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