gdb/gdbserver/linux-low.h

   1 /* Internal interfaces for the GNU/Linux specific target code for gdbserver.
   2    Copyright (C) 2002-2014 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 "gdb_thread_db.h"
  20 #include <signal.h>
  21
  22 #include "gdbthread.h"
  23 #include "gdb_proc_service.h"
  24
  25 /* Included for ptrace type definitions.  */
  26 #include "linux-ptrace.h"
  27
  28 #define PTRACE_XFER_TYPE long
  29
  30 #ifdef HAVE_LINUX_REGSETS
  31 typedef void (*regset_fill_func) (struct regcache *, void *);
  32 typedef void (*regset_store_func) (struct regcache *, const void *);
  33 enum regset_type {
  34   GENERAL_REGS,
  35   FP_REGS,
  36   EXTENDED_REGS,
  37 };
  38
  39 struct regset_info
  40 {
  41   int get_request, set_request;
  42   /* If NT_TYPE isn't 0, it will be passed to ptrace as the 3rd
  43      argument and the 4th argument should be "const struct iovec *".  */
  44   int nt_type;
  45   int size;
  46   enum regset_type type;
  47   regset_fill_func fill_function;
  48   regset_store_func store_function;
  49 };
  50
  51 /* Aggregation of all the supported regsets of a given
  52    architecture/mode.  */
  53
  54 struct regsets_info
  55 {
  56   /* The regsets array.  */
  57   struct regset_info *regsets;
  58
  59   /* The number of regsets in the REGSETS array.  */
  60   int num_regsets;
  61
  62   /* If we get EIO on a regset, do not try it again.  Note the set of
  63      supported regsets may depend on processor mode on biarch
  64      machines.  This is a (lazily allocated) array holding one boolean
  65      byte (0/1) per regset, with each element corresponding to the
  66      regset in the REGSETS array above at the same offset.  */
  67   char *disabled_regsets;
  68 };
  69
  70 #endif
  71
  72 /* Mapping between the general-purpose registers in `struct user'
  73    format and GDB's register array layout.  */
  74
  75 struct usrregs_info
  76 {
  77   /* The number of registers accessible.  */
  78   int num_regs;
  79
  80   /* The registers map.  */
  81   int *regmap;
  82 };
  83
  84 /* All info needed to access an architecture/mode's registers.  */
  85
  86 struct regs_info
  87 {
  88   /* Regset support bitmap: 1 for registers that are transferred as a part
  89      of a regset, 0 for ones that need to be handled individually.  This
  90      can be NULL if all registers are transferred with regsets or regsets
  91      are not supported.  */
  92   unsigned char *regset_bitmap;
  93
  94   /* Info used when accessing registers with PTRACE_PEEKUSER /
  95      PTRACE_POKEUSER.  This can be NULL if all registers are
  96      transferred with regsets  .*/
  97   struct usrregs_info *usrregs;
  98
  99 #ifdef HAVE_LINUX_REGSETS
 100   /* Info used when accessing registers with regsets.  */
 101   struct regsets_info *regsets_info;
 102 #endif
 103 };
 104
 105 struct process_info_private
 106 {
 107   /* Arch-specific additions.  */
 108   struct arch_process_info *arch_private;
 109
 110   /* libthread_db-specific additions.  Not NULL if this process has loaded
 111      thread_db, and it is active.  */
 112   struct thread_db *thread_db;
 113
 114   /* &_r_debug.  0 if not yet determined.  -1 if no PT_DYNAMIC in Phdrs.  */
 115   CORE_ADDR r_debug;
 116
 117   /* This flag is true iff we've just created or attached to the first
 118      LWP of this process but it has not stopped yet.  As soon as it
 119      does, we need to call the low target's arch_setup callback.  */
 120   int new_inferior;
 121 };
 122
 123 struct lwp_info;
 124
 125 struct linux_target_ops
 126 {
 127   /* Architecture-specific setup.  */
 128   void (*arch_setup) (void);
 129
 130   const struct regs_info *(*regs_info) (void);
 131   int (*cannot_fetch_register) (int);
 132
 133   /* Returns 0 if we can store the register, 1 if we can not
 134      store the register, and 2 if failure to store the register
 135      is acceptable.  */
 136   int (*cannot_store_register) (int);
 137
 138   /* Hook to fetch a register in some non-standard way.  Used for
 139      example by backends that have read-only registers with hardcoded
 140      values (e.g., IA64's gr0/fr0/fr1).  Returns true if register
 141      REGNO was supplied, false if not, and we should fallback to the
 142      standard ptrace methods.  */
 143   int (*fetch_register) (struct regcache *regcache, int regno);
 144
 145   CORE_ADDR (*get_pc) (struct regcache *regcache);
 146   void (*set_pc) (struct regcache *regcache, CORE_ADDR newpc);
 147   const unsigned char *breakpoint;
 148   int breakpoint_len;
 149   CORE_ADDR (*breakpoint_reinsert_addr) (void);
 150
 151   int decr_pc_after_break;
 152   int (*breakpoint_at) (CORE_ADDR pc);
 153
 154   /* Breakpoint and watchpoint related functions.  See target.h for
 155      comments.  */
 156   int (*insert_point) (char type, CORE_ADDR addr, int len);
 157   int (*remove_point) (char type, CORE_ADDR addr, int len);
 158   int (*stopped_by_watchpoint) (void);
 159   CORE_ADDR (*stopped_data_address) (void);
 160
 161   /* Hooks to reformat register data for PEEKUSR/POKEUSR (in particular
 162      for registers smaller than an xfer unit).  */
 163   void (*collect_ptrace_register) (struct regcache *regcache,
 164                                    int regno, char *buf);
 165   void (*supply_ptrace_register) (struct regcache *regcache,
 166                                   int regno, const char *buf);
 167
 168   /* Hook to convert from target format to ptrace format and back.
