gdb/mips-linux-nat.c

   1 /* Native-dependent code for GNU/Linux on MIPS processors.
   2
   3    Copyright (C) 2001-2018 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 #include "defs.h"
  21 #include "command.h"
  22 #include "gdbcmd.h"
  23 #include "inferior.h"
  24 #include "mips-tdep.h"
  25 #include "target.h"
  26 #include "regcache.h"
  27 #include "linux-nat-trad.h"
  28 #include "mips-linux-tdep.h"
  29 #include "target-descriptions.h"
  30
  31 #include "gdb_proc_service.h"
  32 #include "gregset.h"
  33
  34 #include <sgidefs.h>
  35 #include "nat/gdb_ptrace.h"
  36 #include <asm/ptrace.h>
  37 #include "inf-ptrace.h"
  38
  39 #include "nat/mips-linux-watch.h"
  40
  41 #ifndef PTRACE_GET_THREAD_AREA
  42 #define PTRACE_GET_THREAD_AREA 25
  43 #endif
  44
  45 class mips_linux_nat_target final : public linux_nat_trad_target
  46 {
  47 public:
  48   /* Add our register access methods.  */
  49   void fetch_registers (struct regcache *, int) override;
  50   void store_registers (struct regcache *, int) override;
  51
  52   void close () override;
  53
  54   int can_use_hw_breakpoint (enum bptype, int, int) override;
  55
  56   int remove_watchpoint (CORE_ADDR, int, enum target_hw_bp_type,
  57                          struct expression *) override;
  58
  59   int insert_watchpoint (CORE_ADDR, int, enum target_hw_bp_type,
  60                          struct expression *) override;
  61
  62   bool stopped_by_watchpoint () override;
  63
  64   bool stopped_data_address (CORE_ADDR *) override;
  65
  66   int region_ok_for_hw_watchpoint (CORE_ADDR, int) override;
  67
  68   const struct target_desc *read_description () override;
  69
  70 protected:
  71   /* Override linux_nat_trad_target methods.  */
  72   CORE_ADDR register_u_offset (struct gdbarch *gdbarch,
  73                                int regno, int store_p) override;
  74
  75   /* Override linux_nat_target low methods.  */
  76   void low_new_thread (struct lwp_info *lp) override;
  77
  78 private:
  79   /* Helpers.  See definitions.  */
  80   void mips64_regsets_store_registers (struct regcache *regcache,
  81                                        int regno);
  82   void mips64_regsets_fetch_registers (struct regcache *regcache,
  83                                        int regno);
  84 };
  85
  86 static mips_linux_nat_target the_mips_linux_nat_target;
  87
  88 /* Assume that we have PTRACE_GETREGS et al. support.  If we do not,
  89    we'll clear this and use PTRACE_PEEKUSER instead.  */
  90 static int have_ptrace_regsets = 1;
  91
  92 /* Map gdb internal register number to ptrace ``address''.
  93    These ``addresses'' are normally defined in <asm/ptrace.h>.
  94
  95    ptrace does not provide a way to read (or set) MIPS_PS_REGNUM,
  96    and there's no point in reading or setting MIPS_ZERO_REGNUM.
