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   /* Hook to support target specific qSupported.  */
 135   void (*process_qsupported) (char **, int count);
 136
 137   /* Returns true if the low target supports tracepoints.  */
 138   int (*supports_tracepoints) (void);
 139
 140   /* Fill ADDRP with the thread area address of LWPID.  Returns 0 on
 141      success, -1 on failure.  */
 142   int (*get_thread_area) (int lwpid, CORE_ADDR *addrp);
 143
 144   /* Install a fast tracepoint jump pad.  See target.h for
 145      comments.  */
 146   int (*install_fast_tracepoint_jump_pad) (CORE_ADDR tpoint, CORE_ADDR tpaddr,
 147                                            CORE_ADDR collector,
 148                                            CORE_ADDR lockaddr,
 149                                            ULONGEST orig_size,
 150                                            CORE_ADDR *jump_entry,
 151                                            CORE_ADDR *trampoline,
 152                                            ULONGEST *trampoline_size,
 153                                            unsigned char *jjump_pad_insn,
 154                                            ULONGEST *jjump_pad_insn_size,
 155                                            CORE_ADDR *adjusted_insn_addr,
 156                                            CORE_ADDR *adjusted_insn_addr_end,
 157                                            char *err);
 158
 159   /* Return the bytecode operations vector for the current inferior.
 160      Returns NULL if bytecode compilation is not supported.  */
 161   struct emit_ops *(*emit_ops) (void);
 162
 163   /* Return the minimum length of an instruction that can be safely overwritten
 164      for use as a fast tracepoint.  */
 165   int (*get_min_fast_tracepoint_insn_len) (void);
 166
 167   /* Returns true if the low target supports range stepping.  */
 168   int (*supports_range_stepping) (void);
 169
 170   /* See target.h.  */
 171   int (*supports_hardware_single_step) (void);
 172
 173   /* Fill *SYSNO with the syscall nr trapped.  Only to be called when
 174      inferior is stopped due to SYSCALL_SIGTRAP.  */
 175   void (*get_syscall_trapinfo) (struct regcache *regcache, int *sysno);
 176
 177   /* See target.h.  */
 178   int (*get_ipa_tdesc_idx) (void);
 179 };
 180
 181 extern struct linux_target_ops the_low_target;
 182
 183 /* Target ops definitions for a Linux target.  */
 184
 185 class linux_process_target : public process_stratum_target
 186 {
 187 public:
 188
 189   int create_inferior (const char *program,
 190                        const std::vector<char *> &program_args) override;
 191
 192   void post_create_inferior () override;
 193
 194   int attach (unsigned long pid) override;
 195
 196   int kill (process_info *proc) override;
 197
 198   int detach (process_info *proc) override;
 199
 200   void mourn (process_info *proc) override;
 201
 202   void join (int pid) override;
 203
 204   bool thread_alive (ptid_t pid) override;
 205
 206   void resume (thread_resume *resume_info, size_t n) override;
 207
 208   ptid_t wait (ptid_t ptid, target_waitstatus *status,
 209                int options) override;
 210
 211   void fetch_registers (regcache *regcache, int regno) override;
 212
 213   void store_registers (regcache *regcache, int regno) override;
 214
 215   int prepare_to_access_memory () override;
 216
 217   void done_accessing_memory () override;
 218
 219   int read_memory (CORE_ADDR memaddr, unsigned char *myaddr,
 220                    int len) override;
 221
 222   int write_memory (CORE_ADDR memaddr, const unsigned char *myaddr,
 223                     int len) override;
 224
 225   void look_up_symbols () override;
 226
 227   void request_interrupt () override;
 228
 229   bool supports_read_auxv () override;
 230
 231   int read_auxv (CORE_ADDR offset, unsigned char *myaddr,
