gdbserver/linux-low.h

   1 /* Internal interfaces for the GNU/Linux specific target code for gdbserver.
   2    Copyright (C) 2002-2022 Free Software Foundation, Inc.
   3
   4    This file is part of GDB.
   5
   6    This program is free software; you can redistribute it and/or modify
   7    it under the terms of the GNU General Public License as published by
   8    the Free Software Foundation; either version 3 of the License, or
   9    (at your option) any later version.
  10
  11    This program is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14    GNU General Public License for more details.
  15
  16    You should have received a copy of the GNU General Public License
  17    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
  18
  19 #ifndef GDBSERVER_LINUX_LOW_H
  20 #define GDBSERVER_LINUX_LOW_H
  21
  22 #include "nat/linux-nat.h"
  23 #include "nat/gdb_thread_db.h"
  24 #include <signal.h>
  25
  26 #include "gdbthread.h"
  27 #include "gdb_proc_service.h"
  28
  29 /* Included for ptrace type definitions.  */
  30 #include "nat/linux-ptrace.h"
  31 #include "target/waitstatus.h" /* For enum target_stop_reason.  */
  32 #include "tracepoint.h"
  33
  34 #include <list>
  35
  36 #define PTRACE_XFER_TYPE long
  37
  38 #ifdef HAVE_LINUX_REGSETS
  39 typedef void (*regset_fill_func) (struct regcache *, void *);
  40 typedef void (*regset_store_func) (struct regcache *, const void *);
  41 enum regset_type {
  42   GENERAL_REGS,
  43   FP_REGS,
  44   EXTENDED_REGS,
  45   OPTIONAL_REGS, /* Do not error if the regset cannot be accessed.  */
  46 };
  47
  48 /* The arch's regsets array initializer must be terminated with a NULL
  49    regset.  */
  50 #define NULL_REGSET \
  51   { 0, 0, 0, -1, (enum regset_type) -1, NULL, NULL }
  52
  53 struct regset_info
  54 {
  55   int get_request, set_request;
  56   /* If NT_TYPE isn't 0, it will be passed to ptrace as the 3rd
  57      argument and the 4th argument should be "const struct iovec *".  */
  58   int nt_type;
  59   int size;
  60   enum regset_type type;
  61   regset_fill_func fill_function;
  62   regset_store_func store_function;
  63 };
  64
  65 /* Aggregation of all the supported regsets of a given
  66    architecture/mode.  */
  67
  68 struct regsets_info
  69 {
  70   /* The regsets array.  */
  71   struct regset_info *regsets;
  72
  73   /* The number of regsets in the REGSETS array.  */
  74   int num_regsets;
  75
  76   /* If we get EIO on a regset, do not try it again.  Note the set of
  77      supported regsets may depend on processor mode on biarch
  78      machines.  This is a (lazily allocated) array holding one boolean
  79      byte (0/1) per regset, with each element corresponding to the
  80      regset in the REGSETS array above at the same offset.  */
  81   char *disabled_regsets;
  82 };
  83
  84 #endif
  85
  86 /* Mapping between the general-purpose registers in `struct user'
  87    format and GDB's register array layout.  */
  88
  89 struct usrregs_info
  90 {
  91   /* The number of registers accessible.  */
  92   int num_regs;
  93
  94   /* The registers map.  */
  95   int *regmap;
  96 };
  97
  98 /* All info needed to access an architecture/mode's registers.  */
  99
 100 struct regs_info
 101 {
 102   /* Regset support bitmap: 1 for registers that are transferred as a part
 103      of a regset, 0 for ones that need to be handled individually.  This
 104      can be NULL if all registers are transferred with regsets or regsets
 105      are not supported.  */
 106   unsigned char *regset_bitmap;
 107
 108   /* Info used when accessing registers with PTRACE_PEEKUSER /
 109      PTRACE_POKEUSER.  This can be NULL if all registers are
 110      transferred with regsets  .*/
 111   struct usrregs_info *usrregs;
 112
 113 #ifdef HAVE_LINUX_REGSETS
 114   /* Info used when accessing registers with regsets.  */
 115   struct regsets_info *regsets_info;
 116 #endif
 117 };
 118
 119 struct process_info_private
 120 {
 121   /* Arch-specific additions.  */
 122   struct arch_process_info *arch_private;
 123
 124   /* libthread_db-specific additions.  Not NULL if this process has loaded
 125      thread_db, and it is active.  */
 126   struct thread_db *thread_db;
 127
 128   /* &_r_debug.  0 if not yet determined.  -1 if no PT_DYNAMIC in Phdrs.  */
 129   CORE_ADDR r_debug;
 130 };
 131
 132 struct lwp_info;
 133
 134 /* Target ops definitions for a Linux target.  */
 135
 136 class linux_process_target : public process_stratum_target
 137 {
 138 public:
 139
 140   int create_inferior (const char *program,
 141                        const std::vector<char *> &program_args) override;
 142
 143   void post_create_inferior () override;
 144
 145   int attach (unsigned long pid) override;
 146
 147   int kill (process_info *proc) override;
 148
 149   int detach (process_info *proc) override;
 150
 151   void mourn (process_info *proc) override;
 152
 153   void join (int pid) override;
 154
 155   bool thread_alive (ptid_t pid) override;
 156
 157   void resume (thread_resume *resume_info, size_t n) override;
 158
 159   ptid_t wait (ptid_t ptid, target_waitstatus *status,
 160                target_wait_flags options) override;
 161
 162   void fetch_registers (regcache *regcache, int regno) override;
 163
 164   void store_registers (regcache *regcache, int regno) override;
 165
 166   int prepare_to_access_memory () override;
 167
