nsaccess.c revision 95b482a8d31116f3f5c2a5089569393234d06385 
1/*******************************************************************************
2 *
3 * Module Name: nsaccess - Top-level functions for accessing ACPI namespace
4 *
5 ******************************************************************************/
6
7/*
8 * Copyright (C) 2000 - 2008, 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 <acpi/accommon.h>
46#include <acpi/amlcode.h>
47#include <acpi/acnamesp.h>
48#include <acpi/acdispat.h>
49
50#define _COMPONENT          ACPI_NAMESPACE
51ACPI_MODULE_NAME("nsaccess")
52
53/*******************************************************************************
54 *
55 * FUNCTION:    acpi_ns_root_initialize
56 *
57 * PARAMETERS:  None
58 *
59 * RETURN:      Status
60 *
61 * DESCRIPTION: Allocate and initialize the default root named objects
62 *
63 * MUTEX:       Locks namespace for entire execution
64 *
65 ******************************************************************************/
66acpi_status acpi_ns_root_initialize(void)
67{
68	acpi_status status;
69	const struct acpi_predefined_names *init_val = NULL;
70	struct acpi_namespace_node *new_node;
71	union acpi_operand_object *obj_desc;
72	acpi_string val = NULL;
73
74	ACPI_FUNCTION_TRACE(ns_root_initialize);
75
76	status = acpi_ut_acquire_mutex(ACPI_MTX_NAMESPACE);
77	if (ACPI_FAILURE(status)) {
78		return_ACPI_STATUS(status);
79	}
80
81	/*
82	 * The global root ptr is initially NULL, so a non-NULL value indicates
83	 * that acpi_ns_root_initialize() has already been called; just return.
84	 */
85	if (acpi_gbl_root_node) {
86		status = AE_OK;
87		goto unlock_and_exit;
88	}
89
90	/*
91	 * Tell the rest of the subsystem that the root is initialized
92	 * (This is OK because the namespace is locked)
93	 */
94	acpi_gbl_root_node = &acpi_gbl_root_node_struct;
95
96	/* Enter the pre-defined names in the name table */
97
98	ACPI_DEBUG_PRINT((ACPI_DB_INFO,
99			  "Entering predefined entries into namespace\n"));
100
101	for (init_val = acpi_gbl_pre_defined_names; init_val->name; init_val++) {
102
103		/* _OSI is optional for now, will be permanent later */
104
105		if (!ACPI_STRCMP(init_val->name, "_OSI")
106		    && !acpi_gbl_create_osi_method) {
107			continue;
108		}
109
110		status = acpi_ns_lookup(NULL, init_val->name, init_val->type,
111					ACPI_IMODE_LOAD_PASS2,
112					ACPI_NS_NO_UPSEARCH, NULL, &new_node);
113
114		if (ACPI_FAILURE(status) || (!new_node)) {	/* Must be on same line for code converter */
115			ACPI_EXCEPTION((AE_INFO, status,
116					"Could not create predefined name %s",
117					init_val->name));
118		}
119
120		/*
121		 * Name entered successfully.
122		 * If entry in pre_defined_names[] specifies an
123		 * initial value, create the initial value.
124		 */
125		if (init_val->val) {
126			status = acpi_os_predefined_override(init_val, &val);
127			if (ACPI_FAILURE(status)) {
128				ACPI_ERROR((AE_INFO,
129					    "Could not override predefined %s",
130					    init_val->name));
131			}
132
133			if (!val) {
134				val = init_val->val;
135			}
136
137			/*
138			 * Entry requests an initial value, allocate a
139			 * descriptor for it.
140			 */
141			obj_desc =
142			    acpi_ut_create_internal_object(init_val->type);
143			if (!obj_desc) {
144				status = AE_NO_MEMORY;
145				goto unlock_and_exit;
146			}
147
148			/*
149			 * Convert value string from table entry to
150			 * internal representation. Only types actually
151			 * used for initial values are implemented here.
