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 - 2023, 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 "acpi.h"
153#include "accommon.h"
154#include "amlcode.h"
155#include "acnamesp.h"
156#include "acdispat.h"
157
158#ifdef ACPI_ASL_COMPILER
159    #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
180ACPI_STATUS
181AcpiNsRootInitialize (
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 = AcpiNsCreateNode (*ACPI_CAST_PTR (UINT32, InitVal->Name));
255        if (!NewNode)
256        {
257            Status = AE_NO_MEMORY;
258            goto UnlockAndExit;
259        }
260
261        NewNode->DescriptorType = ACPI_DESC_TYPE_NAMED;
262        NewNode->Type = InitVal->Type;
263
264        if (!PrevNode)
265        {
266            AcpiGbl_RootNodeStruct.Child = NewNode;
267        }
268        else
269        {
270            PrevNode->Peer = NewNode;
271        }
272
273        NewNode->Parent = &AcpiGbl_RootNodeStruct;
274        PrevNode = NewNode;
275
276        /*
277         * Name entered successfully. If entry in PreDefinedNames[] specifies
278         * an initial value, create the initial value.
279         */
280        if (InitVal->Val)
281        {
282            Status = AcpiOsPredefinedOverride (InitVal, &Val);
283            if (ACPI_FAILURE (Status))
284            {
285                ACPI_ERROR ((AE_INFO,
286                    "Could not override predefined %s",
287                    InitVal->Name));
288            }
289
290            if (!Val)
291            {
292                Val = InitVal->Val;
293            }
294
295            /*
296             * Entry requests an initial value, allocate a
297             * descriptor for it.
298             */
299            ObjDesc = AcpiUtCreateInternalObject (InitVal->Type);
300            if (!ObjDesc)
301            {
302                Status = AE_NO_MEMORY;
303                goto UnlockAndExit;
304            }
305
306            /*
307             * Convert value string from table entry to
308             * internal representation. Only types actually
309             * used for initial values are implemented here.
310             */
311            switch (InitVal->Type)
312            {
313            case ACPI_TYPE_METHOD:
314
315                ObjDesc->Method.ParamCount = (UINT8) ACPI_TO_INTEGER (Val);
316                ObjDesc->Common.Flags |= AOPOBJ_DATA_VALID;
317
318#if defined (ACPI_ASL_COMPILER)
319
320                /* Save the parameter count for the iASL compiler */
321
322                NewNode->Value = ObjDesc->Method.ParamCount;
323#else
324                /* Mark this as a very SPECIAL method (_OSI) */
325
326                ObjDesc->Method.InfoFlags = ACPI_METHOD_INTERNAL_ONLY;
327                ObjDesc->Method.Dispatch.Implementation = AcpiUtOsiImplementation;
328#endif
329                break;
330
331            case ACPI_TYPE_INTEGER:
332
333                ObjDesc->Integer.Value = ACPI_TO_INTEGER (Val);
334                break;
335
336            case ACPI_TYPE_STRING:
337
338                /* Build an object around the static string */
339
340                ObjDesc->String.Length = (UINT32) strlen (Val);
341                ObjDesc->String.Pointer = Val;
342                ObjDesc->Common.Flags |= AOPOBJ_STATIC_POINTER;
343                break;
344
345            case ACPI_TYPE_MUTEX:
346
347                ObjDesc->Mutex.Node = NewNode;
348                ObjDesc->Mutex.SyncLevel = (UINT8) (ACPI_TO_INTEGER (Val) - 1);
349
350                /* Create a mutex */
351
352                Status = AcpiOsCreateMutex (&ObjDesc->Mutex.OsMutex);
353                if (ACPI_FAILURE (Status))
354                {
355                    AcpiUtRemoveReference (ObjDesc);
