summaryrefslogtreecommitdiffstats
path: root/drivers/acpi/acpica/dswstate.c
blob: 3a26ddbaed6d64502f15405c09867c56d78ff434 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
/******************************************************************************
 *
 * Module Name: dswstate - Dispatcher parse tree walk management routines
 *
 *****************************************************************************/

/*
 * Copyright (C) 2000 - 2016, Intel Corp.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions, and the following disclaimer,
 *    without modification.
 * 2. Redistributions in binary form must reproduce at minimum a disclaimer
 *    substantially similar to the "NO WARRANTY" disclaimer below
 *    ("Disclaimer") and any redistribution must be conditioned upon
 *    including a substantially similar Disclaimer requirement for further
 *    binary redistribution.
 * 3. Neither the names of the above-listed copyright holders nor the names
 *    of any contributors may be used to endorse or promote products derived
 *    from this software without specific prior written permission.
 *
 * Alternatively, this software may be distributed under the terms of the
 * GNU General Public License ("GPL") version 2 as published by the Free
 * Software Foundation.
 *
 * NO WARRANTY
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * HOLDERS OR CONTRIBUTORS BE LIABLE FOR SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
 * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGES.
 */

#include <acpi/acpi.h>
#include "accommon.h"
#include "acparser.h"
#include "acdispat.h"
#include "acnamesp.h"

#define _COMPONENT          ACPI_DISPATCHER
ACPI_MODULE_NAME("dswstate")

  /* Local prototypes */
static acpi_status
acpi_ds_result_stack_push(struct acpi_walk_state *walk_state);
static acpi_status acpi_ds_result_stack_pop(struct acpi_walk_state *walk_state);

/*******************************************************************************
 *
 * FUNCTION:    acpi_ds_result_pop
 *
 * PARAMETERS:  object              - Where to return the popped object
 *              walk_state          - Current Walk state
 *
 * RETURN:      Status
 *
 * DESCRIPTION: Pop an object off the top of this walk's result stack
 *
 ******************************************************************************/

acpi_status
acpi_ds_result_pop(union acpi_operand_object **object,
		   struct acpi_walk_state *walk_state)
{
	u32 index;
	union acpi_generic_state *state;
	acpi_status status;

	ACPI_FUNCTION_NAME(ds_result_pop);

	state = walk_state->results;

	/* Incorrect state of result stack */

	if (state && !walk_state->result_count) {
		ACPI_ERROR((AE_INFO, "No results on result stack"));
		return (AE_AML_INTERNAL);
	}

	if (!state && walk_state->result_count) {
		ACPI_ERROR((AE_INFO, "No result state for result stack"));
		return (AE_AML_INTERNAL);
	}

	/* Empty result stack */

	if (!state) {
		ACPI_ERROR((AE_INFO, "Result stack is empty! State=%p",
			    walk_state));
		return (AE_AML_NO_RETURN_VALUE);
	}

	/* Return object of the top element and clean that top element result stack */

	walk_state->result_count--;
	index = (u32)walk_state->result_count % ACPI_RESULTS_FRAME_OBJ_NUM;

	*object = state->results.obj_desc[index];
	if (!*object) {
		ACPI_ERROR((AE_INFO,
			    "No result objects on result stack, State=%p",
			    walk_state));
		return (AE_AML_NO_RETURN_VALUE);
	}

	state->results.obj_desc[index] = NULL;
	if (index == 0) {
		status = acpi_ds_result_stack_pop(walk_state);
		if (ACPI_FAILURE(status)) {
			return (status);
		}
	}

	ACPI_DEBUG_PRINT((ACPI_DB_EXEC,
			  "Obj=%p [%s] Index=%X State=%p Num=%X\n", *object,
			  acpi_ut_get_object_type_name(*object),
			  index, walk_state, walk_state->result_count));

	return (AE_OK);
}

/*******************************************************************************
 *
 * FUNCTION:    acpi_ds_result_push
 *
 * PARAMETERS:  object              - Where to return the popped object
 *              walk_state          - Current Walk state
 *
 * RETURN:      Status
 *
 * DESCRIPTION: Push an object onto the current result stack
 *
 ******************************************************************************/

acpi_status
acpi_ds_result_push(union acpi_operand_object * object,
		    struct acpi_walk_state * walk_state)
{
	union acpi_generic_state *state;
	acpi_status status;
	u32 index;

