xref: /openbmc/linux/drivers/acpi/acpica/exoparg1.c (revision 53a2a90d)
1 // SPDX-License-Identifier: BSD-3-Clause OR GPL-2.0
2 /******************************************************************************
3  *
4  * Module Name: exoparg1 - AML execution - opcodes with 1 argument
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 "acdispat.h"
14 #include "acinterp.h"
15 #include "amlcode.h"
16 #include "acnamesp.h"
17 
18 #define _COMPONENT          ACPI_EXECUTER
19 ACPI_MODULE_NAME("exoparg1")
20 
21 /*!
22  * Naming convention for AML interpreter execution routines.
23  *
24  * The routines that begin execution of AML opcodes are named with a common
25  * convention based upon the number of arguments, the number of target operands,
26  * and whether or not a value is returned:
27  *
28  *      AcpiExOpcode_xA_yT_zR
29  *
30  * Where:
31  *
32  * xA - ARGUMENTS:    The number of arguments (input operands) that are
33  *                    required for this opcode type (0 through 6 args).
34  * yT - TARGETS:      The number of targets (output operands) that are required
35  *                    for this opcode type (0, 1, or 2 targets).
36  * zR - RETURN VALUE: Indicates whether this opcode type returns a value
37  *                    as the function return (0 or 1).
38  *
39  * The AcpiExOpcode* functions are called via the Dispatcher component with
40  * fully resolved operands.
41 !*/
42 /*******************************************************************************
43  *
44  * FUNCTION:    acpi_ex_opcode_0A_0T_1R
45  *
46  * PARAMETERS:  walk_state          - Current state (contains AML opcode)
47  *
48  * RETURN:      Status
49  *
50  * DESCRIPTION: Execute operator with no operands, one return value
51  *
52  ******************************************************************************/
53 acpi_status acpi_ex_opcode_0A_0T_1R(struct acpi_walk_state *walk_state)
54 {
55 	acpi_status status = AE_OK;
56 	union acpi_operand_object *return_desc = NULL;
57 
58 	ACPI_FUNCTION_TRACE_STR(ex_opcode_0A_0T_1R,
59 				acpi_ps_get_opcode_name(walk_state->opcode));
60 
61 	/* Examine the AML opcode */
62 
63 	switch (walk_state->opcode) {
64 	case AML_TIMER_OP:	/*  Timer () */
65 
66 		/* Create a return object of type Integer */
67 
68 		return_desc =
69 		    acpi_ut_create_integer_object(acpi_os_get_timer());
70 		if (!return_desc) {
71 			status = AE_NO_MEMORY;
72 			goto cleanup;
73 		}
74 		break;
75 
76 	default:		/*  Unknown opcode  */
77 
78 		ACPI_ERROR((AE_INFO, "Unknown AML opcode 0x%X",
79 			    walk_state->opcode));
80 		status = AE_AML_BAD_OPCODE;
81 		break;
82 	}
83 
84 cleanup:
85 
86 	/* Delete return object on error */
87 
88 	if ((ACPI_FAILURE(status)) || walk_state->result_obj) {
89 		acpi_ut_remove_reference(return_desc);
90 		walk_state->result_obj = NULL;
91 	} else {
92 		/* Save the return value */
93 
94 		walk_state->result_obj = return_desc;
95 	}
96 
97 	return_ACPI_STATUS(status);
98 }
99 
100 /*******************************************************************************
101  *
102  * FUNCTION:    acpi_ex_opcode_1A_0T_0R
103  *
104  * PARAMETERS:  walk_state          - Current state (contains AML opcode)
105  *
106  * RETURN:      Status
107  *
108  * DESCRIPTION: Execute Type 1 monadic operator with numeric operand on
109  *              object stack
110  *
111  ******************************************************************************/
112 
113 acpi_status acpi_ex_opcode_1A_0T_0R(struct acpi_walk_state *walk_state)
114 {
115 	union acpi_operand_object **operand = &walk_state->operands[0];
116 	acpi_status status = AE_OK;
117 
118 	ACPI_FUNCTION_TRACE_STR(ex_opcode_1A_0T_0R,
119 				acpi_ps_get_opcode_name(walk_state->opcode));
120 
121 	/* Examine the AML opcode */
122 
123 	switch (walk_state->opcode) {
124 	case AML_RELEASE_OP:	/*  Release (mutex_object) */
125 
126 		status = acpi_ex_release_mutex(operand[0], walk_state);
127 		break;
128 
129 	case AML_RESET_OP:	/*  Reset (event_object) */
130 
131 		status = acpi_ex_system_reset_event(operand[0]);
132 		break;
133 
134 	case AML_SIGNAL_OP:	/*  Signal (event_object) */