 232                  unsigned int len) override;
 233
 234   int insert_point (enum raw_bkpt_type type, CORE_ADDR addr,
 235                     int size, raw_breakpoint *bp) override;
 236
 237   int remove_point (enum raw_bkpt_type type, CORE_ADDR addr,
 238                     int size, raw_breakpoint *bp) override;
 239
 240   bool stopped_by_sw_breakpoint () override;
 241
 242   bool supports_stopped_by_sw_breakpoint () override;
 243
 244   bool stopped_by_hw_breakpoint () override;
 245
 246   bool supports_stopped_by_hw_breakpoint () override;
 247
 248   bool supports_hardware_single_step () override;
 249
 250   bool stopped_by_watchpoint () override;
 251
 252   CORE_ADDR stopped_data_address () override;
 253
 254   bool supports_read_offsets () override;
 255
 256   int read_offsets (CORE_ADDR *text, CORE_ADDR *data) override;
 257
 258   bool supports_get_tls_address () override;
 259
 260   int get_tls_address (thread_info *thread, CORE_ADDR offset,
 261                        CORE_ADDR load_module, CORE_ADDR *address) override;
 262
 263   bool supports_qxfer_osdata () override;
 264
 265   int qxfer_osdata (const char *annex, unsigned char *readbuf,
 266                     unsigned const char *writebuf,
 267                     CORE_ADDR offset, int len) override;
 268
 269   bool supports_qxfer_siginfo () override;
 270
 271   int qxfer_siginfo (const char *annex, unsigned char *readbuf,
 272                      unsigned const char *writebuf,
 273                      CORE_ADDR offset, int len) override;
 274
 275   bool supports_non_stop () override;
 276
 277   bool async (bool enable) override;
 278
 279   int start_non_stop (bool enable) override;
 280
 281   bool supports_multi_process () override;
 282
 283   bool supports_fork_events () override;
 284
 285   bool supports_vfork_events () override;
 286
 287   bool supports_exec_events () override;
 288
 289   void handle_new_gdb_connection () override;
 290
 291   int handle_monitor_command (char *mon) override;
 292
 293   int core_of_thread (ptid_t ptid) override;
 294
 295 #if defined PT_GETDSBT || defined PTRACE_GETFDPIC
 296   bool supports_read_loadmap () override;
 297
 298   int read_loadmap (const char *annex, CORE_ADDR offset,
 299                     unsigned char *myaddr, unsigned int len) override;
 300 #endif
 301
 302   void process_qsupported (char **features, int count) override;
 303
 304   bool supports_tracepoints () override;
 305
 306   CORE_ADDR read_pc (regcache *regcache) override;
 307
 308   void write_pc (regcache *regcache, CORE_ADDR pc) override;
 309
 310   bool supports_thread_stopped () override;
 311
 312   bool thread_stopped (thread_info *thread) override;
 313
 314   void pause_all (bool freeze) override;
 315
 316   void unpause_all (bool unfreeze) override;
 317
 318   void stabilize_threads () override;
 319
 320   bool supports_fast_tracepoints () override;
 321
 322   int install_fast_tracepoint_jump_pad (CORE_ADDR tpoint,
 323                                         CORE_ADDR tpaddr,
 324                                         CORE_ADDR collector,
 325                                         CORE_ADDR lockaddr,
 326                                         ULONGEST orig_size,
 327                                         CORE_ADDR *jump_entry,
 328                                         CORE_ADDR *trampoline,
 329                                         ULONGEST *trampoline_size,
 330                                         unsigned char *jjump_pad_insn,
 331                                         ULONGEST *jjump_pad_insn_size,
 332                                         CORE_ADDR *adjusted_insn_addr,
 333                                         CORE_ADDR *adjusted_insn_addr_end,
 334                                         char *err) override;
 335
 336   int get_min_fast_tracepoint_insn_len () override;
 337
