1 // SPDX-License-Identifier: BSD-3-Clause OR GPL-2.0
2 /******************************************************************************
3  *
4  * Module Name: dswexec - Dispatcher method execution callbacks;
5  *                        dispatch to interpreter.
6  *
7  * Copyright (C) 2000 - 2021, Intel Corp.
8  *
9  *****************************************************************************/
10 
11 #include <acpi/acpi.h>
12 #include "accommon.h"
13 #include "acparser.h"
14 #include "amlcode.h"
15 #include "acdispat.h"
16 #include "acinterp.h"
17 #include "acnamesp.h"
18 #include "acdebug.h"
19 #ifdef ACPI_EXEC_APP
20 #include "aecommon.h"
21 #endif
22 
23 #define _COMPONENT          ACPI_DISPATCHER
24 ACPI_MODULE_NAME("dswexec")
25 
26 /*
27  * Dispatch table for opcode classes
28  */
29 static acpi_execute_op acpi_gbl_op_type_dispatch[] = {
30 	acpi_ex_opcode_0A_0T_1R,
31 	acpi_ex_opcode_1A_0T_0R,
32 	acpi_ex_opcode_1A_0T_1R,
33 	acpi_ex_opcode_1A_1T_0R,
34 	acpi_ex_opcode_1A_1T_1R,
35 	acpi_ex_opcode_2A_0T_0R,
36 	acpi_ex_opcode_2A_0T_1R,
37 	acpi_ex_opcode_2A_1T_1R,
38 	acpi_ex_opcode_2A_2T_1R,
39 	acpi_ex_opcode_3A_0T_0R,
40 	acpi_ex_opcode_3A_1T_1R,
41 	acpi_ex_opcode_6A_0T_1R
42 };
43 
44 /*****************************************************************************
45  *
46  * FUNCTION:    acpi_ds_get_predicate_value
47  *
48  * PARAMETERS:  walk_state      - Current state of the parse tree walk
49  *              result_obj      - if non-zero, pop result from result stack
50  *
51  * RETURN:      Status
52  *
53  * DESCRIPTION: Get the result of a predicate evaluation
54  *
55  ****************************************************************************/
56 
57 acpi_status
acpi_ds_get_predicate_value(struct acpi_walk_state * walk_state,union acpi_operand_object * result_obj)58 acpi_ds_get_predicate_value(struct acpi_walk_state *walk_state,
59 			    union acpi_operand_object *result_obj)
60 {
61 	acpi_status status = AE_OK;
62 	union acpi_operand_object *obj_desc;
63 	union acpi_operand_object *local_obj_desc = NULL;
64 
65 	ACPI_FUNCTION_TRACE_PTR(ds_get_predicate_value, walk_state);
66 
67 	walk_state->control_state->common.state = 0;
68 
69 	if (result_obj) {
70 		status = acpi_ds_result_pop(&obj_desc, walk_state);
71 		if (ACPI_FAILURE(status)) {
72 			ACPI_EXCEPTION((AE_INFO, status,
73 					"Could not get result from predicate evaluation"));
74 
75 			return_ACPI_STATUS(status);
76 		}
77 	} else {
78 		status = acpi_ds_create_operand(walk_state, walk_state->op, 0);
79 		if (ACPI_FAILURE(status)) {
80 			return_ACPI_STATUS(status);
81 		}
82 
83 		status =
84 		    acpi_ex_resolve_to_value(&walk_state->operands[0],
85 					     walk_state);
86 		if (ACPI_FAILURE(status)) {
87 			return_ACPI_STATUS(status);
88 		}
89 
90 		obj_desc = walk_state->operands[0];
91 	}
92 
93 	if (!obj_desc) {
94 		ACPI_ERROR((AE_INFO,
95 			    "No predicate ObjDesc=%p State=%p",
96 			    obj_desc, walk_state));
97 
98 		return_ACPI_STATUS(AE_AML_NO_OPERAND);
99 	}
100 
101 	/*
102 	 * Result of predicate evaluation must be an Integer
103 	 * object. Implicitly convert the argument if necessary.
