gdbserver/linux-low.h

   1 /* Internal interfaces for the GNU/Linux specific target code for gdbserver.
   2    Copyright (C) 2002-2021 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 #include <list>
  35
  36 #define PTRACE_XFER_TYPE long
  37
  38 #ifdef HAVE_LINUX_REGSETS
  39 typedef void (*regset_fill_func) (struct regcache *, void *);
  40 typedef void (*regset_store_func) (struct regcache *, const void *);
  41 enum regset_type {
  42   GENERAL_REGS,
  43   FP_REGS,
  44   EXTENDED_REGS,
  45   OPTIONAL_REGS, /* Do not error if the regset cannot be accessed.  */
  46 };
  47
  48 /* The arch's regsets array initializer must be terminated with a NULL
  49    regset.  */
  50 #define NULL_REGSET \
  51   { 0, 0, 0, -1, (enum regset_type) -1, NULL, NULL }
  52
  53 struct regset_info
  54 {
  55   int get_request, set_request;
  56   /* If NT_TYPE isn't 0, it will be passed to ptrace as the 3rd
  57      argument and the 4th argument should be "const struct iovec *".  */
  58   int nt_type;
  59   int size;
  60   enum regset_type type;
  61   regset_fill_func fill_function;
  62   regset_store_func store_function;
  63 };
  64
  65 /* Aggregation of all the supported regsets of a given
  66    architecture/mode.  */
  67
  68 struct regsets_info
  69 {
  70   /* The regsets array.  */
  71   struct regset_info *regsets;
  72
  73   /* The number of regsets in the REGSETS array.  */
  74   int num_regsets;
  75
  76   /* If we get EIO on a regset, do not try it again.  Note the set of
  77      supported regsets may depend on processor mode on biarch
  78      machines.  This is a (lazily allocated) array holding one boolean
  79      byte (0/1) per regset, with each element corresponding to the
  80      regset in the REGSETS array above at the same offset.  */
  81   char *disabled_regsets;
  82 };
  83
  84 #endif
  85
  86 /* Mapping between the general-purpose registers in `struct user'
  87    format and GDB's register array layout.  */
  88
  89 struct usrregs_info
  90 {
  91   /* The number of registers accessible.  */
  92   int num_regs;
  93
  94   /* The registers map.  */
  95   int *regmap;
  96 };
  97
  98 /* All info needed to access an architecture/mode's registers.  */
  99
 100 struct regs_info
 101 {
 102   /* Regset support bitmap: 1 for registers that are transferred as a part
 103      of a regset, 0 for ones that need to be handled individually.  This
 104      can be NULL if all registers are transferred with regsets or regsets
 105      are not supported.  */
 106   unsigned char *regset_bitmap;
 107
 108   /* Info used when accessing registers with PTRACE_PEEKUSER /
 109      PTRACE_POKEUSER.  This can be NULL if all registers are
 110      transferred with regsets  .*/
 111   struct usrregs_info *usrregs;
 112
 113 #ifdef HAVE_LINUX_REGSETS
 114   /* Info used when accessing registers with regsets.  */
 115   struct regsets_info *regsets_info;
 116 #endif
 117 };
 118
 119 struct process_info_private
 120 {
 121   /* Arch-specific additions.  */
 122   struct arch_process_info *arch_private;
 123
 124   /* libthread_db-specific additions.  Not NULL if this process has loaded
 125      thread_db, and it is active.  */
 126   struct thread_db *thread_db;
 127
 128   /* &_r_debug.  0 if not yet determined.  -1 if no PT_DYNAMIC in Phdrs.  */
 129   CORE_ADDR r_debug;
 130 };
 131
 132 struct lwp_info;
 133
 134 /* Target ops definitions for a Linux target.  */
 135
 136 class linux_process_target : public process_stratum_target
 137 {
 138 public:
 139
 140   int create_inferior (const char *program,
 141                        const std::vector<char *> &program_args) override;
 142
 143   void post_create_inferior () override;
 144
 145   int attach (unsigned long pid) override;
 146
 147   int kill (process_info *proc) override;
 148
 149   int detach (process_info *proc) override;
 150
 151   void mourn (process_info *proc) override;
 152
 153   void join (int pid) override;
 154
 155   bool thread_alive (ptid_t pid) override;
 156
 157   void resume (thread_resume *resume_info, size_t n) override;
 158
 159   ptid_t wait (ptid_t ptid, target_waitstatus *status,
 160                target_wait_flags options) override;
 161
 162   void fetch_registers (regcache *regcache, int regno) override;
 163
 164   void store_registers (regcache *regcache, int regno) override;
 165
 166   int prepare_to_access_memory () override;
 167
 168   void done_accessing_memory () override;
 169
 170   int read_memory (CORE_ADDR memaddr, unsigned char *myaddr,
 171                    int len) override;
 172
 173   int write_memory (CORE_ADDR memaddr, const unsigned char *myaddr,
 174                     int len) override;
 175
 176   void look_up_symbols () override;
 177
 178   void request_interrupt () override;
 179
 180   bool supports_read_auxv () override;
 181
 182   int read_auxv (CORE_ADDR offset, unsigned char *myaddr,
