xref: /linux/drivers/acpi/acpica/dswstate.c (revision 2fe05e1139a555ae91f00a812cb9520e7d3022ab)
1 /******************************************************************************
2  *
3  * Module Name: dswstate - Dispatcher parse tree walk management routines
4  *
5  *****************************************************************************/
6 
7 /*
8  * Copyright (C) 2000 - 2017, Intel Corp.
9  * All rights reserved.
10  *
11  * Redistribution and use in source and binary forms, with or without
12  * modification, are permitted provided that the following conditions
13  * are met:
14  * 1. Redistributions of source code must retain the above copyright
15  *    notice, this list of conditions, and the following disclaimer,
16  *    without modification.
17  * 2. Redistributions in binary form must reproduce at minimum a disclaimer
18  *    substantially similar to the "NO WARRANTY" disclaimer below
19  *    ("Disclaimer") and any redistribution must be conditioned upon
20  *    including a substantially similar Disclaimer requirement for further
21  *    binary redistribution.
22  * 3. Neither the names of the above-listed copyright holders nor the names
23  *    of any contributors may be used to endorse or promote products derived
24  *    from this software without specific prior written permission.
25  *
26  * Alternatively, this software may be distributed under the terms of the
27  * GNU General Public License ("GPL") version 2 as published by the Free
28  * Software Foundation.
29  *
30  * NO WARRANTY
31  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
32  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
33  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR
34  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
35  * HOLDERS OR CONTRIBUTORS BE LIABLE FOR SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
36  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
37  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
38  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
39  * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
40  * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
41  * POSSIBILITY OF SUCH DAMAGES.
42  */
43 
44 #include <acpi/acpi.h>
45 #include "accommon.h"
46 #include "acparser.h"
47 #include "acdispat.h"
48 #include "acnamesp.h"
49 
50 #define _COMPONENT          ACPI_DISPATCHER
51 ACPI_MODULE_NAME("dswstate")
52 
53   /* Local prototypes */
54 static acpi_status
55 acpi_ds_result_stack_push(struct acpi_walk_state *walk_state);
56 static acpi_status acpi_ds_result_stack_pop(struct acpi_walk_state *walk_state);
57 
58 /*******************************************************************************
59  *
60  * FUNCTION:    acpi_ds_result_pop
61  *
62  * PARAMETERS:  object              - Where to return the popped object
63  *              walk_state          - Current Walk state
64  *
65  * RETURN:      Status
66  *
67  * DESCRIPTION: Pop an object off the top of this walk's result stack
68  *
69  ******************************************************************************/
70 
71 acpi_status
72 acpi_ds_result_pop(union acpi_operand_object **object,
73 		   struct acpi_walk_state *walk_state)
74 {
75 	u32 index;
76 	union acpi_generic_state *state;
77 	acpi_status status;
78 
79 	ACPI_FUNCTION_NAME(ds_result_pop);
80 
81 	state = walk_state->results;
82 
83 	/* Incorrect state of result stack */
84 
85 	if (state && !walk_state->result_count) {
86 		ACPI_ERROR((AE_INFO, "No results on result stack"));
87 		return (AE_AML_INTERNAL);
88 	}
89 
90 	if (!state && walk_state->result_count) {
91 		ACPI_ERROR((AE_INFO, "No result state for result stack"));
92 		return (AE_AML_INTERNAL);
93 	}
94 
95 	/* Empty result stack */
96 
97 	if (!state) {
98 		ACPI_ERROR((AE_INFO, "Result stack is empty! State=%p",
99 			    walk_state));
100 		return (AE_AML_NO_RETURN_VALUE);
101 	}
102 
