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1 | /* Ada Ravenscar thread support. | |
2 | ||
3 | Copyright (C) 2004-2025 Free Software Foundation, Inc. | |
4 | ||
5 | This file is part of GDB. | |
6 | ||
7 | This program is free software; you can redistribute it and/or modify | |
8 | it under the terms of the GNU General Public License as published by | |
9 | the Free Software Foundation; either version 3 of the License, or | |
10 | (at your option) any later version. | |
11 | ||
12 | This program is distributed in the hope that it will be useful, | |
13 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
14 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
15 | GNU General Public License for more details. | |
16 | ||
17 | You should have received a copy of the GNU General Public License | |
18 | along with this program. If not, see <http://www.gnu.org/licenses/>. */ | |
19 | ||
20 | #include "extract-store-integer.h" | |
21 | #include "gdbcore.h" | |
22 | #include "gdbthread.h" | |
23 | #include "ada-lang.h" | |
24 | #include "target.h" | |
25 | #include "inferior.h" | |
26 | #include "command.h" | |
27 | #include "ravenscar-thread.h" | |
28 | #include "observable.h" | |
29 | #include "cli/cli-cmds.h" | |
30 | #include "top.h" | |
31 | #include "regcache.h" | |
32 | #include "objfiles.h" | |
33 | #include "gdbsupport/unordered_map.h" | |
34 | ||
35 | /* This module provides support for "Ravenscar" tasks (Ada) when | |
36 | debugging on bare-metal targets. | |
37 | ||
38 | The typical situation is when debugging a bare-metal target over | |
39 | the remote protocol. In that situation, the system does not know | |
40 | about high-level concepts such as threads, only about some code | |
41 | running on one or more CPUs. And since the remote protocol does not | |
42 | provide any handling for CPUs, the de facto standard for handling | |
43 | them is to have one thread per CPU, where the thread's ptid has | |
44 | its lwp field set to the CPU number (eg: 1 for the first CPU, | |
45 | 2 for the second one, etc). This module will make that assumption. | |
46 | ||
47 | This module then creates and maintains the list of threads based | |
48 | on the list of Ada tasks, with one thread per Ada task. The convention | |
49 | is that threads corresponding to the CPUs (see assumption above) | |
50 | have a ptid_t of the form (PID, LWP, 0), while threads corresponding | |
51 | to our Ada tasks have a ptid_t of the form (PID, 0, TID) where TID | |
52 | is the Ada task's ID as extracted from Ada runtime information. | |
53 | ||
54 | Switching to a given Ada task (or its underlying thread) is performed | |
55 | by fetching the registers of that task from the memory area where | |
56 | the registers were saved. For any of the other operations, the | |
57 | operation is performed by first finding the CPU on which the task | |
58 | is running, switching to its corresponding ptid, and then performing | |
59 | the operation on that ptid using the target beneath us. */ | |
60 | ||
61 | /* If true, ravenscar task support is enabled. */ | |
62 | static bool ravenscar_task_support = true; | |
63 | ||
64 | static const char running_thread_name[] = "__gnat_running_thread_table"; | |
65 | ||
66 | static const char known_tasks_name[] = "system__tasking__debug__known_tasks"; | |
67 | static const char first_task_name[] = "system__tasking__debug__first_task"; | |
68 | ||
69 | static const char ravenscar_runtime_initializer[] | |
70 | = "system__bb__threads__initialize"; | |
71 | ||
72 | static const target_info ravenscar_target_info = { | |
73 | "ravenscar", | |
74 | N_("Ravenscar tasks."), | |
75 | N_("Ravenscar tasks support.") | |
76 | }; | |
77 | ||
78 | struct ravenscar_thread_target final : public target_ops | |
79 | { | |
80 | ravenscar_thread_target () | |
81 | : m_base_ptid (inferior_ptid) | |
82 | { | |
83 | } | |
84 | ||
85 | const target_info &info () const override | |
86 | { return ravenscar_target_info; } | |
87 | ||
88 | strata stratum () const override { return thread_stratum; } | |
89 | ||
90 | ptid_t wait (ptid_t, struct target_waitstatus *, target_wait_flags) override; | |
91 | void resume (ptid_t, int, enum gdb_signal) override; | |
92 | ||
93 | void fetch_registers (struct regcache *, int) override; | |
94 | void store_registers (struct regcache *, int) override; | |
95 | ||
96 | void prepare_to_store (struct regcache *) override; | |
97 | ||
98 | bool stopped_by_sw_breakpoint () override; | |
99 | ||
100 | bool stopped_by_hw_breakpoint () override; | |
101 | ||