356                    goto UnlockAndExit;
357                }
358
359                /* Special case for ACPI Global Lock */
360
361                if (strcmp (InitVal->Name, "_GL_") == 0)
362                {
363                    AcpiGbl_GlobalLockMutex = ObjDesc;
364
365                    /* Create additional counting semaphore for global lock */
366
367                    Status = AcpiOsCreateSemaphore (
368                        1, 0, &AcpiGbl_GlobalLockSemaphore);
369                    if (ACPI_FAILURE (Status))
370                    {
371                        AcpiUtRemoveReference (ObjDesc);
372                        goto UnlockAndExit;
373                    }
374                }
375                break;
376
377            default:
378
379                ACPI_ERROR ((AE_INFO, "Unsupported initial type value 0x%X",
380                    InitVal->Type));
381                AcpiUtRemoveReference (ObjDesc);
382                ObjDesc = NULL;
383                continue;
384            }
385
386            /* Store pointer to value descriptor in the Node */
387
388            Status = AcpiNsAttachObject (NewNode, ObjDesc,
389                ObjDesc->Common.Type);
390
391            /* Remove local reference to the object */
392
393            AcpiUtRemoveReference (ObjDesc);
394        }
395    }
396
397UnlockAndExit:
398    (void) AcpiUtReleaseMutex (ACPI_MTX_NAMESPACE);
399
400    /* Save a handle to "_GPE", it is always present */
401
402    if (ACPI_SUCCESS (Status))
403    {
404        Status = AcpiNsGetNode (NULL, "\\_GPE", ACPI_NS_NO_UPSEARCH,
405            &AcpiGbl_FadtGpeDevice);
406    }
407
408    return_ACPI_STATUS (Status);
409}
410
411
412/*******************************************************************************
413 *
414 * FUNCTION:    AcpiNsLookup
415 *
416 * PARAMETERS:  ScopeInfo       - Current scope info block
417 *              Pathname        - Search pathname, in internal format
418 *                                (as represented in the AML stream)
419 *              Type            - Type associated with name
420 *              InterpreterMode - IMODE_LOAD_PASS2 => add name if not found
421 *              Flags           - Flags describing the search restrictions
422 *              WalkState       - Current state of the walk
423 *              ReturnNode      - Where the Node is placed (if found
424 *                                or created successfully)
425 *
426 * RETURN:      Status
427 *
428 * DESCRIPTION: Find or enter the passed name in the name space.
429 *              Log an error if name not found in Exec mode.
430 *
431 * MUTEX:       Assumes namespace is locked.
432 *
433 ******************************************************************************/
434
435ACPI_STATUS
436AcpiNsLookup (
437    ACPI_GENERIC_STATE      *ScopeInfo,
438    char                    *Pathname,
439    ACPI_OBJECT_TYPE        Type,
440    ACPI_INTERPRETER_MODE   InterpreterMode,
441    UINT32                  Flags,
442    ACPI_WALK_STATE         *WalkState,
443    ACPI_NAMESPACE_NODE     **ReturnNode)
444{
445    ACPI_STATUS             Status;
446    char                    *Path = Pathname;
447    char                    *ExternalPath;
448    ACPI_NAMESPACE_NODE     *PrefixNode;
449    ACPI_NAMESPACE_NODE     *CurrentNode = NULL;
450    ACPI_NAMESPACE_NODE     *ThisNode = NULL;
451    UINT32                  NumSegments;
452    UINT32                  NumCarats;
453    ACPI_NAME               SimpleName;
454    ACPI_OBJECT_TYPE        TypeToCheckFor;
455    ACPI_OBJECT_TYPE        ThisSearchType;
456    UINT32                  SearchParentFlag = ACPI_NS_SEARCH_PARENT;
457    UINT32                  LocalFlags;
458    ACPI_INTERPRETER_MODE   LocalInterpreterMode;