104 	 */
105 	status = acpi_ex_convert_to_integer(obj_desc, &local_obj_desc,
106 					    ACPI_IMPLICIT_CONVERSION);
107 	if (ACPI_FAILURE(status)) {
108 		goto cleanup;
109 	}
110 
111 	if (local_obj_desc->common.type != ACPI_TYPE_INTEGER) {
112 		ACPI_ERROR((AE_INFO,
113 			    "Bad predicate (not an integer) ObjDesc=%p State=%p Type=0x%X",
114 			    obj_desc, walk_state, obj_desc->common.type));
115 
116 		status = AE_AML_OPERAND_TYPE;
117 		goto cleanup;
118 	}
119 
120 	/* Truncate the predicate to 32-bits if necessary */
121 
122 	(void)acpi_ex_truncate_for32bit_table(local_obj_desc);
123 
124 	/*
125 	 * Save the result of the predicate evaluation on
126 	 * the control stack
127 	 */
128 	if (local_obj_desc->integer.value) {
129 		walk_state->control_state->common.value = TRUE;
130 	} else {
131 		/*
132 		 * Predicate is FALSE, we will just toss the
133 		 * rest of the package
134 		 */
135 		walk_state->control_state->common.value = FALSE;
136 		status = AE_CTRL_FALSE;
137 	}
138 
139 	/* Predicate can be used for an implicit return value */
140 
141 	(void)acpi_ds_do_implicit_return(local_obj_desc, walk_state, TRUE);
142 
143 cleanup:
144 
145 	ACPI_DEBUG_PRINT((ACPI_DB_EXEC,
146 			  "Completed a predicate eval=%X Op=%p\n",
147 			  walk_state->control_state->common.value,
148 			  walk_state->op));
149 
150 	/* Break to debugger to display result */
151 
152 	acpi_db_display_result_object(local_obj_desc, walk_state);
153 
154 	/*
155 	 * Delete the predicate result object (we know that
156 	 * we don't need it anymore)
157 	 */
158 	if (local_obj_desc != obj_desc) {
159 		acpi_ut_remove_reference(local_obj_desc);
160 	}
161 	acpi_ut_remove_reference(obj_desc);
162 
163 	walk_state->control_state->common.state = ACPI_CONTROL_NORMAL;
164 	return_ACPI_STATUS(status);
165 }
166 
167 /*****************************************************************************
168  *
169  * FUNCTION:    acpi_ds_exec_begin_op
170  *
171  * PARAMETERS:  walk_state      - Current state of the parse tree walk
172  *              out_op          - Where to return op if a new one is created
173  *
174  * RETURN:      Status
175  *
176  * DESCRIPTION: Descending callback used during the execution of control
177  *              methods. This is where most operators and operands are
178  *              dispatched to the interpreter.
179  *
180  ****************************************************************************/
181 
182 acpi_status
acpi_ds_exec_begin_op(struct acpi_walk_state * walk_state,union acpi_parse_object ** out_op)183 acpi_ds_exec_begin_op(struct acpi_walk_state *walk_state,
184 		      union acpi_parse_object **out_op)
185 {
186 	union acpi_parse_object *op;
187 	acpi_status status = AE_OK;
188 	u32 opcode_class;
189 
190 	ACPI_FUNCTION_TRACE_PTR(ds_exec_begin_op, walk_state);
191 
192 	op = walk_state->op;
193 	if (!op) {
194 		status = acpi_ds_load2_begin_op(walk_state, out_op);
195 		if (ACPI_FAILURE(status)) {
196 			goto error_exit;
197 		}
198 
199 		op = *out_op;
200 		walk_state->op = op;
201 		walk_state->opcode = op->common.aml_opcode;
202 		walk_state->op_info =
203 		    acpi_ps_get_opcode_info(op->common.aml_opcode);
204 
205 		if (acpi_ns_opens_scope(walk_state->op_info->object_type)) {
206 			ACPI_DEBUG_PRINT((ACPI_DB_DISPATCH,
207 					  "(%s) Popping scope for Op %p\n",
208 					  acpi_ut_get_type_name(walk_state->
209 								op_info->
210 								object_type),
211 					  op));
212 
213 			status = acpi_ds_scope_stack_pop(walk_state);
214 			if (ACPI_FAILURE(status)) {
215 				goto error_exit;
216 			}
217 		}
218 	}
219 
220 	if (op == walk_state->origin) {
221 		if (out_op) {
222 			*out_op = op;
223 		}
224 
225 		return_ACPI_STATUS(AE_OK);
226 	}
227 
228 	/*
229 	 * If the previous opcode was a conditional, this opcode
230 	 * must be the beginning of the associated predicate.
