1/******************************************************************************
2 *
3 * Module Name: psparse - Parser top level AML parse routines
4 *
5 *****************************************************************************/
6
7/******************************************************************************
8 *
9 * 1. Copyright Notice
10 *
11 * Some or all of this work - Copyright (c) 1999 - 2018, 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/*
153 * Parse the AML and build an operation tree as most interpreters,
154 * like Perl, do. Parsing is done by hand rather than with a YACC
155 * generated parser to tightly constrain stack and dynamic memory
156 * usage. At the same time, parsing is kept flexible and the code
157 * fairly compact by parsing based on a list of AML opcode
158 * templates in AmlOpInfo[]
159 */
160
161#include "acpi.h"
162#include "accommon.h"
163#include "acparser.h"
164#include "acdispat.h"
165#include "amlcode.h"
166#include "acinterp.h"
167#include "acnamesp.h"
168
169#define _COMPONENT          ACPI_PARSER
170        ACPI_MODULE_NAME    ("psparse")
171
172
173/*******************************************************************************
174 *
175 * FUNCTION:    AcpiPsGetOpcodeSize
176 *
177 * PARAMETERS:  Opcode          - An AML opcode
178 *
179 * RETURN:      Size of the opcode, in bytes (1 or 2)
180 *
181 * DESCRIPTION: Get the size of the current opcode.
182 *
183 ******************************************************************************/
184
185UINT32
186AcpiPsGetOpcodeSize (
187    UINT32                  Opcode)
188{
189
190    /* Extended (2-byte) opcode if > 255 */
191
192    if (Opcode > 0x00FF)
193    {
194        return (2);
195    }
196
197    /* Otherwise, just a single byte opcode */
198
199    return (1);
200}
201
202
203/*******************************************************************************
204 *
205 * FUNCTION:    AcpiPsPeekOpcode
206 *
207 * PARAMETERS:  ParserState         - A parser state object
208 *
209 * RETURN:      Next AML opcode
210 *
211 * DESCRIPTION: Get next AML opcode (without incrementing AML pointer)
212 *
213 ******************************************************************************/
214
215UINT16
216AcpiPsPeekOpcode (
217    ACPI_PARSE_STATE        *ParserState)
218{
219    UINT8                   *Aml;
220    UINT16                  Opcode;
221
222
223    Aml = ParserState->Aml;
224    Opcode = (UINT16) ACPI_GET8 (Aml);
225
226    if (Opcode == AML_EXTENDED_PREFIX)
227    {
228        /* Extended opcode, get the second opcode byte */
229
230        Aml++;
231        Opcode = (UINT16) ((Opcode << 8) | ACPI_GET8 (Aml));
232    }
233
234    return (Opcode);
235}
236
237
238/*******************************************************************************
239 *
240 * FUNCTION:    AcpiPsCompleteThisOp
241 *
242 * PARAMETERS:  WalkState       - Current State
243 *              Op              - Op to complete
244 *
245 * RETURN:      Status
246 *
247 * DESCRIPTION: Perform any cleanup at the completion of an Op.
