gdb/gdbserver/linux-low.h

   1 /* Internal interfaces for the GNU/Linux specific target code for gdbserver.
   2    Copyright (C) 2002-2019 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 };
  44
  45 /* The arch's regsets array initializer must be terminated with a NULL
  46    regset.  */
  47 #define NULL_REGSET \
  48   { 0, 0, 0, -1, (enum regset_type) -1, NULL, NULL }
  49
  50 struct regset_info
  51 {
  52   int get_request, set_request;
  53   /* If NT_TYPE isn't 0, it will be passed to ptrace as the 3rd
  54      argument and the 4th argument should be "const struct iovec *".  */
  55   int nt_type;
  56   int size;
  57   enum regset_type type;
  58   regset_fill_func fill_function;
  59   regset_store_func store_function;
  60 };
  61
  62 /* Aggregation of all the supported regsets of a given
  63    architecture/mode.  */
  64
  65 struct regsets_info
  66 {
  67   /* The regsets array.  */
  68   struct regset_info *regsets;
  69
  70   /* The number of regsets in the REGSETS array.  */
  71   int num_regsets;
  72
  73   /* If we get EIO on a regset, do not try it again.  Note the set of
  74      supported regsets may depend on processor mode on biarch
  75      machines.  This is a (lazily allocated) array holding one boolean
  76      byte (0/1) per regset, with each element corresponding to the
  77      regset in the REGSETS array above at the same offset.  */
  78   char *disabled_regsets;
  79 };
  80
  81 #endif
  82
  83 /* Mapping between the general-purpose registers in `struct user'
  84    format and GDB's register array layout.  */
  85
  86 struct usrregs_info
  87 {
  88   /* The number of registers accessible.  */
  89   int num_regs;
  90
  91   /* The registers map.  */
  92   int *regmap;
  93 };
  94
  95 /* All info needed to access an architecture/mode's registers.  */
  96
  97 struct regs_info
  98 {
  99   /* Regset support bitmap: 1 for registers that are transferred as a part
 100      of a regset, 0 for ones that need to be handled individually.  This
 101      can be NULL if all registers are transferred with regsets or regsets
 102      are not supported.  */
 103   unsigned char *regset_bitmap;
 104
 105   /* Info used when accessing registers with PTRACE_PEEKUSER /
 106      PTRACE_POKEUSER.  This can be NULL if all registers are
 107      transferred with regsets  .*/
 108   struct usrregs_info *usrregs;
 109
 110 #ifdef HAVE_LINUX_REGSETS
 111   /* Info used when accessing registers with regsets.  */
 112   struct regsets_info *regsets_info;
 113 #endif
 114 };
 115
 116 struct process_info_private
 117 {
 118   /* Arch-specific additions.  */
 119   struct arch_process_info *arch_private;
 120
 121   /* libthread_db-specific additions.  Not NULL if this process has loaded
 122      thread_db, and it is active.  */
 123   struct thread_db *thread_db;
 124
 125   /* &_r_debug.  0 if not yet determined.  -1 if no PT_DYNAMIC in Phdrs.  */
 126   CORE_ADDR r_debug;
 127 };
 128
 129 struct lwp_info;
 130
 131 struct linux_target_ops
 132 {
 133   /* Architecture-specific setup.  */
 134   void (*arch_setup) (void);
 135
 136   const struct regs_info *(*regs_info) (void);
 137   int (*cannot_fetch_register) (int);
 138
 139   /* Returns 0 if we can store the register, 1 if we can not
 140      store the register, and 2 if failure to store the register
 141      is acceptable.  */
 142   int (*cannot_store_register) (int);
 143
 144   /* Hook to fetch a register in some non-standard way.  Used for
 145      example by backends that have read-only registers with hardcoded
 146      values (e.g., IA64's gr0/fr0/fr1).  Returns true if register
 147      REGNO was supplied, false if not, and we should fallback to the
 148      standard ptrace methods.  */
 149   int (*fetch_register) (struct regcache *regcache, int regno);
 150
 151   CORE_ADDR (*get_pc) (struct regcache *regcache);
 152   void (*set_pc) (struct regcache *regcache, CORE_ADDR newpc);
 153
 154   /* See target.h for details.  */
 155   int (*breakpoint_kind_from_pc) (CORE_ADDR *pcptr);
 156
 157   /* See target.h for details.  */