231 	 * Save this knowledge in the current scope descriptor
232 	 */
233 	if ((walk_state->control_state) &&
234 	    (walk_state->control_state->common.state ==
235 	     ACPI_CONTROL_CONDITIONAL_EXECUTING)) {
236 		ACPI_DEBUG_PRINT((ACPI_DB_EXEC,
237 				  "Exec predicate Op=%p State=%p\n",
238 				  op, walk_state));
239 
240 		walk_state->control_state->common.state =
241 		    ACPI_CONTROL_PREDICATE_EXECUTING;
242 
243 		/* Save start of predicate */
244 
245 		walk_state->control_state->control.predicate_op = op;
246 	}
247 
248 	opcode_class = walk_state->op_info->class;
249 
250 	/* We want to send namepaths to the load code */
251 
252 	if (op->common.aml_opcode == AML_INT_NAMEPATH_OP) {
253 		opcode_class = AML_CLASS_NAMED_OBJECT;
254 	}
255 
256 	/*
257 	 * Handle the opcode based upon the opcode type
258 	 */
259 	switch (opcode_class) {
260 	case AML_CLASS_CONTROL:
261 
262 		status = acpi_ds_exec_begin_control_op(walk_state, op);
263 		break;
264 
265 	case AML_CLASS_NAMED_OBJECT:
266 
267 		if (walk_state->walk_type & ACPI_WALK_METHOD) {
268 			/*
269 			 * Found a named object declaration during method execution;
270 			 * we must enter this object into the namespace. The created
271 			 * object is temporary and will be deleted upon completion of
272 			 * the execution of this method.
273 			 *
274 			 * Note 10/2010: Except for the Scope() op. This opcode does
275 			 * not actually create a new object, it refers to an existing
276 			 * object. However, for Scope(), we want to indeed open a
277 			 * new scope.
278 			 */
279 			if (op->common.aml_opcode != AML_SCOPE_OP) {
280 				status =
281 				    acpi_ds_load2_begin_op(walk_state, NULL);
282 			} else {
283 				status =
284 				    acpi_ds_scope_stack_push(op->named.node,
285 							     op->named.node->
286 							     type, walk_state);
287 				if (ACPI_FAILURE(status)) {
288 					return_ACPI_STATUS(status);
289 				}
290 			}
291 		}
292 		break;
293 
294 	case AML_CLASS_EXECUTE:
295 	case AML_CLASS_CREATE:
296 
297 		break;
298 
299 	default:
300 
301 		break;
302 	}
303 
304 	/* Nothing to do here during method execution */
305 
306 	return_ACPI_STATUS(status);
307 
308 error_exit:
309 	status = acpi_ds_method_error(status, walk_state);
310 	return_ACPI_STATUS(status);
311 }
312 
313 /*****************************************************************************
314  *
315  * FUNCTION:    acpi_ds_exec_end_op
316  *
317  * PARAMETERS:  walk_state      - Current state of the parse tree walk
318  *
319  * RETURN:      Status
320  *
321  * DESCRIPTION: Ascending callback used during the execution of control
322  *              methods. The only thing we really need to do here is to
323  *              notice the beginning of IF, ELSE, and WHILE blocks.
