gdbserver: make linux target op 'cannot_store_register' a predicate function
[deliverable/binutils-gdb.git] / gdbserver / linux-low.h
1 /* Internal interfaces for the GNU/Linux specific target code for gdbserver.
2 Copyright (C) 2002-2020 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 #ifndef GDBSERVER_LINUX_LOW_H
20 #define GDBSERVER_LINUX_LOW_H
21
22 #include "nat/linux-nat.h"
23 #include "nat/gdb_thread_db.h"
24 #include <signal.h>
25
26 #include "gdbthread.h"
27 #include "gdb_proc_service.h"
28
29 /* Included for ptrace type definitions. */
30 #include "nat/linux-ptrace.h"
31 #include "target/waitstatus.h" /* For enum target_stop_reason. */
32 #include "tracepoint.h"
33
34 #define PTRACE_XFER_TYPE long
35
36 #ifdef HAVE_LINUX_REGSETS
37 typedef void (*regset_fill_func) (struct regcache *, void *);
38 typedef void (*regset_store_func) (struct regcache *, const void *);
39 enum regset_type {
40 GENERAL_REGS,
41 FP_REGS,
42 EXTENDED_REGS,
43 OPTIONAL_REGS, /* Do not error if the regset cannot be accessed. */
44 };
45
46 /* The arch's regsets array initializer must be terminated with a NULL
47 regset. */
48 #define NULL_REGSET \
49 { 0, 0, 0, -1, (enum regset_type) -1, NULL, NULL }
50
51 struct regset_info
52 {
53 int get_request, set_request;
54 /* If NT_TYPE isn't 0, it will be passed to ptrace as the 3rd
55 argument and the 4th argument should be "const struct iovec *". */
56 int nt_type;
57 int size;
58 enum regset_type type;
59 regset_fill_func fill_function;
60 regset_store_func store_function;
61 };
62
63 /* Aggregation of all the supported regsets of a given
64 architecture/mode. */
65
66 struct regsets_info
67 {
68 /* The regsets array. */
69 struct regset_info *regsets;
70
71 /* The number of regsets in the REGSETS array. */
72 int num_regsets;
73
74 /* If we get EIO on a regset, do not try it again. Note the set of
75 supported regsets may depend on processor mode on biarch
76 machines. This is a (lazily allocated) array holding one boolean
77 byte (0/1) per regset, with each element corresponding to the
78 regset in the REGSETS array above at the same offset. */
79 char *disabled_regsets;
80 };
81
82 #endif
83
84 /* Mapping between the general-purpose registers in `struct user'
85 format and GDB's register array layout. */
86
87 struct usrregs_info
88 {
89 /* The number of registers accessible. */
90 int num_regs;
91
92 /* The registers map. */
93 int *regmap;
94 };
95
96 /* All info needed to access an architecture/mode's registers. */
97
98 struct regs_info
99 {
100 /* Regset support bitmap: 1 for registers that are transferred as a part
101 of a regset, 0 for ones that need to be handled individually. This
102 can be NULL if all registers are transferred with regsets or regsets
103 are not supported. */
104 unsigned char *regset_bitmap;
105
106 /* Info used when accessing registers with PTRACE_PEEKUSER /
107 PTRACE_POKEUSER. This can be NULL if all registers are
108 transferred with regsets .*/
109 struct usrregs_info *usrregs;
110
111 #ifdef HAVE_LINUX_REGSETS
112 /* Info used when accessing registers with regsets. */
113 struct regsets_info *regsets_info;
114 #endif
115 };
116
117 struct process_info_private
118 {
119 /* Arch-specific additions. */
120 struct arch_process_info *arch_private;
121
122 /* libthread_db-specific additions. Not NULL if this process has loaded
123 thread_db, and it is active. */
124 struct thread_db *thread_db;
125
126 /* &_r_debug. 0 if not yet determined. -1 if no PT_DYNAMIC in Phdrs. */
127 CORE_ADDR r_debug;
128 };
129
130 struct lwp_info;
131
132 struct linux_target_ops
133 {
134 /* Architecture-specific setup. */
135 void (*arch_setup) (void);
136
137 const struct regs_info *(*regs_info) (void);
138
139 /* Return 0 if we can fetch/store the register, 1 if we cannot
140 fetch/store the register. */
141 int (*cannot_fetch_register) (int);
142 int (*cannot_store_register) (int);
143