 338   struct emit_ops *emit_ops () override;
 339
 340   bool supports_disable_randomization () override;
 341
 342   bool supports_qxfer_libraries_svr4 () override;
 343
 344   int qxfer_libraries_svr4 (const char *annex,
 345                             unsigned char *readbuf,
 346                             unsigned const char *writebuf,
 347                             CORE_ADDR offset, int len) override;
 348
 349   bool supports_agent () override;
 350
 351 #ifdef HAVE_LINUX_BTRACE
 352   btrace_target_info *enable_btrace (ptid_t ptid,
 353                                      const btrace_config *conf) override;
 354
 355   int disable_btrace (btrace_target_info *tinfo) override;
 356
 357   int read_btrace (btrace_target_info *tinfo, buffer *buf,
 358                    enum btrace_read_type type) override;
 359
 360   int read_btrace_conf (const btrace_target_info *tinfo,
 361                         buffer *buf) override;
 362 #endif
 363
 364   bool supports_range_stepping () override;
 365
 366   bool supports_pid_to_exec_file () override;
 367
 368   char *pid_to_exec_file (int pid) override;
 369
 370   bool supports_multifs () override;
 371
 372   int multifs_open (int pid, const char *filename, int flags,
 373                     mode_t mode) override;
 374
 375   int multifs_unlink (int pid, const char *filename) override;
 376
 377   ssize_t multifs_readlink (int pid, const char *filename, char *buf,
 378                             size_t bufsiz) override;
 379
 380   const char *thread_name (ptid_t thread) override;
 381
 382 #if USE_THREAD_DB
 383   bool thread_handle (ptid_t ptid, gdb_byte **handle,
 384                       int *handle_len) override;
 385 #endif
 386
 387   bool supports_catch_syscall () override;
 388
 389   int get_ipa_tdesc_idx () override;
 390
 391   /* Return the information to access registers.  This has public
 392      visibility because proc-service uses it.  */
 393   virtual const regs_info *get_regs_info () = 0;
 394
 395 private:
 396
 397   /* Handle a GNU/Linux extended wait response.  If we see a clone,
 398      fork, or vfork event, we need to add the new LWP to our list
 399      (and return 0 so as not to report the trap to higher layers).
 400      If we see an exec event, we will modify ORIG_EVENT_LWP to point
 401      to a new LWP representing the new program.  */
 402   int handle_extended_wait (lwp_info **orig_event_lwp, int wstat);
 403
 404   /* Do low-level handling of the event, and check if we should go on
 405      and pass it to caller code.  Return the affected lwp if we are, or
 406      NULL otherwise.  */
 407   lwp_info *filter_event (int lwpid, int wstat);
 408
 409   /* Wait for an event from child(ren) WAIT_PTID, and return any that
 410      match FILTER_PTID (leaving others pending).  The 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_filtered (ptid_t wait_ptid, ptid_t filter_ptid,
 418                                int *wstatp, int options);
 419
 420   /* Wait for an event from child(ren) PTID.  PTIDs can be:
 421      minus_one_ptid, to specify any child; a pid PTID, specifying all
 422      lwps of a thread group; or a PTID representing a single lwp.  Store
 423      the stop status through the status pointer WSTAT.  OPTIONS is
 424      passed to the waitpid call.  Return 0 if no event was found and
 425      OPTIONS contains WNOHANG.  Return -1 if no unwaited-for children
 426      was found.  Return the PID of the stopped child otherwise.  */
 427   int wait_for_event (ptid_t ptid, int *wstatp, int options);
 428
 429   /* Wait for all children to stop for the SIGSTOPs we just queued.  */
 430   void wait_for_sigstop ();
 431
 432   /* Wait for process, returns status.  */
 433   ptid_t wait_1 (ptid_t ptid, target_waitstatus *ourstatus,
 434                  int target_options);
 435
 436   /* Stop all lwps that aren't stopped yet, except EXCEPT, if not NULL.
