gdb/aarch64-linux-nat.c

   1 /* Native-dependent code for GNU/Linux AArch64.
   2
   3    Copyright (C) 2011-2017 Free Software Foundation, Inc.
   4    Contributed by ARM Ltd.
   5
   6    This file is part of GDB.
   7
   8    This program is free software; you can redistribute it and/or modify
   9    it under the terms of the GNU General Public License as published by
  10    the Free Software Foundation; either version 3 of the License, or
  11    (at your option) any later version.
  12
  13    This program is distributed in the hope that it will be useful,
  14    but WITHOUT ANY WARRANTY; without even the implied warranty of
  15    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16    GNU General Public License for more details.
  17
  18    You should have received a copy of the GNU General Public License
  19    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
  20
  21 #include "defs.h"
  22
  23 #include "inferior.h"
  24 #include "gdbcore.h"
  25 #include "regcache.h"
  26 #include "linux-nat.h"
  27 #include "target-descriptions.h"
  28 #include "auxv.h"
  29 #include "gdbcmd.h"
  30 #include "aarch64-tdep.h"
  31 #include "aarch64-linux-tdep.h"
  32 #include "aarch32-linux-nat.h"
  33 #include "nat/aarch64-linux.h"
  34 #include "nat/aarch64-linux-hw-point.h"
  35
  36 #include "elf/external.h"
  37 #include "elf/common.h"
  38
  39 #include "nat/gdb_ptrace.h"
  40 #include <sys/utsname.h>
  41 #include <asm/ptrace.h>
  42
  43 #include "gregset.h"
  44
  45 /* Defines ps_err_e, struct ps_prochandle.  */
  46 #include "gdb_proc_service.h"
  47
  48 #ifndef TRAP_HWBKPT
  49 #define TRAP_HWBKPT 0x0004
  50 #endif
  51
  52 /* Per-process data.  We don't bind this to a per-inferior registry
  53    because of targets like x86 GNU/Linux that need to keep track of
  54    processes that aren't bound to any inferior (e.g., fork children,
  55    checkpoints).  */
  56
  57 struct aarch64_process_info
  58 {
  59   /* Linked list.  */
  60   struct aarch64_process_info *next;
  61
  62   /* The process identifier.  */
  63   pid_t pid;
  64
  65   /* Copy of aarch64 hardware debug registers.  */
  66   struct aarch64_debug_reg_state state;
  67 };
  68
  69 static struct aarch64_process_info *aarch64_process_list = NULL;
  70
  71 /* Find process data for process PID.  */
  72
  73 static struct aarch64_process_info *
  74 aarch64_find_process_pid (pid_t pid)
  75 {
  76   struct aarch64_process_info *proc;
  77
  78   for (proc = aarch64_process_list; proc; proc = proc->next)
  79     if (proc->pid == pid)
  80       return proc;
  81
  82   return NULL;
  83 }
  84
  85 /* Add process data for process PID.  Returns newly allocated info
  86    object.  */
  87
  88 static struct aarch64_process_info *
  89 aarch64_add_process (pid_t pid)
  90 {
  91   struct aarch64_process_info *proc;
  92
  93   proc = XCNEW (struct aarch64_process_info);
  94   proc->pid = pid;
  95
  96   proc->next = aarch64_process_list;
  97   aarch64_process_list = proc;
  98
  99   return proc;
 100 }
 101
 102 /* Get data specific info for process PID, creating it if necessary.
