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linux-low.h
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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 
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 .*/
100 
101 #ifdef HAVE_LINUX_REGSETS
102  /* Info used when accessing registers with regsets. */
103  struct regsets_info *regsets_info;
104 #endif
105 };
106 
108 {
109  /* Arch-specific additions. */
111 
112  /* libthread_db-specific additions. Not NULL if this process has loaded
113  thread_db, and it is active. */
115 
116  /* &_r_debug. 0 if not yet determined. -1 if no PT_DYNAMIC in Phdrs. */
118 
119  /* This flag is true iff we've just created or attached to the first
120  LWP of this process but it has not stopped yet. As soon as it
121  does, we need to call the low target's arch_setup callback. */
123 };
124 
125 struct lwp_info;
126 
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  const unsigned char *breakpoint;
152 
155 
156  /* Breakpoint and watchpoint related functions. See target.h for
157  comments. */
158  int (*supports_z_point_type) (char z_type);
159  int (*insert_point) (enum raw_bkpt_type type, CORE_ADDR addr,
160  int size, struct raw_breakpoint *bp);
161  int (*remove_point) (enum raw_bkpt_type type, CORE_ADDR addr,
162  int size, struct raw_breakpoint *bp);
163 
164  int (*stopped_by_watchpoint) (void);
166 
167  /* Hooks to reformat register data for PEEKUSR/POKEUSR (in particular
168  for registers smaller than an xfer unit). */
169  void (*collect_ptrace_register) (struct regcache *regcache,
170  int regno, char *buf);
171  void (*supply_ptrace_register) (struct regcache *regcache,
172  int regno, const char *buf);
173 
174  /* Hook to convert from target format to ptrace format and back.
175  Returns true if any conversion was done; false otherwise.
176  If DIRECTION is 1, then copy from INF to NATIVE.
177  If DIRECTION is 0, copy from NATIVE to INF. */
178  int (*siginfo_fixup) (siginfo_t *native, void *inf, int direction);
179 
180  /* Hook to call when a new process is created or attached to.
181  If extra per-process architecture-specific data is needed,
182  allocate it here. */
183  struct arch_process_info * (*new_process) (void);
184 
185  /* Hook to call when a new thread is detected.
186  If extra per-thread architecture-specific data is needed,
187  allocate it here. */
188  void (*new_thread) (struct lwp_info *);
189 
190  /* Hook to call, if any, when a new fork is attached. */
191  void (*new_fork) (struct process_info *parent, struct process_info *child);
192 
193  /* Hook to call prior to resuming a thread. */
194  void (*prepare_to_resume) (struct lwp_info *);
195 
196  /* Hook to support target specific qSupported. */
197  void (*process_qsupported) (const char *);
198 
199  /* Returns true if the low target supports tracepoints. */
200  int (*supports_tracepoints) (void);
201 
202  /* Fill ADDRP with the thread area address of LWPID. Returns 0 on
203  success, -1 on failure. */
204  int (*get_thread_area) (int lwpid, CORE_ADDR *addrp);
205 
206  /* Install a fast tracepoint jump pad. See target.h for
207  comments. */
209  CORE_ADDR collector,
210  CORE_ADDR lockaddr,
211  ULONGEST orig_size,
212  CORE_ADDR *jump_entry,
213  CORE_ADDR *trampoline,
214  ULONGEST *trampoline_size,
215  unsigned char *jjump_pad_insn,
216  ULONGEST *jjump_pad_insn_size,
217  CORE_ADDR *adjusted_insn_addr,
218  CORE_ADDR *adjusted_insn_addr_end,
219  char *err);
220 
221  /* Return the bytecode operations vector for the current inferior.
222  Returns NULL if bytecode compilation is not supported. */
223  struct emit_ops *(*emit_ops) (void);
224 
225  /* Return the minimum length of an instruction that can be safely overwritten
226  for use as a fast tracepoint. */
228 
229  /* Returns true if the low target supports range stepping. */
230  int (*supports_range_stepping) (void);
231 };
232 
233 extern struct linux_target_ops the_low_target;
234 
235 #define get_thread_lwp(thr) ((struct lwp_info *) (inferior_target_data (thr)))
236 #define get_lwp_thread(lwp) ((lwp)->thread)
237 
238 /* This struct is recorded in the target_data field of struct thread_info.
