xref: /openbmc/linux/drivers/acpi/acpica/exresop.c (revision a06c488d)
1 /******************************************************************************
2  *
3  * Module Name: exresop - AML Interpreter operand/object resolution
4  *
5  *****************************************************************************/
6 
7 /*
8  * Copyright (C) 2000 - 2016, 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 "amlcode.h"
47 #include "acparser.h"
48 #include "acinterp.h"
49 #include "acnamesp.h"
50 
51 #define _COMPONENT          ACPI_EXECUTER
52 ACPI_MODULE_NAME("exresop")
53 
54 /* Local prototypes */
55 static acpi_status
56 acpi_ex_check_object_type(acpi_object_type type_needed,
57 			  acpi_object_type this_type, void *object);
58 
59 /*******************************************************************************
60  *
61  * FUNCTION:    acpi_ex_check_object_type
62  *
63  * PARAMETERS:  type_needed         Object type needed
64  *              this_type           Actual object type
65  *              Object              Object pointer
66  *
67  * RETURN:      Status
68  *
69  * DESCRIPTION: Check required type against actual type
70  *
71  ******************************************************************************/
72 
73 static acpi_status
74 acpi_ex_check_object_type(acpi_object_type type_needed,
75 			  acpi_object_type this_type, void *object)
76 {
77 	ACPI_FUNCTION_ENTRY();
78 
79 	if (type_needed == ACPI_TYPE_ANY) {
80 
81 		/* All types OK, so we don't perform any typechecks */
82 
83 		return (AE_OK);
84 	}
85 
86 	if (type_needed == ACPI_TYPE_LOCAL_REFERENCE) {
87 		/*
88 		 * Allow the AML "Constant" opcodes (Zero, One, etc.) to be reference
89 		 * objects and thus allow them to be targets. (As per the ACPI
90 		 * specification, a store to a constant is a noop.)
91 		 */
92 		if ((this_type == ACPI_TYPE_INTEGER) &&
93 		    (((union acpi_operand_object *)object)->common.flags &
94 		     AOPOBJ_AML_CONSTANT)) {
95 			return (AE_OK);
96 		}
97 	}
98 
99 	if (type_needed != this_type) {
100 		ACPI_ERROR((AE_INFO,
101 			    "Needed type [%s], found [%s] %p",
102 			    acpi_ut_get_type_name(type_needed),
103 			    acpi_ut_get_type_name(this_type), object));
104 
105 		return (AE_AML_OPERAND_TYPE);
106 	}
107 
108 	return (AE_OK);
109 }
110 
111 /*******************************************************************************
112  *
113  * FUNCTION:    acpi_ex_resolve_operands
114  *
115  * PARAMETERS:  opcode              - Opcode being interpreted
116  *              stack_ptr           - Pointer to the operand stack to be
117  *                                    resolved
118  *              walk_state          - Current state
119  *
120  * RETURN:      Status
121  *
122  * DESCRIPTION: Convert multiple input operands to the types required by the
123  *              target operator.
124  *
125  *      Each 5-bit group in arg_types represents one required
126  *      operand and indicates the required Type. The corresponding operand
127  *      will be converted to the required type if possible, otherwise we
128  *      abort with an exception.
129  *
130  ******************************************************************************/
131 
132 acpi_status
133 acpi_ex_resolve_operands(u16 opcode,
134 			 union acpi_operand_object ** stack_ptr,
135 			 struct acpi_walk_state * walk_state)
136 {
137 	union acpi_operand_object *obj_desc;
138 	acpi_status status = AE_OK;
139 	u8 object_type;
140 	u32 arg_types;
141 	const struct acpi_opcode_info *op_info;
142 	u32 this_arg_type;
143 	acpi_object_type type_needed;
144 	u16 target_op = 0;
145 
146 	ACPI_FUNCTION_TRACE_U32(ex_resolve_operands, opcode);
147 
148 	op_info = acpi_ps_get_opcode_info(opcode);
149 	if (op_info->class == AML_CLASS_UNKNOWN) {
150 		return_ACPI_STATUS(AE_AML_BAD_OPCODE);
151 	}
152 
153 	arg_types = op_info->runtime_args;
154 	if (arg_types == ARGI_INVALID_OPCODE) {
155 		ACPI_ERROR((AE_INFO, "Unknown AML opcode 0x%X", opcode));
156 
157 		return_ACPI_STATUS(AE_AML_INTERNAL);
158 	}
159 
160 	ACPI_DEBUG_PRINT((ACPI_DB_EXEC,
161 			  "Opcode %X [%s] RequiredOperandTypes=%8.8X\n",
162 			  opcode, op_info->name, arg_types));
163 
164 	/*
165 	 * Normal exit is with (arg_types == 0) at end of argument list.
