gdb/i386-gnu-nat.c

   1 /* Low level interface to i386 running the GNU Hurd.
   2
   3    Copyright (C) 1992-2018 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 /* Mach/Hurd headers are not yet ready for C++ compilation.  */
  21 extern "C"
  22 {
  23 #include <mach.h>
  24 #include <mach_error.h>
  25 #include <mach/message.h>
  26 #include <mach/exception.h>
  27 }
  28
  29 #include "defs.h"
  30 #include "x86-nat.h"
  31 #include "inferior.h"
  32 #include "floatformat.h"
  33 #include "regcache.h"
  34
  35 #include "i386-tdep.h"
  36
  37 #include "gnu-nat.h"
  38 #include "inf-child.h"
  39 #include "i387-tdep.h"
  40
  41 /* Offset to the thread_state_t location where REG is stored.  */
  42 #define REG_OFFSET(reg) offsetof (struct i386_thread_state, reg)
  43
  44 /* At REG_OFFSET[N] is the offset to the thread_state_t location where
  45    the GDB register N is stored.  */
  46 static int reg_offset[] =
  47 {
  48   REG_OFFSET (eax), REG_OFFSET (ecx), REG_OFFSET (edx), REG_OFFSET (ebx),
  49   REG_OFFSET (uesp), REG_OFFSET (ebp), REG_OFFSET (esi), REG_OFFSET (edi),
  50   REG_OFFSET (eip), REG_OFFSET (efl), REG_OFFSET (cs), REG_OFFSET (ss),
  51   REG_OFFSET (ds), REG_OFFSET (es), REG_OFFSET (fs), REG_OFFSET (gs)
  52 };
  53
  54 #define REG_ADDR(state, regnum) ((char *)(state) + reg_offset[regnum])
  55
  56 \f
  57
  58 /* The i386 GNU Hurd target.  */
  59
  60 #ifdef i386_DEBUG_STATE
  61 using gnu_base_target = x86_nat_target<gnu_nat_target>;
  62 #else
  63 using gnu_base_target = gnu_nat_target;
  64 #endif
  65
  66 struct i386_gnu_nat_target final : public gnu_base_target
  67 {
  68   void fetch_registers (struct regcache *, int) override;
  69   void store_registers (struct regcache *, int) override;
  70 };
  71
  72 static i386_gnu_nat_target the_i386_gnu_nat_target;
  73
  74 /* Get the whole floating-point state of THREAD and record the values
  75    of the corresponding (pseudo) registers.  */
  76
  77 static void
  78 fetch_fpregs (struct regcache *regcache, struct proc *thread)
  79 {
  80   mach_msg_type_number_t count = i386_FLOAT_STATE_COUNT;
  81   struct i386_float_state state;
  82   kern_return_t err;
  83
  84   err = thread_get_state (thread->port, i386_FLOAT_STATE,
  85                           (thread_state_t) &state, &count);
  86   if (err)
  87     {
  88       warning (_("Couldn't fetch floating-point state from %s"),
  89                proc_string (thread));
  90       return;
  91     }
  92
  93   if (!state.initialized)
  94     {
  95       /* The floating-point state isn't initialized.  */
  96       i387_supply_fsave (regcache, -1, NULL);
  97     }
  98   else
  99     {
 100       /* Supply the floating-point registers.  */
 101       i387_supply_fsave (regcache, -1, state.hw_state);
 102     }
 103 }
 104
 105 /* Fetch register REGNO, or all regs if REGNO is -1.  */
 106 static void
 107 gnu_fetch_registers (struct target_ops *ops,
 108                      struct regcache *regcache, int regno)
 109 {
 110   struct proc *thread;
 111   ptid_t ptid = regcache->ptid ();
 112
 113   /* Make sure we know about new threads.  */
 114   inf_update_procs (gnu_current_inf);
 115
 116   thread = inf_tid_to_thread (gnu_current_inf, ptid_get_lwp (ptid));
 117   if (!thread)
 118     error (_("Can't fetch registers from thread %s: No such thread"),
 119            target_pid_to_str (ptid));
 120
 121   if (regno < I386_NUM_GREGS || regno == -1)
 122     {
 123       thread_state_t state;
 124
 125       /* This does the dirty work for us.  */
 126       state = proc_get_state (thread, 0);
