xref: /openbmc/linux/drivers/acpi/acpica/dswload2.c (revision 9a29f5fc)
1 // SPDX-License-Identifier: BSD-3-Clause OR GPL-2.0
2 /******************************************************************************
3  *
4  * Module Name: dswload2 - Dispatcher second pass namespace load callbacks
5  *
6  * Copyright (C) 2000 - 2022, Intel Corp.
7  *
8  *****************************************************************************/
9 
10 #include <acpi/acpi.h>
11 #include "accommon.h"
12 #include "acparser.h"
13 #include "amlcode.h"
14 #include "acdispat.h"
15 #include "acinterp.h"
16 #include "acnamesp.h"
17 #include "acevents.h"
18 #ifdef ACPI_EXEC_APP
19 #include "aecommon.h"
20 #endif
21 
22 #define _COMPONENT          ACPI_DISPATCHER
23 ACPI_MODULE_NAME("dswload2")
24 
25 /*******************************************************************************
26  *
27  * FUNCTION:    acpi_ds_load2_begin_op
28  *
29  * PARAMETERS:  walk_state      - Current state of the parse tree walk
30  *              out_op          - Where to return op if a new one is created
31  *
32  * RETURN:      Status
33  *
34  * DESCRIPTION: Descending callback used during the loading of ACPI tables.
35  *
36  ******************************************************************************/
37 acpi_status
38 acpi_ds_load2_begin_op(struct acpi_walk_state *walk_state,
39 		       union acpi_parse_object **out_op)
40 {
41 	union acpi_parse_object *op;
42 	struct acpi_namespace_node *node;
43 	acpi_status status;
44 	acpi_object_type object_type;
45 	char *buffer_ptr;
46 	u32 flags;
47 
48 	ACPI_FUNCTION_TRACE(ds_load2_begin_op);
49 
50 	op = walk_state->op;
51 	ACPI_DEBUG_PRINT((ACPI_DB_DISPATCH, "Op=%p State=%p\n", op,
52 			  walk_state));
53 
54 	if (op) {
55 		if ((walk_state->control_state) &&
56 		    (walk_state->control_state->common.state ==
57 		     ACPI_CONTROL_CONDITIONAL_EXECUTING)) {
58 
59 			/* We are executing a while loop outside of a method */
60 
61 			status = acpi_ds_exec_begin_op(walk_state, out_op);
62 			return_ACPI_STATUS(status);
63 		}
64 
65 		/* We only care about Namespace opcodes here */
66 
67 		if ((!(walk_state->op_info->flags & AML_NSOPCODE) &&
68 		     (walk_state->opcode != AML_INT_NAMEPATH_OP)) ||
69 		    (!(walk_state->op_info->flags & AML_NAMED))) {
70 			return_ACPI_STATUS(AE_OK);
71 		}
72 
73 		/* Get the name we are going to enter or lookup in the namespace */
74 
75 		if (walk_state->opcode == AML_INT_NAMEPATH_OP) {
76 
77 			/* For Namepath op, get the path string */
78 
79 			buffer_ptr = op->common.value.string;
80 			if (!buffer_ptr) {
81 
82 				/* No name, just exit */
83 
84 				return_ACPI_STATUS(AE_OK);
85 			}
86 		} else {
87 			/* Get name from the op */
88 
89 			buffer_ptr = ACPI_CAST_PTR(char, &op->named.name);
90 		}
91 	} else {
92 		/* Get the namestring from the raw AML */
93 
94 		buffer_ptr =
95 		    acpi_ps_get_next_namestring(&walk_state->parser_state);
96 	}
97 
98 	/* Map the opcode into an internal object type */
99 
100 	object_type = walk_state->op_info->object_type;
101 
102 	ACPI_DEBUG_PRINT((ACPI_DB_DISPATCH,
103 			  "State=%p Op=%p Type=%X\n", walk_state, op,
104 			  object_type));
105 
106 	switch (walk_state->opcode) {
107 	case AML_FIELD_OP:
108 	case AML_BANK_FIELD_OP:
109 	case AML_INDEX_FIELD_OP:
110 
111 		node = NULL;
112 		status = AE_OK;
113 		break;
114 
115 	case AML_INT_NAMEPATH_OP:
116 		/*
117 		 * The name_path is an object reference to an existing object.
118 		 * Don't enter the name into the namespace, but look it up
119 		 * for use later.