 168   void done_accessing_memory () override;
 169
 170   int read_memory (CORE_ADDR memaddr, unsigned char *myaddr,
 171                    int len) override;
 172
 173   int write_memory (CORE_ADDR memaddr, const unsigned char *myaddr,
 174                     int len) override;
 175
 176   void look_up_symbols () override;
 177
 178   void request_interrupt () override;
 179
 180   bool supports_read_auxv () override;
 181
 182   int read_auxv (CORE_ADDR offset, unsigned char *myaddr,
 183                  unsigned int len) override;
 184
 185   int insert_point (enum raw_bkpt_type type, CORE_ADDR addr,
 186                     int size, raw_breakpoint *bp) override;
 187
 188   int remove_point (enum raw_bkpt_type type, CORE_ADDR addr,
 189                     int size, raw_breakpoint *bp) override;
 190
 191   bool stopped_by_sw_breakpoint () override;
 192
 193   bool supports_stopped_by_sw_breakpoint () override;
 194
 195   bool stopped_by_hw_breakpoint () override;
 196
 197   bool supports_stopped_by_hw_breakpoint () override;
 198
 199   bool supports_hardware_single_step () override;
 200
 201   bool stopped_by_watchpoint () override;
 202
 203   CORE_ADDR stopped_data_address () override;
 204
 205   bool supports_read_offsets () override;
 206
 207   int read_offsets (CORE_ADDR *text, CORE_ADDR *data) override;
 208
 209   bool supports_get_tls_address () override;
 210
 211   int get_tls_address (thread_info *thread, CORE_ADDR offset,
 212                        CORE_ADDR load_module, CORE_ADDR *address) override;
 213
 214   bool supports_qxfer_osdata () override;
 215
 216   int qxfer_osdata (const char *annex, unsigned char *readbuf,
 217                     unsigned const char *writebuf,
 218                     CORE_ADDR offset, int len) override;
 219
 220   bool supports_qxfer_siginfo () override;
 221
 222   int qxfer_siginfo (const char *annex, unsigned char *readbuf,
 223                      unsigned const char *writebuf,
 224                      CORE_ADDR offset, int len) override;
 225
 226   bool supports_non_stop () override;
 227
 228   bool async (bool enable) override;
 229
 230   int start_non_stop (bool enable) override;
 231
 232   bool supports_multi_process () override;
 233
 234   bool supports_fork_events () override;
 235
 236   bool supports_vfork_events () override;
 237
 238   bool supports_exec_events () override;
 239
 240   void handle_new_gdb_connection () override;
 241
 242   int handle_monitor_command (char *mon) override;
 243
 244   int core_of_thread (ptid_t ptid) override;
 245
 246 #if defined PT_GETDSBT || defined PTRACE_GETFDPIC
 247   bool supports_read_loadmap () override;
 248
 249   int read_loadmap (const char *annex, CORE_ADDR offset,
 250                     unsigned char *myaddr, unsigned int len) override;
 251 #endif
 252
 253   CORE_ADDR read_pc (regcache *regcache) override;
 254
 255   void write_pc (regcache *regcache, CORE_ADDR pc) override;
 256
 257   bool supports_thread_stopped () override;
 258
 259   bool thread_stopped (thread_info *thread) override;
 260
 261   void pause_all (bool freeze) override;
 262
 263   void unpause_all (bool unfreeze) override;
 264
 265   void stabilize_threads () override;
 266
 267   bool supports_disable_randomization () override;
 268
 269   bool supports_qxfer_libraries_svr4 () override;
 270
 271   int qxfer_libraries_svr4 (const char *annex,
 272                             unsigned char *readbuf,
 273                             unsigned const char *writebuf,
 274                             CORE_ADDR offset, int len) override;
 275
 276   bool supports_agent () override;
 277
 278 #ifdef HAVE_LINUX_BTRACE
 279   btrace_target_info *enable_btrace (ptid_t ptid,
 280                                      const btrace_config *conf) override;
 281
 282   int disable_btrace (btrace_target_info *tinfo) override;
 283
 284   int read_btrace (btrace_target_info *tinfo, buffer *buf,
 285                    enum btrace_read_type type) override;
 286
 287   int read_btrace_conf (const btrace_target_info *tinfo,
 288                         buffer *buf) override;
 289 #endif
 290
 291   bool supports_range_stepping () override;
 292
 293   bool supports_pid_to_exec_file () override;
 294
 295   const char *pid_to_exec_file (int pid) override;
 296
 297   bool supports_multifs () override;
 298
 299   int multifs_open (int pid, const char *filename, int flags,
 300                     mode_t mode) override;
 301
 302   int multifs_unlink (int pid, const char *filename) override;
 303
 304   ssize_t multifs_readlink (int pid, const char *filename, char *buf,
 305                             size_t bufsiz) override;
 306
 307   const char *thread_name (ptid_t thread) override;
 308
 309 #if USE_THREAD_DB
 310   bool thread_handle (ptid_t ptid, gdb_byte **handle,
 311                       int *handle_len) override;
 312 #endif
 313
 314   thread_info *thread_pending_parent (thread_info *thread) override;
 315
 316   bool supports_catch_syscall () override;
 317
 318   /* Return the information to access registers.  This has public
 319      visibility because proc-service uses it.  */
 320   virtual const regs_info *get_regs_info () = 0;
 321
 322 private:
 323
 324   /* Handle a GNU/Linux extended wait response.  If we see a clone,
 325      fork, or vfork event, we need to add the new LWP to our list
 326      (and return 0 so as not to report the trap to higher layers).
