gdbserver/linux-low.h

   1 /* Internal interfaces for the GNU/Linux specific target code for gdbserver.
   2    Copyright (C) 2002-2020 Free Software Foundation, Inc.
   3
   4    This file is part of GDB.
   5
   6    This program is free software; you can redistribute it and/or modify
   7    it under the terms of the GNU General Public License as published by
   8    the Free Software Foundation; either version 3 of the License, or
   9    (at your option) any later version.
  10
  11    This program is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14    GNU General Public License for more details.
  15
  16    You should have received a copy of the GNU General Public License
  17    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
  18
  19 #ifndef GDBSERVER_LINUX_LOW_H
  20 #define GDBSERVER_LINUX_LOW_H
  21
  22 #include "nat/linux-nat.h"
  23 #include "nat/gdb_thread_db.h"
  24 #include <signal.h>
  25
  26 #include "gdbthread.h"
  27 #include "gdb_proc_service.h"
  28
  29 /* Included for ptrace type definitions.  */
  30 #include "nat/linux-ptrace.h"
  31 #include "target/waitstatus.h" /* For enum target_stop_reason.  */
  32 #include "tracepoint.h"
  33
  34 #define PTRACE_XFER_TYPE long
  35
  36 #ifdef HAVE_LINUX_REGSETS
  37 typedef void (*regset_fill_func) (struct regcache *, void *);
  38 typedef void (*regset_store_func) (struct regcache *, const void *);
  39 enum regset_type {
  40   GENERAL_REGS,
  41   FP_REGS,
  42   EXTENDED_REGS,
  43   OPTIONAL_REGS, /* Do not error if the regset cannot be accessed.  */
  44 };
  45
  46 /* The arch's regsets array initializer must be terminated with a NULL
  47    regset.  */
  48 #define NULL_REGSET \
  49   { 0, 0, 0, -1, (enum regset_type) -1, NULL, NULL }
  50
  51 struct regset_info
  52 {
  53   int get_request, set_request;
  54   /* If NT_TYPE isn't 0, it will be passed to ptrace as the 3rd
  55      argument and the 4th argument should be "const struct iovec *".  */
  56   int nt_type;
  57   int size;
  58   enum regset_type type;
  59   regset_fill_func fill_function;
  60   regset_store_func store_function;
  61 };
  62
  63 /* Aggregation of all the supported regsets of a given
  64    architecture/mode.  */
  65
  66 struct regsets_info
  67 {
  68   /* The regsets array.  */
  69   struct regset_info *regsets;
  70
  71   /* The number of regsets in the REGSETS array.  */
  72   int num_regsets;
  73
  74   /* If we get EIO on a regset, do not try it again.  Note the set of
  75      supported regsets may depend on processor mode on biarch
  76      machines.  This is a (lazily allocated) array holding one boolean
  77      byte (0/1) per regset, with each element corresponding to the
  78      regset in the REGSETS array above at the same offset.  */
  79   char *disabled_regsets;
  80 };
  81
  82 #endif
  83
  84 /* Mapping between the general-purpose registers in `struct user'
  85    format and GDB's register array layout.  */
  86
  87 struct usrregs_info
  88 {
  89   /* The number of registers accessible.  */
  90   int num_regs;
  91
  92   /* The registers map.  */
  93   int *regmap;
  94 };
  95
  96 /* All info needed to access an architecture/mode's registers.  */
  97
  98 struct regs_info
  99 {
 100   /* Regset support bitmap: 1 for registers that are transferred as a part
 101      of a regset, 0 for ones that need to be handled individually.  This
 102      can be NULL if all registers are transferred with regsets or regsets
 103      are not supported.  */
 104   unsigned char *regset_bitmap;
 105
 106   /* Info used when accessing registers with PTRACE_PEEKUSER /
 107      PTRACE_POKEUSER.  This can be NULL if all registers are
 108      transferred with regsets  .*/
 109   struct usrregs_info *usrregs;
 110
 111 #ifdef HAVE_LINUX_REGSETS
 112   /* Info used when accessing registers with regsets.  */
 113   struct regsets_info *regsets_info;
 114 #endif
 115 };
 116
 117 struct process_info_private
 118 {
 119   /* Arch-specific additions.  */
 120   struct arch_process_info *arch_private;
 121
 122   /* libthread_db-specific additions.  Not NULL if this process has loaded
 123      thread_db, and it is active.  */
 124   struct thread_db *thread_db;
 125
 126   /* &_r_debug.  0 if not yet determined.  -1 if no PT_DYNAMIC in Phdrs.  */
 127   CORE_ADDR r_debug;
 128 };
 129
 130 struct lwp_info;
 131
 132 struct linux_target_ops
 133 {
 134   /* Install a fast tracepoint jump pad.  See target.h for
 135      comments.  */
 136   int (*install_fast_tracepoint_jump_pad) (CORE_ADDR tpoint, CORE_ADDR tpaddr,
 137                                            CORE_ADDR collector,
 138                                            CORE_ADDR lockaddr,
 139                                            ULONGEST orig_size,
 140                                            CORE_ADDR *jump_entry,
 141                                            CORE_ADDR *trampoline,
 142                                            ULONGEST *trampoline_size,
 143                                            unsigned char *jjump_pad_insn,
 144                                            ULONGEST *jjump_pad_insn_size,
 145                                            CORE_ADDR *adjusted_insn_addr,
 146                                            CORE_ADDR *adjusted_insn_addr_end,
 147                                            char *err);
 148
 149   /* Return the bytecode operations vector for the current inferior.