 183                  unsigned int len) override;
 184
 185   int insert_point (enum raw_bkpt_type type, CORE_ADDR addr,
 186                     int size, raw_breakpoint *bp) override;
 187
 188   int remove_point (enum raw_bkpt_type type, CORE_ADDR addr,
 189                     int size, raw_breakpoint *bp) override;
 190
 191   bool stopped_by_sw_breakpoint () override;
 192
 193   bool supports_stopped_by_sw_breakpoint () override;
 194
 195   bool stopped_by_hw_breakpoint () override;
 196
 197   bool supports_stopped_by_hw_breakpoint () override;
 198
 199   bool supports_hardware_single_step () override;
 200
 201   bool stopped_by_watchpoint () override;
 202
 203   CORE_ADDR stopped_data_address () override;
 204
 205   bool supports_read_offsets () override;
 206
 207   int read_offsets (CORE_ADDR *text, CORE_ADDR *data) override;
 208
 209   bool supports_get_tls_address () override;
 210
 211   int get_tls_address (thread_info *thread, CORE_ADDR offset,
 212                        CORE_ADDR load_module, CORE_ADDR *address) override;
 213
 214   bool supports_qxfer_osdata () override;
 215
 216   int qxfer_osdata (const char *annex, unsigned char *readbuf,
 217                     unsigned const char *writebuf,
 218                     CORE_ADDR offset, int len) override;
 219
 220   bool supports_qxfer_siginfo () override;
 221
 222   int qxfer_siginfo (const char *annex, unsigned char *readbuf,
 223                      unsigned const char *writebuf,
 224                      CORE_ADDR offset, int len) override;
 225
 226   bool supports_non_stop () override;
 227
 228   bool async (bool enable) override;
 229
 230   int start_non_stop (bool enable) override;
 231
 232   bool supports_multi_process () override;
 233
 234   bool supports_fork_events () override;
 235
 236   bool supports_vfork_events () override;
 237
 238   bool supports_exec_events () override;
 239
 240   void handle_new_gdb_connection () override;
 241
 242   int handle_monitor_command (char *mon) override;
 243
 244   int core_of_thread (ptid_t ptid) override;
 245
 246 #if defined PT_GETDSBT || defined PTRACE_GETFDPIC
 247   bool supports_read_loadmap () override;
 248
 249   int read_loadmap (const char *annex, CORE_ADDR offset,
 250                     unsigned char *myaddr, unsigned int len) override;
 251 #endif
 252
 253   CORE_ADDR read_pc (regcache *regcache) override;
 254
 255   void write_pc (regcache *regcache, CORE_ADDR pc) override;
 256
 257   bool supports_thread_stopped () override;
 258
 259   bool thread_stopped (thread_info *thread) override;
 260
 261   void pause_all (bool freeze) override;
 262
 263   void unpause_all (bool unfreeze) override;
 264
 265   void stabilize_threads () override;
 266
 267   bool supports_disable_randomization () override;
 268
 269   bool supports_qxfer_libraries_svr4 () override;
 270
 271   int qxfer_libraries_svr4 (const char *annex,
 272                             unsigned char *readbuf,
 273                             unsigned const char *writebuf,
 274                             CORE_ADDR offset, int len) override;
 275
 276   bool supports_agent () override;
 277
 278 #ifdef HAVE_LINUX_BTRACE
 279   btrace_target_info *enable_btrace (ptid_t ptid,
 280                                      const btrace_config *conf) override;
 281
 282   int disable_btrace (btrace_target_info *tinfo) override;
 283
 284   int read_btrace (btrace_target_info *tinfo, buffer *buf,
 285                    enum btrace_read_type type) override;
 286
 287   int read_btrace_conf (const btrace_target_info *tinfo,
 288                         buffer *buf) override;
 289 #endif
 290
 291   bool supports_range_stepping () override;
 292
 293   bool supports_pid_to_exec_file () override;
 294
 295   const char *pid_to_exec_file (int pid) override;
 296
 297   bool supports_multifs () override;
 298
 299   int multifs_open (int pid, const char *filename, int flags,
 300                     mode_t mode) override;
 301
 302   int multifs_unlink (int pid, const char *filename) override;
 303
 304   ssize_t multifs_readlink (int pid, const char *filename, char *buf,
 305                             size_t bufsiz) override;
 306
 307   const char *thread_name (ptid_t thread) override;
 308
 309 #if USE_THREAD_DB
 310   bool thread_handle (ptid_t ptid, gdb_byte **handle,
 311                       int *handle_len) override;
 312 #endif
 313
 314   bool supports_catch_syscall () override;
 315
 316   /* Return the information to access registers.  This has public
 317      visibility because proc-service uses it.  */
 318   virtual const regs_info *get_regs_info () = 0;
 319
 320 private:
 321
 322   /* Handle a GNU/Linux extended wait response.  If we see a clone,
 323      fork, or vfork event, we need to add the new LWP to our list
 324      (and return 0 so as not to report the trap to higher layers).