166 	 * Function will return an exception from within the loop upon
167 	 * finding an entry which is not (or cannot be converted
168 	 * to) the required type; if stack underflows; or upon
169 	 * finding a NULL stack entry (which should not happen).
170 	 */
171 	while (GET_CURRENT_ARG_TYPE(arg_types)) {
172 		if (!stack_ptr || !*stack_ptr) {
173 			ACPI_ERROR((AE_INFO, "Null stack entry at %p",
174 				    stack_ptr));
175 
176 			return_ACPI_STATUS(AE_AML_INTERNAL);
177 		}
178 
179 		/* Extract useful items */
180 
181 		obj_desc = *stack_ptr;
182 
183 		/* Decode the descriptor type */
184 
185 		switch (ACPI_GET_DESCRIPTOR_TYPE(obj_desc)) {
186 		case ACPI_DESC_TYPE_NAMED:
187 
188 			/* Namespace Node */
189 
190 			object_type =
191 			    ((struct acpi_namespace_node *)obj_desc)->type;
192 
193 			/*
194 			 * Resolve an alias object. The construction of these objects
195 			 * guarantees that there is only one level of alias indirection;
196 			 * thus, the attached object is always the aliased namespace node
197 			 */
198 			if (object_type == ACPI_TYPE_LOCAL_ALIAS) {
199 				obj_desc = acpi_ns_get_attached_object((struct
200 									acpi_namespace_node
201 									*)
202 								       obj_desc);
203 				*stack_ptr = obj_desc;
204 				object_type =
205 				    ((struct acpi_namespace_node *)obj_desc)->
206 				    type;
207 			}
208 			break;
209 
210 		case ACPI_DESC_TYPE_OPERAND:
211 
212 			/* ACPI internal object */
213 
214 			object_type = obj_desc->common.type;
215 
216 			/* Check for bad acpi_object_type */
217 
218 			if (!acpi_ut_valid_object_type(object_type)) {
219 				ACPI_ERROR((AE_INFO,
220 					    "Bad operand object type [0x%X]",
221 					    object_type));
222 
223 				return_ACPI_STATUS(AE_AML_OPERAND_TYPE);
224 			}
225 
226 			if (object_type == (u8) ACPI_TYPE_LOCAL_REFERENCE) {
227 
228 				/* Validate the Reference */
229 
230 				switch (obj_desc->reference.class) {
231 				case ACPI_REFCLASS_DEBUG:
232 
233 					target_op = AML_DEBUG_OP;
234 
235 					/*lint -fallthrough */
236 
237 				case ACPI_REFCLASS_ARG:
238 				case ACPI_REFCLASS_LOCAL:
239 				case ACPI_REFCLASS_INDEX:
240 				case ACPI_REFCLASS_REFOF:
241 				case ACPI_REFCLASS_TABLE:	/* ddb_handle from LOAD_OP or LOAD_TABLE_OP */
242 				case ACPI_REFCLASS_NAME:	/* Reference to a named object */
243 
244 					ACPI_DEBUG_PRINT((ACPI_DB_EXEC,
245 							  "Operand is a Reference, Class [%s] %2.2X\n",
246 							  acpi_ut_get_reference_name
247 							  (obj_desc),
248 							  obj_desc->reference.