135 
136 		status = acpi_ex_system_signal_event(operand[0]);
137 		break;
138 
139 	case AML_SLEEP_OP:	/*  Sleep (msec_time) */
140 
141 		status = acpi_ex_system_do_sleep(operand[0]->integer.value);
142 		break;
143 
144 	case AML_STALL_OP:	/*  Stall (usec_time) */
145 
146 		status =
147 		    acpi_ex_system_do_stall((u32) operand[0]->integer.value);
148 		break;
149 
150 	case AML_UNLOAD_OP:	/*  Unload (Handle) */
151 
152 		status = acpi_ex_unload_table(operand[0]);
153 		break;
154 
155 	default:		/*  Unknown opcode  */
156 
157 		ACPI_ERROR((AE_INFO, "Unknown AML opcode 0x%X",
158 			    walk_state->opcode));
159 		status = AE_AML_BAD_OPCODE;
160 		break;
161 	}
162 
163 	return_ACPI_STATUS(status);
164 }
165 
166 #ifdef _OBSOLETE_CODE		/* Was originally used for Load() operator */
167 /*******************************************************************************
168  *
169  * FUNCTION:    acpi_ex_opcode_1A_1T_0R
170  *
171  * PARAMETERS:  walk_state          - Current state (contains AML opcode)
172  *
173  * RETURN:      Status
174  *
175  * DESCRIPTION: Execute opcode with one argument, one target, and no
176  *              return value.
177  *
178  ******************************************************************************/
179 
180 acpi_status acpi_ex_opcode_1A_1T_0R(struct acpi_walk_state *walk_state)
181 {
182 	acpi_status status = AE_OK;
183 	union acpi_operand_object **operand = &walk_state->operands[0];
184 
185 	ACPI_FUNCTION_TRACE_STR(ex_opcode_1A_1T_0R,
186 				acpi_ps_get_opcode_name(walk_state->opcode));
187 
188 	/* Examine the AML opcode */
189 
190 	switch (walk_state->opcode) {
191 #ifdef _OBSOLETE_CODE
192 	case AML_LOAD_OP:
193 
194 		status = acpi_ex_load_op(operand[0], operand[1], walk_state);
195 		break;
196 #endif
197 
198 	default:		/* Unknown opcode */
199 
200 		ACPI_ERROR((AE_INFO, "Unknown AML opcode 0x%X",
201 			    walk_state->opcode));
202 		status = AE_AML_BAD_OPCODE;
203 		goto cleanup;
204 	}
205 
206 cleanup:
207 
208 	return_ACPI_STATUS(status);
209 }
210 #endif
211 
212 /*******************************************************************************
213  *
214  * FUNCTION:    acpi_ex_opcode_1A_1T_1R
215  *
216  * PARAMETERS:  walk_state          - Current state (contains AML opcode)
217  *
218  * RETURN:      Status
219  *
220  * DESCRIPTION: Execute opcode with one argument, one target, and a
221  *              return value.
222  *              January 2022: Added Load operator, with new ACPI 6.4
223  *              semantics.
224  *
225  ******************************************************************************/
226 
227 acpi_status acpi_ex_opcode_1A_1T_1R(struct acpi_walk_state *walk_state)
228 {
229 	acpi_status status = AE_OK;
230 	union acpi_operand_object **operand = &walk_state->operands[0];
231 	union acpi_operand_object *return_desc = NULL;
232 	union acpi_operand_object *return_desc2 = NULL;
233 	u32 temp32;
234 	u32 i;
235 	u64 power_of_ten;
236 	u64 digit;
237 
238 	ACPI_FUNCTION_TRACE_STR(ex_opcode_1A_1T_1R,
239 				acpi_ps_get_opcode_name(walk_state->opcode));
240 
241 	/* Examine the AML opcode */
242 
243 	switch (walk_state->opcode) {
244 	case AML_BIT_NOT_OP:
245 	case AML_FIND_SET_LEFT_BIT_OP:
246 	case AML_FIND_SET_RIGHT_BIT_OP:
247 	case AML_FROM_BCD_OP:
248 	case AML_LOAD_OP:
249 	case AML_TO_BCD_OP:
250 	case AML_CONDITIONAL_REF_OF_OP:
251 
252 		/* Create a return object of type Integer for these opcodes */
253 
254 		return_desc = acpi_ut_create_internal_object(ACPI_TYPE_INTEGER);
255 		if (!return_desc) {
256 			status = AE_NO_MEMORY;
257 			goto cleanup;
258 		}
259 
260 		switch (walk_state->opcode) {
261 		case AML_BIT_NOT_OP:	/* Not (Operand, Result)  */
262 
263 			return_desc->integer.value = ~operand[0]->integer.value;
264 			break;
265 
266 		case AML_FIND_SET_LEFT_BIT_OP:	/* find_set_left_bit (Operand, Result) */
267 
268 			return_desc->integer.value = operand[0]->integer.value;
269 
270 			/*
271 			 * Acpi specification describes Integer type as a little
272 			 * endian unsigned value, so this boundary condition is valid.