 150      Returns NULL if bytecode compilation is not supported.  */
 151   struct emit_ops *(*emit_ops) (void);
 152
 153   /* Return the minimum length of an instruction that can be safely overwritten
 154      for use as a fast tracepoint.  */
 155   int (*get_min_fast_tracepoint_insn_len) (void);
 156
 157   /* Returns true if the low target supports range stepping.  */
 158   int (*supports_range_stepping) (void);
 159
 160   /* See target.h.  */
 161   int (*supports_hardware_single_step) (void);
 162
 163   /* Fill *SYSNO with the syscall nr trapped.  Only to be called when
 164      inferior is stopped due to SYSCALL_SIGTRAP.  */
 165   void (*get_syscall_trapinfo) (struct regcache *regcache, int *sysno);
 166
 167   /* See target.h.  */
 168   int (*get_ipa_tdesc_idx) (void);
 169 };
 170
 171 extern struct linux_target_ops the_low_target;
 172
 173 /* Target ops definitions for a Linux target.  */
 174
 175 class linux_process_target : public process_stratum_target
 176 {
 177 public:
 178
 179   int create_inferior (const char *program,
 180                        const std::vector<char *> &program_args) override;
 181
 182   void post_create_inferior () override;
 183
 184   int attach (unsigned long pid) override;
 185
 186   int kill (process_info *proc) override;
 187
 188   int detach (process_info *proc) override;
 189
 190   void mourn (process_info *proc) override;
 191
 192   void join (int pid) override;
 193
 194   bool thread_alive (ptid_t pid) override;
 195
 196   void resume (thread_resume *resume_info, size_t n) override;
 197
 198   ptid_t wait (ptid_t ptid, target_waitstatus *status,
 199                int options) override;
 200
 201   void fetch_registers (regcache *regcache, int regno) override;
 202
 203   void store_registers (regcache *regcache, int regno) override;
 204
 205   int prepare_to_access_memory () override;
 206
 207   void done_accessing_memory () override;
 208
 209   int read_memory (CORE_ADDR memaddr, unsigned char *myaddr,
 210                    int len) override;
 211
 212   int write_memory (CORE_ADDR memaddr, const unsigned char *myaddr,
 213                     int len) override;
 214
 215   void look_up_symbols () override;
 216
 217   void request_interrupt () override;
 218
 219   bool supports_read_auxv () override;
 220
 221   int read_auxv (CORE_ADDR offset, unsigned char *myaddr,
 222                  unsigned int len) override;
 223
 224   int insert_point (enum raw_bkpt_type type, CORE_ADDR addr,
 225                     int size, raw_breakpoint *bp) override;
 226
 227   int remove_point (enum raw_bkpt_type type, CORE_ADDR addr,
 228                     int size, raw_breakpoint *bp) override;
 229
 230   bool stopped_by_sw_breakpoint () override;
 231
 232   bool supports_stopped_by_sw_breakpoint () override;
 233
 234   bool stopped_by_hw_breakpoint () override;
 235
 236   bool supports_stopped_by_hw_breakpoint () override;
 237
 238   bool supports_hardware_single_step () override;
 239
 240   bool stopped_by_watchpoint () override;
 241
 242   CORE_ADDR stopped_data_address () override;
 243
 244   bool supports_read_offsets () override;
 245
 246   int read_offsets (CORE_ADDR *text, CORE_ADDR *data) override;
 247
 248   bool supports_get_tls_address () override;
 249
 250   int get_tls_address (thread_info *thread, CORE_ADDR offset,
 251                        CORE_ADDR load_module, CORE_ADDR *address) override;
 252
 253   bool supports_qxfer_osdata () override;
 254
 255   int qxfer_osdata (const char *annex, unsigned char *readbuf,
 256                     unsigned const char *writebuf,
 257                     CORE_ADDR offset, int len) override;
 258
 259   bool supports_qxfer_siginfo () override;
 260
 261   int qxfer_siginfo (const char *annex, unsigned char *readbuf,
 262                      unsigned const char *writebuf,
 263                      CORE_ADDR offset, int len) override;
 264
 265   bool supports_non_stop () override;
 266
 267   bool async (bool enable) override;
 268
 269   int start_non_stop (bool enable) override;
 270
 271   bool supports_multi_process () override;
 272
 273   bool supports_fork_events () override;
 274
