gdb/gdbserver/linux-low.h

   1 /* Internal interfaces for the GNU/Linux specific target code for gdbserver.
   2    Copyright (C) 2002-2018 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 #include "nat/linux-nat.h"
  20 #include "nat/gdb_thread_db.h"
  21 #include <signal.h>
  22
  23 #include "gdbthread.h"
  24 #include "gdb_proc_service.h"
  25
  26 /* Included for ptrace type definitions.  */
  27 #include "nat/linux-ptrace.h"
  28 #include "target/waitstatus.h" /* For enum target_stop_reason.  */
  29 #include "tracepoint.h"
  30
  31 #define PTRACE_XFER_TYPE long
  32
  33 #ifdef HAVE_LINUX_REGSETS
  34 typedef void (*regset_fill_func) (struct regcache *, void *);
  35 typedef void (*regset_store_func) (struct regcache *, const void *);
  36 enum regset_type {
  37   GENERAL_REGS,
  38   FP_REGS,
  39   EXTENDED_REGS,
  40 };
  41
  42 /* The arch's regsets array initializer must be terminated with a NULL
  43    regset.  */
  44 #define NULL_REGSET \
  45   { 0, 0, 0, -1, (enum regset_type) -1, NULL, NULL }
  46
  47 struct regset_info
  48 {
  49   int get_request, set_request;
  50   /* If NT_TYPE isn't 0, it will be passed to ptrace as the 3rd
  51      argument and the 4th argument should be "const struct iovec *".  */
  52   int nt_type;
  53   int size;
  54   enum regset_type type;
  55   regset_fill_func fill_function;
  56   regset_store_func store_function;
  57 };
  58
  59 /* Aggregation of all the supported regsets of a given
  60    architecture/mode.  */
  61
  62 struct regsets_info
  63 {
  64   /* The regsets array.  */
  65   struct regset_info *regsets;
  66
  67   /* The number of regsets in the REGSETS array.  */
  68   int num_regsets;
  69
  70   /* If we get EIO on a regset, do not try it again.  Note the set of
  71      supported regsets may depend on processor mode on biarch
  72      machines.  This is a (lazily allocated) array holding one boolean
  73      byte (0/1) per regset, with each element corresponding to the
  74      regset in the REGSETS array above at the same offset.  */
  75   char *disabled_regsets;
  76 };
  77
  78 #endif
  79
  80 /* Mapping between the general-purpose registers in `struct user'
  81    format and GDB's register array layout.  */
  82
  83 struct usrregs_info
  84 {
  85   /* The number of registers accessible.  */
  86   int num_regs;
  87
  88   /* The registers map.  */
  89   int *regmap;
  90 };
  91
  92 /* All info needed to access an architecture/mode's registers.  */
  93
  94 struct regs_info
  95 {
  96   /* Regset support bitmap: 1 for registers that are transferred as a part
  97      of a regset, 0 for ones that need to be handled individually.  This
  98      can be NULL if all registers are transferred with regsets or regsets
  99      are not supported.  */
 100   unsigned char *regset_bitmap;
 101
 102   /* Info used when accessing registers with PTRACE_PEEKUSER /
 103      PTRACE_POKEUSER.  This can be NULL if all registers are
 104      transferred with regsets  .*/
 105   struct usrregs_info *usrregs;
 106
 107 #ifdef HAVE_LINUX_REGSETS
 108   /* Info used when accessing registers with regsets.  */
 109   struct regsets_info *regsets_info;
 110 #endif
 111 };
 112
 113 struct process_info_private
 114 {
 115   /* Arch-specific additions.  */
 116   struct arch_process_info *arch_private;
 117
 118   /* libthread_db-specific additions.  Not NULL if this process has loaded
 119      thread_db, and it is active.  */
 120   struct thread_db *thread_db;
 121
 122   /* &_r_debug.  0 if not yet determined.  -1 if no PT_DYNAMIC in Phdrs.  */
 123   CORE_ADDR r_debug;
 124 };
 125
 126 struct lwp_info;
 127
 128 struct linux_target_ops
 129 {
 130   /* Architecture-specific setup.  */
 131   void (*arch_setup) (void);
 132
 133   const struct regs_info *(*regs_info) (void);
 134   int (*cannot_fetch_register) (int);
 135
 136   /* Returns 0 if we can store the register, 1 if we can not
 137      store the register, and 2 if failure to store the register
 138      is acceptable.  */
 139   int (*cannot_store_register) (int);
 140
 141   /* Hook to fetch a register in some non-standard way.  Used for
 142      example by backends that have read-only registers with hardcoded
 143      values (e.g., IA64's gr0/fr0/fr1).  Returns true if register
 144      REGNO was supplied, false if not, and we should fallback to the
 145      standard ptrace methods.  */
 146   int (*fetch_register) (struct regcache *regcache, int regno);