459
460
461    ACPI_FUNCTION_TRACE (NsLookup);
462
463
464    if (!ReturnNode)
465    {
466        return_ACPI_STATUS (AE_BAD_PARAMETER);
467    }
468
469    LocalFlags = Flags &
470        ~(ACPI_NS_ERROR_IF_FOUND | ACPI_NS_OVERRIDE_IF_FOUND |
471          ACPI_NS_SEARCH_PARENT);
472    *ReturnNode = ACPI_ENTRY_NOT_FOUND;
473    AcpiGbl_NsLookupCount++;
474
475    if (!AcpiGbl_RootNode)
476    {
477        return_ACPI_STATUS (AE_NO_NAMESPACE);
478    }
479
480    /* Get the prefix scope. A null scope means use the root scope */
481
482    if ((!ScopeInfo) ||
483        (!ScopeInfo->Scope.Node))
484    {
485        ACPI_DEBUG_PRINT ((ACPI_DB_NAMES,
486            "Null scope prefix, using root node (%p)\n",
487            AcpiGbl_RootNode));
488
489        PrefixNode = AcpiGbl_RootNode;
490    }
491    else
492    {
493        PrefixNode = ScopeInfo->Scope.Node;
494        if (ACPI_GET_DESCRIPTOR_TYPE (PrefixNode) != ACPI_DESC_TYPE_NAMED)
495        {
496            ACPI_ERROR ((AE_INFO, "%p is not a namespace node [%s]",
497                PrefixNode, AcpiUtGetDescriptorName (PrefixNode)));
498            return_ACPI_STATUS (AE_AML_INTERNAL);
499        }
500
501        if (!(Flags & ACPI_NS_PREFIX_IS_SCOPE))
502        {
503            /*
504             * This node might not be a actual "scope" node (such as a
505             * Device/Method, etc.)  It could be a Package or other object
506             * node. Backup up the tree to find the containing scope node.
507             */
508            while (!AcpiNsOpensScope (PrefixNode->Type) &&
509                    PrefixNode->Type != ACPI_TYPE_ANY)
510            {
511                PrefixNode = PrefixNode->Parent;
512            }
513        }
514    }
515
516    /* Save type. TBD: may be no longer necessary */
517
518    TypeToCheckFor = Type;
519
520    /*
521     * Begin examination of the actual pathname
522     */
523    if (!Pathname)
524    {
525        /* A Null NamePath is allowed and refers to the root */
526
527        NumSegments = 0;
528        ThisNode = AcpiGbl_RootNode;
529        Path = "";
530
531        ACPI_DEBUG_PRINT ((ACPI_DB_NAMES,
532            "Null Pathname (Zero segments), Flags=%X\n", Flags));
533    }
534    else
535    {
536        /*
537         * Name pointer is valid (and must be in internal name format)
538         *
539         * Check for scope prefixes:
540         *
541         * As represented in the AML stream, a namepath consists of an
542         * optional scope prefix followed by a name segment part.
543         *
544         * If present, the scope prefix is either a Root Prefix (in
545         * which case the name is fully qualified), or one or more
546         * Parent Prefixes (in which case the name's scope is relative
547         * to the current scope).
548         */
549        if (*Path == (UINT8) AML_ROOT_PREFIX)
550        {
551            /* Pathname is fully qualified, start from the root */
552
553            ThisNode = AcpiGbl_RootNode;
554            SearchParentFlag = ACPI_NS_NO_UPSEARCH;
555
556            /* Point to name segment part */
557
558            Path++;
559
560            ACPI_DEBUG_PRINT ((ACPI_DB_NAMES,
561                "Path is absolute from root [%p]\n", ThisNode));
562        }
563        else
564        {
565            /* Pathname is relative to current scope, start there */
566
567            ACPI_DEBUG_PRINT ((ACPI_DB_NAMES,
568                "Searching relative to prefix scope [%4.4s] (%p)\n",
569                AcpiUtGetNodeName (PrefixNode), PrefixNode));
570
571            /*
572             * Handle multiple Parent Prefixes (carat) by just getting
573             * the parent node for each prefix instance.
