gdb/i386-gnu-nat.c

   1 /* Low level interface to i386 running the GNU Hurd.
   2
   3    Copyright (C) 1992-2016 Free Software Foundation, Inc.
   4
   5    This file is part of GDB.
   6
   7    This program is free software; you can redistribute it and/or modify
   8    it under the terms of the GNU General Public License as published by
   9    the Free Software Foundation; either version 3 of the License, or
  10    (at your option) any later version.
  11
  12    This program is distributed in the hope that it will be useful,
  13    but WITHOUT ANY WARRANTY; without even the implied warranty of
  14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15    GNU General Public License for more details.
  16
  17    You should have received a copy of the GNU General Public License
  18    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
  19
  20 #include "defs.h"
  21 #include "x86-nat.h"
  22 #include "inferior.h"
  23 #include "floatformat.h"
  24 #include "regcache.h"
  25
  26 #include <mach.h>
  27 #include <mach_error.h>
  28 #include <mach/message.h>
  29 #include <mach/exception.h>
  30
  31 #include "i386-tdep.h"
  32
  33 #include "gnu-nat.h"
  34 #include "inf-child.h"
  35 #include "i387-tdep.h"
  36
  37 /* Offset to the thread_state_t location where REG is stored.  */
  38 #define REG_OFFSET(reg) offsetof (struct i386_thread_state, reg)
  39
  40 /* At REG_OFFSET[N] is the offset to the thread_state_t location where
  41    the GDB register N is stored.  */
  42 static int reg_offset[] =
  43 {
  44   REG_OFFSET (eax), REG_OFFSET (ecx), REG_OFFSET (edx), REG_OFFSET (ebx),
  45   REG_OFFSET (uesp), REG_OFFSET (ebp), REG_OFFSET (esi), REG_OFFSET (edi),
  46   REG_OFFSET (eip), REG_OFFSET (efl), REG_OFFSET (cs), REG_OFFSET (ss),
  47   REG_OFFSET (ds), REG_OFFSET (es), REG_OFFSET (fs), REG_OFFSET (gs)
  48 };
  49
  50 #define REG_ADDR(state, regnum) ((char *)(state) + reg_offset[regnum])
  51
  52 \f
  53 /* Get the whole floating-point state of THREAD and record the values
  54    of the corresponding (pseudo) registers.  */
  55
  56 static void
  57 fetch_fpregs (struct regcache *regcache, struct proc *thread)
  58 {
  59   mach_msg_type_number_t count = i386_FLOAT_STATE_COUNT;
  60   struct i386_float_state state;
  61   kern_return_t err;
  62
  63   err = thread_get_state (thread->port, i386_FLOAT_STATE,
  64                           (thread_state_t) &state, &count);
  65   if (err)
  66     {
  67       warning (_("Couldn't fetch floating-point state from %s"),
  68                proc_string (thread));
  69       return;
  70     }
  71
  72   if (!state.initialized)
  73     {
  74       /* The floating-point state isn't initialized.  */
  75       i387_supply_fsave (regcache, -1, NULL);
  76     }
  77   else
  78     {
  79       /* Supply the floating-point registers.  */
  80       i387_supply_fsave (regcache, -1, state.hw_state);
  81     }
  82 }
  83
  84 /* Fetch register REGNO, or all regs if REGNO is -1.  */
  85 static void
  86 gnu_fetch_registers (struct target_ops *ops,
  87                      struct regcache *regcache, int regno)
  88 {
  89   struct proc *thread;
  90
  91   /* Make sure we know about new threads.  */
  92   inf_update_procs (gnu_current_inf);
  93
  94   thread = inf_tid_to_thread (gnu_current_inf,
  95                               ptid_get_lwp (inferior_ptid));
  96   if (!thread)
  97     error (_("Can't fetch registers from thread %s: No such thread"),
  98            target_pid_to_str (inferior_ptid));
  99
 100   if (regno < I386_NUM_GREGS || regno == -1)
 101     {
 102       thread_state_t state;
 103
 104       /* This does the dirty work for us.  */
 105       state = proc_get_state (thread, 0);
