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
 304 #define get_thread_lwp(thr) ((struct lwp_info *) (thread_target_data (thr)))
 305 #define get_lwp_thread(lwp) ((lwp)->thread)
 306
 307 /* This struct is recorded in the target_data field of struct thread_info.
 308
 309    On linux ``all_threads'' is keyed by the LWP ID, which we use as the
 310    GDB protocol representation of the thread ID.  Threads also have
 311    a "process ID" (poorly named) which is (presently) the same as the
 312    LWP ID.
 313
 314    There is also ``all_processes'' is keyed by the "overall process ID",
 315    which GNU/Linux calls tgid, "thread group ID".  */
 316
 317 struct lwp_info
 318 {
 319   /* Backlink to the parent object.  */
 320   struct thread_info *thread;
 321
 322   /* If this flag is set, the next SIGSTOP will be ignored (the
 323      process will be immediately resumed).  This means that either we
 324      sent the SIGSTOP to it ourselves and got some other pending event
 325      (so the SIGSTOP is still pending), or that we stopped the
 326      inferior implicitly via PTRACE_ATTACH and have not waited for it
 327      yet.  */
 328   int stop_expected;
 329
 330   /* When this is true, we shall not try to resume this thread, even
 331      if last_resume_kind isn't resume_stop.  */
 332   int suspended;
 333
 334   /* If this flag is set, the lwp is known to be stopped right now (stop
 335      event already received in a wait()).  */
 336   int stopped;
 337
 338   /* Signal whether we are in a SYSCALL_ENTRY or
 339      in a SYSCALL_RETURN event.
 340      Values:
 341      - TARGET_WAITKIND_SYSCALL_ENTRY
 342      - TARGET_WAITKIND_SYSCALL_RETURN */
 343   enum target_waitkind syscall_state;
 344
 345   /* When stopped is set, the last wait status recorded for this lwp.  */
 346   int last_status;
 347
 348   /* If WAITSTATUS->KIND != TARGET_WAITKIND_IGNORE, the waitstatus for
 349      this LWP's last event, to pass to GDB without any further
 350      processing.  This is used to store extended ptrace event
 351      information or exit status until it can be reported to GDB.  */
 352   struct target_waitstatus waitstatus;
 353
 354   /* A pointer to the fork child/parent relative.  Valid only while
 355      the parent fork event is not reported to higher layers.  Used to
 356      avoid wildcard vCont actions resuming a fork child before GDB is
 357      notified about the parent's fork event.  */
 358   struct lwp_info *fork_relative;
 359
 360   /* When stopped is set, this is where the lwp last stopped, with
 361      decr_pc_after_break already accounted for.  If the LWP is
 362      running, this is the address at which the lwp was resumed.  */
 363   CORE_ADDR stop_pc;
 364
 365   /* If this flag is set, STATUS_PENDING is a waitstatus that has not yet
 366      been reported.  */
 367   int status_pending_p;
 368   int status_pending;
 369
 370   /* The reason the LWP last stopped, if we need to track it
 371      (breakpoint, watchpoint, etc.)  */
 372   enum target_stop_reason stop_reason;
 373
 374   /* On architectures where it is possible to know the data address of
 375      a triggered watchpoint, STOPPED_DATA_ADDRESS is non-zero, and
 376      contains such data address.  Only valid if STOPPED_BY_WATCHPOINT
 377      is true.  */
 378   CORE_ADDR stopped_data_address;
 379
 380   /* If this is non-zero, it is a breakpoint to be reinserted at our next
 381      stop (SIGTRAP stops only).  */
 382   CORE_ADDR bp_reinsert;
 383
 384   /* If this flag is set, the last continue operation at the ptrace
 385      level on this process was a single-step.  */
 386   int stepping;
 387
 388   /* Range to single step within.  This is a copy of the step range
 389      passed along the last resume request.  See 'struct
 390      thread_resume'.  */
 391   CORE_ADDR step_range_start;   /* Inclusive */
 392   CORE_ADDR step_range_end;     /* Exclusive */
 393
 394   /* If this flag is set, we need to set the event request flags the
 395      next time we see this LWP stop.  */
