gdb/gdbserver/linux-low.h

   1 /* Internal interfaces for the GNU/Linux specific target code for gdbserver.
   2    Copyright (C) 2002-2017 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 #include "tracepoint.h"
  30
  31 #define PTRACE_XFER_TYPE long
  32
  33 #ifdef HAVE_LINUX_REGSETS
  34 typedef void (*regset_fill_func) (struct regcache *, void *);
  35 typedef void (*regset_store_func) (struct regcache *, const void *);
  36 enum regset_type {
  37   GENERAL_REGS,
  38   FP_REGS,
  39   EXTENDED_REGS,
  40 };
  41
  42 /* The arch's regsets array initializer must be terminated with a NULL
  43    regset.  */
  44 #define NULL_REGSET \
  45   { 0, 0, 0, -1, (enum regset_type) -1, NULL, NULL }
  46
  47 struct regset_info
  48 {
  49   int get_request, set_request;
  50   /* If NT_TYPE isn't 0, it will be passed to ptrace as the 3rd
  51      argument and the 4th argument should be "const struct iovec *".  */
  52   int nt_type;
  53   int size;
  54   enum regset_type type;
  55   regset_fill_func fill_function;
  56   regset_store_func store_function;
  57 };
  58
  59 /* Aggregation of all the supported regsets of a given
  60    architecture/mode.  */
  61
  62 struct regsets_info
  63 {
  64   /* The regsets array.  */
  65   struct regset_info *regsets;
  66
  67   /* The number of regsets in the REGSETS array.  */
  68   int num_regsets;
  69
  70   /* If we get EIO on a regset, do not try it again.  Note the set of
  71      supported regsets may depend on processor mode on biarch
  72      machines.  This is a (lazily allocated) array holding one boolean
  73      byte (0/1) per regset, with each element corresponding to the
  74      regset in the REGSETS array above at the same offset.  */
  75   char *disabled_regsets;
  76 };
  77
  78 #endif
  79
  80 /* Mapping between the general-purpose registers in `struct user'
  81    format and GDB's register array layout.  */
  82
  83 struct usrregs_info
  84 {
  85   /* The number of registers accessible.  */
  86   int num_regs;
  87
  88   /* The registers map.  */
  89   int *regmap;
  90 };
  91
  92 /* All info needed to access an architecture/mode's registers.  */
  93
  94 struct regs_info
  95 {
  96   /* Regset support bitmap: 1 for registers that are transferred as a part
  97      of a regset, 0 for ones that need to be handled individually.  This
  98      can be NULL if all registers are transferred with regsets or regsets
  99      are not supported.  */
 100   unsigned char *regset_bitmap;
 101
 102   /* Info used when accessing registers with PTRACE_PEEKUSER /
 103      PTRACE_POKEUSER.  This can be NULL if all registers are
 104      transferred with regsets  .*/
 105   struct usrregs_info *usrregs;
 106
 107 #ifdef HAVE_LINUX_REGSETS
 108   /* Info used when accessing registers with regsets.  */
 109   struct regsets_info *regsets_info;
 110 #endif
 111 };
 112
 113 struct process_info_private
 114 {
 115   /* Arch-specific additions.  */
 116   struct arch_process_info *arch_private;
 117
 118   /* libthread_db-specific additions.  Not NULL if this process has loaded
 119      thread_db, and it is active.  */
 120   struct thread_db *thread_db;
 121
 122   /* &_r_debug.  0 if not yet determined.  -1 if no PT_DYNAMIC in Phdrs.  */
 123   CORE_ADDR r_debug;
 124 };
 125
 126 struct lwp_info;
 127
 128 struct linux_target_ops
 129 {
 130   /* Architecture-specific setup.  */
 131   void (*arch_setup) (void);
 132
 133   const struct regs_info *(*regs_info) (void);
 134   int (*cannot_fetch_register) (int);
 135
 136   /* Returns 0 if we can store the register, 1 if we can not
 137      store the register, and 2 if failure to store the register
 138      is acceptable.  */
 139   int (*cannot_store_register) (int);
 140
 141   /* Hook to fetch a register in some non-standard way.  Used for
 142      example by backends that have read-only registers with hardcoded
 143      values (e.g., IA64's gr0/fr0/fr1).  Returns true if register
 144      REGNO was supplied, false if not, and we should fallback to the
 145      standard ptrace methods.  */
