1 /******************************************************************************
2  *
3  * Module Name: nsutils - Utilities for accessing ACPI namespace, accessing
4  *                        parents and siblings and Scope manipulation
5  *
6  *****************************************************************************/
7 
8 /*
9  * Copyright (C) 2000 - 2012, Intel Corp.
10  * All rights reserved.
11  *
12  * Redistribution and use in source and binary forms, with or without
13  * modification, are permitted provided that the following conditions
14  * are met:
15  * 1. Redistributions of source code must retain the above copyright
16  *    notice, this list of conditions, and the following disclaimer,
17  *    without modification.
18  * 2. Redistributions in binary form must reproduce at minimum a disclaimer
19  *    substantially similar to the "NO WARRANTY" disclaimer below
20  *    ("Disclaimer") and any redistribution must be conditioned upon
21  *    including a substantially similar Disclaimer requirement for further
22  *    binary redistribution.
23  * 3. Neither the names of the above-listed copyright holders nor the names
24  *    of any contributors may be used to endorse or promote products derived
25  *    from this software without specific prior written permission.
26  *
27  * Alternatively, this software may be distributed under the terms of the
28  * GNU General Public License ("GPL") version 2 as published by the Free
29  * Software Foundation.
30  *
31  * NO WARRANTY
32  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
33  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
34  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR
35  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
36  * HOLDERS OR CONTRIBUTORS BE LIABLE FOR SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
37  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
38  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
39  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
40  * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
41  * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
42  * POSSIBILITY OF SUCH DAMAGES.
43  */
44 
45 #include <acpi/acpi.h>
46 #include "accommon.h"
47 #include "acnamesp.h"
48 #include "amlcode.h"
49 #include "actables.h"
50 
51 #define _COMPONENT          ACPI_NAMESPACE
52 ACPI_MODULE_NAME("nsutils")
53 
54 /* Local prototypes */
55 static u8 acpi_ns_valid_path_separator(char sep);
56 
57 #ifdef ACPI_OBSOLETE_FUNCTIONS
58 acpi_name acpi_ns_find_parent_name(struct acpi_namespace_node *node_to_search);
59 #endif
60 
61 /*******************************************************************************
62  *
63  * FUNCTION:    acpi_ns_print_node_pathname
64  *
65  * PARAMETERS:  Node            - Object
66  *              Message         - Prefix message
67  *
68  * DESCRIPTION: Print an object's full namespace pathname
69  *              Manages allocation/freeing of a pathname buffer
70  *
71  ******************************************************************************/
72 
73 void
acpi_ns_print_node_pathname(struct acpi_namespace_node * node,const char * message)74 acpi_ns_print_node_pathname(struct acpi_namespace_node *node,
75 			    const char *message)
76 {
77 	struct acpi_buffer buffer;
78 	acpi_status status;
79 
80 	if (!node) {
81 		acpi_os_printf("[NULL NAME]");
82 		return;
83 	}
84 
85 	/* Convert handle to full pathname and print it (with supplied message) */
86 
87 	buffer.length = ACPI_ALLOCATE_LOCAL_BUFFER;
88 
89 	status = acpi_ns_handle_to_pathname(node, &buffer);
90 	if (ACPI_SUCCESS(status)) {
91 		if (message) {
92 			acpi_os_printf("%s ", message);
93 		}
94 
95 		acpi_os_printf("[%s] (Node %p)", (char *)buffer.pointer, node);
96 		ACPI_FREE(buffer.pointer);
97 	}
98 }
99 
100 /*******************************************************************************
101  *
102  * FUNCTION:    acpi_ns_valid_root_prefix
103  *
104  * PARAMETERS:  Prefix          - Character to be checked
105  *
106  * RETURN:      TRUE if a valid prefix
107  *
108  * DESCRIPTION: Check if a character is a valid ACPI Root prefix
109  *
110  ******************************************************************************/
111 
acpi_ns_valid_root_prefix(char prefix)112 u8 acpi_ns_valid_root_prefix(char prefix)
113 {
114 