 127       if (!state)
 128         {
 129           warning (_("Couldn't fetch registers from %s"),
 130                    proc_string (thread));
 131           return;
 132         }
 133
 134       if (regno == -1)
 135         {
 136           int i;
 137
 138           proc_debug (thread, "fetching all register");
 139
 140           for (i = 0; i < I386_NUM_GREGS; i++)
 141             regcache_raw_supply (regcache, i, REG_ADDR (state, i));
 142           thread->fetched_regs = ~0;
 143         }
 144       else
 145         {
 146           proc_debug (thread, "fetching register %s",
 147                       gdbarch_register_name (regcache->arch (),
 148                                              regno));
 149
 150           regcache_raw_supply (regcache, regno,
 151                                REG_ADDR (state, regno));
 152           thread->fetched_regs |= (1 << regno);
 153         }
 154     }
 155
 156   if (regno >= I386_NUM_GREGS || regno == -1)
 157     {
 158       proc_debug (thread, "fetching floating-point registers");
 159
 160       fetch_fpregs (regcache, thread);
 161     }
 162 }
 163 \f
 164
 165 /* Store the whole floating-point state into THREAD using information
 166    from the corresponding (pseudo) registers.  */
 167 static void
 168 store_fpregs (const struct regcache *regcache, struct proc *thread, int regno)
 169 {
 170   mach_msg_type_number_t count = i386_FLOAT_STATE_COUNT;
 171   struct i386_float_state state;
 172   kern_return_t err;
 173
 174   err = thread_get_state (thread->port, i386_FLOAT_STATE,
 175                           (thread_state_t) &state, &count);
 176   if (err)
 177     {
 178       warning (_("Couldn't fetch floating-point state from %s"),
 179                proc_string (thread));
 180       return;
 181     }
 182
 183   /* FIXME: kettenis/2001-07-15: Is this right?  Should we somehow
 184      take into account DEPRECATED_REGISTER_VALID like the old code did?  */
 185   i387_collect_fsave (regcache, regno, state.hw_state);
 186
 187   err = thread_set_state (thread->port, i386_FLOAT_STATE,
 188                           (thread_state_t) &state, i386_FLOAT_STATE_COUNT);
 189   if (err)
 190     {
 191       warning (_("Couldn't store floating-point state into %s"),
 192                proc_string (thread));
 193       return;
 194     }
 195 }
 196
 197 /* Store at least register REGNO, or all regs if REGNO == -1.  */
 198 static void
 199 gnu_store_registers (struct target_ops *ops,
 200                      struct regcache *regcache, int regno)
 201 {
 202   struct proc *thread;
 203   struct gdbarch *gdbarch = regcache->arch ();
 204   ptid_t ptid = regcache->ptid ();
 205
 206   /* Make sure we know about new threads.  */
 207   inf_update_procs (gnu_current_inf);
 208
 209   thread = inf_tid_to_thread (gnu_current_inf, ptid_get_lwp (ptid));
 210   if (!thread)
 211     error (_("Couldn't store registers into thread %s: No such thread"),
 212            target_pid_to_str (ptid));
 213
 214   if (regno < I386_NUM_GREGS || regno == -1)
 215     {
 216       thread_state_t state;
 217       thread_state_data_t old_state;
 218       int was_aborted = thread->aborted;
 219       int was_valid = thread->state_valid;
 220       int trace;
 221
 222       if (!was_aborted && was_valid)
 223         memcpy (&old_state, &thread->state, sizeof (old_state));
 224
 225       state = proc_get_state (thread, 1);
 226       if (!state)
 227         {
 228           warning (_("Couldn't store registers into %s"),
 229                    proc_string (thread));
 230           return;
