1 // SPDX-License-Identifier: BSD-3-Clause OR GPL-2.0
2 /******************************************************************************
3 *
4 * Module Name: dsmethod - Parser/Interpreter interface - control method parsing
5 *
6 * Copyright (C) 2000 - 2023, Intel Corp.
7 *
8 *****************************************************************************/
9
10 #include <acpi/acpi.h>
11 #include "accommon.h"
12 #include "acdispat.h"
13 #include "acinterp.h"
14 #include "acnamesp.h"
15 #include "acparser.h"
16 #include "amlcode.h"
17 #include "acdebug.h"
18
19 #define _COMPONENT ACPI_DISPATCHER
20 ACPI_MODULE_NAME("dsmethod")
21
22 /* Local prototypes */
23 static acpi_status
24 acpi_ds_detect_named_opcodes(struct acpi_walk_state *walk_state,
25 union acpi_parse_object **out_op);
26
27 static acpi_status
28 acpi_ds_create_method_mutex(union acpi_operand_object *method_desc);
29
30 /*******************************************************************************
31 *
32 * FUNCTION: acpi_ds_auto_serialize_method
33 *
34 * PARAMETERS: node - Namespace Node of the method
35 * obj_desc - Method object attached to node
36 *
37 * RETURN: Status
38 *
39 * DESCRIPTION: Parse a control method AML to scan for control methods that
40 * need serialization due to the creation of named objects.
41 *
42 * NOTE: It is a bit of overkill to mark all such methods serialized, since
43 * there is only a problem if the method actually blocks during execution.
44 * A blocking operation is, for example, a Sleep() operation, or any access
45 * to an operation region. However, it is probably not possible to easily
46 * detect whether a method will block or not, so we simply mark all suspicious
47 * methods as serialized.
48 *
49 * NOTE2: This code is essentially a generic routine for parsing a single
50 * control method.
51 *
52 ******************************************************************************/
53
54 acpi_status
acpi_ds_auto_serialize_method(struct acpi_namespace_node * node,union acpi_operand_object * obj_desc)55 acpi_ds_auto_serialize_method(struct acpi_namespace_node *node,
56 union acpi_operand_object *obj_desc)
57 {
58 acpi_status status;
59 union acpi_parse_object *op = NULL;
60 struct acpi_walk_state *walk_state;
61
62 ACPI_FUNCTION_TRACE_PTR(ds_auto_serialize_method, node);
63
64 ACPI_DEBUG_PRINT((ACPI_DB_PARSE,
65 "Method auto-serialization parse [%4.4s] %p\n",
66 acpi_ut_get_node_name(node), node));
67
68 /* Create/Init a root op for the method parse tree */
69
70 op = acpi_ps_alloc_op(AML_METHOD_OP, obj_desc->method.aml_start);
71 if (!op) {
72 return_ACPI_STATUS(AE_NO_MEMORY);
73 }
74
75 acpi_ps_set_name(op, node->name.integer);
76 op->common.node = node;
77
78 /* Create and initialize a new walk state */
79
80 walk_state =
81 acpi_ds_create_walk_state(node->owner_id, NULL, NULL, NULL);
82 if (!walk_state) {
83 acpi_ps_free_op(op);
84 return_ACPI_STATUS(AE_NO_MEMORY);
85 }
86
87 status = acpi_ds_init_aml_walk(walk_state, op, node,
88 obj_desc->method.aml_start,
89 obj_desc->method.aml_length, NULL, 0);
90 if (ACPI_FAILURE(status)) {
91 acpi_ds_delete_walk_state(walk_state);
92 acpi_ps_free_op(op);
93 return_ACPI_STATUS(status);
94 }
95
96 walk_state->descending_callback = acpi_ds_detect_named_opcodes;
97
98 /* Parse the method, scan for creation of named objects */
99
100 status = acpi_ps_parse_aml(walk_state);
101
102 acpi_ps_delete_parse_tree(op);
103 return_ACPI_STATUS(status);
104 }
105
106 /*******************************************************************************
107 *
108 * FUNCTION: acpi_ds_detect_named_opcodes
109 *
110 * PARAMETERS: walk_state - Current state of the parse tree walk
111 * out_op - Unused, required for parser interface
112 *
113 * RETURN: Status
114 *
115 * DESCRIPTION: Descending callback used during the loading of ACPI tables.
