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