 103    Never returns NULL.  */
 104
 105 static struct aarch64_process_info *
 106 aarch64_process_info_get (pid_t pid)
 107 {
 108   struct aarch64_process_info *proc;
 109
 110   proc = aarch64_find_process_pid (pid);
 111   if (proc == NULL)
 112     proc = aarch64_add_process (pid);
 113
 114   return proc;
 115 }
 116
 117 /* Called whenever GDB is no longer debugging process PID.  It deletes
 118    data structures that keep track of debug register state.  */
 119
 120 static void
 121 aarch64_forget_process (pid_t pid)
 122 {
 123   struct aarch64_process_info *proc, **proc_link;
 124
 125   proc = aarch64_process_list;
 126   proc_link = &aarch64_process_list;
 127
 128   while (proc != NULL)
 129     {
 130       if (proc->pid == pid)
 131         {
 132           *proc_link = proc->next;
 133
 134           xfree (proc);
 135           return;
 136         }
 137
 138       proc_link = &proc->next;
 139       proc = *proc_link;
 140     }
 141 }
 142
 143 /* Get debug registers state for process PID.  */
 144
 145 struct aarch64_debug_reg_state *
 146 aarch64_get_debug_reg_state (pid_t pid)
 147 {
 148   return &aarch64_process_info_get (pid)->state;
 149 }
 150
 151 /* Fill GDB's register array with the general-purpose register values
 152    from the current thread.  */
 153
 154 static void
 155 fetch_gregs_from_thread (struct regcache *regcache)
 156 {
 157   int ret, tid;
 158   struct gdbarch *gdbarch = get_regcache_arch (regcache);
 159   elf_gregset_t regs;
 160   struct iovec iovec;
 161
 162   /* Make sure REGS can hold all registers contents on both aarch64
 163      and arm.  */
 164   gdb_static_assert (sizeof (regs) >= 18 * 4);
 165
 166   tid = ptid_get_lwp (regcache_get_ptid (regcache));
 167
 168   iovec.iov_base = &regs;
 169   if (gdbarch_bfd_arch_info (gdbarch)->bits_per_word == 32)
 170     iovec.iov_len = 18 * 4;
 171   else
 172     iovec.iov_len = sizeof (regs);
 173
 174   ret = ptrace (PTRACE_GETREGSET, tid, NT_PRSTATUS, &iovec);
 175   if (ret < 0)
 176     perror_with_name (_("Unable to fetch general registers."));
 177
 178   if (gdbarch_bfd_arch_info (gdbarch)->bits_per_word == 32)
 179     aarch32_gp_regcache_supply (regcache, (uint32_t *) regs, 1);
 180   else
 181     {
 182       int regno;
 183
 184       for (regno = AARCH64_X0_REGNUM; regno <= AARCH64_CPSR_REGNUM; regno++)
 185         regcache_raw_supply (regcache, regno, &regs[regno - AARCH64_X0_REGNUM]);
 186     }
 187 }
 188
 189 /* Store to the current thread the valid general-purpose register
 190    values in the GDB's register array.  */
 191
 192 static void
 193 store_gregs_to_thread (const struct regcache *regcache)
 194 {
 195   int ret, tid;
 196   elf_gregset_t regs;
 197   struct iovec iovec;
 198   struct gdbarch *gdbarch = get_regcache_arch (regcache);
 199
 200   /* Make sure REGS can hold all registers contents on both aarch64
 201      and arm.  */
 202   gdb_static_assert (sizeof (regs) >= 18 * 4);
 203   tid = ptid_get_lwp (regcache_get_ptid (regcache));
 204
 205   iovec.iov_base = &regs;
 206   if (gdbarch_bfd_arch_info (gdbarch)->bits_per_word == 32)
 207     iovec.iov_len = 18 * 4;
 208   else
 209     iovec.iov_len = sizeof (regs);
 210
 211   ret = ptrace (PTRACE_GETREGSET, tid, NT_PRSTATUS, &iovec);
 212   if (ret < 0)
 213     perror_with_name (_("Unable to fetch general registers."));
 214
 215   if (gdbarch_bfd_arch_info (gdbarch)->bits_per_word == 32)
 216     aarch32_gp_regcache_collect (regcache, (uint32_t *) regs, 1);
 217   else
 218     {
 219       int regno;
 220
 221       for (regno = AARCH64_X0_REGNUM; regno <= AARCH64_CPSR_REGNUM; regno++)
 222         if (REG_VALID == regcache_register_status (regcache, regno))
 223           regcache_raw_collect (regcache, regno,
 224                                 &regs[regno - AARCH64_X0_REGNUM]);
