xref: /titanic_41/usr/src/uts/intel/io/acpica/dispatcher/dsmethod.c (revision 269552cd714f2f1e308fdde0fc69b18a7f1142b2)
1 /******************************************************************************
2  *
3  * Module Name: dsmethod - Parser/Interpreter interface - control method parsing
4  *              $Revision: 1.140 $
5  *
6  *****************************************************************************/
7 
8 /******************************************************************************
9  *
10  * 1. Copyright Notice
11  *
12  * Some or all of this work - Copyright (c) 1999 - 2008, Intel Corp.
13  * All rights reserved.
14  *
15  * 2. License
16  *
17  * 2.1. This is your license from Intel Corp. under its intellectual property
18  * rights.  You may have additional license terms from the party that provided
19  * you this software, covering your right to use that party's intellectual
20  * property rights.
21  *
22  * 2.2. Intel grants, free of charge, to any person ("Licensee") obtaining a
23  * copy of the source code appearing in this file ("Covered Code") an
24  * irrevocable, perpetual, worldwide license under Intel's copyrights in the
25  * base code distributed originally by Intel ("Original Intel Code") to copy,
26  * make derivatives, distribute, use and display any portion of the Covered
27  * Code in any form, with the right to sublicense such rights; and
28  *
29  * 2.3. Intel grants Licensee a non-exclusive and non-transferable patent
30  * license (with the right to sublicense), under only those claims of Intel
31  * patents that are infringed by the Original Intel Code, to make, use, sell,
32  * offer to sell, and import the Covered Code and derivative works thereof
33  * solely to the minimum extent necessary to exercise the above copyright
34  * license, and in no event shall the patent license extend to any additions
35  * to or modifications of the Original Intel Code.  No other license or right
36  * is granted directly or by implication, estoppel or otherwise;
37  *
38  * The above copyright and patent license is granted only if the following
39  * conditions are met:
40  *
41  * 3. Conditions
42  *
43  * 3.1. Redistribution of Source with Rights to Further Distribute Source.
44  * Redistribution of source code of any substantial portion of the Covered
45  * Code or modification with rights to further distribute source must include
46  * the above Copyright Notice, the above License, this list of Conditions,
47  * and the following Disclaimer and Export Compliance provision.  In addition,
48  * Licensee must cause all Covered Code to which Licensee contributes to
49  * contain a file documenting the changes Licensee made to create that Covered
50  * Code and the date of any change.  Licensee must include in that file the
51  * documentation of any changes made by any predecessor Licensee.  Licensee
52  * must include a prominent statement that the modification is derived,
53  * directly or indirectly, from Original Intel Code.
54  *
55  * 3.2. Redistribution of Source with no Rights to Further Distribute Source.
56  * Redistribution of source code of any substantial portion of the Covered
57  * Code or modification without rights to further distribute source must
58  * include the following Disclaimer and Export Compliance provision in the
59  * documentation and/or other materials provided with distribution.  In
60  * addition, Licensee may not authorize further sublicense of source of any
61  * portion of the Covered Code, and must include terms to the effect that the
62  * license from Licensee to its licensee is limited to the intellectual
63  * property embodied in the software Licensee provides to its licensee, and
64  * not to intellectual property embodied in modifications its licensee may
65  * make.
66  *
67  * 3.3. Redistribution of Executable. Redistribution in executable form of any
68  * substantial portion of the Covered Code or modification must reproduce the
69  * above Copyright Notice, and the following Disclaimer and Export Compliance
70  * provision in the documentation and/or other materials provided with the
71  * distribution.
72  *
73  * 3.4. Intel retains all right, title, and interest in and to the Original
74  * Intel Code.
75  *
76  * 3.5. Neither the name Intel nor any other trademark owned or controlled by
77  * Intel shall be used in advertising or otherwise to promote the sale, use or
78  * other dealings in products derived from or relating to the Covered Code
79  * without prior written authorization from Intel.