116 * Currently used to detect methods that must be marked serialized
117 * in order to avoid problems with the creation of named objects.
118 *
119 ******************************************************************************/
120
121 static acpi_status
acpi_ds_detect_named_opcodes(struct acpi_walk_state * walk_state,union acpi_parse_object ** out_op)122 acpi_ds_detect_named_opcodes(struct acpi_walk_state *walk_state,
123 union acpi_parse_object **out_op)
124 {
125
126 ACPI_FUNCTION_NAME(acpi_ds_detect_named_opcodes);
127
128 /* We are only interested in opcodes that create a new name */
129
130 if (!
131 (walk_state->op_info->
132 flags & (AML_NAMED | AML_CREATE | AML_FIELD))) {
133 return (AE_OK);
134 }
135
136 /*
137 * At this point, we know we have a Named object opcode.
138 * Mark the method as serialized. Later code will create a mutex for
139 * this method to enforce serialization.
140 *
141 * Note, ACPI_METHOD_IGNORE_SYNC_LEVEL flag means that we will ignore the
142 * Sync Level mechanism for this method, even though it is now serialized.
143 * Otherwise, there can be conflicts with existing ASL code that actually
144 * uses sync levels.
145 */
146 walk_state->method_desc->method.sync_level = 0;
147 walk_state->method_desc->method.info_flags |=
148 (ACPI_METHOD_SERIALIZED | ACPI_METHOD_IGNORE_SYNC_LEVEL);
149
150 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
151 "Method serialized [%4.4s] %p - [%s] (%4.4X)\n",
152 walk_state->method_node->name.ascii,
153 walk_state->method_node, walk_state->op_info->name,
154 walk_state->opcode));
155
156 /* Abort the parse, no need to examine this method any further */
157
158 return (AE_CTRL_TERMINATE);
159 }
160
161 /*******************************************************************************
162 *
163 * FUNCTION: acpi_ds_method_error
164 *
165 * PARAMETERS: status - Execution status
166 * walk_state - Current state
167 *
168 * RETURN: Status
169 *
170 * DESCRIPTION: Called on method error. Invoke the global exception handler if
171 * present, dump the method data if the debugger is configured
172 *
173 * Note: Allows the exception handler to change the status code
174 *
175 ******************************************************************************/
176
177 acpi_status
acpi_ds_method_error(acpi_status status,struct acpi_walk_state * walk_state)178 acpi_ds_method_error(acpi_status status, struct acpi_walk_state *walk_state)
179 {
180 u32 aml_offset;
181 acpi_name name = 0;
182
183 ACPI_FUNCTION_ENTRY();
184
185 /* Ignore AE_OK and control exception codes */
186
187 if (ACPI_SUCCESS(status) || (status & AE_CODE_CONTROL)) {
188 return (status);
189 }
190
191 /* Invoke the global exception handler */
192
193 if (acpi_gbl_exception_handler) {
194
195 /* Exit the interpreter, allow handler to execute methods */
196
197 acpi_ex_exit_interpreter();
198
199 /*
200 * Handler can map the exception code to anything it wants, including
201 * AE_OK, in which case the executing method will not be aborted.
202 */
203 aml_offset = (u32)ACPI_PTR_DIFF(walk_state->aml,
204 walk_state->parser_state.