 158   const gdb_byte *(*sw_breakpoint_from_kind) (int kind, int *size);
 159
 160   /* Find the next possible PCs after the current instruction executes.  */
 161   std::vector<CORE_ADDR> (*get_next_pcs) (struct regcache *regcache);
 162
 163   int decr_pc_after_break;
 164   int (*breakpoint_at) (CORE_ADDR pc);
 165
 166   /* Breakpoint and watchpoint related functions.  See target.h for
 167      comments.  */
 168   int (*supports_z_point_type) (char z_type);
 169   int (*insert_point) (enum raw_bkpt_type type, CORE_ADDR addr,
 170                        int size, struct raw_breakpoint *bp);
 171   int (*remove_point) (enum raw_bkpt_type type, CORE_ADDR addr,
 172                        int size, struct raw_breakpoint *bp);
 173
 174   int (*stopped_by_watchpoint) (void);
 175   CORE_ADDR (*stopped_data_address) (void);
 176
 177   /* Hooks to reformat register data for PEEKUSR/POKEUSR (in particular
 178      for registers smaller than an xfer unit).  */
 179   void (*collect_ptrace_register) (struct regcache *regcache,
 180                                    int regno, char *buf);
 181   void (*supply_ptrace_register) (struct regcache *regcache,
 182                                   int regno, const char *buf);
 183
 184   /* Hook to convert from target format to ptrace format and back.
 185      Returns true if any conversion was done; false otherwise.
 186      If DIRECTION is 1, then copy from INF to NATIVE.
 187      If DIRECTION is 0, copy from NATIVE to INF.  */
 188   int (*siginfo_fixup) (siginfo_t *native, gdb_byte *inf, int direction);
 189
 190   /* Hook to call when a new process is created or attached to.
 191      If extra per-process architecture-specific data is needed,
 192      allocate it here.  */
 193   struct arch_process_info * (*new_process) (void);
 194
 195   /* Hook to call when a process is being deleted.  If extra per-process
 196      architecture-specific data is needed, delete it here.  */
 197   void (*delete_process) (struct arch_process_info *info);
 198
 199   /* Hook to call when a new thread is detected.
 200      If extra per-thread architecture-specific data is needed,
 201      allocate it here.  */
 202   void (*new_thread) (struct lwp_info *);
 203
 204   /* Hook to call when a thread is being deleted.  If extra per-thread
 205      architecture-specific data is needed, delete it here.  */
 206   void (*delete_thread) (struct arch_lwp_info *);
 207
 208   /* Hook to call, if any, when a new fork is attached.  */
 209   void (*new_fork) (struct process_info *parent, struct process_info *child);
 210
 211   /* Hook to call prior to resuming a thread.  */
 212   void (*prepare_to_resume) (struct lwp_info *);
 213
 214   /* Hook to support target specific qSupported.  */
 215   void (*process_qsupported) (char **, int count);
 216
 217   /* Returns true if the low target supports tracepoints.  */
 218   int (*supports_tracepoints) (void);
 219
 220   /* Fill ADDRP with the thread area address of LWPID.  Returns 0 on
 221      success, -1 on failure.  */
 222   int (*get_thread_area) (int lwpid, CORE_ADDR *addrp);
 223
 224   /* Install a fast tracepoint jump pad.  See target.h for
 225      comments.  */
 226   int (*install_fast_tracepoint_jump_pad) (CORE_ADDR tpoint, CORE_ADDR tpaddr,
 227                                            CORE_ADDR collector,
 228                                            CORE_ADDR lockaddr,
 229                                            ULONGEST orig_size,
 230                                            CORE_ADDR *jump_entry,
 231                                            CORE_ADDR *trampoline,
 232                                            ULONGEST *trampoline_size,
 233                                            unsigned char *jjump_pad_insn,
 234                                            ULONGEST *jjump_pad_insn_size,
 235                                            CORE_ADDR *adjusted_insn_addr,
 236                                            CORE_ADDR *adjusted_insn_addr_end,
 237                                            char *err);
 238
 239   /* Return the bytecode operations vector for the current inferior.