 325      If we see an exec event, we will modify ORIG_EVENT_LWP to point
 326      to a new LWP representing the new program.  */
 327   int handle_extended_wait (lwp_info **orig_event_lwp, int wstat);
 328
 329   /* Do low-level handling of the event, and check if this is an event we want
 330      to report.  Is so, store it as a pending status in the lwp_info structure
 331      corresponding to LWPID.  */
 332   void filter_event (int lwpid, int wstat);
 333
 334   /* Wait for an event from child(ren) WAIT_PTID, and return any that
 335      match FILTER_PTID (leaving others pending).  The PTIDs can be:
 336      minus_one_ptid, to specify any child; a pid PTID, specifying all
 337      lwps of a thread group; or a PTID representing a single lwp.  Store
 338      the stop status through the status pointer WSTAT.  OPTIONS is
 339      passed to the waitpid call.  Return 0 if no event was found and
 340      OPTIONS contains WNOHANG.  Return -1 if no unwaited-for children
 341      was found.  Return the PID of the stopped child otherwise.  */
 342   int wait_for_event_filtered (ptid_t wait_ptid, ptid_t filter_ptid,
 343                                int *wstatp, int options);
 344
 345   /* Wait for an event from child(ren) PTID.  PTIDs can be:
 346      minus_one_ptid, to specify any child; a pid PTID, specifying all
 347      lwps of a thread group; or a PTID representing a single lwp.  Store
 348      the stop status through the status pointer WSTAT.  OPTIONS is
 349      passed to the waitpid call.  Return 0 if no event was found and
 350      OPTIONS contains WNOHANG.  Return -1 if no unwaited-for children
 351      was found.  Return the PID of the stopped child otherwise.  */
 352   int wait_for_event (ptid_t ptid, int *wstatp, int options);
 353
 354   /* Wait for all children to stop for the SIGSTOPs we just queued.  */
 355   void wait_for_sigstop ();
 356
 357   /* Wait for process, returns status.  */
 358   ptid_t wait_1 (ptid_t ptid, target_waitstatus *ourstatus,
 359                  target_wait_flags target_options);
 360
 361   /* Stop all lwps that aren't stopped yet, except EXCEPT, if not NULL.
 362      If SUSPEND, then also increase the suspend count of every LWP,
 363      except EXCEPT.  */
 364   void stop_all_lwps (int suspend, lwp_info *except);
 365
 366   /* Stopped LWPs that the client wanted to be running, that don't have
 367      pending statuses, are set to run again, except for EXCEPT, if not
 368      NULL.  This undoes a stop_all_lwps call.  */
 369   void unstop_all_lwps (int unsuspend, lwp_info *except);
 370
 371   /* Start a step-over operation on LWP.  When LWP stopped at a
 372      breakpoint, to make progress, we need to remove the breakpoint out
 373      of the way.  If we let other threads run while we do that, they may
 374      pass by the breakpoint location and miss hitting it.  To avoid
 375      that, a step-over momentarily stops all threads while LWP is
 376      single-stepped by either hardware or software while the breakpoint
 377      is temporarily uninserted from the inferior.  When the single-step
 378      finishes, we reinsert the breakpoint, and let all threads that are
 379      supposed to be running, run again.  */
 380   void start_step_over (lwp_info *lwp);
 381
 382   /* If there's a step over in progress, wait until all threads stop
 383      (that is, until the stepping thread finishes its step), and
 384      unsuspend all lwps.  The stepping thread ends with its status
 385      pending, which is processed later when we get back to processing
 386      events.  */
 387   void complete_ongoing_step_over ();
 388
 389   /* Finish a step-over.  Reinsert the breakpoint we had uninserted in
 390      start_step_over, if still there, and delete any single-step
 391      breakpoints we've set, on non hardware single-step targets.