 231         }
 232
 233       /* Save the T bit.  We might try to restore the %eflags register
 234          below, but changing the T bit would seriously confuse GDB.  */
 235       trace = ((struct i386_thread_state *)state)->efl & 0x100;
 236
 237       if (!was_aborted && was_valid)
 238         /* See which registers have changed after aborting the thread.  */
 239         {
 240           int check_regno;
 241
 242           for (check_regno = 0; check_regno < I386_NUM_GREGS; check_regno++)
 243             if ((thread->fetched_regs & (1 << check_regno))
 244                 && memcpy (REG_ADDR (&old_state, check_regno),
 245                            REG_ADDR (state, check_regno),
 246                            register_size (gdbarch, check_regno)))
 247               /* Register CHECK_REGNO has changed!  Ack!  */
 248               {
 249                 warning (_("Register %s changed after the thread was aborted"),
 250                          gdbarch_register_name (gdbarch, check_regno));
 251                 if (regno >= 0 && regno != check_regno)
 252                   /* Update GDB's copy of the register.  */
 253                   regcache_raw_supply (regcache, check_regno,
 254                                        REG_ADDR (state, check_regno));
 255                 else
 256                   warning (_("... also writing this register!  "
 257                              "Suspicious..."));
 258               }
 259         }
 260
 261       if (regno == -1)
 262         {
 263           int i;
 264
 265           proc_debug (thread, "storing all registers");
 266
 267           for (i = 0; i < I386_NUM_GREGS; i++)
 268             if (REG_VALID == regcache_register_status (regcache, i))
 269               regcache_raw_collect (regcache, i, REG_ADDR (state, i));
 270         }
 271       else
 272         {
 273           proc_debug (thread, "storing register %s",
 274                       gdbarch_register_name (gdbarch, regno));
 275
 276           gdb_assert (REG_VALID == regcache_register_status (regcache, regno));
 277           regcache_raw_collect (regcache, regno, REG_ADDR (state, regno));
 278         }
 279
 280       /* Restore the T bit.  */
 281       ((struct i386_thread_state *)state)->efl &= ~0x100;
 282       ((struct i386_thread_state *)state)->efl |= trace;
 283     }
 284
 285   if (regno >= I386_NUM_GREGS || regno == -1)
 286     {
 287       proc_debug (thread, "storing floating-point registers");
 288
 289       store_fpregs (regcache, thread, regno);
 290     }
 291 }
 292
 293 \f
 294 /* Support for debug registers.  */
 295
 296 #ifdef i386_DEBUG_STATE
 297 /* Get debug registers for thread THREAD.  */
 298
 299 static void
 300 i386_gnu_dr_get (struct i386_debug_state *regs, struct proc *thread)
 301 {
 302   mach_msg_type_number_t count = i386_DEBUG_STATE_COUNT;
 303   kern_return_t err;
 304
 305   err = thread_get_state (thread->port, i386_DEBUG_STATE,
 306                           (thread_state_t) regs, &count);
 307   if (err != 0 || count != i386_DEBUG_STATE_COUNT)
 308     warning (_("Couldn't fetch debug state from %s"),
 309              proc_string (thread));
 310 }
 311
 312 /* Set debug registers for thread THREAD.  */
 313
 314 static void
 315 i386_gnu_dr_set (const struct i386_debug_state *regs, struct proc *thread)
 316 {
 317   kern_return_t err;
 318
 319   err = thread_set_state (thread->port, i386_DEBUG_STATE,
 320                           (thread_state_t) regs, i386_DEBUG_STATE_COUNT);
 321   if (err != 0)
 322     warning (_("Couldn't store debug state into %s"),