248 *
249 ******************************************************************************/
250
251ACPI_STATUS
252AcpiPsCompleteThisOp (
253    ACPI_WALK_STATE         *WalkState,
254    ACPI_PARSE_OBJECT       *Op)
255{
256    ACPI_PARSE_OBJECT       *Prev;
257    ACPI_PARSE_OBJECT       *Next;
258    const ACPI_OPCODE_INFO  *ParentInfo;
259    ACPI_PARSE_OBJECT       *ReplacementOp = NULL;
260    ACPI_STATUS             Status = AE_OK;
261
262
263    ACPI_FUNCTION_TRACE_PTR (PsCompleteThisOp, Op);
264
265
266    /* Check for null Op, can happen if AML code is corrupt */
267
268    if (!Op)
269    {
270        return_ACPI_STATUS (AE_OK);  /* OK for now */
271    }
272
273    AcpiExStopTraceOpcode (Op, WalkState);
274
275    /* Delete this op and the subtree below it if asked to */
276
277    if (((WalkState->ParseFlags & ACPI_PARSE_TREE_MASK) != ACPI_PARSE_DELETE_TREE) ||
278         (WalkState->OpInfo->Class == AML_CLASS_ARGUMENT))
279    {
280        return_ACPI_STATUS (AE_OK);
281    }
282
283    /* Make sure that we only delete this subtree */
284
285    if (Op->Common.Parent)
286    {
287        Prev = Op->Common.Parent->Common.Value.Arg;
288        if (!Prev)
289        {
290            /* Nothing more to do */
291
292            goto Cleanup;
293        }
294
295        /*
296         * Check if we need to replace the operator and its subtree
297         * with a return value op (placeholder op)
298         */
299        ParentInfo = AcpiPsGetOpcodeInfo (Op->Common.Parent->Common.AmlOpcode);
300
301        switch (ParentInfo->Class)
302        {
303        case AML_CLASS_CONTROL:
304
305            break;
306
307        case AML_CLASS_CREATE:
308            /*
309             * These opcodes contain TermArg operands. The current
310             * op must be replaced by a placeholder return op
311             */
312            ReplacementOp = AcpiPsAllocOp (
313                AML_INT_RETURN_VALUE_OP, Op->Common.Aml);
314            if (!ReplacementOp)
315            {
316                Status = AE_NO_MEMORY;
317            }
318            break;
319
320        case AML_CLASS_NAMED_OBJECT:
321            /*
322             * These opcodes contain TermArg operands. The current
323             * op must be replaced by a placeholder return op
324             */
325            if ((Op->Common.Parent->Common.AmlOpcode == AML_REGION_OP)       ||
326                (Op->Common.Parent->Common.AmlOpcode == AML_DATA_REGION_OP)  ||
327                (Op->Common.Parent->Common.AmlOpcode == AML_BUFFER_OP)       ||
328                (Op->Common.Parent->Common.AmlOpcode == AML_PACKAGE_OP)      ||
329                (Op->Common.Parent->Common.AmlOpcode == AML_BANK_FIELD_OP)   ||
330                (Op->Common.Parent->Common.AmlOpcode == AML_VARIABLE_PACKAGE_OP))
331            {
332                ReplacementOp = AcpiPsAllocOp (
333                    AML_INT_RETURN_VALUE_OP, Op->Common.Aml);
334                if (!ReplacementOp)
335                {
336                    Status = AE_NO_MEMORY;
337                }
338            }
339            else if ((Op->Common.Parent->Common.AmlOpcode == AML_NAME_OP) &&
340                     (WalkState->PassNumber <= ACPI_IMODE_LOAD_PASS2))
341            {
342                if ((Op->Common.AmlOpcode == AML_BUFFER_OP) ||
343                    (Op->Common.AmlOpcode == AML_PACKAGE_OP) ||
344                    (Op->Common.AmlOpcode == AML_VARIABLE_PACKAGE_OP))
345                {
346                    ReplacementOp = AcpiPsAllocOp (Op->Common.AmlOpcode,
347                        Op->Common.Aml);
348                    if (!ReplacementOp)
349                    {
350                        Status = AE_NO_MEMORY;
351                    }
352                    else
353                    {
354                        ReplacementOp->Named.Data = Op->Named.Data;
355                        ReplacementOp->Named.Length = Op->Named.Length;
356                    }
357                }
358            }
359            break;
360
361        default:
362