 437      If SUSPEND, then also increase the suspend count of every LWP,
 438      except EXCEPT.  */
 439   void stop_all_lwps (int suspend, lwp_info *except);
 440
 441   /* Stopped LWPs that the client wanted to be running, that don't have
 442      pending statuses, are set to run again, except for EXCEPT, if not
 443      NULL.  This undoes a stop_all_lwps call.  */
 444   void unstop_all_lwps (int unsuspend, lwp_info *except);
 445
 446   /* Start a step-over operation on LWP.  When LWP stopped at a
 447      breakpoint, to make progress, we need to remove the breakpoint out
 448      of the way.  If we let other threads run while we do that, they may
 449      pass by the breakpoint location and miss hitting it.  To avoid
 450      that, a step-over momentarily stops all threads while LWP is
 451      single-stepped by either hardware or software while the breakpoint
 452      is temporarily uninserted from the inferior.  When the single-step
 453      finishes, we reinsert the breakpoint, and let all threads that are
 454      supposed to be running, run again.  */
 455   void start_step_over (lwp_info *lwp);
 456
 457   /* If there's a step over in progress, wait until all threads stop
 458      (that is, until the stepping thread finishes its step), and
 459      unsuspend all lwps.  The stepping thread ends with its status
 460      pending, which is processed later when we get back to processing
 461      events.  */
 462   void complete_ongoing_step_over ();
 463
 464   /* When we finish a step-over, set threads running again.  If there's
 465      another thread that may need a step-over, now's the time to start
 466      it.  Eventually, we'll move all threads past their breakpoints.  */
 467   void proceed_all_lwps ();
 468
 469   /* The reason we resume in the caller, is because we want to be able
 470      to pass lwp->status_pending as WSTAT, and we need to clear
 471      status_pending_p before resuming, otherwise, resume_one_lwp
 472      refuses to resume.  */
 473   bool maybe_move_out_of_jump_pad (lwp_info *lwp, int *wstat);
 474
 475   /* Move THREAD out of the jump pad.  */
 476   void move_out_of_jump_pad (thread_info *thread);
 477
 478   /* Call low_arch_setup on THREAD.  */
 479   void arch_setup_thread (thread_info *thread);
 480
 481 #ifdef HAVE_LINUX_USRREGS
 482   /* Fetch one register.  */
 483   void fetch_register (const usrregs_info *usrregs, regcache *regcache,
 484                        int regno);
 485
 486   /* Store one register.  */
 487   void store_register (const usrregs_info *usrregs, regcache *regcache,
 488                        int regno);
 489 #endif
 490
 491   /* Fetch all registers, or just one, from the child process.
 492      If REGNO is -1, do this for all registers, skipping any that are
 493      assumed to have been retrieved by regsets_fetch_inferior_registers,
 494      unless ALL is non-zero.
 495      Otherwise, REGNO specifies which register (so we can save time).  */
 496   void usr_fetch_inferior_registers (const regs_info *regs_info,
 497                                      regcache *regcache, int regno, int all);
 498
 499   /* Store our register values back into the inferior.
 500      If REGNO is -1, do this for all registers, skipping any that are
 501      assumed to have been saved by regsets_store_inferior_registers,
 502      unless ALL is non-zero.
 503      Otherwise, REGNO specifies which register (so we can save time).  */
 504   void usr_store_inferior_registers (const regs_info *regs_info,
 505                                      regcache *regcache, int regno, int all);
 506
 507   /* Return the PC as read from the regcache of LWP, without any
 508      adjustment.  */
 509   CORE_ADDR get_pc (lwp_info *lwp);
 510
 511   /* Called when the LWP stopped for a signal/trap.  If it stopped for a
 512      trap check what caused it (breakpoint, watchpoint, trace, etc.),
 513      and save the result in the LWP's stop_reason field.  If it stopped
 514      for a breakpoint, decrement the PC if necessary on the lwp's
 515      architecture.  Returns true if we now have the LWP's stop PC.  */
 516   bool save_stop_reason (lwp_info *lwp);
 517
 518   /* Resume execution of LWP.  If STEP is nonzero, single-step it.  If
 519      SIGNAL is nonzero, give it that signal.  */
 520   void resume_one_lwp_throw (lwp_info *lwp, int step, int signal,
 521                              siginfo_t *info);
 522
 523   /* Like resume_one_lwp_throw, but no error is thrown if the LWP
 524      disappears while we try to resume it.  */
 525   void resume_one_lwp (lwp_info *lwp, int step, int signal, siginfo_t *info);
 526
 527   /* This function is called once per thread.  We check the thread's
 528      last resume request, which will tell us whether to resume, step, or
 529      leave the thread stopped.  Any signal the client requested to be
 530      delivered has already been enqueued at this point.
 531
 532      If any thread that GDB wants running is stopped at an internal
 533      breakpoint that needs stepping over, we start a step-over operation
 534      on that particular thread, and leave all others stopped.  */
 535   void proceed_one_lwp (thread_info *thread, lwp_info *except);
 536
 537   /* This function is called once per thread.  We check the thread's
 538      resume request, which will tell us whether to resume, step, or
 539      leave the thread stopped; and what signal, if any, it should be
 540      sent.
 541
 542      For threads which we aren't explicitly told otherwise, we preserve
 543      the stepping flag; this is used for stepping over gdbserver-placed
 544      breakpoints.