324  *
325  ****************************************************************************/
326 
acpi_ds_exec_end_op(struct acpi_walk_state * walk_state)327 acpi_status acpi_ds_exec_end_op(struct acpi_walk_state *walk_state)
328 {
329 	union acpi_parse_object *op;
330 	acpi_status status = AE_OK;
331 	u32 op_type;
332 	u32 op_class;
333 	union acpi_parse_object *next_op;
334 	union acpi_parse_object *first_arg;
335 #ifdef ACPI_EXEC_APP
336 	char *namepath;
337 	union acpi_operand_object *obj_desc;
338 #endif
339 
340 	ACPI_FUNCTION_TRACE_PTR(ds_exec_end_op, walk_state);
341 
342 	op = walk_state->op;
343 	op_type = walk_state->op_info->type;
344 	op_class = walk_state->op_info->class;
345 
346 	if (op_class == AML_CLASS_UNKNOWN) {
347 		ACPI_ERROR((AE_INFO, "Unknown opcode 0x%X",
348 			    op->common.aml_opcode));
349 		return_ACPI_STATUS(AE_NOT_IMPLEMENTED);
350 	}
351 
352 	first_arg = op->common.value.arg;
353 
354 	/* Init the walk state */
355 
356 	walk_state->num_operands = 0;
357 	walk_state->operand_index = 0;
358 	walk_state->return_desc = NULL;
359 	walk_state->result_obj = NULL;
360 
361 	/* Call debugger for single step support (DEBUG build only) */
362 
363 	status = acpi_db_single_step(walk_state, op, op_class);
364 	if (ACPI_FAILURE(status)) {
365 		return_ACPI_STATUS(status);
366 	}
367 
368 	/* Decode the Opcode Class */
369 
370 	switch (op_class) {
371 	case AML_CLASS_ARGUMENT:	/* Constants, literals, etc. */
372 
373 		if (walk_state->opcode == AML_INT_NAMEPATH_OP) {
374 			status = acpi_ds_evaluate_name_path(walk_state);
375 			if (ACPI_FAILURE(status)) {
376 				goto cleanup;
377 			}
378 		}
379 		break;
380 
381 	case AML_CLASS_EXECUTE:	/* Most operators with arguments */
382 
383 		/* Build resolved operand stack */
384 
385 		status = acpi_ds_create_operands(walk_state, first_arg);
386 		if (ACPI_FAILURE(status)) {
387 			goto cleanup;
388 		}
389 
390 		/*
391 		 * All opcodes require operand resolution, with the only exceptions
392 		 * being the object_type and size_of operators.
393 		 */
394 		if (!(walk_state->op_info->flags & AML_NO_OPERAND_RESOLVE)) {
395 
396 			/* Resolve all operands */
397 
398 			status = acpi_ex_resolve_operands(walk_state->opcode,
399 							  &(walk_state->
400 							    operands
401 							    [walk_state->
402 							     num_operands - 1]),
403 							  walk_state);
404 		}
405 
406 		if (ACPI_SUCCESS(status)) {
407 			/*
408 			 * Dispatch the request to the appropriate interpreter handler
409 			 * routine. There is one routine per opcode "type" based upon the
410 			 * number of opcode arguments and return type.
411 			 */
412 			status =
413 			    acpi_gbl_op_type_dispatch[op_type] (walk_state);
414 		} else {
415 			/*
416 			 * Treat constructs of the form "Store(LocalX,LocalX)" as noops when the
417 			 * Local is uninitialized.