363            ReplacementOp = AcpiPsAllocOp (
364                AML_INT_RETURN_VALUE_OP, Op->Common.Aml);
365            if (!ReplacementOp)
366            {
367                Status = AE_NO_MEMORY;
368            }
369        }
370
371        /* We must unlink this op from the parent tree */
372
373        if (Prev == Op)
374        {
375            /* This op is the first in the list */
376
377            if (ReplacementOp)
378            {
379                ReplacementOp->Common.Parent = Op->Common.Parent;
380                ReplacementOp->Common.Value.Arg = NULL;
381                ReplacementOp->Common.Node = Op->Common.Node;
382                Op->Common.Parent->Common.Value.Arg = ReplacementOp;
383                ReplacementOp->Common.Next = Op->Common.Next;
384            }
385            else
386            {
387                Op->Common.Parent->Common.Value.Arg = Op->Common.Next;
388            }
389        }
390
391        /* Search the parent list */
392
393        else while (Prev)
394        {
395            /* Traverse all siblings in the parent's argument list */
396
397            Next = Prev->Common.Next;
398            if (Next == Op)
399            {
400                if (ReplacementOp)
401                {
402                    ReplacementOp->Common.Parent = Op->Common.Parent;
403                    ReplacementOp->Common.Value.Arg = NULL;
404                    ReplacementOp->Common.Node = Op->Common.Node;
405                    Prev->Common.Next = ReplacementOp;
406                    ReplacementOp->Common.Next = Op->Common.Next;
407                    Next = NULL;
408                }
409                else
410                {
411                    Prev->Common.Next = Op->Common.Next;
412                    Next = NULL;
413                }
414            }
415            Prev = Next;
416        }
417    }
418
419
420Cleanup:
421
422    /* Now we can actually delete the subtree rooted at Op */
423
424    AcpiPsDeleteParseTree (Op);
425    return_ACPI_STATUS (Status);
426}
427
428
429/*******************************************************************************
430 *
431 * FUNCTION:    AcpiPsNextParseState
432 *
433 * PARAMETERS:  WalkState           - Current state
434 *              Op                  - Current parse op
435 *              CallbackStatus      - Status from previous operation
436 *
437 * RETURN:      Status
438 *
439 * DESCRIPTION: Update the parser state based upon the return exception from
440 *              the parser callback.
441 *
442 ******************************************************************************/
443
444ACPI_STATUS
445AcpiPsNextParseState (
446    ACPI_WALK_STATE         *WalkState,
447    ACPI_PARSE_OBJECT       *Op,
448    ACPI_STATUS             CallbackStatus)
449{
450    ACPI_PARSE_STATE        *ParserState = &WalkState->ParserState;
451    ACPI_STATUS             Status = AE_CTRL_PENDING;
452
453
454    ACPI_FUNCTION_TRACE_PTR (PsNextParseState, Op);
455
456
457    switch (CallbackStatus)
458    {
459    case AE_CTRL_TERMINATE:
460        /*
461         * A control method was terminated via a RETURN statement.
462         * The walk of this method is complete.
463         */
464        ParserState->Aml = ParserState->AmlEnd;
465        Status = AE_CTRL_TERMINATE;
466        break;
467
468    case AE_CTRL_BREAK:
469
470        ParserState->Aml = WalkState->AmlLastWhile;
471        WalkState->ControlState->Common.Value = FALSE;
472        Status = AE_CTRL_BREAK;
473        break;
474
475    case AE_CTRL_CONTINUE:
476
477        ParserState->Aml = WalkState->AmlLastWhile;
478        Status = AE_CTRL_CONTINUE;
479        break;
480
481    case AE_CTRL_PENDING:
482
483        ParserState->Aml = WalkState->AmlLastWhile;
484        break;
485
486#if 0
487    case AE_CTRL_SKIP:
488
489        ParserState->Aml = ParserState->Scope->ParseScope.PkgEnd;
490        Status = AE_OK;
491        break;
492#endif
493
494    case AE_CTRL_TRUE:
495        /*
496         * Predicate of an IF was true, and we are at the matching ELSE.