 327      If we see an exec event, we will modify ORIG_EVENT_LWP to point
 328      to a new LWP representing the new program.  */
 329   int handle_extended_wait (lwp_info **orig_event_lwp, int wstat);
 330
 331   /* Do low-level handling of the event, and check if this is an event we want
 332      to report.  Is so, store it as a pending status in the lwp_info structure
 333      corresponding to LWPID.  */
 334   void filter_event (int lwpid, int wstat);
 335
 336   /* Wait for an event from child(ren) WAIT_PTID, and return any that
 337      match FILTER_PTID (leaving others pending).  The PTIDs can be:
 338      minus_one_ptid, to specify any child; a pid PTID, specifying all
 339      lwps of a thread group; or a PTID representing a single lwp.  Store
 340      the stop status through the status pointer WSTAT.  OPTIONS is
 341      passed to the waitpid call.  Return 0 if no event was found and
 342      OPTIONS contains WNOHANG.  Return -1 if no unwaited-for children
 343      was found.  Return the PID of the stopped child otherwise.  */
 344   int wait_for_event_filtered (ptid_t wait_ptid, ptid_t filter_ptid,
 345                                int *wstatp, int options);
 346
 347   /* Wait for an event from child(ren) PTID.  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 (ptid_t ptid, int *wstatp, int options);
 355
 356   /* Wait for all children to stop for the SIGSTOPs we just queued.  */
 357   void wait_for_sigstop ();
 358
 359   /* Wait for process, returns status.  */
 360   ptid_t wait_1 (ptid_t ptid, target_waitstatus *ourstatus,
 361                  target_wait_flags target_options);
 362
 363   /* Stop all lwps that aren't stopped yet, except EXCEPT, if not NULL.
 364      If SUSPEND, then also increase the suspend count of every LWP,
 365      except EXCEPT.  */
 366   void stop_all_lwps (int suspend, lwp_info *except);
 367
 368   /* Stopped LWPs that the client wanted to be running, that don't have
 369      pending statuses, are set to run again, except for EXCEPT, if not
 370      NULL.  This undoes a stop_all_lwps call.  */
 371   void unstop_all_lwps (int unsuspend, lwp_info *except);
 372
 373   /* Start a step-over operation on LWP.  When LWP stopped at a
 374      breakpoint, to make progress, we need to remove the breakpoint out
 375      of the way.  If we let other threads run while we do that, they may
 376      pass by the breakpoint location and miss hitting it.  To avoid
 377      that, a step-over momentarily stops all threads while LWP is
 378      single-stepped by either hardware or software while the breakpoint
 379      is temporarily uninserted from the inferior.  When the single-step
 380      finishes, we reinsert the breakpoint, and let all threads that are
 381      supposed to be running, run again.  */
 382   void start_step_over (lwp_info *lwp);
 383
 384   /* If there's a step over in progress, wait until all threads stop
 385      (that is, until the stepping thread finishes its step), and
 386      unsuspend all lwps.  The stepping thread ends with its status
 387      pending, which is processed later when we get back to processing
 388      events.  */
 389   void complete_ongoing_step_over ();
 390
 391   /* Finish a step-over.  Reinsert the breakpoint we had uninserted in
 392      start_step_over, if still there, and delete any single-step
 393      breakpoints we've set, on non hardware single-step targets.