	ACPI_FUNCTION_NAME(ds_result_push);

	if (walk_state->result_count > walk_state->result_size) {
		ACPI_ERROR((AE_INFO, "Result stack is full"));
		return (AE_AML_INTERNAL);
	} else if (walk_state->result_count == walk_state->result_size) {

		/* Extend the result stack */

		status = acpi_ds_result_stack_push(walk_state);
		if (ACPI_FAILURE(status)) {
			ACPI_ERROR((AE_INFO,
				    "Failed to extend the result stack"));
			return (status);
		}
	}

	if (!(walk_state->result_count < walk_state->result_size)) {
		ACPI_ERROR((AE_INFO, "No free elements in result stack"));
		return (AE_AML_INTERNAL);
	}

	state = walk_state->results;
	if (!state) {
		ACPI_ERROR((AE_INFO, "No result stack frame during push"));
		return (AE_AML_INTERNAL);
	}

	if (!object) {
		ACPI_ERROR((AE_INFO,
			    "Null Object! Obj=%p State=%p Num=%u",
			    object, walk_state, walk_state->result_count));
		return (AE_BAD_PARAMETER);
	}

	/* Assign the address of object to the top free element of result stack */

	index = (u32)walk_state->result_count % ACPI_RESULTS_FRAME_OBJ_NUM;
	state->results.obj_desc[index] = object;
	walk_state->result_count++;

	ACPI_DEBUG_PRINT((ACPI_DB_EXEC, "Obj=%p [%s] State=%p Num=%X Cur=%X\n",
			  object,
			  acpi_ut_get_object_type_name((union
							acpi_operand_object *)
						       object), walk_state,
			  walk_state->result_count,
			  walk_state->current_result));

	return (AE_OK);
}

/*******************************************************************************
 *
 * FUNCTION:    acpi_ds_result_stack_push
 *
 * PARAMETERS:  walk_state          - Current Walk state
 *
 * RETURN:      Status
 *
 * DESCRIPTION: Push an object onto the walk_state result stack
 *
 ******************************************************************************/

static acpi_status acpi_ds_result_stack_push(struct acpi_walk_state *walk_state)
{
	union acpi_generic_state *state;

	ACPI_FUNCTION_NAME(ds_result_stack_push);

	/* Check for stack overflow */

	if (((u32) walk_state->result_size + ACPI_RESULTS_FRAME_OBJ_NUM) >
	    ACPI_RESULTS_OBJ_NUM_MAX) {
		ACPI_ERROR((AE_INFO, "Result stack overflow: State=%p Num=%u",
			    walk_state, walk_state->result_size));
		return (AE_STACK_OVERFLOW);
	}

	state = acpi_ut_create_generic_state();
	if (!state) {
		return (AE_NO_MEMORY);
	}

	state->common.descriptor_type = ACPI_DESC_TYPE_STATE_RESULT;
	acpi_ut_push_generic_state(&walk_state->results, state);

	/* Increase the length of the result stack by the length of frame */

	walk_state->result_size += ACPI_RESULTS_FRAME_OBJ_NUM;

	ACPI_DEBUG_PRINT((ACPI_DB_EXEC, "Results=%p State=%p\n",
			  state, walk_state));

	return (AE_OK);
}

/*******************************************************************************
 *
 * FUNCTION:    acpi_ds_result_stack_pop
 *
 * PARAMETERS:  walk_state          - Current Walk state
 *
 * RETURN:      Status
 *
 * DESCRIPTION: Pop an object off of the walk_state result stack
 *
 ******************************************************************************/

static acpi_status acpi_ds_result_stack_pop(struct acpi_walk_state *walk_state)
{
	union acpi_generic_state *state;

	ACPI_FUNCTION_NAME(ds_result_stack_pop);

	/* Check for stack underflow */

	if (walk_state->results == NULL) {
		ACPI_DEBUG_PRINT((ACPI_DB_EXEC,
				  "Result stack underflow - State=%p\n",
				  walk_state));
		return (AE_AML_NO_OPERAND);
	}

	if (walk_state->result_size < ACPI_RESULTS_FRAME_OBJ_NUM) {
		ACPI_ERROR((AE_INFO, "Insufficient result stack size"));
		return (AE_AML_INTERNAL);
	}

	state = acpi_ut_pop_generic_state(&walk_state->results);
	acpi_ut_delete_generic_state(state);

	/* Decrease the length of result stack by the length of frame */

	walk_state->result_size -= ACPI_RESULTS_FRAME_OBJ_NUM;

