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