497         * Just close out this package
498         */
499        ParserState->Aml = AcpiPsGetNextPackageEnd (ParserState);
500        Status = AE_CTRL_PENDING;
501        break;
502
503    case AE_CTRL_FALSE:
504        /*
505         * Either an IF/WHILE Predicate was false or we encountered a BREAK
506         * opcode. In both cases, we do not execute the rest of the
507         * package;  We simply close out the parent (finishing the walk of
508         * this branch of the tree) and continue execution at the parent
509         * level.
510         */
511        ParserState->Aml = ParserState->Scope->ParseScope.PkgEnd;
512
513        /* In the case of a BREAK, just force a predicate (if any) to FALSE */
514
515        WalkState->ControlState->Common.Value = FALSE;
516        Status = AE_CTRL_END;
517        break;
518
519    case AE_CTRL_TRANSFER:
520
521        /* A method call (invocation) -- transfer control */
522
523        Status = AE_CTRL_TRANSFER;
524        WalkState->PrevOp = Op;
525        WalkState->MethodCallOp = Op;
526        WalkState->MethodCallNode = (Op->Common.Value.Arg)->Common.Node;
527
528        /* Will return value (if any) be used by the caller? */
529
530        WalkState->ReturnUsed = AcpiDsIsResultUsed (Op, WalkState);
531        break;
532
533    default:
534
535        Status = CallbackStatus;
536        if ((CallbackStatus & AE_CODE_MASK) == AE_CODE_CONTROL)
537        {
538            Status = AE_OK;
539        }
540        break;
541    }
542
543    return_ACPI_STATUS (Status);
544}
545
546
547/*******************************************************************************
548 *
549 * FUNCTION:    AcpiPsParseAml
550 *
551 * PARAMETERS:  WalkState       - Current state
552 *
553 *
554 * RETURN:      Status
555 *
556 * DESCRIPTION: Parse raw AML and return a tree of ops
557 *
558 ******************************************************************************/
559
560ACPI_STATUS
561AcpiPsParseAml (
562    ACPI_WALK_STATE         *WalkState)
563{
564    ACPI_STATUS             Status;
565    ACPI_THREAD_STATE       *Thread;
566    ACPI_THREAD_STATE       *PrevWalkList = AcpiGbl_CurrentWalkList;
567    ACPI_WALK_STATE         *PreviousWalkState;
568
569
570    ACPI_FUNCTION_TRACE (PsParseAml);
571
572    ACPI_DEBUG_PRINT ((ACPI_DB_PARSE,
573        "Entered with WalkState=%p Aml=%p size=%X\n",
574        WalkState, WalkState->ParserState.Aml,
575        WalkState->ParserState.AmlSize));
576
577    if (!WalkState->ParserState.Aml)
578    {
579        return_ACPI_STATUS (AE_BAD_ADDRESS);
580    }
581
582    /* Create and initialize a new thread state */
583
584    Thread = AcpiUtCreateThreadState ();
585    if (!Thread)
586    {
587        if (WalkState->MethodDesc)
588        {
589            /* Executing a control method - additional cleanup */
590
591            AcpiDsTerminateControlMethod (WalkState->MethodDesc, WalkState);
592        }
593
594        AcpiDsDeleteWalkState (WalkState);
595        return_ACPI_STATUS (AE_NO_MEMORY);
596    }
597
598    WalkState->Thread = Thread;
599
600    /*
601     * If executing a method, the starting SyncLevel is this method's
602     * SyncLevel
603     */
604    if (WalkState->MethodDesc)
605    {
606        WalkState->Thread->CurrentSyncLevel =
607            WalkState->MethodDesc->Method.SyncLevel;
608    }
609
610    AcpiDsPushWalkState (WalkState, Thread);
611
612    /*
613     * This global allows the AML debugger to get a handle to the currently
614     * executing control method.
615     */
616    AcpiGbl_CurrentWalkList = Thread;
617
618    /*
619     * Execute the walk loop as long as there is a valid Walk State. This
620     * handles nested control method invocations without recursion.