 225     }
 226
 227   ret = ptrace (PTRACE_SETREGSET, tid, NT_PRSTATUS, &iovec);
 228   if (ret < 0)
 229     perror_with_name (_("Unable to store general registers."));
 230 }
 231
 232 /* Fill GDB's register array with the fp/simd register values
 233    from the current thread.  */
 234
 235 static void
 236 fetch_fpregs_from_thread (struct regcache *regcache)
 237 {
 238   int ret, tid;
 239   elf_fpregset_t regs;
 240   struct iovec iovec;
 241   struct gdbarch *gdbarch = get_regcache_arch (regcache);
 242
 243   /* Make sure REGS can hold all VFP registers contents on both aarch64
 244      and arm.  */
 245   gdb_static_assert (sizeof regs >= VFP_REGS_SIZE);
 246
 247   tid = ptid_get_lwp (regcache_get_ptid (regcache));
 248
 249   iovec.iov_base = &regs;
 250
 251   if (gdbarch_bfd_arch_info (gdbarch)->bits_per_word == 32)
 252     {
 253       iovec.iov_len = VFP_REGS_SIZE;
 254
 255       ret = ptrace (PTRACE_GETREGSET, tid, NT_ARM_VFP, &iovec);
 256       if (ret < 0)
 257         perror_with_name (_("Unable to fetch VFP registers."));
 258
 259       aarch32_vfp_regcache_supply (regcache, (gdb_byte *) &regs, 32);
 260     }
 261   else
 262     {
 263       int regno;
 264
 265       iovec.iov_len = sizeof (regs);
 266
 267       ret = ptrace (PTRACE_GETREGSET, tid, NT_FPREGSET, &iovec);
 268       if (ret < 0)
 269         perror_with_name (_("Unable to fetch vFP/SIMD registers."));
 270
 271       for (regno = AARCH64_V0_REGNUM; regno <= AARCH64_V31_REGNUM; regno++)
 272         regcache_raw_supply (regcache, regno,
 273                              &regs.vregs[regno - AARCH64_V0_REGNUM]);
 274
 275       regcache_raw_supply (regcache, AARCH64_FPSR_REGNUM, &regs.fpsr);
 276       regcache_raw_supply (regcache, AARCH64_FPCR_REGNUM, &regs.fpcr);
 277     }
 278 }
 279
 280 /* Store to the current thread the valid fp/simd register
 281    values in the GDB's register array.  */
 282
 283 static void
 284 store_fpregs_to_thread (const struct regcache *regcache)
 285 {
 286   int ret, tid;
 287   elf_fpregset_t regs;
 288   struct iovec iovec;
 289   struct gdbarch *gdbarch = get_regcache_arch (regcache);
 290
 291   /* Make sure REGS can hold all VFP registers contents on both aarch64
 292      and arm.  */
 293   gdb_static_assert (sizeof regs >= VFP_REGS_SIZE);
 294   tid = ptid_get_lwp (regcache_get_ptid (regcache));
 295
 296   iovec.iov_base = &regs;
 297
 298   if (gdbarch_bfd_arch_info (gdbarch)->bits_per_word == 32)
 299     {
 300       iovec.iov_len = VFP_REGS_SIZE;
 301
 302       ret = ptrace (PTRACE_GETREGSET, tid, NT_ARM_VFP, &iovec);
 303       if (ret < 0)
 304         perror_with_name (_("Unable to fetch VFP registers."));
 305
 306       aarch32_vfp_regcache_collect (regcache, (gdb_byte *) &regs, 32);
 307     }
 308   else
 309     {
 310       int regno;
 311
 312       iovec.iov_len = sizeof (regs);
 313
 314       ret = ptrace (PTRACE_GETREGSET, tid, NT_FPREGSET, &iovec);
 315       if (ret < 0)
 316         perror_with_name (_("Unable to fetch FP/SIMD registers."));
 317
 318       for (regno = AARCH64_V0_REGNUM; regno <= AARCH64_V31_REGNUM; regno++)
 319         if (REG_VALID == regcache_register_status (regcache, regno))
 320           regcache_raw_collect (regcache, regno,
 321                                 (char *) &regs.vregs[regno - AARCH64_V0_REGNUM]);
 322
 323       if (REG_VALID == regcache_register_status (regcache, AARCH64_FPSR_REGNUM))
 324         regcache_raw_collect (regcache, AARCH64_FPSR_REGNUM,
 325                               (char *) &regs.fpsr);
 326       if (REG_VALID == regcache_register_status (regcache, AARCH64_FPCR_REGNUM))
 327         regcache_raw_collect (regcache, AARCH64_FPCR_REGNUM,
 328                               (char *) &regs.fpcr);
 329     }