273 			 */
274 			for (temp32 = 0; return_desc->integer.value &&
275 			     temp32 < ACPI_INTEGER_BIT_SIZE; ++temp32) {
276 				return_desc->integer.value >>= 1;
277 			}
278 
279 			return_desc->integer.value = temp32;
280 			break;
281 
282 		case AML_FIND_SET_RIGHT_BIT_OP:	/* find_set_right_bit (Operand, Result) */
283 
284 			return_desc->integer.value = operand[0]->integer.value;
285 
286 			/*
287 			 * The Acpi specification describes Integer type as a little
288 			 * endian unsigned value, so this boundary condition is valid.
289 			 */
290 			for (temp32 = 0; return_desc->integer.value &&
291 			     temp32 < ACPI_INTEGER_BIT_SIZE; ++temp32) {
292 				return_desc->integer.value <<= 1;
293 			}
294 
295 			/* Since the bit position is one-based, subtract from 33 (65) */
296 
297 			return_desc->integer.value =
298 			    temp32 ==
299 			    0 ? 0 : (ACPI_INTEGER_BIT_SIZE + 1) - temp32;
300 			break;
301 
302 		case AML_FROM_BCD_OP:	/* from_bcd (BCDValue, Result) */
303 			/*
304 			 * The 64-bit ACPI integer can hold 16 4-bit BCD characters
305 			 * (if table is 32-bit, integer can hold 8 BCD characters)
306 			 * Convert each 4-bit BCD value
307 			 */
308 			power_of_ten = 1;
309 			return_desc->integer.value = 0;
310 			digit = operand[0]->integer.value;
311 
312 			/* Convert each BCD digit (each is one nybble wide) */
313 
314 			for (i = 0;
315 			     (i < acpi_gbl_integer_nybble_width) && (digit > 0);
316 			     i++) {
317 
318 				/* Get the least significant 4-bit BCD digit */
319 
320 				temp32 = ((u32) digit) & 0xF;
321 
322 				/* Check the range of the digit */
323 
324 				if (temp32 > 9) {
325 					ACPI_ERROR((AE_INFO,
326 						    "BCD digit too large (not decimal): 0x%X",
327 						    temp32));
328 
329 					status = AE_AML_NUMERIC_OVERFLOW;
330 					goto cleanup;
331 				}
332 
333 				/* Sum the digit into the result with the current power of 10 */
334 
335 				return_desc->integer.value +=
336 				    (((u64) temp32) * power_of_ten);
337 
338 				/* Shift to next BCD digit */
339 
340 				digit >>= 4;
341 
342 				/* Next power of 10 */
343 
344 				power_of_ten *= 10;
345 			}
346 			break;
347 
348 		case AML_LOAD_OP:	/* Result1 = Load (Operand[0], Result1) */
349 
350 			return_desc->integer.value = 0;
351 			status =
352 			    acpi_ex_load_op(operand[0], return_desc,
353 					    walk_state);
354 			if (ACPI_SUCCESS(status)) {
355 
356 				/* Return -1 (non-zero) indicates success */
357 
358 				return_desc->integer.value = 0xFFFFFFFFFFFFFFFF;
359 			}
360 			break;
361 
362 		case AML_TO_BCD_OP:	/* to_bcd (Operand, Result) */
363 
364 			return_desc->integer.value = 0;
365 			digit = operand[0]->integer.value;
366 
367 			/* Each BCD digit is one nybble wide */
368 
369 			for (i = 0;
370 			     (i < acpi_gbl_integer_nybble_width) && (digit > 0);
371 			     i++) {
372 				(void)acpi_ut_short_divide(digit, 10, &digit,
373 							   &temp32);
374 
375 				/*
376 				 * Insert the BCD digit that resides in the
377 				 * remainder from above
378 				 */
379 				return_desc->integer.value |=
380 				    (((u64) temp32) << ACPI_MUL_4(i));
381 			}
382 
383 			/* Overflow if there is any data left in Digit */
384 
385 			if (digit > 0) {
386 				ACPI_ERROR((AE_INFO,
387 					    "Integer too large to convert to BCD: 0x%8.8X%8.8X",
388 					    ACPI_FORMAT_UINT64(operand[0]->
389 							       integer.value)));
390 				status = AE_AML_NUMERIC_OVERFLOW;
391 				goto cleanup;
392 			}
393 			break;
394 
395 		case AML_CONDITIONAL_REF_OF_OP:	/* cond_ref_of (source_object, Result) */
396 			/*
397 			 * This op is a little strange because the internal return value is
