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