 394      Return true if step over finished.  */
 395   bool finish_step_over (lwp_info *lwp);
 396
 397   /* When we finish a step-over, set threads running again.  If there's
 398      another thread that may need a step-over, now's the time to start
 399      it.  Eventually, we'll move all threads past their breakpoints.  */
 400   void proceed_all_lwps ();
 401
 402   /* The reason we resume in the caller, is because we want to be able
 403      to pass lwp->status_pending as WSTAT, and we need to clear
 404      status_pending_p before resuming, otherwise, resume_one_lwp
 405      refuses to resume.  */
 406   bool maybe_move_out_of_jump_pad (lwp_info *lwp, int *wstat);
 407
 408   /* Move THREAD out of the jump pad.  */
 409   void move_out_of_jump_pad (thread_info *thread);
 410
 411   /* Call low_arch_setup on THREAD.  */
 412   void arch_setup_thread (thread_info *thread);
 413
 414 #ifdef HAVE_LINUX_USRREGS
 415   /* Fetch one register.  */
 416   void fetch_register (const usrregs_info *usrregs, regcache *regcache,
 417                        int regno);
 418
 419   /* Store one register.  */
 420   void store_register (const usrregs_info *usrregs, regcache *regcache,
 421                        int regno);
 422 #endif
 423
 424   /* Fetch all registers, or just one, from the child process.
 425      If REGNO is -1, do this for all registers, skipping any that are
 426      assumed to have been retrieved by regsets_fetch_inferior_registers,
 427      unless ALL is non-zero.
 428      Otherwise, REGNO specifies which register (so we can save time).  */
 429   void usr_fetch_inferior_registers (const regs_info *regs_info,
 430                                      regcache *regcache, int regno, int all);
 431
 432   /* Store our register values back into the inferior.
 433      If REGNO is -1, do this for all registers, skipping any that are
 434      assumed to have been saved by regsets_store_inferior_registers,
 435      unless ALL is non-zero.
 436      Otherwise, REGNO specifies which register (so we can save time).  */
 437   void usr_store_inferior_registers (const regs_info *regs_info,
 438                                      regcache *regcache, int regno, int all);
 439
 440   /* Return the PC as read from the regcache of LWP, without any
 441      adjustment.  */
 442   CORE_ADDR get_pc (lwp_info *lwp);
 443
 444   /* Called when the LWP stopped for a signal/trap.  If it stopped for a
 445      trap check what caused it (breakpoint, watchpoint, trace, etc.),
 446      and save the result in the LWP's stop_reason field.  If it stopped
 447      for a breakpoint, decrement the PC if necessary on the lwp's
 448      architecture.  Returns true if we now have the LWP's stop PC.  */
 449   bool save_stop_reason (lwp_info *lwp);
 450
 451   /* Resume execution of LWP.  If STEP is nonzero, single-step it.  If
 452      SIGNAL is nonzero, give it that signal.  */
 453   void resume_one_lwp_throw (lwp_info *lwp, int step, int signal,
 454                              siginfo_t *info);
 455
 456   /* Like resume_one_lwp_throw, but no error is thrown if the LWP
 457      disappears while we try to resume it.  */
 458   void resume_one_lwp (lwp_info *lwp, int step, int signal, siginfo_t *info);
 459
 460   /* This function is called once per thread.  We check the thread's
 461      last resume request, which will tell us whether to resume, step, or
 462      leave the thread stopped.  Any signal the client requested to be
 463      delivered has already been enqueued at this point.
 464
 465      If any thread that GDB wants running is stopped at an internal
 466      breakpoint that needs stepping over, we start a step-over operation
 467      on that particular thread, and leave all others stopped.  */
 468   void proceed_one_lwp (thread_info *thread, lwp_info *except);
 469
 470   /* This function is called once per thread.  We check the thread's
 471      resume request, which will tell us whether to resume, step, or
 472      leave the thread stopped; and what signal, if any, it should be
 473      sent.
 474
 475      For threads which we aren't explicitly told otherwise, we preserve
 476      the stepping flag; this is used for stepping over gdbserver-placed
 477      breakpoints.
 478
 479      If pending_flags was set in any thread, we queue any needed
 480      signals, since we won't actually resume.  We already have a pending
 481      event to report, so we don't need to preserve any step requests;
 482      they should be re-issued if necessary.  */
 483   void resume_one_thread (thread_info *thread, bool leave_all_stopped);
 484
 485   /* Return true if this lwp has an interesting status pending.  */
 486   bool status_pending_p_callback (thread_info *thread, ptid_t ptid);
 487
 488   /* Resume LWPs that are currently stopped without any pending status
 489      to report, but are resumed from the core's perspective.  */
 490   void resume_stopped_resumed_lwps (thread_info *thread);
 491
 492   /* Unsuspend THREAD, except EXCEPT, and proceed.  */
 493   void unsuspend_and_proceed_one_lwp (thread_info *thread, lwp_info *except);
 494
 495   /* Return true if this lwp still has an interesting status pending.