398 			 * different than the return value stored in the result descriptor
399 			 * (There are really two return values)
400 			 */
401 			if ((struct acpi_namespace_node *)operand[0] ==
402 			    acpi_gbl_root_node) {
403 				/*
404 				 * This means that the object does not exist in the namespace,
405 				 * return FALSE
406 				 */
407 				return_desc->integer.value = 0;
408 				goto cleanup;
409 			}
410 
411 			/* Get the object reference, store it, and remove our reference */
412 
413 			status = acpi_ex_get_object_reference(operand[0],
414 							      &return_desc2,
415 							      walk_state);
416 			if (ACPI_FAILURE(status)) {
417 				goto cleanup;
418 			}
419 
420 			status =
421 			    acpi_ex_store(return_desc2, operand[1], walk_state);
422 			acpi_ut_remove_reference(return_desc2);
423 
424 			/* The object exists in the namespace, return TRUE */
425 
426 			return_desc->integer.value = ACPI_UINT64_MAX;
427 			goto cleanup;
428 
429 		default:
430 
431 			/* No other opcodes get here */
432 
433 			break;
434 		}
435 		break;
436 
437 	case AML_STORE_OP:	/* Store (Source, Target) */
438 		/*
439 		 * A store operand is typically a number, string, buffer or lvalue
440 		 * Be careful about deleting the source object,
441 		 * since the object itself may have been stored.
442 		 */
443 		status = acpi_ex_store(operand[0], operand[1], walk_state);
444 		if (ACPI_FAILURE(status)) {
445 			return_ACPI_STATUS(status);
446 		}
447 
448 		/* It is possible that the Store already produced a return object */
449 
450 		if (!walk_state->result_obj) {
451 			/*
452 			 * Normally, we would remove a reference on the Operand[0]
453 			 * parameter; But since it is being used as the internal return
454 			 * object (meaning we would normally increment it), the two
455 			 * cancel out, and we simply don't do anything.
456 			 */
457 			walk_state->result_obj = operand[0];
458 			walk_state->operands[0] = NULL;	/* Prevent deletion */
459 		}
460 		return_ACPI_STATUS(status);
461 
462 		/*
463 		 * ACPI 2.0 Opcodes
464 		 */
465 	case AML_COPY_OBJECT_OP:	/* copy_object (Source, Target) */
466 
467 		status =
468 		    acpi_ut_copy_iobject_to_iobject(operand[0], &return_desc,
469 						    walk_state);
470 		break;
471 
472 	case AML_TO_DECIMAL_STRING_OP:	/* to_decimal_string (Data, Result) */
473 
474 		status =
475 		    acpi_ex_convert_to_string(operand[0], &return_desc,
476 					      ACPI_EXPLICIT_CONVERT_DECIMAL);
477 		if (return_desc == operand[0]) {
478 
479 			/* No conversion performed, add ref to handle return value */
480 
481 			acpi_ut_add_reference(return_desc);
482 		}
483 		break;
484 
485 	case AML_TO_HEX_STRING_OP:	/* to_hex_string (Data, Result) */
486 
487 		status =
488 		    acpi_ex_convert_to_string(operand[0], &return_desc,
489 					      ACPI_EXPLICIT_CONVERT_HEX);
490 		if (return_desc == operand[0]) {
491 
492 			/* No conversion performed, add ref to handle return value */
493 
494 			acpi_ut_add_reference(return_desc);
495 		}
496 		break;
497 
498 	case AML_TO_BUFFER_OP:	/* to_buffer (Data, Result) */
499 
500 		status = acpi_ex_convert_to_buffer(operand[0], &return_desc);
501 		if (return_desc == operand[0]) {
502 
503 			/* No conversion performed, add ref to handle return value */
504 
505 			acpi_ut_add_reference(return_desc);
506 		}
507 		break;
508 
509 	case AML_TO_INTEGER_OP:	/* to_integer (Data, Result) */
510 
511 		/* Perform "explicit" conversion */
512 
513 		status =
514 		    acpi_ex_convert_to_integer(operand[0], &return_desc, 0);
515 		if (return_desc == operand[0]) {
516 
517 			/* No conversion performed, add ref to handle return value */