418 			 */
419 			if ((status == AE_AML_UNINITIALIZED_LOCAL) &&
420 			    (walk_state->opcode == AML_STORE_OP) &&
421 			    (walk_state->operands[0]->common.type ==
422 			     ACPI_TYPE_LOCAL_REFERENCE)
423 			    && (walk_state->operands[1]->common.type ==
424 				ACPI_TYPE_LOCAL_REFERENCE)
425 			    && (walk_state->operands[0]->reference.class ==
426 				walk_state->operands[1]->reference.class)
427 			    && (walk_state->operands[0]->reference.value ==
428 				walk_state->operands[1]->reference.value)) {
429 				status = AE_OK;
430 			} else {
431 				ACPI_EXCEPTION((AE_INFO, status,
432 						"While resolving operands for [%s]",
433 						acpi_ps_get_opcode_name
434 						(walk_state->opcode)));
435 			}
436 		}
437 
438 		/* Always delete the argument objects and clear the operand stack */
439 
440 		acpi_ds_clear_operands(walk_state);
441 
442 		/*
443 		 * If a result object was returned from above, push it on the
444 		 * current result stack
445 		 */
446 		if (ACPI_SUCCESS(status) && walk_state->result_obj) {
447 			status =
448 			    acpi_ds_result_push(walk_state->result_obj,
449 						walk_state);
450 		}
451 		break;
452 
453 	default:
454 
455 		switch (op_type) {
456 		case AML_TYPE_CONTROL:	/* Type 1 opcode, IF/ELSE/WHILE/NOOP */
457 
458 			/* 1 Operand, 0 external_result, 0 internal_result */
459 
460 			status = acpi_ds_exec_end_control_op(walk_state, op);
461 
462 			break;
463 
464 		case AML_TYPE_METHOD_CALL:
465 			/*
466 			 * If the method is referenced from within a package
467 			 * declaration, it is not a invocation of the method, just
468 			 * a reference to it.
469 			 */
470 			if ((op->asl.parent) &&
471 			    ((op->asl.parent->asl.aml_opcode == AML_PACKAGE_OP)
472 			     || (op->asl.parent->asl.aml_opcode ==
473 				 AML_VARIABLE_PACKAGE_OP))) {
474 				ACPI_DEBUG_PRINT((ACPI_DB_DISPATCH,
475 						  "Method Reference in a Package, Op=%p\n",
476 						  op));
477 
478 				op->common.node = (struct acpi_namespace_node *)
479 				    op->asl.value.arg->asl.node;
480 				acpi_ut_add_reference(op->asl.value.arg->asl.
481 						      node->object);
482 				return_ACPI_STATUS(AE_OK);
483 			}
484 
485 			ACPI_DEBUG_PRINT((ACPI_DB_DISPATCH,
486 					  "Method invocation, Op=%p\n", op));
487 
488 			/*
489 			 * (AML_METHODCALL) Op->Asl.Value.Arg->Asl.Node contains
490 			 * the method Node pointer
491 			 */
492 			/* next_op points to the op that holds the method name */
493 
494 			next_op = first_arg;
495 
496 			/* next_op points to first argument op */
497 
498 			next_op = next_op->common.next;
499 
500 			/*
501 			 * Get the method's arguments and put them on the operand stack
502 			 */
503 			status = acpi_ds_create_operands(walk_state, next_op);
504 			if (ACPI_FAILURE(status)) {
505 				break;
506 			}
507 
508 			/*
509 			 * Since the operands will be passed to another control method,
510 			 * we must resolve all local references here (Local variables,
511 			 * arguments to *this* method, etc.)
512 			 */
513 			status = acpi_ds_resolve_operands(walk_state);
514 			if (ACPI_FAILURE(status)) {
515 
516 				/* On error, clear all resolved operands */
517 
518 				acpi_ds_clear_operands(walk_state);
519 				break;
520 			}
521 
522 			/*
523 			 * Tell the walk loop to preempt this running method and
524 			 * execute the new method
525 			 */
526 			status = AE_CTRL_TRANSFER;
527 
528 			/*
529 			 * Return now; we don't want to disturb anything,
530 			 * especially the operand count!