  97    We also can not set BADVADDR, CAUSE, or FCRIR via ptrace().  */
  98
  99 static CORE_ADDR
 100 mips_linux_register_addr (struct gdbarch *gdbarch, int regno, int store)
 101 {
 102   CORE_ADDR regaddr;
 103
 104   if (regno < 0 || regno >= gdbarch_num_regs (gdbarch))
 105     error (_("Bogon register number %d."), regno);
 106
 107   if (regno > MIPS_ZERO_REGNUM && regno < MIPS_ZERO_REGNUM + 32)
 108     regaddr = regno;
 109   else if ((regno >= mips_regnum (gdbarch)->fp0)
 110            && (regno < mips_regnum (gdbarch)->fp0 + 32))
 111     regaddr = FPR_BASE + (regno - mips_regnum (gdbarch)->fp0);
 112   else if (regno == mips_regnum (gdbarch)->pc)
 113     regaddr = PC;
 114   else if (regno == mips_regnum (gdbarch)->cause)
 115     regaddr = store? (CORE_ADDR) -1 : CAUSE;
 116   else if (regno == mips_regnum (gdbarch)->badvaddr)
 117     regaddr = store? (CORE_ADDR) -1 : BADVADDR;
 118   else if (regno == mips_regnum (gdbarch)->lo)
 119     regaddr = MMLO;
 120   else if (regno == mips_regnum (gdbarch)->hi)
 121     regaddr = MMHI;
 122   else if (regno == mips_regnum (gdbarch)->fp_control_status)
 123     regaddr = FPC_CSR;
 124   else if (regno == mips_regnum (gdbarch)->fp_implementation_revision)
 125     regaddr = store? (CORE_ADDR) -1 : FPC_EIR;
 126   else if (mips_regnum (gdbarch)->dspacc != -1
 127            && regno >= mips_regnum (gdbarch)->dspacc
 128            && regno < mips_regnum (gdbarch)->dspacc + 6)
 129     regaddr = DSP_BASE + (regno - mips_regnum (gdbarch)->dspacc);
 130   else if (regno == mips_regnum (gdbarch)->dspctl)
 131     regaddr = DSP_CONTROL;
 132   else if (mips_linux_restart_reg_p (gdbarch) && regno == MIPS_RESTART_REGNUM)
 133     regaddr = 0;
 134   else
 135     regaddr = (CORE_ADDR) -1;
 136
 137   return regaddr;
 138 }
 139
 140 static CORE_ADDR
 141 mips64_linux_register_addr (struct gdbarch *gdbarch, int regno, int store)
 142 {
 143   CORE_ADDR regaddr;
 144
 145   if (regno < 0 || regno >= gdbarch_num_regs (gdbarch))
 146     error (_("Bogon register number %d."), regno);
 147
 148   /* On n32 we can't access 64-bit registers via PTRACE_PEEKUSR
 149      or PTRACE_POKEUSR.  */
 150   if (register_size (gdbarch, regno) > sizeof (PTRACE_TYPE_RET))
 151     return (CORE_ADDR) -1;
 152
 153   if (regno > MIPS_ZERO_REGNUM && regno < MIPS_ZERO_REGNUM + 32)
 154     regaddr = regno;
 155   else if ((regno >= mips_regnum (gdbarch)->fp0)
 156            && (regno < mips_regnum (gdbarch)->fp0 + 32))
 157     regaddr = MIPS64_FPR_BASE + (regno - gdbarch_fp0_regnum (gdbarch));
 158   else if (regno == mips_regnum (gdbarch)->pc)
 159     regaddr = MIPS64_PC;
 160   else if (regno == mips_regnum (gdbarch)->cause)
 161     regaddr = store? (CORE_ADDR) -1 : MIPS64_CAUSE;
 162   else if (regno == mips_regnum (gdbarch)->badvaddr)
 163     regaddr = store? (CORE_ADDR) -1 : MIPS64_BADVADDR;
 164   else if (regno == mips_regnum (gdbarch)->lo)
 165     regaddr = MIPS64_MMLO;
 166   else if (regno == mips_regnum (gdbarch)->hi)
 167     regaddr = MIPS64_MMHI;
 168   else if (regno == mips_regnum (gdbarch)->fp_control_status)
 169     regaddr = MIPS64_FPC_CSR;
 170   else if (regno == mips_regnum (gdbarch)->fp_implementation_revision)
 171     regaddr = store? (CORE_ADDR) -1 : MIPS64_FPC_EIR;
 172   else if (mips_regnum (gdbarch)->dspacc != -1
 173            && regno >= mips_regnum (gdbarch)->dspacc
 174            && regno < mips_regnum (gdbarch)->dspacc + 6)
 175     regaddr = DSP_BASE + (regno - mips_regnum (gdbarch)->dspacc);