 392      Return true if step over finished.  */
 393   bool finish_step_over (lwp_info *lwp);
 394
 395   /* When we finish a step-over, set threads running again.  If there's
 396      another thread that may need a step-over, now's the time to start
 397      it.  Eventually, we'll move all threads past their breakpoints.  */
 398   void proceed_all_lwps ();
 399
 400   /* The reason we resume in the caller, is because we want to be able
 401      to pass lwp->status_pending as WSTAT, and we need to clear
 402      status_pending_p before resuming, otherwise, resume_one_lwp
 403      refuses to resume.  */
 404   bool maybe_move_out_of_jump_pad (lwp_info *lwp, int *wstat);
 405
 406   /* Move THREAD out of the jump pad.  */
 407   void move_out_of_jump_pad (thread_info *thread);
 408
 409   /* Call low_arch_setup on THREAD.  */
 410   void arch_setup_thread (thread_info *thread);
 411
 412 #ifdef HAVE_LINUX_USRREGS
 413   /* Fetch one register.  */
 414   void fetch_register (const usrregs_info *usrregs, regcache *regcache,
 415                        int regno);
 416
 417   /* Store one register.  */
 418   void store_register (const usrregs_info *usrregs, regcache *regcache,
 419                        int regno);
 420 #endif
 421
 422   /* Fetch all registers, or just one, from the child process.
 423      If REGNO is -1, do this for all registers, skipping any that are
 424      assumed to have been retrieved by regsets_fetch_inferior_registers,
 425      unless ALL is non-zero.
 426      Otherwise, REGNO specifies which register (so we can save time).  */
 427   void usr_fetch_inferior_registers (const regs_info *regs_info,
 428                                      regcache *regcache, int regno, int all);
 429
 430   /* Store our register values back into the inferior.
 431      If REGNO is -1, do this for all registers, skipping any that are
 432      assumed to have been saved by regsets_store_inferior_registers,
 433      unless ALL is non-zero.
 434      Otherwise, REGNO specifies which register (so we can save time).  */
 435   void usr_store_inferior_registers (const regs_info *regs_info,
 436                                      regcache *regcache, int regno, int all);
 437
 438   /* Return the PC as read from the regcache of LWP, without any
 439      adjustment.  */
 440   CORE_ADDR get_pc (lwp_info *lwp);
 441
 442   /* Called when the LWP stopped for a signal/trap.  If it stopped for a
 443      trap check what caused it (breakpoint, watchpoint, trace, etc.),
 444      and save the result in the LWP's stop_reason field.  If it stopped
 445      for a breakpoint, decrement the PC if necessary on the lwp's
 446      architecture.  Returns true if we now have the LWP's stop PC.  */
 447   bool save_stop_reason (lwp_info *lwp);
 448
 449   /* Resume execution of LWP.  If STEP is nonzero, single-step it.  If
 450      SIGNAL is nonzero, give it that signal.  */
 451   void resume_one_lwp_throw (lwp_info *lwp, int step, int signal,
 452                              siginfo_t *info);
 453
 454   /* Like resume_one_lwp_throw, but no error is thrown if the LWP
 455      disappears while we try to resume it.  */
 456   void resume_one_lwp (lwp_info *lwp, int step, int signal, siginfo_t *info);
 457
 458   /* This function is called once per thread.  We check the thread's
 459      last resume request, which will tell us whether to resume, step, or
 460      leave the thread stopped.  Any signal the client requested to be
 461      delivered has already been enqueued at this point.
 462
 463      If any thread that GDB wants running is stopped at an internal
 464      breakpoint that needs stepping over, we start a step-over operation
 465      on that particular thread, and leave all others stopped.  */
 466   void proceed_one_lwp (thread_info *thread, lwp_info *except);
 467
 468   /* This function is called once per thread.  We check the thread's
 469      resume request, which will tell us whether to resume, step, or
 470      leave the thread stopped; and what signal, if any, it should be
 471      sent.
 472
 473      For threads which we aren't explicitly told otherwise, we preserve
 474      the stepping flag; this is used for stepping over gdbserver-placed
 475      breakpoints.
 476
 477      If pending_flags was set in any thread, we queue any needed
 478      signals, since we won't actually resume.  We already have a pending
 479      event to report, so we don't need to preserve any step requests;
 480      they should be re-issued if necessary.  */
 481   void resume_one_thread (thread_info *thread, bool leave_all_stopped);
 482
 483   /* Return true if this lwp has an interesting status pending.  */
 484   bool status_pending_p_callback (thread_info *thread, ptid_t ptid);
 485
 486   /* Resume LWPs that are currently stopped without any pending status
 487      to report, but are resumed from the core's perspective.  */
 488   void resume_stopped_resumed_lwps (thread_info *thread);
 489
 490   /* Unsuspend THREAD, except EXCEPT, and proceed.  */
 491   void unsuspend_and_proceed_one_lwp (thread_info *thread, lwp_info *except);
 492
 493   /* Return true if this lwp still has an interesting status pending.