205 aml_start);
206
207 if (walk_state->method_node) {
208 name = walk_state->method_node->name.integer;
209 } else if (walk_state->deferred_node) {
210 name = walk_state->deferred_node->name.integer;
211 }
212
213 status = acpi_gbl_exception_handler(status, name,
214 walk_state->opcode,
215 aml_offset, NULL);
216 acpi_ex_enter_interpreter();
217 }
218
219 acpi_ds_clear_implicit_return(walk_state);
220
221 if (ACPI_FAILURE(status)) {
222 acpi_ds_dump_method_stack(status, walk_state, walk_state->op);
223
224 /* Display method locals/args if debugger is present */
225
226 #ifdef ACPI_DEBUGGER
227 acpi_db_dump_method_info(status, walk_state);
228 #endif
229 }
230
231 return (status);
232 }
233
234 /*******************************************************************************
235 *
236 * FUNCTION: acpi_ds_create_method_mutex
237 *
238 * PARAMETERS: obj_desc - The method object
239 *
240 * RETURN: Status
241 *
242 * DESCRIPTION: Create a mutex object for a serialized control method
243 *
244 ******************************************************************************/
245
246 static acpi_status
acpi_ds_create_method_mutex(union acpi_operand_object * method_desc)247 acpi_ds_create_method_mutex(union acpi_operand_object *method_desc)
248 {
249 union acpi_operand_object *mutex_desc;
250 acpi_status status;
251
252 ACPI_FUNCTION_TRACE(ds_create_method_mutex);
253
254 /* Create the new mutex object */
255
256 mutex_desc = acpi_ut_create_internal_object(ACPI_TYPE_MUTEX);
257 if (!mutex_desc) {
258 return_ACPI_STATUS(AE_NO_MEMORY);
259 }
260
261 /* Create the actual OS Mutex */
262
263 status = acpi_os_create_mutex(&mutex_desc->mutex.os_mutex);
264 if (ACPI_FAILURE(status)) {
265 acpi_ut_delete_object_desc(mutex_desc);
266 return_ACPI_STATUS(status);
267 }
268
269 mutex_desc->mutex.sync_level = method_desc->method.sync_level;
270 method_desc->method.mutex = mutex_desc;
271 return_ACPI_STATUS(AE_OK);
272 }
273
274 /*******************************************************************************
275 *
276 * FUNCTION: acpi_ds_begin_method_execution
277 *
278 * PARAMETERS: method_node - Node of the method
279 * obj_desc - The method object
280 * walk_state - current state, NULL if not yet executing
281 * a method.
282 *
283 * RETURN: Status
284 *
285 * DESCRIPTION: Prepare a method for execution. Parses the method if necessary,
286 * increments the thread count, and waits at the method semaphore
287 * for clearance to execute.
288 *
289 ******************************************************************************/
290
291 acpi_status
acpi_ds_begin_method_execution(struct acpi_namespace_node * method_node,union acpi_operand_object * obj_desc,struct acpi_walk_state * walk_state)292 acpi_ds_begin_method_execution(struct acpi_namespace_node *method_node,
293 union acpi_operand_object *obj_desc,
294 struct acpi_walk_state *walk_state)
295 {
296 acpi_status status = AE_OK;
297
298 ACPI_FUNCTION_TRACE_PTR(ds_begin_method_execution, method_node);
299
300 if (!method_node) {
301 return_ACPI_STATUS(AE_NULL_ENTRY);
302 }
303
304 acpi_ex_start_trace_method(method_node, obj_desc, walk_state);
305
306 /* Prevent wraparound of thread count */
307
308 if (obj_desc->method.thread_count == ACPI_UINT8_MAX) {
309 ACPI_ERROR((AE_INFO,
310 "Method reached maximum reentrancy limit (255)"));
311 return_ACPI_STATUS(AE_AML_METHOD_LIMIT);
312 }
313
314 /*
315 * If this method is serialized, we need to acquire the method mutex.
316 */
317 if (obj_desc->method.info_flags & ACPI_METHOD_SERIALIZED) {
318 /*
319 * Create a mutex for the method if it is defined to be Serialized
320 * and a mutex has not already been created. We defer the mutex creation
321 * until a method is actually executed, to minimize the object count
322 */
323 if (!obj_desc->method.mutex) {
324 status = acpi_ds_create_method_mutex(obj_desc);
325 if (ACPI_FAILURE(status)) {
326 return_ACPI_STATUS(status);
327 }
328 }
329
330 /*
331 * The current_sync_level (per-thread) must be less than or equal to
332 * the sync level of the method. This mechanism provides some
333 * deadlock prevention.
334 *
335 * If the method was auto-serialized, we just ignore the sync level
336 * mechanism, because auto-serialization of methods can interfere
337 * with ASL code that actually uses sync levels.
338 *
339 * Top-level method invocation has no walk state at this point
340 */
341 if (walk_state &&
342 (!(obj_desc->method.
343 info_flags & ACPI_METHOD_IGNORE_SYNC_LEVEL))
344 && (walk_state->thread->current_sync_level >
345 obj_desc->method.mutex->mutex.sync_level)) {
346 ACPI_ERROR((AE_INFO,
347 "Cannot acquire Mutex for method [%4.4s]"
348 ", current SyncLevel is too large (%u)",
349 acpi_ut_get_node_name(method_node),
350 walk_state->thread->current_sync_level));
351
352 return_ACPI_STATUS(AE_AML_MUTEX_ORDER);
353 }
354
355 /*
356 * Obtain the method mutex if necessary. Do not acquire mutex for a
357 * recursive call.