 176   else if (regno == mips_regnum (gdbarch)->dspctl)
 177     regaddr = DSP_CONTROL;
 178   else if (mips_linux_restart_reg_p (gdbarch) && regno == MIPS_RESTART_REGNUM)
 179     regaddr = 0;
 180   else
 181     regaddr = (CORE_ADDR) -1;
 182
 183   return regaddr;
 184 }
 185
 186 /* Fetch the thread-local storage pointer for libthread_db.  */
 187
 188 ps_err_e
 189 ps_get_thread_area (struct ps_prochandle *ph,
 190                     lwpid_t lwpid, int idx, void **base)
 191 {
 192   if (ptrace (PTRACE_GET_THREAD_AREA, lwpid, NULL, base) != 0)
 193     return PS_ERR;
 194
 195   /* IDX is the bias from the thread pointer to the beginning of the
 196      thread descriptor.  It has to be subtracted due to implementation
 197      quirks in libthread_db.  */
 198   *base = (void *) ((char *)*base - idx);
 199
 200   return PS_OK;
 201 }
 202
 203 /* Wrapper functions.  These are only used by libthread_db.  */
 204
 205 void
 206 supply_gregset (struct regcache *regcache, const gdb_gregset_t *gregsetp)
 207 {
 208   if (mips_isa_regsize (regcache->arch ()) == 4)
 209     mips_supply_gregset (regcache, (const mips_elf_gregset_t *) gregsetp);
 210   else
 211     mips64_supply_gregset (regcache, (const mips64_elf_gregset_t *) gregsetp);
 212 }
 213
 214 void
 215 fill_gregset (const struct regcache *regcache,
 216               gdb_gregset_t *gregsetp, int regno)
 217 {
 218   if (mips_isa_regsize (regcache->arch ()) == 4)
 219     mips_fill_gregset (regcache, (mips_elf_gregset_t *) gregsetp, regno);
 220   else
 221     mips64_fill_gregset (regcache, (mips64_elf_gregset_t *) gregsetp, regno);
 222 }
 223
 224 void
 225 supply_fpregset (struct regcache *regcache, const gdb_fpregset_t *fpregsetp)
 226 {
 227   mips64_supply_fpregset (regcache, (const mips64_elf_fpregset_t *) fpregsetp);
 228 }
 229
 230 void
 231 fill_fpregset (const struct regcache *regcache,
 232                gdb_fpregset_t *fpregsetp, int regno)
 233 {
 234   mips64_fill_fpregset (regcache, (mips64_elf_fpregset_t *) fpregsetp, regno);
 235 }
 236
 237
 238 /* Fetch REGNO (or all registers if REGNO == -1) from the target
 239    using PTRACE_GETREGS et al.  */
 240
 241 void
 242 mips_linux_nat_target::mips64_regsets_fetch_registers
 243   (struct regcache *regcache, int regno)
 244 {
 245   struct gdbarch *gdbarch = regcache->arch ();
 246   int is_fp, is_dsp;
 247   int have_dsp;
 248   int regi;
 249   int tid;
 250
 251   if (regno >= mips_regnum (gdbarch)->fp0
 252       && regno <= mips_regnum (gdbarch)->fp0 + 32)
 253     is_fp = 1;
 254   else if (regno == mips_regnum (gdbarch)->fp_control_status)
 255     is_fp = 1;
 256   else if (regno == mips_regnum (gdbarch)->fp_implementation_revision)
 257     is_fp = 1;
 258   else
 259     is_fp = 0;
 260
 261   /* DSP registers are optional and not a part of any set.  */
 262   have_dsp = mips_regnum (gdbarch)->dspctl != -1;
 263   if (!have_dsp)
 264     is_dsp = 0;
 265   else if (regno >= mips_regnum (gdbarch)->dspacc
 266       && regno < mips_regnum (gdbarch)->dspacc + 6)
 267     is_dsp = 1;
 268   else if (regno == mips_regnum (gdbarch)->dspctl)
 269     is_dsp = 1;
 270   else
 271     is_dsp = 0;
 272
 273   tid = get_ptrace_pid (regcache->ptid ());
 274
 275   if (regno == -1 || (!is_fp && !is_dsp))
 276     {
 277       mips64_elf_gregset_t regs;
 278
 279       if (ptrace (PTRACE_GETREGS, tid, 0L, (PTRACE_TYPE_ARG3) &regs) == -1)
 280         {
 281           if (errno == EIO)
 282             {
