xref: /freebsd/sys/contrib/dev/acpica/components/namespace/nsaccess.c (revision 6be3386466ab79a84b48429ae66244f21526d3df)
1 /*******************************************************************************
2  *
3  * Module Name: nsaccess - Top-level functions for accessing ACPI namespace
4  *
5  ******************************************************************************/
6 
7 /******************************************************************************
8  *
9  * 1. Copyright Notice
10  *
11  * Some or all of this work - Copyright (c) 1999 - 2021, Intel Corp.
12  * All rights reserved.
13  *
14  * 2. License
15  *
16  * 2.1. This is your license from Intel Corp. under its intellectual property
17  * rights. You may have additional license terms from the party that provided
18  * you this software, covering your right to use that party's intellectual
19  * property rights.
20  *
21  * 2.2. Intel grants, free of charge, to any person ("Licensee") obtaining a
22  * copy of the source code appearing in this file ("Covered Code") an
23  * irrevocable, perpetual, worldwide license under Intel's copyrights in the
24  * base code distributed originally by Intel ("Original Intel Code") to copy,
25  * make derivatives, distribute, use and display any portion of the Covered
26  * Code in any form, with the right to sublicense such rights; and
27  *
28  * 2.3. Intel grants Licensee a non-exclusive and non-transferable patent
29  * license (with the right to sublicense), under only those claims of Intel
30  * patents that are infringed by the Original Intel Code, to make, use, sell,
31  * offer to sell, and import the Covered Code and derivative works thereof
32  * solely to the minimum extent necessary to exercise the above copyright
33  * license, and in no event shall the patent license extend to any additions
34  * to or modifications of the Original Intel Code. No other license or right
35  * is granted directly or by implication, estoppel or otherwise;
36  *
37  * The above copyright and patent license is granted only if the following
38  * conditions are met:
39  *
40  * 3. Conditions
41  *
42  * 3.1. Redistribution of Source with Rights to Further Distribute Source.
43  * Redistribution of source code of any substantial portion of the Covered
44  * Code or modification with rights to further distribute source must include
45  * the above Copyright Notice, the above License, this list of Conditions,
46  * and the following Disclaimer and Export Compliance provision. In addition,
47  * Licensee must cause all Covered Code to which Licensee contributes to
48  * contain a file documenting the changes Licensee made to create that Covered
49  * Code and the date of any change. Licensee must include in that file the
50  * documentation of any changes made by any predecessor Licensee. Licensee
51  * must include a prominent statement that the modification is derived,
52  * directly or indirectly, from Original Intel Code.
53  *
54  * 3.2. Redistribution of Source with no Rights to Further Distribute Source.
55  * Redistribution of source code of any substantial portion of the Covered
56  * Code or modification without rights to further distribute source must
57  * include the following Disclaimer and Export Compliance provision in the
58  * documentation and/or other materials provided with distribution. In
59  * addition, Licensee may not authorize further sublicense of source of any
60  * portion of the Covered Code, and must include terms to the effect that the
61  * license from Licensee to its licensee is limited to the intellectual
62  * property embodied in the software Licensee provides to its licensee, and
63  * not to intellectual property embodied in modifications its licensee may
64  * make.
65  *
66  * 3.3. Redistribution of Executable. Redistribution in executable form of any
67  * substantial portion of the Covered Code or modification must reproduce the
68  * above Copyright Notice, and the following Disclaimer and Export Compliance
69  * provision in the documentation and/or other materials provided with the
70  * distribution.
71  *
72  * 3.4. Intel retains all right, title, and interest in and to the Original
73  * Intel Code.
74  *
75  * 3.5. Neither the name Intel nor any other trademark owned or controlled by
76  * Intel shall be used in advertising or otherwise to promote the sale, use or
77  * other dealings in products derived from or relating to the Covered Code
78  * without prior written authorization from Intel.
79  *
80  * 4. Disclaimer and Export Compliance
81  *
82  * 4.1. INTEL MAKES NO WARRANTY OF ANY KIND REGARDING ANY SOFTWARE PROVIDED
83  * HERE. ANY SOFTWARE ORIGINATING FROM INTEL OR DERIVED FROM INTEL SOFTWARE
84  * IS PROVIDED "AS IS," AND INTEL WILL NOT PROVIDE ANY SUPPORT, ASSISTANCE,
85  * INSTALLATION, TRAINING OR OTHER SERVICES. INTEL WILL NOT PROVIDE ANY
86  * UPDATES, ENHANCEMENTS OR EXTENSIONS. INTEL SPECIFICALLY DISCLAIMS ANY
87  * IMPLIED WARRANTIES OF MERCHANTABILITY, NONINFRINGEMENT AND FITNESS FOR A
88  * PARTICULAR PURPOSE.
