offset (Xmm13),
 389   context_offset (Xmm14),
 390   context_offset (Xmm15),
 391   /* MXCSR */
 392   context_offset (FloatSave.MxCsr)
 393 };
 394 #undef context_offset
 395
 396 #endif /* __x86_64__ */
 397
 398 /* Fetch register from gdbserver regcache data.  */
 399 static void
 400 i386_fetch_inferior_register (struct regcache *regcache,
 401                               win32_thread_info *th, int r)
 402 {
 403   char *context_offset = (char *) &th->context + mappings[r];
 404
 405   long l;
 406   if (r == FCS_REGNUM)
 407     {
 408       l = *((long *) context_offset) & 0xffff;
 409       supply_register (regcache, r, (char *) &l);
 410     }
 411   else if (r == FOP_REGNUM)
 412     {
 413       l = (*((long *) context_offset) >> 16) & ((1 << 11) - 1);
 414       supply_register (regcache, r, (char *) &l);
 415     }
 416   else
 417     supply_register (regcache, r, context_offset);
 418 }
 419
 420 /* Store a new register value into the thread context of TH.  */
 421 static void
 422 i386_store_inferior_register (struct regcache *regcache,
 423                               win32_thread_info *th, int r)
 424 {
 425   char *context_offset = (char *) &th->context + mappings[r];
 426   collect_register (regcache, r, context_offset);
 427 }
 428
 429 static const unsigned char i386_win32_breakpoint = 0xcc;
 430 #define i386_win32_breakpoint_len 1
 431
 432 static void
 433 i386_arch_setup (void)
 434 {
 435   struct target_desc *tdesc;
 436
 437 #ifdef __x86_64__
 438   tdesc = amd64_create_target_description (X86_XSTATE_SSE_MASK, false,
 439                                            false, false);
 440   const char **expedite_regs = amd64_expedite_regs;
 441 #else
 442   tdesc = i386_create_target_description (X86_XSTATE_SSE_MASK, false, false);
 443   const char **expedite_regs = i386_expedite_regs;
 444 #endif
 445
 446   init_target_desc (tdesc, expedite_regs);
 447
 448   win32_tdesc = tdesc;
 449 }
 450
 451 struct win32_target_ops the_low_target = {
 452   i386_arch_setup,
 453   sizeof (mappings) / sizeof (mappings[0]),
 454   i386_initial_stuff,
 455   i386_get_thread_context,
 456   i386_prepare_to_resume,
 457   i386_thread_added,
 458   i386_fetch_inferior_register,
 459   i386_store_inferior_register,
 460   i386_single_step,
 461   &i386_win32_breakpoint,
 462   i386_win32_breakpoint_len,
 463   i386_supports_z_point_type,
 464   i386_insert_point,
 465   i386_remove_point,
 466   x86_stopped_by_watchpoint,
 467   x86_stopped_data_address
 468 };