120 		 */
121 		status =
122 		    acpi_ns_lookup(walk_state->scope_info, buffer_ptr,
123 				   object_type, ACPI_IMODE_EXECUTE,
124 				   ACPI_NS_SEARCH_PARENT, walk_state, &(node));
125 		break;
126 
127 	case AML_SCOPE_OP:
128 
129 		/* Special case for Scope(\) -> refers to the Root node */
130 
131 		if (op && (op->named.node == acpi_gbl_root_node)) {
132 			node = op->named.node;
133 
134 			status =
135 			    acpi_ds_scope_stack_push(node, object_type,
136 						     walk_state);
137 			if (ACPI_FAILURE(status)) {
138 				return_ACPI_STATUS(status);
139 			}
140 		} else {
141 			/*
142 			 * The Path is an object reference to an existing object.
143 			 * Don't enter the name into the namespace, but look it up
144 			 * for use later.
145 			 */
146 			status =
147 			    acpi_ns_lookup(walk_state->scope_info, buffer_ptr,
148 					   object_type, ACPI_IMODE_EXECUTE,
149 					   ACPI_NS_SEARCH_PARENT, walk_state,
150 					   &(node));
151 			if (ACPI_FAILURE(status)) {
152 #ifdef ACPI_ASL_COMPILER
153 				if (status == AE_NOT_FOUND) {
154 					status = AE_OK;
155 				} else {
156 					ACPI_ERROR_NAMESPACE(walk_state->
157 							     scope_info,
158 							     buffer_ptr,
159 							     status);
160 				}
161 #else
162 				ACPI_ERROR_NAMESPACE(walk_state->scope_info,
163 						     buffer_ptr, status);
164 #endif
165 				return_ACPI_STATUS(status);
166 			}
167 		}
168 
169 		/*
170 		 * We must check to make sure that the target is
171 		 * one of the opcodes that actually opens a scope
172 		 */
173 		switch (node->type) {
174 		case ACPI_TYPE_ANY:
175 		case ACPI_TYPE_LOCAL_SCOPE:	/* Scope */
176 		case ACPI_TYPE_DEVICE:
177 		case ACPI_TYPE_POWER:
178 		case ACPI_TYPE_PROCESSOR:
179 		case ACPI_TYPE_THERMAL:
180 
181 			/* These are acceptable types */
182 			break;
183 
184 		case ACPI_TYPE_INTEGER:
185 		case ACPI_TYPE_STRING:
186 		case ACPI_TYPE_BUFFER:
187 
188 			/*
189 			 * These types we will allow, but we will change the type.
190 			 * This enables some existing code of the form:
191 			 *
192 			 *  Name (DEB, 0)
193 			 *  Scope (DEB) { ... }
194 			 */
195 			ACPI_WARNING((AE_INFO,
196 				      "Type override - [%4.4s] had invalid type (%s) "
197 				      "for Scope operator, changed to type ANY",
198 				      acpi_ut_get_node_name(node),
199 				      acpi_ut_get_type_name(node->type)));
200 
201 			node->type = ACPI_TYPE_ANY;
202 			walk_state->scope_info->common.value = ACPI_TYPE_ANY;
203 			break;
204 
205 		case ACPI_TYPE_METHOD:
206 
207 			/*
208 			 * Allow scope change to root during execution of module-level
209 			 * code. Root is typed METHOD during this time.
210 			 */
211 			if ((node == acpi_gbl_root_node) &&
212 			    (walk_state->
213 			     parse_flags & ACPI_PARSE_MODULE_LEVEL)) {
214 				break;
215 			}
216 
217 			ACPI_FALLTHROUGH;
218 
219 		default:
220 
221 			/* All other types are an error */
222 
223 			ACPI_ERROR((AE_INFO,
224 				    "Invalid type (%s) for target of "
225 				    "Scope operator [%4.4s] (Cannot override)",
226 				    acpi_ut_get_type_name(node->type),
227 				    acpi_ut_get_node_name(node)));
228 
229 			return_ACPI_STATUS(AE_AML_OPERAND_TYPE);
230 		}
231 		break;
232 
233 	default:
234 
235 		/* All other opcodes */
236 
237 		if (op && op->common.node) {
238 
239 			/* This op/node was previously entered into the namespace */
240 
241 			node = op->common.node;
242 
243 			if (acpi_ns_opens_scope(object_type)) {
244 				status =
245 				    acpi_ds_scope_stack_push(node, object_type,
246 							     walk_state);
247 				if (ACPI_FAILURE(status)) {
248 					return_ACPI_STATUS(status);
249 				}
250 			}
251 
252 			return_ACPI_STATUS(AE_OK);
253 		}
254 
255 		/*
256 		 * Enter the named type into the internal namespace. We enter the name
257 		 * as we go downward in the parse tree. Any necessary subobjects that
258 		 * involve arguments to the opcode must be created as we go back up the
259 		 * parse tree later.