89  *
90  * 4.2. IN NO EVENT SHALL INTEL HAVE ANY LIABILITY TO LICENSEE, ITS LICENSEES
91  * OR ANY OTHER THIRD PARTY, FOR ANY LOST PROFITS, LOST DATA, LOSS OF USE OR
92  * COSTS OF PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES, OR FOR ANY INDIRECT,
93  * SPECIAL OR CONSEQUENTIAL DAMAGES ARISING OUT OF THIS AGREEMENT, UNDER ANY
94  * CAUSE OF ACTION OR THEORY OF LIABILITY, AND IRRESPECTIVE OF WHETHER INTEL
95  * HAS ADVANCE NOTICE OF THE POSSIBILITY OF SUCH DAMAGES. THESE LIMITATIONS
96  * SHALL APPLY NOTWITHSTANDING THE FAILURE OF THE ESSENTIAL PURPOSE OF ANY
97  * LIMITED REMEDY.
98  *
99  * 4.3. Licensee shall not export, either directly or indirectly, any of this
100  * software or system incorporating such software without first obtaining any
101  * required license or other approval from the U. S. Department of Commerce or
102  * any other agency or department of the United States Government. In the
103  * event Licensee exports any such software from the United States or
104  * re-exports any such software from a foreign destination, Licensee shall
105  * ensure that the distribution and export/re-export of the software is in
106  * compliance with all laws, regulations, orders, or other restrictions of the
107  * U.S. Export Administration Regulations. Licensee agrees that neither it nor
108  * any of its subsidiaries will export/re-export any technical data, process,
109  * software, or service, directly or indirectly, to any country for which the
110  * United States government or any agency thereof requires an export license,
111  * other governmental approval, or letter of assurance, without first obtaining
112  * such license, approval or letter.
113  *
114  *****************************************************************************
115  *
116  * Alternatively, you may choose to be licensed under the terms of the
117  * following license:
118  *
119  * Redistribution and use in source and binary forms, with or without
120  * modification, are permitted provided that the following conditions
121  * are met:
122  * 1. Redistributions of source code must retain the above copyright
123  *    notice, this list of conditions, and the following disclaimer,
124  *    without modification.
125  * 2. Redistributions in binary form must reproduce at minimum a disclaimer
126  *    substantially similar to the "NO WARRANTY" disclaimer below
127  *    ("Disclaimer") and any redistribution must be conditioned upon
128  *    including a substantially similar Disclaimer requirement for further
129  *    binary redistribution.
130  * 3. Neither the names of the above-listed copyright holders nor the names
131  *    of any contributors may be used to endorse or promote products derived
132  *    from this software without specific prior written permission.
133  *
134  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
135  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
136  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
137  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
138  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
139  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
140  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
141  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
142  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
143  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
144  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
145  *
146  * Alternatively, you may choose to be licensed under the terms of the
147  * GNU General Public License ("GPL") version 2 as published by the Free
148  * Software Foundation.
149  *
150  *****************************************************************************/
151 
152 #include <contrib/dev/acpica/include/acpi.h>
153 #include <contrib/dev/acpica/include/accommon.h>
154 #include <contrib/dev/acpica/include/amlcode.h>
155 #include <contrib/dev/acpica/include/acnamesp.h>
156 #include <contrib/dev/acpica/include/acdispat.h>
157 
158 #ifdef ACPI_ASL_COMPILER
159     #include <contrib/dev/acpica/include/acdisasm.h>
160 #endif
161 
162 #define _COMPONENT          ACPI_NAMESPACE
163         ACPI_MODULE_NAME    ("nsaccess")
164 
165 
166 /*******************************************************************************
167  *
168  * FUNCTION:    AcpiNsRootInitialize
169  *
170  * PARAMETERS:  None
171  *
172  * RETURN:      Status
173  *
174  * DESCRIPTION: Allocate and initialize the default root named objects
175  *
176  * MUTEX:       Locks namespace for entire execution
177  *
178  ******************************************************************************/
179 
180 ACPI_STATUS
181 AcpiNsRootInitialize (
182     void)
183 {
184     ACPI_STATUS                 Status;
185     const ACPI_PREDEFINED_NAMES *InitVal = NULL;
186     ACPI_NAMESPACE_NODE         *NewNode;
187     ACPI_NAMESPACE_NODE         *PrevNode = NULL;
188     ACPI_OPERAND_OBJECT         *ObjDesc;
189     ACPI_STRING                 Val = NULL;
190 
191 
192     ACPI_FUNCTION_TRACE (NsRootInitialize);
193 
194 
195     Status = AcpiUtAcquireMutex (ACPI_MTX_NAMESPACE);
196     if (ACPI_FAILURE (Status))
197     {
198         return_ACPI_STATUS (Status);
199     }
200 
201     /*
202      * The global root ptr is initially NULL, so a non-NULL value indicates
203      * that AcpiNsRootInitialize() has already been called; just return.