 494      If not (e.g., it had stopped for a breakpoint that is gone), return
 495      false.  */
 496   bool thread_still_has_status_pending (thread_info *thread);
 497
 498   /* Return true if this lwp is to-be-resumed and has an interesting
 499      status pending.  */
 500   bool resume_status_pending (thread_info *thread);
 501
 502   /* Return true if this lwp that GDB wants running is stopped at an
 503      internal breakpoint that we need to step over.  It assumes that
 504      any required STOP_PC adjustment has already been propagated to
 505      the inferior's regcache.  */
 506   bool thread_needs_step_over (thread_info *thread);
 507
 508   /* Single step via hardware or software single step.
 509      Return 1 if hardware single stepping, 0 if software single stepping
 510      or can't single step.  */
 511   int single_step (lwp_info* lwp);
 512
 513   /* Return true if THREAD is doing hardware single step.  */
 514   bool maybe_hw_step (thread_info *thread);
 515
 516   /* Install breakpoints for software single stepping.  */
 517   void install_software_single_step_breakpoints (lwp_info *lwp);
 518
 519   /* Fetch the possibly triggered data watchpoint info and store it in
 520      CHILD.
 521
 522      On some archs, like x86, that use debug registers to set
 523      watchpoints, it's possible that the way to know which watched
 524      address trapped, is to check the register that is used to select
 525      which address to watch.  Problem is, between setting the watchpoint
 526      and reading back which data address trapped, the user may change
 527      the set of watchpoints, and, as a consequence, GDB changes the
 528      debug registers in the inferior.  To avoid reading back a stale
 529      stopped-data-address when that happens, we cache in LP the fact
 530      that a watchpoint trapped, and the corresponding data address, as
 531      soon as we see CHILD stop with a SIGTRAP.  If GDB changes the debug
 532      registers meanwhile, we have the cached data we can rely on.  */
 533   bool check_stopped_by_watchpoint (lwp_info *child);
 534
 535   /* Convert a native/host siginfo object, into/from the siginfo in the
 536      layout of the inferiors' architecture.  */
 537   void siginfo_fixup (siginfo_t *siginfo, gdb_byte *inf_siginfo,
 538                       int direction);
 539
 540   /* Add a process to the common process list, and set its private
 541      data.  */
 542   process_info *add_linux_process (int pid, int attached);
 543
 544   /* Add a new thread.  */
 545   lwp_info *add_lwp (ptid_t ptid);
 546
 547   /* Delete a thread.  */
 548   void delete_lwp (lwp_info *lwp);
 549
 550 public: /* Make this public because it's used from outside.  */
 551   /* Attach to an inferior process.  Returns 0 on success, ERRNO on
 552      error.  */
 553   int attach_lwp (ptid_t ptid);
 554
 555 private: /* Back to private.  */
 556   /* Detach from LWP.  */
 557   void detach_one_lwp (lwp_info *lwp);
 558
 559   /* Detect zombie thread group leaders, and "exit" them.  We can't
 560      reap their exits until all other threads in the group have
 561      exited.  */
 562   void check_zombie_leaders ();
 563
 564   /* Convenience function that is called when the kernel reports an exit
 565      event.  This decides whether to report the event to GDB as a
 566      process exit event, a thread exit event, or to suppress the
 567      event.  */
 568   ptid_t filter_exit_event (lwp_info *event_child,
 569                             target_waitstatus *ourstatus);
 570
 571   /* Returns true if THREAD is stopped in a jump pad, and we can't
 572      move it out, because we need to report the stop event to GDB.  For
 573      example, if the user puts a breakpoint in the jump pad, it's
 574      because she wants to debug it.  */
 575   bool stuck_in_jump_pad (thread_info *thread);
 576
 577   /* Convenience wrapper.  Returns information about LWP's fast tracepoint
 578      collection status.  */
 579   fast_tpoint_collect_result linux_fast_tracepoint_collecting
 580     (lwp_info *lwp, fast_tpoint_collect_status *status);
 581
 582   /* This function should only be called if LWP got a SYSCALL_SIGTRAP.
 583      Fill *SYSNO with the syscall nr trapped.  */
 584   void get_syscall_trapinfo (lwp_info *lwp, int *sysno);
 585
 586   /* Returns true if GDB is interested in the event_child syscall.