103 	/* Return object of the top element and clean that top element result stack */
104 
105 	walk_state->result_count--;
106 	index = (u32)walk_state->result_count % ACPI_RESULTS_FRAME_OBJ_NUM;
107 
108 	*object = state->results.obj_desc[index];
109 	if (!*object) {
110 		ACPI_ERROR((AE_INFO,
111 			    "No result objects on result stack, State=%p",
112 			    walk_state));
113 		return (AE_AML_NO_RETURN_VALUE);
114 	}
115 
116 	state->results.obj_desc[index] = NULL;
117 	if (index == 0) {
118 		status = acpi_ds_result_stack_pop(walk_state);
119 		if (ACPI_FAILURE(status)) {
120 			return (status);
121 		}
122 	}
123 
124 	ACPI_DEBUG_PRINT((ACPI_DB_EXEC,
125 			  "Obj=%p [%s] Index=%X State=%p Num=%X\n", *object,
126 			  acpi_ut_get_object_type_name(*object),
127 			  index, walk_state, walk_state->result_count));
128 
129 	return (AE_OK);
130 }
131 
132 /*******************************************************************************
133  *
134  * FUNCTION:    acpi_ds_result_push
135  *
136  * PARAMETERS:  object              - Where to return the popped object
137  *              walk_state          - Current Walk state
138  *
139  * RETURN:      Status
140  *
141  * DESCRIPTION: Push an object onto the current result stack
142  *
143  ******************************************************************************/
144 
145 acpi_status
146 acpi_ds_result_push(union acpi_operand_object *object,
147 		    struct acpi_walk_state *walk_state)
148 {
149 	union acpi_generic_state *state;
150 	acpi_status status;
151 	u32 index;
152 
153 	ACPI_FUNCTION_NAME(ds_result_push);
154 
155 	if (walk_state->result_count > walk_state->result_size) {
156 		ACPI_ERROR((AE_INFO, "Result stack is full"));
157 		return (AE_AML_INTERNAL);
158 	} else if (walk_state->result_count == walk_state->result_size) {
159 
160 		/* Extend the result stack */
161 
162 		status = acpi_ds_result_stack_push(walk_state);
163 		if (ACPI_FAILURE(status)) {
164 			ACPI_ERROR((AE_INFO,
165 				    "Failed to extend the result stack"));
166 			return (status);
167 		}
168 	}
169 
170 	if (!(walk_state->result_count < walk_state->result_size)) {
171 		ACPI_ERROR((AE_INFO, "No free elements in result stack"));
172 		return (AE_AML_INTERNAL);
173 	}
174 
175 	state = walk_state->results;
176 	if (!state) {
177 		ACPI_ERROR((AE_INFO, "No result stack frame during push"));
178 		return (AE_AML_INTERNAL);
179 	}
180 
181 	if (!object) {
182 		ACPI_ERROR((AE_INFO,
183 			    "Null Object! Obj=%p State=%p Num=%u",
184 			    object, walk_state, walk_state->result_count));
185 		return (AE_BAD_PARAMETER);
186 	}
187 
188 	/* Assign the address of object to the top free element of result stack */
189 
190 	index = (u32)walk_state->result_count % ACPI_RESULTS_FRAME_OBJ_NUM;
191 	state->results.obj_desc[index] = object;
192 	walk_state->result_count++;
193 
194 	ACPI_DEBUG_PRINT((ACPI_DB_EXEC, "Obj=%p [%s] State=%p Num=%X Cur=%X\n",
195 			  object,
196 			  acpi_ut_get_object_type_name((union
197 							acpi_operand_object *)
198 						       object), walk_state,
199 			  walk_state->result_count,
200 			  walk_state->current_result));
201 
202 	return (AE_OK);
203 }
204 
205 /*******************************************************************************
206  *
207  * FUNCTION:    acpi_ds_result_stack_push
208  *
209  * PARAMETERS:  walk_state          - Current Walk state
210  *
211  * RETURN:      Status
212  *
213  * DESCRIPTION: Push an object onto the walk_state result stack
214  *
215  ******************************************************************************/
216 
217 static acpi_status acpi_ds_result_stack_push(struct acpi_walk_state *walk_state)
218 {
219 	union acpi_generic_state *state;
220 
221 	ACPI_FUNCTION_NAME(ds_result_stack_push);
222 
223 	/* Check for stack overflow */
224 
225 	if (((u32) walk_state->result_size + ACPI_RESULTS_FRAME_OBJ_NUM) >
226 	    ACPI_RESULTS_OBJ_NUM_MAX) {
227 		ACPI_ERROR((AE_INFO, "Result stack overflow: State=%p Num=%u",
