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1 /******************************************************************************
2  *
3  * Module Name: dswstate - Dispatcher parse tree walk management routines
4  *
5  *****************************************************************************/
6
7 /*
8  * Copyright (C) 2000 - 2013, 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 }