 106       if (!state)
 107         {
 108           warning (_("Couldn't fetch registers from %s"),
 109                    proc_string (thread));
 110           return;
 111         }
 112
 113       if (regno == -1)
 114         {
 115           int i;
 116
 117           proc_debug (thread, "fetching all register");
 118
 119           for (i = 0; i < I386_NUM_GREGS; i++)
 120             regcache_raw_supply (regcache, i, REG_ADDR (state, i));
 121           thread->fetched_regs = ~0;
 122         }
 123       else
 124         {
 125           proc_debug (thread, "fetching register %s",
 126                       gdbarch_register_name (get_regcache_arch (regcache),
 127                                              regno));
 128
 129           regcache_raw_supply (regcache, regno,
 130                                REG_ADDR (state, regno));
 131           thread->fetched_regs |= (1 << regno);
 132         }
 133     }
 134
 135   if (regno >= I386_NUM_GREGS || regno == -1)
 136     {
 137       proc_debug (thread, "fetching floating-point registers");
 138
 139       fetch_fpregs (regcache, thread);
 140     }
 141 }
 142 \f
 143
 144 /* Store the whole floating-point state into THREAD using information
 145    from the corresponding (pseudo) registers.  */
 146 static void
 147 store_fpregs (const struct regcache *regcache, struct proc *thread, int regno)
 148 {
 149   mach_msg_type_number_t count = i386_FLOAT_STATE_COUNT;
 150   struct i386_float_state state;
 151   kern_return_t err;
 152
 153   err = thread_get_state (thread->port, i386_FLOAT_STATE,
 154                           (thread_state_t) &state, &count);
 155   if (err)
 156     {
 157       warning (_("Couldn't fetch floating-point state from %s"),
 158                proc_string (thread));
 159       return;
 160     }
 161
 162   /* FIXME: kettenis/2001-07-15: Is this right?  Should we somehow
 163      take into account DEPRECATED_REGISTER_VALID like the old code did?  */
 164   i387_collect_fsave (regcache, regno, state.hw_state);
 165
 166   err = thread_set_state (thread->port, i386_FLOAT_STATE,
 167                           (thread_state_t) &state, i386_FLOAT_STATE_COUNT);
 168   if (err)
 169     {
 170       warning (_("Couldn't store floating-point state into %s"),
 171                proc_string (thread));
 172       return;
 173     }
 174 }
 175
 176 /* Store at least register REGNO, or all regs if REGNO == -1.  */
 177 static void
 178 gnu_store_registers (struct target_ops *ops,
 179                      struct regcache *regcache, int regno)
 180 {
 181   struct proc *thread;
 182   struct gdbarch *gdbarch = get_regcache_arch (regcache);
 183
 184   /* Make sure we know about new threads.  */
 185   inf_update_procs (gnu_current_inf);
 186
 187   thread = inf_tid_to_thread (gnu_current_inf,
 188                               ptid_get_lwp (inferior_ptid));
 189   if (!thread)
 190     error (_("Couldn't store registers into thread %s: No such thread"),
 191            target_pid_to_str (inferior_ptid));
 192
 193   if (regno < I386_NUM_GREGS || regno == -1)
 194     {
 195       thread_state_t state;
 196       thread_state_data_t old_state;
 197       int was_aborted = thread->aborted;
 198       int was_valid = thread->state_valid;
 199       int trace;
 200
 201       if (!was_aborted && was_valid)
 202         memcpy (&old_state, &thread->state, sizeof (old_state));
 203
 204       state = proc_get_state (thread, 1);
 205       if (!state)
 206         {
 207           warning (_("Couldn't store registers into %s"),
 208                    proc_string (thread));
 209           return;
 210         }
 211
 212       /* Save the T bit.  We might try to restore the %eflags register