621     */
622    ACPI_DEBUG_PRINT ((ACPI_DB_PARSE, "State=%p\n", WalkState));
623
624    Status = AE_OK;
625    while (WalkState)
626    {
627        if (ACPI_SUCCESS (Status))
628        {
629            /*
630             * The ParseLoop executes AML until the method terminates
631             * or calls another method.
632             */
633            Status = AcpiPsParseLoop (WalkState);
634        }
635
636        ACPI_DEBUG_PRINT ((ACPI_DB_PARSE,
637            "Completed one call to walk loop, %s State=%p\n",
638            AcpiFormatException (Status), WalkState));
639
640        if (WalkState->MethodPathname && WalkState->MethodIsNested)
641        {
642            /* Optional object evaluation log */
643
644            ACPI_DEBUG_PRINT_RAW ((ACPI_DB_EVALUATION, "%-26s:  %*s%s\n",
645                "   Exit nested method",
646                (WalkState->MethodNestingDepth + 1) * 3, " ",
647                &WalkState->MethodPathname[1]));
648
649            ACPI_FREE (WalkState->MethodPathname);
650            WalkState->MethodIsNested = FALSE;
651        }
652        if (Status == AE_CTRL_TRANSFER)
653        {
654            /*
655             * A method call was detected.
656             * Transfer control to the called control method
657             */
658            Status = AcpiDsCallControlMethod (Thread, WalkState, NULL);
659            if (ACPI_FAILURE (Status))
660            {
661                Status = AcpiDsMethodError (Status, WalkState);
662            }
663
664            /*
665             * If the transfer to the new method method call worked
666             *, a new walk state was created -- get it
667             */
668            WalkState = AcpiDsGetCurrentWalkState (Thread);
669            continue;
670        }
671        else if (Status == AE_CTRL_TERMINATE)
672        {
673            Status = AE_OK;
674        }
675        else if ((Status != AE_OK) && (WalkState->MethodDesc))
676        {
677            /* Either the method parse or actual execution failed */
678
679            AcpiExExitInterpreter ();
680            if (Status == AE_ABORT_METHOD)
681            {
682                AcpiNsPrintNodePathname (
683                    WalkState->MethodNode, "Method aborted:");
684                AcpiOsPrintf ("\n");
685            }
686            else
687            {
688                ACPI_ERROR_METHOD ("Method parse/execution failed",
689                    WalkState->MethodNode, NULL, Status);
690            }
691            AcpiExEnterInterpreter ();
692
693            /* Check for possible multi-thread reentrancy problem */
694
695            if ((Status == AE_ALREADY_EXISTS) &&
696                (!(WalkState->MethodDesc->Method.InfoFlags &
697                    ACPI_METHOD_SERIALIZED)))
698            {
699                /*
700                 * Method is not serialized and tried to create an object
701                 * twice. The probable cause is that the method cannot
702                 * handle reentrancy. Mark as "pending serialized" now, and
703                 * then mark "serialized" when the last thread exits.
704                 */
705                WalkState->MethodDesc->Method.InfoFlags |=
706                    ACPI_METHOD_SERIALIZED_PENDING;
707            }
708        }
709
710        /* We are done with this walk, move on to the parent if any */
711
712        WalkState = AcpiDsPopWalkState (Thread);
713
714        /* Reset the current scope to the beginning of scope stack */
715
716        AcpiDsScopeStackClear (WalkState);
717
718        /*
719         * If we just returned from the execution of a control method or if we
720         * encountered an error during the method parse phase, there's lots of
721         * cleanup to do
722         */
723        if (((WalkState->ParseFlags & ACPI_PARSE_MODE_MASK) ==
724            ACPI_PARSE_EXECUTE &&
725            !(WalkState->ParseFlags & ACPI_PARSE_MODULE_LEVEL)) ||
726            (ACPI_FAILURE (Status)))
727        {
728            AcpiDsTerminateControlMethod (WalkState->MethodDesc, WalkState);
729        }
730
731        /* Delete this walk state and all linked control states */
732
733        AcpiPsCleanupScope (&WalkState->ParserState);
734        PreviousWalkState = WalkState;
735
736        ACPI_DEBUG_PRINT ((ACPI_DB_PARSE,
737            "ReturnValue=%p, ImplicitValue=%p State=%p\n",
738            WalkState->ReturnDesc, WalkState->ImplicitReturnObj, WalkState));
739
740        /* Check if we have restarted a preempted walk */
741
742        WalkState = AcpiDsGetCurrentWalkState (Thread);
743        if (WalkState)
744        {
745            if (ACPI_SUCCESS (Status))
746            {
747                /*
748                 * There is another walk state, restart it.