228 			    walk_state, walk_state->result_size));
229 		return (AE_STACK_OVERFLOW);
230 	}
231 
232 	state = acpi_ut_create_generic_state();
233 	if (!state) {
234 		return (AE_NO_MEMORY);
235 	}
236 
237 	state->common.descriptor_type = ACPI_DESC_TYPE_STATE_RESULT;
238 	acpi_ut_push_generic_state(&walk_state->results, state);
239 
240 	/* Increase the length of the result stack by the length of frame */
241 
242 	walk_state->result_size += ACPI_RESULTS_FRAME_OBJ_NUM;
243 
244 	ACPI_DEBUG_PRINT((ACPI_DB_EXEC, "Results=%p State=%p\n",
245 			  state, walk_state));
246 
247 	return (AE_OK);
248 }
249 
250 /*******************************************************************************
251  *
252  * FUNCTION:    acpi_ds_result_stack_pop
253  *
254  * PARAMETERS:  walk_state          - Current Walk state
255  *
256  * RETURN:      Status
257  *
258  * DESCRIPTION: Pop an object off of the walk_state result stack
259  *
260  ******************************************************************************/
261 
262 static acpi_status acpi_ds_result_stack_pop(struct acpi_walk_state *walk_state)
263 {
264 	union acpi_generic_state *state;
265 
266 	ACPI_FUNCTION_NAME(ds_result_stack_pop);
267 
268 	/* Check for stack underflow */
269 
270 	if (walk_state->results == NULL) {
271 		ACPI_DEBUG_PRINT((ACPI_DB_EXEC,
272 				  "Result stack underflow - State=%p\n",
273 				  walk_state));
274 		return (AE_AML_NO_OPERAND);
275 	}
276 
277 	if (walk_state->result_size < ACPI_RESULTS_FRAME_OBJ_NUM) {
278 		ACPI_ERROR((AE_INFO, "Insufficient result stack size"));
279 		return (AE_AML_INTERNAL);
280 	}
281 
282 	state = acpi_ut_pop_generic_state(&walk_state->results);
283 	acpi_ut_delete_generic_state(state);
284 
285 	/* Decrease the length of result stack by the length of frame */
286 
287 	walk_state->result_size -= ACPI_RESULTS_FRAME_OBJ_NUM;
288 
289 	ACPI_DEBUG_PRINT((ACPI_DB_EXEC,
290 			  "Result=%p RemainingResults=%X State=%p\n",
291 			  state, walk_state->result_count, walk_state));
292 
293 	return (AE_OK);
294 }
295 
296 /*******************************************************************************
297  *
298  * FUNCTION:    acpi_ds_obj_stack_push
299  *
300  * PARAMETERS:  object              - Object to push
301  *              walk_state          - Current Walk state
302  *
303  * RETURN:      Status
304  *
305  * DESCRIPTION: Push an object onto this walk's object/operand stack
306  *
307  ******************************************************************************/
308 
309 acpi_status
310 acpi_ds_obj_stack_push(void *object, struct acpi_walk_state *walk_state)
311 {
312 	ACPI_FUNCTION_NAME(ds_obj_stack_push);
313 
314 	/* Check for stack overflow */
315 
316 	if (walk_state->num_operands >= ACPI_OBJ_NUM_OPERANDS) {
317 		ACPI_ERROR((AE_INFO,
318 			    "Object stack overflow! Obj=%p State=%p #Ops=%u",
319 			    object, walk_state, walk_state->num_operands));
320 		return (AE_STACK_OVERFLOW);
321 	}
322 
323 	/* Put the object onto the stack */
324 
325 	walk_state->operands[walk_state->operand_index] = object;
326 	walk_state->num_operands++;
327 
328 	/* For the usual order of filling the operand stack */
329 
330 	walk_state->operand_index++;
331 
332 	ACPI_DEBUG_PRINT((ACPI_DB_EXEC, "Obj=%p [%s] State=%p #Ops=%X\n",
333 			  object,
334 			  acpi_ut_get_object_type_name((union
335 							acpi_operand_object *)
336 						       object), walk_state,
337 			  walk_state->num_operands));
338 
339 	return (AE_OK);
340 }
341 
342 /*******************************************************************************
343  *
344  * FUNCTION:    acpi_ds_obj_stack_pop
345  *
346  * PARAMETERS:  pop_count           - Number of objects/entries to pop
347  *              walk_state          - Current Walk state
348  *
349  * RETURN:      Status
350  *
351  * DESCRIPTION: Pop this walk's object stack. Objects on the stack are NOT
352  *              deleted by this routine.