 323              proc_string (thread));
 324 }
 325
 326 /* Set DR_CONTROL in THREAD.  */
 327
 328 static void
 329 i386_gnu_dr_set_control_one (struct proc *thread, void *arg)
 330 {
 331   unsigned long *control = (unsigned long *) arg;
 332   struct i386_debug_state regs;
 333
 334   i386_gnu_dr_get (&regs, thread);
 335   regs.dr[DR_CONTROL] = *control;
 336   i386_gnu_dr_set (&regs, thread);
 337 }
 338
 339 /* Set DR_CONTROL to CONTROL in all threads.  */
 340
 341 static void
 342 i386_gnu_dr_set_control (unsigned long control)
 343 {
 344   inf_update_procs (gnu_current_inf);
 345   inf_threads (gnu_current_inf, i386_gnu_dr_set_control_one, &control);
 346 }
 347
 348 /* Parameters to set a debugging address.  */
 349
 350 struct reg_addr
 351 {
 352   int regnum;           /* Register number (zero based).  */
 353   CORE_ADDR addr;       /* Address.  */
 354 };
 355
 356 /* Set address REGNUM (zero based) to ADDR in THREAD.  */
 357
 358 static void
 359 i386_gnu_dr_set_addr_one (struct proc *thread, void *arg)
 360 {
 361   struct reg_addr *reg_addr = (struct reg_addr *) arg;
 362   struct i386_debug_state regs;
 363
 364   i386_gnu_dr_get (&regs, thread);
 365   regs.dr[reg_addr->regnum] = reg_addr->addr;
 366   i386_gnu_dr_set (&regs, thread);
 367 }
 368
 369 /* Set address REGNUM (zero based) to ADDR in all threads.  */
 370
 371 static void
 372 i386_gnu_dr_set_addr (int regnum, CORE_ADDR addr)
 373 {
 374   struct reg_addr reg_addr;
 375
 376   gdb_assert (DR_FIRSTADDR <= regnum && regnum <= DR_LASTADDR);
 377
 378   reg_addr.regnum = regnum;
 379   reg_addr.addr = addr;
 380
 381   inf_update_procs (gnu_current_inf);
 382   inf_threads (gnu_current_inf, i386_gnu_dr_set_addr_one, &reg_addr);
 383 }
 384
 385 /* Get debug register REGNUM value from only the one LWP of PTID.  */
 386
 387 static unsigned long
 388 i386_gnu_dr_get_reg (ptid_t ptid, int regnum)
 389 {
 390   struct i386_debug_state regs;
 391   struct proc *thread;
 392
 393   /* Make sure we know about new threads.  */
 394   inf_update_procs (gnu_current_inf);
 395
 396   thread = inf_tid_to_thread (gnu_current_inf, ptid_get_lwp (ptid));
 397   i386_gnu_dr_get (&regs, thread);
 398
 399   return regs.dr[regnum];
 400 }
 401
 402 /* Return the inferior's debug register REGNUM.  */
 403
 404 static CORE_ADDR
 405 i386_gnu_dr_get_addr (int regnum)
 406 {
 407   gdb_assert (DR_FIRSTADDR <= regnum && regnum <= DR_LASTADDR);
 408
 409   return i386_gnu_dr_get_reg (inferior_ptid, regnum);
 410 }
 411
 412 /* Get DR_STATUS from only the one thread of INFERIOR_PTID.  */
 413
 414 static unsigned long
 415 i386_gnu_dr_get_status (void)
 416 {
 417   return i386_gnu_dr_get_reg (inferior_ptid, DR_STATUS);
 418 }
 419
 420 /* Return the inferior's DR7 debug control register.  */
 421
 422 static unsigned long
 423 i386_gnu_dr_get_control (void)
 424 {
 425   return i386_gnu_dr_get_reg (inferior_ptid, DR_CONTROL);
 426 }
 427 #endif /* i386_DEBUG_STATE */
 428
 429 void
 430 _initialize_i386gnu_nat (void)
 431 {
 432 #ifdef i386_DEBUG_STATE
 433   x86_dr_low.set_control = i386_gnu_dr_set_control;
 434   gdb_assert (DR_FIRSTADDR == 0 && DR_LASTADDR < i386_DEBUG_STATE_COUNT);
 435   x86_dr_low.set_addr = i386_gnu_dr_set_addr;
 436   x86_dr_low.get_addr = i386_gnu_dr_get_addr;
 437   x86_dr_low.get_status = i386_gnu_dr_get_status;
 438   x86_dr_low.get_control = i386_gnu_dr_get_control;
 439   x86_set_debug_register_length (4);
 440 #endif /* i386_DEBUG_STATE */
 441
 442   /* Register the target.  */
 443   add_inf_child_target (&the_i386_gnu_nat_target);
 444 }