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