102 | bool stopped_by_watchpoint () override; | |
103 | ||
104 | bool stopped_data_address (CORE_ADDR *) override; | |
105 | ||
106 | enum target_xfer_status xfer_partial (enum target_object object, | |
107 | const char *annex, | |
108 | gdb_byte *readbuf, | |
109 | const gdb_byte *writebuf, | |
110 | ULONGEST offset, ULONGEST len, | |
111 | ULONGEST *xfered_len) override; | |
112 | ||
113 | bool thread_alive (ptid_t ptid) override; | |
114 | ||
115 | int core_of_thread (ptid_t ptid) override; | |
116 | ||
117 | void update_thread_list () override; | |
118 | ||
119 | std::string pid_to_str (ptid_t) override; | |
120 | ||
121 | ptid_t get_ada_task_ptid (long lwp, ULONGEST thread) override; | |
122 | ||
123 | struct btrace_target_info *enable_btrace (thread_info *tp, | |
124 | const struct btrace_config *conf) | |
125 | override | |
126 | { | |
127 | process_stratum_target *proc_target | |
128 | = as_process_stratum_target (this->beneath ()); | |
129 | ptid_t underlying = get_base_thread_from_ravenscar_task (tp->ptid); | |
130 | tp = proc_target->find_thread (underlying); | |
131 | ||
132 | return beneath ()->enable_btrace (tp, conf); | |
133 | } | |
134 | ||
135 | void mourn_inferior () override; | |
136 | ||
137 | void close () override | |
138 | { | |
139 | delete this; | |
140 | } | |
141 | ||
142 | thread_info *add_active_thread (); | |
143 | ||
144 | private: | |
145 | ||
146 | /* PTID of the last thread that received an event. | |
147 | This can be useful to determine the associated task that received | |
148 | the event, to make it the current task. */ | |
149 | ptid_t m_base_ptid; | |
150 | ||
151 | ptid_t active_task (int cpu); | |
152 | bool task_is_currently_active (ptid_t ptid); | |
153 | bool runtime_initialized (); | |
154 | int get_thread_base_cpu (ptid_t ptid); | |
155 | ptid_t get_base_thread_from_ravenscar_task (ptid_t ptid); | |
156 | void add_thread (struct ada_task_info *task); | |
157 | ||
158 | /* Like switch_to_thread, but uses the base ptid for the thread. */ | |
159 | void set_base_thread_from_ravenscar_task (ptid_t ptid) | |
160 | { | |
161 | process_stratum_target *proc_target | |
162 | = as_process_stratum_target (this->beneath ()); | |
163 | ptid_t underlying = get_base_thread_from_ravenscar_task (ptid); | |
164 | switch_to_thread (proc_target->find_thread (underlying)); | |
165 | } | |
166 | ||
167 | /* Some targets use lazy FPU initialization. On these, the FP | |
168 | registers for a given task might be uninitialized, or stored in | |
169 | the per-task context, or simply be the live registers on the CPU. | |
170 | This enum is used to encode this information. */ | |
171 | enum fpu_state | |
172 | { | |
173 | /* This target doesn't do anything special for FP registers -- if | |
174 | any exist, they are treated just identical to non-FP | |
175 | registers. */ | |
176 | NOTHING_SPECIAL, | |
177 | /* This target uses the lazy FP scheme, and the FP registers are | |
178 | taken from the CPU. This can happen for any task, because if a | |
179 | task switch occurs, the registers aren't immediately written to | |
180 | the per-task context -- this is deferred until the current task | |
181 | causes an FPU trap. */ | |
182 | LIVE_FP_REGISTERS, | |
183 | /* This target uses the lazy FP scheme, and the FP registers are | |
184 | not available. Maybe this task never initialized the FPU, or | |
185 | maybe GDB couldn't find the required symbol. */ | |
186 | NO_FP_REGISTERS | |
187 | }; | |
188 | ||
189 | /* Return the FPU state. */ | |
190 | fpu_state get_fpu_state (struct regcache *regcache, | |
191 | const ravenscar_arch_ops *arch_ops); | |
192 | ||
193 | /* This maps a TID to the CPU on which it was running. This is | |
194 | needed because sometimes the runtime will report an active task | |
195 | that hasn't yet been put on the list of tasks that is read by | |
196 | ada-tasks.c. */ | |
197 | gdb::unordered_map<ULONGEST, int> m_cpu_map; | |
198 | }; | |
199 | ||
200 | /* Return true iff PTID corresponds to a ravenscar task. */ | |
201 | ||
202 | static bool | |
203 | is_ravenscar_task (ptid_t ptid) | |
204 | { | |
205 | /* By construction, ravenscar tasks have their LWP set to zero. | |
206 | Also make sure that the TID is nonzero, as some remotes, when | |
207 | asked for the list of threads, will return the first thread | |
208 | as having its TID set to zero. For instance, TSIM version | |
209 | 2.0.48 for LEON3 sends 'm0' as a reply to the 'qfThreadInfo' | |
210 | query, which the remote protocol layer then treats as a thread | |