 146   int (*fetch_register) (struct regcache *regcache, int regno);
 147
 148   CORE_ADDR (*get_pc) (struct regcache *regcache);
 149   void (*set_pc) (struct regcache *regcache, CORE_ADDR newpc);
 150
 151   /* See target.h for details.  */
 152   int (*breakpoint_kind_from_pc) (CORE_ADDR *pcptr);
 153
 154   /* See target.h for details.  */
 155   const gdb_byte *(*sw_breakpoint_from_kind) (int kind, int *size);
 156
 157   /* Find the next possible PCs after the current instruction executes.  */
 158   std::vector<CORE_ADDR> (*get_next_pcs) (struct regcache *regcache);
 159
 160   int decr_pc_after_break;
 161   int (*breakpoint_at) (CORE_ADDR pc);
 162
 163   /* Breakpoint and watchpoint related functions.  See target.h for
 164      comments.  */
 165   int (*supports_z_point_type) (char z_type);
 166   int (*insert_point) (enum raw_bkpt_type type, CORE_ADDR addr,
 167                        int size, struct raw_breakpoint *bp);
 168   int (*remove_point) (enum raw_bkpt_type type, CORE_ADDR addr,
 169                        int size, struct raw_breakpoint *bp);
 170
 171   int (*stopped_by_watchpoint) (void);
 172   CORE_ADDR (*stopped_data_address) (void);
 173
 174   /* Hooks to reformat register data for PEEKUSR/POKEUSR (in particular
 175      for registers smaller than an xfer unit).  */
 176   void (*collect_ptrace_register) (struct regcache *regcache,
 177                                    int regno, char *buf);
 178   void (*supply_ptrace_register) (struct regcache *regcache,
 179                                   int regno, const char *buf);
 180
 181   /* Hook to convert from target format to ptrace format and back.
 182      Returns true if any conversion was done; false otherwise.
 183      If DIRECTION is 1, then copy from INF to NATIVE.
 184      If DIRECTION is 0, copy from NATIVE to INF.  */
 185   int (*siginfo_fixup) (siginfo_t *native, gdb_byte *inf, int direction);
 186
 187   /* Hook to call when a new process is created or attached to.
 188      If extra per-process architecture-specific data is needed,
 189      allocate it here.  */
 190   struct arch_process_info * (*new_process) (void);
 191
 192   /* Hook to call when a new thread is detected.
 193      If extra per-thread architecture-specific data is needed,
 194      allocate it here.  */
 195   void (*new_thread) (struct lwp_info *);
 196
 197   /* Hook to call, if any, when a new fork is attached.  */
 198   void (*new_fork) (struct process_info *parent, struct process_info *child);
 199
 200   /* Hook to call prior to resuming a thread.  */
 201   void (*prepare_to_resume) (struct lwp_info *);
 202
 203   /* Hook to support target specific qSupported.  */
 204   void (*process_qsupported) (char **, int count);
 205
 206   /* Returns true if the low target supports tracepoints.  */
 207   int (*supports_tracepoints) (void);
 208
 209   /* Fill ADDRP with the thread area address of LWPID.  Returns 0 on
 210      success, -1 on failure.  */
 211   int (*get_thread_area) (int lwpid, CORE_ADDR *addrp);
 212
 213   /* Install a fast tracepoint jump pad.  See target.h for
 214      comments.  */
 215   int (*install_fast_tracepoint_jump_pad) (CORE_ADDR tpoint, CORE_ADDR tpaddr,
 216                                            CORE_ADDR collector,
 217                                            CORE_ADDR lockaddr,
 218                                            ULONGEST orig_size,
 219                                            CORE_ADDR *jump_entry,
 220                                            CORE_ADDR *trampoline,
 221                                            ULONGEST *trampoline_size,
 222                                            unsigned char *jjump_pad_insn,
 223                                            ULONGEST *jjump_pad_insn_size,
 224                                            CORE_ADDR *adjusted_insn_addr,
 225                                            CORE_ADDR *adjusted_insn_addr_end,
 226                                            char *err);
 227
 228   /* Return the bytecode operations vector for the current inferior.