80  *
81  * 4. Disclaimer and Export Compliance
82  *
83  * 4.1. INTEL MAKES NO WARRANTY OF ANY KIND REGARDING ANY SOFTWARE PROVIDED
84  * HERE.  ANY SOFTWARE ORIGINATING FROM INTEL OR DERIVED FROM INTEL SOFTWARE
85  * IS PROVIDED "AS IS," AND INTEL WILL NOT PROVIDE ANY SUPPORT,  ASSISTANCE,
86  * INSTALLATION, TRAINING OR OTHER SERVICES.  INTEL WILL NOT PROVIDE ANY
87  * UPDATES, ENHANCEMENTS OR EXTENSIONS.  INTEL SPECIFICALLY DISCLAIMS ANY
88  * IMPLIED WARRANTIES OF MERCHANTABILITY, NONINFRINGEMENT AND FITNESS FOR A
89  * PARTICULAR PURPOSE.
90  *
91  * 4.2. IN NO EVENT SHALL INTEL HAVE ANY LIABILITY TO LICENSEE, ITS LICENSEES
92  * OR ANY OTHER THIRD PARTY, FOR ANY LOST PROFITS, LOST DATA, LOSS OF USE OR
93  * COSTS OF PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES, OR FOR ANY INDIRECT,
94  * SPECIAL OR CONSEQUENTIAL DAMAGES ARISING OUT OF THIS AGREEMENT, UNDER ANY
95  * CAUSE OF ACTION OR THEORY OF LIABILITY, AND IRRESPECTIVE OF WHETHER INTEL
96  * HAS ADVANCE NOTICE OF THE POSSIBILITY OF SUCH DAMAGES.  THESE LIMITATIONS
97  * SHALL APPLY NOTWITHSTANDING THE FAILURE OF THE ESSENTIAL PURPOSE OF ANY
98  * LIMITED REMEDY.
99  *
100  * 4.3. Licensee shall not export, either directly or indirectly, any of this
101  * software or system incorporating such software without first obtaining any
102  * required license or other approval from the U. S. Department of Commerce or
103  * any other agency or department of the United States Government.  In the
104  * event Licensee exports any such software from the United States or
105  * re-exports any such software from a foreign destination, Licensee shall
106  * ensure that the distribution and export/re-export of the software is in
107  * compliance with all laws, regulations, orders, or other restrictions of the
108  * U.S. Export Administration Regulations. Licensee agrees that neither it nor
109  * any of its subsidiaries will export/re-export any technical data, process,
110  * software, or service, directly or indirectly, to any country for which the
111  * United States government or any agency thereof requires an export license,
112  * other governmental approval, or letter of assurance, without first obtaining
113  * such license, approval or letter.
114  *
115  *****************************************************************************/
116 
117 #define __DSMETHOD_C__
118 
119 #include "acpi.h"
120 #include "amlcode.h"
121 #include "acdispat.h"
122 #include "acinterp.h"
123 #include "acnamesp.h"
124 #include "acdisasm.h"
125 
126 
127 #define _COMPONENT          ACPI_DISPATCHER
128         ACPI_MODULE_NAME    ("dsmethod")
129 
130 /* Local prototypes */
131 
132 static ACPI_STATUS
133 AcpiDsCreateMethodMutex (
134     ACPI_OPERAND_OBJECT     *MethodDesc);
135 
136 
137 /*******************************************************************************
138  *
139  * FUNCTION:    AcpiDsMethodError
140  *
141  * PARAMETERS:  Status          - Execution status
142  *              WalkState       - Current state
143  *
144  * RETURN:      Status
145  *
146  * DESCRIPTION: Called on method error. Invoke the global exception handler if
147  *              present, dump the method data if the disassembler is configured
148  *
149  *              Note: Allows the exception handler to change the status code
150  *
151  ******************************************************************************/
152 
153 ACPI_STATUS
154 AcpiDsMethodError (
155     ACPI_STATUS             Status,
156     ACPI_WALK_STATE         *WalkState)
157 {
158     ACPI_FUNCTION_ENTRY ();
159 
160 
161     /* Ignore AE_OK and control exception codes */
162 
163     if (ACPI_SUCCESS (Status) ||
164         (Status & AE_CODE_CONTROL))
165     {
166         return (Status);
167     }
168 
169     /* Invoke the global exception handler */
170 
171     if (AcpiGbl_ExceptionHandler)
172     {
173         /* Exit the interpreter, allow handler to execute methods */
174 
175         AcpiExExitInterpreter ();
176 
177         /*
178          * Handler can map the exception code to anything it wants, including
179          * AE_OK, in which case the executing method will not be aborted.