260 		 *
261 		 * Note: Name may already exist if we are executing a deferred opcode.
262 		 */
263 		if (walk_state->deferred_node) {
264 
265 			/* This name is already in the namespace, get the node */
266 
267 			node = walk_state->deferred_node;
268 			status = AE_OK;
269 			break;
270 		}
271 
272 		flags = ACPI_NS_NO_UPSEARCH;
273 		if (walk_state->pass_number == ACPI_IMODE_EXECUTE) {
274 
275 			/* Execution mode, node cannot already exist, node is temporary */
276 
277 			flags |= ACPI_NS_ERROR_IF_FOUND;
278 
279 			if (!
280 			    (walk_state->
281 			     parse_flags & ACPI_PARSE_MODULE_LEVEL)) {
282 				flags |= ACPI_NS_TEMPORARY;
283 			}
284 		}
285 #ifdef ACPI_ASL_COMPILER
286 
287 		/*
288 		 * Do not open a scope for AML_EXTERNAL_OP
289 		 * acpi_ns_lookup can open a new scope based on the object type
290 		 * of this op. AML_EXTERNAL_OP is a declaration rather than a
291 		 * definition. In the case that this external is a method object,
292 		 * acpi_ns_lookup will open a new scope. However, an AML_EXTERNAL_OP
293 		 * associated with the ACPI_TYPE_METHOD is a declaration, rather than
294 		 * a definition. Flags is set to avoid opening a scope for any
295 		 * AML_EXTERNAL_OP.
296 		 */
297 		if (walk_state->opcode == AML_EXTERNAL_OP) {
298 			flags |= ACPI_NS_DONT_OPEN_SCOPE;
299 		}
300 #endif
301 
302 		/*
303 		 * For name creation opcodes, the full namepath prefix must
304 		 * exist, except for the final (new) nameseg.
305 		 */
306 		if (walk_state->op_info->flags & AML_NAMED) {
307 			flags |= ACPI_NS_PREFIX_MUST_EXIST;
308 		}
309 
310 		/* Add new entry or lookup existing entry */
311 
312 		status =
313 		    acpi_ns_lookup(walk_state->scope_info, buffer_ptr,
314 				   object_type, ACPI_IMODE_LOAD_PASS2, flags,
315 				   walk_state, &node);
316 
317 		if (ACPI_SUCCESS(status) && (flags & ACPI_NS_TEMPORARY)) {
318 			ACPI_DEBUG_PRINT((ACPI_DB_DISPATCH,
319 					  "***New Node [%4.4s] %p is temporary\n",
320 					  acpi_ut_get_node_name(node), node));
321 		}
322 		break;
323 	}
324 
325 	if (ACPI_FAILURE(status)) {
326 		ACPI_ERROR_NAMESPACE(walk_state->scope_info,
327 				     buffer_ptr, status);
328 		return_ACPI_STATUS(status);
329 	}
330 
331 	if (!op) {
332 
333 		/* Create a new op */
334 
335 		op = acpi_ps_alloc_op(walk_state->opcode, walk_state->aml);
336 		if (!op) {
337 			return_ACPI_STATUS(AE_NO_MEMORY);
338 		}
339 
340 		/* Initialize the new op */
341 
342 		if (node) {
343 			op->named.name = node->name.integer;
344 		}
345 		*out_op = op;
346 	}
347 
348 	/*
349 	 * Put the Node in the "op" object that the parser uses, so we
350 	 * can get it again quickly when this scope is closed
351 	 */
352 	op->common.node = node;
353 	return_ACPI_STATUS(status);
354 }
355 
356 /*******************************************************************************
357  *
358  * FUNCTION:    acpi_ds_load2_end_op
359  *
360  * PARAMETERS:  walk_state      - Current state of the parse tree walk
361  *
362  * RETURN:      Status
363  *
364  * DESCRIPTION: Ascending callback used during the loading of the namespace,
365  *              both control methods and everything else.