115 	return ((u8) (prefix == '\\'));
116 }
117 
118 /*******************************************************************************
119  *
120  * FUNCTION:    acpi_ns_valid_path_separator
121  *
122  * PARAMETERS:  Sep         - Character to be checked
123  *
124  * RETURN:      TRUE if a valid path separator
125  *
126  * DESCRIPTION: Check if a character is a valid ACPI path separator
127  *
128  ******************************************************************************/
129 
acpi_ns_valid_path_separator(char sep)130 static u8 acpi_ns_valid_path_separator(char sep)
131 {
132 
133 	return ((u8) (sep == '.'));
134 }
135 
136 /*******************************************************************************
137  *
138  * FUNCTION:    acpi_ns_get_type
139  *
140  * PARAMETERS:  Node        - Parent Node to be examined
141  *
142  * RETURN:      Type field from Node whose handle is passed
143  *
144  * DESCRIPTION: Return the type of a Namespace node
145  *
146  ******************************************************************************/
147 
acpi_ns_get_type(struct acpi_namespace_node * node)148 acpi_object_type acpi_ns_get_type(struct acpi_namespace_node * node)
149 {
150 	ACPI_FUNCTION_TRACE(ns_get_type);
151 
152 	if (!node) {
153 		ACPI_WARNING((AE_INFO, "Null Node parameter"));
154 		return_UINT32(ACPI_TYPE_ANY);
155 	}
156 
157 	return_UINT32((acpi_object_type) node->type);
158 }
159 
160 /*******************************************************************************
161  *
162  * FUNCTION:    acpi_ns_local
163  *
164  * PARAMETERS:  Type        - A namespace object type
165  *
166  * RETURN:      LOCAL if names must be found locally in objects of the
167  *              passed type, 0 if enclosing scopes should be searched
168  *
169  * DESCRIPTION: Returns scope rule for the given object type.
170  *
171  ******************************************************************************/
172 
acpi_ns_local(acpi_object_type type)173 u32 acpi_ns_local(acpi_object_type type)
174 {
175 	ACPI_FUNCTION_TRACE(ns_local);
176 
177 	if (!acpi_ut_valid_object_type(type)) {
178 
179 		/* Type code out of range  */
180 
181 		ACPI_WARNING((AE_INFO, "Invalid Object Type 0x%X", type));
182 		return_UINT32(ACPI_NS_NORMAL);
183 	}
184 
185 	return_UINT32((u32) acpi_gbl_ns_properties[type] & ACPI_NS_LOCAL);
186 }
187 
188 /*******************************************************************************
189  *
190  * FUNCTION:    acpi_ns_get_internal_name_length
191  *
192  * PARAMETERS:  Info            - Info struct initialized with the
193  *                                external name pointer.
194  *
195  * RETURN:      None
196  *
197  * DESCRIPTION: Calculate the length of the internal (AML) namestring
198  *              corresponding to the external (ASL) namestring.
199  *
200  ******************************************************************************/
201 
acpi_ns_get_internal_name_length(struct acpi_namestring_info * info)202 void acpi_ns_get_internal_name_length(struct acpi_namestring_info *info)
203 {
204 	const char *next_external_char;
205 	u32 i;
206 
207 	ACPI_FUNCTION_ENTRY();
208 
209 	next_external_char = info->external_name;
210 	info->num_carats = 0;
211 	info->num_segments = 0;
212 	info->fully_qualified = FALSE;
213 
214 	/*
215 	 * For the internal name, the required length is 4 bytes per segment, plus
216 	 * 1 each for root_prefix, multi_name_prefix_op, segment count, trailing null
217 	 * (which is not really needed, but no there's harm in putting it there)
218 	 *
219 	 * strlen() + 1 covers the first name_seg, which has no path separator
220 	 */
221 	if (acpi_ns_valid_root_prefix(*next_external_char)) {
222 		info->fully_qualified = TRUE;
223 		next_external_char++;
224 
225 		/* Skip redundant root_prefix, like \\_SB.PCI0.SBRG.EC0 */
226 
227 		while (acpi_ns_valid_root_prefix(*next_external_char)) {
228 			next_external_char++;
229 		}
230 	} else {
231 		/* Handle Carat prefixes */
232 
233 		while (*next_external_char == '^') {
234 			info->num_carats++;
235 			next_external_char++;
236 		}
237 	}
238 
239 	/*
240 	 * Determine the number of ACPI name "segments" by counting the number of
241 	 * path separators within the string. Start with one segment since the
242 	 * segment count is [(# separators) + 1], and zero separators is ok.