144 /* Hook to fetch a register in some non-standard way. Used for
145 example by backends that have read-only registers with hardcoded
146 values (e.g., IA64's gr0/fr0/fr1). Returns true if register
147 REGNO was supplied, false if not, and we should fallback to the
148 standard ptrace methods. */
149 int (*fetch_register) (struct regcache *regcache, int regno);
150
151 CORE_ADDR (*get_pc) (struct regcache *regcache);
152 void (*set_pc) (struct regcache *regcache, CORE_ADDR newpc);
153
154 /* See target.h for details. */
155 int (*breakpoint_kind_from_pc) (CORE_ADDR *pcptr);
156
157 /* See target.h for details. */
158 const gdb_byte *(*sw_breakpoint_from_kind) (int kind, int *size);
159
160 /* Find the next possible PCs after the current instruction executes. */
161 std::vector<CORE_ADDR> (*get_next_pcs) (struct regcache *regcache);
162
163 int decr_pc_after_break;
164 int (*breakpoint_at) (CORE_ADDR pc);
165
166 /* Breakpoint and watchpoint related functions. See target.h for
167 comments. */
168 int (*supports_z_point_type) (char z_type);
169 int (*insert_point) (enum raw_bkpt_type type, CORE_ADDR addr,
170 int size, struct raw_breakpoint *bp);
171 int (*remove_point) (enum raw_bkpt_type type, CORE_ADDR addr,
172 int size, struct raw_breakpoint *bp);
173
174 int (*stopped_by_watchpoint) (void);
175 CORE_ADDR (*stopped_data_address) (void);
176
177 /* Hooks to reformat register data for PEEKUSR/POKEUSR (in particular
178 for registers smaller than an xfer unit). */
179 void (*collect_ptrace_register) (struct regcache *regcache,
180 int regno, char *buf);
181 void (*supply_ptrace_register) (struct regcache *regcache,
182 int regno, const char *buf);
183
184 /* Hook to convert from target format to ptrace format and back.
185 Returns true if any conversion was done; false otherwise.
186 If DIRECTION is 1, then copy from INF to NATIVE.
187 If DIRECTION is 0, copy from NATIVE to INF. */
188 int (*siginfo_fixup) (siginfo_t *native, gdb_byte *inf, int direction);
189
190 /* Hook to call when a new process is created or attached to.
191 If extra per-process architecture-specific data is needed,
192 allocate it here. */
193 struct arch_process_info * (*new_process) (void);
194
195 /* Hook to call when a process is being deleted. If extra per-process
196 architecture-specific data is needed, delete it here. */
197 void (*delete_process) (struct arch_process_info *info);
198
199 /* Hook to call when a new thread is detected.
200 If extra per-thread architecture-specific data is needed,
201 allocate it here. */
202 void (*new_thread) (struct lwp_info *);
203
204 /* Hook to call when a thread is being deleted. If extra per-thread
205 architecture-specific data is needed, delete it here. */
206 void (*delete_thread) (struct arch_lwp_info *);
207
208 /* Hook to call, if any, when a new fork is attached. */
209 void (*new_fork) (struct process_info *parent, struct process_info *child);
210
211 /* Hook to call prior to resuming a thread. */
212 void (*prepare_to_resume) (struct lwp_info *);
213
214 /* Hook to support target specific qSupported. */
215 void (*process_qsupported) (char **, int count);
216
217 /* Returns true if the low target supports tracepoints. */
218 int (*supports_tracepoints) (void);
219
220 /* Fill ADDRP with the thread area address of LWPID. Returns 0 on
221 success, -1 on failure. */
222 int (*get_thread_area) (int lwpid, CORE_ADDR *addrp);
223
224 /* Install a fast tracepoint jump pad. See target.h for
225 comments. */
226 int (*install_fast_tracepoint_jump_pad) (CORE_ADDR tpoint, CORE_ADDR tpaddr,
227 CORE_ADDR collector,
228 CORE_ADDR lockaddr,
229 ULONGEST orig_size,
230 CORE_ADDR *jump_entry,
231 CORE_ADDR *trampoline,
232 ULONGEST *trampoline_size,
233 unsigned char *jjump_pad_insn,
234 ULONGEST *jjump_pad_insn_size,
235 CORE_ADDR *adjusted_insn_addr,
236 CORE_ADDR *adjusted_insn_addr_end,
237 char *err);
238
239 /* Return the bytecode operations vector for the current inferior.