	ACPI_DEBUG_PRINT((ACPI_DB_EXEC,
			  "Result=%p RemainingResults=%X State=%p\n",
			  state, walk_state->result_count, walk_state));

	return (AE_OK);
}

/*******************************************************************************
 *
 * FUNCTION:    acpi_ds_obj_stack_push
 *
 * PARAMETERS:  object              - Object to push
 *              walk_state          - Current Walk state
 *
 * RETURN:      Status
 *
 * DESCRIPTION: Push an object onto this walk's object/operand stack
 *
 ******************************************************************************/

acpi_status
acpi_ds_obj_stack_push(void *object, struct acpi_walk_state * walk_state)
{
	ACPI_FUNCTION_NAME(ds_obj_stack_push);

	/* Check for stack overflow */

	if (walk_state->num_operands >= ACPI_OBJ_NUM_OPERANDS) {
		ACPI_ERROR((AE_INFO,
			    "Object stack overflow! Obj=%p State=%p #Ops=%u",
			    object, walk_state, walk_state->num_operands));
		return (AE_STACK_OVERFLOW);
	}

	/* Put the object onto the stack */

	walk_state->operands[walk_state->operand_index] = object;
	walk_state->num_operands++;

	/* For the usual order of filling the operand stack */

	walk_state->operand_index++;

	ACPI_DEBUG_PRINT((ACPI_DB_EXEC, "Obj=%p [%s] State=%p #Ops=%X\n",
			  object,
			  acpi_ut_get_object_type_name((union
							acpi_operand_object *)
						       object), walk_state,
			  walk_state->num_operands));

	return (AE_OK);
}

/*******************************************************************************
 *
 * FUNCTION:    acpi_ds_obj_stack_pop
 *
 * PARAMETERS:  pop_count           - Number of objects/entries to pop
 *              walk_state          - Current Walk state
 *
 * RETURN:      Status
 *
 * DESCRIPTION: Pop this walk's object stack. Objects on the stack are NOT
 *              deleted by this routine.
 *
 ******************************************************************************/

acpi_status
acpi_ds_obj_stack_pop(u32 pop_count, struct acpi_walk_state * walk_state)
{
	u32 i;

	ACPI_FUNCTION_NAME(ds_obj_stack_pop);

	for (i = 0; i < pop_count; i++) {

		/* Check for stack underflow */

		if (walk_state->num_operands == 0) {
			ACPI_ERROR((AE_INFO,
				    "Object stack underflow! Count=%X State=%p #Ops=%u",
				    pop_count, walk_state,
				    walk_state->num_operands));
			return (AE_STACK_UNDERFLOW);
		}

		/* Just set the stack entry to null */

		walk_state->num_operands--;
		walk_state->operands[walk_state->num_operands] = NULL;
	}

	ACPI_DEBUG_PRINT((ACPI_DB_EXEC, "Count=%X State=%p #Ops=%u\n",
			  pop_count, walk_state, walk_state->num_operands));

	return (AE_OK);
}

/*******************************************************************************
 *
 * FUNCTION:    acpi_ds_obj_stack_pop_and_delete
 *
 * PARAMETERS:  pop_count           - Number of objects/entries to pop
 *              walk_state          - Current Walk state
 *
 * RETURN:      Status
 *
 * DESCRIPTION: Pop this walk's object stack and delete each object that is
 *              popped off.
 *
 ******************************************************************************/

void
acpi_ds_obj_stack_pop_and_delete(u32 pop_count,
				 struct acpi_walk_state *walk_state)
{
	s32 i;
	union acpi_operand_object *obj_desc;

	ACPI_FUNCTION_NAME(ds_obj_stack_pop_and_delete);

	if (pop_count == 0) {
		return;
	}

	for (i = (s32) pop_count - 1; i >= 0; i--) {
		if (walk_state->num_operands == 0) {
			return;
		}

		/* Pop the stack and delete an object if present in this stack entry */

		walk_state->num_operands--;
		obj_desc = walk_state->operands[i];
		if (obj_desc) {
			acpi_ut_remove_reference(walk_state->operands[i]);
			walk_state->operands[i] = NULL;
		}
	}

	ACPI_DEBUG_PRINT((ACPI_DB_EXEC, "Count=%X State=%p #Ops=%X\n",
			  pop_count, walk_state, walk_state->num_operands));
}