 330
 331   if (gdbarch_bfd_arch_info (gdbarch)->bits_per_word == 32)
 332     {
 333       ret = ptrace (PTRACE_SETREGSET, tid, NT_ARM_VFP, &iovec);
 334       if (ret < 0)
 335         perror_with_name (_("Unable to store VFP registers."));
 336     }
 337   else
 338     {
 339       ret = ptrace (PTRACE_SETREGSET, tid, NT_FPREGSET, &iovec);
 340       if (ret < 0)
 341         perror_with_name (_("Unable to store FP/SIMD registers."));
 342     }
 343 }
 344
 345 /* Implement the "to_fetch_register" target_ops method.  */
 346
 347 static void
 348 aarch64_linux_fetch_inferior_registers (struct target_ops *ops,
 349                                         struct regcache *regcache,
 350                                         int regno)
 351 {
 352   if (regno == -1)
 353     {
 354       fetch_gregs_from_thread (regcache);
 355       fetch_fpregs_from_thread (regcache);
 356     }
 357   else if (regno < AARCH64_V0_REGNUM)
 358     fetch_gregs_from_thread (regcache);
 359   else
 360     fetch_fpregs_from_thread (regcache);
 361 }
 362
 363 /* Implement the "to_store_register" target_ops method.  */
 364
 365 static void
 366 aarch64_linux_store_inferior_registers (struct target_ops *ops,
 367                                         struct regcache *regcache,
 368                                         int regno)
 369 {
 370   if (regno == -1)
 371     {
 372       store_gregs_to_thread (regcache);
 373       store_fpregs_to_thread (regcache);
 374     }
 375   else if (regno < AARCH64_V0_REGNUM)
 376     store_gregs_to_thread (regcache);
 377   else
 378     store_fpregs_to_thread (regcache);
 379 }
 380
 381 /* Fill register REGNO (if it is a general-purpose register) in
 382    *GREGSETPS with the value in GDB's register array.  If REGNO is -1,
 383    do this for all registers.  */
 384
 385 void
 386 fill_gregset (const struct regcache *regcache,
 387               gdb_gregset_t *gregsetp, int regno)
 388 {
 389   regcache_collect_regset (&aarch64_linux_gregset, regcache,
 390                            regno, (gdb_byte *) gregsetp,
 391                            AARCH64_LINUX_SIZEOF_GREGSET);
 392 }
 393
 394 /* Fill GDB's register array with the general-purpose register values
 395    in *GREGSETP.  */
 396
 397 void
 398 supply_gregset (struct regcache *regcache, const gdb_gregset_t *gregsetp)
 399 {
 400   regcache_supply_regset (&aarch64_linux_gregset, regcache, -1,
 401                           (const gdb_byte *) gregsetp,
 402                           AARCH64_LINUX_SIZEOF_GREGSET);
 403 }
 404
 405 /* Fill register REGNO (if it is a floating-point register) in
 406    *FPREGSETP with the value in GDB's register array.  If REGNO is -1,
 407    do this for all registers.  */
 408
 409 void
 410 fill_fpregset (const struct regcache *regcache,
 411                gdb_fpregset_t *fpregsetp, int regno)
 412 {
 413   regcache_collect_regset (&aarch64_linux_fpregset, regcache,
 414                            regno, (gdb_byte *) fpregsetp,
 415                            AARCH64_LINUX_SIZEOF_FPREGSET);
 416 }
 417
 418 /* Fill GDB's register array with the floating-point register values
 419    in *FPREGSETP.  */
 420
 421 void
 422 supply_fpregset (struct regcache *regcache, const gdb_fpregset_t *fpregsetp)
 423 {
 424   regcache_supply_regset (&aarch64_linux_fpregset, regcache, -1,
 425                           (const gdb_byte *) fpregsetp,
 426                           AARCH64_LINUX_SIZEOF_FPREGSET);
 427 }
 428
 429 /* linux_nat_new_fork hook.   */
 430
 431 static void
 432 aarch64_linux_new_fork (struct lwp_info *parent, pid_t child_pid)
 433 {
 434   pid_t parent_pid;
 435   struct aarch64_debug_reg_state *parent_state;
 436   struct aarch64_debug_reg_state *child_state;
 437
 438   /* NULL means no watchpoint has ever been set in the parent.  In
