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