 587      Only to be called when stopped reason is SYSCALL_SIGTRAP.  */
 588   bool gdb_catch_this_syscall (lwp_info *event_child);
 589
 590 protected:
 591   /* The architecture-specific "low" methods are listed below.  */
 592
 593   /* Architecture-specific setup for the current thread.  */
 594   virtual void low_arch_setup () = 0;
 595
 596   /* Return false if we can fetch/store the register, true if we cannot
 597      fetch/store the register.  */
 598   virtual bool low_cannot_fetch_register (int regno) = 0;
 599
 600   virtual bool low_cannot_store_register (int regno) = 0;
 601
 602   /* Hook to fetch a register in some non-standard way.  Used for
 603      example by backends that have read-only registers with hardcoded
 604      values (e.g., IA64's gr0/fr0/fr1).  Returns true if register
 605      REGNO was supplied, false if not, and we should fallback to the
 606      standard ptrace methods.  */
 607   virtual bool low_fetch_register (regcache *regcache, int regno);
 608
 609   /* Return true if breakpoints are supported.  Such targets must
 610      implement the GET_PC and SET_PC methods.  */
 611   virtual bool low_supports_breakpoints ();
 612
 613   virtual CORE_ADDR low_get_pc (regcache *regcache);
 614
 615   virtual void low_set_pc (regcache *regcache, CORE_ADDR newpc);
 616
 617   /* Find the next possible PCs after the current instruction executes.
 618      Targets that override this method should also override
 619      'supports_software_single_step' to return true.  */
 620   virtual std::vector<CORE_ADDR> low_get_next_pcs (regcache *regcache);
 621
 622   /* Return true if there is a breakpoint at PC.  */
 623   virtual bool low_breakpoint_at (CORE_ADDR pc) = 0;
 624
 625   /* Breakpoint and watchpoint related functions.  See target.h for
 626      comments.  */
 627   virtual int low_insert_point (raw_bkpt_type type, CORE_ADDR addr,
 628                                 int size, raw_breakpoint *bp);
 629
 630   virtual int low_remove_point (raw_bkpt_type type, CORE_ADDR addr,
 631                                 int size, raw_breakpoint *bp);
 632
 633   virtual bool low_stopped_by_watchpoint ();
 634
 635   virtual CORE_ADDR low_stopped_data_address ();
 636
 637   /* Hooks to reformat register data for PEEKUSR/POKEUSR (in particular
 638      for registers smaller than an xfer unit).  */
 639   virtual void low_collect_ptrace_register (regcache *regcache, int regno,
 640                                             char *buf);
 641
 642   virtual void low_supply_ptrace_register (regcache *regcache, int regno,
 643                                            const char *buf);
 644
 645   /* Hook to convert from target format to ptrace format and back.
 646      Returns true if any conversion was done; false otherwise.
 647      If DIRECTION is 1, then copy from INF to NATIVE.
 648      If DIRECTION is 0, copy from NATIVE to INF.  */
 649   virtual bool low_siginfo_fixup (siginfo_t *native, gdb_byte *inf,
 650                                   int direction);
 651
 652   /* Hook to call when a new process is created or attached to.
 653      If extra per-process architecture-specific data is needed,
 654      allocate it here.  */
 655   virtual arch_process_info *low_new_process ();
 656
 657   /* Hook to call when a process is being deleted.  If extra per-process
 658      architecture-specific data is needed, delete it here.  */
 659   virtual void low_delete_process (arch_process_info *info);
 660
 661   /* Hook to call when a new thread is detected.
 662      If extra per-thread architecture-specific data is needed,
 663      allocate it here.  */
 664   virtual void low_new_thread (lwp_info *);
 665
 666   /* Hook to call when a thread is being deleted.  If extra per-thread
 667      architecture-specific data is needed, delete it here.  */
 668   virtual void low_delete_thread (arch_lwp_info *);
 669
 670   /* Hook to call, if any, when a new fork is attached.  */
 671   virtual void low_new_fork (process_info *parent, process_info *child);
 672
 673   /* Hook to call prior to resuming a thread.  */
 674   virtual void low_prepare_to_resume (lwp_info *lwp);
 675
 676   /* Fill ADDRP with the thread area address of LWPID.  Returns 0 on
 677      success, -1 on failure.  */
 678   virtual int low_get_thread_area (int lwpid, CORE_ADDR *addrp);
 679
 680   /* Returns true if the low target supports range stepping.  */
 681   virtual bool low_supports_range_stepping ();
 682
 683   /* Return true if the target supports catch syscall.  Such targets
 684      override the low_get_syscall_trapinfo method below.  */
 685   virtual bool low_supports_catch_syscall ();
 686
 687   /* Fill *SYSNO with the syscall nr trapped.  Only to be called when
 688      inferior is stopped due to SYSCALL_SIGTRAP.  */
 689   virtual void low_get_syscall_trapinfo (regcache *regcache, int *sysno);
 690
 691   /* How many bytes the PC should be decremented after a break.  */
 692   virtual int low_decr_pc_after_break ();
 693 };
 694
 695 extern linux_process_target *the_linux_target;
 696
 697 #define get_thread_lwp(thr) ((struct lwp_info *) (thread_target_data (thr)))
 698 #define get_lwp_thread(lwp) ((lwp)->thread)
 699
 700 /* Information about a signal that is to be delivered to a thread.  */
 701
 702 struct pending_signal
 703 {
 704   pending_signal (int signal)
 705     : signal {signal}
 706   {};
 707
 708   int signal;
 709   siginfo_t info;
 710 };
 711
 712 /* This struct is recorded in the target_data field of struct thread_info.