204      */
205     if (AcpiGbl_RootNode)
206     {
207         Status = AE_OK;
208         goto UnlockAndExit;
209     }
210 
211     /*
212      * Tell the rest of the subsystem that the root is initialized
213      * (This is OK because the namespace is locked)
214      */
215     AcpiGbl_RootNode = &AcpiGbl_RootNodeStruct;
216 
217     /* Enter the predefined names in the name table */
218 
219     ACPI_DEBUG_PRINT ((ACPI_DB_INFO,
220         "Entering predefined entries into namespace\n"));
221 
222     /*
223      * Create the initial (default) namespace.
224      * This namespace looks like something similar to this:
225      *
226      *   ACPI Namespace (from Namespace Root):
227      *    0  _GPE Scope        00203160 00
228      *    0  _PR_ Scope        002031D0 00
229      *    0  _SB_ Device       00203240 00 Notify Object: 0020ADD8
230      *    0  _SI_ Scope        002032B0 00
231      *    0  _TZ_ Device       00203320 00
232      *    0  _REV Integer      00203390 00 = 0000000000000002
233      *    0  _OS_ String       00203488 00 Len 14 "Microsoft Windows NT"
234      *    0  _GL_ Mutex        00203580 00 Object 002035F0
235      *    0  _OSI Method       00203678 00 Args 1 Len 0000 Aml 00000000
236      */
237     for (InitVal = AcpiGbl_PreDefinedNames; InitVal->Name; InitVal++)
238     {
239         Status = AE_OK;
240 
241         /* _OSI is optional for now, will be permanent later */
242 
243         if (!strcmp (InitVal->Name, "_OSI") && !AcpiGbl_CreateOsiMethod)
244         {
245             continue;
246         }
247 
248         /*
249          * Create, init, and link the new predefined name
250          * Note: No need to use AcpiNsLookup here because all the
251          * predefined names are at the root level. It is much easier to
252          * just create and link the new node(s) here.
253          */
254         NewNode = ACPI_ALLOCATE_ZEROED (sizeof (ACPI_NAMESPACE_NODE));
255         if (!NewNode)
256         {
257             Status = AE_NO_MEMORY;
258             goto UnlockAndExit;
259         }
260 
261         ACPI_COPY_NAMESEG (NewNode->Name.Ascii, InitVal->Name);
262         NewNode->DescriptorType = ACPI_DESC_TYPE_NAMED;
263         NewNode->Type = InitVal->Type;
264 
265         if (!PrevNode)
266         {
267             AcpiGbl_RootNodeStruct.Child = NewNode;
268         }
269         else
270         {
271             PrevNode->Peer = NewNode;
272         }
273 
274         NewNode->Parent = &AcpiGbl_RootNodeStruct;
275         PrevNode = NewNode;
276 
277         /*
278          * Name entered successfully. If entry in PreDefinedNames[] specifies
279          * an initial value, create the initial value.
280          */
281         if (InitVal->Val)
282         {
283             Status = AcpiOsPredefinedOverride (InitVal, &Val);
284             if (ACPI_FAILURE (Status))
285             {
286                 ACPI_ERROR ((AE_INFO,
287                     "Could not override predefined %s",
288                     InitVal->Name));
289             }
290 
291             if (!Val)
292             {
293                 Val = InitVal->Val;
294             }
295 
296             /*
297              * Entry requests an initial value, allocate a
298              * descriptor for it.
299              */
300             ObjDesc = AcpiUtCreateInternalObject (InitVal->Type);
301             if (!ObjDesc)
302             {
303                 Status = AE_NO_MEMORY;
304                 goto UnlockAndExit;
305             }
306 
307             /*
308              * Convert value string from table entry to
309              * internal representation. Only types actually
310              * used for initial values are implemented here.