152			 */
153			switch (init_val->type) {
154			case ACPI_TYPE_METHOD:
155				obj_desc->method.param_count =
156				    (u8) ACPI_TO_INTEGER(val);
157				obj_desc->common.flags |= AOPOBJ_DATA_VALID;
158
159#if defined (ACPI_ASL_COMPILER)
160
161				/* Save the parameter count for the i_aSL compiler */
162
163				new_node->value = obj_desc->method.param_count;
164#else
165				/* Mark this as a very SPECIAL method */
166
167				obj_desc->method.method_flags =
168				    AML_METHOD_INTERNAL_ONLY;
169				obj_desc->method.implementation =
170				    acpi_ut_osi_implementation;
171#endif
172				break;
173
174			case ACPI_TYPE_INTEGER:
175
176				obj_desc->integer.value = ACPI_TO_INTEGER(val);
177				break;
178
179			case ACPI_TYPE_STRING:
180
181				/*
182				 * Build an object around the static string
183				 */
184				obj_desc->string.length =
185				    (u32) ACPI_STRLEN(val);
186				obj_desc->string.pointer = val;
187				obj_desc->common.flags |= AOPOBJ_STATIC_POINTER;
188				break;
189
190			case ACPI_TYPE_MUTEX:
191
192				obj_desc->mutex.node = new_node;
193				obj_desc->mutex.sync_level =
194				    (u8) (ACPI_TO_INTEGER(val) - 1);
195
196				/* Create a mutex */
197
198				status =
199				    acpi_os_create_mutex(&obj_desc->mutex.
200							 os_mutex);
201				if (ACPI_FAILURE(status)) {
202					acpi_ut_remove_reference(obj_desc);
203					goto unlock_and_exit;
204				}
205
206				/* Special case for ACPI Global Lock */
207
208				if (ACPI_STRCMP(init_val->name, "_GL_") == 0) {
209					acpi_gbl_global_lock_mutex = obj_desc;
210
211					/* Create additional counting semaphore for global lock */
212
213					status =
214					    acpi_os_create_semaphore(1, 0,
215								     &acpi_gbl_global_lock_semaphore);
216					if (ACPI_FAILURE(status)) {
217						acpi_ut_remove_reference
218						    (obj_desc);
219						goto unlock_and_exit;
220					}
221				}
222				break;
223
224			default:
225
226				ACPI_ERROR((AE_INFO,
227					    "Unsupported initial type value %X",
228					    init_val->type));
229				acpi_ut_remove_reference(obj_desc);
230				obj_desc = NULL;
231				continue;
232			}
233
234			/* Store pointer to value descriptor in the Node */
235
236			status = acpi_ns_attach_object(new_node, obj_desc,
237						       ACPI_GET_OBJECT_TYPE
238						       (obj_desc));
239
240			/* Remove local reference to the object */
241
242			acpi_ut_remove_reference(obj_desc);
243		}
244	}
245
246      unlock_and_exit:
247	(void)acpi_ut_release_mutex(ACPI_MTX_NAMESPACE);
248
249	/* Save a handle to "_GPE", it is always present */
250
251	if (ACPI_SUCCESS(status)) {
252		status = acpi_ns_get_node(NULL, "\\_GPE", ACPI_NS_NO_UPSEARCH,
253					  &acpi_gbl_fadt_gpe_device);
254	}
255
256	return_ACPI_STATUS(status);
257}
258
259/*******************************************************************************
260 *
261 * FUNCTION:    acpi_ns_lookup
262 *
263 * PARAMETERS:  scope_info      - Current scope info block
264 *              Pathname        - Search pathname, in internal format
265 *                                (as represented in the AML stream)
266 *              Type            - Type associated with name
267 *              interpreter_mode - IMODE_LOAD_PASS2 => add name if not found
268 *              Flags           - Flags describing the search restrictions
269 *              walk_state      - Current state of the walk
270 *              return_node     - Where the Node is placed (if found
271 *                                or created successfully)
272 *
273 * RETURN:      Status
274 *
275 * DESCRIPTION: Find or enter the passed name in the name space.
276 *              Log an error if name not found in Exec mode.
277 *
278 * MUTEX:       Assumes namespace is locked.