243 	 */
244 	if (*next_external_char) {
245 		info->num_segments = 1;
246 		for (i = 0; next_external_char[i]; i++) {
247 			if (acpi_ns_valid_path_separator(next_external_char[i])) {
248 				info->num_segments++;
249 			}
250 		}
251 	}
252 
253 	info->length = (ACPI_NAME_SIZE * info->num_segments) +
254 	    4 + info->num_carats;
255 
256 	info->next_external_char = next_external_char;
257 }
258 
259 /*******************************************************************************
260  *
261  * FUNCTION:    acpi_ns_build_internal_name
262  *
263  * PARAMETERS:  Info            - Info struct fully initialized
264  *
265  * RETURN:      Status
266  *
267  * DESCRIPTION: Construct the internal (AML) namestring
268  *              corresponding to the external (ASL) namestring.
269  *
270  ******************************************************************************/
271 
acpi_ns_build_internal_name(struct acpi_namestring_info * info)272 acpi_status acpi_ns_build_internal_name(struct acpi_namestring_info *info)
273 {
274 	u32 num_segments = info->num_segments;
275 	char *internal_name = info->internal_name;
276 	const char *external_name = info->next_external_char;
277 	char *result = NULL;
278 	u32 i;
279 
280 	ACPI_FUNCTION_TRACE(ns_build_internal_name);
281 
282 	/* Setup the correct prefixes, counts, and pointers */
283 
284 	if (info->fully_qualified) {
285 		internal_name[0] = '\\';
286 
287 		if (num_segments <= 1) {
288 			result = &internal_name[1];
289 		} else if (num_segments == 2) {
290 			internal_name[1] = AML_DUAL_NAME_PREFIX;
291 			result = &internal_name[2];
292 		} else {
293 			internal_name[1] = AML_MULTI_NAME_PREFIX_OP;
294 			internal_name[2] = (char)num_segments;
295 			result = &internal_name[3];
296 		}
297 	} else {
298 		/*
299 		 * Not fully qualified.
300 		 * Handle Carats first, then append the name segments
301 		 */
302 		i = 0;
303 		if (info->num_carats) {
304 			for (i = 0; i < info->num_carats; i++) {
305 				internal_name[i] = '^';
306 			}
307 		}
308 
309 		if (num_segments <= 1) {
310 			result = &internal_name[i];
311 		} else if (num_segments == 2) {
312 			internal_name[i] = AML_DUAL_NAME_PREFIX;
313 			result = &internal_name[(acpi_size) i + 1];
314 		} else {
315 			internal_name[i] = AML_MULTI_NAME_PREFIX_OP;
316 			internal_name[(acpi_size) i + 1] = (char)num_segments;
317 			result = &internal_name[(acpi_size) i + 2];
318 		}
319 	}
320 
321 	/* Build the name (minus path separators) */
322 
323 	for (; num_segments; num_segments--) {
324 		for (i = 0; i < ACPI_NAME_SIZE; i++) {
325 			if (acpi_ns_valid_path_separator(*external_name) ||
326 			    (*external_name == 0)) {
327 
328 				/* Pad the segment with underscore(s) if segment is short */
329 
330 				result[i] = '_';
331 			} else {
332 				/* Convert the character to uppercase and save it */
333 
334 				result[i] =
335 				    (char)ACPI_TOUPPER((int)*external_name);
336 				external_name++;
337 			}
338 		}
339 
340 		/* Now we must have a path separator, or the pathname is bad */
341 
342 		if (!acpi_ns_valid_path_separator(*external_name) &&
343 		    (*external_name != 0)) {
344 			return_ACPI_STATUS(AE_BAD_PATHNAME);
345 		}
346 
347 		/* Move on the next segment */
348 
349 		external_name++;
350 		result += ACPI_NAME_SIZE;
351 	}
352 
353 	/* Terminate the string */
354 
355 	*result = 0;
356 
357 	if (info->fully_qualified) {
358 		ACPI_DEBUG_PRINT((ACPI_DB_EXEC,
359 				  "Returning [%p] (abs) \"\\%s\"\n",
360 				  internal_name, internal_name));
361 	} else {
362 		ACPI_DEBUG_PRINT((ACPI_DB_EXEC, "Returning [%p] (rel) \"%s\"\n",
363 				  internal_name, internal_name));
364 	}
365 
366 	return_ACPI_STATUS(AE_OK);
367 }
368 
369 /*******************************************************************************
370  *
371  * FUNCTION:    acpi_ns_internalize_name
372  *
373  * PARAMETERS:  *external_name          - External representation of name
374  *              **Converted Name        - Where to return the resulting
375  *                                        internal represention of the name
376  *
377  * RETURN:      Status
378  *
379  * DESCRIPTION: Convert an external representation (e.g. "\_PR_.CPU0")