211 | whose TID is 0. This is obviously not a ravenscar task. */ | |
212 | return ptid.lwp () == 0 && ptid.tid () != 0; | |
213 | } | |
214 | ||
215 | /* Given PTID, which can be either a ravenscar task or a CPU thread, | |
216 | return which CPU that ptid is running on. | |
217 | ||
218 | This assume that PTID is a valid ptid_t. Otherwise, a gdb_assert | |
219 | will be triggered. */ | |
220 | ||
221 | int | |
222 | ravenscar_thread_target::get_thread_base_cpu (ptid_t ptid) | |
223 | { | |
224 | int base_cpu; | |
225 | ||
226 | if (is_ravenscar_task (ptid)) | |
227 | { | |
228 | /* Prefer to not read inferior memory if possible, to avoid | |
229 | reentrancy problems with xfer_partial. */ | |
230 | auto iter = m_cpu_map.find (ptid.tid ()); | |
231 | ||
232 | if (iter != m_cpu_map.end ()) | |
233 | base_cpu = iter->second; | |
234 | else | |
235 | { | |
236 | struct ada_task_info *task_info = ada_get_task_info_from_ptid (ptid); | |
237 | ||
238 | gdb_assert (task_info != NULL); | |
239 | base_cpu = task_info->base_cpu; | |
240 | } | |
241 | } | |
242 | else | |
243 | { | |
244 | /* We assume that the LWP of the PTID is equal to the CPU number. */ | |
245 | base_cpu = ptid.lwp (); | |
246 | } | |
247 | ||
248 | return base_cpu; | |
249 | } | |
250 | ||
251 | /* Given a ravenscar task (identified by its ptid_t PTID), return true | |
252 | if this task is the currently active task on the cpu that task is | |
253 | running on. | |
254 | ||
255 | In other words, this function determine which CPU this task is | |
256 | currently running on, and then return nonzero if the CPU in question | |
257 | is executing the code for that task. If that's the case, then | |
258 | that task's registers are in the CPU bank. Otherwise, the task | |
259 | is currently suspended, and its registers have been saved in memory. */ | |
260 | ||
261 | bool | |
262 | ravenscar_thread_target::task_is_currently_active (ptid_t ptid) | |
263 | { | |
264 | ptid_t active_task_ptid = active_task (get_thread_base_cpu (ptid)); | |
265 | ||
266 | return ptid == active_task_ptid; | |
267 | } | |
268 | ||
269 | /* Return the CPU thread (as a ptid_t) on which the given ravenscar | |
270 | task is running. | |
271 | ||
272 | This is the thread that corresponds to the CPU on which the task | |
273 | is running. */ | |
274 | ||
275 | ptid_t | |
276 | ravenscar_thread_target::get_base_thread_from_ravenscar_task (ptid_t ptid) | |
277 | { | |
278 | int base_cpu; | |
279 | ||
280 | if (!is_ravenscar_task (ptid)) | |
281 | return ptid; | |
282 | ||
283 | base_cpu = get_thread_base_cpu (ptid); | |
284 | return ptid_t (ptid.pid (), base_cpu); | |
285 | } | |
286 | ||
287 | /* Fetch the ravenscar running thread from target memory, make sure | |
288 | there's a corresponding thread in the thread list, and return it. | |
289 | If the runtime is not initialized, return NULL. */ | |
290 | ||
291 | thread_info * | |
292 | ravenscar_thread_target::add_active_thread () | |
293 | { | |
294 | process_stratum_target *proc_target | |
295 | = as_process_stratum_target (this->beneath ()); | |
296 | ||
297 | int base_cpu; | |
298 | ||
299 | gdb_assert (!is_ravenscar_task (m_base_ptid)); | |
300 | base_cpu = get_thread_base_cpu (m_base_ptid); | |
301 | ||
302 | if (!runtime_initialized ()) | |
303 | return nullptr; | |
304 | ||
305 | /* It's possible for runtime_initialized to return true but for it | |
306 | not to be fully initialized. For example, this can happen for a | |
307 | breakpoint placed at the task's beginning. */ | |
308 | ptid_t active_ptid = active_task (base_cpu); | |
309 | if (active_ptid == null_ptid) | |
310 | return nullptr; | |
311 | ||
312 | /* The running thread may not have been added to | |
313 | system.tasking.debug's list yet; so ravenscar_update_thread_list | |
314 | may not always add it to the thread list. Add it here. */ | |
315 | thread_info *active_thr = proc_target->find_thread (active_ptid); | |
316 | if (active_thr == nullptr) | |
317 | { | |
318 | active_thr = ::add_thread (proc_target, active_ptid); | |
319 | m_cpu_map[active_ptid.tid ()] = base_cpu; | |
320 | } | |
321 | return active_thr; | |
322 | } | |
323 | ||
324 | /* The Ravenscar Runtime exports a symbol which contains the ID of | |
325 | the thread that is currently running. Try to locate that symbol | |
326 | and return its associated minimal symbol. | |
327 | Return NULL if not found. */ | |
328 | ||
329 | static bound_minimal_symbol | |
330 | get_running_thread_msymbol () | |
331 | { | |
332 | bound_minimal_symbol msym | |
