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   /* Architecture-specific setup.  */
 135   void (*arch_setup) (void);
 136
 137   const struct regs_info *(*regs_info) (void);
 138   int (*cannot_fetch_register) (int);
 139
 140   /* Returns 0 if we can store the register, 1 if we can not
 141      store the register, and 2 if failure to store the register
 142      is acceptable.  */
 143   int (*cannot_store_register) (int);
 144
 145   /* Hook to fetch a register in some non-standard way.  Used for
 146      example by backends that have read-only registers with hardcoded
 147      values (e.g., IA64's gr0/fr0/fr1).  Returns true if register
 148      REGNO was supplied, false if not, and we should fallback to the
 149      standard ptrace methods.  */
 150   int (*fetch_register) (struct regcache *regcache, int regno);
 151
 152   CORE_ADDR (*get_pc) (struct regcache *regcache);
 153   void (*set_pc) (struct regcache *regcache, CORE_ADDR newpc);
 154
 155   /* See target.h for details.  */
 156   int (*breakpoint_kind_from_pc) (CORE_ADDR *pcptr);
 157
 158   /* See target.h for details.  */
 159   const gdb_byte *(*sw_breakpoint_from_kind) (int kind, int *size);
 160
 161   /* Find the next possible PCs after the current instruction executes.  */
 162   std::vector<CORE_ADDR> (*get_next_pcs) (struct regcache *regcache);
 163
 164   int decr_pc_after_break;
 165   int (*breakpoint_at) (CORE_ADDR pc);
 166
 167   /* Breakpoint and watchpoint related functions.  See target.h for
 168      comments.  */
 169   int (*supports_z_point_type) (char z_type);
 170   int (*insert_point) (enum raw_bkpt_type type, CORE_ADDR addr,
 171                        int size, struct raw_breakpoint *bp);
 172   int (*remove_point) (enum raw_bkpt_type type, CORE_ADDR addr,
 173                        int size, struct raw_breakpoint *bp);
 174
 175   int (*stopped_by_watchpoint) (void);
 176   CORE_ADDR (*stopped_data_address) (void);
 177
 178   /* Hooks to reformat register data for PEEKUSR/POKEUSR (in particular
 179      for registers smaller than an xfer unit).  */
 180   void (*collect_ptrace_register) (struct regcache *regcache,
 181                                    int regno, char *buf);
 182   void (*supply_ptrace_register) (struct regcache *regcache,
 183                                   int regno, const char *buf);
 184
 185   /* Hook to convert from target format to ptrace format and back.
 186      Returns true if any conversion was done; false otherwise.
 187      If DIRECTION is 1, then copy from INF to NATIVE.
 188      If DIRECTION is 0, copy from NATIVE to INF.  */
 189   int (*siginfo_fixup) (siginfo_t *native, gdb_byte *inf, int direction);
 190
 191   /* Hook to call when a new process is created or attached to.
 192      If extra per-process architecture-specific data is needed,
 193      allocate it here.  */
 194   struct arch_process_info * (*new_process) (void);
 195
 196   /* Hook to call when a process is being deleted.  If extra per-process
 197      architecture-specific data is needed, delete it here.  */
 198   void (*delete_process) (struct arch_process_info *info);
 199
 200   /* Hook to call when a new thread is detected.
 201      If extra per-thread architecture-specific data is needed,
 202      allocate it here.  */
 203   void (*new_thread) (struct lwp_info *);
 204
 205   /* Hook to call when a thread is being deleted.  If extra per-thread
 206      architecture-specific data is needed, delete it here.  */
 207   void (*delete_thread) (struct arch_lwp_info *);
 208
 209   /* Hook to call, if any, when a new fork is attached.  */
 210   void (*new_fork) (struct process_info *parent, struct process_info *child);
 211
 212   /* Hook to call prior to resuming a thread.  */
 213   void (*prepare_to_resume) (struct lwp_info *);
 214
 215   /* Hook to support target specific qSupported.  */
 216   void (*process_qsupported) (char **, int count);
 217
 218   /* Returns true if the low target supports tracepoints.  */
 219   int (*supports_tracepoints) (void);
 220
 221   /* Fill ADDRP with the thread area address of LWPID.  Returns 0 on
 222      success, -1 on failure.  */
 223   int (*get_thread_area) (int lwpid, CORE_ADDR *addrp);
 224
 225   /* Install a fast tracepoint jump pad.  See target.h for
 226      comments.  */
 227   int (*install_fast_tracepoint_jump_pad) (CORE_ADDR tpoint, CORE_ADDR tpaddr,
 228                                            CORE_ADDR collector,
 229                                            CORE_ADDR lockaddr,
 230                                            ULONGEST orig_size,
 231                                            CORE_ADDR *jump_entry,
 232                                            CORE_ADDR *trampoline,
 233                                            ULONGEST *trampoline_size,
 234                                            unsigned char *jjump_pad_insn,
 235                                            ULONGEST *jjump_pad_insn_size,
 236                                            CORE_ADDR *adjusted_insn_addr,
 237                                            CORE_ADDR *adjusted_insn_addr_end,
 238                                            char *err);
 239
 240   /* Return the bytecode operations vector for the current inferior.