 275   bool supports_vfork_events () override;
 276
 277   bool supports_exec_events () override;
 278
 279   void handle_new_gdb_connection () override;
 280
 281   int handle_monitor_command (char *mon) override;
 282
 283   int core_of_thread (ptid_t ptid) override;
 284
 285 #if defined PT_GETDSBT || defined PTRACE_GETFDPIC
 286   bool supports_read_loadmap () override;
 287
 288   int read_loadmap (const char *annex, CORE_ADDR offset,
 289                     unsigned char *myaddr, unsigned int len) override;
 290 #endif
 291
 292   CORE_ADDR read_pc (regcache *regcache) override;
 293
 294   void write_pc (regcache *regcache, CORE_ADDR pc) override;
 295
 296   bool supports_thread_stopped () override;
 297
 298   bool thread_stopped (thread_info *thread) override;
 299
 300   void pause_all (bool freeze) override;
 301
 302   void unpause_all (bool unfreeze) override;
 303
 304   void stabilize_threads () override;
 305
 306   bool supports_fast_tracepoints () override;
 307
 308   int install_fast_tracepoint_jump_pad (CORE_ADDR tpoint,
 309                                         CORE_ADDR tpaddr,
 310                                         CORE_ADDR collector,
 311                                         CORE_ADDR lockaddr,
 312                                         ULONGEST orig_size,
 313                                         CORE_ADDR *jump_entry,
 314                                         CORE_ADDR *trampoline,
 315                                         ULONGEST *trampoline_size,
 316                                         unsigned char *jjump_pad_insn,
 317                                         ULONGEST *jjump_pad_insn_size,
 318                                         CORE_ADDR *adjusted_insn_addr,
 319                                         CORE_ADDR *adjusted_insn_addr_end,
 320                                         char *err) override;
 321
 322   int get_min_fast_tracepoint_insn_len () override;
 323
 324   struct emit_ops *emit_ops () override;
 325
 326   bool supports_disable_randomization () override;
 327
 328   bool supports_qxfer_libraries_svr4 () override;
 329
 330   int qxfer_libraries_svr4 (const char *annex,
 331                             unsigned char *readbuf,
 332                             unsigned const char *writebuf,
 333                             CORE_ADDR offset, int len) override;
 334
 335   bool supports_agent () override;
 336
 337 #ifdef HAVE_LINUX_BTRACE
 338   btrace_target_info *enable_btrace (ptid_t ptid,
 339                                      const btrace_config *conf) override;
 340
 341   int disable_btrace (btrace_target_info *tinfo) override;
 342
 343   int read_btrace (btrace_target_info *tinfo, buffer *buf,
 344                    enum btrace_read_type type) override;
 345
 346   int read_btrace_conf (const btrace_target_info *tinfo,
 347                         buffer *buf) override;
 348 #endif
 349
 350   bool supports_range_stepping () override;
 351
 352   bool supports_pid_to_exec_file () override;
 353
 354   char *pid_to_exec_file (int pid) override;
 355
 356   bool supports_multifs () override;
 357
 358   int multifs_open (int pid, const char *filename, int flags,
 359                     mode_t mode) override;
 360
 361   int multifs_unlink (int pid, const char *filename) override;
 362
 363   ssize_t multifs_readlink (int pid, const char *filename, char *buf,
 364                             size_t bufsiz) override;
 365
 366   const char *thread_name (ptid_t thread) override;
 367
 368 #if USE_THREAD_DB
 369   bool thread_handle (ptid_t ptid, gdb_byte **handle,
 370                       int *handle_len) override;
 371 #endif
 372
 373   bool supports_catch_syscall () override;
 374
 375   int get_ipa_tdesc_idx () override;
 376
 377   /* Return the information to access registers.  This has public
 378      visibility because proc-service uses it.  */
 379   virtual const regs_info *get_regs_info () = 0;
 380
 381 private:
 382
 383   /* Handle a GNU/Linux extended wait response.  If we see a clone,
 384      fork, or vfork event, we need to add the new LWP to our list
 385      (and return 0 so as not to report the trap to higher layers).