353  *
354  ******************************************************************************/
355 
356 acpi_status
357 acpi_ds_obj_stack_pop(u32 pop_count, struct acpi_walk_state *walk_state)
358 {
359 	u32 i;
360 
361 	ACPI_FUNCTION_NAME(ds_obj_stack_pop);
362 
363 	for (i = 0; i < pop_count; i++) {
364 
365 		/* Check for stack underflow */
366 
367 		if (walk_state->num_operands == 0) {
368 			ACPI_ERROR((AE_INFO,
369 				    "Object stack underflow! Count=%X State=%p #Ops=%u",
370 				    pop_count, walk_state,
371 				    walk_state->num_operands));
372 			return (AE_STACK_UNDERFLOW);
373 		}
374 
375 		/* Just set the stack entry to null */
376 
377 		walk_state->num_operands--;
378 		walk_state->operands[walk_state->num_operands] = NULL;
379 	}
380 
381 	ACPI_DEBUG_PRINT((ACPI_DB_EXEC, "Count=%X State=%p #Ops=%u\n",
382 			  pop_count, walk_state, walk_state->num_operands));
383 
384 	return (AE_OK);
385 }
386 
387 /*******************************************************************************
388  *
389  * FUNCTION:    acpi_ds_obj_stack_pop_and_delete
390  *
391  * PARAMETERS:  pop_count           - Number of objects/entries to pop
392  *              walk_state          - Current Walk state
393  *
394  * RETURN:      Status
395  *
396  * DESCRIPTION: Pop this walk's object stack and delete each object that is
397  *              popped off.
398  *
399  ******************************************************************************/
400 
401 void
402 acpi_ds_obj_stack_pop_and_delete(u32 pop_count,
403 				 struct acpi_walk_state *walk_state)
404 {
405 	s32 i;
406 	union acpi_operand_object *obj_desc;
407 
408 	ACPI_FUNCTION_NAME(ds_obj_stack_pop_and_delete);
409 
410 	if (pop_count == 0) {
411 		return;
412 	}
413 
414 	for (i = (s32)pop_count - 1; i >= 0; i--) {
415 		if (walk_state->num_operands == 0) {
416 			return;
417 		}
418 
419 		/* Pop the stack and delete an object if present in this stack entry */
420 
421 		walk_state->num_operands--;
422 		obj_desc = walk_state->operands[i];
423 		if (obj_desc) {
424 			acpi_ut_remove_reference(walk_state->operands[i]);
425 			walk_state->operands[i] = NULL;
426 		}
427 	}
428 
429 	ACPI_DEBUG_PRINT((ACPI_DB_EXEC, "Count=%X State=%p #Ops=%X\n",
430 			  pop_count, walk_state, walk_state->num_operands));
431 }
432 
433 /*******************************************************************************
434  *
435  * FUNCTION:    acpi_ds_get_current_walk_state
436  *
437  * PARAMETERS:  thread          - Get current active state for this Thread
438  *
439  * RETURN:      Pointer to the current walk state
440  *
441  * DESCRIPTION: Get the walk state that is at the head of the list (the "current"
442  *              walk state.)
443  *
444  ******************************************************************************/
445 
446 struct acpi_walk_state *acpi_ds_get_current_walk_state(struct acpi_thread_state
447 						       *thread)
448 {
449 	ACPI_FUNCTION_NAME(ds_get_current_walk_state);
450 
451 	if (!thread) {
452 		return (NULL);
453 	}
454 
455 	ACPI_DEBUG_PRINT((ACPI_DB_PARSE, "Current WalkState %p\n",
456 			  thread->walk_state_list));
457 
458 	return (thread->walk_state_list);
459 }
460 
461 /*******************************************************************************
462  *
463  * FUNCTION:    acpi_ds_push_walk_state
464  *
465  * PARAMETERS:  walk_state      - State to push
466  *              thread          - Thread state object
467  *
468  * RETURN:      None
469  *
470  * DESCRIPTION: Place the Thread state at the head of the state list
471  *
472  ******************************************************************************/
473 
474 void
475 acpi_ds_push_walk_state(struct acpi_walk_state *walk_state,
476 			struct acpi_thread_state *thread)
477 {
478 	ACPI_FUNCTION_TRACE(ds_push_walk_state);
479 
480 	walk_state->next = thread->walk_state_list;
481 	thread->walk_state_list = walk_state;
482 
483 	return_VOID;
484 }
485 
486 /*******************************************************************************
487  *
488  * FUNCTION:    acpi_ds_pop_walk_state
489  *
490  * PARAMETERS:  thread      - Current thread state
491  *
492  * RETURN:      A walk_state object popped from the thread's stack
493  *
494  * DESCRIPTION: Remove and return the walkstate object that is at the head of
495  *              the walk stack for the given walk list. NULL indicates that
496  *              the list is empty.