240 Returns NULL if bytecode compilation is not supported. */
241 struct emit_ops *(*emit_ops) (void);
242
243 /* Return the minimum length of an instruction that can be safely overwritten
244 for use as a fast tracepoint. */
245 int (*get_min_fast_tracepoint_insn_len) (void);
246
247 /* Returns true if the low target supports range stepping. */
248 int (*supports_range_stepping) (void);
249
250 /* See target.h. */
251 int (*breakpoint_kind_from_current_state) (CORE_ADDR *pcptr);
252
253 /* See target.h. */
254 int (*supports_hardware_single_step) (void);
255
256 /* Fill *SYSNO with the syscall nr trapped. Only to be called when
257 inferior is stopped due to SYSCALL_SIGTRAP. */
258 void (*get_syscall_trapinfo) (struct regcache *regcache, int *sysno);
259
260 /* See target.h. */
261 int (*get_ipa_tdesc_idx) (void);
262 };
263
264 extern struct linux_target_ops the_low_target;
265
266 /* Target ops definitions for a Linux target. */
267
268 class linux_process_target : public process_stratum_target
269 {
270 public:
271
272 int create_inferior (const char *program,
273 const std::vector<char *> &program_args) override;
274
275 void post_create_inferior () override;
276
277 int attach (unsigned long pid) override;
278
279 int kill (process_info *proc) override;
280
281 int detach (process_info *proc) override;
282
283 void mourn (process_info *proc) override;
284
285 void join (int pid) override;
286
287 bool thread_alive (ptid_t pid) override;
288
289 void resume (thread_resume *resume_info, size_t n) override;
290
291 ptid_t wait (ptid_t ptid, target_waitstatus *status,
292 int options) override;
293
294 void fetch_registers (regcache *regcache, int regno) override;
295
296 void store_registers (regcache *regcache, int regno) override;
297
298 int prepare_to_access_memory () override;
299
300 void done_accessing_memory () override;
301
302 int read_memory (CORE_ADDR memaddr, unsigned char *myaddr,
303 int len) override;
304
305 int write_memory (CORE_ADDR memaddr, const unsigned char *myaddr,
306 int len) override;
307
308 void look_up_symbols () override;
309
310 void request_interrupt () override;
311
312 bool supports_read_auxv () override;
313
314 int read_auxv (CORE_ADDR offset, unsigned char *myaddr,
315 unsigned int len) override;
316
317 bool supports_z_point_type (char z_type) override;
318
319 int insert_point (enum raw_bkpt_type type, CORE_ADDR addr,
320 int size, raw_breakpoint *bp) override;
321
322 int remove_point (enum raw_bkpt_type type, CORE_ADDR addr,
323 int size, raw_breakpoint *bp) override;
324
325 bool stopped_by_sw_breakpoint () override;
326
327 bool supports_stopped_by_sw_breakpoint () override;
328
329 bool stopped_by_hw_breakpoint () override;
330
331 bool supports_stopped_by_hw_breakpoint () override;
332
333 bool supports_hardware_single_step () override;
334
335 bool stopped_by_watchpoint () override;
336
337 CORE_ADDR stopped_data_address () override;
338
339 bool supports_read_offsets () override;
340
341 int read_offsets (CORE_ADDR *text, CORE_ADDR *data) override;
342
343 bool supports_get_tls_address () override;
344
345 int get_tls_address (thread_info *thread, CORE_ADDR offset,
346 CORE_ADDR load_module, CORE_ADDR *address) override;
347
348 bool supports_qxfer_osdata () override;
349
350 int qxfer_osdata (const char *annex, unsigned char *readbuf,
351 unsigned const char *writebuf,
352 CORE_ADDR offset, int len) override;
353
354 bool supports_qxfer_siginfo () override;
355
356 int qxfer_siginfo (const char *annex, unsigned char *readbuf,
357 unsigned const char *writebuf,
358 CORE_ADDR offset, int len) override;
359
360 bool supports_non_stop () override;
361