 713
 714    On linux ``all_threads'' is keyed by the LWP ID, which we use as the
 715    GDB protocol representation of the thread ID.  Threads also have
 716    a "process ID" (poorly named) which is (presently) the same as the
 717    LWP ID.
 718
 719    There is also ``all_processes'' is keyed by the "overall process ID",
 720    which GNU/Linux calls tgid, "thread group ID".  */
 721
 722 struct lwp_info
 723 {
 724   lwp_info ()
 725   {
 726     this->waitstatus.kind = TARGET_WAITKIND_IGNORE;
 727   }
 728
 729   /* Backlink to the parent object.  */
 730   struct thread_info *thread = nullptr;
 731
 732   /* If this flag is set, the next SIGSTOP will be ignored (the
 733      process will be immediately resumed).  This means that either we
 734      sent the SIGSTOP to it ourselves and got some other pending event
 735      (so the SIGSTOP is still pending), or that we stopped the
 736      inferior implicitly via PTRACE_ATTACH and have not waited for it
 737      yet.  */
 738   int stop_expected = 0;
 739
 740   /* When this is true, we shall not try to resume this thread, even
 741      if last_resume_kind isn't resume_stop.  */
 742   int suspended = 0;
 743
 744   /* If this flag is set, the lwp is known to be stopped right now (stop
 745      event already received in a wait()).  */
 746   int stopped = 0;
 747
 748   /* Signal whether we are in a SYSCALL_ENTRY or
 749      in a SYSCALL_RETURN event.
 750      Values:
 751      - TARGET_WAITKIND_SYSCALL_ENTRY
 752      - TARGET_WAITKIND_SYSCALL_RETURN */
 753   enum target_waitkind syscall_state = TARGET_WAITKIND_SYSCALL_ENTRY;
 754
 755   /* When stopped is set, the last wait status recorded for this lwp.  */
 756   int last_status = 0;
 757
 758   /* If WAITSTATUS->KIND != TARGET_WAITKIND_IGNORE, the waitstatus for
 759      this LWP's last event, to pass to GDB without any further
 760      processing.  This is used to store extended ptrace event
 761      information or exit status until it can be reported to GDB.  */
 762   struct target_waitstatus waitstatus;
 763
 764   /* When stopped is set, this is where the lwp last stopped, with
 765      decr_pc_after_break already accounted for.  If the LWP is
 766      running, this is the address at which the lwp was resumed.  */
 767   CORE_ADDR stop_pc = 0;
 768
 769   /* If this flag is set, STATUS_PENDING is a waitstatus that has not yet
 770      been reported.  */
 771   int status_pending_p = 0;
 772   int status_pending = 0;
 773
 774   /* The reason the LWP last stopped, if we need to track it
 775      (breakpoint, watchpoint, etc.)  */
 776   enum target_stop_reason stop_reason = TARGET_STOPPED_BY_NO_REASON;
 777
 778   /* On architectures where it is possible to know the data address of
 779      a triggered watchpoint, STOPPED_DATA_ADDRESS is non-zero, and
 780      contains such data address.  Only valid if STOPPED_BY_WATCHPOINT
 781      is true.  */
 782   CORE_ADDR stopped_data_address = 0;
 783
 784   /* If this is non-zero, it is a breakpoint to be reinserted at our next
 785      stop (SIGTRAP stops only).  */
 786   CORE_ADDR bp_reinsert = 0;
 787
 788   /* If this flag is set, the last continue operation at the ptrace
 789      level on this process was a single-step.  */
 790   int stepping = 0;
 791
 792   /* Range to single step within.  This is a copy of the step range
 793      passed along the last resume request.  See 'struct
 794      thread_resume'.  */
 795   CORE_ADDR step_range_start = 0; /* Inclusive */
 796   CORE_ADDR step_range_end = 0; /* Exclusive */
 797
 798   /* If this flag is set, we need to set the event request flags the
 799      next time we see this LWP stop.  */
 800   int must_set_ptrace_flags = 0;
 801
 802   /* A chain of signals that need to be delivered to this process.  */
 803   std::list<pending_signal> pending_signals;
 804