180          */
181         Status = AcpiGbl_ExceptionHandler (Status,
182                     WalkState->MethodNode ?
183                         WalkState->MethodNode->Name.Integer : 0,
184                     WalkState->Opcode, WalkState->AmlOffset, NULL);
185         AcpiExEnterInterpreter ();
186     }
187 
188     AcpiDsClearImplicitReturn (WalkState);
189 
190 #ifdef ACPI_DISASSEMBLER
191     if (ACPI_FAILURE (Status))
192     {
193         /* Display method locals/args if disassembler is present */
194 
195         AcpiDmDumpMethodInfo (Status, WalkState, WalkState->Op);
196     }
197 #endif
198 
199     return (Status);
200 }
201 
202 
203 /*******************************************************************************
204  *
205  * FUNCTION:    AcpiDsCreateMethodMutex
206  *
207  * PARAMETERS:  ObjDesc             - The method object
208  *
209  * RETURN:      Status
210  *
211  * DESCRIPTION: Create a mutex object for a serialized control method
212  *
213  ******************************************************************************/
214 
215 static ACPI_STATUS
216 AcpiDsCreateMethodMutex (
217     ACPI_OPERAND_OBJECT     *MethodDesc)
218 {
219     ACPI_OPERAND_OBJECT     *MutexDesc;
220     ACPI_STATUS             Status;
221 
222 
223     ACPI_FUNCTION_TRACE (DsCreateMethodMutex);
224 
225 
226     /* Create the new mutex object */
227 
228     MutexDesc = AcpiUtCreateInternalObject (ACPI_TYPE_MUTEX);
229     if (!MutexDesc)
230     {
231         return_ACPI_STATUS (AE_NO_MEMORY);
232     }
233 
234     /* Create the actual OS Mutex */
235 
236     Status = AcpiOsCreateMutex (&MutexDesc->Mutex.OsMutex);
237     if (ACPI_FAILURE (Status))
238     {
239         return_ACPI_STATUS (Status);
240     }
241 
242     MutexDesc->Mutex.SyncLevel = MethodDesc->Method.SyncLevel;
243     MethodDesc->Method.Mutex = MutexDesc;
244     return_ACPI_STATUS (AE_OK);
245 }
246 
247 
248 /*******************************************************************************
249  *
250  * FUNCTION:    AcpiDsBeginMethodExecution
251  *
252  * PARAMETERS:  MethodNode          - Node of the method
253  *              ObjDesc             - The method object
254  *              WalkState           - current state, NULL if not yet executing
255  *                                    a method.
256  *
257  * RETURN:      Status
258  *
259  * DESCRIPTION: Prepare a method for execution.  Parses the method if necessary,
260  *              increments the thread count, and waits at the method semaphore
261  *              for clearance to execute.