279 *
280 ******************************************************************************/
281
282acpi_status
283acpi_ns_lookup(union acpi_generic_state *scope_info,
284	       char *pathname,
285	       acpi_object_type type,
286	       acpi_interpreter_mode interpreter_mode,
287	       u32 flags,
288	       struct acpi_walk_state *walk_state,
289	       struct acpi_namespace_node **return_node)
290{
291	acpi_status status;
292	char *path = pathname;
293	struct acpi_namespace_node *prefix_node;
294	struct acpi_namespace_node *current_node = NULL;
295	struct acpi_namespace_node *this_node = NULL;
296	u32 num_segments;
297	u32 num_carats;
298	acpi_name simple_name;
299	acpi_object_type type_to_check_for;
300	acpi_object_type this_search_type;
301	u32 search_parent_flag = ACPI_NS_SEARCH_PARENT;
302	u32 local_flags;
303
304	ACPI_FUNCTION_TRACE(ns_lookup);
305
306	if (!return_node) {
307		return_ACPI_STATUS(AE_BAD_PARAMETER);
308	}
309
310	local_flags = flags & ~(ACPI_NS_ERROR_IF_FOUND | ACPI_NS_SEARCH_PARENT);
311	*return_node = ACPI_ENTRY_NOT_FOUND;
312	acpi_gbl_ns_lookup_count++;
313
314	if (!acpi_gbl_root_node) {
315		return_ACPI_STATUS(AE_NO_NAMESPACE);
316	}
317
318	/*
319	 * Get the prefix scope.
320	 * A null scope means use the root scope
321	 */
322	if ((!scope_info) || (!scope_info->scope.node)) {
323		ACPI_DEBUG_PRINT((ACPI_DB_NAMES,
324				  "Null scope prefix, using root node (%p)\n",
325				  acpi_gbl_root_node));
326
327		prefix_node = acpi_gbl_root_node;
328	} else {
329		prefix_node = scope_info->scope.node;
330		if (ACPI_GET_DESCRIPTOR_TYPE(prefix_node) !=
331		    ACPI_DESC_TYPE_NAMED) {
332			ACPI_ERROR((AE_INFO, "%p is not a namespace node [%s]",
333				    prefix_node,
334				    acpi_ut_get_descriptor_name(prefix_node)));
335			return_ACPI_STATUS(AE_AML_INTERNAL);
336		}
337
338		if (!(flags & ACPI_NS_PREFIX_IS_SCOPE)) {
339			/*
340			 * This node might not be a actual "scope" node (such as a
341			 * Device/Method, etc.)  It could be a Package or other object node.
342			 * Backup up the tree to find the containing scope node.
343			 */
344			while (!acpi_ns_opens_scope(prefix_node->type) &&
345			       prefix_node->type != ACPI_TYPE_ANY) {
346				prefix_node =
347				    acpi_ns_get_parent_node(prefix_node);
348			}
349		}
350	}
351
352	/* Save type   TBD: may be no longer necessary */
353
354	type_to_check_for = type;
355
356	/*
357	 * Begin examination of the actual pathname
358	 */
359	if (!pathname) {
360
361		/* A Null name_path is allowed and refers to the root */
362
363		num_segments = 0;
364		this_node = acpi_gbl_root_node;
365		path = "";
366
367		ACPI_DEBUG_PRINT((ACPI_DB_NAMES,
368				  "Null Pathname (Zero segments), Flags=%X\n",
369				  flags));
370	} else {
371		/*
372		 * Name pointer is valid (and must be in internal name format)
373		 *
374		 * Check for scope prefixes:
375		 *
376		 * As represented in the AML stream, a namepath consists of an
377		 * optional scope prefix followed by a name segment part.
378		 *
379		 * If present, the scope prefix is either a Root Prefix (in
380		 * which case the name is fully qualified), or one or more
381		 * Parent Prefixes (in which case the name's scope is relative
382		 * to the current scope).
383		 */
384		if (*path == (u8) AML_ROOT_PREFIX) {
385
386			/* Pathname is fully qualified, start from the root */
387
388			this_node = acpi_gbl_root_node;
389			search_parent_flag = ACPI_NS_NO_UPSEARCH;
390
391			/* Point to name segment part */
392
393			path++;
394
395			ACPI_DEBUG_PRINT((ACPI_DB_NAMES,
396					  "Path is absolute from root [%p]\n",
397					  this_node));
398		} else {
399			/* Pathname is relative to current scope, start there */
400
401			ACPI_DEBUG_PRINT((ACPI_DB_NAMES,
402					  "Searching relative to prefix scope [%4.4s] (%p)\n",
403					  acpi_ut_get_node_name(prefix_node),
404					  prefix_node));
405
406			/*
407			 * Handle multiple Parent Prefixes (carat) by just getting
408			 * the parent node for each prefix instance.
