gdb/gdbserver/linux-low.h

   1 /* Internal interfaces for the GNU/Linux specific target code for gdbserver.
   2    Copyright (C) 2002-2015 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/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 "nat/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 (*supports_z_point_type) (char z_type);
 157   int (*insert_point) (enum raw_bkpt_type type, CORE_ADDR addr,
 158                        int size, struct raw_breakpoint *bp);
 159   int (*remove_point) (enum raw_bkpt_type type, CORE_ADDR addr,
 160                        int size, struct raw_breakpoint *bp);
 161
 162   int (*stopped_by_watchpoint) (void);
 163   CORE_ADDR (*stopped_data_address) (void);
 164
 165   /* Hooks to reformat register data for PEEKUSR/POKEUSR (in particular
 166      for registers smaller than an xfer unit).  */
 167   void (*collect_ptrace_register) (struct regcache *regcache,
 168                                    int regno, char *buf);
 169   void (*supply_ptrace_register) (struct regcache *regcache,
 170                                   int regno, const char *buf);
 171
 172   /* Hook to convert from target format to ptrace format and back.
 173      Returns true if any conversion was done; false otherwise.
 174      If DIRECTION is 1, then copy from INF to NATIVE.
 175      If DIRECTION is 0, copy from NATIVE to INF.  */
 176   int (*siginfo_fixup) (siginfo_t *native, void *inf, int direction);
 177
 178   /* Hook to call when a new process is created or attached to.
 179      If extra per-process architecture-specific data is needed,
 180      allocate it here.  */
 181   struct arch_process_info * (*new_process) (void);
 182
 183   /* Hook to call when a new thread is detected.
 184      If extra per-thread architecture-specific data is needed,
 185      allocate it here.  */
 186   struct arch_lwp_info * (*new_thread) (void);
 187
 188   /* Hook to call prior to resuming a thread.  */
 189   void (*prepare_to_resume) (struct lwp_info *);
 190
 191   /* Hook to support target specific qSupported.  */
 192   void (*process_qsupported) (const char *);
 193
 194   /* Returns true if the low target supports tracepoints.  */
 195   int (*supports_tracepoints) (void);
 196
 197   /* Fill ADDRP with the thread area address of LWPID.  Returns 0 on
 198      success, -1 on failure.  */
 199   int (*get_thread_area) (int lwpid, CORE_ADDR *addrp);
 200
 201   /* Install a fast tracepoint jump pad.  See target.h for
 202      comments.  */
 203   int (*install_fast_tracepoint_jump_pad) (CORE_ADDR tpoint, CORE_ADDR tpaddr,
 204                                            CORE_ADDR collector,
 205                                            CORE_ADDR lockaddr,
 206                                            ULONGEST orig_size,
 207                                            CORE_ADDR *jump_entry,
 208                                            CORE_ADDR *trampoline,
 209                                            ULONGEST *trampoline_size,
 210                                            unsigned char *jjump_pad_insn,
 211                                            ULONGEST *jjump_pad_insn_size,
 212                                            CORE_ADDR *adjusted_insn_addr,
 213                                            CORE_ADDR *adjusted_insn_addr_end,
 214                                            char *err);
 215
 216   /* Return the bytecode operations vector for the current inferior.
 217      Returns NULL if bytecode compilation is not supported.  */
 218   struct emit_ops *(*emit_ops) (void);
 219
 220   /* Return the minimum length of an instruction that can be safely overwritten
 221      for use as a fast tracepoint.  */
 222   int (*get_min_fast_tracepoint_insn_len) (void);
 223
 224   /* Returns true if the low target supports range stepping.  */
 225   int (*supports_range_stepping) (void);
 226 };
 227
 228 extern struct linux_target_ops the_low_target;
 229
 230 #define get_thread_lwp(thr) ((struct lwp_info *) (inferior_target_data (thr)))
 231 #define get_lwp_thread(lwp) ((lwp)->thread)
 232
 233 /* Reasons an LWP last stopped.  */
 234
 235 enum lwp_stop_reason
 236 {
 237   /* Either not stopped, or stopped for a reason that doesn't require
 238      special tracking.  */
 239   LWP_STOPPED_BY_NO_REASON,
 240
 241   /* Stopped by a software breakpoint.  */
 242   LWP_STOPPED_BY_SW_BREAKPOINT,
 243
 244   /* Stopped by a hardware breakpoint.  */
 245   LWP_STOPPED_BY_HW_BREAKPOINT,
 246
 247   /* Stopped by a watchpoint.  */
 248   LWP_STOPPED_BY_WATCHPOINT
 249 };
 250
 251 /* This struct is recorded in the target_data field of struct thread_info.