262  *
263  ******************************************************************************/
264 
265 ACPI_STATUS
266 AcpiDsBeginMethodExecution (
267     ACPI_NAMESPACE_NODE     *MethodNode,
268     ACPI_OPERAND_OBJECT     *ObjDesc,
269     ACPI_WALK_STATE         *WalkState)
270 {
271     ACPI_STATUS             Status = AE_OK;
272 
273 
274     ACPI_FUNCTION_TRACE_PTR (DsBeginMethodExecution, MethodNode);
275 
276 
277     if (!MethodNode)
278     {
279         return_ACPI_STATUS (AE_NULL_ENTRY);
280     }
281 
282     /* Prevent wraparound of thread count */
283 
284     if (ObjDesc->Method.ThreadCount == ACPI_UINT8_MAX)
285     {
286         ACPI_ERROR ((AE_INFO,
287             "Method reached maximum reentrancy limit (255)"));
288         return_ACPI_STATUS (AE_AML_METHOD_LIMIT);
289     }
290 
291     /*
292      * If this method is serialized, we need to acquire the method mutex.
293      */
294     if (ObjDesc->Method.MethodFlags & AML_METHOD_SERIALIZED)
295     {
296         /*
297          * Create a mutex for the method if it is defined to be Serialized
298          * and a mutex has not already been created. We defer the mutex creation
299          * until a method is actually executed, to minimize the object count
300          */
301         if (!ObjDesc->Method.Mutex)
302         {
303             Status = AcpiDsCreateMethodMutex (ObjDesc);
304             if (ACPI_FAILURE (Status))
305             {
306                 return_ACPI_STATUS (Status);
307             }
308         }
309 
310         /*
311          * The CurrentSyncLevel (per-thread) must be less than or equal to
312          * the sync level of the method. This mechanism provides some
313          * deadlock prevention
314          *
315          * Top-level method invocation has no walk state at this point
316          */
317         if (WalkState &&
318             (WalkState->Thread->CurrentSyncLevel > ObjDesc->Method.Mutex->Mutex.SyncLevel))
319         {
320             ACPI_ERROR ((AE_INFO,
321                 "Cannot acquire Mutex for method [%4.4s], current SyncLevel is too large (%d)",
322                 AcpiUtGetNodeName (MethodNode),
323                 WalkState->Thread->CurrentSyncLevel));
324 
325             return_ACPI_STATUS (AE_AML_MUTEX_ORDER);
326         }
327 
328         /*
329          * Obtain the method mutex if necessary. Do not acquire mutex for a
330          * recursive call.
331          */
332         if (!WalkState ||
333             !ObjDesc->Method.Mutex->Mutex.ThreadId ||
334             (WalkState->Thread->ThreadId != ObjDesc->Method.Mutex->Mutex.ThreadId))
335         {
336             /*
337              * Acquire the method mutex. This releases the interpreter if we
338              * block (and reacquires it before it returns)
339              */
340             Status = AcpiExSystemWaitMutex (ObjDesc->Method.Mutex->Mutex.OsMutex,
341                         ACPI_WAIT_FOREVER);
342             if (ACPI_FAILURE (Status))
343             {
344                 return_ACPI_STATUS (Status);
345             }
346 
347             /* Update the mutex and walk info and save the original SyncLevel */
348 
349             if (WalkState)
350             {
351                 ObjDesc->Method.Mutex->Mutex.OriginalSyncLevel =
352                     WalkState->Thread->CurrentSyncLevel;
353 
354                 ObjDesc->Method.Mutex->Mutex.ThreadId = WalkState->Thread->ThreadId;
355                 WalkState->Thread->CurrentSyncLevel = ObjDesc->Method.SyncLevel;
356             }
357             else
358             {
359                 ObjDesc->Method.Mutex->Mutex.OriginalSyncLevel =
360                     ObjDesc->Method.Mutex->Mutex.SyncLevel;
361             }
362         }
363 
364         /* Always increase acquisition depth */
365 
366         ObjDesc->Method.Mutex->Mutex.AcquisitionDepth++;
367     }
368 
369     /*
370      * Allocate an Owner ID for this method, only if this is the first thread
371      * to begin concurrent execution. We only need one OwnerId, even if the
372      * method is invoked recursively.