380  *              to internal form (e.g. 5c 2f 02 5f 50 52 5f 43 50 55 30)
381  *
382  *******************************************************************************/
383 
384 acpi_status
acpi_ns_internalize_name(const char * external_name,char ** converted_name)385 acpi_ns_internalize_name(const char *external_name, char **converted_name)
386 {
387 	char *internal_name;
388 	struct acpi_namestring_info info;
389 	acpi_status status;
390 
391 	ACPI_FUNCTION_TRACE(ns_internalize_name);
392 
393 	if ((!external_name) || (*external_name == 0) || (!converted_name)) {
394 		return_ACPI_STATUS(AE_BAD_PARAMETER);
395 	}
396 
397 	/* Get the length of the new internal name */
398 
399 	info.external_name = external_name;
400 	acpi_ns_get_internal_name_length(&info);
401 
402 	/* We need a segment to store the internal  name */
403 
404 	internal_name = ACPI_ALLOCATE_ZEROED(info.length);
405 	if (!internal_name) {
406 		return_ACPI_STATUS(AE_NO_MEMORY);
407 	}
408 
409 	/* Build the name */
410 
411 	info.internal_name = internal_name;
412 	status = acpi_ns_build_internal_name(&info);
413 	if (ACPI_FAILURE(status)) {
414 		ACPI_FREE(internal_name);
415 		return_ACPI_STATUS(status);
416 	}
417 
418 	*converted_name = internal_name;
419 	return_ACPI_STATUS(AE_OK);
420 }
421 
422 /*******************************************************************************
423  *
424  * FUNCTION:    acpi_ns_externalize_name
425  *
426  * PARAMETERS:  internal_name_length - Lenth of the internal name below
427  *              internal_name       - Internal representation of name
428  *              converted_name_length - Where the length is returned
429  *              converted_name      - Where the resulting external name
430  *                                    is returned
431  *
432  * RETURN:      Status
433  *
434  * DESCRIPTION: Convert internal name (e.g. 5c 2f 02 5f 50 52 5f 43 50 55 30)
435  *              to its external (printable) form (e.g. "\_PR_.CPU0")
436  *
437  ******************************************************************************/
438 
439 acpi_status
acpi_ns_externalize_name(u32 internal_name_length,const char * internal_name,u32 * converted_name_length,char ** converted_name)440 acpi_ns_externalize_name(u32 internal_name_length,
441 			 const char *internal_name,
442 			 u32 * converted_name_length, char **converted_name)
443 {
444 	u32 names_index = 0;
445 	u32 num_segments = 0;
446 	u32 required_length;
447 	u32 prefix_length = 0;
448 	u32 i = 0;
449 	u32 j = 0;
450 
451 	ACPI_FUNCTION_TRACE(ns_externalize_name);
452 
453 	if (!internal_name_length || !internal_name || !converted_name) {
454 		return_ACPI_STATUS(AE_BAD_PARAMETER);
455 	}
456 
457 	/* Check for a prefix (one '\' | one or more '^') */
458 
459 	switch (internal_name[0]) {
460 	case '\\':
461 		prefix_length = 1;
462 		break;
463 
464 	case '^':
465 		for (i = 0; i < internal_name_length; i++) {
466 			if (internal_name[i] == '^') {
467 				prefix_length = i + 1;
468 			} else {
469 				break;
470 			}
471 		}
472 
473 		if (i == internal_name_length) {
474 			prefix_length = i;
475 		}
476 
477 		break;
478 
479 	default:
480 		break;
481 	}
482 
483 	/*
484 	 * Check for object names. Note that there could be 0-255 of these
485 	 * 4-byte elements.
486 	 */
487 	if (prefix_length < internal_name_length) {
488 		switch (internal_name[prefix_length]) {
489 		case AML_MULTI_NAME_PREFIX_OP:
490 
491 			/* <count> 4-byte names */
492 
493 			names_index = prefix_length + 2;
494 			num_segments = (u8)
495 			    internal_name[(acpi_size) prefix_length + 1];
496 			break;
497 
498 		case AML_DUAL_NAME_PREFIX:
499 
500 			/* Two 4-byte names */
501 
502 			names_index = prefix_length + 1;
503 			num_segments = 2;
504 			break;
505 
506 		case 0:
507 
508 			/* null_name */
509 
510 			names_index = 0;
511 			num_segments = 0;
512 			break;
513 
514 		default:
515 
516 			/* one 4-byte name */
517 
518 			names_index = prefix_length;
519 			num_segments = 1;
520 			break;
521 		}
522 	}
523 
524 	/*
525 	 * Calculate the length of converted_name, which equals the length
526 	 * of the prefix, length of all object names, length of any required
527 	 * punctuation ('.') between object names, plus the NULL terminator.