409			 */
410			this_node = prefix_node;
411			num_carats = 0;
412			while (*path == (u8) AML_PARENT_PREFIX) {
413
414				/* Name is fully qualified, no search rules apply */
415
416				search_parent_flag = ACPI_NS_NO_UPSEARCH;
417				/*
418				 * Point past this prefix to the name segment
419				 * part or the next Parent Prefix
420				 */
421				path++;
422
423				/* Backup to the parent node */
424
425				num_carats++;
426				this_node = acpi_ns_get_parent_node(this_node);
427				if (!this_node) {
428
429					/* Current scope has no parent scope */
430
431					ACPI_ERROR((AE_INFO,
432						    "ACPI path has too many parent prefixes (^) - reached beyond root node"));
433					return_ACPI_STATUS(AE_NOT_FOUND);
434				}
435			}
436
437			if (search_parent_flag == ACPI_NS_NO_UPSEARCH) {
438				ACPI_DEBUG_PRINT((ACPI_DB_NAMES,
439						  "Search scope is [%4.4s], path has %d carat(s)\n",
440						  acpi_ut_get_node_name
441						  (this_node), num_carats));
442			}
443		}
444
445		/*
446		 * Determine the number of ACPI name segments in this pathname.
447		 *
448		 * The segment part consists of either:
449		 *  - A Null name segment (0)
450		 *  - A dual_name_prefix followed by two 4-byte name segments
451		 *  - A multi_name_prefix followed by a byte indicating the
452		 *      number of segments and the segments themselves.
453		 *  - A single 4-byte name segment
454		 *
455		 * Examine the name prefix opcode, if any, to determine the number of
456		 * segments.
457		 */
458		switch (*path) {
459		case 0:
460			/*
461			 * Null name after a root or parent prefixes. We already
462			 * have the correct target node and there are no name segments.
463			 */
464			num_segments = 0;
465			type = this_node->type;
466
467			ACPI_DEBUG_PRINT((ACPI_DB_NAMES,
468					  "Prefix-only Pathname (Zero name segments), Flags=%X\n",
469					  flags));
470			break;
471
472		case AML_DUAL_NAME_PREFIX:
473
474			/* More than one name_seg, search rules do not apply */
475
476			search_parent_flag = ACPI_NS_NO_UPSEARCH;
477
478			/* Two segments, point to first name segment */
479
480			num_segments = 2;
481			path++;
482
483			ACPI_DEBUG_PRINT((ACPI_DB_NAMES,
484					  "Dual Pathname (2 segments, Flags=%X)\n",
485					  flags));
486			break;
487
488		case AML_MULTI_NAME_PREFIX_OP:
489
490			/* More than one name_seg, search rules do not apply */
491
492			search_parent_flag = ACPI_NS_NO_UPSEARCH;
493
494			/* Extract segment count, point to first name segment */
495
496			path++;
497			num_segments = (u32) (u8) * path;
498			path++;
499
500			ACPI_DEBUG_PRINT((ACPI_DB_NAMES,
501					  "Multi Pathname (%d Segments, Flags=%X)\n",
502					  num_segments, flags));
503			break;
504
505		default:
506			/*
507			 * Not a Null name, no Dual or Multi prefix, hence there is
508			 * only one name segment and Pathname is already pointing to it.
509			 */
510			num_segments = 1;
511
512			ACPI_DEBUG_PRINT((ACPI_DB_NAMES,
513					  "Simple Pathname (1 segment, Flags=%X)\n",
514					  flags));
515			break;
516		}
517
518		ACPI_DEBUG_EXEC(acpi_ns_print_pathname(num_segments, path));
519	}
520
521	/*
522	 * Search namespace for each segment of the name. Loop through and
523	 * verify (or add to the namespace) each name segment.
524	 *
525	 * The object type is significant only at the last name
526	 * segment. (We don't care about the types along the path, only
527	 * the type of the final target object.)