362 bool async (bool enable) override;
363
364 int start_non_stop (bool enable) override;
365
366 bool supports_multi_process () override;
367
368 bool supports_fork_events () override;
369
370 bool supports_vfork_events () override;
371
372 bool supports_exec_events () override;
373
374 void handle_new_gdb_connection () override;
375
376 int handle_monitor_command (char *mon) override;
377
378 int core_of_thread (ptid_t ptid) override;
379
380 #if defined PT_GETDSBT || defined PTRACE_GETFDPIC
381 bool supports_read_loadmap () override;
382
383 int read_loadmap (const char *annex, CORE_ADDR offset,
384 unsigned char *myaddr, unsigned int len) override;
385 #endif
386
387 void process_qsupported (char **features, int count) override;
388
389 bool supports_tracepoints () override;
390
391 CORE_ADDR read_pc (regcache *regcache) override;
392
393 void write_pc (regcache *regcache, CORE_ADDR pc) override;
394
395 bool supports_thread_stopped () override;
396
397 bool thread_stopped (thread_info *thread) override;
398
399 void pause_all (bool freeze) override;
400
401 void unpause_all (bool unfreeze) override;
402
403 void stabilize_threads () override;
404
405 bool supports_fast_tracepoints () override;
406
407 int install_fast_tracepoint_jump_pad (CORE_ADDR tpoint,
408 CORE_ADDR tpaddr,
409 CORE_ADDR collector,
410 CORE_ADDR lockaddr,
411 ULONGEST orig_size,
412 CORE_ADDR *jump_entry,
413 CORE_ADDR *trampoline,
414 ULONGEST *trampoline_size,
415 unsigned char *jjump_pad_insn,
416 ULONGEST *jjump_pad_insn_size,
417 CORE_ADDR *adjusted_insn_addr,
418 CORE_ADDR *adjusted_insn_addr_end,
419 char *err) override;
420
421 int get_min_fast_tracepoint_insn_len () override;
422
423 struct emit_ops *emit_ops () override;
424
425 bool supports_disable_randomization () override;
426
427 bool supports_qxfer_libraries_svr4 () override;
428
429 int qxfer_libraries_svr4 (const char *annex,
430 unsigned char *readbuf,
431 unsigned const char *writebuf,
432 CORE_ADDR offset, int len) override;
433
434 bool supports_agent () override;
435
436 #ifdef HAVE_LINUX_BTRACE
437 btrace_target_info *enable_btrace (ptid_t ptid,
438 const btrace_config *conf) override;
439
440 int disable_btrace (btrace_target_info *tinfo) override;
441
442 int read_btrace (btrace_target_info *tinfo, buffer *buf,
443 enum btrace_read_type type) override;
444
445 int read_btrace_conf (const btrace_target_info *tinfo,
446 buffer *buf) override;
447 #endif
448
449 bool supports_range_stepping () override;
450
451 bool supports_pid_to_exec_file () override;
452
453 char *pid_to_exec_file (int pid) override;
454
455 bool supports_multifs () override;
456
457 int multifs_open (int pid, const char *filename, int flags,
458 mode_t mode) override;
459
460 int multifs_unlink (int pid, const char *filename) override;
461
462 ssize_t multifs_readlink (int pid, const char *filename, char *buf,
463 size_t bufsiz) override;
464
465 int breakpoint_kind_from_pc (CORE_ADDR *pcptr) override;
466
467 const gdb_byte *sw_breakpoint_from_kind (int kind, int *size) override;
468
469 int breakpoint_kind_from_current_state (CORE_ADDR *pcptr) override;
470
471 const char *thread_name (ptid_t thread) override;
472
473 #if USE_THREAD_DB
474 bool thread_handle (ptid_t ptid, gdb_byte **handle,
475 int *handle_len) override;
476 #endif
477
478 bool supports_software_single_step () override;
479
480 bool supports_catch_syscall () override;
481
482 int get_ipa_tdesc_idx () override;
483 };
484
485 #define get_thread_lwp(thr) ((struct lwp_info *) (thread_target_data (thr)))
486 #define get_lwp_thread(lwp) ((lwp)->thread)
487
488 /* This struct is recorded in the target_data field of struct thread_info.