249 							  class));
250 					break;
251 
252 				default:
253 
254 					ACPI_ERROR((AE_INFO,
255 						    "Unknown Reference Class 0x%2.2X in %p",
256 						    obj_desc->reference.class,
257 						    obj_desc));
258 
259 					return_ACPI_STATUS(AE_AML_OPERAND_TYPE);
260 				}
261 			}
262 			break;
263 
264 		default:
265 
266 			/* Invalid descriptor */
267 
268 			ACPI_ERROR((AE_INFO, "Invalid descriptor %p [%s]",
269 				    obj_desc,
270 				    acpi_ut_get_descriptor_name(obj_desc)));
271 
272 			return_ACPI_STATUS(AE_AML_OPERAND_TYPE);
273 		}
274 
275 		/* Get one argument type, point to the next */
276 
277 		this_arg_type = GET_CURRENT_ARG_TYPE(arg_types);
278 		INCREMENT_ARG_LIST(arg_types);
279 
280 		/*
281 		 * Handle cases where the object does not need to be
282 		 * resolved to a value
283 		 */
284 		switch (this_arg_type) {
285 		case ARGI_REF_OR_STRING:	/* Can be a String or Reference */
286 
287 			if ((ACPI_GET_DESCRIPTOR_TYPE(obj_desc) ==
288 			     ACPI_DESC_TYPE_OPERAND) &&
289 			    (obj_desc->common.type == ACPI_TYPE_STRING)) {
290 				/*
291 				 * String found - the string references a named object and
292 				 * must be resolved to a node
293 				 */
294 				goto next_operand;
295 			}
296 
297 			/*
298 			 * Else not a string - fall through to the normal Reference
299 			 * case below
300 			 */
301 			/*lint -fallthrough */
302 
303 		case ARGI_REFERENCE:	/* References: */
304 		case ARGI_INTEGER_REF:
305 		case ARGI_OBJECT_REF:
306 		case ARGI_DEVICE_REF:
307 		case ARGI_TARGETREF:	/* Allows implicit conversion rules before store */
308 		case ARGI_FIXED_TARGET:	/* No implicit conversion before store to target */
309 		case ARGI_SIMPLE_TARGET:	/* Name, Local, or arg - no implicit conversion  */
310 		case ARGI_STORE_TARGET:
311 
312 			/*
313 			 * Need an operand of type ACPI_TYPE_LOCAL_REFERENCE
314 			 * A Namespace Node is OK as-is
315 			 */
316 			if (ACPI_GET_DESCRIPTOR_TYPE(obj_desc) ==
317 			    ACPI_DESC_TYPE_NAMED) {
318 				goto next_operand;
319 			}
320 
321 			status =
322 			    acpi_ex_check_object_type(ACPI_TYPE_LOCAL_REFERENCE,
323 						      object_type, obj_desc);
324 			if (ACPI_FAILURE(status)) {
325 				return_ACPI_STATUS(status);
326 			}
327 			goto next_operand;
328 
329 		case ARGI_DATAREFOBJ:	/* Store operator only */
330 			/*
331 			 * We don't want to resolve index_op reference objects during
332 			 * a store because this would be an implicit de_ref_of operation.
333 			 * Instead, we just want to store the reference object.
334 			 * -- All others must be resolved below.