 241      Returns NULL if bytecode compilation is not supported.  */
 242   struct emit_ops *(*emit_ops) (void);
 243
 244   /* Return the minimum length of an instruction that can be safely overwritten
 245      for use as a fast tracepoint.  */
 246   int (*get_min_fast_tracepoint_insn_len) (void);
 247
 248   /* Returns true if the low target supports range stepping.  */
 249   int (*supports_range_stepping) (void);
 250
 251   /* See target.h.  */
 252   int (*breakpoint_kind_from_current_state) (CORE_ADDR *pcptr);
 253
 254   /* See target.h.  */
 255   int (*supports_hardware_single_step) (void);
 256
 257   /* Fill *SYSNO with the syscall nr trapped.  Only to be called when
 258      inferior is stopped due to SYSCALL_SIGTRAP.  */
 259   void (*get_syscall_trapinfo) (struct regcache *regcache, int *sysno);
 260
 261   /* See target.h.  */
 262   int (*get_ipa_tdesc_idx) (void);
 263 };
 264
 265 extern struct linux_target_ops the_low_target;
 266
 267 /* Target ops definitions for a Linux target.  */
 268
 269 class linux_process_target : public process_target
 270 {
 271 public:
 272
 273   int create_inferior (const char *program,
 274                        const std::vector<char *> &program_args) override;
 275
 276   void post_create_inferior () override;
 277
 278   int attach (unsigned long pid) override;
 279
 280   int kill (process_info *proc) override;
 281
 282   int detach (process_info *proc) override;
 283
 284   void mourn (process_info *proc) override;
 285
 286   void join (int pid) override;
 287
 288   bool thread_alive (ptid_t pid) override;
 289
 290   void resume (thread_resume *resume_info, size_t n) override;
 291
 292   ptid_t wait (ptid_t ptid, target_waitstatus *status,
 293                int options) override;
 294
 295   void fetch_registers (regcache *regcache, int regno) override;
 296
 297   void store_registers (regcache *regcache, int regno) override;
 298
 299   int prepare_to_access_memory () override;
 300
 301   void done_accessing_memory () override;
 302
 303   int read_memory (CORE_ADDR memaddr, unsigned char *myaddr,
 304                    int len) override;
 305
 306   int write_memory (CORE_ADDR memaddr, const unsigned char *myaddr,
 307                     int len) override;
 308
 309   void look_up_symbols () override;
 310
 311   void request_interrupt () override;
 312
 313   bool supports_read_auxv () override;
 314
 315   int read_auxv (CORE_ADDR offset, unsigned char *myaddr,
 316                  unsigned int len) override;
 317
 318   bool supports_z_point_type (char z_type) override;
 319
 320   int insert_point (enum raw_bkpt_type type, CORE_ADDR addr,
 321                     int size, raw_breakpoint *bp) override;
 322
 323   int remove_point (enum raw_bkpt_type type, CORE_ADDR addr,
 324                     int size, raw_breakpoint *bp) override;
 325
 326   bool stopped_by_sw_breakpoint () override;
 327
 328   bool supports_stopped_by_sw_breakpoint () override;
 329
 330   bool stopped_by_hw_breakpoint () override;
 331
 332   bool supports_stopped_by_hw_breakpoint () override;
 333
 334   bool supports_hardware_single_step () override;
 335
 336   bool stopped_by_watchpoint () override;
 337
 338   CORE_ADDR stopped_data_address () override;
 339
 340   bool supports_read_offsets () override;
 341
 342   int read_offsets (CORE_ADDR *text, CORE_ADDR *data) override;
 343
 344   bool supports_get_tls_address () override;
 345
 346   int get_tls_address (thread_info *thread, CORE_ADDR offset,
 347                        CORE_ADDR load_module, CORE_ADDR *address) override;
 348 };
 349
 350 #define get_thread_lwp(thr) ((struct lwp_info *) (thread_target_data (thr)))
 351 #define get_lwp_thread(lwp) ((lwp)->thread)
 352
 353 /* This struct is recorded in the target_data field of struct thread_info.