 169      Returns true if any conversion was done; false otherwise.
 170      If DIRECTION is 1, then copy from INF to NATIVE.
 171      If DIRECTION is 0, copy from NATIVE to INF.  */
 172   int (*siginfo_fixup) (siginfo_t *native, void *inf, int direction);
 173
 174   /* Hook to call when a new process is created or attached to.
 175      If extra per-process architecture-specific data is needed,
 176      allocate it here.  */
 177   struct arch_process_info * (*new_process) (void);
 178
 179   /* Hook to call when a new thread is detected.
 180      If extra per-thread architecture-specific data is needed,
 181      allocate it here.  */
 182   struct arch_lwp_info * (*new_thread) (void);
 183
 184   /* Hook to call prior to resuming a thread.  */
 185   void (*prepare_to_resume) (struct lwp_info *);
 186
 187   /* Hook to support target specific qSupported.  */
 188   void (*process_qsupported) (const char *);
 189
 190   /* Returns true if the low target supports tracepoints.  */
 191   int (*supports_tracepoints) (void);
 192
 193   /* Fill ADDRP with the thread area address of LWPID.  Returns 0 on
 194      success, -1 on failure.  */
 195   int (*get_thread_area) (int lwpid, CORE_ADDR *addrp);
 196
 197   /* Install a fast tracepoint jump pad.  See target.h for
 198      comments.  */
 199   int (*install_fast_tracepoint_jump_pad) (CORE_ADDR tpoint, CORE_ADDR tpaddr,
 200                                            CORE_ADDR collector,
 201                                            CORE_ADDR lockaddr,
 202                                            ULONGEST orig_size,
 203                                            CORE_ADDR *jump_entry,
 204                                            CORE_ADDR *trampoline,
 205                                            ULONGEST *trampoline_size,
 206                                            unsigned char *jjump_pad_insn,
 207                                            ULONGEST *jjump_pad_insn_size,
 208                                            CORE_ADDR *adjusted_insn_addr,
 209                                            CORE_ADDR *adjusted_insn_addr_end,
 210                                            char *err);
 211
 212   /* Return the bytecode operations vector for the current inferior.
 213      Returns NULL if bytecode compilation is not supported.  */
 214   struct emit_ops *(*emit_ops) (void);
 215
 216   /* Return the minimum length of an instruction that can be safely overwritten
 217      for use as a fast tracepoint.  */
 218   int (*get_min_fast_tracepoint_insn_len) (void);
 219
 220   /* Returns true if the low target supports range stepping.  */
 221   int (*supports_range_stepping) (void);
 222 };
 223
 224 extern struct linux_target_ops the_low_target;
 225
 226 #define get_thread_lwp(thr) ((struct lwp_info *) (inferior_target_data (thr)))
 227 #define get_lwp_thread(lwp) ((lwp)->thread)
 228
 229 /* This struct is recorded in the target_data field of struct thread_info.