 386      If we see an exec event, we will modify ORIG_EVENT_LWP to point
 387      to a new LWP representing the new program.  */
 388   int handle_extended_wait (lwp_info **orig_event_lwp, int wstat);
 389
 390   /* Do low-level handling of the event, and check if we should go on
 391      and pass it to caller code.  Return the affected lwp if we are, or
 392      NULL otherwise.  */
 393   lwp_info *filter_event (int lwpid, int wstat);
 394
 395   /* Wait for an event from child(ren) WAIT_PTID, and return any that
 396      match FILTER_PTID (leaving others pending).  The PTIDs can be:
 397      minus_one_ptid, to specify any child; a pid PTID, specifying all
 398      lwps of a thread group; or a PTID representing a single lwp.  Store
 399      the stop status through the status pointer WSTAT.  OPTIONS is
 400      passed to the waitpid call.  Return 0 if no event was found and
 401      OPTIONS contains WNOHANG.  Return -1 if no unwaited-for children
 402      was found.  Return the PID of the stopped child otherwise.  */
 403   int wait_for_event_filtered (ptid_t wait_ptid, ptid_t filter_ptid,
 404                                int *wstatp, int options);
 405
 406   /* Wait for an event from child(ren) PTID.  PTIDs can be:
 407      minus_one_ptid, to specify any child; a pid PTID, specifying all
 408      lwps of a thread group; or a PTID representing a single lwp.  Store
 409      the stop status through the status pointer WSTAT.  OPTIONS is
 410      passed to the waitpid call.  Return 0 if no event was found and
 411      OPTIONS contains WNOHANG.  Return -1 if no unwaited-for children
 412      was found.  Return the PID of the stopped child otherwise.  */
 413   int wait_for_event (ptid_t ptid, int *wstatp, int options);
 414
 415   /* Wait for all children to stop for the SIGSTOPs we just queued.  */
 416   void wait_for_sigstop ();
 417
 418   /* Wait for process, returns status.  */
 419   ptid_t wait_1 (ptid_t ptid, target_waitstatus *ourstatus,
 420                  int target_options);
 421
 422   /* Stop all lwps that aren't stopped yet, except EXCEPT, if not NULL.
 423      If SUSPEND, then also increase the suspend count of every LWP,
 424      except EXCEPT.  */
 425   void stop_all_lwps (int suspend, lwp_info *except);
 426
 427   /* Stopped LWPs that the client wanted to be running, that don't have
 428      pending statuses, are set to run again, except for EXCEPT, if not
 429      NULL.  This undoes a stop_all_lwps call.  */
 430   void unstop_all_lwps (int unsuspend, lwp_info *except);
 431
 432   /* Start a step-over operation on LWP.  When LWP stopped at a
 433      breakpoint, to make progress, we need to remove the breakpoint out
 434      of the way.  If we let other threads run while we do that, they may
 435      pass by the breakpoint location and miss hitting it.  To avoid
 436      that, a step-over momentarily stops all threads while LWP is
 437      single-stepped by either hardware or software while the breakpoint
 438      is temporarily uninserted from the inferior.  When the single-step
 439      finishes, we reinsert the breakpoint, and let all threads that are
 440      supposed to be running, run again.  */
 441   void start_step_over (lwp_info *lwp);
 442
 443   /* If there's a step over in progress, wait until all threads stop
 444      (that is, until the stepping thread finishes its step), and
 445      unsuspend all lwps.  The stepping thread ends with its status
 446      pending, which is processed later when we get back to processing
 447      events.  */
 448   void complete_ongoing_step_over ();
 449
 450   /* When we finish a step-over, set threads running again.  If there's
 451      another thread that may need a step-over, now's the time to start
 452      it.  Eventually, we'll move all threads past their breakpoints.  */
 453   void proceed_all_lwps ();
 454
 455   /* The reason we resume in the caller, is because we want to be able
 456      to pass lwp->status_pending as WSTAT, and we need to clear
 457      status_pending_p before resuming, otherwise, resume_one_lwp
 458      refuses to resume.  */
 459   bool maybe_move_out_of_jump_pad (lwp_info *lwp, int *wstat);
 460
 461   /* Move THREAD out of the jump pad.  */
 462   void move_out_of_jump_pad (thread_info *thread);
 463
 464   /* Call low_arch_setup on THREAD.  */
 465   void arch_setup_thread (thread_info *thread);
 466
 467 #ifdef HAVE_LINUX_USRREGS
 468   /* Fetch one register.  */
 469   void fetch_register (const usrregs_info *usrregs, regcache *regcache,
 470                        int regno);
 471
 472   /* Store one register.  */
 473   void store_register (const usrregs_info *usrregs, regcache *regcache,
 474                        int regno);
 475 #endif
 476
 477   /* Fetch all registers, or just one, from the child process.
 478      If REGNO is -1, do this for all registers, skipping any that are
 479      assumed to have been retrieved by regsets_fetch_inferior_registers,
 480      unless ALL is non-zero.
 481      Otherwise, REGNO specifies which register (so we can save time).  */
 482   void usr_fetch_inferior_registers (const regs_info *regs_info,
 483                                      regcache *regcache, int regno, int all);
 484
 485   /* Store our register values back into the inferior.
 486      If REGNO is -1, do this for all registers, skipping any that are
 487      assumed to have been saved by regsets_store_inferior_registers,
 488      unless ALL is non-zero.