 496      If not (e.g., it had stopped for a breakpoint that is gone), return
 497      false.  */
 498   bool thread_still_has_status_pending (thread_info *thread);
 499
 500   /* Return true if this lwp is to-be-resumed and has an interesting
 501      status pending.  */
 502   bool resume_status_pending (thread_info *thread);
 503
 504   /* Return true if this lwp that GDB wants running is stopped at an
 505      internal breakpoint that we need to step over.  It assumes that
 506      any required STOP_PC adjustment has already been propagated to
 507      the inferior's regcache.  */
 508   bool thread_needs_step_over (thread_info *thread);
 509
 510   /* Single step via hardware or software single step.
 511      Return 1 if hardware single stepping, 0 if software single stepping
 512      or can't single step.  */
 513   int single_step (lwp_info* lwp);
 514
 515   /* Return true if THREAD is doing hardware single step.  */
 516   bool maybe_hw_step (thread_info *thread);
 517
 518   /* Install breakpoints for software single stepping.  */
 519   void install_software_single_step_breakpoints (lwp_info *lwp);
 520
 521   /* Fetch the possibly triggered data watchpoint info and store it in
 522      CHILD.
 523
 524      On some archs, like x86, that use debug registers to set
 525      watchpoints, it's possible that the way to know which watched
 526      address trapped, is to check the register that is used to select
 527      which address to watch.  Problem is, between setting the watchpoint
 528      and reading back which data address trapped, the user may change
 529      the set of watchpoints, and, as a consequence, GDB changes the
 530      debug registers in the inferior.  To avoid reading back a stale
 531      stopped-data-address when that happens, we cache in LP the fact
 532      that a watchpoint trapped, and the corresponding data address, as
 533      soon as we see CHILD stop with a SIGTRAP.  If GDB changes the debug
 534      registers meanwhile, we have the cached data we can rely on.  */
 535   bool check_stopped_by_watchpoint (lwp_info *child);
 536
 537   /* Convert a native/host siginfo object, into/from the siginfo in the
 538      layout of the inferiors' architecture.  */
 539   void siginfo_fixup (siginfo_t *siginfo, gdb_byte *inf_siginfo,
 540                       int direction);
 541
 542   /* Add a process to the common process list, and set its private
 543      data.  */
 544   process_info *add_linux_process (int pid, int attached);
 545
 546   /* Add a new thread.  */
 547   lwp_info *add_lwp (ptid_t ptid);
 548
 549   /* Delete a thread.  */
 550   void delete_lwp (lwp_info *lwp);
 551
 552 public: /* Make this public because it's used from outside.  */
 553   /* Attach to an inferior process.  Returns 0 on success, ERRNO on
 554      error.  */
 555   int attach_lwp (ptid_t ptid);
 556
 557 private: /* Back to private.  */
 558   /* Detach from LWP.  */
 559   void detach_one_lwp (lwp_info *lwp);
 560
 561   /* Detect zombie thread group leaders, and "exit" them.  We can't
 562      reap their exits until all other threads in the group have
 563      exited.  */
 564   void check_zombie_leaders ();
 565
 566   /* Convenience function that is called when the kernel reports an exit
 567      event.  This decides whether to report the event to GDB as a
 568      process exit event, a thread exit event, or to suppress the
 569      event.  */
 570   ptid_t filter_exit_event (lwp_info *event_child,
 571                             target_waitstatus *ourstatus);
 572
 573   /* Returns true if THREAD is stopped in a jump pad, and we can't
 574      move it out, because we need to report the stop event to GDB.  For
 575      example, if the user puts a breakpoint in the jump pad, it's
 576      because she wants to debug it.  */
 577   bool stuck_in_jump_pad (thread_info *thread);
 578
 579   /* Convenience wrapper.  Returns information about LWP's fast tracepoint
 580      collection status.  */
 581   fast_tpoint_collect_result linux_fast_tracepoint_collecting
 582     (lwp_info *lwp, fast_tpoint_collect_status *status);
 583
 584   /* This function should only be called if LWP got a SYSCALL_SIGTRAP.
 585      Fill *SYSNO with the syscall nr trapped.  */
 586   void get_syscall_trapinfo (lwp_info *lwp, int *sysno);
 587
 588   /* Returns true if GDB is interested in the event_child syscall.
 589      Only to be called when stopped reason is SYSCALL_SIGTRAP.  */
 590   bool gdb_catch_this_syscall (lwp_info *event_child);
 591
 592 protected:
 593   /* The architecture-specific "low" methods are listed below.  */
 594
 595   /* Architecture-specific setup for the current thread.  */
 596   virtual void low_arch_setup () = 0;
 597
 598   /* Return false if we can fetch/store the register, true if we cannot
 599      fetch/store the register.  */
 600   virtual bool low_cannot_fetch_register (int regno) = 0;
 601
 602   virtual bool low_cannot_store_register (int regno) = 0;
 603
 604   /* Hook to fetch a register in some non-standard way.  Used for
 605      example by backends that have read-only registers with hardcoded
 606      values (e.g., IA64's gr0/fr0/fr1).  Returns true if register
 607      REGNO was supplied, false if not, and we should fallback to the
 608      standard ptrace methods.  */
 609   virtual bool low_fetch_register (regcache *regcache, int regno);
 610
 611   /* Return true if breakpoints are supported.  Such targets must
 612      implement the GET_PC and SET_PC methods.  */
 613   virtual bool low_supports_breakpoints ();
 614
 615   virtual CORE_ADDR low_get_pc (regcache *regcache);
 616
 617   virtual void low_set_pc (regcache *regcache, CORE_ADDR newpc);
 618
 619   /* Find the next possible PCs after the current instruction executes.