239 
240  On linux ``all_threads'' is keyed by the LWP ID, which we use as the
241  GDB protocol representation of the thread ID. Threads also have
242  a "process ID" (poorly named) which is (presently) the same as the
243  LWP ID.
244 
245  There is also ``all_processes'' is keyed by the "overall process ID",
246  which GNU/Linux calls tgid, "thread group ID". */
247 
248 struct lwp_info
249 {
250  /* Backlink to the parent object. */
252 
253  /* If this flag is set, the next SIGSTOP will be ignored (the
254  process will be immediately resumed). This means that either we
255  sent the SIGSTOP to it ourselves and got some other pending event
256  (so the SIGSTOP is still pending), or that we stopped the
257  inferior implicitly via PTRACE_ATTACH and have not waited for it
258  yet. */
260 
261  /* When this is true, we shall not try to resume this thread, even
262  if last_resume_kind isn't resume_stop. */
264 
265  /* If this flag is set, the lwp is known to be stopped right now (stop
266  event already received in a wait()). */
267  int stopped;
268 
269  /* When stopped is set, the last wait status recorded for this lwp. */
271 
272  /* If WAITSTATUS->KIND != TARGET_WAITKIND_IGNORE, the waitstatus for
273  this LWP's last event, to pass to GDB without any further
274  processing. This is used to store extended ptrace event
275  information or exit status until it can be reported to GDB. */
276  struct target_waitstatus waitstatus;
277 
278  /* When stopped is set, this is where the lwp last stopped, with
279  decr_pc_after_break already accounted for. If the LWP is
280  running, this is the address at which the lwp was resumed. */
282 
283  /* If this flag is set, STATUS_PENDING is a waitstatus that has not yet
284  been reported. */
287 
288  /* The reason the LWP last stopped, if we need to track it
289  (breakpoint, watchpoint, etc.) */
290  enum target_stop_reason stop_reason;
291 
292  /* On architectures where it is possible to know the data address of
293  a triggered watchpoint, STOPPED_DATA_ADDRESS is non-zero, and
294  contains such data address. Only valid if STOPPED_BY_WATCHPOINT
295  is true. */
297 
298  /* If this is non-zero, it is a breakpoint to be reinserted at our next
299  stop (SIGTRAP stops only). */
301 
302  /* If this flag is set, the last continue operation at the ptrace
303  level on this process was a single-step. */
304  int stepping;
305 
306  /* Range to single step within. This is a copy of the step range
307  passed along the last resume request. See 'struct
308  thread_resume'. */
309  CORE_ADDR step_range_start; /* Inclusive */
310  CORE_ADDR step_range_end; /* Exclusive */
311 
312  /* If this flag is set, we need to set the event request flags the
313  next time we see this LWP stop. */
315 
316  /* If this is non-zero, it points to a chain of signals which need to
317  be delivered to this process. */
319 
320  /* A link used when resuming. It is initialized from the resume request,
321  and then processed and cleared in linux_resume_one_lwp. */
323 
324  /* True if it is known that this lwp is presently collecting a fast
325  tracepoint (it is in the jump pad or in some code that will
326  return to the jump pad. Normally, we won't care about this, but
327  we will if a signal arrives to this lwp while it is
328  collecting. */
330 
331  /* If this is non-zero, it points to a chain of signals which need
332  to be reported to GDB. These were deferred because the thread
333  was doing a fast tracepoint collect when they arrived. */
334  struct pending_signals *pending_signals_to_report;
335 
336  /* When collecting_fast_tracepoint is first found to be 1, we insert
337  a exit-jump-pad-quickly breakpoint. This is it. */
339 
340  /* True if the LWP was seen stop at an internal breakpoint and needs
341  stepping over later when it is resumed. */
343 
344 #ifdef USE_THREAD_DB
345  int thread_known;
346  /* The thread handle, used for e.g. TLS access. Only valid if
347  THREAD_KNOWN is set. */
348  td_thrhandle_t th;
349 #endif
350 
351  /* Arch-specific additions. */
353 };
354 
355 int linux_pid_exe_is_elf_64_file (int pid, unsigned int *machine);
356 
357 /* Attach to PTID. Returns 0 on success, non-zero otherwise (an
358  errno). */
360 
361 struct lwp_info *find_lwp_pid (ptid_t ptid);
362 /* For linux_stop_lwp see nat/linux-nat.h. */
363 
364 #ifdef HAVE_LINUX_REGSETS
365 void initialize_regsets_info (struct regsets_info *regsets_info);
366 #endif
367 
368 void initialize_low_arch (void);
369 
370 /* From thread-db.c */
371 int thread_db_init (int use_events);
372 void thread_db_detach (struct process_info *);
373 void thread_db_mourn (struct process_info *);
376  CORE_ADDR load_module, CORE_ADDR *address);
377 int thread_db_look_up_one_symbol (const char *name, CORE_ADDR *addrp);
struct arch_lwp_info * arch_private
Definition: linux-low.h:352
regset_type
Definition: nto-low.h:24
int linux_attach_lwp(ptid_t ptid)
Definition: linux-low.c:846