333 | = lookup_minimal_symbol (current_program_space, running_thread_name); | |
334 | if (!msym.minsym) | |
335 | /* Older versions of the GNAT runtime were using a different | |
336 | (less ideal) name for the symbol where the active thread ID | |
337 | is stored. If we couldn't find the symbol using the latest | |
338 | name, then try the old one. */ | |
339 | msym = lookup_minimal_symbol (current_program_space, "running_thread"); | |
340 | ||
341 | return msym; | |
342 | } | |
343 | ||
344 | /* Return True if the Ada Ravenscar run-time can be found in the | |
345 | application. */ | |
346 | ||
347 | static bool | |
348 | has_ravenscar_runtime () | |
349 | { | |
350 | bound_minimal_symbol msym_ravenscar_runtime_initializer | |
351 | = lookup_minimal_symbol (current_program_space, | |
352 | ravenscar_runtime_initializer); | |
353 | bound_minimal_symbol msym_known_tasks | |
354 | = lookup_minimal_symbol (current_program_space, known_tasks_name); | |
355 | bound_minimal_symbol msym_first_task | |
356 | = lookup_minimal_symbol (current_program_space, first_task_name); | |
357 | bound_minimal_symbol msym_running_thread = get_running_thread_msymbol (); | |
358 | ||
359 | return (msym_ravenscar_runtime_initializer.minsym | |
360 | && (msym_known_tasks.minsym || msym_first_task.minsym) | |
361 | && msym_running_thread.minsym); | |
362 | } | |
363 | ||
364 | /* Return True if the Ada Ravenscar run-time can be found in the | |
365 | application, and if it has been initialized on target. */ | |
366 | ||
367 | bool | |
368 | ravenscar_thread_target::runtime_initialized () | |
369 | { | |
370 | return active_task (1) != null_ptid; | |
371 | } | |
372 | ||
373 | /* Return the ID of the thread that is currently running. | |
374 | Return 0 if the ID could not be determined. */ | |
375 | ||
376 | static CORE_ADDR | |
377 | get_running_thread_id (int cpu) | |
378 | { | |
379 | bound_minimal_symbol object_msym = get_running_thread_msymbol (); | |
380 | int object_size; | |
381 | int buf_size; | |
382 | gdb_byte *buf; | |
383 | CORE_ADDR object_addr; | |
384 | struct type *builtin_type_void_data_ptr | |
385 | = builtin_type (current_inferior ()->arch ())->builtin_data_ptr; | |
386 | ||
387 | if (!object_msym.minsym) | |
388 | return 0; | |
389 | ||
390 | object_size = builtin_type_void_data_ptr->length (); | |
391 | object_addr = (object_msym.value_address () | |
392 | + (cpu - 1) * object_size); | |
393 | buf_size = object_size; | |
394 | buf = (gdb_byte *) alloca (buf_size); | |
395 | read_memory (object_addr, buf, buf_size); | |
396 | return extract_typed_address (buf, builtin_type_void_data_ptr); | |
397 | } | |
398 | ||
399 | void | |
400 | ravenscar_thread_target::resume (ptid_t ptid, int step, | |
401 | enum gdb_signal siggnal) | |
402 | { | |
403 | /* If we see a wildcard resume, we simply pass that on. Otherwise, | |
404 | arrange to resume the base ptid. */ | |
405 | inferior_ptid = m_base_ptid; | |
406 | if (ptid.is_pid ()) | |
407 | { | |
408 | /* We only have one process, so resume all threads of it. */ | |
409 | ptid = minus_one_ptid; | |
410 | } | |
411 | else if (ptid != minus_one_ptid) | |
412 | ptid = m_base_ptid; | |
413 | beneath ()->resume (ptid, step, siggnal); | |
414 | } | |
415 | ||
416 | ptid_t | |
417 | ravenscar_thread_target::wait (ptid_t ptid, | |
418 | struct target_waitstatus *status, | |
419 | target_wait_flags options) | |
420 | { | |
421 | process_stratum_target *beneath | |
422 | = as_process_stratum_target (this->beneath ()); | |
423 | ptid_t event_ptid; | |
424 | ||
425 | if (ptid != minus_one_ptid) | |
426 | ptid = m_base_ptid; | |
427 | event_ptid = beneath->wait (ptid, status, 0); | |
428 | /* Find any new threads that might have been created, and return the | |
429 | active thread. | |
430 | ||
431 | Only do it if the program is still alive, though. Otherwise, | |
432 | this causes problems when debugging through the remote protocol, | |
433 | because we might try switching threads (and thus sending packets) | |
434 | after the remote has disconnected. */ | |
435 | if (status->kind () != TARGET_WAITKIND_EXITED | |
436 | && status->kind () != TARGET_WAITKIND_SIGNALLED | |
437 | && runtime_initialized ()) | |
438 | { | |
439 | m_base_ptid = event_ptid; | |
440 | this->update_thread_list (); | |
441 | thread_info *thr = this->add_active_thread (); | |
442 | if (thr != nullptr) | |
443 | return thr->ptid; | |
444 | } | |
445 | return event_ptid; | |
446 | } | |
447 | ||
448 | /* Add the thread associated to the given TASK to the thread list | |