 620      Targets that override this method should also override
 621      'supports_software_single_step' to return true.  */
 622   virtual std::vector<CORE_ADDR> low_get_next_pcs (regcache *regcache);
 623
 624   /* Return true if there is a breakpoint at PC.  */
 625   virtual bool low_breakpoint_at (CORE_ADDR pc) = 0;
 626
 627   /* Breakpoint and watchpoint related functions.  See target.h for
 628      comments.  */
 629   virtual int low_insert_point (raw_bkpt_type type, CORE_ADDR addr,
 630                                 int size, raw_breakpoint *bp);
 631
 632   virtual int low_remove_point (raw_bkpt_type type, CORE_ADDR addr,
 633                                 int size, raw_breakpoint *bp);
 634
 635   virtual bool low_stopped_by_watchpoint ();
 636
 637   virtual CORE_ADDR low_stopped_data_address ();
 638
 639   /* Hooks to reformat register data for PEEKUSR/POKEUSR (in particular
 640      for registers smaller than an xfer unit).  */
 641   virtual void low_collect_ptrace_register (regcache *regcache, int regno,
 642                                             char *buf);
 643
 644   virtual void low_supply_ptrace_register (regcache *regcache, int regno,
 645                                            const char *buf);
 646
 647   /* Hook to convert from target format to ptrace format and back.
 648      Returns true if any conversion was done; false otherwise.
 649      If DIRECTION is 1, then copy from INF to NATIVE.
 650      If DIRECTION is 0, copy from NATIVE to INF.  */
 651   virtual bool low_siginfo_fixup (siginfo_t *native, gdb_byte *inf,
 652                                   int direction);
 653
 654   /* Hook to call when a new process is created or attached to.
 655      If extra per-process architecture-specific data is needed,
 656      allocate it here.  */
 657   virtual arch_process_info *low_new_process ();
 658
 659   /* Hook to call when a process is being deleted.  If extra per-process
 660      architecture-specific data is needed, delete it here.  */
 661   virtual void low_delete_process (arch_process_info *info);
 662
 663   /* Hook to call when a new thread is detected.
 664      If extra per-thread architecture-specific data is needed,
 665      allocate it here.  */
 666   virtual void low_new_thread (lwp_info *);
 667
 668   /* Hook to call when a thread is being deleted.  If extra per-thread
 669      architecture-specific data is needed, delete it here.  */
 670   virtual void low_delete_thread (arch_lwp_info *);
 671
 672   /* Hook to call, if any, when a new fork is attached.  */
 673   virtual void low_new_fork (process_info *parent, process_info *child);
 674
 675   /* Hook to call prior to resuming a thread.  */
 676   virtual void low_prepare_to_resume (lwp_info *lwp);
 677
 678   /* Fill ADDRP with the thread area address of LWPID.  Returns 0 on
 679      success, -1 on failure.  */
 680   virtual int low_get_thread_area (int lwpid, CORE_ADDR *addrp);
 681
 682   /* Returns true if the low target supports range stepping.  */
 683   virtual bool low_supports_range_stepping ();
 684
 685   /* Return true if the target supports catch syscall.  Such targets
 686      override the low_get_syscall_trapinfo method below.  */
 687   virtual bool low_supports_catch_syscall ();
 688
 689   /* Fill *SYSNO with the syscall nr trapped.  Only to be called when
 690      inferior is stopped due to SYSCALL_SIGTRAP.  */
 691   virtual void low_get_syscall_trapinfo (regcache *regcache, int *sysno);
 692
 693   /* How many bytes the PC should be decremented after a break.  */
 694   virtual int low_decr_pc_after_break ();
 695 };
 696
 697 extern linux_process_target *the_linux_target;
 698
 699 #define get_thread_lwp(thr) ((struct lwp_info *) (thread_target_data (thr)))
 700 #define get_lwp_thread(lwp) ((lwp)->thread)
 701
 702 /* Information about a signal that is to be delivered to a thread.  */
 703
 704 struct pending_signal
 705 {
 706   pending_signal (int signal)
 707     : signal {signal}
 708   {};
 709
 710   int signal;
 711   siginfo_t info;
 712 };
 713
 714 /* This struct is recorded in the target_data field of struct thread_info.