518 
519 			acpi_ut_add_reference(return_desc);
520 		}
521 		break;
522 
523 	case AML_SHIFT_LEFT_BIT_OP:	/* shift_left_bit (Source, bit_num) */
524 	case AML_SHIFT_RIGHT_BIT_OP:	/* shift_right_bit (Source, bit_num) */
525 
526 		/* These are two obsolete opcodes */
527 
528 		ACPI_ERROR((AE_INFO,
529 			    "%s is obsolete and not implemented",
530 			    acpi_ps_get_opcode_name(walk_state->opcode)));
531 		status = AE_SUPPORT;
532 		goto cleanup;
533 
534 	default:		/* Unknown opcode */
535 
536 		ACPI_ERROR((AE_INFO, "Unknown AML opcode 0x%X",
537 			    walk_state->opcode));
538 		status = AE_AML_BAD_OPCODE;
539 		goto cleanup;
540 	}
541 
542 	if (ACPI_SUCCESS(status)) {
543 
544 		/* Store the return value computed above into the target object */
545 
546 		status = acpi_ex_store(return_desc, operand[1], walk_state);
547 	}
548 
549 cleanup:
550 
551 	/* Delete return object on error */
552 
553 	if (ACPI_FAILURE(status)) {
554 		acpi_ut_remove_reference(return_desc);
555 	}
556 
557 	/* Save return object on success */
558 
559 	else if (!walk_state->result_obj) {
560 		walk_state->result_obj = return_desc;
561 	}
562 
563 	return_ACPI_STATUS(status);
564 }
565 
566 /*******************************************************************************
567  *
568  * FUNCTION:    acpi_ex_opcode_1A_0T_1R
569  *
570  * PARAMETERS:  walk_state          - Current state (contains AML opcode)
571  *
572  * RETURN:      Status
573  *
574  * DESCRIPTION: Execute opcode with one argument, no target, and a return value
575  *
576  ******************************************************************************/
577 
578 acpi_status acpi_ex_opcode_1A_0T_1R(struct acpi_walk_state *walk_state)
579 {
580 	union acpi_operand_object **operand = &walk_state->operands[0];
581 	union acpi_operand_object *temp_desc;
582 	union acpi_operand_object *return_desc = NULL;
583 	acpi_status status = AE_OK;
584 	u32 type;
585 	u64 value;
586 
587 	ACPI_FUNCTION_TRACE_STR(ex_opcode_1A_0T_1R,
588 				acpi_ps_get_opcode_name(walk_state->opcode));
589 
590 	/* Examine the AML opcode */
591 
592 	switch (walk_state->opcode) {
593 	case AML_LOGICAL_NOT_OP:	/* LNot (Operand) */
594 
595 		return_desc = acpi_ut_create_integer_object((u64) 0);
596 		if (!return_desc) {
597 			status = AE_NO_MEMORY;
598 			goto cleanup;
599 		}
600 
601 		/*
602 		 * Set result to ONES (TRUE) if Value == 0. Note:
603 		 * return_desc->Integer.Value is initially == 0 (FALSE) from above.
604 		 */
605 		if (!operand[0]->integer.value) {
606 			return_desc->integer.value = ACPI_UINT64_MAX;
607 		}
608 		break;
609 
610 	case AML_DECREMENT_OP:	/* Decrement (Operand)  */
611 	case AML_INCREMENT_OP:	/* Increment (Operand)  */
612 		/*
613 		 * Create a new integer. Can't just get the base integer and
614 		 * increment it because it may be an Arg or Field.
615 		 */
616 		return_desc = acpi_ut_create_internal_object(ACPI_TYPE_INTEGER);
617 		if (!return_desc) {
618 			status = AE_NO_MEMORY;
619 			goto cleanup;
620 		}
621 
622 		/*
623 		 * Since we are expecting a Reference operand, it can be either a
624 		 * NS Node or an internal object.
625 		 */
626 		temp_desc = operand[0];
627 		if (ACPI_GET_DESCRIPTOR_TYPE(temp_desc) ==
628 		    ACPI_DESC_TYPE_OPERAND) {
629 
630 			/* Internal reference object - prevent deletion */
631 
632 			acpi_ut_add_reference(temp_desc);
633 		}
634 
635 		/*
636 		 * Convert the Reference operand to an Integer (This removes a
637 		 * reference on the Operand[0] object)
638 		 *
639 		 * NOTE:  We use LNOT_OP here in order to force resolution of the
640 		 * reference operand to an actual integer.