449 | (if the thread has already been added, this is a no-op). */ | |
450 | ||
451 | void | |
452 | ravenscar_thread_target::add_thread (struct ada_task_info *task) | |
453 | { | |
454 | if (current_inferior ()->find_thread (task->ptid) == NULL) | |
455 | { | |
456 | ::add_thread (current_inferior ()->process_target (), task->ptid); | |
457 | m_cpu_map[task->ptid.tid ()] = task->base_cpu; | |
458 | } | |
459 | } | |
460 | ||
461 | void | |
462 | ravenscar_thread_target::update_thread_list () | |
463 | { | |
464 | /* iterate_over_live_ada_tasks requires that inferior_ptid be set, | |
465 | but this isn't always the case in target methods. So, we ensure | |
466 | it here. */ | |
467 | scoped_restore save_ptid = make_scoped_restore (&inferior_ptid, | |
468 | m_base_ptid); | |
469 | ||
470 | /* Do not clear the thread list before adding the Ada task, to keep | |
471 | the thread that the process stratum has included into it | |
472 | (m_base_ptid) and the running thread, that may not have been included | |
473 | to system.tasking.debug's list yet. */ | |
474 | ||
475 | iterate_over_live_ada_tasks ([this] (struct ada_task_info *task) | |
476 | { | |
477 | this->add_thread (task); | |
478 | }); | |
479 | } | |
480 | ||
481 | ptid_t | |
482 | ravenscar_thread_target::active_task (int cpu) | |
483 | { | |
484 | CORE_ADDR tid = get_running_thread_id (cpu); | |
485 | ||
486 | if (tid == 0) | |
487 | return null_ptid; | |
488 | else | |
489 | return ptid_t (m_base_ptid.pid (), 0, tid); | |
490 | } | |
491 | ||
492 | bool | |
493 | ravenscar_thread_target::thread_alive (ptid_t ptid) | |
494 | { | |
495 | /* Ravenscar tasks are non-terminating. */ | |
496 | return true; | |
497 | } | |
498 | ||
499 | std::string | |
500 | ravenscar_thread_target::pid_to_str (ptid_t ptid) | |
501 | { | |
502 | if (!is_ravenscar_task (ptid)) | |
503 | return beneath ()->pid_to_str (ptid); | |
504 | ||
505 | return string_printf ("Ravenscar Thread 0x%s", | |
506 | phex_nz (ptid.tid ())); | |
507 | } | |
508 | ||
509 | CORE_ADDR | |
510 | ravenscar_arch_ops::get_stack_base (struct regcache *regcache) const | |
511 | { | |
512 | struct gdbarch *gdbarch = regcache->arch (); | |
513 | const int sp_regnum = gdbarch_sp_regnum (gdbarch); | |
514 | ULONGEST stack_address; | |
515 | regcache_cooked_read_unsigned (regcache, sp_regnum, &stack_address); | |
516 | return (CORE_ADDR) stack_address; | |
517 | } | |
518 | ||
519 | void | |
520 | ravenscar_arch_ops::supply_one_register (struct regcache *regcache, | |
521 | int regnum, | |
522 | CORE_ADDR descriptor, | |
523 | CORE_ADDR stack_base) const | |
524 | { | |
525 | CORE_ADDR addr; | |
526 | if (regnum >= first_stack_register && regnum <= last_stack_register) | |
527 | addr = stack_base; | |
528 | else | |
529 | addr = descriptor; | |
530 | addr += offsets[regnum]; | |
531 | ||
532 | struct gdbarch *gdbarch = regcache->arch (); | |
533 | int size = register_size (gdbarch, regnum); | |
534 | gdb_byte *buf = (gdb_byte *) alloca (size); | |
535 | read_memory (addr, buf, size); | |
536 | regcache->raw_supply (regnum, buf); | |
537 | } | |
538 | ||
539 | void | |
540 | ravenscar_arch_ops::fetch_register (struct regcache *regcache, | |
541 | int regnum) const | |
542 | { | |
543 | gdb_assert (regnum != -1); | |
544 | ||
545 | struct gdbarch *gdbarch = regcache->arch (); | |
546 | /* The tid is the thread_id field, which is a pointer to the thread. */ | |
547 | CORE_ADDR thread_descriptor_address | |
548 | = (CORE_ADDR) regcache->ptid ().tid (); | |
549 | ||
550 | int sp_regno = -1; | |
551 | CORE_ADDR stack_address = 0; | |
552 | if (regnum >= first_stack_register && regnum <= last_stack_register) | |
553 | { | |
554 | /* We must supply SP for get_stack_base, so recurse. */ | |
555 | sp_regno = gdbarch_sp_regnum (gdbarch); | |
556 | gdb_assert (!(sp_regno >= first_stack_register | |
557 | && sp_regno <= last_stack_register)); | |
558 | fetch_register (regcache, sp_regno); | |
559 | stack_address = get_stack_base (regcache); | |
560 | } | |
561 | ||
562 | if (regnum < offsets.size () && offsets[regnum] != -1) | |
563 | supply_one_register (regcache, regnum, thread_descriptor_address, | |
564 | stack_address); | |
565 | } | |
566 | ||
567 | void | |
568 | ravenscar_arch_ops::store_one_register (struct regcache *regcache, int regnum, | |
569 | CORE_ADDR descriptor, | |
570 | CORE_ADDR stack_base) const | |
571 | { | |
572 | CORE_ADDR addr; | |
573 | if (regnum >= first_stack_register && regnum <= last_stack_register) | |
574 | addr = stack_base; | |
575 | else | |
576 | addr = descriptor; | |