489
490 On linux ``all_threads'' is keyed by the LWP ID, which we use as the
491 GDB protocol representation of the thread ID. Threads also have
492 a "process ID" (poorly named) which is (presently) the same as the
493 LWP ID.
494
495 There is also ``all_processes'' is keyed by the "overall process ID",
496 which GNU/Linux calls tgid, "thread group ID". */
497
498 struct lwp_info
499 {
500 /* Backlink to the parent object. */
501 struct thread_info *thread;
502
503 /* If this flag is set, the next SIGSTOP will be ignored (the
504 process will be immediately resumed). This means that either we
505 sent the SIGSTOP to it ourselves and got some other pending event
506 (so the SIGSTOP is still pending), or that we stopped the
507 inferior implicitly via PTRACE_ATTACH and have not waited for it
508 yet. */
509 int stop_expected;
510
511 /* When this is true, we shall not try to resume this thread, even
512 if last_resume_kind isn't resume_stop. */
513 int suspended;
514
515 /* If this flag is set, the lwp is known to be stopped right now (stop
516 event already received in a wait()). */
517 int stopped;
518
519 /* Signal whether we are in a SYSCALL_ENTRY or
520 in a SYSCALL_RETURN event.
521 Values:
522 - TARGET_WAITKIND_SYSCALL_ENTRY
523 - TARGET_WAITKIND_SYSCALL_RETURN */
524 enum target_waitkind syscall_state;
525
526 /* When stopped is set, the last wait status recorded for this lwp. */
527 int last_status;
528
529 /* If WAITSTATUS->KIND != TARGET_WAITKIND_IGNORE, the waitstatus for
530 this LWP's last event, to pass to GDB without any further
531 processing. This is used to store extended ptrace event
532 information or exit status until it can be reported to GDB. */
533 struct target_waitstatus waitstatus;
534
535 /* A pointer to the fork child/parent relative. Valid only while
536 the parent fork event is not reported to higher layers. Used to
537 avoid wildcard vCont actions resuming a fork child before GDB is
538 notified about the parent's fork event. */
539 struct lwp_info *fork_relative;
540
541 /* When stopped is set, this is where the lwp last stopped, with
542 decr_pc_after_break already accounted for. If the LWP is
543 running, this is the address at which the lwp was resumed. */
544 CORE_ADDR stop_pc;
545
546 /* If this flag is set, STATUS_PENDING is a waitstatus that has not yet
547 been reported. */
548 int status_pending_p;
549 int status_pending;
550
551 /* The reason the LWP last stopped, if we need to track it
552 (breakpoint, watchpoint, etc.) */
553 enum target_stop_reason stop_reason;
554
555 /* On architectures where it is possible to know the data address of
556 a triggered watchpoint, STOPPED_DATA_ADDRESS is non-zero, and
557 contains such data address. Only valid if STOPPED_BY_WATCHPOINT
558 is true. */
559 CORE_ADDR stopped_data_address;
560
561 /* If this is non-zero, it is a breakpoint to be reinserted at our next
562 stop (SIGTRAP stops only). */
563 CORE_ADDR bp_reinsert;
564
565 /* If this flag is set, the last continue operation at the ptrace
566 level on this process was a single-step. */
567 int stepping;
568
569 /* Range to single step within. This is a copy of the step range
570 passed along the last resume request. See 'struct
571 thread_resume'. */
572 CORE_ADDR step_range_start; /* Inclusive */
573 CORE_ADDR step_range_end; /* Exclusive */
574
575 /* If this flag is set, we need to set the event request flags the
576 next time we see this LWP stop. */
577 int must_set_ptrace_flags;
578
579 /* If this is non-zero, it points to a chain of signals which need to
580 be delivered to this process. */
581 struct pending_signals *pending_signals;
582