641 		 */
642 		status = acpi_ex_resolve_operands(AML_LOGICAL_NOT_OP,
643 						  &temp_desc, walk_state);
644 		if (ACPI_FAILURE(status)) {
645 			ACPI_EXCEPTION((AE_INFO, status,
646 					"While resolving operands for [%s]",
647 					acpi_ps_get_opcode_name(walk_state->
648 								opcode)));
649 
650 			goto cleanup;
651 		}
652 
653 		/*
654 		 * temp_desc is now guaranteed to be an Integer object --
655 		 * Perform the actual increment or decrement
656 		 */
657 		if (walk_state->opcode == AML_INCREMENT_OP) {
658 			return_desc->integer.value =
659 			    temp_desc->integer.value + 1;
660 		} else {
661 			return_desc->integer.value =
662 			    temp_desc->integer.value - 1;
663 		}
664 
665 		/* Finished with this Integer object */
666 
667 		acpi_ut_remove_reference(temp_desc);
668 
669 		/*
670 		 * Store the result back (indirectly) through the original
671 		 * Reference object
672 		 */
673 		status = acpi_ex_store(return_desc, operand[0], walk_state);
674 		break;
675 
676 	case AML_OBJECT_TYPE_OP:	/* object_type (source_object) */
677 		/*
678 		 * Note: The operand is not resolved at this point because we want to
679 		 * get the associated object, not its value. For example, we don't
680 		 * want to resolve a field_unit to its value, we want the actual
681 		 * field_unit object.
682 		 */
683 
684 		/* Get the type of the base object */
685 
686 		status =
687 		    acpi_ex_resolve_multiple(walk_state, operand[0], &type,
688 					     NULL);
689 		if (ACPI_FAILURE(status)) {
690 			goto cleanup;
691 		}
692 
693 		/* Allocate a descriptor to hold the type. */
694 
695 		return_desc = acpi_ut_create_integer_object((u64) type);
696 		if (!return_desc) {
697 			status = AE_NO_MEMORY;
698 			goto cleanup;
699 		}
700 		break;
701 
702 	case AML_SIZE_OF_OP:	/* size_of (source_object) */
703 		/*
704 		 * Note: The operand is not resolved at this point because we want to
705 		 * get the associated object, not its value.
706 		 */
707 
708 		/* Get the base object */
709 
710 		status =
711 		    acpi_ex_resolve_multiple(walk_state, operand[0], &type,
712 					     &temp_desc);
713 		if (ACPI_FAILURE(status)) {
714 			goto cleanup;
715 		}
716 
717 		/*
718 		 * The type of the base object must be integer, buffer, string, or
719 		 * package. All others are not supported.
720 		 *
721 		 * NOTE: Integer is not specifically supported by the ACPI spec,
722 		 * but is supported implicitly via implicit operand conversion.
723 		 * rather than bother with conversion, we just use the byte width
724 		 * global (4 or 8 bytes).
725 		 */
726 		switch (type) {
727 		case ACPI_TYPE_INTEGER:
728 
729 			value = acpi_gbl_integer_byte_width;
730 			break;
731 
732 		case ACPI_TYPE_STRING:
733 
734 			value = temp_desc->string.length;
735 			break;
736 
737 		case ACPI_TYPE_BUFFER:
738 
739 			/* Buffer arguments may not be evaluated at this point */
740 
741 			status = acpi_ds_get_buffer_arguments(temp_desc);
742 			value = temp_desc->buffer.length;
743 			break;
744 
745 		case ACPI_TYPE_PACKAGE:
746 
747 			/* Package arguments may not be evaluated at this point */
748 
749 			status = acpi_ds_get_package_arguments(temp_desc);
750 			value = temp_desc->package.count;
751 			break;
752 
753 		default:
754 
755 			ACPI_ERROR((AE_INFO,
756 				    "Operand must be Buffer/Integer/String/Package"
757 				    " - found type %s",
758 				    acpi_ut_get_type_name(type)));
759 
760 			status = AE_AML_OPERAND_TYPE;
761 			goto cleanup;
762 		}
763 
764 		if (ACPI_FAILURE(status)) {
765 			goto cleanup;
766 		}
767 
768 		/*
769 		 * Now that we have the size of the object, create a result
770 		 * object to hold the value
771 		 */
772 		return_desc = acpi_ut_create_integer_object(value);
773 		if (!return_desc) {
774 			status = AE_NO_MEMORY;
775 			goto cleanup;
776 		}
777 		break;
778 
779 	case AML_REF_OF_OP:	/* ref_of (source_object) */
780 
781 		status =
782 		    acpi_ex_get_object_reference(operand[0], &return_desc,
783 						 walk_state);
784 		if (ACPI_FAILURE(status)) {
785 			goto cleanup;
786 		}
787 		break;
788 
789 	case AML_DEREF_OF_OP:	/* deref_of (obj_reference | String) */
790 
791 		/* Check for a method local or argument, or standalone String */
792 
793 		if (ACPI_GET_DESCRIPTOR_TYPE(operand[0]) ==
794 		    ACPI_DESC_TYPE_NAMED) {
795 			temp_desc =
796 			    acpi_ns_get_attached_object((struct
797 							 acpi_namespace_node *)
798 							operand[0]);
799 			if (temp_desc