/*******************************************************************************
 *
 * FUNCTION:    acpi_ds_get_current_walk_state
 *
 * PARAMETERS:  thread          - Get current active state for this Thread
 *
 * RETURN:      Pointer to the current walk state
 *
 * DESCRIPTION: Get the walk state that is at the head of the list (the "current"
 *              walk state.)
 *
 ******************************************************************************/

struct acpi_walk_state *acpi_ds_get_current_walk_state(struct acpi_thread_state
						       *thread)
{
	ACPI_FUNCTION_NAME(ds_get_current_walk_state);

	if (!thread) {
		return (NULL);
	}

	ACPI_DEBUG_PRINT((ACPI_DB_PARSE, "Current WalkState %p\n",
			  thread->walk_state_list));

	return (thread->walk_state_list);
}

/*******************************************************************************
 *
 * FUNCTION:    acpi_ds_push_walk_state
 *
 * PARAMETERS:  walk_state      - State to push
 *              thread          - Thread state object
 *
 * RETURN:      None
 *
 * DESCRIPTION: Place the Thread state at the head of the state list
 *
 ******************************************************************************/

void
acpi_ds_push_walk_state(struct acpi_walk_state *walk_state,
			struct acpi_thread_state *thread)
{
	ACPI_FUNCTION_TRACE(ds_push_walk_state);

	walk_state->next = thread->walk_state_list;
	thread->walk_state_list = walk_state;

	return_VOID;
}

/*******************************************************************************
 *
 * FUNCTION:    acpi_ds_pop_walk_state
 *
 * PARAMETERS:  thread      - Current thread state
 *
 * RETURN:      A walk_state object popped from the thread's stack
 *
 * DESCRIPTION: Remove and return the walkstate object that is at the head of
 *              the walk stack for the given walk list. NULL indicates that
 *              the list is empty.
 *
 ******************************************************************************/

struct acpi_walk_state *acpi_ds_pop_walk_state(struct acpi_thread_state *thread)
{
	struct acpi_walk_state *walk_state;

	ACPI_FUNCTION_TRACE(ds_pop_walk_state);

	walk_state = thread->walk_state_list;

	if (walk_state) {

		/* Next walk state becomes the current walk state */

		thread->walk_state_list = walk_state->next;

		/*
		 * Don't clear the NEXT field, this serves as an indicator
		 * that there is a parent WALK STATE
		 * Do Not: walk_state->Next = NULL;
		 */
	}

	return_PTR(walk_state);
}

/*******************************************************************************
 *
 * FUNCTION:    acpi_ds_create_walk_state
 *
 * PARAMETERS:  owner_id        - ID for object creation
 *              origin          - Starting point for this walk
 *              method_desc     - Method object
 *              thread          - Current thread state
 *
 * RETURN:      Pointer to the new walk state.
 *
 * DESCRIPTION: Allocate and initialize a new walk state. The current walk
 *              state is set to this new state.
 *
 ******************************************************************************/

struct acpi_walk_state *acpi_ds_create_walk_state(acpi_owner_id owner_id,
						  union acpi_parse_object
						  *origin,
						  union acpi_operand_object
						  *method_desc,
						  struct acpi_thread_state
						  *thread)
{
	struct acpi_walk_state *walk_state;

	ACPI_FUNCTION_TRACE(ds_create_walk_state);

	walk_state = ACPI_ALLOCATE_ZEROED(sizeof(struct acpi_walk_state));
	if (!walk_state) {
		return_PTR(NULL);
	}

	walk_state->descriptor_type = ACPI_DESC_TYPE_WALK;
	walk_state->method_desc = method_desc;
	walk_state->owner_id = owner_id;
	walk_state->origin = origin;
	walk_state->thread = thread;

	walk_state->parser_state.start_op = origin;

	/* Init the method args/local */

#if (!defined (ACPI_NO_METHOD_EXECUTION) && !defined (ACPI_CONSTANT_EVAL_ONLY))
	acpi_ds_method_data_init(walk_state);
#endif

	/* Put the new state at the head of the walk list */

	if (thread) {
		acpi_ds_push_walk_state(walk_state, thread);
	}

	return_PTR(walk_state);
}

/*******************************************************************************
 *
 * FUNCTION:    acpi_ds_init_aml_walk
 *
 * PARAMETERS:  walk_state      - New state to be initialized
 *              op              - Current parse op
 *              method_node     - Control method NS node, if any
 *              aml_start       - Start of AML
 *              aml_length      - Length of AML
 *              info            - Method info block (params, etc.)
 *              pass_number     - 1, 2, or 3
 *
 * RETURN:      Status
 *
 * DESCRIPTION: Initialize a walk state for a pass 1 or 2 parse tree walk
 *
 ******************************************************************************/

acpi_status
acpi_ds_init_aml_walk(struct acpi_walk_state *walk_state,
		      union acpi_parse_object *op,
		      struct acpi_namespace_node *method_node,
		      u8 * aml_start,
		      u32 aml_length,
		      struct acpi_evaluate_info *info, u8 pass_number)
{
	acpi_status status;
	struct acpi_parse_state *parser_state = &walk_state->parser_state;
	union acpi_parse_object *extra_op;