 283               have_ptrace_regsets = 0;
 284               return;
 285             }
 286           perror_with_name (_("Couldn't get registers"));
 287         }
 288
 289       mips64_supply_gregset (regcache,
 290                              (const mips64_elf_gregset_t *) &regs);
 291     }
 292
 293   if (regno == -1 || is_fp)
 294     {
 295       mips64_elf_fpregset_t fp_regs;
 296
 297       if (ptrace (PTRACE_GETFPREGS, tid, 0L,
 298                   (PTRACE_TYPE_ARG3) &fp_regs) == -1)
 299         {
 300           if (errno == EIO)
 301             {
 302               have_ptrace_regsets = 0;
 303               return;
 304             }
 305           perror_with_name (_("Couldn't get FP registers"));
 306         }
 307
 308       mips64_supply_fpregset (regcache,
 309                               (const mips64_elf_fpregset_t *) &fp_regs);
 310     }
 311
 312   if (is_dsp)
 313     linux_nat_trad_target::fetch_registers (regcache, regno);
 314   else if (regno == -1 && have_dsp)
 315     {
 316       for (regi = mips_regnum (gdbarch)->dspacc;
 317            regi < mips_regnum (gdbarch)->dspacc + 6;
 318            regi++)
 319         linux_nat_trad_target::fetch_registers (regcache, regi);
 320       linux_nat_trad_target::fetch_registers (regcache,
 321                                               mips_regnum (gdbarch)->dspctl);
 322     }
 323 }
 324
 325 /* Store REGNO (or all registers if REGNO == -1) to the target
 326    using PTRACE_SETREGS et al.  */
 327
 328 void
 329 mips_linux_nat_target::mips64_regsets_store_registers
 330   (struct regcache *regcache, int regno)
 331 {
 332   struct gdbarch *gdbarch = regcache->arch ();
 333   int is_fp, is_dsp;
 334   int have_dsp;
 335   int regi;
 336   int tid;
 337
 338   if (regno >= mips_regnum (gdbarch)->fp0
 339       && regno <= mips_regnum (gdbarch)->fp0 + 32)
 340     is_fp = 1;
 341   else if (regno == mips_regnum (gdbarch)->fp_control_status)
 342     is_fp = 1;
 343   else if (regno == mips_regnum (gdbarch)->fp_implementation_revision)
 344     is_fp = 1;
 345   else
 346     is_fp = 0;
 347
 348   /* DSP registers are optional and not a part of any set.  */
 349   have_dsp = mips_regnum (gdbarch)->dspctl != -1;
 350   if (!have_dsp)
 351     is_dsp = 0;
 352   else if (regno >= mips_regnum (gdbarch)->dspacc
 353       && regno < mips_regnum (gdbarch)->dspacc + 6)
 354     is_dsp = 1;
 355   else if (regno == mips_regnum (gdbarch)->dspctl)
 356     is_dsp = 1;
 357   else
 358     is_dsp = 0;
 359
 360   tid = get_ptrace_pid (regcache->ptid ());
 361
 362   if (regno == -1 || (!is_fp && !is_dsp))
 363     {
 364       mips64_elf_gregset_t regs;
 365
 366       if (ptrace (PTRACE_GETREGS, tid, 0L, (PTRACE_TYPE_ARG3) &regs) == -1)
 367         perror_with_name (_("Couldn't get registers"));
 368
 369       mips64_fill_gregset (regcache, &regs, regno);
 370
 371       if (ptrace (PTRACE_SETREGS, tid, 0L, (PTRACE_TYPE_ARG3) &regs) == -1)
 372         perror_with_name (_("Couldn't set registers"));
 373     }
 374
 375   if (regno == -1 || is_fp)
 376     {
 377       mips64_elf_fpregset_t fp_regs;
 378
 379       if (ptrace (PTRACE_GETFPREGS, tid, 0L,
 380                   (PTRACE_TYPE_ARG3) &fp_regs) == -1)
 381         perror_with_name (_("Couldn't get FP registers"));
 382
 383       mips64_fill_fpregset (regcache, &fp_regs, regno);
 384
 385       if (ptrace (PTRACE_SETFPREGS, tid, 0L,
 386                   (PTRACE_TYPE_ARG3) &fp_regs) == -1)