311              */
312             switch (InitVal->Type)
313             {
314             case ACPI_TYPE_METHOD:
315 
316                 ObjDesc->Method.ParamCount = (UINT8) ACPI_TO_INTEGER (Val);
317                 ObjDesc->Common.Flags |= AOPOBJ_DATA_VALID;
318 
319 #if defined (ACPI_ASL_COMPILER)
320 
321                 /* Save the parameter count for the iASL compiler */
322 
323                 NewNode->Value = ObjDesc->Method.ParamCount;
324 #else
325                 /* Mark this as a very SPECIAL method (_OSI) */
326 
327                 ObjDesc->Method.InfoFlags = ACPI_METHOD_INTERNAL_ONLY;
328                 ObjDesc->Method.Dispatch.Implementation = AcpiUtOsiImplementation;
329 #endif
330                 break;
331 
332             case ACPI_TYPE_INTEGER:
333 
334                 ObjDesc->Integer.Value = ACPI_TO_INTEGER (Val);
335                 break;
336 
337             case ACPI_TYPE_STRING:
338 
339                 /* Build an object around the static string */
340 
341                 ObjDesc->String.Length = (UINT32) strlen (Val);
342                 ObjDesc->String.Pointer = Val;
343                 ObjDesc->Common.Flags |= AOPOBJ_STATIC_POINTER;
344                 break;
345 
346             case ACPI_TYPE_MUTEX:
347 
348                 ObjDesc->Mutex.Node = NewNode;
349                 ObjDesc->Mutex.SyncLevel = (UINT8) (ACPI_TO_INTEGER (Val) - 1);
350 
351                 /* Create a mutex */
352 
353                 Status = AcpiOsCreateMutex (&ObjDesc->Mutex.OsMutex);
354                 if (ACPI_FAILURE (Status))
355                 {
356                     AcpiUtRemoveReference (ObjDesc);
357                     goto UnlockAndExit;
358                 }
359 
360                 /* Special case for ACPI Global Lock */
361 
362                 if (strcmp (InitVal->Name, "_GL_") == 0)
363                 {
364                     AcpiGbl_GlobalLockMutex = ObjDesc;
365 
366                     /* Create additional counting semaphore for global lock */
367 
368                     Status = AcpiOsCreateSemaphore (
369                         1, 0, &AcpiGbl_GlobalLockSemaphore);
370                     if (ACPI_FAILURE (Status))
371                     {
372                         AcpiUtRemoveReference (ObjDesc);
373                         goto UnlockAndExit;
374                     }
375                 }
376                 break;
377 
378             default:
379 
380                 ACPI_ERROR ((AE_INFO, "Unsupported initial type value 0x%X",
381                     InitVal->Type));
382                 AcpiUtRemoveReference (ObjDesc);
383                 ObjDesc = NULL;
384                 continue;
385             }
386 
387             /* Store pointer to value descriptor in the Node */
388 
389             Status = AcpiNsAttachObject (NewNode, ObjDesc,
390                 ObjDesc->Common.Type);
391 
392             /* Remove local reference to the object */
393 
394             AcpiUtRemoveReference (ObjDesc);
395         }
396     }
397 
398 UnlockAndExit:
399     (void) AcpiUtReleaseMutex (ACPI_MTX_NAMESPACE);
400 
401     /* Save a handle to "_GPE", it is always present */
402 
403     if (ACPI_SUCCESS (Status))
404     {
405         Status = AcpiNsGetNode (NULL, "\\_GPE", ACPI_NS_NO_UPSEARCH,
406             &AcpiGbl_FadtGpeDevice);
407     }
408 
409     return_ACPI_STATUS (Status);
410 }
411 
412 
413 /*******************************************************************************
414  *
415  * FUNCTION:    AcpiNsLookup
416  *
417  * PARAMETERS:  ScopeInfo       - Current scope info block
418  *              Pathname        - Search pathname, in internal format
419  *                                (as represented in the AML stream)
420  *              Type            - Type associated with name
421  *              InterpreterMode - IMODE_LOAD_PASS2 => add name if not found
422  *              Flags           - Flags describing the search restrictions
423  *              WalkState       - Current state of the walk
424  *              ReturnNode      - Where the Node is placed (if found
425  *                                or created successfully)
426  *
427  * RETURN:      Status
428  *
429  * DESCRIPTION: Find or enter the passed name in the name space.
430  *              Log an error if name not found in Exec mode.
431  *
432  * MUTEX:       Assumes namespace is locked.