 715
 716    On linux ``all_threads'' is keyed by the LWP ID, which we use as the
 717    GDB protocol representation of the thread ID.  Threads also have
 718    a "process ID" (poorly named) which is (presently) the same as the
 719    LWP ID.
 720
 721    There is also ``all_processes'' is keyed by the "overall process ID",
 722    which GNU/Linux calls tgid, "thread group ID".  */
 723
 724 struct lwp_info
 725 {
 726   lwp_info ()
 727   {
 728     this->waitstatus.kind = TARGET_WAITKIND_IGNORE;
 729   }
 730
 731   /* If this LWP is a fork child that wasn't reported to GDB yet, return
 732      its parent, else nullptr.  */
 733   lwp_info *pending_parent () const
 734   {
 735     if (this->fork_relative == nullptr)
 736       return nullptr;
 737
 738     gdb_assert (this->fork_relative->fork_relative == this);
 739
 740     /* In a fork parent/child relationship, the parent has a status pending and
 741        the child does not, and a thread can only be in one such relationship
 742        at most.  So we can recognize who is the parent based on which one has
 743        a pending status.  */
 744     gdb_assert (!!this->status_pending_p
 745                 != !!this->fork_relative->status_pending_p);
 746
 747     if (!this->fork_relative->status_pending_p)
 748       return nullptr;
 749
 750     const target_waitstatus &ws
 751       = this->fork_relative->waitstatus;
 752     gdb_assert (ws.kind == TARGET_WAITKIND_FORKED
 753                 || ws.kind == TARGET_WAITKIND_VFORKED);
 754
 755     return this->fork_relative;
 756   }
 757
 758   /* Backlink to the parent object.  */
 759   struct thread_info *thread = nullptr;
 760
 761   /* If this flag is set, the next SIGSTOP will be ignored (the
 762      process will be immediately resumed).  This means that either we
 763      sent the SIGSTOP to it ourselves and got some other pending event
 764      (so the SIGSTOP is still pending), or that we stopped the
 765      inferior implicitly via PTRACE_ATTACH and have not waited for it
 766      yet.  */
 767   int stop_expected = 0;
 768
 769   /* When this is true, we shall not try to resume this thread, even
 770      if last_resume_kind isn't resume_stop.  */
 771   int suspended = 0;
 772
 773   /* If this flag is set, the lwp is known to be stopped right now (stop
 774      event already received in a wait()).  */
 775   int stopped = 0;
 776
 777   /* Signal whether we are in a SYSCALL_ENTRY or
 778      in a SYSCALL_RETURN event.
 779      Values:
 780      - TARGET_WAITKIND_SYSCALL_ENTRY
 781      - TARGET_WAITKIND_SYSCALL_RETURN */
 782   enum target_waitkind syscall_state = TARGET_WAITKIND_SYSCALL_ENTRY;
 783
 784   /* When stopped is set, the last wait status recorded for this lwp.  */
 785   int last_status = 0;
 786
 787   /* If WAITSTATUS->KIND != TARGET_WAITKIND_IGNORE, the waitstatus for
 788      this LWP's last event, to pass to GDB without any further
 789      processing.  This is used to store extended ptrace event
 790      information or exit status until it can be reported to GDB.  */
 791   struct target_waitstatus waitstatus;
 792
 793   /* A pointer to the fork child/parent relative.  Valid only while
 794      the parent fork event is not reported to higher layers.  Used to
 795      avoid wildcard vCont actions resuming a fork child before GDB is
 796      notified about the parent's fork event.  */
 797   struct lwp_info *fork_relative = nullptr;
 798
 799   /* When stopped is set, this is where the lwp last stopped, with
 800      decr_pc_after_break already accounted for.  If the LWP is
 801      running, this is the address at which the lwp was resumed.  */
 802   CORE_ADDR stop_pc = 0;
 803
 804   /* If this flag is set, STATUS_PENDING is a waitstatus that has not yet
 805      been reported.  */
 806   int status_pending_p = 0;
 807   int status_pending = 0;
 808
 809   /* The reason the LWP last stopped, if we need to track it
 810      (breakpoint, watchpoint, etc.)  */
 811   enum target_stop_reason stop_reason = TARGET_STOPPED_BY_NO_REASON;
 812
 813   /* On architectures where it is possible to know the data address of
 814      a triggered watchpoint, STOPPED_DATA_ADDRESS is non-zero, and
 815      contains such data address.  Only valid if STOPPED_BY_WATCHPOINT
 816      is true.  */
 817   CORE_ADDR stopped_data_address = 0;
 818
 819   /* If this is non-zero, it is a breakpoint to be reinserted at our next
 820      stop (SIGTRAP stops only).  */
 821   CORE_ADDR bp_reinsert = 0;
 822
 823   /* If this flag is set, the last continue operation at the ptrace