531 			 */
532 			return_ACPI_STATUS(status);
533 
534 		case AML_TYPE_CREATE_FIELD:
535 
536 			ACPI_DEBUG_PRINT((ACPI_DB_EXEC,
537 					  "Executing CreateField Buffer/Index Op=%p\n",
538 					  op));
539 
540 			status = acpi_ds_load2_end_op(walk_state);
541 			if (ACPI_FAILURE(status)) {
542 				break;
543 			}
544 
545 			status =
546 			    acpi_ds_eval_buffer_field_operands(walk_state, op);
547 			if (ACPI_FAILURE(status)) {
548 				break;
549 			}
550 #ifdef ACPI_EXEC_APP
551 			/*
552 			 * acpi_exec support for namespace initialization file (initialize
553 			 * buffer_fields in this code.)
554 			 */
555 			namepath =
556 			    acpi_ns_get_external_pathname(op->common.node);
557 			status = ae_lookup_init_file_entry(namepath, &obj_desc);
558 			if (ACPI_SUCCESS(status)) {
559 				status =
560 				    acpi_ex_write_data_to_field(obj_desc,
561 								op->common.
562 								node->object,
563 								NULL);
564 				if (ACPI_FAILURE(status)) {
565 					ACPI_EXCEPTION((AE_INFO, status,
566 							"While writing to buffer field"));
567 				}
568 			}
569 			ACPI_FREE(namepath);
570 			status = AE_OK;
571 #endif
572 			break;
573 
574 		case AML_TYPE_CREATE_OBJECT:
575 
576 			ACPI_DEBUG_PRINT((ACPI_DB_EXEC,
577 					  "Executing CreateObject (Buffer/Package) Op=%p Child=%p ParentOpcode=%4.4X\n",
578 					  op, op->named.value.arg,
579 					  op->common.parent->common.
580 					  aml_opcode));
581 
582 			switch (op->common.parent->common.aml_opcode) {
583 			case AML_NAME_OP:
584 				/*
585 				 * Put the Node on the object stack (Contains the ACPI Name
586 				 * of this object)
587 				 */
588 				walk_state->operands[0] = (void *)
589 				    op->common.parent->common.node;
590 				walk_state->num_operands = 1;
591 
592 				status = acpi_ds_create_node(walk_state,
593 							     op->common.parent->
594 							     common.node,
595 							     op->common.parent);
596 				if (ACPI_FAILURE(status)) {
597 					break;
598 				}
599 
600 				ACPI_FALLTHROUGH;
601 
602 			case AML_INT_EVAL_SUBTREE_OP:
603 
604 				status =
605 				    acpi_ds_eval_data_object_operands
606 				    (walk_state, op,
607 				     acpi_ns_get_attached_object(op->common.
608 								 parent->common.
609 								 node));
610 				break;
611 
612 			default:
613 
614 				status =
615 				    acpi_ds_eval_data_object_operands
616 				    (walk_state, op, NULL);
617 				break;
618 			}
619 
620 			/*
621 			 * If a result object was returned from above, push it on the
622 			 * current result stack
623 			 */
624 			if (walk_state->result_obj) {
625 				status =
626 				    acpi_ds_result_push(walk_state->result_obj,
627 							walk_state);
628 			}
629 			break;
630 
631 		case AML_TYPE_NAMED_FIELD:
632 		case AML_TYPE_NAMED_COMPLEX:
633 		case AML_TYPE_NAMED_SIMPLE:
634 		case AML_TYPE_NAMED_NO_OBJ:
635 
636 			status = acpi_ds_load2_end_op(walk_state);
637 			if (ACPI_FAILURE(status)) {
638 				break;
639 			}
640 
641 			if (op->common.aml_opcode == AML_REGION_OP) {
642 				ACPI_DEBUG_PRINT((ACPI_DB_EXEC,
643 						  "Executing OpRegion Address/Length Op=%p\n",
644 						  op));
645 