 354
 355    On linux ``all_threads'' is keyed by the LWP ID, which we use as the
 356    GDB protocol representation of the thread ID.  Threads also have
 357    a "process ID" (poorly named) which is (presently) the same as the
 358    LWP ID.
 359
 360    There is also ``all_processes'' is keyed by the "overall process ID",
 361    which GNU/Linux calls tgid, "thread group ID".  */
 362
 363 struct lwp_info
 364 {
 365   /* Backlink to the parent object.  */
 366   struct thread_info *thread;
 367
 368   /* If this flag is set, the next SIGSTOP will be ignored (the
 369      process will be immediately resumed).  This means that either we
 370      sent the SIGSTOP to it ourselves and got some other pending event
 371      (so the SIGSTOP is still pending), or that we stopped the
 372      inferior implicitly via PTRACE_ATTACH and have not waited for it
 373      yet.  */
 374   int stop_expected;
 375
 376   /* When this is true, we shall not try to resume this thread, even
 377      if last_resume_kind isn't resume_stop.  */
 378   int suspended;
 379
 380   /* If this flag is set, the lwp is known to be stopped right now (stop
 381      event already received in a wait()).  */
 382   int stopped;
 383
 384   /* Signal whether we are in a SYSCALL_ENTRY or
 385      in a SYSCALL_RETURN event.
 386      Values:
 387      - TARGET_WAITKIND_SYSCALL_ENTRY
 388      - TARGET_WAITKIND_SYSCALL_RETURN */
 389   enum target_waitkind syscall_state;
 390
 391   /* When stopped is set, the last wait status recorded for this lwp.  */
 392   int last_status;
 393
 394   /* If WAITSTATUS->KIND != TARGET_WAITKIND_IGNORE, the waitstatus for
 395      this LWP's last event, to pass to GDB without any further
 396      processing.  This is used to store extended ptrace event
 397      information or exit status until it can be reported to GDB.  */
 398   struct target_waitstatus waitstatus;
 399
 400   /* A pointer to the fork child/parent relative.  Valid only while
 401      the parent fork event is not reported to higher layers.  Used to
 402      avoid wildcard vCont actions resuming a fork child before GDB is
 403      notified about the parent's fork event.  */
 404   struct lwp_info *fork_relative;
 405
 406   /* When stopped is set, this is where the lwp last stopped, with
 407      decr_pc_after_break already accounted for.  If the LWP is
 408      running, this is the address at which the lwp was resumed.  */
 409   CORE_ADDR stop_pc;
 410
 411   /* If this flag is set, STATUS_PENDING is a waitstatus that has not yet
 412      been reported.  */
 413   int status_pending_p;
 414   int status_pending;
 415
 416   /* The reason the LWP last stopped, if we need to track it
 417      (breakpoint, watchpoint, etc.)  */
 418   enum target_stop_reason stop_reason;
 419
 420   /* On architectures where it is possible to know the data address of
 421      a triggered watchpoint, STOPPED_DATA_ADDRESS is non-zero, and
 422      contains such data address.  Only valid if STOPPED_BY_WATCHPOINT
 423      is true.  */
 424   CORE_ADDR stopped_data_address;
 425
 426   /* If this is non-zero, it is a breakpoint to be reinserted at our next
 427      stop (SIGTRAP stops only).  */
 428   CORE_ADDR bp_reinsert;
 429
 430   /* If this flag is set, the last continue operation at the ptrace
 431      level on this process was a single-step.  */
 432   int stepping;
 433
 434   /* Range to single step within.  This is a copy of the step range
 435      passed along the last resume request.  See 'struct
 436      thread_resume'.  */
 437   CORE_ADDR step_range_start;   /* Inclusive */
 438   CORE_ADDR step_range_end;     /* Exclusive */
 439
 440   /* If this flag is set, we need to set the event request flags the
 441      next time we see this LWP stop.  */
 442   int must_set_ptrace_flags;
 443
 444   /* If this is non-zero, it points to a chain of signals which need to