 824      level on this process was a single-step.  */
 825   int stepping = 0;
 826
 827   /* Range to single step within.  This is a copy of the step range
 828      passed along the last resume request.  See 'struct
 829      thread_resume'.  */
 830   CORE_ADDR step_range_start = 0; /* Inclusive */
 831   CORE_ADDR step_range_end = 0; /* Exclusive */
 832
 833   /* If this flag is set, we need to set the event request flags the
 834      next time we see this LWP stop.  */
 835   int must_set_ptrace_flags = 0;
 836
 837   /* A chain of signals that need to be delivered to this process.  */
 838   std::list<pending_signal> pending_signals;
 839
 840   /* A link used when resuming.  It is initialized from the resume request,
 841      and then processed and cleared in linux_resume_one_lwp.  */
 842   struct thread_resume *resume = nullptr;
 843
 844   /* Information bout this lwp's fast tracepoint collection status (is it
 845      currently stopped in the jump pad, and if so, before or at/after the
 846      relocated instruction).  Normally, we won't care about this, but we will
 847      if a signal arrives to this lwp while it is collecting.  */
 848   fast_tpoint_collect_result collecting_fast_tracepoint
 849     = fast_tpoint_collect_result::not_collecting;
 850
 851   /* A chain of signals that need to be reported to GDB.  These were
 852      deferred because the thread was doing a fast tracepoint collect
 853      when they arrived.  */
 854   std::list<pending_signal> pending_signals_to_report;
 855
 856   /* When collecting_fast_tracepoint is first found to be 1, we insert
 857      a exit-jump-pad-quickly breakpoint.  This is it.  */
 858   struct breakpoint *exit_jump_pad_bkpt = nullptr;
 859
 860 #ifdef USE_THREAD_DB
 861   int thread_known = 0;
 862   /* The thread handle, used for e.g. TLS access.  Only valid if
 863      THREAD_KNOWN is set.  */
 864   td_thrhandle_t th {};
 865
 866   /* The pthread_t handle.  */
 867   thread_t thread_handle {};
 868 #endif
 869
 870   /* Arch-specific additions.  */
 871   struct arch_lwp_info *arch_private = nullptr;
 872 };
 873
 874 int linux_pid_exe_is_elf_64_file (int pid, unsigned int *machine);
 875
 876 /* Attach to PTID.  Returns 0 on success, non-zero otherwise (an
 877    errno).  */
 878 int linux_attach_lwp (ptid_t ptid);
 879
 880 struct lwp_info *find_lwp_pid (ptid_t ptid);
 881 /* For linux_stop_lwp see nat/linux-nat.h.  */
 882
 883 #ifdef HAVE_LINUX_REGSETS
 884 void initialize_regsets_info (struct regsets_info *regsets_info);
 885 #endif
 886
 887 void initialize_low_arch (void);
 888
 889 void linux_set_pc_32bit (struct regcache *regcache, CORE_ADDR pc);
 890 CORE_ADDR linux_get_pc_32bit (struct regcache *regcache);
 891
 892 void linux_set_pc_64bit (struct regcache *regcache, CORE_ADDR pc);
 893 CORE_ADDR linux_get_pc_64bit (struct regcache *regcache);
 894
 895 /* From thread-db.c  */
 896 int thread_db_init (void);
 897 void thread_db_detach (struct process_info *);
 898 void thread_db_mourn (struct process_info *);
 899 int thread_db_handle_monitor_command (char *);
 900 int thread_db_get_tls_address (struct thread_info *thread, CORE_ADDR offset,
 901                                CORE_ADDR load_module, CORE_ADDR *address);
 902 int thread_db_look_up_one_symbol (const char *name, CORE_ADDR *addrp);
 903
 904 /* Called from linux-low.c when a clone event is detected.  Upon entry,
 905    both the clone and the parent should be stopped.  This function does
 906    whatever is required have the clone under thread_db's control.  */
 907
 908 void thread_db_notice_clone (struct thread_info *parent_thr, ptid_t child_ptid);
 909
 910 bool thread_db_thread_handle (ptid_t ptid, gdb_byte **handle, int *handle_len);
 911
 912 extern int have_ptrace_getregset;
 913
 914 /* Search for the value with type MATCH in the auxv vector with
 915    entries of length WORDSIZE bytes.  If found, store the value in
 916    *VALP and return 1.  If not found or if there is an error, return
 917    0.  */
 918
 919 int linux_get_auxv (int wordsize, CORE_ADDR match,
 920                     CORE_ADDR *valp);
 921
 922 /* Fetch the AT_HWCAP entry from the auxv vector, where entries are length
 923    WORDSIZE.  If no entry was found, return zero.  */
 924
 925 CORE_ADDR linux_get_hwcap (int wordsize);
 926
 927 /* Fetch the AT_HWCAP2 entry from the auxv vector, where entries are length
 928    WORDSIZE.  If no entry was found, return zero.  */
 929
 930 CORE_ADDR linux_get_hwcap2 (int wordsize);
 931
 932 #endif /* GDBSERVER_LINUX_LOW_H */