358 */
359 if (!walk_state ||
360 !obj_desc->method.mutex->mutex.thread_id ||
361 (walk_state->thread->thread_id !=
362 obj_desc->method.mutex->mutex.thread_id)) {
363 /*
364 * Acquire the method mutex. This releases the interpreter if we
365 * block (and reacquires it before it returns)
366 */
367 status =
368 acpi_ex_system_wait_mutex(obj_desc->method.mutex->
369 mutex.os_mutex,
370 ACPI_WAIT_FOREVER);
371 if (ACPI_FAILURE(status)) {
372 return_ACPI_STATUS(status);
373 }
374
375 /* Update the mutex and walk info and save the original sync_level */
376
377 if (walk_state) {
378 obj_desc->method.mutex->mutex.
379 original_sync_level =
380 walk_state->thread->current_sync_level;
381
382 obj_desc->method.mutex->mutex.thread_id =
383 walk_state->thread->thread_id;
384
385 /*
386 * Update the current sync_level only if this is not an auto-
387 * serialized method. In the auto case, we have to ignore
388 * the sync level for the method mutex (created for the
389 * auto-serialization) because we have no idea of what the
390 * sync level should be. Therefore, just ignore it.
391 */
392 if (!(obj_desc->method.info_flags &
393 ACPI_METHOD_IGNORE_SYNC_LEVEL)) {
394 walk_state->thread->current_sync_level =
395 obj_desc->method.sync_level;
396 }
397 } else {
398 obj_desc->method.mutex->mutex.
399 original_sync_level =
400 obj_desc->method.mutex->mutex.sync_level;
401
402 obj_desc->method.mutex->mutex.thread_id =
403 acpi_os_get_thread_id();
404 }
405 }
406
407 /* Always increase acquisition depth */
408
409 obj_desc->method.mutex->mutex.acquisition_depth++;
410 }
411
412 /*
413 * Allocate an Owner ID for this method, only if this is the first thread
414 * to begin concurrent execution. We only need one owner_id, even if the
415 * method is invoked recursively.
416 */
417 if (!obj_desc->method.owner_id) {
418 status = acpi_ut_allocate_owner_id(&obj_desc->method.owner_id);
419 if (ACPI_FAILURE(status)) {
420 goto cleanup;
421 }
422 }
423
424 /*
425 * Increment the method parse tree thread count since it has been
426 * reentered one more time (even if it is the same thread)
427 */
428 obj_desc->method.thread_count++;
429 acpi_method_count++;
430 return_ACPI_STATUS(status);
431
432 cleanup:
433 /* On error, must release the method mutex (if present) */
434
435 if (obj_desc->method.mutex) {
436 acpi_os_release_mutex(obj_desc->method.mutex->mutex.os_mutex);
437 }
438 return_ACPI_STATUS(status);
439 }
440
441 /*******************************************************************************
442 *
443 * FUNCTION: acpi_ds_call_control_method
444 *
445 * PARAMETERS: thread - Info for this thread
446 * this_walk_state - Current walk state
447 * op - Current Op to be walked
448 *
449 * RETURN: Status
450 *
451 * DESCRIPTION: Transfer execution to a called control method
452 *
453 ******************************************************************************/
454
455 acpi_status
acpi_ds_call_control_method(struct acpi_thread_state * thread,struct acpi_walk_state * this_walk_state,union acpi_parse_object * op)456 acpi_ds_call_control_method(struct acpi_thread_state *thread,
457 struct acpi_walk_state *this_walk_state,
458 union acpi_parse_object *op)
459 {
460 acpi_status status;
461 struct acpi_namespace_node *method_node;
462 struct acpi_walk_state *next_walk_state = NULL;
463 union acpi_operand_object *obj_desc;
464 struct acpi_evaluate_info *info;
465 u32 i;
466
467 ACPI_FUNCTION_TRACE_PTR(ds_call_control_method, this_walk_state);
468
469 ACPI_DEBUG_PRINT((ACPI_DB_DISPATCH,
470 "Calling method %p, currentstate=%p\n",
471 this_walk_state->prev_op, this_walk_state));
472
473 /*
474 * Get the namespace entry for the control method we are about to call
475 */
476 method_node = this_walk_state->method_call_node;
477 if (!method_node) {