 439      that case, there's nothing to do.  */
 440   if (parent->arch_private == NULL)
 441     return;
 442
 443   /* GDB core assumes the child inherits the watchpoints/hw
 444      breakpoints of the parent, and will remove them all from the
 445      forked off process.  Copy the debug registers mirrors into the
 446      new process so that all breakpoints and watchpoints can be
 447      removed together.  */
 448
 449   parent_pid = ptid_get_pid (parent->ptid);
 450   parent_state = aarch64_get_debug_reg_state (parent_pid);
 451   child_state = aarch64_get_debug_reg_state (child_pid);
 452   *child_state = *parent_state;
 453 }
 454 \f
 455
 456 /* Called by libthread_db.  Returns a pointer to the thread local
 457    storage (or its descriptor).  */
 458
 459 ps_err_e
 460 ps_get_thread_area (struct ps_prochandle *ph,
 461                     lwpid_t lwpid, int idx, void **base)
 462 {
 463   int is_64bit_p
 464     = (gdbarch_bfd_arch_info (target_gdbarch ())->bits_per_word == 64);
 465
 466   return aarch64_ps_get_thread_area (ph, lwpid, idx, base, is_64bit_p);
 467 }
 468 \f
 469
 470 static void (*super_post_startup_inferior) (struct target_ops *self,
 471                                             ptid_t ptid);
 472
 473 /* Implement the "to_post_startup_inferior" target_ops method.  */
 474
 475 static void
 476 aarch64_linux_child_post_startup_inferior (struct target_ops *self,
 477                                            ptid_t ptid)
 478 {
 479   aarch64_forget_process (ptid_get_pid (ptid));
 480   aarch64_linux_get_debug_reg_capacity (ptid_get_pid (ptid));
 481   super_post_startup_inferior (self, ptid);
 482 }
 483
 484 extern struct target_desc *tdesc_arm_with_neon;
 485
 486 /* Implement the "to_read_description" target_ops method.  */
 487
 488 static const struct target_desc *
 489 aarch64_linux_read_description (struct target_ops *ops)
 490 {
 491   int ret, tid;
 492   gdb_byte regbuf[VFP_REGS_SIZE];
 493   struct iovec iovec;
 494
 495   tid = ptid_get_lwp (inferior_ptid);
 496
 497   iovec.iov_base = regbuf;
 498   iovec.iov_len = VFP_REGS_SIZE;
 499
 500   ret = ptrace (PTRACE_GETREGSET, tid, NT_ARM_VFP, &iovec);
 501   if (ret == 0)
 502     return tdesc_arm_with_neon;
 503   else
 504     return tdesc_aarch64;
 505 }
 506
 507 /* Convert a native/host siginfo object, into/from the siginfo in the
 508    layout of the inferiors' architecture.  Returns true if any
 509    conversion was done; false otherwise.  If DIRECTION is 1, then copy
 510    from INF to NATIVE.  If DIRECTION is 0, copy from NATIVE to
 511    INF.  */
 512
 513 static int
 514 aarch64_linux_siginfo_fixup (siginfo_t *native, gdb_byte *inf, int direction)
 515 {
 516   struct gdbarch *gdbarch = get_frame_arch (get_current_frame ());
 517
 518   /* Is the inferior 32-bit?  If so, then do fixup the siginfo
 519      object.  */
 520   if (gdbarch_bfd_arch_info (gdbarch)->bits_per_word == 32)
 521     {
 522       if (direction == 0)
 523         aarch64_compat_siginfo_from_siginfo ((struct compat_siginfo *) inf,
 524                                              native);
 525       else
 526         aarch64_siginfo_from_compat_siginfo (native,
 527                                              (struct compat_siginfo *) inf);
 528
 529       return 1;
 530     }
 531
 532   return 0;
 533 }
 534
 535 /* Returns the number of hardware watchpoints of type TYPE that we can
 536    set.  Value is positive if we can set CNT watchpoints, zero if
 537    setting watchpoints of type TYPE is not supported, and negative if
 538    CNT is more than the maximum number of watchpoints of type TYPE
 539    that we can support.  TYPE is one of bp_hardware_watchpoint,
 540    bp_read_watchpoint, bp_write_watchpoint, or bp_hardware_breakpoint.
