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