800 			    && ((temp_desc->common.type == ACPI_TYPE_STRING)
801 				|| (temp_desc->common.type ==
802 				    ACPI_TYPE_LOCAL_REFERENCE))) {
803 				operand[0] = temp_desc;
804 				acpi_ut_add_reference(temp_desc);
805 			} else {
806 				status = AE_AML_OPERAND_TYPE;
807 				goto cleanup;
808 			}
809 		} else {
810 			switch ((operand[0])->common.type) {
811 			case ACPI_TYPE_LOCAL_REFERENCE:
812 				/*
813 				 * This is a deref_of (local_x | arg_x)
814 				 *
815 				 * Must resolve/dereference the local/arg reference first
816 				 */
817 				switch (operand[0]->reference.class) {
818 				case ACPI_REFCLASS_LOCAL:
819 				case ACPI_REFCLASS_ARG:
820 
821 					/* Set Operand[0] to the value of the local/arg */
822 
823 					status =
824 					    acpi_ds_method_data_get_value
825 					    (operand[0]->reference.class,
826 					     operand[0]->reference.value,
827 					     walk_state, &temp_desc);
828 					if (ACPI_FAILURE(status)) {
829 						goto cleanup;
830 					}
831 
832 					/*
833 					 * Delete our reference to the input object and
834 					 * point to the object just retrieved
835 					 */
836 					acpi_ut_remove_reference(operand[0]);
837 					operand[0] = temp_desc;
838 					break;
839 
840 				case ACPI_REFCLASS_REFOF:
841 
842 					/* Get the object to which the reference refers */
843 
844 					temp_desc =
845 					    operand[0]->reference.object;
846 					acpi_ut_remove_reference(operand[0]);
847 					operand[0] = temp_desc;
848 					break;
849 
850 				default:
851 
852 					/* Must be an Index op - handled below */
853 					break;
854 				}
855 				break;
856 
857 			case ACPI_TYPE_STRING:
858 
859 				break;
860 
861 			default:
862 
863 				status = AE_AML_OPERAND_TYPE;
864 				goto cleanup;
865 			}
866 		}
867 
868 		if (ACPI_GET_DESCRIPTOR_TYPE(operand[0]) !=
869 		    ACPI_DESC_TYPE_NAMED) {
870 			if ((operand[0])->common.type == ACPI_TYPE_STRING) {
871 				/*
872 				 * This is a deref_of (String). The string is a reference
873 				 * to a named ACPI object.
874 				 *
875 				 * 1) Find the owning Node
876 				 * 2) Dereference the node to an actual object. Could be a
877 				 *    Field, so we need to resolve the node to a value.
878 				 */
879 				status =
880 				    acpi_ns_get_node_unlocked(walk_state->
881 							      scope_info->scope.
882 							      node,
883 							      operand[0]->
884 							      string.pointer,
885 							      ACPI_NS_SEARCH_PARENT,
886 							      ACPI_CAST_INDIRECT_PTR
887 							      (struct
888 							       acpi_namespace_node,
889 							       &return_desc));
890 				if (ACPI_FAILURE(status)) {
891 					goto cleanup;
892 				}
893 
894 				status =
895 				    acpi_ex_resolve_node_to_value
896 				    (ACPI_CAST_INDIRECT_PTR
897 				     (struct acpi_namespace_node, &return_desc),
898 				     walk_state);
899 				goto cleanup;
900 			}
901 		}
902 
903 		/* Operand[0] may have changed from the code above */
904 
905 		if (ACPI_GET_DESCRIPTOR_TYPE(operand[0]) ==
906 		    ACPI_DESC_TYPE_NAMED) {
907 			/*
908 			 * This is a deref_of (object_reference)
909 			 * Get the actual object from the Node (This is the dereference).
910 			 * This case may only happen when a local_x or arg_x is
911 			 * dereferenced above, or for references to device and
912 			 * thermal objects.
913 			 */
914 			switch (((struct acpi_namespace_node *)operand[0])->
915 				type) {
916 			case ACPI_TYPE_DEVICE:
917 			case ACPI_TYPE_THERMAL:
918 
919 				/* These types have no node subobject, return the NS node */
920 
921 				return_desc = operand[0];
922 				break;
923 
924 			default:
925 				/* For most types, get the object attached to the node */
926 
927 				return_desc = acpi_ns_get_attached_object((struct acpi_namespace_node *)operand[0]);
928 				acpi_ut_add_reference(return_desc);
929 				break;
930 			}
931 		} else {
932 			/*
933 			 * This must be a reference object produced by either the
934 			 * Index() or ref_of() operator
935 			 */
936 			switch (operand[0]->reference.class) {
937 			case ACPI_REFCLASS_INDEX:
938 				/*
939 				 * The target type for the Index operator must be
940 				 * either a Buffer or a Package
941 				 */
942 				switch (operand[0]->reference.target_type) {
943 				case ACPI_TYPE_BUFFER_FIELD:
944 
945 					temp_desc =
946 					    operand[0]->reference.object;
947 
948 					/*
949 					 * Create a new object that contains one element of the
950 					 * buffer -- the element pointed to by the index.