373      */
374     if (!ObjDesc->Method.OwnerId)
375     {
376         Status = AcpiUtAllocateOwnerId (&ObjDesc->Method.OwnerId);
377         if (ACPI_FAILURE (Status))
378         {
379             goto Cleanup;
380         }
381     }
382 
383     /*
384      * Increment the method parse tree thread count since it has been
385      * reentered one more time (even if it is the same thread)
386      */
387     ObjDesc->Method.ThreadCount++;
388     AcpiMethodCount++;
389     return_ACPI_STATUS (Status);
390 
391 
392 Cleanup:
393     /* On error, must release the method mutex (if present) */
394 
395     if (ObjDesc->Method.Mutex)
396     {
397         AcpiOsReleaseMutex (ObjDesc->Method.Mutex->Mutex.OsMutex);
398     }
399     return_ACPI_STATUS (Status);
400 }
401 
402 
403 /*******************************************************************************
404  *
405  * FUNCTION:    AcpiDsCallControlMethod
406  *
407  * PARAMETERS:  Thread              - Info for this thread
408  *              ThisWalkState       - Current walk state
409  *              Op                  - Current Op to be walked
410  *
411  * RETURN:      Status
412  *
413  * DESCRIPTION: Transfer execution to a called control method
414  *
415  ******************************************************************************/
416 
417 ACPI_STATUS
418 AcpiDsCallControlMethod (
419     ACPI_THREAD_STATE       *Thread,
420     ACPI_WALK_STATE         *ThisWalkState,
421     ACPI_PARSE_OBJECT       *Op)
422 {
423     ACPI_STATUS             Status;
424     ACPI_NAMESPACE_NODE     *MethodNode;
425     ACPI_WALK_STATE         *NextWalkState = NULL;
426     ACPI_OPERAND_OBJECT     *ObjDesc;
427     ACPI_EVALUATE_INFO      *Info;
428     UINT32                  i;
429 
430 
431     ACPI_FUNCTION_TRACE_PTR (DsCallControlMethod, ThisWalkState);
432 
433     ACPI_DEBUG_PRINT ((ACPI_DB_DISPATCH, "Calling method %p, currentstate=%p\n",
434         ThisWalkState->PrevOp, ThisWalkState));
435 
436     /*
437      * Get the namespace entry for the control method we are about to call
438      */
439     MethodNode = ThisWalkState->MethodCallNode;
440     if (!MethodNode)
441     {
442         return_ACPI_STATUS (AE_NULL_ENTRY);
443     }
444 
445     ObjDesc = AcpiNsGetAttachedObject (MethodNode);
446     if (!ObjDesc)
447     {
448         return_ACPI_STATUS (AE_NULL_OBJECT);
449     }
450 
451     /* Init for new method, possibly wait on method mutex */
452 
453     Status = AcpiDsBeginMethodExecution (MethodNode, ObjDesc,
454                 ThisWalkState);
455     if (ACPI_FAILURE (Status))
456     {
457         return_ACPI_STATUS (Status);
458     }
459 
460     /* Begin method parse/execution. Create a new walk state */
461 
462     NextWalkState = AcpiDsCreateWalkState (ObjDesc->Method.OwnerId,
463                         NULL, ObjDesc, Thread);
464     if (!NextWalkState)
465     {
466         Status = AE_NO_MEMORY;
467         goto Cleanup;
468     }
469 
470     /*
471      * The resolved arguments were put on the previous walk state's operand
472      * stack. Operands on the previous walk state stack always
473      * start at index 0. Also, null terminate the list of arguments
474      */
475     ThisWalkState->Operands [ThisWalkState->NumOperands] = NULL;
476 
477     /*
478      * Allocate and initialize the evaluation information block
479      * TBD: this is somewhat inefficient, should change interface to
480      * DsInitAmlWalk. For now, keeps this struct off the CPU stack
481      */
482     Info = ACPI_ALLOCATE_ZEROED (sizeof (ACPI_EVALUATE_INFO));