497  *
498  ******************************************************************************/
499 
500 struct acpi_walk_state *acpi_ds_pop_walk_state(struct acpi_thread_state *thread)
501 {
502 	struct acpi_walk_state *walk_state;
503 
504 	ACPI_FUNCTION_TRACE(ds_pop_walk_state);
505 
506 	walk_state = thread->walk_state_list;
507 
508 	if (walk_state) {
509 
510 		/* Next walk state becomes the current walk state */
511 
512 		thread->walk_state_list = walk_state->next;
513 
514 		/*
515 		 * Don't clear the NEXT field, this serves as an indicator
516 		 * that there is a parent WALK STATE
517 		 * Do Not: walk_state->Next = NULL;
518 		 */
519 	}
520 
521 	return_PTR(walk_state);
522 }
523 
524 /*******************************************************************************
525  *
526  * FUNCTION:    acpi_ds_create_walk_state
527  *
528  * PARAMETERS:  owner_id        - ID for object creation
529  *              origin          - Starting point for this walk
530  *              method_desc     - Method object
531  *              thread          - Current thread state
532  *
533  * RETURN:      Pointer to the new walk state.
534  *
535  * DESCRIPTION: Allocate and initialize a new walk state. The current walk
536  *              state is set to this new state.
537  *
538  ******************************************************************************/
539 
540 struct acpi_walk_state *acpi_ds_create_walk_state(acpi_owner_id owner_id,
541 						  union acpi_parse_object
542 						  *origin,
543 						  union acpi_operand_object
544 						  *method_desc,
545 						  struct acpi_thread_state
546 						  *thread)
547 {
548 	struct acpi_walk_state *walk_state;
549 
550 	ACPI_FUNCTION_TRACE(ds_create_walk_state);
551 
552 	walk_state = ACPI_ALLOCATE_ZEROED(sizeof(struct acpi_walk_state));
553 	if (!walk_state) {
554 		return_PTR(NULL);
555 	}
556 
557 	walk_state->descriptor_type = ACPI_DESC_TYPE_WALK;
558 	walk_state->method_desc = method_desc;
559 	walk_state->owner_id = owner_id;
560 	walk_state->origin = origin;
561 	walk_state->thread = thread;
562 
563 	walk_state->parser_state.start_op = origin;
564 
565 	/* Init the method args/local */
566 
567 #if (!defined (ACPI_NO_METHOD_EXECUTION) && !defined (ACPI_CONSTANT_EVAL_ONLY))
568 	acpi_ds_method_data_init(walk_state);
569 #endif
570 
571 	/* Put the new state at the head of the walk list */
572 
573 	if (thread) {
574 		acpi_ds_push_walk_state(walk_state, thread);
575 	}
576 
577 	return_PTR(walk_state);
578 }
579 
580 /*******************************************************************************
581  *
582  * FUNCTION:    acpi_ds_init_aml_walk
583  *
584  * PARAMETERS:  walk_state      - New state to be initialized
585  *              op              - Current parse op
586  *              method_node     - Control method NS node, if any
587  *              aml_start       - Start of AML
588  *              aml_length      - Length of AML
589  *              info            - Method info block (params, etc.)