528 	 */
529 	required_length = prefix_length + (4 * num_segments) +
530 	    ((num_segments > 0) ? (num_segments - 1) : 0) + 1;
531 
532 	/*
533 	 * Check to see if we're still in bounds.  If not, there's a problem
534 	 * with internal_name (invalid format).
535 	 */
536 	if (required_length > internal_name_length) {
537 		ACPI_ERROR((AE_INFO, "Invalid internal name"));
538 		return_ACPI_STATUS(AE_BAD_PATHNAME);
539 	}
540 
541 	/* Build the converted_name */
542 
543 	*converted_name = ACPI_ALLOCATE_ZEROED(required_length);
544 	if (!(*converted_name)) {
545 		return_ACPI_STATUS(AE_NO_MEMORY);
546 	}
547 
548 	j = 0;
549 
550 	for (i = 0; i < prefix_length; i++) {
551 		(*converted_name)[j++] = internal_name[i];
552 	}
553 
554 	if (num_segments > 0) {
555 		for (i = 0; i < num_segments; i++) {
556 			if (i > 0) {
557 				(*converted_name)[j++] = '.';
558 			}
559 
560 			(*converted_name)[j++] = internal_name[names_index++];
561 			(*converted_name)[j++] = internal_name[names_index++];
562 			(*converted_name)[j++] = internal_name[names_index++];
563 			(*converted_name)[j++] = internal_name[names_index++];
564 		}
565 	}
566 
567 	if (converted_name_length) {
568 		*converted_name_length = (u32) required_length;
569 	}
570 
571 	return_ACPI_STATUS(AE_OK);
572 }
573 
574 /*******************************************************************************
575  *
576  * FUNCTION:    acpi_ns_validate_handle
577  *
578  * PARAMETERS:  Handle          - Handle to be validated and typecast to a
579  *                                namespace node.
580  *
581  * RETURN:      A pointer to a namespace node
582  *
583  * DESCRIPTION: Convert a namespace handle to a namespace node. Handles special
584  *              cases for the root node.
585  *
586  * NOTE: Real integer handles would allow for more verification
587  *       and keep all pointers within this subsystem - however this introduces
588  *       more overhead and has not been necessary to this point. Drivers
589  *       holding handles are typically notified before a node becomes invalid
590  *       due to a table unload.
591  *
592  ******************************************************************************/
593 
acpi_ns_validate_handle(acpi_handle handle)594 struct acpi_namespace_node *acpi_ns_validate_handle(acpi_handle handle)
595 {
596 
597 	ACPI_FUNCTION_ENTRY();
598 
599 	/* Parameter validation */
600 
601 	if ((!handle) || (handle == ACPI_ROOT_OBJECT)) {
602 		return (acpi_gbl_root_node);
603 	}
604 
605 	/* We can at least attempt to verify the handle */
606 
607 	if (ACPI_GET_DESCRIPTOR_TYPE(handle) != ACPI_DESC_TYPE_NAMED) {
608 		return (NULL);
609 	}
610 
611 	return (ACPI_CAST_PTR(struct acpi_namespace_node, handle));
612 }
613 
614 /*******************************************************************************
615  *
616  * FUNCTION:    acpi_ns_terminate
617  *
618  * PARAMETERS:  none
619  *
620  * RETURN:      none
621  *
622  * DESCRIPTION: free memory allocated for namespace and ACPI table storage.