 230
 231    On linux ``all_threads'' is keyed by the LWP ID, which we use as the
 232    GDB protocol representation of the thread ID.  Threads also have
 233    a "process ID" (poorly named) which is (presently) the same as the
 234    LWP ID.
 235
 236    There is also ``all_processes'' is keyed by the "overall process ID",
 237    which GNU/Linux calls tgid, "thread group ID".  */
 238
 239 struct lwp_info
 240 {
 241   /* Backlink to the parent object.  */
 242   struct thread_info *thread;
 243
 244   /* If this flag is set, the next SIGSTOP will be ignored (the
 245      process will be immediately resumed).  This means that either we
 246      sent the SIGSTOP to it ourselves and got some other pending event
 247      (so the SIGSTOP is still pending), or that we stopped the
 248      inferior implicitly via PTRACE_ATTACH and have not waited for it
 249      yet.  */
 250   int stop_expected;
 251
 252   /* When this is true, we shall not try to resume this thread, even
 253      if last_resume_kind isn't resume_stop.  */
 254   int suspended;
 255
 256   /* If this flag is set, the lwp is known to be stopped right now (stop
 257      event already received in a wait()).  */
 258   int stopped;
 259
 260   /* If this flag is set, the lwp is known to be dead already (exit
 261      event already received in a wait(), and is cached in
 262      status_pending).  */
 263   int dead;
 264
 265   /* When stopped is set, the last wait status recorded for this lwp.  */
 266   int last_status;
 267
 268   /* When stopped is set, this is where the lwp stopped, with
 269      decr_pc_after_break already accounted for.  */
 270   CORE_ADDR stop_pc;
 271
 272   /* If this flag is set, STATUS_PENDING is a waitstatus that has not yet
 273      been reported.  */
 274   int status_pending_p;
 275   int status_pending;
 276
 277   /* STOPPED_BY_WATCHPOINT is non-zero if this LWP stopped with a data
 278      watchpoint trap.  */
 279   int stopped_by_watchpoint;
 280
 281   /* On architectures where it is possible to know the data address of
 282      a triggered watchpoint, STOPPED_DATA_ADDRESS is non-zero, and
 283      contains such data address.  Only valid if STOPPED_BY_WATCHPOINT
 284      is true.  */
 285   CORE_ADDR stopped_data_address;
 286
 287   /* If this is non-zero, it is a breakpoint to be reinserted at our next
 288      stop (SIGTRAP stops only).  */
 289   CORE_ADDR bp_reinsert;
 290
 291   /* If this flag is set, the last continue operation at the ptrace
 292      level on this process was a single-step.  */
 293   int stepping;
 294
 295   /* Range to single step within.  This is a copy of the step range
 296      passed along the last resume request.  See 'struct
 297      thread_resume'.  */
 298   CORE_ADDR step_range_start;   /* Inclusive */
 299   CORE_ADDR step_range_end;     /* Exclusive */
 300
 301   /* If this flag is set, we need to set the event request flags the
 302      next time we see this LWP stop.  */
 303   int must_set_ptrace_flags;
 304
 305   /* If this is non-zero, it points to a chain of signals which need to
 306      be delivered to this process.  */
 307   struct pending_signals *pending_signals;
 308
 309   /* A link used when resuming.  It is initialized from the resume request,
 310      and then processed and cleared in linux_resume_one_lwp.  */
 311   struct thread_resume *resume;
 312
 313   /* True if it is known that this lwp is presently collecting a fast
 314      tracepoint (it is in the jump pad or in some code that will
 315      return to the jump pad.  Normally, we won't care about this, but
 316      we will if a signal arrives to this lwp while it is
 317      collecting.  */
 318   int collecting_fast_tracepoint;
 319
 320   /* If this is non-zero, it points to a chain of signals which need
 321      to be reported to GDB.  These were deferred because the thread
 322      was doing a fast tracepoint collect when they arrived.  */
 323   struct pending_signals *pending_signals_to_report;
 324
 325   /* When collecting_fast_tracepoint is first found to be 1, we insert
 326      a exit-jump-pad-quickly breakpoint.  This is it.  */
 327   struct breakpoint *exit_jump_pad_bkpt;
 328
 329   /* True if the LWP was seen stop at an internal breakpoint and needs
 330      stepping over later when it is resumed.  */
 331   int need_step_over;
 332
 333 #ifdef USE_THREAD_DB
 334   int thread_known;
 335   /* The thread handle, used for e.g. TLS access.  Only valid if
 336      THREAD_KNOWN is set.  */
 337   td_thrhandle_t th;
 338 #endif
 339
 340   /* Arch-specific additions.  */
 341   struct arch_lwp_info *arch_private;
 342 };
 343
 344 int linux_pid_exe_is_elf_64_file (int pid, unsigned int *machine);
 345
 346 /* Attach to PTID.  Returns 0 on success, non-zero otherwise (an
 347    errno).  */
 348 int linux_attach_lwp (ptid_t ptid);
 349
 350 /* Return the reason an attach failed, in string form.  ERR is the
 351    error returned by linux_attach_lwp (an errno).  This string should
 352    be copied into a buffer by the client if the string will not be
 353    immediately used, or if it must persist.  */
 354 char *linux_attach_fail_reason_string (ptid_t ptid, int err);
 355
 356 struct lwp_info *find_lwp_pid (ptid_t ptid);
 357 void linux_stop_lwp (struct lwp_info *lwp);
 358
 359 #ifdef HAVE_LINUX_REGSETS
 360 void initialize_regsets_info (struct regsets_info *regsets_info);
 361 #endif
 362
 363 void initialize_low_arch (void);
 364
 365 /* From thread-db.c  */
 366 int thread_db_init (int use_events);
 367 void thread_db_detach (struct process_info *);
 368 void thread_db_mourn (struct process_info *);
 369 int thread_db_handle_monitor_command (char *);
 370 int thread_db_get_tls_address (struct thread_info *thread, CORE_ADDR offset,
 371                                CORE_ADDR load_module, CORE_ADDR *address);
 372 int thread_db_look_up_one_symbol (const char *name, CORE_ADDR *addrp);