 545
 546      If pending_flags was set in any thread, we queue any needed
 547      signals, since we won't actually resume.  We already have a pending
 548      event to report, so we don't need to preserve any step requests;
 549      they should be re-issued if necessary.  */
 550   void resume_one_thread (thread_info *thread, bool leave_all_stopped);
 551
 552   /* Return true if this lwp has an interesting status pending.  */
 553   bool status_pending_p_callback (thread_info *thread, ptid_t ptid);
 554
 555   /* Resume LWPs that are currently stopped without any pending status
 556      to report, but are resumed from the core's perspective.  */
 557   void resume_stopped_resumed_lwps (thread_info *thread);
 558
 559   /* Unsuspend THREAD, except EXCEPT, and proceed.  */
 560   void unsuspend_and_proceed_one_lwp (thread_info *thread, lwp_info *except);
 561
 562   /* Return true if this lwp still has an interesting status pending.
 563      If not (e.g., it had stopped for a breakpoint that is gone), return
 564      false.  */
 565   bool thread_still_has_status_pending (thread_info *thread);
 566
 567   /* Return true if this lwp is to-be-resumed and has an interesting
 568      status pending.  */
 569   bool resume_status_pending (thread_info *thread);
 570
 571   /* Return true if this lwp that GDB wants running is stopped at an
 572      internal breakpoint that we need to step over.  It assumes that
 573      any required STOP_PC adjustment has already been propagated to
 574      the inferior's regcache.  */
 575   bool thread_needs_step_over (thread_info *thread);
 576
 577   /* Single step via hardware or software single step.
 578      Return 1 if hardware single stepping, 0 if software single stepping
 579      or can't single step.  */
 580   int single_step (lwp_info* lwp);
 581
 582   /* Install breakpoints for software single stepping.  */
 583   void install_software_single_step_breakpoints (lwp_info *lwp);
 584
 585   /* Fetch the possibly triggered data watchpoint info and store it in
 586      CHILD.
 587
 588      On some archs, like x86, that use debug registers to set
 589      watchpoints, it's possible that the way to know which watched
 590      address trapped, is to check the register that is used to select
 591      which address to watch.  Problem is, between setting the watchpoint
 592      and reading back which data address trapped, the user may change
 593      the set of watchpoints, and, as a consequence, GDB changes the
 594      debug registers in the inferior.  To avoid reading back a stale
 595      stopped-data-address when that happens, we cache in LP the fact
 596      that a watchpoint trapped, and the corresponding data address, as
 597      soon as we see CHILD stop with a SIGTRAP.  If GDB changes the debug
 598      registers meanwhile, we have the cached data we can rely on.  */
 599   bool check_stopped_by_watchpoint (lwp_info *child);
 600
 601   /* Convert a native/host siginfo object, into/from the siginfo in the
 602      layout of the inferiors' architecture.  */
 603   void siginfo_fixup (siginfo_t *siginfo, gdb_byte *inf_siginfo,
 604                       int direction);
 605
 606   /* Add a process to the common process list, and set its private
 607      data.  */
 608   process_info *add_linux_process (int pid, int attached);
 609
 610   /* Add a new thread.  */
 611   lwp_info *add_lwp (ptid_t ptid);
 612
 613   /* Delete a thread.  */
 614   void delete_lwp (lwp_info *lwp);
 615
 616 public: /* Make this public because it's used from outside.  */
 617   /* Attach to an inferior process.  Returns 0 on success, ERRNO on
 618      error.  */
 619   int attach_lwp (ptid_t ptid);
 620
 621 private: /* Back to private.  */
 622   /* Detach from LWP.  */
 623   void detach_one_lwp (lwp_info *lwp);
 624
 625   /* Detect zombie thread group leaders, and "exit" them.  We can't
 626      reap their exits until all other threads in the group have
 627      exited.  */
 628   void check_zombie_leaders ();
 629
 630   /* Convenience function that is called when the kernel reports an exit
 631      event.  This decides whether to report the event to GDB as a
 632      process exit event, a thread exit event, or to suppress the
 633      event.  */
 634   ptid_t filter_exit_event (lwp_info *event_child,
 635                             target_waitstatus *ourstatus);
 636
 637 protected:
 638   /* The architecture-specific "low" methods are listed below.  */
 639
 640   /* Architecture-specific setup for the current thread.  */
 641   virtual void low_arch_setup () = 0;
 642
 643   /* Return false if we can fetch/store the register, true if we cannot
 644      fetch/store the register.  */
 645   virtual bool low_cannot_fetch_register (int regno) = 0;
 646
 647   virtual bool low_cannot_store_register (int regno) = 0;
 648
 649   /* Hook to fetch a register in some non-standard way.  Used for
 650      example by backends that have read-only registers with hardcoded
 651      values (e.g., IA64's gr0/fr0/fr1).  Returns true if register
 652      REGNO was supplied, false if not, and we should fallback to the
 653      standard ptrace methods.  */
 654   virtual bool low_fetch_register (regcache *regcache, int regno);
 655
 656   /* Return true if breakpoints are supported.  Such targets must
 657      implement the GET_PC and SET_PC methods.  */
 658   virtual bool low_supports_breakpoints ();
 659
 660   virtual CORE_ADDR low_get_pc (regcache *regcache);
 661
 662   virtual void low_set_pc (regcache *regcache, CORE_ADDR newpc);
 663
 664   /* Find the next possible PCs after the current instruction executes.