623  *
624  ******************************************************************************/
625 
acpi_ns_terminate(void)626 void acpi_ns_terminate(void)
627 {
628 	union acpi_operand_object *obj_desc;
629 
630 	ACPI_FUNCTION_TRACE(ns_terminate);
631 
632 	/*
633 	 * 1) Free the entire namespace -- all nodes and objects
634 	 *
635 	 * Delete all object descriptors attached to namepsace nodes
636 	 */
637 	acpi_ns_delete_namespace_subtree(acpi_gbl_root_node);
638 
639 	/* Detach any objects attached to the root */
640 
641 	obj_desc = acpi_ns_get_attached_object(acpi_gbl_root_node);
642 	if (obj_desc) {
643 		acpi_ns_detach_object(acpi_gbl_root_node);
644 	}
645 
646 	ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Namespace freed\n"));
647 	return_VOID;
648 }
649 
650 /*******************************************************************************
651  *
652  * FUNCTION:    acpi_ns_opens_scope
653  *
654  * PARAMETERS:  Type        - A valid namespace type
655  *
656  * RETURN:      NEWSCOPE if the passed type "opens a name scope" according
657  *              to the ACPI specification, else 0
658  *
659  ******************************************************************************/
660 
acpi_ns_opens_scope(acpi_object_type type)661 u32 acpi_ns_opens_scope(acpi_object_type type)
662 {
663 	ACPI_FUNCTION_TRACE_STR(ns_opens_scope, acpi_ut_get_type_name(type));
664 
665 	if (!acpi_ut_valid_object_type(type)) {
666 
667 		/* type code out of range  */
668 
669 		ACPI_WARNING((AE_INFO, "Invalid Object Type 0x%X", type));
670 		return_UINT32(ACPI_NS_NORMAL);
671 	}
672 
673 	return_UINT32(((u32) acpi_gbl_ns_properties[type]) & ACPI_NS_NEWSCOPE);
674 }
675 
676 /*******************************************************************************
677  *
678  * FUNCTION:    acpi_ns_get_node
679  *
680  * PARAMETERS:  *Pathname   - Name to be found, in external (ASL) format. The
681  *                            \ (backslash) and ^ (carat) prefixes, and the
682  *                            . (period) to separate segments are supported.
683  *              prefix_node  - Root of subtree to be searched, or NS_ALL for the
684  *                            root of the name space.  If Name is fully
685  *                            qualified (first s8 is '\'), the passed value
686  *                            of Scope will not be accessed.
687  *              Flags       - Used to indicate whether to perform upsearch or
688  *                            not.
689  *              return_node - Where the Node is returned
690  *
691  * DESCRIPTION: Look up a name relative to a given scope and return the
692  *              corresponding Node.  NOTE: Scope can be null.
693  *
694  * MUTEX:       Locks namespace
695  *
696  ******************************************************************************/
697 
698 acpi_status
acpi_ns_get_node(struct acpi_namespace_node * prefix_node,const char * pathname,u32 flags,struct acpi_namespace_node ** return_node)699 acpi_ns_get_node(struct acpi_namespace_node *prefix_node,
700 		 const char *pathname,
701 		 u32 flags, struct acpi_namespace_node **return_node)
702 {
703 	union acpi_generic_state scope_info;
704 	acpi_status status;
705 	char *internal_path;
706 
707 	ACPI_FUNCTION_TRACE_PTR(ns_get_node, ACPI_CAST_PTR(char, pathname));
708 
709 	if (!pathname) {
710 		*return_node = prefix_node;
711 		if (!prefix_node) {
712 			*return_node = acpi_gbl_root_node;
713 		}
714 		return_ACPI_STATUS(AE_OK);
715 	}
716 
717 	/* Convert path to internal representation */
718 
719 	status = acpi_ns_internalize_name(pathname, &internal_path);
720 	if (ACPI_FAILURE(status)) {
721 		return_ACPI_STATUS(status);
722 	}
723 
724 	/* Must lock namespace during lookup */
725 
726 	status = acpi_ut_acquire_mutex(ACPI_MTX_NAMESPACE);
727 	if (ACPI_FAILURE(status)) {
728 		goto cleanup;
729 	}
730 
731 	/* Setup lookup scope (search starting point) */
732 
733 	scope_info.scope.node = prefix_node;
734 
735 	/* Lookup the name in the namespace */
736 
737 	status = acpi_ns_lookup(&scope_info, internal_path, ACPI_TYPE_ANY,
738 				ACPI_IMODE_EXECUTE,
739 				(flags | ACPI_NS_DONT_OPEN_SCOPE), NULL,
740 				return_node);
741 	if (ACPI_FAILURE(status)) {
742 		ACPI_DEBUG_PRINT((ACPI_DB_EXEC, "%s, %s\n",
743 				  pathname, acpi_format_exception(status)));
744 	}
745 
746 	(void)acpi_ut_release_mutex(ACPI_MTX_NAMESPACE);
747 
748       cleanup:
749 	ACPI_FREE(internal_path);
750 	return_ACPI_STATUS(status);
751 }
752