478 return_ACPI_STATUS(AE_NULL_ENTRY);
479 }
480
481 obj_desc = acpi_ns_get_attached_object(method_node);
482 if (!obj_desc) {
483 return_ACPI_STATUS(AE_NULL_OBJECT);
484 }
485
486 /* Init for new method, possibly wait on method mutex */
487
488 status =
489 acpi_ds_begin_method_execution(method_node, obj_desc,
490 this_walk_state);
491 if (ACPI_FAILURE(status)) {
492 return_ACPI_STATUS(status);
493 }
494
495 /* Begin method parse/execution. Create a new walk state */
496
497 next_walk_state =
498 acpi_ds_create_walk_state(obj_desc->method.owner_id, NULL, obj_desc,
499 thread);
500 if (!next_walk_state) {
501 status = AE_NO_MEMORY;
502 goto cleanup;
503 }
504
505 /*
506 * The resolved arguments were put on the previous walk state's operand
507 * stack. Operands on the previous walk state stack always
508 * start at index 0. Also, null terminate the list of arguments
509 */
510 this_walk_state->operands[this_walk_state->num_operands] = NULL;
511
512 /*
513 * Allocate and initialize the evaluation information block
514 * TBD: this is somewhat inefficient, should change interface to
515 * ds_init_aml_walk. For now, keeps this struct off the CPU stack
516 */
517 info = ACPI_ALLOCATE_ZEROED(sizeof(struct acpi_evaluate_info));
518 if (!info) {
519 status = AE_NO_MEMORY;
520 goto pop_walk_state;
521 }
522
523 info->parameters = &this_walk_state->operands[0];
524
525 status = acpi_ds_init_aml_walk(next_walk_state, NULL, method_node,
526 obj_desc->method.aml_start,
527 obj_desc->method.aml_length, info,
528 ACPI_IMODE_EXECUTE);
529
530 ACPI_FREE(info);
531 if (ACPI_FAILURE(status)) {
532 goto pop_walk_state;
533 }
534
535 next_walk_state->method_nesting_depth =
536 this_walk_state->method_nesting_depth + 1;
537
538 /*
539 * Delete the operands on the previous walkstate operand stack
540 * (they were copied to new objects)
541 */
542 for (i = 0; i < obj_desc->method.param_count; i++) {
543 acpi_ut_remove_reference(this_walk_state->operands[i]);
544 this_walk_state->operands[i] = NULL;
545 }
546
547 /* Clear the operand stack */
548
549 this_walk_state->num_operands = 0;
550
551 ACPI_DEBUG_PRINT((ACPI_DB_DISPATCH,
552 "**** Begin nested execution of [%4.4s] **** WalkState=%p\n",
553 method_node->name.ascii, next_walk_state));
554
555 this_walk_state->method_pathname =
556 acpi_ns_get_normalized_pathname(method_node, TRUE);
557 this_walk_state->method_is_nested = TRUE;
558
559 /* Optional object evaluation log */
560
561 ACPI_DEBUG_PRINT_RAW((ACPI_DB_EVALUATION,
562 "%-26s: %*s%s\n", " Nested method call",
563 next_walk_state->method_nesting_depth * 3, " ",
564 &this_walk_state->method_pathname[1]));
565
566 /* Invoke an internal method if necessary */
567
568 if (obj_desc->method.info_flags & ACPI_METHOD_INTERNAL_ONLY) {
569 status =
570 obj_desc->method.dispatch.implementation(next_walk_state);
571 if (status == AE_OK) {
572 status = AE_CTRL_TERMINATE;
573 }
574 }
575
576 return_ACPI_STATUS(status);
577
578 pop_walk_state:
579
580 /* On error, pop the walk state to be deleted from thread */
581
582 acpi_ds_pop_walk_state(thread);
583
584 cleanup:
585
586 /* On error, we must terminate the method properly */
587
588 acpi_ds_terminate_control_method(obj_desc, next_walk_state);
589 acpi_ds_delete_walk_state(next_walk_state);
590
591 return_ACPI_STATUS(status);
592 }
593
594 /*******************************************************************************
595 *
596 * FUNCTION: acpi_ds_restart_control_method
597 *
598 * PARAMETERS: walk_state - State for preempted method (caller)
599 * return_desc - Return value from the called method
600 *
601 * RETURN: Status
602 *
603 * DESCRIPTION: Restart a method that was preempted by another (nested) method
604 * invocation. Handle the return value (if any) from the callee.
