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
 238 extern struct linux_target_ops the_low_target;
 239
 240 #define get_thread_lwp(thr) ((struct lwp_info *) (inferior_target_data (thr)))
 241 #define get_lwp_thread(lwp) ((lwp)->thread)
 242
 243 /* This struct is recorded in the target_data field of struct thread_info.
 244
 245    On linux ``all_threads'' is keyed by the LWP ID, which we use as the
 246    GDB protocol representation of the thread ID.  Threads also have
 247    a "process ID" (poorly named) which is (presently) the same as the
 248    LWP ID.
 249
 250    There is also ``all_processes'' is keyed by the "overall process ID",
 251    which GNU/Linux calls tgid, "thread group ID".  */
 252
 253 struct lwp_info
 254 {
 255   /* Backlink to the parent object.  */
 256   struct thread_info *thread;
 257
 258   /* If this flag is set, the next SIGSTOP will be ignored (the
 259      process will be immediately resumed).  This means that either we
 260      sent the SIGSTOP to it ourselves and got some other pending event
 261      (so the SIGSTOP is still pending), or that we stopped the
 262      inferior implicitly via PTRACE_ATTACH and have not waited for it
 263      yet.  */
 264   int stop_expected;
 265
 266   /* When this is true, we shall not try to resume this thread, even
 267      if last_resume_kind isn't resume_stop.  */
 268   int suspended;
 269
 270   /* If this flag is set, the lwp is known to be stopped right now (stop
 271      event already received in a wait()).  */
 272   int stopped;
 273
 274   /* When stopped is set, the last wait status recorded for this lwp.  */
 275   int last_status;
 276
 277   /* If WAITSTATUS->KIND != TARGET_WAITKIND_IGNORE, the waitstatus for
 278      this LWP's last event, to pass to GDB without any further
 279      processing.  This is used to store extended ptrace event
 280      information or exit status until it can be reported to GDB.  */
 281   struct target_waitstatus waitstatus;
 282
 283   /* When stopped is set, this is where the lwp last stopped, with
 284      decr_pc_after_break already accounted for.  If the LWP is
 285      running, this is the address at which the lwp was resumed.  */
 286   CORE_ADDR stop_pc;
 287
 288   /* If this flag is set, STATUS_PENDING is a waitstatus that has not yet
 289      been reported.  */
 290   int status_pending_p;
 291   int status_pending;
 292
 293   /* The reason the LWP last stopped, if we need to track it
 294      (breakpoint, watchpoint, etc.)  */
 295   enum target_stop_reason stop_reason;
 296
 297   /* On architectures where it is possible to know the data address of
 298      a triggered watchpoint, STOPPED_DATA_ADDRESS is non-zero, and
 299      contains such data address.  Only valid if STOPPED_BY_WATCHPOINT
 300      is true.  */
 301   CORE_ADDR stopped_data_address;
 302
 303   /* If this is non-zero, it is a breakpoint to be reinserted at our next
 304      stop (SIGTRAP stops only).  */
 305   CORE_ADDR bp_reinsert;
 306
 307   /* If this flag is set, the last continue operation at the ptrace
 308      level on this process was a single-step.  */
 309   int stepping;
 310
 311   /* Range to single step within.  This is a copy of the step range
 312      passed along the last resume request.  See 'struct
 313      thread_resume'.  */
 314   CORE_ADDR step_range_start;   /* Inclusive */
 315   CORE_ADDR step_range_end;     /* Exclusive */
 316
 317   /* If this flag is set, we need to set the event request flags the
 318      next time we see this LWP stop.  */
 319   int must_set_ptrace_flags;
 320
 321   /* If this is non-zero, it points to a chain of signals which need to
 322      be delivered to this process.  */
 323   struct pending_signals *pending_signals;
 324
 325   /* A link used when resuming.  It is initialized from the resume request,
 326      and then processed and cleared in linux_resume_one_lwp.  */
 327   struct thread_resume *resume;
 328
 329   /* True if it is known that this lwp is presently collecting a fast
 330      tracepoint (it is in the jump pad or in some code that will
 331      return to the jump pad.  Normally, we won't care about this, but
 332      we will if a signal arrives to this lwp while it is
 333      collecting.  */
 334   int collecting_fast_tracepoint;
 335
 336   /* If this is non-zero, it points to a chain of signals which need
 337      to be reported to GDB.  These were deferred because the thread
 338      was doing a fast tracepoint collect when they arrived.  */
 339   struct pending_signals *pending_signals_to_report;
 340
 341   /* When collecting_fast_tracepoint is first found to be 1, we insert
 342      a exit-jump-pad-quickly breakpoint.  This is it.  */
 343   struct breakpoint *exit_jump_pad_bkpt;
 344
 345   /* True if the LWP was seen stop at an internal breakpoint and needs
 346      stepping over later when it is resumed.  */
 347   int need_step_over;
 348
 349 #ifdef USE_THREAD_DB
 350   int thread_known;
 351   /* The thread handle, used for e.g. TLS access.  Only valid if
 352      THREAD_KNOWN is set.  */
 353   td_thrhandle_t th;
 354 #endif
 355
 356   /* Arch-specific additions.  */
 357   struct arch_lwp_info *arch_private;
 358 };
 359
 360 int linux_pid_exe_is_elf_64_file (int pid, unsigned int *machine);
 361
 362 /* Attach to PTID.  Returns 0 on success, non-zero otherwise (an
 363    errno).  */
 364 int linux_attach_lwp (ptid_t ptid);
 365
 366 struct lwp_info *find_lwp_pid (ptid_t ptid);
 367 /* For linux_stop_lwp see nat/linux-nat.h.  */
 368
 369 #ifdef HAVE_LINUX_REGSETS
 370 void initialize_regsets_info (struct regsets_info *regsets_info);
 371 #endif
 372
 373 void initialize_low_arch (void);
 374
 375 /* From thread-db.c  */
 376 int thread_db_init (int use_events);
 377 void thread_db_detach (struct process_info *);
 378 void thread_db_mourn (struct process_info *);
 379 int thread_db_handle_monitor_command (char *);
 380 int thread_db_get_tls_address (struct thread_info *thread, CORE_ADDR offset,
 381                                CORE_ADDR load_module, CORE_ADDR *address);
 382 int thread_db_look_up_one_symbol (const char *name, CORE_ADDR *addrp);
 383
 384 extern int have_ptrace_getregset;