 541    CNT is the number of such watchpoints used so far (including this
 542    one).  OTHERTYPE is non-zero if other types of watchpoints are
 543    currently enabled.  */
 544
 545 static int
 546 aarch64_linux_can_use_hw_breakpoint (struct target_ops *self,
 547                                      enum bptype type,
 548                                      int cnt, int othertype)
 549 {
 550   if (type == bp_hardware_watchpoint || type == bp_read_watchpoint
 551       || type == bp_access_watchpoint || type == bp_watchpoint)
 552     {
 553       if (aarch64_num_wp_regs == 0)
 554         return 0;
 555     }
 556   else if (type == bp_hardware_breakpoint)
 557     {
 558       if (aarch64_num_bp_regs == 0)
 559         return 0;
 560     }
 561   else
 562     gdb_assert_not_reached ("unexpected breakpoint type");
 563
 564   /* We always return 1 here because we don't have enough information
 565      about possible overlap of addresses that they want to watch.  As an
 566      extreme example, consider the case where all the watchpoints watch
 567      the same address and the same region length: then we can handle a
 568      virtually unlimited number of watchpoints, due to debug register
 569      sharing implemented via reference counts.  */
 570   return 1;
 571 }
 572
 573 /* Insert a hardware-assisted breakpoint at BP_TGT->reqstd_address.
 574    Return 0 on success, -1 on failure.  */
 575
 576 static int
 577 aarch64_linux_insert_hw_breakpoint (struct target_ops *self,
 578                                     struct gdbarch *gdbarch,
 579                                     struct bp_target_info *bp_tgt)
 580 {
 581   int ret;
 582   CORE_ADDR addr = bp_tgt->placed_address = bp_tgt->reqstd_address;
 583   int len;
 584   const enum target_hw_bp_type type = hw_execute;
 585   struct aarch64_debug_reg_state *state
 586     = aarch64_get_debug_reg_state (ptid_get_pid (inferior_ptid));
 587
 588   gdbarch_breakpoint_from_pc (gdbarch, &addr, &len);
 589
 590   if (show_debug_regs)
 591     fprintf_unfiltered
 592       (gdb_stdlog,
 593        "insert_hw_breakpoint on entry (addr=0x%08lx, len=%d))\n",
 594        (unsigned long) addr, len);
 595
 596   ret = aarch64_handle_breakpoint (type, addr, len, 1 /* is_insert */, state);
 597
 598   if (show_debug_regs)
 599     {
 600       aarch64_show_debug_reg_state (state,
 601                                     "insert_hw_breakpoint", addr, len, type);
 602     }
 603
 604   return ret;
 605 }
 606
 607 /* Remove a hardware-assisted breakpoint at BP_TGT->placed_address.
 608    Return 0 on success, -1 on failure.  */
 609
 610 static int
 611 aarch64_linux_remove_hw_breakpoint (struct target_ops *self,
 612                                     struct gdbarch *gdbarch,
 613                                     struct bp_target_info *bp_tgt)
 614 {
 615   int ret;
 616   CORE_ADDR addr = bp_tgt->placed_address;
 617   int len = 4;
 618   const enum target_hw_bp_type type = hw_execute;
 619   struct aarch64_debug_reg_state *state
 620     = aarch64_get_debug_reg_state (ptid_get_pid (inferior_ptid));
 621
 622   gdbarch_breakpoint_from_pc (gdbarch, &addr, &len);
 623
 624   if (show_debug_regs)
 625     fprintf_unfiltered
 626       (gdb_stdlog, "remove_hw_breakpoint on entry (addr=0x%08lx, len=%d))\n",
 627        (unsigned long) addr, len);
 628
 629   ret = aarch64_handle_breakpoint (type, addr, len, 0 /* is_insert */, state);
 630
 631   if (show_debug_regs)
 632     {
 633       aarch64_show_debug_reg_state (state,
 634                                     "remove_hw_watchpoint", addr, len, type);
 635     }
 636
 637   return ret;
 638 }
 639
 640 /* Implement the "to_insert_watchpoint" target_ops method.