	ACPI_FUNCTION_TRACE(ds_init_aml_walk);

	walk_state->parser_state.aml =
	    walk_state->parser_state.aml_start = aml_start;
	walk_state->parser_state.aml_end =
	    walk_state->parser_state.pkg_end = aml_start + aml_length;

	/* The next_op of the next_walk will be the beginning of the method */

	walk_state->next_op = NULL;
	walk_state->pass_number = pass_number;

	if (info) {
		walk_state->params = info->parameters;
		walk_state->caller_return_desc = &info->return_object;
	}

	status = acpi_ps_init_scope(&walk_state->parser_state, op);
	if (ACPI_FAILURE(status)) {
		return_ACPI_STATUS(status);
	}

	if (method_node) {
		walk_state->parser_state.start_node = method_node;
		walk_state->walk_type = ACPI_WALK_METHOD;
		walk_state->method_node = method_node;
		walk_state->method_desc =
		    acpi_ns_get_attached_object(method_node);

		/* Push start scope on scope stack and make it current  */

		status =
		    acpi_ds_scope_stack_push(method_node, ACPI_TYPE_METHOD,
					     walk_state);
		if (ACPI_FAILURE(status)) {
			return_ACPI_STATUS(status);
		}

		/* Init the method arguments */

		status = acpi_ds_method_data_init_args(walk_state->params,
						       ACPI_METHOD_NUM_ARGS,
						       walk_state);
		if (ACPI_FAILURE(status)) {
			return_ACPI_STATUS(status);
		}
	} else {
		/*
		 * Setup the current scope.
		 * Find a Named Op that has a namespace node associated with it.
		 * search upwards from this Op. Current scope is the first
		 * Op with a namespace node.
		 */
		extra_op = parser_state->start_op;
		while (extra_op && !extra_op->common.node) {
			extra_op = extra_op->common.parent;
		}

		if (!extra_op) {
			parser_state->start_node = NULL;
		} else {
			parser_state->start_node = extra_op->common.node;
		}

		if (parser_state->start_node) {

			/* Push start scope on scope stack and make it current  */

			status =
			    acpi_ds_scope_stack_push(parser_state->start_node,
						     parser_state->start_node->
						     type, walk_state);
			if (ACPI_FAILURE(status)) {
				return_ACPI_STATUS(status);
			}
		}
	}

	status = acpi_ds_init_callbacks(walk_state, pass_number);
	return_ACPI_STATUS(status);
}

/*******************************************************************************
 *
 * FUNCTION:    acpi_ds_delete_walk_state
 *
 * PARAMETERS:  walk_state      - State to delete
 *
 * RETURN:      Status
 *
 * DESCRIPTION: Delete a walk state including all internal data structures
 *
 ******************************************************************************/

void acpi_ds_delete_walk_state(struct acpi_walk_state *walk_state)
{
	union acpi_generic_state *state;

	ACPI_FUNCTION_TRACE_PTR(ds_delete_walk_state, walk_state);

	if (!walk_state) {
		return_VOID;
	}

	if (walk_state->descriptor_type != ACPI_DESC_TYPE_WALK) {
		ACPI_ERROR((AE_INFO, "%p is not a valid walk state",
			    walk_state));
		return_VOID;
	}

	/* There should not be any open scopes */

	if (walk_state->parser_state.scope) {
		ACPI_ERROR((AE_INFO, "%p walk still has a scope list",
			    walk_state));
		acpi_ps_cleanup_scope(&walk_state->parser_state);
	}

	/* Always must free any linked control states */

	while (walk_state->control_state) {
		state = walk_state->control_state;
		walk_state->control_state = state->common.next;

		acpi_ut_delete_generic_state(state);
	}

	/* Always must free any linked parse states */

	while (walk_state->scope_info) {
		state = walk_state->scope_info;
		walk_state->scope_info = state->common.next;

		acpi_ut_delete_generic_state(state);
	}

	/* Always must free any stacked result states */

	while (walk_state->results) {
		state = walk_state->results;
		walk_state->results = state->common.next;

		acpi_ut_delete_generic_state(state);
	}

	ACPI_FREE(walk_state);
	return_VOID;
}