 387         perror_with_name (_("Couldn't set FP registers"));
 388     }
 389
 390   if (is_dsp)
 391     linux_nat_trad_target::store_registers (regcache, regno);
 392   else if (regno == -1 && have_dsp)
 393     {
 394       for (regi = mips_regnum (gdbarch)->dspacc;
 395            regi < mips_regnum (gdbarch)->dspacc + 6;
 396            regi++)
 397         linux_nat_trad_target::store_registers (regcache, regi);
 398       linux_nat_trad_target::store_registers (regcache,
 399                                               mips_regnum (gdbarch)->dspctl);
 400     }
 401 }
 402
 403 /* Fetch REGNO (or all registers if REGNO == -1) from the target
 404    using any working method.  */
 405
 406 void
 407 mips_linux_nat_target::fetch_registers (struct regcache *regcache, int regnum)
 408 {
 409   /* Unless we already know that PTRACE_GETREGS does not work, try it.  */
 410   if (have_ptrace_regsets)
 411     mips64_regsets_fetch_registers (regcache, regnum);
 412
 413   /* If we know, or just found out, that PTRACE_GETREGS does not work, fall
 414      back to PTRACE_PEEKUSER.  */
 415   if (!have_ptrace_regsets)
 416     {
 417       linux_nat_trad_target::fetch_registers (regcache, regnum);
 418
 419       /* Fill the inaccessible zero register with zero.  */
 420       if (regnum == MIPS_ZERO_REGNUM || regnum == -1)
 421         regcache->raw_supply_zeroed (MIPS_ZERO_REGNUM);
 422     }
 423 }
 424
 425 /* Store REGNO (or all registers if REGNO == -1) to the target
 426    using any working method.  */
 427
 428 void
 429 mips_linux_nat_target::store_registers (struct regcache *regcache, int regnum)
 430 {
 431   /* Unless we already know that PTRACE_GETREGS does not work, try it.  */
 432   if (have_ptrace_regsets)
 433     mips64_regsets_store_registers (regcache, regnum);
 434
 435   /* If we know, or just found out, that PTRACE_GETREGS does not work, fall
 436      back to PTRACE_PEEKUSER.  */
 437   if (!have_ptrace_regsets)
 438     linux_nat_trad_target::store_registers (regcache, regnum);
 439 }
 440
 441 /* Return the address in the core dump or inferior of register
 442    REGNO.  */
 443
 444 CORE_ADDR
 445 mips_linux_nat_target::register_u_offset (struct gdbarch *gdbarch,
 446                                           int regno, int store_p)
 447 {
 448   if (mips_abi_regsize (gdbarch) == 8)
 449     return mips64_linux_register_addr (gdbarch, regno, store_p);
 450   else
 451     return mips_linux_register_addr (gdbarch, regno, store_p);
 452 }
 453
 454 const struct target_desc *
 455 mips_linux_nat_target::read_description ()
 456 {
 457   static int have_dsp = -1;
 458
 459   if (have_dsp < 0)
 460     {
 461       int tid = get_ptrace_pid (inferior_ptid);
 462
 463       errno = 0;
 464       ptrace (PTRACE_PEEKUSER, tid, DSP_CONTROL, 0);
 465       switch (errno)
 466         {
 467         case 0:
 468           have_dsp = 1;
 469           break;
 470         case EIO:
 471           have_dsp = 0;
 472           break;
 473         default:
 474           perror_with_name (_("Couldn't check DSP support"));
 475           break;
 476         }
 477     }
 478
 479   /* Report that target registers are a size we know for sure
 480      that we can get from ptrace.  */
 481   if (_MIPS_SIM == _ABIO32)
 482     return have_dsp ? tdesc_mips_dsp_linux : tdesc_mips_linux;
 483   else
 484     return have_dsp ? tdesc_mips64_dsp_linux : tdesc_mips64_linux;
 485 }
 486
 487 /* -1 if the kernel and/or CPU do not support watch registers.