 489      Otherwise, REGNO specifies which register (so we can save time).  */
 490   void usr_store_inferior_registers (const regs_info *regs_info,
 491                                      regcache *regcache, int regno, int all);
 492
 493   /* Return the PC as read from the regcache of LWP, without any
 494      adjustment.  */
 495   CORE_ADDR get_pc (lwp_info *lwp);
 496
 497   /* Called when the LWP stopped for a signal/trap.  If it stopped for a
 498      trap check what caused it (breakpoint, watchpoint, trace, etc.),
 499      and save the result in the LWP's stop_reason field.  If it stopped
 500      for a breakpoint, decrement the PC if necessary on the lwp's
 501      architecture.  Returns true if we now have the LWP's stop PC.  */
 502   bool save_stop_reason (lwp_info *lwp);
 503
 504   /* Resume execution of LWP.  If STEP is nonzero, single-step it.  If
 505      SIGNAL is nonzero, give it that signal.  */
 506   void resume_one_lwp_throw (lwp_info *lwp, int step, int signal,
 507                              siginfo_t *info);
 508
 509   /* Like resume_one_lwp_throw, but no error is thrown if the LWP
 510      disappears while we try to resume it.  */
 511   void resume_one_lwp (lwp_info *lwp, int step, int signal, siginfo_t *info);
 512
 513   /* This function is called once per thread.  We check the thread's
 514      last resume request, which will tell us whether to resume, step, or
 515      leave the thread stopped.  Any signal the client requested to be
 516      delivered has already been enqueued at this point.
 517
 518      If any thread that GDB wants running is stopped at an internal
 519      breakpoint that needs stepping over, we start a step-over operation
 520      on that particular thread, and leave all others stopped.  */
 521   void proceed_one_lwp (thread_info *thread, lwp_info *except);
 522
 523   /* This function is called once per thread.  We check the thread's
 524      resume request, which will tell us whether to resume, step, or
 525      leave the thread stopped; and what signal, if any, it should be
 526      sent.
 527
 528      For threads which we aren't explicitly told otherwise, we preserve
 529      the stepping flag; this is used for stepping over gdbserver-placed
 530      breakpoints.
 531
 532      If pending_flags was set in any thread, we queue any needed
 533      signals, since we won't actually resume.  We already have a pending
 534      event to report, so we don't need to preserve any step requests;
 535      they should be re-issued if necessary.  */
 536   void resume_one_thread (thread_info *thread, bool leave_all_stopped);
 537
 538   /* Return true if this lwp has an interesting status pending.  */
 539   bool status_pending_p_callback (thread_info *thread, ptid_t ptid);
 540
 541   /* Resume LWPs that are currently stopped without any pending status
 542      to report, but are resumed from the core's perspective.  */
 543   void resume_stopped_resumed_lwps (thread_info *thread);
 544
 545   /* Unsuspend THREAD, except EXCEPT, and proceed.  */
 546   void unsuspend_and_proceed_one_lwp (thread_info *thread, lwp_info *except);
 547
 548   /* Return true if this lwp still has an interesting status pending.
 549      If not (e.g., it had stopped for a breakpoint that is gone), return
 550      false.  */
 551   bool thread_still_has_status_pending (thread_info *thread);
 552
 553   /* Return true if this lwp is to-be-resumed and has an interesting
 554      status pending.  */
 555   bool resume_status_pending (thread_info *thread);
 556
 557   /* Return true if this lwp that GDB wants running is stopped at an
 558      internal breakpoint that we need to step over.  It assumes that
 559      any required STOP_PC adjustment has already been propagated to
 560      the inferior's regcache.  */
 561   bool thread_needs_step_over (thread_info *thread);
 562
 563   /* Single step via hardware or software single step.
 564      Return 1 if hardware single stepping, 0 if software single stepping
 565      or can't single step.  */
 566   int single_step (lwp_info* lwp);
 567
 568   /* Install breakpoints for software single stepping.  */
 569   void install_software_single_step_breakpoints (lwp_info *lwp);