574             */
575            ThisNode = PrefixNode;
576            NumCarats = 0;
577            while (*Path == (UINT8) AML_PARENT_PREFIX)
578            {
579                /* Name is fully qualified, no search rules apply */
580
581                SearchParentFlag = ACPI_NS_NO_UPSEARCH;
582
583                /*
584                 * Point past this prefix to the name segment
585                 * part or the next Parent Prefix
586                 */
587                Path++;
588
589                /* Backup to the parent node */
590
591                NumCarats++;
592                ThisNode = ThisNode->Parent;
593                if (!ThisNode)
594                {
595                    /*
596                     * Current scope has no parent scope. Externalize
597                     * the internal path for error message.
598                     */
599                    Status = AcpiNsExternalizeName (ACPI_UINT32_MAX, Pathname,
600                        NULL, &ExternalPath);
601                    if (ACPI_SUCCESS (Status))
602                    {
603                        ACPI_ERROR ((AE_INFO,
604                            "%s: Path has too many parent prefixes (^)",
605                            ExternalPath));
606
607                        ACPI_FREE (ExternalPath);
608                    }
609
610                    return_ACPI_STATUS (AE_NOT_FOUND);
611                }
612            }
613
614            if (SearchParentFlag == ACPI_NS_NO_UPSEARCH)
615            {
616                ACPI_DEBUG_PRINT ((ACPI_DB_NAMES,
617                    "Search scope is [%4.4s], path has %u carat(s)\n",
618                    AcpiUtGetNodeName (ThisNode), NumCarats));
619            }
620        }
621
622        /*
623         * Determine the number of ACPI name segments in this pathname.
624         *
625         * The segment part consists of either:
626         *  - A Null name segment (0)
627         *  - A DualNamePrefix followed by two 4-byte name segments
628         *  - A MultiNamePrefix followed by a byte indicating the
629         *      number of segments and the segments themselves.
630         *  - A single 4-byte name segment
631         *
632         * Examine the name prefix opcode, if any, to determine the number of
633         * segments.
634         */
635        switch (*Path)
636        {
637        case 0:
638            /*
639             * Null name after a root or parent prefixes. We already
640             * have the correct target node and there are no name segments.
641             */
642            NumSegments  = 0;
643            Type = ThisNode->Type;
644
645            ACPI_DEBUG_PRINT ((ACPI_DB_NAMES,
646                "Prefix-only Pathname (Zero name segments), Flags=%X\n",
647                Flags));
648            break;
649
650        case AML_DUAL_NAME_PREFIX:
651
652            /* More than one NameSeg, search rules do not apply */
653
654            SearchParentFlag = ACPI_NS_NO_UPSEARCH;
655
656            /* Two segments, point to first name segment */
657
658            NumSegments = 2;
659            Path++;
660
661            ACPI_DEBUG_PRINT ((ACPI_DB_NAMES,
662                "Dual Pathname (2 segments, Flags=%X)\n", Flags));
663            break;
664
665        case AML_MULTI_NAME_PREFIX:
666
667            /* More than one NameSeg, search rules do not apply */
668
669            SearchParentFlag = ACPI_NS_NO_UPSEARCH;
670
671            /* Extract segment count, point to first name segment */
672
673            Path++;
674            NumSegments = (UINT32) (UINT8) *Path;
675            Path++;
676
677            ACPI_DEBUG_PRINT ((ACPI_DB_NAMES,
678                "Multi Pathname (%u Segments, Flags=%X)\n",
679                NumSegments, Flags));
680            break;
681
682        default:
683            /*
684             * Not a Null name, no Dual or Multi prefix, hence there is
685             * only one name segment and Pathname is already pointing to it.
686             */
687            NumSegments = 1;
688
689            ACPI_DEBUG_PRINT ((ACPI_DB_NAMES,
690                "Simple Pathname (1 segment, Flags=%X)\n", Flags));
691            break;
692        }
693
694        ACPI_DEBUG_EXEC (AcpiNsPrintPathname (NumSegments, Path));
695    }
696
697
698    /*
699     * Search namespace for each segment of the name. Loop through and
700     * verify (or add to the namespace) each name segment.
701     *
702     * The object type is significant only at the last name
703     * segment. (We don't care about the types along the path, only
704     * the type of the final target object.)