 213          below, but changing the T bit would seriously confuse GDB.  */
 214       trace = ((struct i386_thread_state *)state)->efl & 0x100;
 215
 216       if (!was_aborted && was_valid)
 217         /* See which registers have changed after aborting the thread.  */
 218         {
 219           int check_regno;
 220
 221           for (check_regno = 0; check_regno < I386_NUM_GREGS; check_regno++)
 222             if ((thread->fetched_regs & (1 << check_regno))
 223                 && memcpy (REG_ADDR (&old_state, check_regno),
 224                            REG_ADDR (state, check_regno),
 225                            register_size (gdbarch, check_regno)))
 226               /* Register CHECK_REGNO has changed!  Ack!  */
 227               {
 228                 warning (_("Register %s changed after the thread was aborted"),
 229                          gdbarch_register_name (gdbarch, check_regno));
 230                 if (regno >= 0 && regno != check_regno)
 231                   /* Update GDB's copy of the register.  */
 232                   regcache_raw_supply (regcache, check_regno,
 233                                        REG_ADDR (state, check_regno));
 234                 else
 235                   warning (_("... also writing this register!  "
 236                              "Suspicious..."));
 237               }
 238         }
 239
 240       if (regno == -1)
 241         {
 242           int i;
 243
 244           proc_debug (thread, "storing all registers");
 245
 246           for (i = 0; i < I386_NUM_GREGS; i++)
 247             if (REG_VALID == regcache_register_status (regcache, i))
 248               regcache_raw_collect (regcache, i, REG_ADDR (state, i));
 249         }
 250       else
 251         {
 252           proc_debug (thread, "storing register %s",
 253                       gdbarch_register_name (gdbarch, regno));
 254
 255           gdb_assert (REG_VALID == regcache_register_status (regcache, regno));
 256           regcache_raw_collect (regcache, regno, REG_ADDR (state, regno));
 257         }
 258
 259       /* Restore the T bit.  */
 260       ((struct i386_thread_state *)state)->efl &= ~0x100;
 261       ((struct i386_thread_state *)state)->efl |= trace;
 262     }
 263
 264   if (regno >= I386_NUM_GREGS || regno == -1)
 265     {
 266       proc_debug (thread, "storing floating-point registers");
 267
 268       store_fpregs (regcache, thread, regno);
 269     }
 270 }
 271
 272 \f
 273 /* Support for debug registers.  */
 274
 275 #ifdef i386_DEBUG_STATE
 276 /* Get debug registers for thread THREAD.  */
 277
 278 static void
 279 i386_gnu_dr_get (struct i386_debug_state *regs, struct proc *thread)
 280 {
 281   mach_msg_type_number_t count = i386_DEBUG_STATE_COUNT;
 282   kern_return_t err;
 283
 284   err = thread_get_state (thread->port, i386_DEBUG_STATE,
 285                           (thread_state_t) regs, &count);
 286   if (err != 0 || count != i386_DEBUG_STATE_COUNT)
 287     warning (_("Couldn't fetch debug state from %s"),
 288              proc_string (thread));
 289 }
 290
 291 /* Set debug registers for thread THREAD.  */
 292
 293 static void
 294 i386_gnu_dr_set (const struct i386_debug_state *regs, struct proc *thread)
 295 {
 296   kern_return_t err;
 297
 298   err = thread_set_state (thread->port, i386_DEBUG_STATE,
 299                           (thread_state_t) regs, i386_DEBUG_STATE_COUNT);
 300   if (err != 0)
 301     warning (_("Couldn't store debug state into %s"),
 302              proc_string (thread));
 303 }
 304
 305 /* Set DR_CONTROL in THREAD.  */
 306
 307 static void
 308 i386_gnu_dr_set_control_one (struct proc *thread, void *arg)
 309 {
 310   unsigned long *control = (unsigned long *) arg;