 570
 571   /* Fetch the possibly triggered data watchpoint info and store it in
 572      CHILD.
 573
 574      On some archs, like x86, that use debug registers to set
 575      watchpoints, it's possible that the way to know which watched
 576      address trapped, is to check the register that is used to select
 577      which address to watch.  Problem is, between setting the watchpoint
 578      and reading back which data address trapped, the user may change
 579      the set of watchpoints, and, as a consequence, GDB changes the
 580      debug registers in the inferior.  To avoid reading back a stale
 581      stopped-data-address when that happens, we cache in LP the fact
 582      that a watchpoint trapped, and the corresponding data address, as
 583      soon as we see CHILD stop with a SIGTRAP.  If GDB changes the debug
 584      registers meanwhile, we have the cached data we can rely on.  */
 585   bool check_stopped_by_watchpoint (lwp_info *child);
 586
 587   /* Convert a native/host siginfo object, into/from the siginfo in the
 588      layout of the inferiors' architecture.  */
 589   void siginfo_fixup (siginfo_t *siginfo, gdb_byte *inf_siginfo,
 590                       int direction);
 591
 592   /* Add a process to the common process list, and set its private
 593      data.  */
 594   process_info *add_linux_process (int pid, int attached);
 595
 596   /* Add a new thread.  */
 597   lwp_info *add_lwp (ptid_t ptid);
 598
 599   /* Delete a thread.  */
 600   void delete_lwp (lwp_info *lwp);
 601
 602 public: /* Make this public because it's used from outside.  */
 603   /* Attach to an inferior process.  Returns 0 on success, ERRNO on
 604      error.  */
 605   int attach_lwp (ptid_t ptid);
 606
 607 private: /* Back to private.  */
 608   /* Detach from LWP.  */
 609   void detach_one_lwp (lwp_info *lwp);
 610
 611   /* Detect zombie thread group leaders, and "exit" them.  We can't
 612      reap their exits until all other threads in the group have
 613      exited.  */
 614   void check_zombie_leaders ();
 615
 616   /* Convenience function that is called when the kernel reports an exit
 617      event.  This decides whether to report the event to GDB as a
 618      process exit event, a thread exit event, or to suppress the
 619      event.  */
 620   ptid_t filter_exit_event (lwp_info *event_child,
 621                             target_waitstatus *ourstatus);
 622
 623   /* Returns true if THREAD is stopped in a jump pad, and we can't
 624      move it out, because we need to report the stop event to GDB.  For
 625      example, if the user puts a breakpoint in the jump pad, it's
 626      because she wants to debug it.  */
 627   bool stuck_in_jump_pad (thread_info *thread);
 628
 629   /* Convenience wrapper.  Returns information about LWP's fast tracepoint
 630      collection status.  */
 631   fast_tpoint_collect_result linux_fast_tracepoint_collecting
 632     (lwp_info *lwp, fast_tpoint_collect_status *status);
 633
 634 protected:
 635   /* The architecture-specific "low" methods are listed below.  */
 636
 637   /* Architecture-specific setup for the current thread.  */
 638   virtual void low_arch_setup () = 0;
 639
 640   /* Return false if we can fetch/store the register, true if we cannot
 641      fetch/store the register.  */
 642   virtual bool low_cannot_fetch_register (int regno) = 0;
 643
 644   virtual bool low_cannot_store_register (int regno) = 0;
 645
 646   /* Hook to fetch a register in some non-standard way.  Used for
 647      example by backends that have read-only registers with hardcoded
 648      values (e.g., IA64's gr0/fr0/fr1).  Returns true if register
 649      REGNO was supplied, false if not, and we should fallback to the
 650      standard ptrace methods.  */
 651   virtual bool low_fetch_register (regcache *regcache, int regno);
 652
 653   /* Return true if breakpoints are supported.  Such targets must
 654      implement the GET_PC and SET_PC methods.  */
 655   virtual bool low_supports_breakpoints ();
 656
 657   virtual CORE_ADDR low_get_pc (regcache *regcache);
 658
 659   virtual void low_set_pc (regcache *regcache, CORE_ADDR newpc);
 660
 661   /* Find the next possible PCs after the current instruction executes.
 662      Targets that override this method should also override
 663      'supports_software_single_step' to return true.  */
 664   virtual std::vector<CORE_ADDR> low_get_next_pcs (regcache *regcache);
 665
 666   /* Return true if there is a breakpoint at PC.  */
 667   virtual bool low_breakpoint_at (CORE_ADDR pc) = 0;
 668
 669   /* Breakpoint and watchpoint related functions.  See target.h for
 670      comments.  */
 671   virtual int low_insert_point (raw_bkpt_type type, CORE_ADDR addr,
 672                                 int size, raw_breakpoint *bp);
 673
 674   virtual int low_remove_point (raw_bkpt_type type, CORE_ADDR addr,
 675                                 int size, raw_breakpoint *bp);
 676
 677   virtual bool low_stopped_by_watchpoint ();
 678
 679   virtual CORE_ADDR low_stopped_data_address ();
 680
 681   /* Hooks to reformat register data for PEEKUSR/POKEUSR (in particular
 682      for registers smaller than an xfer unit).  */
 683   virtual void low_collect_ptrace_register (regcache *regcache, int regno,
 684                                             char *buf);
 685
 686   virtual void low_supply_ptrace_register (regcache *regcache, int regno,
 687                                            const char *buf);
 688
 689   /* Hook to convert from target format to ptrace format and back.
 690      Returns true if any conversion was done; false otherwise.
 691      If DIRECTION is 1, then copy from INF to NATIVE.
 692      If DIRECTION is 0, copy from NATIVE to INF.  */
 693   virtual bool low_siginfo_fixup (siginfo_t *native, gdb_byte *inf,
 694                                   int direction);
 695
 696   /* Hook to call when a new process is created or attached to.
 697      If extra per-process architecture-specific data is needed,
 698      allocate it here.  */
 699   virtual arch_process_info *low_new_process ();
 700
 701   /* Hook to call when a process is being deleted.  If extra per-process
 702      architecture-specific data is needed, delete it here.  */
 703   virtual void low_delete_process (arch_process_info *info);
 704
 705   /* Hook to call when a new thread is detected.