 240      Returns NULL if bytecode compilation is not supported.  */
 241   struct emit_ops *(*emit_ops) (void);
 242
 243   /* Return the minimum length of an instruction that can be safely overwritten
 244      for use as a fast tracepoint.  */
 245   int (*get_min_fast_tracepoint_insn_len) (void);
 246
 247   /* Returns true if the low target supports range stepping.  */
 248   int (*supports_range_stepping) (void);
 249
 250   /* See target.h.  */
 251   int (*breakpoint_kind_from_current_state) (CORE_ADDR *pcptr);
 252
 253   /* See target.h.  */
 254   int (*supports_hardware_single_step) (void);
 255
 256   /* Fill *SYSNO with the syscall nr trapped.  Only to be called when
 257      inferior is stopped due to SYSCALL_SIGTRAP.  */
 258   void (*get_syscall_trapinfo) (struct regcache *regcache, int *sysno);
 259
 260   /* See target.h.  */
 261   int (*get_ipa_tdesc_idx) (void);
 262 };
 263
 264 extern struct linux_target_ops the_low_target;
 265
 266 #define get_thread_lwp(thr) ((struct lwp_info *) (thread_target_data (thr)))
 267 #define get_lwp_thread(lwp) ((lwp)->thread)
 268
 269 /* This struct is recorded in the target_data field of struct thread_info.
 270
 271    On linux ``all_threads'' is keyed by the LWP ID, which we use as the
 272    GDB protocol representation of the thread ID.  Threads also have
 273    a "process ID" (poorly named) which is (presently) the same as the
 274    LWP ID.
 275
 276    There is also ``all_processes'' is keyed by the "overall process ID",
 277    which GNU/Linux calls tgid, "thread group ID".  */
 278
 279 struct lwp_info
 280 {
 281   /* Backlink to the parent object.  */
 282   struct thread_info *thread;
 283
 284   /* If this flag is set, the next SIGSTOP will be ignored (the
 285      process will be immediately resumed).  This means that either we
 286      sent the SIGSTOP to it ourselves and got some other pending event
 287      (so the SIGSTOP is still pending), or that we stopped the
 288      inferior implicitly via PTRACE_ATTACH and have not waited for it
 289      yet.  */
 290   int stop_expected;
 291
 292   /* When this is true, we shall not try to resume this thread, even
 293      if last_resume_kind isn't resume_stop.  */
 294   int suspended;
 295
 296   /* If this flag is set, the lwp is known to be stopped right now (stop
 297      event already received in a wait()).  */
 298   int stopped;
 299
 300   /* Signal whether we are in a SYSCALL_ENTRY or
 301      in a SYSCALL_RETURN event.
 302      Values:
 303      - TARGET_WAITKIND_SYSCALL_ENTRY
 304      - TARGET_WAITKIND_SYSCALL_RETURN */
 305   enum target_waitkind syscall_state;
 306
 307   /* When stopped is set, the last wait status recorded for this lwp.  */
 308   int last_status;
 309
 310   /* If WAITSTATUS->KIND != TARGET_WAITKIND_IGNORE, the waitstatus for
 311      this LWP's last event, to pass to GDB without any further
 312      processing.  This is used to store extended ptrace event
 313      information or exit status until it can be reported to GDB.  */
 314   struct target_waitstatus waitstatus;
 315
 316   /* A pointer to the fork child/parent relative.  Valid only while
 317      the parent fork event is not reported to higher layers.  Used to
 318      avoid wildcard vCont actions resuming a fork child before GDB is
 319      notified about the parent's fork event.  */
 320   struct lwp_info *fork_relative;
 321
 322   /* When stopped is set, this is where the lwp last stopped, with
 323      decr_pc_after_break already accounted for.  If the LWP is
 324      running, this is the address at which the lwp was resumed.  */
 325   CORE_ADDR stop_pc;
 326
 327   /* If this flag is set, STATUS_PENDING is a waitstatus that has not yet
 328      been reported.  */
 329   int status_pending_p;
 330   int status_pending;
 331
 332   /* The reason the LWP last stopped, if we need to track it
 333      (breakpoint, watchpoint, etc.)  */
 334   enum target_stop_reason stop_reason;
 335
 336   /* On architectures where it is possible to know the data address of
 337      a triggered watchpoint, STOPPED_DATA_ADDRESS is non-zero, and