 311   struct i386_debug_state regs;
 312
 313   i386_gnu_dr_get (&regs, thread);
 314   regs.dr[DR_CONTROL] = *control;
 315   i386_gnu_dr_set (&regs, thread);
 316 }
 317
 318 /* Set DR_CONTROL to CONTROL in all threads.  */
 319
 320 static void
 321 i386_gnu_dr_set_control (unsigned long control)
 322 {
 323   inf_update_procs (gnu_current_inf);
 324   inf_threads (gnu_current_inf, i386_gnu_dr_set_control_one, &control);
 325 }
 326
 327 /* Parameters to set a debugging address.  */
 328
 329 struct reg_addr
 330 {
 331   int regnum;           /* Register number (zero based).  */
 332   CORE_ADDR addr;       /* Address.  */
 333 };
 334
 335 /* Set address REGNUM (zero based) to ADDR in THREAD.  */
 336
 337 static void
 338 i386_gnu_dr_set_addr_one (struct proc *thread, void *arg)
 339 {
 340   struct reg_addr *reg_addr = (struct reg_addr *) arg;
 341   struct i386_debug_state regs;
 342
 343   i386_gnu_dr_get (&regs, thread);
 344   regs.dr[reg_addr->regnum] = reg_addr->addr;
 345   i386_gnu_dr_set (&regs, thread);
 346 }
 347
 348 /* Set address REGNUM (zero based) to ADDR in all threads.  */
 349
 350 static void
 351 i386_gnu_dr_set_addr (int regnum, CORE_ADDR addr)
 352 {
 353   struct reg_addr reg_addr;
 354
 355   gdb_assert (DR_FIRSTADDR <= regnum && regnum <= DR_LASTADDR);
 356
 357   reg_addr.regnum = regnum;
 358   reg_addr.addr = addr;
 359
 360   inf_update_procs (gnu_current_inf);
 361   inf_threads (gnu_current_inf, i386_gnu_dr_set_addr_one, &reg_addr);
 362 }
 363
 364 /* Get debug register REGNUM value from only the one LWP of PTID.  */
 365
 366 static unsigned long
 367 i386_gnu_dr_get_reg (ptid_t ptid, int regnum)
 368 {
 369   struct i386_debug_state regs;
 370   struct proc *thread;
 371
 372   /* Make sure we know about new threads.  */
 373   inf_update_procs (gnu_current_inf);
 374
 375   thread = inf_tid_to_thread (gnu_current_inf, ptid_get_lwp (ptid));
 376   i386_gnu_dr_get (&regs, thread);
 377
 378   return regs.dr[regnum];
 379 }
 380
 381 /* Return the inferior's debug register REGNUM.  */
 382
 383 static CORE_ADDR
 384 i386_gnu_dr_get_addr (int regnum)
 385 {
 386   gdb_assert (DR_FIRSTADDR <= regnum && regnum <= DR_LASTADDR);
 387
 388   return i386_gnu_dr_get_reg (inferior_ptid, regnum);
 389 }
 390
 391 /* Get DR_STATUS from only the one thread of INFERIOR_PTID.  */
 392
 393 static unsigned long
 394 i386_gnu_dr_get_status (void)
 395 {
 396   return i386_gnu_dr_get_reg (inferior_ptid, DR_STATUS);
 397 }
 398
 399 /* Return the inferior's DR7 debug control register.  */
 400
 401 static unsigned long
 402 i386_gnu_dr_get_control (void)
 403 {
 404   return i386_gnu_dr_get_reg (inferior_ptid, DR_CONTROL);
 405 }
 406 #endif /* i386_DEBUG_STATE */
 407
 408 /* Provide a prototype to silence -Wmissing-prototypes.  */
 409 extern initialize_file_ftype _initialize_i386gnu_nat;
 410
 411 void
 412 _initialize_i386gnu_nat (void)
 413 {
 414   struct target_ops *t;
 415
 416   /* Fill in the generic GNU/Hurd methods.  */
 417   t = gnu_target ();
 418
 419 #ifdef i386_DEBUG_STATE
 420   x86_use_watchpoints (t);
 421
 422   x86_dr_low.set_control = i386_gnu_dr_set_control;
 423   gdb_assert (DR_FIRSTADDR == 0 && DR_LASTADDR < i386_DEBUG_STATE_COUNT);
 424   x86_dr_low.set_addr = i386_gnu_dr_set_addr;
 425   x86_dr_low.get_addr = i386_gnu_dr_get_addr;
 426   x86_dr_low.get_status = i386_gnu_dr_get_status;
 427   x86_dr_low.get_control = i386_gnu_dr_get_control;
 428   x86_set_debug_register_length (4);
 429 #endif /* i386_DEBUG_STATE */
 430
 431   t->to_fetch_registers = gnu_fetch_registers;
 432   t->to_store_registers = gnu_store_registers;
 433
 434   /* Register the target.  */
 435   add_target (t);
 436 }