struct usrregs_info * usrregs
Definition: linux-low.h:99
bfd_vma CORE_ADDR
Definition: common-types.h:41
void(* new_fork)(struct process_info *parent, struct process_info *child)
Definition: linux-low.h:191
struct lwp_info * find_lwp_pid(ptid_t ptid)
Definition: linux-low.c:1531
int(* cannot_store_register)(int)
Definition: linux-low.h:138
int(* supports_z_point_type)(char z_type)
Definition: linux-low.h:158
void thread_db_mourn(struct process_info *)
Definition: thread-db.c:972
void initialize_low_arch(void)
int decr_pc_after_break
Definition: linux-low.h:153
int collecting_fast_tracepoint
Definition: linux-low.h:329
const char * name
Definition: tracepoint.c:178
int(* stopped_by_watchpoint)(void)
Definition: linux-low.h:164
int thread_db_init(int use_events)
Definition: thread-db.c:836
int(* breakpoint_at)(CORE_ADDR pc)
Definition: linux-low.h:154
const unsigned char * breakpoint
Definition: linux-low.h:149
int(* fetch_register)(struct regcache *regcache, int regno)
Definition: linux-low.h:145
int need_step_over
Definition: linux-low.h:342
Definition: ptid.h:35
struct target_waitstatus waitstatus
Definition: linux-low.h:276
int must_set_ptrace_flags
Definition: linux-low.h:314
struct arch_process_info * arch_private
Definition: linux-low.h:110
void(* set_pc)(struct regcache *regcache, CORE_ADDR newpc)
Definition: linux-low.h:148
unsigned char * regset_bitmap
Definition: linux-low.h:94
CORE_ADDR step_range_end
Definition: linux-low.h:310
raw_bkpt_type
Definition: mem-break.h:40
CORE_ADDR bp_reinsert
Definition: linux-low.h:300
int(* get_thread_area)(int lwpid, CORE_ADDR *addrp)
Definition: linux-low.h:204
struct thread_db * thread_db
Definition: linux-low.h:114
struct linux_target_ops the_low_target
int(* cannot_fetch_register)(int)
Definition: linux-low.h:133
int offset
Definition: tracepoint.c:179
int stop_expected
Definition: linux-low.h:259
int linux_pid_exe_is_elf_64_file(int pid, unsigned int *machine)
Definition: linux-low.c:379
CORE_ADDR step_range_start
Definition: linux-low.h:309
int last_status
Definition: linux-low.h:270
int thread_db_get_tls_address(struct thread_info *thread, CORE_ADDR offset, CORE_ADDR load_module, CORE_ADDR *address)
Definition: thread-db.c:504
void(* collect_ptrace_register)(struct regcache *regcache, int regno, char *buf)
Definition: linux-low.h:169
int status_pending
Definition: linux-low.h:286
CORE_ADDR(* stopped_data_address)(void)
Definition: linux-low.h:165
int stopped
Definition: linux-low.h:267
void(* process_qsupported)(const char *)
Definition: linux-low.h:197
void thread_db_detach(struct process_info *)
Definition: thread-db.c:958
struct pending_signals * pending_signals
Definition: linux-low.h:318
int(* insert_point)(enum raw_bkpt_type type, CORE_ADDR addr, int size, struct raw_breakpoint *bp)
Definition: linux-low.h:159
CORE_ADDR stopped_data_address
Definition: linux-low.h:296
int(* remove_point)(enum raw_bkpt_type type, CORE_ADDR addr, int size, struct raw_breakpoint *bp)
Definition: linux-low.h:161
Definition: ax.h:91
void(* prepare_to_resume)(struct lwp_info *)
Definition: linux-low.h:194
int(* supports_tracepoints)(void)
Definition: linux-low.h:200
int(* siginfo_fixup)(siginfo_t *native, void *inf, int direction)
Definition: linux-low.h:178
int(* install_fast_tracepoint_jump_pad)(CORE_ADDR tpoint, CORE_ADDR tpaddr, CORE_ADDR collector, CORE_ADDR lockaddr, ULONGEST orig_size, CORE_ADDR *jump_entry, CORE_ADDR *trampoline, ULONGEST *trampoline_size, unsigned char *jjump_pad_insn, ULONGEST *jjump_pad_insn_size, CORE_ADDR *adjusted_insn_addr, CORE_ADDR *adjusted_insn_addr_end, char *err)
Definition: linux-low.h:208
int stepping
Definition: linux-low.h:304
int thread_db_look_up_one_symbol(const char *name, CORE_ADDR *addrp)
Definition: thread-db.c:490
int num_regs
Definition: linux-low.h:80
struct thread_resume * resume
Definition: linux-low.h:322
int(* supports_range_stepping)(void)
Definition: linux-low.h:230
struct pending_signals * pending_signals_to_report
Definition: linux-low.h:334
void(* new_thread)(struct lwp_info *)
Definition: linux-low.h:188
int thread_db_handle_monitor_command(char *)
Definition: thread-db.c:1001
enum target_stop_reason stop_reason
Definition: linux-low.h:290
unsigned long long ULONGEST
Definition: common-types.h:53
int status_pending_p
Definition: linux-low.h:285
struct breakpoint * exit_jump_pad_bkpt
Definition: linux-low.h:338
void(* supply_ptrace_register)(struct regcache *regcache, int regno, const char *buf)
Definition: linux-low.h:171
int(* get_min_fast_tracepoint_insn_len)(void)
Definition: linux-low.h:227
CORE_ADDR(* breakpoint_reinsert_addr)(void)
Definition: linux-low.h:151
void(* arch_setup)(void)
Definition: linux-low.h:130
CORE_ADDR stop_pc
Definition: linux-low.h:281
int * regmap
Definition: linux-low.h:83
int suspended
Definition: linux-low.h:263
struct thread_info * thread
Definition: linux-low.h:251
CORE_ADDR(* get_pc)(struct regcache *regcache)
Definition: linux-low.h:147