 665      Targets that override this method should also override
 666      'supports_software_single_step' to return true.  */
 667   virtual std::vector<CORE_ADDR> low_get_next_pcs (regcache *regcache);
 668
 669   /* Return true if there is a breakpoint at PC.  */
 670   virtual bool low_breakpoint_at (CORE_ADDR pc) = 0;
 671
 672   /* Breakpoint and watchpoint related functions.  See target.h for
 673      comments.  */
 674   virtual int low_insert_point (raw_bkpt_type type, CORE_ADDR addr,
 675                                 int size, raw_breakpoint *bp);
 676
 677   virtual int low_remove_point (raw_bkpt_type type, CORE_ADDR addr,
 678                                 int size, raw_breakpoint *bp);
 679
 680   virtual bool low_stopped_by_watchpoint ();
 681
 682   virtual CORE_ADDR low_stopped_data_address ();
 683
 684   /* Hooks to reformat register data for PEEKUSR/POKEUSR (in particular
 685      for registers smaller than an xfer unit).  */
 686   virtual void low_collect_ptrace_register (regcache *regcache, int regno,
 687                                             char *buf);
 688
 689   virtual void low_supply_ptrace_register (regcache *regcache, int regno,
 690                                            const char *buf);
 691
 692   /* Hook to convert from target format to ptrace format and back.
 693      Returns true if any conversion was done; false otherwise.
 694      If DIRECTION is 1, then copy from INF to NATIVE.
 695      If DIRECTION is 0, copy from NATIVE to INF.  */
 696   virtual bool low_siginfo_fixup (siginfo_t *native, gdb_byte *inf,
 697                                   int direction);
 698
 699   /* Hook to call when a new process is created or attached to.
 700      If extra per-process architecture-specific data is needed,
 701      allocate it here.  */
 702   virtual arch_process_info *low_new_process ();
 703
 704   /* Hook to call when a process is being deleted.  If extra per-process
 705      architecture-specific data is needed, delete it here.  */
 706   virtual void low_delete_process (arch_process_info *info);
 707
 708   /* Hook to call when a new thread is detected.
 709      If extra per-thread architecture-specific data is needed,
 710      allocate it here.  */
 711   virtual void low_new_thread (lwp_info *);
 712
 713   /* Hook to call when a thread is being deleted.  If extra per-thread
 714      architecture-specific data is needed, delete it here.  */
 715   virtual void low_delete_thread (arch_lwp_info *);
 716
 717   /* Hook to call, if any, when a new fork is attached.  */
 718   virtual void low_new_fork (process_info *parent, process_info *child);
 719
 720   /* Hook to call prior to resuming a thread.  */
 721   virtual void low_prepare_to_resume (lwp_info *lwp);
 722
 723   /* How many bytes the PC should be decremented after a break.  */
 724   virtual int low_decr_pc_after_break ();
 725 };
 726
 727 extern linux_process_target *the_linux_target;
 728
 729 #define get_thread_lwp(thr) ((struct lwp_info *) (thread_target_data (thr)))
 730 #define get_lwp_thread(lwp) ((lwp)->thread)
 731
 732 /* This struct is recorded in the target_data field of struct thread_info.