577 | addr += offsets[regnum]; | |
578 | ||
579 | struct gdbarch *gdbarch = regcache->arch (); | |
580 | int size = register_size (gdbarch, regnum); | |
581 | gdb_byte *buf = (gdb_byte *) alloca (size); | |
582 | regcache->raw_collect (regnum, buf); | |
583 | write_memory (addr, buf, size); | |
584 | } | |
585 | ||
586 | void | |
587 | ravenscar_arch_ops::store_register (struct regcache *regcache, | |
588 | int regnum) const | |
589 | { | |
590 | gdb_assert (regnum != -1); | |
591 | ||
592 | /* The tid is the thread_id field, which is a pointer to the thread. */ | |
593 | CORE_ADDR thread_descriptor_address | |
594 | = (CORE_ADDR) regcache->ptid ().tid (); | |
595 | ||
596 | CORE_ADDR stack_address = 0; | |
597 | if (regnum >= first_stack_register && regnum <= last_stack_register) | |
598 | stack_address = get_stack_base (regcache); | |
599 | ||
600 | if (regnum < offsets.size () && offsets[regnum] != -1) | |
601 | store_one_register (regcache, regnum, thread_descriptor_address, | |
602 | stack_address); | |
603 | } | |
604 | ||
605 | /* Temporarily set the ptid of a regcache to some other value. When | |
606 | this object is destroyed, the regcache's original ptid is | |
607 | restored. */ | |
608 | ||
609 | class temporarily_change_regcache_ptid | |
610 | { | |
611 | public: | |
612 | ||
613 | temporarily_change_regcache_ptid (struct regcache *regcache, ptid_t new_ptid) | |
614 | : m_regcache (regcache), | |
615 | m_save_ptid (regcache->ptid ()) | |
616 | { | |
617 | m_regcache->set_ptid (new_ptid); | |
618 | } | |
619 | ||
620 | ~temporarily_change_regcache_ptid () | |
621 | { | |
622 | m_regcache->set_ptid (m_save_ptid); | |
623 | } | |
624 | ||
625 | private: | |
626 | ||
627 | /* The regcache. */ | |
628 | struct regcache *m_regcache; | |
629 | /* The saved ptid. */ | |
630 | ptid_t m_save_ptid; | |
631 | }; | |
632 | ||
633 | ravenscar_thread_target::fpu_state | |
634 | ravenscar_thread_target::get_fpu_state (struct regcache *regcache, | |
635 | const ravenscar_arch_ops *arch_ops) | |
636 | { | |
637 | /* We want to return true if the special FP register handling is | |
638 | needed. If this target doesn't have lazy FP, then no special | |
639 | treatment is ever needed. */ | |
640 | if (!arch_ops->on_demand_fp ()) | |
641 | return NOTHING_SPECIAL; | |
642 | ||
643 | bound_minimal_symbol fpu_context | |
644 | = lookup_minimal_symbol (current_program_space, | |
645 | "system__bb__cpu_primitives__current_fpu_context", | |
646 | nullptr, nullptr); | |
647 | /* If the symbol can't be found, just fall back. */ | |
648 | if (fpu_context.minsym == nullptr) | |
649 | return NO_FP_REGISTERS; | |
650 | ||
651 | type *ptr_type | |
652 | = builtin_type (current_inferior ()->arch ())->builtin_data_ptr; | |
653 | ptr_type = lookup_pointer_type (ptr_type); | |
654 | value *val = value_from_pointer (ptr_type, fpu_context.value_address ()); | |
655 | ||
656 | int cpu = get_thread_base_cpu (regcache->ptid ()); | |
657 | /* The array index type has a lower bound of 1 -- it is Ada code -- | |
658 | so subtract 1 here. */ | |
659 | val = value_ptradd (val, cpu - 1); | |
660 | ||
661 | val = value_ind (val); | |
662 | CORE_ADDR fpu_task = value_as_long (val); | |
663 | ||
664 | /* The tid is the thread_id field, which is a pointer to the thread. */ | |
665 | CORE_ADDR thread_descriptor_address | |
666 | = (CORE_ADDR) regcache->ptid ().tid (); | |
667 | if (fpu_task == (thread_descriptor_address | |
668 | + arch_ops->get_fpu_context_offset ())) | |
669 | return LIVE_FP_REGISTERS; | |
670 | ||
671 | int v_init_offset = arch_ops->get_v_init_offset (); | |
672 | gdb_byte init = 0; | |
673 | read_memory (thread_descriptor_address + v_init_offset, &init, 1); | |
674 | return init ? NOTHING_SPECIAL : NO_FP_REGISTERS; | |
675 | } | |
676 | ||
677 | void | |
678 | ravenscar_thread_target::fetch_registers (struct regcache *regcache, | |
679 | int regnum) | |
680 | { | |
681 | ptid_t ptid = regcache->ptid (); | |
682 | ||
683 | if (runtime_initialized () && is_ravenscar_task (ptid)) | |
684 | { | |
685 | struct gdbarch *gdbarch = regcache->arch (); | |
686 | bool is_active = task_is_currently_active (ptid); | |
687 | struct ravenscar_arch_ops *arch_ops = gdbarch_ravenscar_ops (gdbarch); | |
688 | std::optional<fpu_state> fp_state; | |
689 | ||
690 | int low_reg = regnum == -1 ? 0 : regnum; | |
691 | int high_reg = regnum == -1 ? gdbarch_num_regs (gdbarch) : regnum + 1; | |
692 | ||
693 | ptid_t base = get_base_thread_from_ravenscar_task (ptid); | |
694 | for (int i = low_reg; i < high_reg; ++i) | |