 488     1 if watch_readback is valid and we can read style, num_valid
 489       and the masks.
 490     0 if we need to read the watch_readback.  */
 491
 492 static int watch_readback_valid;
 493
 494 /* Cached watch register read values.  */
 495
 496 static struct pt_watch_regs watch_readback;
 497
 498 static struct mips_watchpoint *current_watches;
 499
 500 /*  The current set of watch register values for writing the
 501     registers.  */
 502
 503 static struct pt_watch_regs watch_mirror;
 504
 505 static void
 506 mips_show_dr (const char *func, CORE_ADDR addr,
 507               int len, enum target_hw_bp_type type)
 508 {
 509   int i;
 510
 511   puts_unfiltered (func);
 512   if (addr || len)
 513     printf_unfiltered (" (addr=%s, len=%d, type=%s)",
 514                        paddress (target_gdbarch (), addr), len,
 515                        type == hw_write ? "data-write"
 516                        : (type == hw_read ? "data-read"
 517                           : (type == hw_access ? "data-read/write"
 518                              : (type == hw_execute ? "instruction-execute"
 519                                 : "??unknown??"))));
 520   puts_unfiltered (":\n");
 521
 522   for (i = 0; i < MAX_DEBUG_REGISTER; i++)
 523     printf_unfiltered ("\tDR%d: lo=%s, hi=%s\n", i,
 524                        paddress (target_gdbarch (),
 525                                  mips_linux_watch_get_watchlo (&watch_mirror,
 526                                                                i)),
 527                        paddress (target_gdbarch (),
 528                                  mips_linux_watch_get_watchhi (&watch_mirror,
 529                                                                i)));
 530 }
 531
 532 /* Target to_can_use_hw_breakpoint implementation.  Return 1 if we can
 533    handle the specified watch type.  */
 534
 535 int
 536 mips_linux_nat_target::can_use_hw_breakpoint (enum bptype type,
 537                                               int cnt, int ot)
 538 {
 539   int i;
 540   uint32_t wanted_mask, irw_mask;
 541
 542   if (!mips_linux_read_watch_registers (inferior_ptid.lwp (),
 543                                         &watch_readback,
 544                                         &watch_readback_valid, 0))
 545     return 0;
 546
 547    switch (type)
 548     {
 549     case bp_hardware_watchpoint:
 550       wanted_mask = W_MASK;
 551       break;
 552     case bp_read_watchpoint:
 553       wanted_mask = R_MASK;
 554       break;
 555     case bp_access_watchpoint:
 556       wanted_mask = R_MASK | W_MASK;
 557       break;
 558     default:
 559       return 0;
 560     }
 561
 562   for (i = 0;
 563        i < mips_linux_watch_get_num_valid (&watch_readback) && cnt;
 564        i++)
 565     {
 566       irw_mask = mips_linux_watch_get_irw_mask (&watch_readback, i);
 567       if ((irw_mask & wanted_mask) == wanted_mask)
 568         cnt--;
 569     }
 570   return (cnt == 0) ? 1 : 0;
 571 }
 572
 573 /* Target to_stopped_by_watchpoint implementation.  Return 1 if
 574    stopped by watchpoint.  The watchhi R and W bits indicate the watch
 575    register triggered.  */
 576
 577 bool
 578 mips_linux_nat_target::stopped_by_watchpoint ()
 579 {
 580   int n;
 581   int num_valid;
 582
 583   if (!mips_linux_read_watch_registers (inferior_ptid.lwp (),
 584                                         &watch_readback,
 585                                         &watch_readback_valid, 1))
 586     return false;
 587
 588   num_valid = mips_linux_watch_get_num_valid (&watch_readback);
 589
 590   for (n = 0; n < MAX_DEBUG_REGISTER && n < num_valid; n++)
 591     if (mips_linux_watch_get_watchhi (&watch_readback, n) & (R_MASK | W_MASK))
 592       return true;
 593
 594   return false;
 595 }
 596
 597 /* Target to_stopped_data_address implementation.  Set the address