433  *
434  ******************************************************************************/
435 
436 ACPI_STATUS
437 AcpiNsLookup (
438     ACPI_GENERIC_STATE      *ScopeInfo,
439     char                    *Pathname,
440     ACPI_OBJECT_TYPE        Type,
441     ACPI_INTERPRETER_MODE   InterpreterMode,
442     UINT32                  Flags,
443     ACPI_WALK_STATE         *WalkState,
444     ACPI_NAMESPACE_NODE     **ReturnNode)
445 {
446     ACPI_STATUS             Status;
447     char                    *Path = Pathname;
448     char                    *ExternalPath;
449     ACPI_NAMESPACE_NODE     *PrefixNode;
450     ACPI_NAMESPACE_NODE     *CurrentNode = NULL;
451     ACPI_NAMESPACE_NODE     *ThisNode = NULL;
452     UINT32                  NumSegments;
453     UINT32                  NumCarats;
454     ACPI_NAME               SimpleName;
455     ACPI_OBJECT_TYPE        TypeToCheckFor;
456     ACPI_OBJECT_TYPE        ThisSearchType;
457     UINT32                  SearchParentFlag = ACPI_NS_SEARCH_PARENT;
458     UINT32                  LocalFlags;
459     ACPI_INTERPRETER_MODE   LocalInterpreterMode;
460 
461 
462     ACPI_FUNCTION_TRACE (NsLookup);
463 
464 
465     if (!ReturnNode)
466     {
467         return_ACPI_STATUS (AE_BAD_PARAMETER);
468     }
469 
470     LocalFlags = Flags &
471         ~(ACPI_NS_ERROR_IF_FOUND | ACPI_NS_OVERRIDE_IF_FOUND |
472           ACPI_NS_SEARCH_PARENT);
473     *ReturnNode = ACPI_ENTRY_NOT_FOUND;
474     AcpiGbl_NsLookupCount++;
475 
476     if (!AcpiGbl_RootNode)
477     {
478         return_ACPI_STATUS (AE_NO_NAMESPACE);
479     }
480 
481     /* Get the prefix scope. A null scope means use the root scope */
482 
483     if ((!ScopeInfo) ||
484         (!ScopeInfo->Scope.Node))
485     {
486         ACPI_DEBUG_PRINT ((ACPI_DB_NAMES,
487             "Null scope prefix, using root node (%p)\n",
488             AcpiGbl_RootNode));
489 
490         PrefixNode = AcpiGbl_RootNode;
491     }
492     else
493     {
494         PrefixNode = ScopeInfo->Scope.Node;
495         if (ACPI_GET_DESCRIPTOR_TYPE (PrefixNode) != ACPI_DESC_TYPE_NAMED)
496         {
497             ACPI_ERROR ((AE_INFO, "%p is not a namespace node [%s]",
498                 PrefixNode, AcpiUtGetDescriptorName (PrefixNode)));
499             return_ACPI_STATUS (AE_AML_INTERNAL);
500         }
501 
502         if (!(Flags & ACPI_NS_PREFIX_IS_SCOPE))
503         {
504             /*
505              * This node might not be a actual "scope" node (such as a
506              * Device/Method, etc.)  It could be a Package or other object
507              * node. Backup up the tree to find the containing scope node.
508              */
509             while (!AcpiNsOpensScope (PrefixNode->Type) &&
510                     PrefixNode->Type != ACPI_TYPE_ANY)
511             {
512                 PrefixNode = PrefixNode->Parent;
513             }
514         }
515     }
516 
517     /* Save type. TBD: may be no longer necessary */
518 
519     TypeToCheckFor = Type;
520 
521     /*
522      * Begin examination of the actual pathname
523      */
524     if (!Pathname)
525     {
526         /* A Null NamePath is allowed and refers to the root */
527 
528         NumSegments = 0;
529         ThisNode = AcpiGbl_RootNode;
530         Path = "";
531 
532         ACPI_DEBUG_PRINT ((ACPI_DB_NAMES,
533             "Null Pathname (Zero segments), Flags=%X\n", Flags));
534     }
535     else
536     {
537         /*
538          * Name pointer is valid (and must be in internal name format)
539          *
540          * Check for scope prefixes:
541          *
542          * As represented in the AML stream, a namepath consists of an
543          * optional scope prefix followed by a name segment part.
544          *
545          * If present, the scope prefix is either a Root Prefix (in
546          * which case the name is fully qualified), or one or more
547          * Parent Prefixes (in which case the name's scope is relative
548          * to the current scope).