705     */
706    ThisSearchType = ACPI_TYPE_ANY;
707    CurrentNode = ThisNode;
708
709    while (NumSegments && CurrentNode)
710    {
711        NumSegments--;
712        if (!NumSegments)
713        {
714            /* This is the last segment, enable typechecking */
715
716            ThisSearchType = Type;
717
718            /*
719             * Only allow automatic parent search (search rules) if the caller
720             * requested it AND we have a single, non-fully-qualified NameSeg
721             */
722            if ((SearchParentFlag != ACPI_NS_NO_UPSEARCH) &&
723                (Flags & ACPI_NS_SEARCH_PARENT))
724            {
725                LocalFlags |= ACPI_NS_SEARCH_PARENT;
726            }
727
728            /* Set error flag according to caller */
729
730            if (Flags & ACPI_NS_ERROR_IF_FOUND)
731            {
732                LocalFlags |= ACPI_NS_ERROR_IF_FOUND;
733            }
734
735            /* Set override flag according to caller */
736
737            if (Flags & ACPI_NS_OVERRIDE_IF_FOUND)
738            {
739                LocalFlags |= ACPI_NS_OVERRIDE_IF_FOUND;
740            }
741        }
742
743        /* Handle opcodes that create a new NameSeg via a full NamePath */
744
745        LocalInterpreterMode = InterpreterMode;
746        if ((Flags & ACPI_NS_PREFIX_MUST_EXIST) && (NumSegments > 0))
747        {
748            /* Every element of the path must exist (except for the final NameSeg) */
749
750            LocalInterpreterMode = ACPI_IMODE_EXECUTE;
751        }
752
753        /* Extract one ACPI name from the front of the pathname */
754
755        ACPI_MOVE_32_TO_32 (&SimpleName, Path);
756
757        /* Try to find the single (4 character) ACPI name */
758
759        Status = AcpiNsSearchAndEnter (SimpleName, WalkState, CurrentNode,
760            LocalInterpreterMode, ThisSearchType, LocalFlags, &ThisNode);
761        if (ACPI_FAILURE (Status))
762        {
763            if (Status == AE_NOT_FOUND)
764            {
765#if !defined ACPI_ASL_COMPILER /* Note: iASL reports this error by itself, not needed here */
766                if (Flags & ACPI_NS_PREFIX_MUST_EXIST)
767                {
768                    AcpiOsPrintf (ACPI_MSG_BIOS_ERROR
769                        "Object does not exist: %4.4s\n", (char *) &SimpleName);
770                }
771#endif
772                /* Name not found in ACPI namespace */
773
774                ACPI_DEBUG_PRINT ((ACPI_DB_NAMES,
775                    "Name [%4.4s] not found in scope [%4.4s] %p\n",
776                    (char *) &SimpleName, (char *) &CurrentNode->Name,
777                    CurrentNode));
778            }
779
780#ifdef ACPI_EXEC_APP
781            if ((Status == AE_ALREADY_EXISTS) &&
782                (ThisNode->Flags & ANOBJ_NODE_EARLY_INIT))
783            {
784                ThisNode->Flags &= ~ANOBJ_NODE_EARLY_INIT;
785                Status = AE_OK;
786            }
787#endif
788
789#ifdef ACPI_ASL_COMPILER
790            /*
791             * If this ACPI name already exists within the namespace as an
792             * external declaration, then mark the external as a conflicting
793             * declaration and proceed to process the current node as if it did
794             * not exist in the namespace. If this node is not processed as
795             * normal, then it could cause improper namespace resolution
796             * by failing to open a new scope.