 338      contains such data address.  Only valid if STOPPED_BY_WATCHPOINT
 339      is true.  */
 340   CORE_ADDR stopped_data_address;
 341
 342   /* If this is non-zero, it is a breakpoint to be reinserted at our next
 343      stop (SIGTRAP stops only).  */
 344   CORE_ADDR bp_reinsert;
 345
 346   /* If this flag is set, the last continue operation at the ptrace
 347      level on this process was a single-step.  */
 348   int stepping;
 349
 350   /* Range to single step within.  This is a copy of the step range
 351      passed along the last resume request.  See 'struct
 352      thread_resume'.  */
 353   CORE_ADDR step_range_start;   /* Inclusive */
 354   CORE_ADDR step_range_end;     /* Exclusive */
 355
 356   /* If this flag is set, we need to set the event request flags the
 357      next time we see this LWP stop.  */
 358   int must_set_ptrace_flags;
 359
 360   /* If this is non-zero, it points to a chain of signals which need to
 361      be delivered to this process.  */
 362   struct pending_signals *pending_signals;
 363
 364   /* A link used when resuming.  It is initialized from the resume request,
 365      and then processed and cleared in linux_resume_one_lwp.  */
 366   struct thread_resume *resume;
 367
 368   /* Information bout this lwp's fast tracepoint collection status (is it
 369      currently stopped in the jump pad, and if so, before or at/after the
 370      relocated instruction).  Normally, we won't care about this, but we will
 371      if a signal arrives to this lwp while it is collecting.  */
 372   fast_tpoint_collect_result collecting_fast_tracepoint;
 373
 374   /* If this is non-zero, it points to a chain of signals which need
 375      to be reported to GDB.  These were deferred because the thread
 376      was doing a fast tracepoint collect when they arrived.  */
 377   struct pending_signals *pending_signals_to_report;
 378
 379   /* When collecting_fast_tracepoint is first found to be 1, we insert
 380      a exit-jump-pad-quickly breakpoint.  This is it.  */
 381   struct breakpoint *exit_jump_pad_bkpt;
 382
 383 #ifdef USE_THREAD_DB
 384   int thread_known;
 385   /* The thread handle, used for e.g. TLS access.  Only valid if
 386      THREAD_KNOWN is set.  */
 387   td_thrhandle_t th;
 388
 389   /* The pthread_t handle.  */
 390   thread_t thread_handle;
 391 #endif
 392
 393   /* Arch-specific additions.  */
 394   struct arch_lwp_info *arch_private;
 395 };
 396
 397 int linux_pid_exe_is_elf_64_file (int pid, unsigned int *machine);
 398
 399 /* Attach to PTID.  Returns 0 on success, non-zero otherwise (an
 400    errno).  */
 401 int linux_attach_lwp (ptid_t ptid);
 402
 403 struct lwp_info *find_lwp_pid (ptid_t ptid);
 404 /* For linux_stop_lwp see nat/linux-nat.h.  */
 405
 406 #ifdef HAVE_LINUX_REGSETS
 407 void initialize_regsets_info (struct regsets_info *regsets_info);
 408 #endif
 409
 410 void initialize_low_arch (void);
 411
 412 void linux_set_pc_32bit (struct regcache *regcache, CORE_ADDR pc);
 413 CORE_ADDR linux_get_pc_32bit (struct regcache *regcache);
 414
 415 void linux_set_pc_64bit (struct regcache *regcache, CORE_ADDR pc);
 416 CORE_ADDR linux_get_pc_64bit (struct regcache *regcache);
 417
 418 /* From thread-db.c  */
 419 int thread_db_init (void);
 420 void thread_db_detach (struct process_info *);
 421 void thread_db_mourn (struct process_info *);
 422 int thread_db_handle_monitor_command (char *);
 423 int thread_db_get_tls_address (struct thread_info *thread, CORE_ADDR offset,
 424                                CORE_ADDR load_module, CORE_ADDR *address);
 425 int thread_db_look_up_one_symbol (const char *name, CORE_ADDR *addrp);
 426
 427 /* Called from linux-low.c when a clone event is detected.  Upon entry,
 428    both the clone and the parent should be stopped.  This function does
 429    whatever is required have the clone under thread_db's control.  */
 430
 431 void thread_db_notice_clone (struct thread_info *parent_thr, ptid_t child_ptid);
 432
 433 bool thread_db_thread_handle (ptid_t ptid, gdb_byte **handle, int *handle_len);
 434
 435 extern int have_ptrace_getregset;
 436
 437 #endif /* GDBSERVER_LINUX_LOW_H */