 229      Returns NULL if bytecode compilation is not supported.  */
 230   struct emit_ops *(*emit_ops) (void);
 231
 232   /* Return the minimum length of an instruction that can be safely overwritten
 233      for use as a fast tracepoint.  */
 234   int (*get_min_fast_tracepoint_insn_len) (void);
 235
 236   /* Returns true if the low target supports range stepping.  */
 237   int (*supports_range_stepping) (void);
 238
 239   /* See target.h.  */
 240   int (*breakpoint_kind_from_current_state) (CORE_ADDR *pcptr);
 241
 242   /* See target.h.  */
 243   int (*supports_hardware_single_step) (void);
 244
 245   /* Fill *SYSNO with the syscall nr trapped.  Only to be called when
 246      inferior is stopped due to SYSCALL_SIGTRAP.  */
 247   void (*get_syscall_trapinfo) (struct regcache *regcache, int *sysno);
 248
 249   /* See target.h.  */
 250   int (*get_ipa_tdesc_idx) (void);
 251 };
 252
 253 extern struct linux_target_ops the_low_target;
 254
 255 #define get_thread_lwp(thr) ((struct lwp_info *) (inferior_target_data (thr)))
 256 #define get_lwp_thread(lwp) ((lwp)->thread)
 257
 258 /* This struct is recorded in the target_data field of struct thread_info.
 259
 260    On linux ``all_threads'' is keyed by the LWP ID, which we use as the
 261    GDB protocol representation of the thread ID.  Threads also have
 262    a "process ID" (poorly named) which is (presently) the same as the
 263    LWP ID.
 264
 265    There is also ``all_processes'' is keyed by the "overall process ID",
 266    which GNU/Linux calls tgid, "thread group ID".  */
 267
 268 struct lwp_info
 269 {
 270   /* Backlink to the parent object.  */
 271   struct thread_info *thread;
 272
 273   /* If this flag is set, the next SIGSTOP will be ignored (the
 274      process will be immediately resumed).  This means that either we
 275      sent the SIGSTOP to it ourselves and got some other pending event
 276      (so the SIGSTOP is still pending), or that we stopped the
 277      inferior implicitly via PTRACE_ATTACH and have not waited for it
 278      yet.  */
 279   int stop_expected;
 280
 281   /* When this is true, we shall not try to resume this thread, even
 282      if last_resume_kind isn't resume_stop.  */
 283   int suspended;
 284
 285   /* If this flag is set, the lwp is known to be stopped right now (stop
 286      event already received in a wait()).  */
 287   int stopped;
 288
 289   /* Signal whether we are in a SYSCALL_ENTRY or
 290      in a SYSCALL_RETURN event.
 291      Values:
 292      - TARGET_WAITKIND_SYSCALL_ENTRY
 293      - TARGET_WAITKIND_SYSCALL_RETURN */
 294   enum target_waitkind syscall_state;
 295
 296   /* When stopped is set, the last wait status recorded for this lwp.  */
 297   int last_status;
 298
 299   /* If WAITSTATUS->KIND != TARGET_WAITKIND_IGNORE, the waitstatus for
 300      this LWP's last event, to pass to GDB without any further
 301      processing.  This is used to store extended ptrace event
 302      information or exit status until it can be reported to GDB.  */
 303   struct target_waitstatus waitstatus;
 304
 305   /* A pointer to the fork child/parent relative.  Valid only while
 306      the parent fork event is not reported to higher layers.  Used to
 307      avoid wildcard vCont actions resuming a fork child before GDB is
 308      notified about the parent's fork event.  */
 309   struct lwp_info *fork_relative;
 310
 311   /* When stopped is set, this is where the lwp last stopped, with
 312      decr_pc_after_break already accounted for.  If the LWP is
 313      running, this is the address at which the lwp was resumed.  */
 314   CORE_ADDR stop_pc;
 315
 316   /* If this flag is set, STATUS_PENDING is a waitstatus that has not yet
 317      been reported.  */
 318   int status_pending_p;
 319   int status_pending;
 320
 321   /* The reason the LWP last stopped, if we need to track it