 706      If extra per-thread architecture-specific data is needed,
 707      allocate it here.  */
 708   virtual void low_new_thread (lwp_info *);
 709
 710   /* Hook to call when a thread is being deleted.  If extra per-thread
 711      architecture-specific data is needed, delete it here.  */
 712   virtual void low_delete_thread (arch_lwp_info *);
 713
 714   /* Hook to call, if any, when a new fork is attached.  */
 715   virtual void low_new_fork (process_info *parent, process_info *child);
 716
 717   /* Hook to call prior to resuming a thread.  */
 718   virtual void low_prepare_to_resume (lwp_info *lwp);
 719
 720   /* Fill ADDRP with the thread area address of LWPID.  Returns 0 on
 721      success, -1 on failure.  */
 722   virtual int low_get_thread_area (int lwpid, CORE_ADDR *addrp);
 723
 724   /* How many bytes the PC should be decremented after a break.  */
 725   virtual int low_decr_pc_after_break ();
 726 };
 727
 728 extern linux_process_target *the_linux_target;
 729
 730 #define get_thread_lwp(thr) ((struct lwp_info *) (thread_target_data (thr)))
 731 #define get_lwp_thread(lwp) ((lwp)->thread)
 732
 733 /* This struct is recorded in the target_data field of struct thread_info.
 734
 735    On linux ``all_threads'' is keyed by the LWP ID, which we use as the
 736    GDB protocol representation of the thread ID.  Threads also have
 737    a "process ID" (poorly named) which is (presently) the same as the
 738    LWP ID.
 739
 740    There is also ``all_processes'' is keyed by the "overall process ID",
 741    which GNU/Linux calls tgid, "thread group ID".  */
 742
 743 struct lwp_info
 744 {
 745   /* Backlink to the parent object.  */
 746   struct thread_info *thread;
 747
 748   /* If this flag is set, the next SIGSTOP will be ignored (the
 749      process will be immediately resumed).  This means that either we
 750      sent the SIGSTOP to it ourselves and got some other pending event
 751      (so the SIGSTOP is still pending), or that we stopped the
 752      inferior implicitly via PTRACE_ATTACH and have not waited for it
 753      yet.  */
 754   int stop_expected;
 755
 756   /* When this is true, we shall not try to resume this thread, even
 757      if last_resume_kind isn't resume_stop.  */
 758   int suspended;
 759
 760   /* If this flag is set, the lwp is known to be stopped right now (stop
 761      event already received in a wait()).  */
 762   int stopped;
 763
 764   /* Signal whether we are in a SYSCALL_ENTRY or
 765      in a SYSCALL_RETURN event.
 766      Values:
 767      - TARGET_WAITKIND_SYSCALL_ENTRY
 768      - TARGET_WAITKIND_SYSCALL_RETURN */
 769   enum target_waitkind syscall_state;
 770
 771   /* When stopped is set, the last wait status recorded for this lwp.  */
 772   int last_status;
 773
 774   /* If WAITSTATUS->KIND != TARGET_WAITKIND_IGNORE, the waitstatus for
 775      this LWP's last event, to pass to GDB without any further
 776      processing.  This is used to store extended ptrace event
 777      information or exit status until it can be reported to GDB.  */
 778   struct target_waitstatus waitstatus;
 779
 780   /* A pointer to the fork child/parent relative.  Valid only while
 781      the parent fork event is not reported to higher layers.  Used to
 782      avoid wildcard vCont actions resuming a fork child before GDB is
 783      notified about the parent's fork event.  */
 784   struct lwp_info *fork_relative;
 785
 786   /* When stopped is set, this is where the lwp last stopped, with
 787      decr_pc_after_break already accounted for.  If the LWP is
 788      running, this is the address at which the lwp was resumed.  */
 789   CORE_ADDR stop_pc;
 790
 791   /* If this flag is set, STATUS_PENDING is a waitstatus that has not yet
 792      been reported.  */
 793   int status_pending_p;
 794   int status_pending;
 795
 796   /* The reason the LWP last stopped, if we need to track it
 797      (breakpoint, watchpoint, etc.)  */
 798   enum target_stop_reason stop_reason;
 799
 800   /* On architectures where it is possible to know the data address of
 801      a triggered watchpoint, STOPPED_DATA_ADDRESS is non-zero, and
 802      contains such data address.  Only valid if STOPPED_BY_WATCHPOINT
 803      is true.  */
 804   CORE_ADDR stopped_data_address;
 805
 806   /* If this is non-zero, it is a breakpoint to be reinserted at our next
 807      stop (SIGTRAP stops only).  */
 808   CORE_ADDR bp_reinsert;
 809
 810   /* If this flag is set, the last continue operation at the ptrace