549          */
550         if (*Path == (UINT8) AML_ROOT_PREFIX)
551         {
552             /* Pathname is fully qualified, start from the root */
553 
554             ThisNode = AcpiGbl_RootNode;
555             SearchParentFlag = ACPI_NS_NO_UPSEARCH;
556 
557             /* Point to name segment part */
558 
559             Path++;
560 
561             ACPI_DEBUG_PRINT ((ACPI_DB_NAMES,
562                 "Path is absolute from root [%p]\n", ThisNode));
563         }
564         else
565         {
566             /* Pathname is relative to current scope, start there */
567 
568             ACPI_DEBUG_PRINT ((ACPI_DB_NAMES,
569                 "Searching relative to prefix scope [%4.4s] (%p)\n",
570                 AcpiUtGetNodeName (PrefixNode), PrefixNode));
571 
572             /*
573              * Handle multiple Parent Prefixes (carat) by just getting
574              * the parent node for each prefix instance.
575              */
576             ThisNode = PrefixNode;
577             NumCarats = 0;
578             while (*Path == (UINT8) AML_PARENT_PREFIX)
579             {
580                 /* Name is fully qualified, no search rules apply */
581 
582                 SearchParentFlag = ACPI_NS_NO_UPSEARCH;
583 
584                 /*
585                  * Point past this prefix to the name segment
586                  * part or the next Parent Prefix
587                  */
588                 Path++;
589 
590                 /* Backup to the parent node */
591 
592                 NumCarats++;
593                 ThisNode = ThisNode->Parent;
594                 if (!ThisNode)
595                 {
596                     /*
597                      * Current scope has no parent scope. Externalize
598                      * the internal path for error message.
599                      */
600                     Status = AcpiNsExternalizeName (ACPI_UINT32_MAX, Pathname,
601                         NULL, &ExternalPath);
602                     if (ACPI_SUCCESS (Status))
603                     {
604                         ACPI_ERROR ((AE_INFO,
605                             "%s: Path has too many parent prefixes (^)",
606                             ExternalPath));
607 
608                         ACPI_FREE (ExternalPath);
609                     }
610 
611                     return_ACPI_STATUS (AE_NOT_FOUND);
612                 }
613             }
614 
615             if (SearchParentFlag == ACPI_NS_NO_UPSEARCH)
616             {
617                 ACPI_DEBUG_PRINT ((ACPI_DB_NAMES,
618                     "Search scope is [%4.4s], path has %u carat(s)\n",
619                     AcpiUtGetNodeName (ThisNode), NumCarats));
620             }
621         }
622 
623         /*
624          * Determine the number of ACPI name segments in this pathname.
625          *
626          * The segment part consists of either:
627          *  - A Null name segment (0)
628          *  - A DualNamePrefix followed by two 4-byte name segments
629          *  - A MultiNamePrefix followed by a byte indicating the
630          *      number of segments and the segments themselves.
631          *  - A single 4-byte name segment
632          *
633          * Examine the name prefix opcode, if any, to determine the number of
634          * segments.
635          */
636         switch (*Path)
637         {
638         case 0:
639             /*
640              * Null name after a root or parent prefixes. We already
641              * have the correct target node and there are no name segments.
642              */
643             NumSegments  = 0;
644             Type = ThisNode->Type;
645 
646             ACPI_DEBUG_PRINT ((ACPI_DB_NAMES,
647                 "Prefix-only Pathname (Zero name segments), Flags=%X\n",
648                 Flags));
649             break;
650 
651         case AML_DUAL_NAME_PREFIX:
652 
653             /* More than one NameSeg, search rules do not apply */
654 
655             SearchParentFlag = ACPI_NS_NO_UPSEARCH;
656 
657             /* Two segments, point to first name segment */
658 
659             NumSegments = 2;
660             Path++;
661 
662             ACPI_DEBUG_PRINT ((ACPI_DB_NAMES,
663                 "Dual Pathname (2 segments, Flags=%X)\n", Flags));
664             break;
665 
666         case AML_MULTI_NAME_PREFIX:
667 
668             /* More than one NameSeg, search rules do not apply */
669 
670             SearchParentFlag = ACPI_NS_NO_UPSEARCH;
671 
672             /* Extract segment count, point to first name segment */
673 
674             Path++;
675             NumSegments = (UINT32) (UINT8) *Path;
676             Path++;
677 
678             ACPI_DEBUG_PRINT ((ACPI_DB_NAMES,
679                 "Multi Pathname (%u Segments, Flags=%X)\n",
680                 NumSegments, Flags));
681             break;
682 
683         default:
684             /*
685              * Not a Null name, no Dual or Multi prefix, hence there is
686              * only one name segment and Pathname is already pointing to it.