 396   int must_set_ptrace_flags;
 397
 398   /* If this is non-zero, it points to a chain of signals which need to
 399      be delivered to this process.  */
 400   struct pending_signals *pending_signals;
 401
 402   /* A link used when resuming.  It is initialized from the resume request,
 403      and then processed and cleared in linux_resume_one_lwp.  */
 404   struct thread_resume *resume;
 405
 406   /* Information bout this lwp's fast tracepoint collection status (is it
 407      currently stopped in the jump pad, and if so, before or at/after the
 408      relocated instruction).  Normally, we won't care about this, but we will
 409      if a signal arrives to this lwp while it is collecting.  */
 410   fast_tpoint_collect_result collecting_fast_tracepoint;
 411
 412   /* If this is non-zero, it points to a chain of signals which need
 413      to be reported to GDB.  These were deferred because the thread
 414      was doing a fast tracepoint collect when they arrived.  */
 415   struct pending_signals *pending_signals_to_report;
 416
 417   /* When collecting_fast_tracepoint is first found to be 1, we insert
 418      a exit-jump-pad-quickly breakpoint.  This is it.  */
 419   struct breakpoint *exit_jump_pad_bkpt;
 420
 421 #ifdef USE_THREAD_DB
 422   int thread_known;
 423   /* The thread handle, used for e.g. TLS access.  Only valid if
 424      THREAD_KNOWN is set.  */
 425   td_thrhandle_t th;
 426
 427   /* The pthread_t handle.  */
 428   thread_t thread_handle;
 429 #endif
 430
 431   /* Arch-specific additions.  */
 432   struct arch_lwp_info *arch_private;
 433 };
 434
 435 int linux_pid_exe_is_elf_64_file (int pid, unsigned int *machine);
 436
 437 /* Attach to PTID.  Returns 0 on success, non-zero otherwise (an
 438    errno).  */
 439 int linux_attach_lwp (ptid_t ptid);
 440
 441 struct lwp_info *find_lwp_pid (ptid_t ptid);
 442 /* For linux_stop_lwp see nat/linux-nat.h.  */
 443
 444 #ifdef HAVE_LINUX_REGSETS
 445 void initialize_regsets_info (struct regsets_info *regsets_info);
 446 #endif
 447
 448 void initialize_low_arch (void);
 449
 450 void linux_set_pc_32bit (struct regcache *regcache, CORE_ADDR pc);
 451 CORE_ADDR linux_get_pc_32bit (struct regcache *regcache);
 452
 453 void linux_set_pc_64bit (struct regcache *regcache, CORE_ADDR pc);
 454 CORE_ADDR linux_get_pc_64bit (struct regcache *regcache);
 455
 456 /* From thread-db.c  */
 457 int thread_db_init (void);
 458 void thread_db_detach (struct process_info *);
 459 void thread_db_mourn (struct process_info *);
 460 int thread_db_handle_monitor_command (char *);
 461 int thread_db_get_tls_address (struct thread_info *thread, CORE_ADDR offset,
 462                                CORE_ADDR load_module, CORE_ADDR *address);
 463 int thread_db_look_up_one_symbol (const char *name, CORE_ADDR *addrp);
 464
 465 /* Called from linux-low.c when a clone event is detected.  Upon entry,
 466    both the clone and the parent should be stopped.  This function does
 467    whatever is required have the clone under thread_db's control.  */
 468
 469 void thread_db_notice_clone (struct thread_info *parent_thr, ptid_t child_ptid);
 470
 471 bool thread_db_thread_handle (ptid_t ptid, gdb_byte **handle, int *handle_len);
 472
 473 extern int have_ptrace_getregset;
 474
 475 /* Search for the value with type MATCH in the auxv vector with
 476    entries of length WORDSIZE bytes.  If found, store the value in
 477    *VALP and return 1.  If not found or if there is an error, return
 478    0.  */
 479
 480 int linux_get_auxv (int wordsize, CORE_ADDR match,
 481                     CORE_ADDR *valp);
 482
 483 /* Fetch the AT_HWCAP entry from the auxv vector, where entries are length
 484    WORDSIZE.  If no entry was found, return zero.  */
 485
 486 CORE_ADDR linux_get_hwcap (int wordsize);
 487
 488 /* Fetch the AT_HWCAP2 entry from the auxv vector, where entries are length
 489    WORDSIZE.  If no entry was found, return zero.  */
 490
 491 CORE_ADDR linux_get_hwcap2 (int wordsize);
 492
 493 #endif /* GDBSERVER_LINUX_LOW_H */