 147
 148   CORE_ADDR (*get_pc) (struct regcache *regcache);
 149   void (*set_pc) (struct regcache *regcache, CORE_ADDR newpc);
 150
 151   /* See target.h for details.  */
 152   int (*breakpoint_kind_from_pc) (CORE_ADDR *pcptr);
 153
 154   /* See target.h for details.  */
 155   const gdb_byte *(*sw_breakpoint_from_kind) (int kind, int *size);
 156
 157   /* Find the next possible PCs after the current instruction executes.  */
 158   std::vector<CORE_ADDR> (*get_next_pcs) (struct regcache *regcache);
 159
 160   int decr_pc_after_break;
 161   int (*breakpoint_at) (CORE_ADDR pc);
 162
 163   /* Breakpoint and watchpoint related functions.  See target.h for
 164      comments.  */
 165   int (*supports_z_point_type) (char z_type);
 166   int (*insert_point) (enum raw_bkpt_type type, CORE_ADDR addr,
 167                        int size, struct raw_breakpoint *bp);
 168   int (*remove_point) (enum raw_bkpt_type type, CORE_ADDR addr,
 169                        int size, struct raw_breakpoint *bp);
 170
 171   int (*stopped_by_watchpoint) (void);
 172   CORE_ADDR (*stopped_data_address) (void);
 173
 174   /* Hooks to reformat register data for PEEKUSR/POKEUSR (in particular
 175      for registers smaller than an xfer unit).  */
 176   void (*collect_ptrace_register) (struct regcache *regcache,
 177                                    int regno, char *buf);
 178   void (*supply_ptrace_register) (struct regcache *regcache,
 179                                   int regno, const char *buf);
 180
 181   /* Hook to convert from target format to ptrace format and back.
 182      Returns true if any conversion was done; false otherwise.
 183      If DIRECTION is 1, then copy from INF to NATIVE.
 184      If DIRECTION is 0, copy from NATIVE to INF.  */
 185   int (*siginfo_fixup) (siginfo_t *native, gdb_byte *inf, int direction);
 186
 187   /* Hook to call when a new process is created or attached to.
 188      If extra per-process architecture-specific data is needed,
 189      allocate it here.  */
 190   struct arch_process_info * (*new_process) (void);
 191
 192   /* Hook to call when a process is being deleted.  If extra per-process
 193      architecture-specific data is needed, delete it here.  */
 194   void (*delete_process) (struct arch_process_info *info);
 195
 196   /* Hook to call when a new thread is detected.
 197      If extra per-thread architecture-specific data is needed,
 198      allocate it here.  */
 199   void (*new_thread) (struct lwp_info *);
 200
 201   /* Hook to call when a thread is being deleted.  If extra per-thread
 202      architecture-specific data is needed, delete it here.  */
 203   void (*delete_thread) (struct arch_lwp_info *);
 204
 205   /* Hook to call, if any, when a new fork is attached.  */
 206   void (*new_fork) (struct process_info *parent, struct process_info *child);
 207
 208   /* Hook to call prior to resuming a thread.  */
 209   void (*prepare_to_resume) (struct lwp_info *);
 210
 211   /* Hook to support target specific qSupported.  */
 212   void (*process_qsupported) (char **, int count);
 213
 214   /* Returns true if the low target supports tracepoints.  */
 215   int (*supports_tracepoints) (void);
 216
 217   /* Fill ADDRP with the thread area address of LWPID.  Returns 0 on
 218      success, -1 on failure.  */
 219   int (*get_thread_area) (int lwpid, CORE_ADDR *addrp);
 220
 221   /* Install a fast tracepoint jump pad.  See target.h for
 222      comments.  */
 223   int (*install_fast_tracepoint_jump_pad) (CORE_ADDR tpoint, CORE_ADDR tpaddr,
 224                                            CORE_ADDR collector,
 225                                            CORE_ADDR lockaddr,
 226                                            ULONGEST orig_size,
 227                                            CORE_ADDR *jump_entry,
 228                                            CORE_ADDR *trampoline,
 229                                            ULONGEST *trampoline_size,
 230                                            unsigned char *jjump_pad_insn,
 231                                            ULONGEST *jjump_pad_insn_size,
 232                                            CORE_ADDR *adjusted_insn_addr,
 233                                            CORE_ADDR *adjusted_insn_addr_end,
 234                                            char *err);
 235
 236   /* Return the bytecode operations vector for the current inferior.