335 			 */
336 			if ((opcode == AML_STORE_OP) &&
337 			    ((*stack_ptr)->common.type ==
338 			     ACPI_TYPE_LOCAL_REFERENCE)
339 			    && ((*stack_ptr)->reference.class ==
340 				ACPI_REFCLASS_INDEX)) {
341 				goto next_operand;
342 			}
343 			break;
344 
345 		default:
346 
347 			/* All cases covered above */
348 
349 			break;
350 		}
351 
352 		/*
353 		 * Resolve this object to a value
354 		 */
355 		status = acpi_ex_resolve_to_value(stack_ptr, walk_state);
356 		if (ACPI_FAILURE(status)) {
357 			return_ACPI_STATUS(status);
358 		}
359 
360 		/* Get the resolved object */
361 
362 		obj_desc = *stack_ptr;
363 
364 		/*
365 		 * Check the resulting object (value) type
366 		 */
367 		switch (this_arg_type) {
368 			/*
369 			 * For the simple cases, only one type of resolved object
370 			 * is allowed
371 			 */
372 		case ARGI_MUTEX:
373 
374 			/* Need an operand of type ACPI_TYPE_MUTEX */
375 
376 			type_needed = ACPI_TYPE_MUTEX;
377 			break;
378 
379 		case ARGI_EVENT:
380 
381 			/* Need an operand of type ACPI_TYPE_EVENT */
382 
383 			type_needed = ACPI_TYPE_EVENT;
384 			break;
385 
386 		case ARGI_PACKAGE:	/* Package */
387 
388 			/* Need an operand of type ACPI_TYPE_PACKAGE */
389 
390 			type_needed = ACPI_TYPE_PACKAGE;
391 			break;
392 
393 		case ARGI_ANYTYPE:
394 
395 			/* Any operand type will do */
396 
397 			type_needed = ACPI_TYPE_ANY;
398 			break;
399 
400 		case ARGI_DDBHANDLE:
401 
402 			/* Need an operand of type ACPI_TYPE_DDB_HANDLE */
403 
404 			type_needed = ACPI_TYPE_LOCAL_REFERENCE;
405 			break;
406 
407 			/*
408 			 * The more complex cases allow multiple resolved object types
409 			 */
410 		case ARGI_INTEGER:
411 
412 			/*
413 			 * Need an operand of type ACPI_TYPE_INTEGER,
414 			 * But we can implicitly convert from a STRING or BUFFER
415 			 * aka - "Implicit Source Operand Conversion"
416 			 */
417 			status =
418 			    acpi_ex_convert_to_integer(obj_desc, stack_ptr, 16);
419 			if (ACPI_FAILURE(status)) {
420 				if (status == AE_TYPE) {
421 					ACPI_ERROR((AE_INFO,
422 						    "Needed [Integer/String/Buffer], found [%s] %p",
423 						    acpi_ut_get_object_type_name
424 						    (obj_desc), obj_desc));
425 
426 					return_ACPI_STATUS(AE_AML_OPERAND_TYPE);
427 				}
428 
429 				return_ACPI_STATUS(status);
430 			}
431 
432 			if (obj_desc != *stack_ptr) {
433 				acpi_ut_remove_reference(obj_desc);
434 			}
435 			goto next_operand;
436 
437 		case ARGI_BUFFER:
438 			/*
439 			 * Need an operand of type ACPI_TYPE_BUFFER,
440 			 * But we can implicitly convert from a STRING or INTEGER
441 			 * aka - "Implicit Source Operand Conversion"
442 			 */
443 			status = acpi_ex_convert_to_buffer(obj_desc, stack_ptr);
444 			if (ACPI_FAILURE(status)) {
445 				if (status == AE_TYPE) {
446 					ACPI_ERROR((AE_INFO,
447 						    "Needed [Integer/String/Buffer], found [%s] %p",
448 						    acpi_ut_get_object_type_name
449 						    (obj_desc), obj_desc));
450 
451 					return_ACPI_STATUS(AE_AML_OPERAND_TYPE);
452 				}
453 
454 				return_ACPI_STATUS(status);
455 			}
456 
457 			if (obj_desc != *stack_ptr) {
458 				acpi_ut_remove_reference(obj_desc);
459 			}
460 			goto next_operand;
461 
462 		case ARGI_STRING:
463 			/*