590  *              pass_number     - 1, 2, or 3
591  *
592  * RETURN:      Status
593  *
594  * DESCRIPTION: Initialize a walk state for a pass 1 or 2 parse tree walk
595  *
596  ******************************************************************************/
597 
598 acpi_status
599 acpi_ds_init_aml_walk(struct acpi_walk_state *walk_state,
600 		      union acpi_parse_object *op,
601 		      struct acpi_namespace_node *method_node,
602 		      u8 * aml_start,
603 		      u32 aml_length,
604 		      struct acpi_evaluate_info *info, u8 pass_number)
605 {
606 	acpi_status status;
607 	struct acpi_parse_state *parser_state = &walk_state->parser_state;
608 	union acpi_parse_object *extra_op;
609 
610 	ACPI_FUNCTION_TRACE(ds_init_aml_walk);
611 
612 	walk_state->parser_state.aml =
613 	    walk_state->parser_state.aml_start = aml_start;
614 	walk_state->parser_state.aml_end =
615 	    walk_state->parser_state.pkg_end = aml_start + aml_length;
616 
617 	/* The next_op of the next_walk will be the beginning of the method */
618 
619 	walk_state->next_op = NULL;
620 	walk_state->pass_number = pass_number;
621 
622 	if (info) {
623 		walk_state->params = info->parameters;
624 		walk_state->caller_return_desc = &info->return_object;
625 	}
626 
627 	status = acpi_ps_init_scope(&walk_state->parser_state, op);
628 	if (ACPI_FAILURE(status)) {
629 		return_ACPI_STATUS(status);
630 	}
631 
632 	if (method_node) {
633 		walk_state->parser_state.start_node = method_node;
634 		walk_state->walk_type = ACPI_WALK_METHOD;
635 		walk_state->method_node = method_node;
636 		walk_state->method_desc =
637 		    acpi_ns_get_attached_object(method_node);
638 
639 		/* Push start scope on scope stack and make it current  */
640 
641 		status =
642 		    acpi_ds_scope_stack_push(method_node, ACPI_TYPE_METHOD,
643 					     walk_state);
644 		if (ACPI_FAILURE(status)) {
645 			return_ACPI_STATUS(status);
646 		}
647 
648 		/* Init the method arguments */
649 
650 		status = acpi_ds_method_data_init_args(walk_state->params,
651 						       ACPI_METHOD_NUM_ARGS,
652 						       walk_state);
653 		if (ACPI_FAILURE(status)) {
654 			return_ACPI_STATUS(status);
655 		}
656 	} else {
657 		/*
658 		 * Setup the current scope.
659 		 * Find a Named Op that has a namespace node associated with it.
660 		 * search upwards from this Op. Current scope is the first
661 		 * Op with a namespace node.
662 		 */
663 		extra_op = parser_state->start_op;
664 		while (extra_op && !extra_op->common.node) {
665 			extra_op = extra_op->common.parent;
666 		}
667 
668 		if (!extra_op) {
669 			parser_state->start_node = NULL;
670 		} else {
671 			parser_state->start_node = extra_op->common.node;
672 		}
673 
674 		if (parser_state->start_node) {
675 
676 			/* Push start scope on scope stack and make it current  */
677 
678 			status =
679 			    acpi_ds_scope_stack_push(parser_state->start_node,
680 						     parser_state->start_node->
681 						     type, walk_state);
682 			if (ACPI_FAILURE(status)) {
683 				return_ACPI_STATUS(status);
684 			}
685 		}
686 	}
687 
688 	status = acpi_ds_init_callbacks(walk_state, pass_number);
689 	return_ACPI_STATUS(status);
690 }
691 
692 /*******************************************************************************
693  *
694  * FUNCTION:    acpi_ds_delete_walk_state
695  *
696  * PARAMETERS:  walk_state      - State to delete
697  *
698  * RETURN:      Status
699  *
700  * DESCRIPTION: Delete a walk state including all internal data structures
701  *
702  ******************************************************************************/
703 
704 void acpi_ds_delete_walk_state(struct acpi_walk_state *walk_state)
705 {
706 	union acpi_generic_state *state;
707 
708 	ACPI_FUNCTION_TRACE_PTR(ds_delete_walk_state, walk_state);
709 
710 	if (!walk_state) {
711 		return_VOID;
712 	}
713 
714 	if (walk_state->descriptor_type != ACPI_DESC_TYPE_WALK) {
715 		ACPI_ERROR((AE_INFO, "%p is not a valid walk state",
716 			    walk_state));
717 		return_VOID;
718 	}
719 
720 	/* There should not be any open scopes */
721 
722 	if (walk_state->parser_state.scope) {
723 		ACPI_ERROR((AE_INFO, "%p walk still has a scope list",
724 			    walk_state));
725 		acpi_ps_cleanup_scope(&walk_state->parser_state);
726 	}
727 
728 	/* Always must free any linked control states */
729 
730 	while (walk_state->control_state) {
731 		state = walk_state->control_state;
732 		walk_state->control_state = state->common.next;
733 
734 		acpi_ut_delete_generic_state(state);
735 	}
736 
737 	/* Always must free any linked parse states */
738 
739 	while (walk_state->scope_info) {
740 		state = walk_state->scope_info;
741 		walk_state->scope_info = state->common.next;
742 
743 		acpi_ut_delete_generic_state(state);
744 	}
745 
746 	/* Always must free any stacked result states */
747 
748 	while (walk_state->results) {
749 		state = walk_state->results;
750 		walk_state->results = state->common.next;
751 
752 		acpi_ut_delete_generic_state(state);
753 	}
754 
755 	ACPI_FREE(walk_state);
756 	return_VOID;
757 }
758