528	 */
529	this_search_type = ACPI_TYPE_ANY;
530	current_node = this_node;
531	while (num_segments && current_node) {
532		num_segments--;
533		if (!num_segments) {
534			/*
535			 * This is the last segment, enable typechecking
536			 */
537			this_search_type = type;
538
539			/*
540			 * Only allow automatic parent search (search rules) if the caller
541			 * requested it AND we have a single, non-fully-qualified name_seg
542			 */
543			if ((search_parent_flag != ACPI_NS_NO_UPSEARCH) &&
544			    (flags & ACPI_NS_SEARCH_PARENT)) {
545				local_flags |= ACPI_NS_SEARCH_PARENT;
546			}
547
548			/* Set error flag according to caller */
549
550			if (flags & ACPI_NS_ERROR_IF_FOUND) {
551				local_flags |= ACPI_NS_ERROR_IF_FOUND;
552			}
553		}
554
555		/* Extract one ACPI name from the front of the pathname */
556
557		ACPI_MOVE_32_TO_32(&simple_name, path);
558
559		/* Try to find the single (4 character) ACPI name */
560
561		status =
562		    acpi_ns_search_and_enter(simple_name, walk_state,
563					     current_node, interpreter_mode,
564					     this_search_type, local_flags,
565					     &this_node);
566		if (ACPI_FAILURE(status)) {
567			if (status == AE_NOT_FOUND) {
568
569				/* Name not found in ACPI namespace */
570
571				ACPI_DEBUG_PRINT((ACPI_DB_NAMES,
572						  "Name [%4.4s] not found in scope [%4.4s] %p\n",
573						  (char *)&simple_name,
574						  (char *)&current_node->name,
575						  current_node));
576			}
577
578			*return_node = this_node;
579			return_ACPI_STATUS(status);
580		}
581
582		/* More segments to follow? */
583
584		if (num_segments > 0) {
585			/*
586			 * If we have an alias to an object that opens a scope (such as a
587			 * device or processor), we need to dereference the alias here so that
588			 * we can access any children of the original node (via the remaining
589			 * segments).
590			 */
591			if (this_node->type == ACPI_TYPE_LOCAL_ALIAS) {
592				if (!this_node->object) {
593					return_ACPI_STATUS(AE_NOT_EXIST);
594				}
595
596				if (acpi_ns_opens_scope
597				    (((struct acpi_namespace_node *)this_node->
598				      object)->type)) {
599					this_node =
600					    (struct acpi_namespace_node *)
601					    this_node->object;
602				}
603			}
604		}
605
606		/* Special handling for the last segment (num_segments == 0) */
607
608		else {
609			/*
610			 * Sanity typecheck of the target object:
611			 *
612			 * If 1) This is the last segment (num_segments == 0)
613			 *    2) And we are looking for a specific type
614			 *       (Not checking for TYPE_ANY)
615			 *    3) Which is not an alias
616			 *    4) Which is not a local type (TYPE_SCOPE)
617			 *    5) And the type of target object is known (not TYPE_ANY)
618			 *    6) And target object does not match what we are looking for
619			 *
620			 * Then we have a type mismatch. Just warn and ignore it.
621			 */
622			if ((type_to_check_for != ACPI_TYPE_ANY) &&
623			    (type_to_check_for != ACPI_TYPE_LOCAL_ALIAS) &&
624			    (type_to_check_for != ACPI_TYPE_LOCAL_METHOD_ALIAS)
625			    && (type_to_check_for != ACPI_TYPE_LOCAL_SCOPE)
626			    && (this_node->type != ACPI_TYPE_ANY)
627			    && (this_node->type != type_to_check_for)) {
628
629				/* Complain about a type mismatch */
630
631				ACPI_WARNING((AE_INFO,
632					      "NsLookup: Type mismatch on %4.4s (%s), searching for (%s)",
633					      ACPI_CAST_PTR(char, &simple_name),
634					      acpi_ut_get_type_name(this_node->
635								    type),
636					      acpi_ut_get_type_name
637					      (type_to_check_for)));
638			}
639
640			/*
641			 * If this is the last name segment and we are not looking for a
642			 * specific type, but the type of found object is known, use that type
643			 * to (later) see if it opens a scope.
644			 */
645			if (type == ACPI_TYPE_ANY) {
646				type = this_node->type;
647			}
648		}
649
650		/* Point to next name segment and make this node current */
651
652		path += ACPI_NAME_SIZE;
653		current_node = this_node;
654	}
655
656	/*
657	 * Always check if we need to open a new scope
658	 */
659	if (!(flags & ACPI_NS_DONT_OPEN_SCOPE) && (walk_state)) {
660		/*
661		 * If entry is a type which opens a scope, push the new scope on the
662		 * scope stack.
663		 */
664		if (acpi_ns_opens_scope(type)) {
665			status =
666			    acpi_ds_scope_stack_push(this_node, type,
667						     walk_state);
668			if (ACPI_FAILURE(status)) {
669				return_ACPI_STATUS(status);
670			}
671		}
672	}
673
674	*return_node = this_node;
675	return_ACPI_STATUS(AE_OK);
676}
677