687              */
688             NumSegments = 1;
689 
690             ACPI_DEBUG_PRINT ((ACPI_DB_NAMES,
691                 "Simple Pathname (1 segment, Flags=%X)\n", Flags));
692             break;
693         }
694 
695         ACPI_DEBUG_EXEC (AcpiNsPrintPathname (NumSegments, Path));
696     }
697 
698 
699     /*
700      * Search namespace for each segment of the name. Loop through and
701      * verify (or add to the namespace) each name segment.
702      *
703      * The object type is significant only at the last name
704      * segment. (We don't care about the types along the path, only
705      * the type of the final target object.)
706      */
707     ThisSearchType = ACPI_TYPE_ANY;
708     CurrentNode = ThisNode;
709 
710     while (NumSegments && CurrentNode)
711     {
712         NumSegments--;
713         if (!NumSegments)
714         {
715             /* This is the last segment, enable typechecking */
716 
717             ThisSearchType = Type;
718 
719             /*
720              * Only allow automatic parent search (search rules) if the caller
721              * requested it AND we have a single, non-fully-qualified NameSeg
722              */
723             if ((SearchParentFlag != ACPI_NS_NO_UPSEARCH) &&
724                 (Flags & ACPI_NS_SEARCH_PARENT))
725             {
726                 LocalFlags |= ACPI_NS_SEARCH_PARENT;
727             }
728 
729             /* Set error flag according to caller */
730 
731             if (Flags & ACPI_NS_ERROR_IF_FOUND)
732             {
733                 LocalFlags |= ACPI_NS_ERROR_IF_FOUND;
734             }
735 
736             /* Set override flag according to caller */
737 
738             if (Flags & ACPI_NS_OVERRIDE_IF_FOUND)
739             {
740                 LocalFlags |= ACPI_NS_OVERRIDE_IF_FOUND;
741             }
742         }
743 
744         /* Handle opcodes that create a new NameSeg via a full NamePath */
745 
746         LocalInterpreterMode = InterpreterMode;
747         if ((Flags & ACPI_NS_PREFIX_MUST_EXIST) && (NumSegments > 0))
748         {
749             /* Every element of the path must exist (except for the final NameSeg) */
750 
751             LocalInterpreterMode = ACPI_IMODE_EXECUTE;
752         }
753 
754         /* Extract one ACPI name from the front of the pathname */
755 
756         ACPI_MOVE_32_TO_32 (&SimpleName, Path);
757 
758         /* Try to find the single (4 character) ACPI name */
759 
760         Status = AcpiNsSearchAndEnter (SimpleName, WalkState, CurrentNode,
761             LocalInterpreterMode, ThisSearchType, LocalFlags, &ThisNode);
762         if (ACPI_FAILURE (Status))
763         {
764             if (Status == AE_NOT_FOUND)
765             {
766 #if !defined ACPI_ASL_COMPILER /* Note: iASL reports this error by itself, not needed here */
767                 if (Flags & ACPI_NS_PREFIX_MUST_EXIST)
768                 {
769                     AcpiOsPrintf (ACPI_MSG_BIOS_ERROR
770                         "Object does not exist: %4.4s\n", (char *) &SimpleName);
771                 }
772 #endif
773                 /* Name not found in ACPI namespace */
774 
775                 ACPI_DEBUG_PRINT ((ACPI_DB_NAMES,
776                     "Name [%4.4s] not found in scope [%4.4s] %p\n",
777                     (char *) &SimpleName, (char *) &CurrentNode->Name,
778                     CurrentNode));
779             }
780 
781 #ifdef ACPI_EXEC_APP
782             if ((Status == AE_ALREADY_EXISTS) &&
783                 (ThisNode->Flags & ANOBJ_NODE_EARLY_INIT))
784             {
785                 ThisNode->Flags &= ~ANOBJ_NODE_EARLY_INIT;
786                 Status = AE_OK;
787             }
788 #endif
789 
790 #ifdef ACPI_ASL_COMPILER
791             /*
792              * If this ACPI name already exists within the namespace as an
793              * external declaration, then mark the external as a conflicting
794              * declaration and proceed to process the current node as if it did
795              * not exist in the namespace. If this node is not processed as
796              * normal, then it could cause improper namespace resolution
797              * by failing to open a new scope.