646 				status =
647 				    acpi_ds_eval_region_operands(walk_state,
648 								 op);
649 				if (ACPI_FAILURE(status)) {
650 					break;
651 				}
652 			} else if (op->common.aml_opcode == AML_DATA_REGION_OP) {
653 				ACPI_DEBUG_PRINT((ACPI_DB_EXEC,
654 						  "Executing DataTableRegion Strings Op=%p\n",
655 						  op));
656 
657 				status =
658 				    acpi_ds_eval_table_region_operands
659 				    (walk_state, op);
660 				if (ACPI_FAILURE(status)) {
661 					break;
662 				}
663 			} else if (op->common.aml_opcode == AML_BANK_FIELD_OP) {
664 				ACPI_DEBUG_PRINT((ACPI_DB_EXEC,
665 						  "Executing BankField Op=%p\n",
666 						  op));
667 
668 				status =
669 				    acpi_ds_eval_bank_field_operands(walk_state,
670 								     op);
671 				if (ACPI_FAILURE(status)) {
672 					break;
673 				}
674 			}
675 			break;
676 
677 		case AML_TYPE_UNDEFINED:
678 
679 			ACPI_ERROR((AE_INFO,
680 				    "Undefined opcode type Op=%p", op));
681 			return_ACPI_STATUS(AE_NOT_IMPLEMENTED);
682 
683 		case AML_TYPE_BOGUS:
684 
685 			ACPI_DEBUG_PRINT((ACPI_DB_DISPATCH,
686 					  "Internal opcode=%X type Op=%p\n",
687 					  walk_state->opcode, op));
688 			break;
689 
690 		default:
691 
692 			ACPI_ERROR((AE_INFO,
693 				    "Unimplemented opcode, class=0x%X "
694 				    "type=0x%X Opcode=0x%X Op=%p",
695 				    op_class, op_type, op->common.aml_opcode,
696 				    op));
697 
698 			status = AE_NOT_IMPLEMENTED;
699 			break;
700 		}
701 	}
702 
703 	/*
704 	 * ACPI 2.0 support for 64-bit integers: Truncate numeric
705 	 * result value if we are executing from a 32-bit ACPI table
706 	 */
707 	(void)acpi_ex_truncate_for32bit_table(walk_state->result_obj);
708 
709 	/*
710 	 * Check if we just completed the evaluation of a
711 	 * conditional predicate
712 	 */
713 	if ((ACPI_SUCCESS(status)) &&
714 	    (walk_state->control_state) &&
715 	    (walk_state->control_state->common.state ==
716 	     ACPI_CONTROL_PREDICATE_EXECUTING) &&
717 	    (walk_state->control_state->control.predicate_op == op)) {
718 		status =
719 		    acpi_ds_get_predicate_value(walk_state,
720 						walk_state->result_obj);
721 		walk_state->result_obj = NULL;
722 	}
723 
724 cleanup:
725 
726 	if (walk_state->result_obj) {
727 
728 		/* Break to debugger to display result */
729 
730 		acpi_db_display_result_object(walk_state->result_obj,
731 					      walk_state);
732 
733 		/*
734 		 * Delete the result op if and only if:
735 		 * Parent will not use the result -- such as any
736 		 * non-nested type2 op in a method (parent will be method)
737 		 */
738 		acpi_ds_delete_result_if_not_used(op, walk_state->result_obj,
739 						  walk_state);
740 	}
741 #ifdef _UNDER_DEVELOPMENT
742 
743 	if (walk_state->parser_state.aml == walk_state->parser_state.aml_end) {
744 		acpi_db_method_end(walk_state);
745 	}
746 #endif
747 
748 	/* Invoke exception handler on error */
749 
750 	if (ACPI_FAILURE(status)) {
751 		status = acpi_ds_method_error(status, walk_state);
752 	}
753 
754 	/* Always clear the object stack */
755 
756 	walk_state->num_operands = 0;
757 	return_ACPI_STATUS(status);
758 }
759