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
 120 struct lwp_info;
 121
 122 struct linux_target_ops
 123 {
 124   /* Architecture-specific setup.  */
 125   void (*arch_setup) (void);
 126
 127   const struct regs_info *(*regs_info) (void);
 128   int (*cannot_fetch_register) (int);
 129
 130   /* Returns 0 if we can store the register, 1 if we can not
 131      store the register, and 2 if failure to store the register
 132      is acceptable.  */
 133   int (*cannot_store_register) (int);
 134
 135   /* Hook to fetch a register in some non-standard way.  Used for
 136      example by backends that have read-only registers with hardcoded
 137      values (e.g., IA64's gr0/fr0/fr1).  Returns true if register
 138      REGNO was supplied, false if not, and we should fallback to the
 139      standard ptrace methods.  */
 140   int (*fetch_register) (struct regcache *regcache, int regno);
 141
 142   CORE_ADDR (*get_pc) (struct regcache *regcache);
 143   void (*set_pc) (struct regcache *regcache, CORE_ADDR newpc);
 144   const unsigned char *breakpoint;
 145   int breakpoint_len;
 146   CORE_ADDR (*breakpoint_reinsert_addr) (void);
 147
 148   int decr_pc_after_break;
 149   int (*breakpoint_at) (CORE_ADDR pc);
 150
 151   /* Breakpoint and watchpoint related functions.  See target.h for
 152      comments.  */
 153   int (*supports_z_point_type) (char z_type);
 154   int (*insert_point) (enum raw_bkpt_type type, CORE_ADDR addr,
 155                        int size, struct raw_breakpoint *bp);
 156   int (*remove_point) (enum raw_bkpt_type type, CORE_ADDR addr,
 157                        int size, struct raw_breakpoint *bp);
 158
 159   int (*stopped_by_watchpoint) (void);
 160   CORE_ADDR (*stopped_data_address) (void);
 161
 162   /* Hooks to reformat register data for PEEKUSR/POKEUSR (in particular
 163      for registers smaller than an xfer unit).  */
 164   void (*collect_ptrace_register) (struct regcache *regcache,
 165                                    int regno, char *buf);
 166   void (*supply_ptrace_register) (struct regcache *regcache,
 167                                   int regno, const char *buf);
 168
 169   /* Hook to convert from target format to ptrace format and back.
 170      Returns true if any conversion was done; false otherwise.
 171      If DIRECTION is 1, then copy from INF to NATIVE.
 172      If DIRECTION is 0, copy from NATIVE to INF.  */
 173   int (*siginfo_fixup) (siginfo_t *native, void *inf, int direction);
 174
 175   /* Hook to call when a new process is created or attached to.
 176      If extra per-process architecture-specific data is needed,
 177      allocate it here.  */
 178   struct arch_process_info * (*new_process) (void);
 179
 180   /* Hook to call when a new thread is detected.
 181      If extra per-thread architecture-specific data is needed,
 182      allocate it here.  */
 183   void (*new_thread) (struct lwp_info *);
 184
 185   /* Hook to call, if any, when a new fork is attached.  */
 186   void (*new_fork) (struct process_info *parent, struct process_info *child);
 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 /* This struct is recorded in the target_data field of struct thread_info.
 234
 235    On linux ``all_threads'' is keyed by the LWP ID, which we use as the
 236    GDB protocol representation of the thread ID.  Threads also have
 237    a "process ID" (poorly named) which is (presently) the same as the
 238    LWP ID.
 239
 240    There is also ``all_processes'' is keyed by the "overall process ID",
 241    which GNU/Linux calls tgid, "thread group ID".  */
 242
 243 struct lwp_info
 244 {
 245   /* Backlink to the parent object.  */
 246   struct thread_info *thread;
 247
 248   /* If this flag is set, the next SIGSTOP will be ignored (the
 249      process will be immediately resumed).  This means that either we
 250      sent the SIGSTOP to it ourselves and got some other pending event
 251      (so the SIGSTOP is still pending), or that we stopped the
 252      inferior implicitly via PTRACE_ATTACH and have not waited for it
 253      yet.  */
 254   int stop_expected;
 255
 256   /* When this is true, we shall not try to resume this thread, even
 257      if last_resume_kind isn't resume_stop.  */
 258   int suspended;
 259
 260   /* If this flag is set, the lwp is known to be stopped right now (stop
 261      event already received in a wait()).  */
 262   int stopped;
 263
 264   /* When stopped is set, the last wait status recorded for this lwp.  */
 265   int last_status;
 266
 267   /* If WAITSTATUS->KIND != TARGET_WAITKIND_IGNORE, the waitstatus for
 268      this LWP's last event, to pass to GDB without any further
 269      processing.  This is used to store extended ptrace event
 270      information or exit status until it can be reported to GDB.  */
 271   struct target_waitstatus waitstatus;
 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 /* For linux_stop_lwp see nat/linux-nat.h.  */
 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);
 373
 374 extern int have_ptrace_getregset;