798              */
799             if (AcpiGbl_DisasmFlag &&
800                 (Status == AE_ALREADY_EXISTS) &&
801                 ((ThisNode->Flags & ANOBJ_IS_EXTERNAL) ||
802                     (WalkState && WalkState->Opcode == AML_EXTERNAL_OP)))
803             {
804                 ThisNode->Flags &= ~ANOBJ_IS_EXTERNAL;
805                 ThisNode->Type = (UINT8)ThisSearchType;
806                 if (WalkState->Opcode != AML_EXTERNAL_OP)
807                 {
808                     AcpiDmMarkExternalConflict (ThisNode);
809                 }
810                 break;
811             }
812 #endif
813 
814             *ReturnNode = ThisNode;
815             return_ACPI_STATUS (Status);
816         }
817 
818         /* More segments to follow? */
819 
820         if (NumSegments > 0)
821         {
822             /*
823              * If we have an alias to an object that opens a scope (such as a
824              * device or processor), we need to dereference the alias here so
825              * that we can access any children of the original node (via the
826              * remaining segments).
827              */
828             if (ThisNode->Type == ACPI_TYPE_LOCAL_ALIAS)
829             {
830                 if (!ThisNode->Object)
831                 {
832                     return_ACPI_STATUS (AE_NOT_EXIST);
833                 }
834 
835                 if (AcpiNsOpensScope (((ACPI_NAMESPACE_NODE *)
836                         ThisNode->Object)->Type))
837                 {
838                     ThisNode = (ACPI_NAMESPACE_NODE *) ThisNode->Object;
839                 }
840             }
841         }
842 
843         /* Special handling for the last segment (NumSegments == 0) */
844 
845         else
846         {
847             /*
848              * Sanity typecheck of the target object:
849              *
850              * If 1) This is the last segment (NumSegments == 0)
851              *    2) And we are looking for a specific type
852              *       (Not checking for TYPE_ANY)
853              *    3) Which is not an alias
854              *    4) Which is not a local type (TYPE_SCOPE)
855              *    5) And the type of target object is known (not TYPE_ANY)
856              *    6) And target object does not match what we are looking for
857              *
858              * Then we have a type mismatch. Just warn and ignore it.
859              */
860             if ((TypeToCheckFor != ACPI_TYPE_ANY)                   &&
861                 (TypeToCheckFor != ACPI_TYPE_LOCAL_ALIAS)           &&
862                 (TypeToCheckFor != ACPI_TYPE_LOCAL_METHOD_ALIAS)    &&
863                 (TypeToCheckFor != ACPI_TYPE_LOCAL_SCOPE)           &&
864                 (ThisNode->Type != ACPI_TYPE_ANY)                   &&
865                 (ThisNode->Type != TypeToCheckFor))
866             {
867                 /* Complain about a type mismatch */
868 
869                 ACPI_WARNING ((AE_INFO,
870                     "NsLookup: Type mismatch on %4.4s (%s), searching for (%s)",
871                     ACPI_CAST_PTR (char, &SimpleName),
872                     AcpiUtGetTypeName (ThisNode->Type),
873                     AcpiUtGetTypeName (TypeToCheckFor)));
874             }
875 
876             /*
877              * If this is the last name segment and we are not looking for a
878              * specific type, but the type of found object is known, use that
879              * type to (later) see if it opens a scope.
880              */
881             if (Type == ACPI_TYPE_ANY)
882             {
883                 Type = ThisNode->Type;
884             }
885         }
886 
887         /* Point to next name segment and make this node current */
888 
889         Path += ACPI_NAMESEG_SIZE;
890         CurrentNode = ThisNode;
891     }
892 
893     /* Always check if we need to open a new scope */
894 
895     if (!(Flags & ACPI_NS_DONT_OPEN_SCOPE) && (WalkState))
896     {
897         /*
898          * If entry is a type which opens a scope, push the new scope on the
899          * scope stack.
900          */
901         if (AcpiNsOpensScope (Type))
902         {
903             Status = AcpiDsScopeStackPush (ThisNode, Type, WalkState);
904             if (ACPI_FAILURE (Status))
905             {
906                 return_ACPI_STATUS (Status);
907             }
908         }
909     }
910 
911 #ifdef ACPI_EXEC_APP
912     if (Flags & ACPI_NS_EARLY_INIT)
913     {
914         ThisNode->Flags |= ANOBJ_NODE_EARLY_INIT;
915     }
916 #endif
917 
918     *ReturnNode = ThisNode;
919     return_ACPI_STATUS (AE_OK);
920 }
921