 598    where the watch triggered (if known).  Return 1 if the address was
 599    known.  */
 600
 601 bool
 602 mips_linux_nat_target::stopped_data_address (CORE_ADDR *paddr)
 603 {
 604   /* On mips we don't know the low order 3 bits of the data address,
 605      so we must return false.  */
 606   return false;
 607 }
 608
 609 /* Target to_region_ok_for_hw_watchpoint implementation.  Return 1 if
 610    the specified region can be covered by the watch registers.  */
 611
 612 int
 613 mips_linux_nat_target::region_ok_for_hw_watchpoint (CORE_ADDR addr, int len)
 614 {
 615   struct pt_watch_regs dummy_regs;
 616   int i;
 617
 618   if (!mips_linux_read_watch_registers (inferior_ptid.lwp (),
 619                                         &watch_readback,
 620                                         &watch_readback_valid, 0))
 621     return 0;
 622
 623   dummy_regs = watch_readback;
 624   /* Clear them out.  */
 625   for (i = 0; i < mips_linux_watch_get_num_valid (&dummy_regs); i++)
 626     mips_linux_watch_set_watchlo (&dummy_regs, i, 0);
 627   return mips_linux_watch_try_one_watch (&dummy_regs, addr, len, 0);
 628 }
 629
 630 /* Write the mirrored watch register values for each thread.  */
 631
 632 static int
 633 write_watchpoint_regs (void)
 634 {
 635   struct lwp_info *lp;
 636   int tid;
 637
 638   ALL_LWPS (lp)
 639     {
 640       tid = lp->ptid.lwp ();
 641       if (ptrace (PTRACE_SET_WATCH_REGS, tid, &watch_mirror, NULL) == -1)
 642         perror_with_name (_("Couldn't write debug register"));
 643     }
 644   return 0;
 645 }
 646
 647 /* linux_nat_target::low_new_thread implementation.  Write the
 648    mirrored watch register values for the new thread.  */
 649
 650 void
 651 mips_linux_nat_target::low_new_thread (struct lwp_info *lp)
 652 {
 653   long tid = lp->ptid.lwp ();
 654
 655   if (!mips_linux_read_watch_registers (tid,
 656                                         &watch_readback,
 657                                         &watch_readback_valid, 0))
 658     return;
 659
 660   if (ptrace (PTRACE_SET_WATCH_REGS, tid, &watch_mirror, NULL) == -1)
 661     perror_with_name (_("Couldn't write debug register"));
 662 }
 663
 664 /* Target to_insert_watchpoint implementation.  Try to insert a new
 665    watch.  Return zero on success.  */
 666
 667 int
 668 mips_linux_nat_target::insert_watchpoint (CORE_ADDR addr, int len,
 669                                           enum target_hw_bp_type type,
 670                                           struct expression *cond)
 671 {
 672   struct pt_watch_regs regs;
 673   struct mips_watchpoint *new_watch;
 674   struct mips_watchpoint **pw;
 675
 676   int retval;
 677
 678   if (!mips_linux_read_watch_registers (inferior_ptid.lwp (),
 679                                         &watch_readback,
 680                                         &watch_readback_valid, 0))
 681     return -1;
 682
 683   if (len <= 0)
 684     return -1;
 685
 686   regs = watch_readback;
 687   /* Add the current watches.  */
 688   mips_linux_watch_populate_regs (current_watches, &regs);
 689
 690   /* Now try to add the new watch.  */
 691   if (!mips_linux_watch_try_one_watch (&regs, addr, len,
 692                                        mips_linux_watch_type_to_irw (type)))
 693     return -1;
 694
 695   /* It fit.  Stick it on the end of the list.  */
 696   new_watch = XNEW (struct mips_watchpoint);
 697   new_watch->addr = addr;
 698   new_watch->len = len;
 699   new_watch->type = type;
 700   new_watch->next = NULL;
 701
 702   pw = &current_watches;
 703   while (*pw != NULL)
 704     pw = &(*pw)->next;
 705   *pw = new_watch;
 706
 707   watch_mirror = regs;
 708   retval = write_watchpoint_regs ();
 709
 710   if (show_debug_regs)
 711     mips_show_dr ("insert_watchpoint", addr, len, type);
 712
 713   return retval;
 714 }
 715
 716 /* Target to_remove_watchpoint implementation.  Try to remove a watch.