366  *
367  ******************************************************************************/
368 
369 acpi_status acpi_ds_load2_end_op(struct acpi_walk_state *walk_state)
370 {
371 	union acpi_parse_object *op;
372 	acpi_status status = AE_OK;
373 	acpi_object_type object_type;
374 	struct acpi_namespace_node *node;
375 	union acpi_parse_object *arg;
376 	struct acpi_namespace_node *new_node;
377 	u32 i;
378 	u8 region_space;
379 #ifdef ACPI_EXEC_APP
380 	union acpi_operand_object *obj_desc;
381 	char *namepath;
382 #endif
383 
384 	ACPI_FUNCTION_TRACE(ds_load2_end_op);
385 
386 	op = walk_state->op;
387 	ACPI_DEBUG_PRINT((ACPI_DB_DISPATCH, "Opcode [%s] Op %p State %p\n",
388 			  walk_state->op_info->name, op, walk_state));
389 
390 	/* Check if opcode had an associated namespace object */
391 
392 	if (!(walk_state->op_info->flags & AML_NSOBJECT)) {
393 		return_ACPI_STATUS(AE_OK);
394 	}
395 
396 	if (op->common.aml_opcode == AML_SCOPE_OP) {
397 		ACPI_DEBUG_PRINT((ACPI_DB_DISPATCH,
398 				  "Ending scope Op=%p State=%p\n", op,
399 				  walk_state));
400 	}
401 
402 	object_type = walk_state->op_info->object_type;
403 
404 	/*
405 	 * Get the Node/name from the earlier lookup
406 	 * (It was saved in the *op structure)
407 	 */
408 	node = op->common.node;
409 
410 	/*
411 	 * Put the Node on the object stack (Contains the ACPI Name of
412 	 * this object)
413 	 */
414 	walk_state->operands[0] = (void *)node;
415 	walk_state->num_operands = 1;
416 
417 	/* Pop the scope stack */
418 
419 	if (acpi_ns_opens_scope(object_type) &&
420 	    (op->common.aml_opcode != AML_INT_METHODCALL_OP)) {
421 		ACPI_DEBUG_PRINT((ACPI_DB_DISPATCH,
422 				  "(%s) Popping scope for Op %p\n",
423 				  acpi_ut_get_type_name(object_type), op));
424 
425 		status = acpi_ds_scope_stack_pop(walk_state);
426 		if (ACPI_FAILURE(status)) {
427 			goto cleanup;
428 		}
429 	}
430 
431 	/*
432 	 * Named operations are as follows:
433 	 *
434 	 * AML_ALIAS
435 	 * AML_BANKFIELD
436 	 * AML_CREATEBITFIELD
437 	 * AML_CREATEBYTEFIELD
438 	 * AML_CREATEDWORDFIELD
439 	 * AML_CREATEFIELD
440 	 * AML_CREATEQWORDFIELD
441 	 * AML_CREATEWORDFIELD
442 	 * AML_DATA_REGION
443 	 * AML_DEVICE
444 	 * AML_EVENT
445 	 * AML_FIELD
446 	 * AML_INDEXFIELD
447 	 * AML_METHOD
448 	 * AML_METHODCALL
449 	 * AML_MUTEX
450 	 * AML_NAME
451 	 * AML_NAMEDFIELD
452 	 * AML_OPREGION
453 	 * AML_POWERRES
454 	 * AML_PROCESSOR
455 	 * AML_SCOPE
456 	 * AML_THERMALZONE
457 	 */
458 
459 	ACPI_DEBUG_PRINT((ACPI_DB_DISPATCH,
460 			  "Create-Load [%s] State=%p Op=%p NamedObj=%p\n",
461 			  acpi_ps_get_opcode_name(op->common.aml_opcode),
462 			  walk_state, op, node));
463 
464 	/* Decode the opcode */
465 
466 	arg = op->common.value.arg;
467 
468 	switch (walk_state->op_info->type) {
469 
470 	case AML_TYPE_CREATE_FIELD:
471 		/*
472 		 * Create the field object, but the field buffer and index must
473 		 * be evaluated later during the execution phase
474 		 */
475 		status = acpi_ds_create_buffer_field(op, walk_state);
476 		if (ACPI_FAILURE(status)) {
477 			ACPI_EXCEPTION((AE_INFO, status,
478 					"CreateBufferField failure"));
479 			goto cleanup;
480 			}
481 		break;
482 
483 	case AML_TYPE_NAMED_FIELD:
484 		/*
485 		 * If we are executing a method, initialize the field
486 		 */
487 		if (walk_state->method_node) {
488 			status = acpi_ds_init_field_objects(op, walk_state);
489 		}
490 
491 		switch (op->common.aml_opcode) {
492 		case AML_INDEX_FIELD_OP:
493 
494 			status =
495 			    acpi_ds_create_index_field(op,
496 						       (acpi_handle)arg->common.