 733
 734    On linux ``all_threads'' is keyed by the LWP ID, which we use as the
 735    GDB protocol representation of the thread ID.  Threads also have
 736    a "process ID" (poorly named) which is (presently) the same as the
 737    LWP ID.
 738
 739    There is also ``all_processes'' is keyed by the "overall process ID",
 740    which GNU/Linux calls tgid, "thread group ID".  */
 741
 742 struct lwp_info
 743 {
 744   /* Backlink to the parent object.  */
 745   struct thread_info *thread;
 746
 747   /* If this flag is set, the next SIGSTOP will be ignored (the
 748      process will be immediately resumed).  This means that either we
 749      sent the SIGSTOP to it ourselves and got some other pending event
 750      (so the SIGSTOP is still pending), or that we stopped the
 751      inferior implicitly via PTRACE_ATTACH and have not waited for it
 752      yet.  */
 753   int stop_expected;
 754
 755   /* When this is true, we shall not try to resume this thread, even
 756      if last_resume_kind isn't resume_stop.  */
 757   int suspended;
 758
 759   /* If this flag is set, the lwp is known to be stopped right now (stop
 760      event already received in a wait()).  */
 761   int stopped;
 762
 763   /* Signal whether we are in a SYSCALL_ENTRY or
 764      in a SYSCALL_RETURN event.
 765      Values:
 766      - TARGET_WAITKIND_SYSCALL_ENTRY
 767      - TARGET_WAITKIND_SYSCALL_RETURN */
 768   enum target_waitkind syscall_state;
 769
 770   /* When stopped is set, the last wait status recorded for this lwp.  */
 771   int last_status;
 772
 773   /* If WAITSTATUS->KIND != TARGET_WAITKIND_IGNORE, the waitstatus for
 774      this LWP's last event, to pass to GDB without any further
 775      processing.  This is used to store extended ptrace event
 776      information or exit status until it can be reported to GDB.  */
 777   struct target_waitstatus waitstatus;
 778
 779   /* A pointer to the fork child/parent relative.  Valid only while
 780      the parent fork event is not reported to higher layers.  Used to
 781      avoid wildcard vCont actions resuming a fork child before GDB is
 782      notified about the parent's fork event.  */
 783   struct lwp_info *fork_relative;
 784
 785   /* When stopped is set, this is where the lwp last stopped, with
 786      decr_pc_after_break already accounted for.  If the LWP is
 787      running, this is the address at which the lwp was resumed.  */
 788   CORE_ADDR stop_pc;
 789
 790   /* If this flag is set, STATUS_PENDING is a waitstatus that has not yet
 791      been reported.  */
 792   int status_pending_p;
 793   int status_pending;
 794
 795   /* The reason the LWP last stopped, if we need to track it
 796      (breakpoint, watchpoint, etc.)  */
 797   enum target_stop_reason stop_reason;
 798
 799   /* On architectures where it is possible to know the data address of
 800      a triggered watchpoint, STOPPED_DATA_ADDRESS is non-zero, and
 801      contains such data address.  Only valid if STOPPED_BY_WATCHPOINT
 802      is true.  */
 803   CORE_ADDR stopped_data_address;
 804
 805   /* If this is non-zero, it is a breakpoint to be reinserted at our next
 806      stop (SIGTRAP stops only).  */
 807   CORE_ADDR bp_reinsert;
 808
 809   /* If this flag is set, the last continue operation at the ptrace
 810      level on this process was a single-step.  */
 811   int stepping;
 812
 813   /* Range to single step within.  This is a copy of the step range
 814      passed along the last resume request.  See 'struct
 815      thread_resume'.  */
 816   CORE_ADDR step_range_start;   /* Inclusive */
 817   CORE_ADDR step_range_end;     /* Exclusive */
 818
 819   /* If this flag is set, we need to set the event request flags the
 820      next time we see this LWP stop.  */
 821   int must_set_ptrace_flags;
 822
 823   /* If this is non-zero, it points to a chain of signals which need to
