gdb/gdbserver/linux-low.h

   1 /* Internal interfaces for the GNU/Linux specific target code for gdbserver.
   2    Copyright (C) 2002-2016 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 /* The arch's regsets array initializer must be terminated with a NULL
  42    regset.  */
  43 #define NULL_REGSET \
  44   { 0, 0, 0, -1, (enum regset_type) -1, NULL, NULL }
  45
  46 struct regset_info
  47 {
  48   int get_request, set_request;
  49   /* If NT_TYPE isn't 0, it will be passed to ptrace as the 3rd
  50      argument and the 4th argument should be "const struct iovec *".  */
  51   int nt_type;
  52   int size;
  53   enum regset_type type;
  54   regset_fill_func fill_function;
  55   regset_store_func store_function;
  56 };
  57
  58 /* Aggregation of all the supported regsets of a given
  59    architecture/mode.  */
  60
  61 struct regsets_info
  62 {
  63   /* The regsets array.  */
  64   struct regset_info *regsets;
  65
  66   /* The number of regsets in the REGSETS array.  */
  67   int num_regsets;
  68
  69   /* If we get EIO on a regset, do not try it again.  Note the set of
  70      supported regsets may depend on processor mode on biarch
  71      machines.  This is a (lazily allocated) array holding one boolean
  72      byte (0/1) per regset, with each element corresponding to the
  73      regset in the REGSETS array above at the same offset.  */
  74   char *disabled_regsets;
  75 };
  76
  77 #endif
  78
  79 /* Mapping between the general-purpose registers in `struct user'
  80    format and GDB's register array layout.  */
  81
  82 struct usrregs_info
  83 {
  84   /* The number of registers accessible.  */
  85   int num_regs;
  86
  87   /* The registers map.  */
  88   int *regmap;
  89 };
  90
  91 /* All info needed to access an architecture/mode's registers.  */
  92
  93 struct regs_info
  94 {
  95   /* Regset support bitmap: 1 for registers that are transferred as a part
  96      of a regset, 0 for ones that need to be handled individually.  This
  97      can be NULL if all registers are transferred with regsets or regsets
  98      are not supported.  */
  99   unsigned char *regset_bitmap;
 100
 101   /* Info used when accessing registers with PTRACE_PEEKUSER /
 102      PTRACE_POKEUSER.  This can be NULL if all registers are
 103      transferred with regsets  .*/
 104   struct usrregs_info *usrregs;
 105
 106 #ifdef HAVE_LINUX_REGSETS
 107   /* Info used when accessing registers with regsets.  */
 108   struct regsets_info *regsets_info;
 109 #endif
 110 };
 111
 112 struct process_info_private
 113 {
 114   /* Arch-specific additions.  */
 115   struct arch_process_info *arch_private;
 116
 117   /* libthread_db-specific additions.  Not NULL if this process has loaded
 118      thread_db, and it is active.  */
 119   struct thread_db *thread_db;
 120
 121   /* &_r_debug.  0 if not yet determined.  -1 if no PT_DYNAMIC in Phdrs.  */
 122   CORE_ADDR r_debug;
 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
 150   /* See target.h for details.  */
 151   int (*breakpoint_kind_from_pc) (CORE_ADDR *pcptr);
 152
 153   /* See target.h for details.  */
 154   const gdb_byte *(*sw_breakpoint_from_kind) (int kind, int *size);
 155
 156   /* Find the next possible PCs after the current instruction executes.  */
 157   VEC (CORE_ADDR) *(*get_next_pcs) (CORE_ADDR pc, struct regcache *regcache);
 158
 159   int decr_pc_after_break;
 160   int (*breakpoint_at) (CORE_ADDR pc);
 161
 162   /* Breakpoint and watchpoint related functions.  See target.h for
 163      comments.  */
 164   int (*supports_z_point_type) (char z_type);
 165   int (*insert_point) (enum raw_bkpt_type type, CORE_ADDR addr,
 166                        int size, struct raw_breakpoint *bp);
 167   int (*remove_point) (enum raw_bkpt_type type, CORE_ADDR addr,
 168                        int size, struct raw_breakpoint *bp);
 169
 170   int (*stopped_by_watchpoint) (void);
 171   CORE_ADDR (*stopped_data_address) (void);
 172
 173   /* Hooks to reformat register data for PEEKUSR/POKEUSR (in particular
 174      for registers smaller than an xfer unit).  */
 175   void (*collect_ptrace_register) (struct regcache *regcache,
 176                                    int regno, char *buf);
 177   void (*supply_ptrace_register) (struct regcache *regcache,
 178                                   int regno, const char *buf);
 179
 180   /* Hook to convert from target format to ptrace format and back.
 181      Returns true if any conversion was done; false otherwise.
 182      If DIRECTION is 1, then copy from INF to NATIVE.
 183      If DIRECTION is 0, copy from NATIVE to INF.  */
 184   int (*siginfo_fixup) (siginfo_t *native, void *inf, int direction);
 185
 186   /* Hook to call when a new process is created or attached to.