695 | { | |
696 | bool use_beneath = false; | |
697 | if (arch_ops->is_fp_register (i)) | |
698 | { | |
699 | if (!fp_state.has_value ()) | |
700 | fp_state = get_fpu_state (regcache, arch_ops); | |
701 | if (*fp_state == NO_FP_REGISTERS) | |
702 | continue; | |
703 | if (*fp_state == LIVE_FP_REGISTERS | |
704 | || (is_active && *fp_state == NOTHING_SPECIAL)) | |
705 | use_beneath = true; | |
706 | } | |
707 | else | |
708 | use_beneath = is_active; | |
709 | ||
710 | if (use_beneath) | |
711 | { | |
712 | temporarily_change_regcache_ptid changer (regcache, base); | |
713 | beneath ()->fetch_registers (regcache, i); | |
714 | } | |
715 | else | |
716 | arch_ops->fetch_register (regcache, i); | |
717 | } | |
718 | } | |
719 | else | |
720 | beneath ()->fetch_registers (regcache, regnum); | |
721 | } | |
722 | ||
723 | void | |
724 | ravenscar_thread_target::store_registers (struct regcache *regcache, | |
725 | int regnum) | |
726 | { | |
727 | ptid_t ptid = regcache->ptid (); | |
728 | ||
729 | if (runtime_initialized () && is_ravenscar_task (ptid)) | |
730 | { | |
731 | struct gdbarch *gdbarch = regcache->arch (); | |
732 | bool is_active = task_is_currently_active (ptid); | |
733 | struct ravenscar_arch_ops *arch_ops = gdbarch_ravenscar_ops (gdbarch); | |
734 | std::optional<fpu_state> fp_state; | |
735 | ||
736 | int low_reg = regnum == -1 ? 0 : regnum; | |
737 | int high_reg = regnum == -1 ? gdbarch_num_regs (gdbarch) : regnum + 1; | |
738 | ||
739 | ptid_t base = get_base_thread_from_ravenscar_task (ptid); | |
740 | for (int i = low_reg; i < high_reg; ++i) | |
741 | { | |
742 | bool use_beneath = false; | |
743 | if (arch_ops->is_fp_register (i)) | |
744 | { | |
745 | if (!fp_state.has_value ()) | |
746 | fp_state = get_fpu_state (regcache, arch_ops); | |
747 | if (*fp_state == NO_FP_REGISTERS) | |
748 | continue; | |
749 | if (*fp_state == LIVE_FP_REGISTERS | |
750 | || (is_active && *fp_state == NOTHING_SPECIAL)) | |
751 | use_beneath = true; | |
752 | } | |
753 | else | |
754 | use_beneath = is_active; | |
755 | ||
756 | if (use_beneath) | |
757 | { | |
758 | temporarily_change_regcache_ptid changer (regcache, base); | |
759 | beneath ()->store_registers (regcache, i); | |
760 | } | |
761 | else | |
762 | arch_ops->store_register (regcache, i); | |
763 | } | |
764 | } | |
765 | else | |
766 | beneath ()->store_registers (regcache, regnum); | |
767 | } | |
768 | ||
769 | void | |
770 | ravenscar_thread_target::prepare_to_store (struct regcache *regcache) | |
771 | { | |
772 | ptid_t ptid = regcache->ptid (); | |
773 | ||
774 | if (runtime_initialized () && is_ravenscar_task (ptid)) | |
775 | { | |
776 | if (task_is_currently_active (ptid)) | |
777 | { | |
778 | ptid_t base = get_base_thread_from_ravenscar_task (ptid); | |
779 | temporarily_change_regcache_ptid changer (regcache, base); | |
780 | beneath ()->prepare_to_store (regcache); | |
781 | } | |
782 | else | |
783 | { | |
784 | /* Nothing. */ | |
785 | } | |
786 | } | |
787 | else | |
788 | beneath ()->prepare_to_store (regcache); | |
789 | } | |
790 | ||
791 | /* Implement the to_stopped_by_sw_breakpoint target_ops "method". */ | |
792 | ||
793 | bool | |
794 | ravenscar_thread_target::stopped_by_sw_breakpoint () | |
795 | { | |
796 | scoped_restore_current_thread saver; | |
797 | set_base_thread_from_ravenscar_task (inferior_ptid); | |
798 | return beneath ()->stopped_by_sw_breakpoint (); | |
799 | } | |
800 | ||
801 | /* Implement the to_stopped_by_hw_breakpoint target_ops "method". */ | |
802 | ||
803 | bool | |
804 | ravenscar_thread_target::stopped_by_hw_breakpoint () | |
805 | { | |
806 | scoped_restore_current_thread saver; | |
807 | set_base_thread_from_ravenscar_task (inferior_ptid); | |
808 | return beneath ()->stopped_by_hw_breakpoint (); | |
809 | } | |
810 | ||
811 | /* Implement the to_stopped_by_watchpoint target_ops "method". */ | |
812 | ||
813 | bool | |
814 | ravenscar_thread_target::stopped_by_watchpoint () | |
815 | { | |
816 | scoped_restore_current_thread saver; | |
817 | set_base_thread_from_ravenscar_task (inferior_ptid); | |
818 | return beneath ()->stopped_by_watchpoint (); | |
819 | } | |
820 | ||
821 | /* Implement the to_stopped_data_address target_ops "method". */ | |
822 | ||
823 | bool | |
824 | ravenscar_thread_target::stopped_data_address (CORE_ADDR *addr_p) | |
825 | { | |
826 | scoped_restore_current_thread saver; | |
827 | set_base_thread_from_ravenscar_task (inferior_ptid); | |
828 | return beneath ()->stopped_data_address (addr_p); | |
829 | } | |
830 | ||
831 | void | |