583 /* A link used when resuming. It is initialized from the resume request,
584 and then processed and cleared in linux_resume_one_lwp. */
585 struct thread_resume *resume;
586
587 /* Information bout this lwp's fast tracepoint collection status (is it
588 currently stopped in the jump pad, and if so, before or at/after the
589 relocated instruction). Normally, we won't care about this, but we will
590 if a signal arrives to this lwp while it is collecting. */
591 fast_tpoint_collect_result collecting_fast_tracepoint;
592
593 /* If this is non-zero, it points to a chain of signals which need
594 to be reported to GDB. These were deferred because the thread
595 was doing a fast tracepoint collect when they arrived. */
596 struct pending_signals *pending_signals_to_report;
597
598 /* When collecting_fast_tracepoint is first found to be 1, we insert
599 a exit-jump-pad-quickly breakpoint. This is it. */
600 struct breakpoint *exit_jump_pad_bkpt;
601
602 #ifdef USE_THREAD_DB
603 int thread_known;
604 /* The thread handle, used for e.g. TLS access. Only valid if
605 THREAD_KNOWN is set. */
606 td_thrhandle_t th;
607
608 /* The pthread_t handle. */
609 thread_t thread_handle;
610 #endif
611
612 /* Arch-specific additions. */
613 struct arch_lwp_info *arch_private;
614 };
615
616 int linux_pid_exe_is_elf_64_file (int pid, unsigned int *machine);
617
618 /* Attach to PTID. Returns 0 on success, non-zero otherwise (an
619 errno). */
620 int linux_attach_lwp (ptid_t ptid);
621
622 struct lwp_info *find_lwp_pid (ptid_t ptid);
623 /* For linux_stop_lwp see nat/linux-nat.h. */
624
625 #ifdef HAVE_LINUX_REGSETS
626 void initialize_regsets_info (struct regsets_info *regsets_info);
627 #endif
628
629 void initialize_low_arch (void);
630
631 void linux_set_pc_32bit (struct regcache *regcache, CORE_ADDR pc);
632 CORE_ADDR linux_get_pc_32bit (struct regcache *regcache);
633
634 void linux_set_pc_64bit (struct regcache *regcache, CORE_ADDR pc);
635 CORE_ADDR linux_get_pc_64bit (struct regcache *regcache);
636
637 /* From thread-db.c */
638 int thread_db_init (void);
639 void thread_db_detach (struct process_info *);
640 void thread_db_mourn (struct process_info *);
641 int thread_db_handle_monitor_command (char *);
642 int thread_db_get_tls_address (struct thread_info *thread, CORE_ADDR offset,
643 CORE_ADDR load_module, CORE_ADDR *address);
644 int thread_db_look_up_one_symbol (const char *name, CORE_ADDR *addrp);
645
646 /* Called from linux-low.c when a clone event is detected. Upon entry,
647 both the clone and the parent should be stopped. This function does
648 whatever is required have the clone under thread_db's control. */
649
650 void thread_db_notice_clone (struct thread_info *parent_thr, ptid_t child_ptid);
651
652 bool thread_db_thread_handle (ptid_t ptid, gdb_byte **handle, int *handle_len);
653
654 extern int have_ptrace_getregset;
655
656 /* Search for the value with type MATCH in the auxv vector with
657 entries of length WORDSIZE bytes. If found, store the value in
658 *VALP and return 1. If not found or if there is an error, return
659 0. */
660
661 int linux_get_auxv (int wordsize, CORE_ADDR match,
662 CORE_ADDR *valp);
663
664 /* Fetch the AT_HWCAP entry from the auxv vector, where entries are length
665 WORDSIZE. If no entry was found, return zero. */
666
667 CORE_ADDR linux_get_hwcap (int wordsize);
668
669 /* Fetch the AT_HWCAP2 entry from the auxv vector, where entries are length
670 WORDSIZE. If no entry was found, return zero. */
671
672 CORE_ADDR linux_get_hwcap2 (int wordsize);
673
674 #endif /* GDBSERVER_LINUX_LOW_H */
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