497 						       node, walk_state);
498 			break;
499 
500 		case AML_BANK_FIELD_OP:
501 
502 			status =
503 			    acpi_ds_create_bank_field(op, arg->common.node,
504 						      walk_state);
505 			break;
506 
507 		case AML_FIELD_OP:
508 
509 			status =
510 			    acpi_ds_create_field(op, arg->common.node,
511 						 walk_state);
512 			break;
513 
514 		default:
515 
516 			/* All NAMED_FIELD opcodes must be handled above */
517 			break;
518 		}
519 		break;
520 
521 	case AML_TYPE_NAMED_SIMPLE:
522 
523 		status = acpi_ds_create_operands(walk_state, arg);
524 		if (ACPI_FAILURE(status)) {
525 			goto cleanup;
526 		}
527 
528 		switch (op->common.aml_opcode) {
529 		case AML_PROCESSOR_OP:
530 
531 			status = acpi_ex_create_processor(walk_state);
532 			break;
533 
534 		case AML_POWER_RESOURCE_OP:
535 
536 			status = acpi_ex_create_power_resource(walk_state);
537 			break;
538 
539 		case AML_MUTEX_OP:
540 
541 			status = acpi_ex_create_mutex(walk_state);
542 			break;
543 
544 		case AML_EVENT_OP:
545 
546 			status = acpi_ex_create_event(walk_state);
547 			break;
548 
549 		case AML_ALIAS_OP:
550 
551 			status = acpi_ex_create_alias(walk_state);
552 			break;
553 
554 		default:
555 
556 			/* Unknown opcode */
557 
558 			status = AE_OK;
559 			goto cleanup;
560 		}
561 
562 		/* Delete operands */
563 
564 		for (i = 1; i < walk_state->num_operands; i++) {
565 			acpi_ut_remove_reference(walk_state->operands[i]);
566 			walk_state->operands[i] = NULL;
567 		}
568 
569 		break;
570 
571 	case AML_TYPE_NAMED_COMPLEX:
572 
573 		switch (op->common.aml_opcode) {
574 		case AML_REGION_OP:
575 		case AML_DATA_REGION_OP:
576 
577 			if (op->common.aml_opcode == AML_REGION_OP) {
578 				region_space = (acpi_adr_space_type)
579 				    ((op->common.value.arg)->common.value.
580 				     integer);
581 			} else {
582 				region_space = ACPI_ADR_SPACE_DATA_TABLE;
583 			}
584 
585 			/*
586 			 * The op_region is not fully parsed at this time. The only valid
587 			 * argument is the space_id. (We must save the address of the
588 			 * AML of the address and length operands)
589 			 *
590 			 * If we have a valid region, initialize it. The namespace is
591 			 * unlocked at this point.
592 			 *
593 			 * Need to unlock interpreter if it is locked (if we are running
594 			 * a control method), in order to allow _REG methods to be run
595 			 * during acpi_ev_initialize_region.
596 			 */
597 			if (walk_state->method_node) {
598 				/*
599 				 * Executing a method: initialize the region and unlock
600 				 * the interpreter
601 				 */
602 				status = acpi_ex_create_region(op->named.data,
603 							       op->named.length,
604 							       region_space,
605 							       walk_state);
606 				if (ACPI_FAILURE(status)) {
607 					return_ACPI_STATUS(status);
608 				}
609 			}
610 
611 			status =
612 			    acpi_ev_initialize_region
613 			    (acpi_ns_get_attached_object(node));
614 			break;
615 
616 		case AML_NAME_OP:
617 
618 			status = acpi_ds_create_node(walk_state, node, op);
619 			if (ACPI_FAILURE(status)) {
620 				goto cleanup;
621 			}
622 #ifdef ACPI_EXEC_APP
623 			/*
624 			 * acpi_exec support for namespace initialization file (initialize
625 			 * Name opcodes in this code.)