605 *
606 ******************************************************************************/
607
608 acpi_status
acpi_ds_restart_control_method(struct acpi_walk_state * walk_state,union acpi_operand_object * return_desc)609 acpi_ds_restart_control_method(struct acpi_walk_state *walk_state,
610 union acpi_operand_object *return_desc)
611 {
612 acpi_status status;
613 int same_as_implicit_return;
614
615 ACPI_FUNCTION_TRACE_PTR(ds_restart_control_method, walk_state);
616
617 ACPI_DEBUG_PRINT((ACPI_DB_DISPATCH,
618 "****Restart [%4.4s] Op %p ReturnValueFromCallee %p\n",
619 acpi_ut_get_node_name(walk_state->method_node),
620 walk_state->method_call_op, return_desc));
621
622 ACPI_DEBUG_PRINT((ACPI_DB_DISPATCH,
623 " ReturnFromThisMethodUsed?=%X ResStack %p Walk %p\n",
624 walk_state->return_used,
625 walk_state->results, walk_state));
626
627 /* Did the called method return a value? */
628
629 if (return_desc) {
630
631 /* Is the implicit return object the same as the return desc? */
632
633 same_as_implicit_return =
634 (walk_state->implicit_return_obj == return_desc);
635
636 /* Are we actually going to use the return value? */
637
638 if (walk_state->return_used) {
639
640 /* Save the return value from the previous method */
641
642 status = acpi_ds_result_push(return_desc, walk_state);
643 if (ACPI_FAILURE(status)) {
644 acpi_ut_remove_reference(return_desc);
645 return_ACPI_STATUS(status);
646 }
647
648 /*
649 * Save as THIS method's return value in case it is returned
650 * immediately to yet another method
651 */
652 walk_state->return_desc = return_desc;
653 }
654
655 /*
656 * The following code is the optional support for the so-called
657 * "implicit return". Some AML code assumes that the last value of the
658 * method is "implicitly" returned to the caller, in the absence of an
659 * explicit return value.
660 *
661 * Just save the last result of the method as the return value.
662 *
663 * NOTE: this is optional because the ASL language does not actually
664 * support this behavior.
665 */
666 else if (!acpi_ds_do_implicit_return
667 (return_desc, walk_state, FALSE)
668 || same_as_implicit_return) {
669 /*
670 * Delete the return value if it will not be used by the
671 * calling method or remove one reference if the explicit return
672 * is the same as the implicit return value.
673 */
674 acpi_ut_remove_reference(return_desc);
675 }
676 }
677
678 return_ACPI_STATUS(AE_OK);
679 }
680
681 /*******************************************************************************
682 *
683 * FUNCTION: acpi_ds_terminate_control_method
684 *
685 * PARAMETERS: method_desc - Method object
686 * walk_state - State associated with the method
687 *
688 * RETURN: None
689 *
690 * DESCRIPTION: Terminate a control method. Delete everything that the method
691 * created, delete all locals and arguments, and delete the parse
692 * tree if requested.
693 *
694 * MUTEX: Interpreter is locked
695 *
696 ******************************************************************************/
697
698 void
acpi_ds_terminate_control_method(union acpi_operand_object * method_desc,struct acpi_walk_state * walk_state)699 acpi_ds_terminate_control_method(union acpi_operand_object *method_desc,
700 struct acpi_walk_state *walk_state)
701 {
702
703 ACPI_FUNCTION_TRACE_PTR(ds_terminate_control_method, walk_state);
704
705 /* method_desc is required, walk_state is optional */
706
707 if (!method_desc) {
708 return_VOID;
709 }
710
711 if (walk_state) {
712
713 /* Delete all arguments and locals */
714
715 acpi_ds_method_data_delete_all(walk_state);
716
717 /*
718 * Delete any namespace objects created anywhere within the
719 * namespace by the execution of this method. Unless:
720 * 1) This method is a module-level executable code method, in which
721 * case we want make the objects permanent.
722 * 2) There are other threads executing the method, in which case we
723 * will wait until the last thread has completed.