797             */
798            if (AcpiGbl_DisasmFlag &&
799                (Status == AE_ALREADY_EXISTS) &&
800                ((ThisNode->Flags & ANOBJ_IS_EXTERNAL) ||
801                    (WalkState && WalkState->Opcode == AML_EXTERNAL_OP)))
802            {
803                ThisNode->Flags &= ~ANOBJ_IS_EXTERNAL;
804                ThisNode->Type = (UINT8)ThisSearchType;
805                if (WalkState->Opcode != AML_EXTERNAL_OP)
806                {
807                    AcpiDmMarkExternalConflict (ThisNode);
808                }
809                break;
810            }
811#endif
812
813            *ReturnNode = ThisNode;
814            return_ACPI_STATUS (Status);
815        }
816
817        /* More segments to follow? */
818
819        if (NumSegments > 0)
820        {
821            /*
822             * If we have an alias to an object that opens a scope (such as a
823             * device or processor), we need to dereference the alias here so
824             * that we can access any children of the original node (via the
825             * remaining segments).
826             */
827            if (ThisNode->Type == ACPI_TYPE_LOCAL_ALIAS)
828            {
829                if (!ThisNode->Object)
830                {
831                    return_ACPI_STATUS (AE_NOT_EXIST);
832                }
833
834                if (AcpiNsOpensScope (((ACPI_NAMESPACE_NODE *)
835                        ThisNode->Object)->Type))
836                {
837                    ThisNode = (ACPI_NAMESPACE_NODE *) ThisNode->Object;
838                }
839            }
840        }
841
842        /* Special handling for the last segment (NumSegments == 0) */
843
844        else
845        {
846            /*
847             * Sanity typecheck of the target object:
848             *
849             * If 1) This is the last segment (NumSegments == 0)
850             *    2) And we are looking for a specific type
851             *       (Not checking for TYPE_ANY)
852             *    3) Which is not an alias
853             *    4) Which is not a local type (TYPE_SCOPE)
854             *    5) And the type of target object is known (not TYPE_ANY)
855             *    6) And target object does not match what we are looking for
856             *
857             * Then we have a type mismatch. Just warn and ignore it.
858             */
859            if ((TypeToCheckFor != ACPI_TYPE_ANY)                   &&
860                (TypeToCheckFor != ACPI_TYPE_LOCAL_ALIAS)           &&
861                (TypeToCheckFor != ACPI_TYPE_LOCAL_METHOD_ALIAS)    &&
862                (TypeToCheckFor != ACPI_TYPE_LOCAL_SCOPE)           &&
863                (ThisNode->Type != ACPI_TYPE_ANY)                   &&
864                (ThisNode->Type != TypeToCheckFor))
865            {
866                /* Complain about a type mismatch */
867
868                ACPI_WARNING ((AE_INFO,
869                    "NsLookup: Type mismatch on %4.4s (%s), searching for (%s)",
870                    ACPI_CAST_PTR (char, &SimpleName),
871                    AcpiUtGetTypeName (ThisNode->Type),
872                    AcpiUtGetTypeName (TypeToCheckFor)));
873            }
874
875            /*
876             * If this is the last name segment and we are not looking for a
877             * specific type, but the type of found object is known, use that
878             * type to (later) see if it opens a scope.
879             */
880            if (Type == ACPI_TYPE_ANY)
881            {
882                Type = ThisNode->Type;
883            }
884        }
885
886        /* Point to next name segment and make this node current */
887
888        Path += ACPI_NAMESEG_SIZE;
889        CurrentNode = ThisNode;
890    }
891
892    /* Always check if we need to open a new scope */
893
894    if (!(Flags & ACPI_NS_DONT_OPEN_SCOPE) && (WalkState))
895    {
896        /*
897         * If entry is a type which opens a scope, push the new scope on the
898         * scope stack.
899         */
900        if (AcpiNsOpensScope (Type))
901        {
902            Status = AcpiDsScopeStackPush (ThisNode, Type, WalkState);
903            if (ACPI_FAILURE (Status))
904            {
905                return_ACPI_STATUS (Status);
906            }
907        }
908    }
909
910#ifdef ACPI_EXEC_APP
911    if (Flags & ACPI_NS_EARLY_INIT)
912    {
913        ThisNode->Flags |= ANOBJ_NODE_EARLY_INIT;
914    }
915#endif
916
917    *ReturnNode = ThisNode;
918    return_ACPI_STATUS (AE_OK);
919}
920