464 			 * Need an operand of type ACPI_TYPE_STRING,
465 			 * But we can implicitly convert from a BUFFER or INTEGER
466 			 * aka - "Implicit Source Operand Conversion"
467 			 */
468 			status =
469 			    acpi_ex_convert_to_string(obj_desc, stack_ptr,
470 						      ACPI_IMPLICIT_CONVERT_HEX);
471 			if (ACPI_FAILURE(status)) {
472 				if (status == AE_TYPE) {
473 					ACPI_ERROR((AE_INFO,
474 						    "Needed [Integer/String/Buffer], found [%s] %p",
475 						    acpi_ut_get_object_type_name
476 						    (obj_desc), obj_desc));
477 
478 					return_ACPI_STATUS(AE_AML_OPERAND_TYPE);
479 				}
480 
481 				return_ACPI_STATUS(status);
482 			}
483 
484 			if (obj_desc != *stack_ptr) {
485 				acpi_ut_remove_reference(obj_desc);
486 			}
487 			goto next_operand;
488 
489 		case ARGI_COMPUTEDATA:
490 
491 			/* Need an operand of type INTEGER, STRING or BUFFER */
492 
493 			switch (obj_desc->common.type) {
494 			case ACPI_TYPE_INTEGER:
495 			case ACPI_TYPE_STRING:
496 			case ACPI_TYPE_BUFFER:
497 
498 				/* Valid operand */
499 				break;
500 
501 			default:
502 				ACPI_ERROR((AE_INFO,
503 					    "Needed [Integer/String/Buffer], found [%s] %p",
504 					    acpi_ut_get_object_type_name
505 					    (obj_desc), obj_desc));
506 
507 				return_ACPI_STATUS(AE_AML_OPERAND_TYPE);
508 			}
509 			goto next_operand;
510 
511 		case ARGI_BUFFER_OR_STRING:
512 
513 			/* Need an operand of type STRING or BUFFER */
514 
515 			switch (obj_desc->common.type) {
516 			case ACPI_TYPE_STRING:
517 			case ACPI_TYPE_BUFFER:
518 
519 				/* Valid operand */
520 				break;
521 
522 			case ACPI_TYPE_INTEGER:
523 
524 				/* Highest priority conversion is to type Buffer */
525 
526 				status =
527 				    acpi_ex_convert_to_buffer(obj_desc,
528 							      stack_ptr);
529 				if (ACPI_FAILURE(status)) {
530 					return_ACPI_STATUS(status);
531 				}
532 
533 				if (obj_desc != *stack_ptr) {
534 					acpi_ut_remove_reference(obj_desc);
535 				}
536 				break;
537 
538 			default:
539 				ACPI_ERROR((AE_INFO,
540 					    "Needed [Integer/String/Buffer], found [%s] %p",
541 					    acpi_ut_get_object_type_name
542 					    (obj_desc), obj_desc));
543 
544 				return_ACPI_STATUS(AE_AML_OPERAND_TYPE);
545 			}
546 			goto next_operand;
547 
548 		case ARGI_DATAOBJECT:
549 			/*
550 			 * ARGI_DATAOBJECT is only used by the size_of operator.
551 			 * Need a buffer, string, package, or ref_of reference.
552 			 *
553 			 * The only reference allowed here is a direct reference to
554 			 * a namespace node.
555 			 */
556 			switch (obj_desc->common.type) {
557 			case ACPI_TYPE_PACKAGE:
558 			case ACPI_TYPE_STRING:
559 			case ACPI_TYPE_BUFFER:
560 			case ACPI_TYPE_LOCAL_REFERENCE:
561 
562 				/* Valid operand */
563 				break;
564 
565 			default:
566 
567 				ACPI_ERROR((AE_INFO,
568 					    "Needed [Buffer/String/Package/Reference], found [%s] %p",
569 					    acpi_ut_get_object_type_name
570 					    (obj_desc), obj_desc));
571 
572 				return_ACPI_STATUS(AE_AML_OPERAND_TYPE);
573 			}
574 			goto next_operand;
575 
576 		case ARGI_COMPLEXOBJ:
577 
578 			/* Need a buffer or package or (ACPI 2.0) String */
579 
580 			switch (obj_desc->common.type) {
581 			case ACPI_TYPE_PACKAGE:
582 			case ACPI_TYPE_STRING:
583 			case ACPI_TYPE_BUFFER:
584 
585 				/* Valid operand */
586 				break;
587 
588 			default:
589 
590 				ACPI_ERROR((AE_INFO,
591 					    "Needed [Buffer/String/Package], found [%s] %p",
592 					    acpi_ut_get_object_type_name
593 					    (obj_desc), obj_desc));
594 
595 				return_ACPI_STATUS(AE_AML_OPERAND_TYPE);
596 			}
597 			goto next_operand;
598 
599 		case ARGI_REGION_OR_BUFFER:	/* Used by Load() only */
600 
601 			/*
602 			 * Need an operand of type REGION or a BUFFER
603 			 * (which could be a resolved region field)
604 			 */
605 			switch (obj_desc->common.type) {
606 			case ACPI_TYPE_BUFFER:
607 			case ACPI_TYPE_REGION:
608 
609 				/* Valid operand */
610 				break;
611 
612 			default:
613 
614 				ACPI_ERROR((AE_INFO,
615 					    "Needed [Region/Buffer], found [%s] %p",
616 					    acpi_ut_get_object_type_name
617 					    (obj_desc), obj_desc));
618 
619 				return_ACPI_STATUS(AE_AML_OPERAND_TYPE);
620 			}
621 			goto next_operand;
622 
623 		case ARGI_DATAREFOBJ:
624 
625 			/* Used by the Store() operator only */
626 
627 			switch (obj_desc->common.type) {
628 			case ACPI_TYPE_INTEGER:
629 			case ACPI_TYPE_PACKAGE:
630 			case ACPI_TYPE_STRING:
631 			case ACPI_TYPE_BUFFER:
632 			case ACPI_TYPE_BUFFER_FIELD:
633 			case ACPI_TYPE_LOCAL_REFERENCE:
634 			case ACPI_TYPE_LOCAL_REGION_FIELD:
635 			case ACPI_TYPE_LOCAL_BANK_FIELD:
636 			case ACPI_TYPE_LOCAL_INDEX_FIELD:
637 			case ACPI_TYPE_DDB_HANDLE:
638 
639 				/* Valid operand */
640 				break;
641 
642 			default:
643 
644 				if (acpi_gbl_enable_interpreter_slack) {
645 					/*
646 					 * Enable original behavior of Store(), allowing any
647 					 * and all objects as the source operand. The ACPI
648 					 * spec does not allow this, however.
649 					 */
650 					break;
651 				}
652 
653 				if (target_op == AML_DEBUG_OP) {
654 
655 					/* Allow store of any object to the Debug object */
656 
657 					break;
658 				}
659 
660 				ACPI_ERROR((AE_INFO,
661 					    "Needed Integer/Buffer/String/Package/Ref/Ddb]"
662 					    ", found [%s] %p",
663 					    acpi_ut_get_object_type_name
664 					    (obj_desc), obj_desc));
665 
666 				return_ACPI_STATUS(AE_AML_OPERAND_TYPE);
667 			}
668 			goto next_operand;
669 
670 		default:
671 
672 			/* Unknown type */
673 
674 			ACPI_ERROR((AE_INFO,
675 				    "Internal - Unknown ARGI (required operand) type 0x%X",
676 				    this_arg_type));
677 
678 			return_ACPI_STATUS(AE_BAD_PARAMETER);
679 		}
680 
681 		/*
682 		 * Make sure that the original object was resolved to the
683 		 * required object type (Simple cases only).
684 		 */
685 		status =
686 		    acpi_ex_check_object_type(type_needed,
687 					      (*stack_ptr)->common.type,
688 					      *stack_ptr);
689 		if (ACPI_FAILURE(status)) {
690 			return_ACPI_STATUS(status);
691 		}
692 
693 next_operand:
694 		/*
695 		 * If more operands needed, decrement stack_ptr to point
696 		 * to next operand on stack
697 		 */
698 		if (GET_CURRENT_ARG_TYPE(arg_types)) {
699 			stack_ptr--;
700 		}
701 	}
702 
703 	ACPI_DUMP_OPERANDS(walk_state->operands,
704 			   acpi_ps_get_opcode_name(opcode),
705 			   walk_state->num_operands);
706 
707 	return_ACPI_STATUS(status);
708 }
709