724 */
725 if (!(method_desc->method.info_flags & ACPI_METHOD_MODULE_LEVEL)
726 && (method_desc->method.thread_count == 1)) {
727
728 /* Delete any direct children of (created by) this method */
729
730 (void)acpi_ex_exit_interpreter();
731 acpi_ns_delete_namespace_subtree(walk_state->
732 method_node);
733 (void)acpi_ex_enter_interpreter();
734
735 /*
736 * Delete any objects that were created by this method
737 * elsewhere in the namespace (if any were created).
738 * Use of the ACPI_METHOD_MODIFIED_NAMESPACE optimizes the
739 * deletion such that we don't have to perform an entire
740 * namespace walk for every control method execution.
741 */
742 if (method_desc->method.
743 info_flags & ACPI_METHOD_MODIFIED_NAMESPACE) {
744 (void)acpi_ex_exit_interpreter();
745 acpi_ns_delete_namespace_by_owner(method_desc->
746 method.
747 owner_id);
748 (void)acpi_ex_enter_interpreter();
749 method_desc->method.info_flags &=
750 ~ACPI_METHOD_MODIFIED_NAMESPACE;
751 }
752 }
753
754 /*
755 * If method is serialized, release the mutex and restore the
756 * current sync level for this thread
757 */
758 if (method_desc->method.mutex) {
759
760 /* Acquisition Depth handles recursive calls */
761
762 method_desc->method.mutex->mutex.acquisition_depth--;
763 if (!method_desc->method.mutex->mutex.acquisition_depth) {
764 walk_state->thread->current_sync_level =
765 method_desc->method.mutex->mutex.
766 original_sync_level;
767
768 acpi_os_release_mutex(method_desc->method.
769 mutex->mutex.os_mutex);
770 method_desc->method.mutex->mutex.thread_id = 0;
771 }
772 }
773 }
774
775 /* Decrement the thread count on the method */
776
777 if (method_desc->method.thread_count) {
778 method_desc->method.thread_count--;
779 } else {
780 ACPI_ERROR((AE_INFO, "Invalid zero thread count in method"));
781 }
782
783 /* Are there any other threads currently executing this method? */
784
785 if (method_desc->method.thread_count) {
786 /*
787 * Additional threads. Do not release the owner_id in this case,
788 * we immediately reuse it for the next thread executing this method
789 */
790 ACPI_DEBUG_PRINT((ACPI_DB_DISPATCH,
791 "*** Completed execution of one thread, %u threads remaining\n",
792 method_desc->method.thread_count));
793 } else {
794 /* This is the only executing thread for this method */
795
796 /*
797 * Support to dynamically change a method from not_serialized to
798 * Serialized if it appears that the method is incorrectly written and
799 * does not support multiple thread execution. The best example of this
800 * is if such a method creates namespace objects and blocks. A second
801 * thread will fail with an AE_ALREADY_EXISTS exception.
802 *
803 * This code is here because we must wait until the last thread exits
804 * before marking the method as serialized.
805 */
806 if (method_desc->method.
807 info_flags & ACPI_METHOD_SERIALIZED_PENDING) {
808 if (walk_state) {
809 ACPI_INFO(("Marking method %4.4s as Serialized "
810 "because of AE_ALREADY_EXISTS error",
811 walk_state->method_node->name.
812 ascii));
813 }
814
815 /*
816 * Method tried to create an object twice and was marked as
817 * "pending serialized". The probable cause is that the method
818 * cannot handle reentrancy.
819 *
820 * The method was created as not_serialized, but it tried to create
821 * a named object and then blocked, causing the second thread
822 * entrance to begin and then fail. Workaround this problem by
823 * marking the method permanently as Serialized when the last
824 * thread exits here.
825 */
826 method_desc->method.info_flags &=
827 ~ACPI_METHOD_SERIALIZED_PENDING;
828
829 method_desc->method.info_flags |=
830 (ACPI_METHOD_SERIALIZED |
831 ACPI_METHOD_IGNORE_SYNC_LEVEL);
832 method_desc->method.sync_level = 0;
833 }
834
835 /* No more threads, we can free the owner_id */
836
837 if (!
838 (method_desc->method.
839 info_flags & ACPI_METHOD_MODULE_LEVEL)) {
840 acpi_ut_release_owner_id(&method_desc->method.owner_id);
841 }
842 }
843
844 acpi_ex_stop_trace_method((struct acpi_namespace_node *)method_desc->
845 method.node, method_desc, walk_state);
846
847 return_VOID;
848 }
849