 811      level on this process was a single-step.  */
 812   int stepping;
 813
 814   /* Range to single step within.  This is a copy of the step range
 815      passed along the last resume request.  See 'struct
 816      thread_resume'.  */
 817   CORE_ADDR step_range_start;   /* Inclusive */
 818   CORE_ADDR step_range_end;     /* Exclusive */
 819
 820   /* If this flag is set, we need to set the event request flags the
 821      next time we see this LWP stop.  */
 822   int must_set_ptrace_flags;
 823
 824   /* If this is non-zero, it points to a chain of signals which need to
 825      be delivered to this process.  */
 826   struct pending_signals *pending_signals;
 827
 828   /* A link used when resuming.  It is initialized from the resume request,
 829      and then processed and cleared in linux_resume_one_lwp.  */
 830   struct thread_resume *resume;
 831
 832   /* Information bout this lwp's fast tracepoint collection status (is it
 833      currently stopped in the jump pad, and if so, before or at/after the
 834      relocated instruction).  Normally, we won't care about this, but we will
 835      if a signal arrives to this lwp while it is collecting.  */
 836   fast_tpoint_collect_result collecting_fast_tracepoint;
 837
 838   /* If this is non-zero, it points to a chain of signals which need
 839      to be reported to GDB.  These were deferred because the thread
 840      was doing a fast tracepoint collect when they arrived.  */
 841   struct pending_signals *pending_signals_to_report;
 842
 843   /* When collecting_fast_tracepoint is first found to be 1, we insert
 844      a exit-jump-pad-quickly breakpoint.  This is it.  */
 845   struct breakpoint *exit_jump_pad_bkpt;
 846
 847 #ifdef USE_THREAD_DB
 848   int thread_known;
 849   /* The thread handle, used for e.g. TLS access.  Only valid if
 850      THREAD_KNOWN is set.  */
 851   td_thrhandle_t th;
 852
 853   /* The pthread_t handle.  */
 854   thread_t thread_handle;
 855 #endif
 856
 857   /* Arch-specific additions.  */
 858   struct arch_lwp_info *arch_private;
 859 };
 860
 861 int linux_pid_exe_is_elf_64_file (int pid, unsigned int *machine);
 862
 863 /* Attach to PTID.  Returns 0 on success, non-zero otherwise (an
 864    errno).  */
 865 int linux_attach_lwp (ptid_t ptid);
 866
 867 struct lwp_info *find_lwp_pid (ptid_t ptid);
 868 /* For linux_stop_lwp see nat/linux-nat.h.  */
 869
 870 #ifdef HAVE_LINUX_REGSETS
 871 void initialize_regsets_info (struct regsets_info *regsets_info);
 872 #endif
 873
 874 void initialize_low_arch (void);
 875
 876 void linux_set_pc_32bit (struct regcache *regcache, CORE_ADDR pc);
 877 CORE_ADDR linux_get_pc_32bit (struct regcache *regcache);
 878
 879 void linux_set_pc_64bit (struct regcache *regcache, CORE_ADDR pc);
 880 CORE_ADDR linux_get_pc_64bit (struct regcache *regcache);
 881
 882 /* From thread-db.c  */
 883 int thread_db_init (void);
 884 void thread_db_detach (struct process_info *);
 885 void thread_db_mourn (struct process_info *);
 886 int thread_db_handle_monitor_command (char *);
 887 int thread_db_get_tls_address (struct thread_info *thread, CORE_ADDR offset,
 888                                CORE_ADDR load_module, CORE_ADDR *address);
 889 int thread_db_look_up_one_symbol (const char *name, CORE_ADDR *addrp);
 890
 891 /* Called from linux-low.c when a clone event is detected.  Upon entry,
 892    both the clone and the parent should be stopped.  This function does
 893    whatever is required have the clone under thread_db's control.  */
 894
 895 void thread_db_notice_clone (struct thread_info *parent_thr, ptid_t child_ptid);
 896
 897 bool thread_db_thread_handle (ptid_t ptid, gdb_byte **handle, int *handle_len);
 898
 899 extern int have_ptrace_getregset;
 900
 901 /* Search for the value with type MATCH in the auxv vector with
 902    entries of length WORDSIZE bytes.  If found, store the value in
 903    *VALP and return 1.  If not found or if there is an error, return
 904    0.  */
 905
 906 int linux_get_auxv (int wordsize, CORE_ADDR match,
 907                     CORE_ADDR *valp);
 908
 909 /* Fetch the AT_HWCAP entry from the auxv vector, where entries are length
 910    WORDSIZE.  If no entry was found, return zero.  */
 911
 912 CORE_ADDR linux_get_hwcap (int wordsize);
 913
 914 /* Fetch the AT_HWCAP2 entry from the auxv vector, where entries are length
 915    WORDSIZE.  If no entry was found, return zero.  */
 916
 917 CORE_ADDR linux_get_hwcap2 (int wordsize);
 918
 919 #endif /* GDBSERVER_LINUX_LOW_H */