 187      If extra per-process architecture-specific data is needed,
 188      allocate it here.  */
 189   struct arch_process_info * (*new_process) (void);
 190
 191   /* Hook to call when a new thread is detected.
 192      If extra per-thread architecture-specific data is needed,
 193      allocate it here.  */
 194   void (*new_thread) (struct lwp_info *);
 195
 196   /* Hook to call, if any, when a new fork is attached.  */
 197   void (*new_fork) (struct process_info *parent, struct process_info *child);
 198
 199   /* Hook to call prior to resuming a thread.  */
 200   void (*prepare_to_resume) (struct lwp_info *);
 201
 202   /* Hook to support target specific qSupported.  */
 203   void (*process_qsupported) (char **, int count);
 204
 205   /* Returns true if the low target supports tracepoints.  */
 206   int (*supports_tracepoints) (void);
 207
 208   /* Fill ADDRP with the thread area address of LWPID.  Returns 0 on
 209      success, -1 on failure.  */
 210   int (*get_thread_area) (int lwpid, CORE_ADDR *addrp);
 211
 212   /* Install a fast tracepoint jump pad.  See target.h for
 213      comments.  */
 214   int (*install_fast_tracepoint_jump_pad) (CORE_ADDR tpoint, CORE_ADDR tpaddr,
 215                                            CORE_ADDR collector,
 216                                            CORE_ADDR lockaddr,
 217                                            ULONGEST orig_size,
 218                                            CORE_ADDR *jump_entry,
 219                                            CORE_ADDR *trampoline,
 220                                            ULONGEST *trampoline_size,
 221                                            unsigned char *jjump_pad_insn,
 222                                            ULONGEST *jjump_pad_insn_size,
 223                                            CORE_ADDR *adjusted_insn_addr,
 224                                            CORE_ADDR *adjusted_insn_addr_end,
 225                                            char *err);
 226
 227   /* Return the bytecode operations vector for the current inferior.
 228      Returns NULL if bytecode compilation is not supported.  */
 229   struct emit_ops *(*emit_ops) (void);
 230
 231   /* Return the minimum length of an instruction that can be safely overwritten
 232      for use as a fast tracepoint.  */
 233   int (*get_min_fast_tracepoint_insn_len) (void);
 234
 235   /* Returns true if the low target supports range stepping.  */
 236   int (*supports_range_stepping) (void);
 237
 238   /* See target.h.  */
 239   int (*breakpoint_kind_from_current_state) (CORE_ADDR *pcptr);
 240
 241   /* See target.h.  */
 242   int (*supports_hardware_single_step) (void);
 243 };
 244
 245 extern struct linux_target_ops the_low_target;
 246
 247 #define get_thread_lwp(thr) ((struct lwp_info *) (inferior_target_data (thr)))
 248 #define get_lwp_thread(lwp) ((lwp)->thread)
 249
 250 /* This struct is recorded in the target_data field of struct thread_info.
 251
 252    On linux ``all_threads'' is keyed by the LWP ID, which we use as the
 253    GDB protocol representation of the thread ID.  Threads also have
 254    a "process ID" (poorly named) which is (presently) the same as the
 255    LWP ID.
 256
 257    There is also ``all_processes'' is keyed by the "overall process ID",
 258    which GNU/Linux calls tgid, "thread group ID".  */
 259
 260 struct lwp_info
 261 {
 262   /* Backlink to the parent object.  */
 263   struct thread_info *thread;
 264
 265   /* If this flag is set, the next SIGSTOP will be ignored (the
 266      process will be immediately resumed).  This means that either we
 267      sent the SIGSTOP to it ourselves and got some other pending event
 268      (so the SIGSTOP is still pending), or that we stopped the
 269      inferior implicitly via PTRACE_ATTACH and have not waited for it
 270      yet.  */
 271   int stop_expected;
 272
 273   /* When this is true, we shall not try to resume this thread, even
 274      if last_resume_kind isn't resume_stop.  */
 275   int suspended;
 276
 277   /* If this flag is set, the lwp is known to be stopped right now (stop
 278      event already received in a wait()).  */
 279   int stopped;
 280
 281   /* When stopped is set, the last wait status recorded for this lwp.  */
 282   int last_status;
 283
 284   /* If WAITSTATUS->KIND != TARGET_WAITKIND_IGNORE, the waitstatus for
 285      this LWP's last event, to pass to GDB without any further
 286      processing.  This is used to store extended ptrace event
 287      information or exit status until it can be reported to GDB.  */
 288   struct target_waitstatus waitstatus;
 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 target_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 /* For linux_stop_lwp see nat/linux-nat.h.  */
 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 (void);
 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);
 390
 391 extern int have_ptrace_getregset;