 641
 642    Insert a watchpoint to watch a memory region which starts at
 643    address ADDR and whose length is LEN bytes.  Watch memory accesses
 644    of the type TYPE.  Return 0 on success, -1 on failure.  */
 645
 646 static int
 647 aarch64_linux_insert_watchpoint (struct target_ops *self,
 648                                  CORE_ADDR addr, int len,
 649                                  enum target_hw_bp_type type,
 650                                  struct expression *cond)
 651 {
 652   int ret;
 653   struct aarch64_debug_reg_state *state
 654     = aarch64_get_debug_reg_state (ptid_get_pid (inferior_ptid));
 655
 656   if (show_debug_regs)
 657     fprintf_unfiltered (gdb_stdlog,
 658                         "insert_watchpoint on entry (addr=0x%08lx, len=%d)\n",
 659                         (unsigned long) addr, len);
 660
 661   gdb_assert (type != hw_execute);
 662
 663   ret = aarch64_handle_watchpoint (type, addr, len, 1 /* is_insert */, state);
 664
 665   if (show_debug_regs)
 666     {
 667       aarch64_show_debug_reg_state (state,
 668                                     "insert_watchpoint", addr, len, type);
 669     }
 670
 671   return ret;
 672 }
 673
 674 /* Implement the "to_remove_watchpoint" target_ops method.
 675    Remove a watchpoint that watched the memory region which starts at
 676    address ADDR, whose length is LEN bytes, and for accesses of the
 677    type TYPE.  Return 0 on success, -1 on failure.  */
 678
 679 static int
 680 aarch64_linux_remove_watchpoint (struct target_ops *self,
 681                                  CORE_ADDR addr, int len,
 682                                  enum target_hw_bp_type type,
 683                                  struct expression *cond)
 684 {
 685   int ret;
 686   struct aarch64_debug_reg_state *state
 687     = aarch64_get_debug_reg_state (ptid_get_pid (inferior_ptid));
 688
 689   if (show_debug_regs)
 690     fprintf_unfiltered (gdb_stdlog,
 691                         "remove_watchpoint on entry (addr=0x%08lx, len=%d)\n",
 692                         (unsigned long) addr, len);
 693
 694   gdb_assert (type != hw_execute);
 695
 696   ret = aarch64_handle_watchpoint (type, addr, len, 0 /* is_insert */, state);
 697
 698   if (show_debug_regs)
 699     {
 700       aarch64_show_debug_reg_state (state,
 701                                     "remove_watchpoint", addr, len, type);
 702     }
 703
 704   return ret;
 705 }
 706
 707 /* Implement the "to_region_ok_for_hw_watchpoint" target_ops method.  */
 708
 709 static int
 710 aarch64_linux_region_ok_for_hw_watchpoint (struct target_ops *self,
 711                                            CORE_ADDR addr, int len)
 712 {
 713   return aarch64_linux_region_ok_for_watchpoint (addr, len);
 714 }
 715
 716 /* Implement the "to_stopped_data_address" target_ops method.  */
 717
 718 static int
 719 aarch64_linux_stopped_data_address (struct target_ops *target,
 720                                     CORE_ADDR *addr_p)
 721 {
 722   siginfo_t siginfo;
 723   int i, tid;
 724   struct aarch64_debug_reg_state *state;
 725
 726   if (!linux_nat_get_siginfo (inferior_ptid, &siginfo))
 727     return 0;
 728
 729   /* This must be a hardware breakpoint.  */
 730   if (siginfo.si_signo != SIGTRAP
 731       || (siginfo.si_code & 0xffff) != TRAP_HWBKPT)
 732     return 0;
 733
 734   /* Check if the address matches any watched address.  */
 735   state = aarch64_get_debug_reg_state (ptid_get_pid (inferior_ptid));
 736   for (i = aarch64_num_wp_regs - 1; i >= 0; --i)
 737     {
 738       const unsigned int len = aarch64_watchpoint_length (state->dr_ctrl_wp[i]);
 739       const CORE_ADDR addr_trap = (CORE_ADDR) siginfo.si_addr;
 740       const CORE_ADDR addr_watch = state->dr_addr_wp[i];
 741
 742       if (state->dr_ref_count_wp[i]
 743           && DR_CONTROL_ENABLED (state->dr_ctrl_wp[i])
 744           && addr_trap >= addr_watch