626 			 */
627 			namepath = acpi_ns_get_external_pathname(node);
628 			status = ae_lookup_init_file_entry(namepath, &obj_desc);
629 			if (ACPI_SUCCESS(status)) {
630 
631 				/* Detach any existing object, attach new object */
632 
633 				if (node->object) {
634 					acpi_ns_detach_object(node);
635 				}
636 				acpi_ns_attach_object(node, obj_desc,
637 						      obj_desc->common.type);
638 			}
639 			ACPI_FREE(namepath);
640 			status = AE_OK;
641 #endif
642 			break;
643 
644 		case AML_METHOD_OP:
645 			/*
646 			 * method_op pkg_length name_string method_flags term_list
647 			 *
648 			 * Note: We must create the method node/object pair as soon as we
649 			 * see the method declaration. This allows later pass1 parsing
650 			 * of invocations of the method (need to know the number of
651 			 * arguments.)
652 			 */
653 			ACPI_DEBUG_PRINT((ACPI_DB_DISPATCH,
654 					  "LOADING-Method: State=%p Op=%p NamedObj=%p\n",
655 					  walk_state, op, op->named.node));
656 
657 			if (!acpi_ns_get_attached_object(op->named.node)) {
658 				walk_state->operands[0] =
659 				    ACPI_CAST_PTR(void, op->named.node);
660 				walk_state->num_operands = 1;
661 
662 				status =
663 				    acpi_ds_create_operands(walk_state,
664 							    op->common.value.
665 							    arg);
666 				if (ACPI_SUCCESS(status)) {
667 					status =
668 					    acpi_ex_create_method(op->named.
669 								  data,
670 								  op->named.
671 								  length,
672 								  walk_state);
673 				}
674 
675 				walk_state->operands[0] = NULL;
676 				walk_state->num_operands = 0;
677 
678 				if (ACPI_FAILURE(status)) {
679 					return_ACPI_STATUS(status);
680 				}
681 			}
682 			break;
683 
684 		default:
685 
686 			/* All NAMED_COMPLEX opcodes must be handled above */
687 			break;
688 		}
689 		break;
690 
691 	case AML_CLASS_INTERNAL:
692 
693 		/* case AML_INT_NAMEPATH_OP: */
694 		break;
695 
696 	case AML_CLASS_METHOD_CALL:
697 
698 		ACPI_DEBUG_PRINT((ACPI_DB_DISPATCH,
699 				  "RESOLVING-MethodCall: State=%p Op=%p NamedObj=%p\n",
700 				  walk_state, op, node));
701 
702 		/*
703 		 * Lookup the method name and save the Node
704 		 */
705 		status =
706 		    acpi_ns_lookup(walk_state->scope_info,
707 				   arg->common.value.string, ACPI_TYPE_ANY,
708 				   ACPI_IMODE_LOAD_PASS2,
709 				   ACPI_NS_SEARCH_PARENT |
710 				   ACPI_NS_DONT_OPEN_SCOPE, walk_state,
711 				   &(new_node));
712 		if (ACPI_SUCCESS(status)) {
713 			/*
714 			 * Make sure that what we found is indeed a method
715 			 * We didn't search for a method on purpose, to see if the name
716 			 * would resolve
717 			 */
718 			if (new_node->type != ACPI_TYPE_METHOD) {
719 				status = AE_AML_OPERAND_TYPE;
720 			}
721 
722 			/* We could put the returned object (Node) on the object stack for
723 			 * later, but for now, we will put it in the "op" object that the
724 			 * parser uses, so we can get it again at the end of this scope
725 			 */
726 			op->common.node = new_node;
727 		} else {
728 			ACPI_ERROR_NAMESPACE(walk_state->scope_info,
729 					     arg->common.value.string, status);
730 		}
731 		break;
732 
733 	default:
734 
735 		break;
736 	}
737 
738 cleanup:
739 
740 	/* Remove the Node pushed at the very beginning */
741 
742 	walk_state->operands[0] = NULL;
743 	walk_state->num_operands = 0;
744 	return_ACPI_STATUS(status);
745 }
746