951 					 *
952 					 * NOTE: index into a buffer is NOT a pointer to a
953 					 * sub-buffer of the main buffer, it is only a pointer to a
954 					 * single element (byte) of the buffer!
955 					 *
956 					 * Since we are returning the value of the buffer at the
957 					 * indexed location, we don't need to add an additional
958 					 * reference to the buffer itself.
959 					 */
960 					return_desc =
961 					    acpi_ut_create_integer_object((u64)
962 									  temp_desc->buffer.pointer[operand[0]->reference.value]);
963 					if (!return_desc) {
964 						status = AE_NO_MEMORY;
965 						goto cleanup;
966 					}
967 					break;
968 
969 				case ACPI_TYPE_PACKAGE:
970 					/*
971 					 * Return the referenced element of the package. We must
972 					 * add another reference to the referenced object, however.
973 					 */
974 					return_desc =
975 					    *(operand[0]->reference.where);
976 					if (!return_desc) {
977 						/*
978 						 * Element is NULL, do not allow the dereference.
979 						 * This provides compatibility with other ACPI
980 						 * implementations.
981 						 */
982 						return_ACPI_STATUS
983 						    (AE_AML_UNINITIALIZED_ELEMENT);
984 					}
985 
986 					acpi_ut_add_reference(return_desc);
987 					break;
988 
989 				default:
990 
991 					ACPI_ERROR((AE_INFO,
992 						    "Unknown Index TargetType 0x%X in reference object %p",
993 						    operand[0]->reference.
994 						    target_type, operand[0]));
995 
996 					status = AE_AML_OPERAND_TYPE;
997 					goto cleanup;
998 				}
999 				break;
1000 
1001 			case ACPI_REFCLASS_REFOF:
1002 
1003 				return_desc = operand[0]->reference.object;
1004 
1005 				if (ACPI_GET_DESCRIPTOR_TYPE(return_desc) ==
1006 				    ACPI_DESC_TYPE_NAMED) {
1007 					return_desc =
1008 					    acpi_ns_get_attached_object((struct
1009 									 acpi_namespace_node
1010 									 *)
1011 									return_desc);
1012 					if (!return_desc) {
1013 						break;
1014 					}
1015 
1016 					/*
1017 					 * June 2013:
1018 					 * buffer_fields/field_units require additional resolution
1019 					 */
1020 					switch (return_desc->common.type) {
1021 					case ACPI_TYPE_BUFFER_FIELD:
1022 					case ACPI_TYPE_LOCAL_REGION_FIELD:
1023 					case ACPI_TYPE_LOCAL_BANK_FIELD:
1024 					case ACPI_TYPE_LOCAL_INDEX_FIELD:
1025 
1026 						status =
1027 						    acpi_ex_read_data_from_field
1028 						    (walk_state, return_desc,
1029 						     &temp_desc);
1030 						if (ACPI_FAILURE(status)) {
1031 							return_ACPI_STATUS
1032 							    (status);
1033 						}
1034 
1035 						return_desc = temp_desc;
1036 						break;
1037 
1038 					default:
1039 
1040 						/* Add another reference to the object */
1041 
1042 						acpi_ut_add_reference
1043 						    (return_desc);
1044 						break;
1045 					}
1046 				}
1047 				break;
1048 
1049 			default:
1050 
1051 				ACPI_ERROR((AE_INFO,
1052 					    "Unknown class in reference(%p) - 0x%2.2X",
1053 					    operand[0],
1054 					    operand[0]->reference.class));
1055 
1056 				status = AE_TYPE;
1057 				goto cleanup;
1058 			}
1059 		}
1060 		break;
1061 
1062 	default:
1063 
1064 		ACPI_ERROR((AE_INFO, "Unknown AML opcode 0x%X",
1065 			    walk_state->opcode));
1066 
1067 		status = AE_AML_BAD_OPCODE;
1068 		goto cleanup;
1069 	}
1070 
1071 cleanup:
1072 
1073 	/* Delete return object on error */
1074 
1075 	if (ACPI_FAILURE(status)) {
1076 		acpi_ut_remove_reference(return_desc);
1077 	}
1078 
1079 	/* Save return object on success */
1080 
1081 	else {
1082 		walk_state->result_obj = return_desc;
1083 	}
1084 
1085 	return_ACPI_STATUS(status);
1086 }
1087