832 | ravenscar_thread_target::mourn_inferior () | |
833 | { | |
834 | m_base_ptid = null_ptid; | |
835 | target_ops *beneath = this->beneath (); | |
836 | current_inferior ()->unpush_target (this); | |
837 | beneath->mourn_inferior (); | |
838 | } | |
839 | ||
840 | /* Implement the to_core_of_thread target_ops "method". */ | |
841 | ||
842 | int | |
843 | ravenscar_thread_target::core_of_thread (ptid_t ptid) | |
844 | { | |
845 | scoped_restore_current_thread saver; | |
846 | set_base_thread_from_ravenscar_task (inferior_ptid); | |
847 | return beneath ()->core_of_thread (inferior_ptid); | |
848 | } | |
849 | ||
850 | /* Implement the target xfer_partial method. */ | |
851 | ||
852 | enum target_xfer_status | |
853 | ravenscar_thread_target::xfer_partial (enum target_object object, | |
854 | const char *annex, | |
855 | gdb_byte *readbuf, | |
856 | const gdb_byte *writebuf, | |
857 | ULONGEST offset, ULONGEST len, | |
858 | ULONGEST *xfered_len) | |
859 | { | |
860 | scoped_restore save_ptid = make_scoped_restore (&inferior_ptid); | |
861 | /* Calling get_base_thread_from_ravenscar_task can read memory from | |
862 | the inferior. However, that function is written to prefer our | |
863 | internal map, so it should not result in recursive calls in | |
864 | practice. */ | |
865 | inferior_ptid = get_base_thread_from_ravenscar_task (inferior_ptid); | |
866 | return beneath ()->xfer_partial (object, annex, readbuf, writebuf, | |
867 | offset, len, xfered_len); | |
868 | } | |
869 | ||
870 | /* Observer on inferior_created: push ravenscar thread stratum if needed. */ | |
871 | ||
872 | static void | |
873 | ravenscar_inferior_created (inferior *inf) | |
874 | { | |
875 | const char *err_msg; | |
876 | ||
877 | if (!ravenscar_task_support | |
878 | || gdbarch_ravenscar_ops (current_inferior ()->arch ()) == NULL | |
879 | || !has_ravenscar_runtime ()) | |
880 | return; | |
881 | ||
882 | err_msg = ada_get_tcb_types_info (); | |
883 | if (err_msg != NULL) | |
884 | { | |
885 | warning (_("%s. Task/thread support disabled."), err_msg); | |
886 | return; | |
887 | } | |
888 | ||
889 | ravenscar_thread_target *rtarget = new ravenscar_thread_target (); | |
890 | inf->push_target (target_ops_up (rtarget)); | |
891 | thread_info *thr = rtarget->add_active_thread (); | |
892 | if (thr != nullptr) | |
893 | switch_to_thread (thr); | |
894 | } | |
895 | ||
896 | ptid_t | |
897 | ravenscar_thread_target::get_ada_task_ptid (long lwp, ULONGEST thread) | |
898 | { | |
899 | return ptid_t (m_base_ptid.pid (), 0, thread); | |
900 | } | |
901 | ||
902 | /* Command-list for the "set/show ravenscar" prefix command. */ | |
903 | static struct cmd_list_element *set_ravenscar_list; | |
904 | static struct cmd_list_element *show_ravenscar_list; | |
905 | ||
906 | /* Implement the "show ravenscar task-switching" command. */ | |
907 | ||
908 | static void | |
909 | show_ravenscar_task_switching_command (struct ui_file *file, int from_tty, | |
910 | struct cmd_list_element *c, | |
911 | const char *value) | |
912 | { | |
913 | if (ravenscar_task_support) | |
914 | gdb_printf (file, _("\ | |
915 | Support for Ravenscar task/thread switching is enabled\n")); | |
916 | else | |
917 | gdb_printf (file, _("\ | |
918 | Support for Ravenscar task/thread switching is disabled\n")); | |
919 | } | |
920 | ||
921 | /* Module startup initialization function, automagically called by | |
922 | init.c. */ | |
923 | ||
924 | INIT_GDB_FILE (ravenscar) | |
925 | { | |
926 | /* Notice when the inferior is created in order to push the | |
927 | ravenscar ops if needed. */ | |
928 | gdb::observers::inferior_created.attach (ravenscar_inferior_created, | |
929 | "ravenscar-thread"); | |
930 | ||
931 | add_setshow_prefix_cmd | |
932 | ("ravenscar", no_class, | |
933 | _("Prefix command for changing Ravenscar-specific settings."), | |
934 | _("Prefix command for showing Ravenscar-specific settings."), | |
935 | &set_ravenscar_list, &show_ravenscar_list, | |
936 | &setlist, &showlist); | |
937 | ||
938 | add_setshow_boolean_cmd ("task-switching", class_obscure, | |
939 | &ravenscar_task_support, _("\ | |
940 | Enable or disable support for GNAT Ravenscar tasks."), _("\ | |
941 | Show whether support for GNAT Ravenscar tasks is enabled."), | |
942 | _("\ | |
943 | Enable or disable support for task/thread switching with the GNAT\n\ | |
944 | Ravenscar run-time library for bareboard configuration."), | |
945 | NULL, show_ravenscar_task_switching_command, | |
946 | &set_ravenscar_list, &show_ravenscar_list); | |
947 | } |