 252
 253    On linux ``all_threads'' is keyed by the LWP ID, which we use as the
 254    GDB protocol representation of the thread ID.  Threads also have
 255    a "process ID" (poorly named) which is (presently) the same as the
 256    LWP ID.
 257
 258    There is also ``all_processes'' is keyed by the "overall process ID",
 259    which GNU/Linux calls tgid, "thread group ID".  */
 260
 261 struct lwp_info
 262 {
 263   /* Backlink to the parent object.  */
 264   struct thread_info *thread;
 265
 266   /* If this flag is set, the next SIGSTOP will be ignored (the
 267      process will be immediately resumed).  This means that either we
 268      sent the SIGSTOP to it ourselves and got some other pending event
 269      (so the SIGSTOP is still pending), or that we stopped the
 270      inferior implicitly via PTRACE_ATTACH and have not waited for it
 271      yet.  */
 272   int stop_expected;
 273
 274   /* When this is true, we shall not try to resume this thread, even
 275      if last_resume_kind isn't resume_stop.  */
 276   int suspended;
 277
 278   /* If this flag is set, the lwp is known to be stopped right now (stop
 279      event already received in a wait()).  */
 280   int stopped;
 281
 282   /* If this flag is set, the lwp is known to be dead already (exit
 283      event already received in a wait(), and is cached in
 284      status_pending).  */
 285   int dead;
 286
 287   /* When stopped is set, the last wait status recorded for this lwp.  */
 288   int last_status;
 289
 290   /* When stopped is set, this is where the lwp last stopped, with
 291      decr_pc_after_break already accounted for.  If the LWP is
 292      running, this is the address at which the lwp was resumed.  */
 293   CORE_ADDR stop_pc;
 294
 295   /* If this flag is set, STATUS_PENDING is a waitstatus that has not yet
 296      been reported.  */
 297   int status_pending_p;
 298   int status_pending;
 299
 300   /* The reason the LWP last stopped, if we need to track it
 301      (breakpoint, watchpoint, etc.)  */
 302   enum lwp_stop_reason stop_reason;
 303
 304   /* On architectures where it is possible to know the data address of
 305      a triggered watchpoint, STOPPED_DATA_ADDRESS is non-zero, and
 306      contains such data address.  Only valid if STOPPED_BY_WATCHPOINT
 307      is true.  */
 308   CORE_ADDR stopped_data_address;
 309
 310   /* If this is non-zero, it is a breakpoint to be reinserted at our next
 311      stop (SIGTRAP stops only).  */
 312   CORE_ADDR bp_reinsert;
 313
 314   /* If this flag is set, the last continue operation at the ptrace
 315      level on this process was a single-step.  */
 316   int stepping;
 317
 318   /* Range to single step within.  This is a copy of the step range
 319      passed along the last resume request.  See 'struct
 320      thread_resume'.  */
 321   CORE_ADDR step_range_start;   /* Inclusive */
 322   CORE_ADDR step_range_end;     /* Exclusive */
 323
 324   /* If this flag is set, we need to set the event request flags the
 325      next time we see this LWP stop.  */
 326   int must_set_ptrace_flags;
 327
 328   /* If this is non-zero, it points to a chain of signals which need to
 329      be delivered to this process.  */
 330   struct pending_signals *pending_signals;
 331
 332   /* A link used when resuming.  It is initialized from the resume request,
 333      and then processed and cleared in linux_resume_one_lwp.  */
 334   struct thread_resume *resume;
 335
 336   /* True if it is known that this lwp is presently collecting a fast
 337      tracepoint (it is in the jump pad or in some code that will
 338      return to the jump pad.  Normally, we won't care about this, but
 339      we will if a signal arrives to this lwp while it is
 340      collecting.  */
 341   int collecting_fast_tracepoint;
 342
 343   /* If this is non-zero, it points to a chain of signals which need
 344      to be reported to GDB.  These were deferred because the thread
 345      was doing a fast tracepoint collect when they arrived.  */
 346   struct pending_signals *pending_signals_to_report;
 347
 348   /* When collecting_fast_tracepoint is first found to be 1, we insert
 349      a exit-jump-pad-quickly breakpoint.  This is it.  */
 350   struct breakpoint *exit_jump_pad_bkpt;
 351
 352   /* True if the LWP was seen stop at an internal breakpoint and needs
 353      stepping over later when it is resumed.  */
 354   int need_step_over;
 355
 356 #ifdef USE_THREAD_DB
 357   int thread_known;
 358   /* The thread handle, used for e.g. TLS access.  Only valid if
 359      THREAD_KNOWN is set.  */
 360   td_thrhandle_t th;
 361 #endif
 362
 363   /* Arch-specific additions.  */
 364   struct arch_lwp_info *arch_private;
 365 };
 366
 367 int linux_pid_exe_is_elf_64_file (int pid, unsigned int *machine);
 368
 369 /* Attach to PTID.  Returns 0 on success, non-zero otherwise (an
 370    errno).  */
 371 int linux_attach_lwp (ptid_t ptid);
 372
 373 struct lwp_info *find_lwp_pid (ptid_t ptid);
 374 void linux_stop_lwp (struct lwp_info *lwp);
 375
 376 #ifdef HAVE_LINUX_REGSETS
 377 void initialize_regsets_info (struct regsets_info *regsets_info);
 378 #endif
 379
 380 void initialize_low_arch (void);
 381
 382 /* From thread-db.c  */
 383 int thread_db_init (int use_events);
 384 void thread_db_detach (struct process_info *);
 385 void thread_db_mourn (struct process_info *);
 386 int thread_db_handle_monitor_command (char *);
 387 int thread_db_get_tls_address (struct thread_info *thread, CORE_ADDR offset,
 388                                CORE_ADDR load_module, CORE_ADDR *address);
 389 int thread_db_look_up_one_symbol (const char *name, CORE_ADDR *addrp);