749                 * If the method return value is not used by the parent,
750                 * The object is deleted
751                 */
752                if (!PreviousWalkState->ReturnDesc)
753                {
754                    /*
755                     * In slack mode execution, if there is no return value
756                     * we should implicitly return zero (0) as a default value.
757                     */
758                    if (AcpiGbl_EnableInterpreterSlack &&
759                        !PreviousWalkState->ImplicitReturnObj)
760                    {
761                        PreviousWalkState->ImplicitReturnObj =
762                            AcpiUtCreateIntegerObject ((UINT64) 0);
763                        if (!PreviousWalkState->ImplicitReturnObj)
764                        {
765                            return_ACPI_STATUS (AE_NO_MEMORY);
766                        }
767                    }
768
769                    /* Restart the calling control method */
770
771                    Status = AcpiDsRestartControlMethod (WalkState,
772                        PreviousWalkState->ImplicitReturnObj);
773                }
774                else
775                {
776                    /*
777                     * We have a valid return value, delete any implicit
778                     * return value.
779                     */
780                    AcpiDsClearImplicitReturn (PreviousWalkState);
781
782                    Status = AcpiDsRestartControlMethod (WalkState,
783                        PreviousWalkState->ReturnDesc);
784                }
785                if (ACPI_SUCCESS (Status))
786                {
787                    WalkState->WalkType |= ACPI_WALK_METHOD_RESTART;
788                }
789            }
790            else
791            {
792                /* On error, delete any return object or implicit return */
793
794                AcpiUtRemoveReference (PreviousWalkState->ReturnDesc);
795                AcpiDsClearImplicitReturn (PreviousWalkState);
796            }
797        }
798
799        /*
800         * Just completed a 1st-level method, save the final internal return
801         * value (if any)
802         */
803        else if (PreviousWalkState->CallerReturnDesc)
804        {
805            if (PreviousWalkState->ImplicitReturnObj)
806            {
807                *(PreviousWalkState->CallerReturnDesc) =
808                    PreviousWalkState->ImplicitReturnObj;
809            }
810            else
811            {
812                 /* NULL if no return value */
813
814                *(PreviousWalkState->CallerReturnDesc) =
815                    PreviousWalkState->ReturnDesc;
816            }
817        }
818        else
819        {
820            if (PreviousWalkState->ReturnDesc)
821            {
822                /* Caller doesn't want it, must delete it */
823
824                AcpiUtRemoveReference (PreviousWalkState->ReturnDesc);
825            }
826            if (PreviousWalkState->ImplicitReturnObj)
827            {
828                /* Caller doesn't want it, must delete it */
829
830                AcpiUtRemoveReference (PreviousWalkState->ImplicitReturnObj);
831            }
832        }
833
834        AcpiDsDeleteWalkState (PreviousWalkState);
835    }
836
837    /* Normal exit */
838
839    AcpiExReleaseAllMutexes (Thread);
840    AcpiUtDeleteGenericState (ACPI_CAST_PTR (ACPI_GENERIC_STATE, Thread));
841    AcpiGbl_CurrentWalkList = PrevWalkList;
842    return_ACPI_STATUS (Status);
843}
844