 237      Returns NULL if bytecode compilation is not supported.  */
 238   struct emit_ops *(*emit_ops) (void);
 239
 240   /* Return the minimum length of an instruction that can be safely overwritten
 241      for use as a fast tracepoint.  */
 242   int (*get_min_fast_tracepoint_insn_len) (void);
 243
 244   /* Returns true if the low target supports range stepping.  */
 245   int (*supports_range_stepping) (void);
 246
 247   /* See target.h.  */
 248   int (*breakpoint_kind_from_current_state) (CORE_ADDR *pcptr);
 249
 250   /* See target.h.  */
 251   int (*supports_hardware_single_step) (void);
 252
 253   /* Fill *SYSNO with the syscall nr trapped.  Only to be called when
 254      inferior is stopped due to SYSCALL_SIGTRAP.  */
 255   void (*get_syscall_trapinfo) (struct regcache *regcache, int *sysno);
 256
 257   /* See target.h.  */
 258   int (*get_ipa_tdesc_idx) (void);
 259 };
 260
 261 extern struct linux_target_ops the_low_target;
 262
 263 #define get_thread_lwp(thr) ((struct lwp_info *) (thread_target_data (thr)))
 264 #define get_lwp_thread(lwp) ((lwp)->thread)
 265
 266 /* This struct is recorded in the target_data field of struct thread_info.
 267
 268    On linux ``all_threads'' is keyed by the LWP ID, which we use as the
 269    GDB protocol representation of the thread ID.  Threads also have
 270    a "process ID" (poorly named) which is (presently) the same as the
 271    LWP ID.
 272
 273    There is also ``all_processes'' is keyed by the "overall process ID",
 274    which GNU/Linux calls tgid, "thread group ID".  */
 275
 276 struct lwp_info
 277 {
 278   /* Backlink to the parent object.  */
 279   struct thread_info *thread;
 280
 281   /* If this flag is set, the next SIGSTOP will be ignored (the
 282      process will be immediately resumed).  This means that either we
 283      sent the SIGSTOP to it ourselves and got some other pending event
 284      (so the SIGSTOP is still pending), or that we stopped the
 285      inferior implicitly via PTRACE_ATTACH and have not waited for it
 286      yet.  */
 287   int stop_expected;
 288
 289   /* When this is true, we shall not try to resume this thread, even
 290      if last_resume_kind isn't resume_stop.  */
 291   int suspended;
 292
 293   /* If this flag is set, the lwp is known to be stopped right now (stop
 294      event already received in a wait()).  */
 295   int stopped;
 296
 297   /* Signal whether we are in a SYSCALL_ENTRY or
 298      in a SYSCALL_RETURN event.
 299      Values:
 300      - TARGET_WAITKIND_SYSCALL_ENTRY
 301      - TARGET_WAITKIND_SYSCALL_RETURN */
 302   enum target_waitkind syscall_state;
 303
 304   /* When stopped is set, the last wait status recorded for this lwp.  */
 305   int last_status;
 306
 307   /* If WAITSTATUS->KIND != TARGET_WAITKIND_IGNORE, the waitstatus for
 308      this LWP's last event, to pass to GDB without any further
 309      processing.  This is used to store extended ptrace event
 310      information or exit status until it can be reported to GDB.  */
 311   struct target_waitstatus waitstatus;
 312
 313   /* A pointer to the fork child/parent relative.  Valid only while
 314      the parent fork event is not reported to higher layers.  Used to
 315      avoid wildcard vCont actions resuming a fork child before GDB is
 316      notified about the parent's fork event.  */
 317   struct lwp_info *fork_relative;
 318
 319   /* When stopped is set, this is where the lwp last stopped, with
 320      decr_pc_after_break already accounted for.  If the LWP is
 321      running, this is the address at which the lwp was resumed.  */
 322   CORE_ADDR stop_pc;
 323
 324   /* If this flag is set, STATUS_PENDING is a waitstatus that has not yet
 325      been reported.  */
 326   int status_pending_p;
 327   int status_pending;
 328
 329   /* The reason the LWP last stopped, if we need to track it
 330      (breakpoint, watchpoint, etc.)  */
 331   enum target_stop_reason stop_reason;
 332
 333   /* On architectures where it is possible to know the data address of
 334      a triggered watchpoint, STOPPED_DATA_ADDRESS is non-zero, and