 745           && addr_trap < addr_watch + len)
 746         {
 747           *addr_p = addr_trap;
 748           return 1;
 749         }
 750     }
 751
 752   return 0;
 753 }
 754
 755 /* Implement the "to_stopped_by_watchpoint" target_ops method.  */
 756
 757 static int
 758 aarch64_linux_stopped_by_watchpoint (struct target_ops *ops)
 759 {
 760   CORE_ADDR addr;
 761
 762   return aarch64_linux_stopped_data_address (ops, &addr);
 763 }
 764
 765 /* Implement the "to_watchpoint_addr_within_range" target_ops method.  */
 766
 767 static int
 768 aarch64_linux_watchpoint_addr_within_range (struct target_ops *target,
 769                                             CORE_ADDR addr,
 770                                             CORE_ADDR start, int length)
 771 {
 772   return start <= addr && start + length - 1 >= addr;
 773 }
 774
 775 /* Implement the "to_can_do_single_step" target_ops method.  */
 776
 777 static int
 778 aarch64_linux_can_do_single_step (struct target_ops *target)
 779 {
 780   return 1;
 781 }
 782
 783 /* Define AArch64 maintenance commands.  */
 784
 785 static void
 786 add_show_debug_regs_command (void)
 787 {
 788   /* A maintenance command to enable printing the internal DRi mirror
 789      variables.  */
 790   add_setshow_boolean_cmd ("show-debug-regs", class_maintenance,
 791                            &show_debug_regs, _("\
 792 Set whether to show variables that mirror the AArch64 debug registers."), _("\
 793 Show whether to show variables that mirror the AArch64 debug registers."), _("\
 794 Use \"on\" to enable, \"off\" to disable.\n\
 795 If enabled, the debug registers values are shown when GDB inserts\n\
 796 or removes a hardware breakpoint or watchpoint, and when the inferior\n\
 797 triggers a breakpoint or watchpoint."),
 798                            NULL,
 799                            NULL,
 800                            &maintenance_set_cmdlist,
 801                            &maintenance_show_cmdlist);
 802 }
 803
 804 void
 805 _initialize_aarch64_linux_nat (void)
 806 {
 807   struct target_ops *t;
 808
 809   /* Fill in the generic GNU/Linux methods.  */
 810   t = linux_target ();
 811
 812   add_show_debug_regs_command ();
 813
 814   /* Add our register access methods.  */
 815   t->to_fetch_registers = aarch64_linux_fetch_inferior_registers;
 816   t->to_store_registers = aarch64_linux_store_inferior_registers;
 817
 818   t->to_read_description = aarch64_linux_read_description;
 819
 820   t->to_can_use_hw_breakpoint = aarch64_linux_can_use_hw_breakpoint;
 821   t->to_insert_hw_breakpoint = aarch64_linux_insert_hw_breakpoint;
 822   t->to_remove_hw_breakpoint = aarch64_linux_remove_hw_breakpoint;
 823   t->to_region_ok_for_hw_watchpoint =
 824     aarch64_linux_region_ok_for_hw_watchpoint;
 825   t->to_insert_watchpoint = aarch64_linux_insert_watchpoint;
 826   t->to_remove_watchpoint = aarch64_linux_remove_watchpoint;
 827   t->to_stopped_by_watchpoint = aarch64_linux_stopped_by_watchpoint;
 828   t->to_stopped_data_address = aarch64_linux_stopped_data_address;
 829   t->to_watchpoint_addr_within_range =
 830     aarch64_linux_watchpoint_addr_within_range;
 831   t->to_can_do_single_step = aarch64_linux_can_do_single_step;
 832
 833   /* Override the GNU/Linux inferior startup hook.  */
 834   super_post_startup_inferior = t->to_post_startup_inferior;
 835   t->to_post_startup_inferior = aarch64_linux_child_post_startup_inferior;
 836
 837   /* Register the target.  */
 838   linux_nat_add_target (t);
 839   linux_nat_set_new_thread (t, aarch64_linux_new_thread);
 840   linux_nat_set_new_fork (t, aarch64_linux_new_fork);
 841   linux_nat_set_forget_process (t, aarch64_forget_process);
 842   linux_nat_set_prepare_to_resume (t, aarch64_linux_prepare_to_resume);
 843
 844   /* Add our siginfo layout converter.  */
 845   linux_nat_set_siginfo_fixup (t, aarch64_linux_siginfo_fixup);
 846 }