 805   /* A link used when resuming.  It is initialized from the resume request,
 806      and then processed and cleared in linux_resume_one_lwp.  */
 807   struct thread_resume *resume = nullptr;
 808
 809   /* Information bout this lwp's fast tracepoint collection status (is it
 810      currently stopped in the jump pad, and if so, before or at/after the
 811      relocated instruction).  Normally, we won't care about this, but we will
 812      if a signal arrives to this lwp while it is collecting.  */
 813   fast_tpoint_collect_result collecting_fast_tracepoint
 814     = fast_tpoint_collect_result::not_collecting;
 815
 816   /* A chain of signals that need to be reported to GDB.  These were
 817      deferred because the thread was doing a fast tracepoint collect
 818      when they arrived.  */
 819   std::list<pending_signal> pending_signals_to_report;
 820
 821   /* When collecting_fast_tracepoint is first found to be 1, we insert
 822      a exit-jump-pad-quickly breakpoint.  This is it.  */
 823   struct breakpoint *exit_jump_pad_bkpt = nullptr;
 824
 825 #ifdef USE_THREAD_DB
 826   int thread_known = 0;
 827   /* The thread handle, used for e.g. TLS access.  Only valid if
 828      THREAD_KNOWN is set.  */
 829   td_thrhandle_t th {};
 830
 831   /* The pthread_t handle.  */
 832   thread_t thread_handle {};
 833 #endif
 834
 835   /* Arch-specific additions.  */
 836   struct arch_lwp_info *arch_private = nullptr;
 837 };
 838
 839 int linux_pid_exe_is_elf_64_file (int pid, unsigned int *machine);
 840
 841 /* Attach to PTID.  Returns 0 on success, non-zero otherwise (an
 842    errno).  */
 843 int linux_attach_lwp (ptid_t ptid);
 844
 845 struct lwp_info *find_lwp_pid (ptid_t ptid);
 846 /* For linux_stop_lwp see nat/linux-nat.h.  */
 847
 848 #ifdef HAVE_LINUX_REGSETS
 849 void initialize_regsets_info (struct regsets_info *regsets_info);
 850 #endif
 851
 852 void initialize_low_arch (void);
 853
 854 void linux_set_pc_32bit (struct regcache *regcache, CORE_ADDR pc);
 855 CORE_ADDR linux_get_pc_32bit (struct regcache *regcache);
 856
 857 void linux_set_pc_64bit (struct regcache *regcache, CORE_ADDR pc);
 858 CORE_ADDR linux_get_pc_64bit (struct regcache *regcache);
 859
 860 /* From thread-db.c  */
 861 int thread_db_init (void);
 862 void thread_db_detach (struct process_info *);
 863 void thread_db_mourn (struct process_info *);
 864 int thread_db_handle_monitor_command (char *);
 865 int thread_db_get_tls_address (struct thread_info *thread, CORE_ADDR offset,
 866                                CORE_ADDR load_module, CORE_ADDR *address);
 867 int thread_db_look_up_one_symbol (const char *name, CORE_ADDR *addrp);
 868
 869 /* Called from linux-low.c when a clone event is detected.  Upon entry,
 870    both the clone and the parent should be stopped.  This function does
 871    whatever is required have the clone under thread_db's control.  */
 872
 873 void thread_db_notice_clone (struct thread_info *parent_thr, ptid_t child_ptid);
 874
 875 bool thread_db_thread_handle (ptid_t ptid, gdb_byte **handle, int *handle_len);
 876
 877 extern int have_ptrace_getregset;
 878
 879 /* Search for the value with type MATCH in the auxv vector with
 880    entries of length WORDSIZE bytes.  If found, store the value in
 881    *VALP and return 1.  If not found or if there is an error, return
 882    0.  */
 883
 884 int linux_get_auxv (int wordsize, CORE_ADDR match,
 885                     CORE_ADDR *valp);
 886
 887 /* Fetch the AT_HWCAP entry from the auxv vector, where entries are length
 888    WORDSIZE.  If no entry was found, return zero.  */
 889
 890 CORE_ADDR linux_get_hwcap (int wordsize);
 891
 892 /* Fetch the AT_HWCAP2 entry from the auxv vector, where entries are length
 893    WORDSIZE.  If no entry was found, return zero.  */
 894
 895 CORE_ADDR linux_get_hwcap2 (int wordsize);
 896
 897 #endif /* GDBSERVER_LINUX_LOW_H */