 445      be delivered to this process.  */
 446   struct pending_signals *pending_signals;
 447
 448   /* A link used when resuming.  It is initialized from the resume request,
 449      and then processed and cleared in linux_resume_one_lwp.  */
 450   struct thread_resume *resume;
 451
 452   /* Information bout this lwp's fast tracepoint collection status (is it
 453      currently stopped in the jump pad, and if so, before or at/after the
 454      relocated instruction).  Normally, we won't care about this, but we will
 455      if a signal arrives to this lwp while it is collecting.  */
 456   fast_tpoint_collect_result collecting_fast_tracepoint;
 457
 458   /* If this is non-zero, it points to a chain of signals which need
 459      to be reported to GDB.  These were deferred because the thread
 460      was doing a fast tracepoint collect when they arrived.  */
 461   struct pending_signals *pending_signals_to_report;
 462
 463   /* When collecting_fast_tracepoint is first found to be 1, we insert
 464      a exit-jump-pad-quickly breakpoint.  This is it.  */
 465   struct breakpoint *exit_jump_pad_bkpt;
 466
 467 #ifdef USE_THREAD_DB
 468   int thread_known;
 469   /* The thread handle, used for e.g. TLS access.  Only valid if
 470      THREAD_KNOWN is set.  */
 471   td_thrhandle_t th;
 472
 473   /* The pthread_t handle.  */
 474   thread_t thread_handle;
 475 #endif
 476
 477   /* Arch-specific additions.  */
 478   struct arch_lwp_info *arch_private;
 479 };
 480
 481 int linux_pid_exe_is_elf_64_file (int pid, unsigned int *machine);
 482
 483 /* Attach to PTID.  Returns 0 on success, non-zero otherwise (an
 484    errno).  */
 485 int linux_attach_lwp (ptid_t ptid);
 486
 487 struct lwp_info *find_lwp_pid (ptid_t ptid);
 488 /* For linux_stop_lwp see nat/linux-nat.h.  */
 489
 490 #ifdef HAVE_LINUX_REGSETS
 491 void initialize_regsets_info (struct regsets_info *regsets_info);
 492 #endif
 493
 494 void initialize_low_arch (void);
 495
 496 void linux_set_pc_32bit (struct regcache *regcache, CORE_ADDR pc);
 497 CORE_ADDR linux_get_pc_32bit (struct regcache *regcache);
 498
 499 void linux_set_pc_64bit (struct regcache *regcache, CORE_ADDR pc);
 500 CORE_ADDR linux_get_pc_64bit (struct regcache *regcache);
 501
 502 /* From thread-db.c  */
 503 int thread_db_init (void);
 504 void thread_db_detach (struct process_info *);
 505 void thread_db_mourn (struct process_info *);
 506 int thread_db_handle_monitor_command (char *);
 507 int thread_db_get_tls_address (struct thread_info *thread, CORE_ADDR offset,
 508                                CORE_ADDR load_module, CORE_ADDR *address);
 509 int thread_db_look_up_one_symbol (const char *name, CORE_ADDR *addrp);
 510
 511 /* Called from linux-low.c when a clone event is detected.  Upon entry,
 512    both the clone and the parent should be stopped.  This function does
 513    whatever is required have the clone under thread_db's control.  */
 514
 515 void thread_db_notice_clone (struct thread_info *parent_thr, ptid_t child_ptid);
 516
 517 bool thread_db_thread_handle (ptid_t ptid, gdb_byte **handle, int *handle_len);
 518
 519 extern int have_ptrace_getregset;
 520
 521 /* Search for the value with type MATCH in the auxv vector with
 522    entries of length WORDSIZE bytes.  If found, store the value in
 523    *VALP and return 1.  If not found or if there is an error, return
 524    0.  */
 525
 526 int linux_get_auxv (int wordsize, CORE_ADDR match,
 527                     CORE_ADDR *valp);
 528
 529 /* Fetch the AT_HWCAP entry from the auxv vector, where entries are length
 530    WORDSIZE.  If no entry was found, return zero.  */
 531
 532 CORE_ADDR linux_get_hwcap (int wordsize);
 533
 534 /* Fetch the AT_HWCAP2 entry from the auxv vector, where entries are length
 535    WORDSIZE.  If no entry was found, return zero.  */
 536
 537 CORE_ADDR linux_get_hwcap2 (int wordsize);
 538
 539 #endif /* GDBSERVER_LINUX_LOW_H */