 322      (breakpoint, watchpoint, etc.)  */
 323   enum target_stop_reason stop_reason;
 324
 325   /* On architectures where it is possible to know the data address of
 326      a triggered watchpoint, STOPPED_DATA_ADDRESS is non-zero, and
 327      contains such data address.  Only valid if STOPPED_BY_WATCHPOINT
 328      is true.  */
 329   CORE_ADDR stopped_data_address;
 330
 331   /* If this is non-zero, it is a breakpoint to be reinserted at our next
 332      stop (SIGTRAP stops only).  */
 333   CORE_ADDR bp_reinsert;
 334
 335   /* If this flag is set, the last continue operation at the ptrace
 336      level on this process was a single-step.  */
 337   int stepping;
 338
 339   /* Range to single step within.  This is a copy of the step range
 340      passed along the last resume request.  See 'struct
 341      thread_resume'.  */
 342   CORE_ADDR step_range_start;   /* Inclusive */
 343   CORE_ADDR step_range_end;     /* Exclusive */
 344
 345   /* If this flag is set, we need to set the event request flags the
 346      next time we see this LWP stop.  */
 347   int must_set_ptrace_flags;
 348
 349   /* If this is non-zero, it points to a chain of signals which need to
 350      be delivered to this process.  */
 351   struct pending_signals *pending_signals;
 352
 353   /* A link used when resuming.  It is initialized from the resume request,
 354      and then processed and cleared in linux_resume_one_lwp.  */
 355   struct thread_resume *resume;
 356
 357   /* Information bout this lwp's fast tracepoint collection status (is it
 358      currently stopped in the jump pad, and if so, before or at/after the
 359      relocated instruction).  Normally, we won't care about this, but we will
 360      if a signal arrives to this lwp while it is collecting.  */
 361   fast_tpoint_collect_result collecting_fast_tracepoint;
 362
 363   /* If this is non-zero, it points to a chain of signals which need
 364      to be reported to GDB.  These were deferred because the thread
 365      was doing a fast tracepoint collect when they arrived.  */
 366   struct pending_signals *pending_signals_to_report;
 367
 368   /* When collecting_fast_tracepoint is first found to be 1, we insert
 369      a exit-jump-pad-quickly breakpoint.  This is it.  */
 370   struct breakpoint *exit_jump_pad_bkpt;
 371
 372 #ifdef USE_THREAD_DB
 373   int thread_known;
 374   /* The thread handle, used for e.g. TLS access.  Only valid if
 375      THREAD_KNOWN is set.  */
 376   td_thrhandle_t th;
 377 #endif
 378
 379   /* Arch-specific additions.  */
 380   struct arch_lwp_info *arch_private;
 381 };
 382
 383 int linux_pid_exe_is_elf_64_file (int pid, unsigned int *machine);
 384
 385 /* Attach to PTID.  Returns 0 on success, non-zero otherwise (an
 386    errno).  */
 387 int linux_attach_lwp (ptid_t ptid);
 388
 389 struct lwp_info *find_lwp_pid (ptid_t ptid);
 390 /* For linux_stop_lwp see nat/linux-nat.h.  */
 391
 392 #ifdef HAVE_LINUX_REGSETS
 393 void initialize_regsets_info (struct regsets_info *regsets_info);
 394 #endif
 395
 396 void initialize_low_arch (void);
 397
 398 void linux_set_pc_32bit (struct regcache *regcache, CORE_ADDR pc);
 399 CORE_ADDR linux_get_pc_32bit (struct regcache *regcache);
 400
 401 void linux_set_pc_64bit (struct regcache *regcache, CORE_ADDR pc);
 402 CORE_ADDR linux_get_pc_64bit (struct regcache *regcache);
 403
 404 /* From thread-db.c  */
 405 int thread_db_init (void);
 406 void thread_db_detach (struct process_info *);
 407 void thread_db_mourn (struct process_info *);
 408 int thread_db_handle_monitor_command (char *);
 409 int thread_db_get_tls_address (struct thread_info *thread, CORE_ADDR offset,
 410                                CORE_ADDR load_module, CORE_ADDR *address);
 411 int thread_db_look_up_one_symbol (const char *name, CORE_ADDR *addrp);
 412
 413 extern int have_ptrace_getregset;