 335      contains such data address.  Only valid if STOPPED_BY_WATCHPOINT
 336      is true.  */
 337   CORE_ADDR stopped_data_address;
 338
 339   /* If this is non-zero, it is a breakpoint to be reinserted at our next
 340      stop (SIGTRAP stops only).  */
 341   CORE_ADDR bp_reinsert;
 342
 343   /* If this flag is set, the last continue operation at the ptrace
 344      level on this process was a single-step.  */
 345   int stepping;
 346
 347   /* Range to single step within.  This is a copy of the step range
 348      passed along the last resume request.  See 'struct
 349      thread_resume'.  */
 350   CORE_ADDR step_range_start;   /* Inclusive */
 351   CORE_ADDR step_range_end;     /* Exclusive */
 352
 353   /* If this flag is set, we need to set the event request flags the
 354      next time we see this LWP stop.  */
 355   int must_set_ptrace_flags;
 356
 357   /* If this is non-zero, it points to a chain of signals which need to
 358      be delivered to this process.  */
 359   struct pending_signals *pending_signals;
 360
 361   /* A link used when resuming.  It is initialized from the resume request,
 362      and then processed and cleared in linux_resume_one_lwp.  */
 363   struct thread_resume *resume;
 364
 365   /* Information bout this lwp's fast tracepoint collection status (is it
 366      currently stopped in the jump pad, and if so, before or at/after the
 367      relocated instruction).  Normally, we won't care about this, but we will
 368      if a signal arrives to this lwp while it is collecting.  */
 369   fast_tpoint_collect_result collecting_fast_tracepoint;
 370
 371   /* If this is non-zero, it points to a chain of signals which need
 372      to be reported to GDB.  These were deferred because the thread
 373      was doing a fast tracepoint collect when they arrived.  */
 374   struct pending_signals *pending_signals_to_report;
 375
 376   /* When collecting_fast_tracepoint is first found to be 1, we insert
 377      a exit-jump-pad-quickly breakpoint.  This is it.  */
 378   struct breakpoint *exit_jump_pad_bkpt;
 379
 380 #ifdef USE_THREAD_DB
 381   int thread_known;
 382   /* The thread handle, used for e.g. TLS access.  Only valid if
 383      THREAD_KNOWN is set.  */
 384   td_thrhandle_t th;
 385
 386   /* The pthread_t handle.  */
 387   thread_t thread_handle;
 388 #endif
 389
 390   /* Arch-specific additions.  */
 391   struct arch_lwp_info *arch_private;
 392 };
 393
 394 int linux_pid_exe_is_elf_64_file (int pid, unsigned int *machine);
 395
 396 /* Attach to PTID.  Returns 0 on success, non-zero otherwise (an
 397    errno).  */
 398 int linux_attach_lwp (ptid_t ptid);
 399
 400 struct lwp_info *find_lwp_pid (ptid_t ptid);
 401 /* For linux_stop_lwp see nat/linux-nat.h.  */
 402
 403 #ifdef HAVE_LINUX_REGSETS
 404 void initialize_regsets_info (struct regsets_info *regsets_info);
 405 #endif
 406
 407 void initialize_low_arch (void);
 408
 409 void linux_set_pc_32bit (struct regcache *regcache, CORE_ADDR pc);
 410 CORE_ADDR linux_get_pc_32bit (struct regcache *regcache);
 411
 412 void linux_set_pc_64bit (struct regcache *regcache, CORE_ADDR pc);
 413 CORE_ADDR linux_get_pc_64bit (struct regcache *regcache);
 414
 415 /* From thread-db.c  */
 416 int thread_db_init (void);
 417 void thread_db_detach (struct process_info *);
 418 void thread_db_mourn (struct process_info *);
 419 int thread_db_handle_monitor_command (char *);
 420 int thread_db_get_tls_address (struct thread_info *thread, CORE_ADDR offset,
 421                                CORE_ADDR load_module, CORE_ADDR *address);
 422 int thread_db_look_up_one_symbol (const char *name, CORE_ADDR *addrp);
 423
 424 /* Called from linux-low.c when a clone event is detected.  Upon entry,
 425    both the clone and the parent should be stopped.  This function does
 426    whatever is required have the clone under thread_db's control.  */
 427
 428 void thread_db_notice_clone (struct thread_info *parent_thr, ptid_t child_ptid);
 429
 430 bool thread_db_thread_handle (ptid_t ptid, gdb_byte **handle, int *handle_len);
 431
 432 extern int have_ptrace_getregset;