 717    Return zero on success.  */
 718
 719 int
 720 mips_linux_nat_target::remove_watchpoint (CORE_ADDR addr, int len,
 721                                           enum target_hw_bp_type type,
 722                                           struct expression *cond)
 723 {
 724   int retval;
 725   int deleted_one;
 726
 727   struct mips_watchpoint **pw;
 728   struct mips_watchpoint *w;
 729
 730   /* Search for a known watch that matches.  Then unlink and free
 731      it.  */
 732   deleted_one = 0;
 733   pw = &current_watches;
 734   while ((w = *pw))
 735     {
 736       if (w->addr == addr && w->len == len && w->type == type)
 737         {
 738           *pw = w->next;
 739           xfree (w);
 740           deleted_one = 1;
 741           break;
 742         }
 743       pw = &(w->next);
 744     }
 745
 746   if (!deleted_one)
 747     return -1;  /* We don't know about it, fail doing nothing.  */
 748
 749   /* At this point watch_readback is known to be valid because we
 750      could not have added the watch without reading it.  */
 751   gdb_assert (watch_readback_valid == 1);
 752
 753   watch_mirror = watch_readback;
 754   mips_linux_watch_populate_regs (current_watches, &watch_mirror);
 755
 756   retval = write_watchpoint_regs ();
 757
 758   if (show_debug_regs)
 759     mips_show_dr ("remove_watchpoint", addr, len, type);
 760
 761   return retval;
 762 }
 763
 764 /* Target to_close implementation.  Free any watches and call the
 765    super implementation.  */
 766
 767 void
 768 mips_linux_nat_target::close ()
 769 {
 770   struct mips_watchpoint *w;
 771   struct mips_watchpoint *nw;
 772
 773   /* Clean out the current_watches list.  */
 774   w = current_watches;
 775   while (w)
 776     {
 777       nw = w->next;
 778       xfree (w);
 779       w = nw;
 780     }
 781   current_watches = NULL;
 782
 783   linux_nat_trad_target::close ();
 784 }
 785
 786 void
 787 _initialize_mips_linux_nat (void)
 788 {
 789   add_setshow_boolean_cmd ("show-debug-regs", class_maintenance,
 790                            &show_debug_regs, _("\
 791 Set whether to show variables that mirror the mips debug registers."), _("\
 792 Show whether to show variables that mirror the mips debug registers."), _("\
 793 Use \"on\" to enable, \"off\" to disable.\n\
 794 If enabled, the debug registers values are shown when GDB inserts\n\
 795 or removes a hardware breakpoint or watchpoint, and when the inferior\n\
 796 triggers a breakpoint or watchpoint."),
 797                            NULL,
 798                            NULL,
 799                            &maintenance_set_cmdlist,
 800                            &maintenance_show_cmdlist);
 801
 802   linux_target = &the_mips_linux_nat_target;
 803   add_inf_child_target (&the_mips_linux_nat_target);
 804 }