 824      be delivered to this process.  */
 825   struct pending_signals *pending_signals;
 826
 827   /* A link used when resuming.  It is initialized from the resume request,
 828      and then processed and cleared in linux_resume_one_lwp.  */
 829   struct thread_resume *resume;
 830
 831   /* Information bout this lwp's fast tracepoint collection status (is it
 832      currently stopped in the jump pad, and if so, before or at/after the
 833      relocated instruction).  Normally, we won't care about this, but we will
 834      if a signal arrives to this lwp while it is collecting.  */
 835   fast_tpoint_collect_result collecting_fast_tracepoint;
 836
 837   /* If this is non-zero, it points to a chain of signals which need
 838      to be reported to GDB.  These were deferred because the thread
 839      was doing a fast tracepoint collect when they arrived.  */
 840   struct pending_signals *pending_signals_to_report;
 841
 842   /* When collecting_fast_tracepoint is first found to be 1, we insert
 843      a exit-jump-pad-quickly breakpoint.  This is it.  */
 844   struct breakpoint *exit_jump_pad_bkpt;
 845
 846 #ifdef USE_THREAD_DB
 847   int thread_known;
 848   /* The thread handle, used for e.g. TLS access.  Only valid if
 849      THREAD_KNOWN is set.  */
 850   td_thrhandle_t th;
 851
 852   /* The pthread_t handle.  */
 853   thread_t thread_handle;
 854 #endif
 855
 856   /* Arch-specific additions.  */
 857   struct arch_lwp_info *arch_private;
 858 };
 859
 860 int linux_pid_exe_is_elf_64_file (int pid, unsigned int *machine);
 861
 862 /* Attach to PTID.  Returns 0 on success, non-zero otherwise (an
 863    errno).  */
 864 int linux_attach_lwp (ptid_t ptid);
 865
 866 struct lwp_info *find_lwp_pid (ptid_t ptid);
 867 /* For linux_stop_lwp see nat/linux-nat.h.  */
 868
 869 #ifdef HAVE_LINUX_REGSETS
 870 void initialize_regsets_info (struct regsets_info *regsets_info);
 871 #endif
 872
 873 void initialize_low_arch (void);
 874
 875 void linux_set_pc_32bit (struct regcache *regcache, CORE_ADDR pc);
 876 CORE_ADDR linux_get_pc_32bit (struct regcache *regcache);
 877
 878 void linux_set_pc_64bit (struct regcache *regcache, CORE_ADDR pc);
 879 CORE_ADDR linux_get_pc_64bit (struct regcache *regcache);
 880
 881 /* From thread-db.c  */
 882 int thread_db_init (void);
 883 void thread_db_detach (struct process_info *);
 884 void thread_db_mourn (struct process_info *);
 885 int thread_db_handle_monitor_command (char *);
 886 int thread_db_get_tls_address (struct thread_info *thread, CORE_ADDR offset,
 887                                CORE_ADDR load_module, CORE_ADDR *address);
 888 int thread_db_look_up_one_symbol (const char *name, CORE_ADDR *addrp);
 889
 890 /* Called from linux-low.c when a clone event is detected.  Upon entry,
 891    both the clone and the parent should be stopped.  This function does
 892    whatever is required have the clone under thread_db's control.  */
 893
 894 void thread_db_notice_clone (struct thread_info *parent_thr, ptid_t child_ptid);
 895
 896 bool thread_db_thread_handle (ptid_t ptid, gdb_byte **handle, int *handle_len);
 897
 898 extern int have_ptrace_getregset;
 899
 900 /* Search for the value with type MATCH in the auxv vector with
 901    entries of length WORDSIZE bytes.  If found, store the value in
 902    *VALP and return 1.  If not found or if there is an error, return
 903    0.  */
 904
 905 int linux_get_auxv (int wordsize, CORE_ADDR match,
 906                     CORE_ADDR *valp);
 907
 908 /* Fetch the AT_HWCAP entry from the auxv vector, where entries are length
 909    WORDSIZE.  If no entry was found, return zero.  */
 910
 911 CORE_ADDR linux_get_hwcap (int wordsize);
 912
 913 /* Fetch the AT_HWCAP2 entry from the auxv vector, where entries are length
 914    WORDSIZE.  If no entry was found, return zero.  */
 915
 916 CORE_ADDR linux_get_hwcap2 (int wordsize);
 917
 918 #endif /* GDBSERVER_LINUX_LOW_H */