483     if (!Info)
484     {
485         return_ACPI_STATUS (AE_NO_MEMORY);
486     }
487 
488     Info->Parameters = &ThisWalkState->Operands[0];
489 
490     Status = AcpiDsInitAmlWalk (NextWalkState, NULL, MethodNode,
491                 ObjDesc->Method.AmlStart, ObjDesc->Method.AmlLength,
492                 Info, ACPI_IMODE_EXECUTE);
493 
494     ACPI_FREE (Info);
495     if (ACPI_FAILURE (Status))
496     {
497         goto Cleanup;
498     }
499 
500     /*
501      * Delete the operands on the previous walkstate operand stack
502      * (they were copied to new objects)
503      */
504     for (i = 0; i < ObjDesc->Method.ParamCount; i++)
505     {
506         AcpiUtRemoveReference (ThisWalkState->Operands [i]);
507         ThisWalkState->Operands [i] = NULL;
508     }
509 
510     /* Clear the operand stack */
511 
512     ThisWalkState->NumOperands = 0;
513 
514     ACPI_DEBUG_PRINT ((ACPI_DB_DISPATCH,
515         "**** Begin nested execution of [%4.4s] **** WalkState=%p\n",
516         MethodNode->Name.Ascii, NextWalkState));
517 
518     /* Invoke an internal method if necessary */
519 
520     if (ObjDesc->Method.MethodFlags & AML_METHOD_INTERNAL_ONLY)
521     {
522         Status = ObjDesc->Method.Implementation (NextWalkState);
523     }
524 
525     return_ACPI_STATUS (Status);
526 
527 
528 Cleanup:
529 
530     /* On error, we must terminate the method properly */
531 
532     AcpiDsTerminateControlMethod (ObjDesc, NextWalkState);
533     if (NextWalkState)
534     {
535         AcpiDsDeleteWalkState (NextWalkState);
536     }
537 
538     return_ACPI_STATUS (Status);
539 }
540 
541 
542 /*******************************************************************************
543  *
544  * FUNCTION:    AcpiDsRestartControlMethod
545  *
546  * PARAMETERS:  WalkState           - State for preempted method (caller)
547  *              ReturnDesc          - Return value from the called method
548  *
549  * RETURN:      Status
550  *
551  * DESCRIPTION: Restart a method that was preempted by another (nested) method
552  *              invocation.  Handle the return value (if any) from the callee.
553  *
554  ******************************************************************************/
555 
556 ACPI_STATUS
557 AcpiDsRestartControlMethod (
558     ACPI_WALK_STATE         *WalkState,
559     ACPI_OPERAND_OBJECT     *ReturnDesc)
560 {
561     ACPI_STATUS             Status;
562     int                     SameAsImplicitReturn;
563 
564 
565     ACPI_FUNCTION_TRACE_PTR (DsRestartControlMethod, WalkState);
566 
567 
568     ACPI_DEBUG_PRINT ((ACPI_DB_DISPATCH,
569         "****Restart [%4.4s] Op %p ReturnValueFromCallee %p\n",
570         AcpiUtGetNodeName (WalkState->MethodNode),
571         WalkState->MethodCallOp, ReturnDesc));
572 
573     ACPI_DEBUG_PRINT ((ACPI_DB_DISPATCH,
574         "    ReturnFromThisMethodUsed?=%X ResStack %p Walk %p\n",
575         WalkState->ReturnUsed,
576         WalkState->Results, WalkState));
577 
578     /* Did the called method return a value? */
579 
580     if (ReturnDesc)
581     {
582         /* Is the implicit return object the same as the return desc? */
583 
584         SameAsImplicitReturn = (WalkState->ImplicitReturnObj == ReturnDesc);
585 
586         /* Are we actually going to use the return value? */
587 
588         if (WalkState->ReturnUsed)
589         {
590             /* Save the return value from the previous method */
591 
592             Status = AcpiDsResultPush (ReturnDesc, WalkState);
593             if (ACPI_FAILURE (Status))
594             {
595                 AcpiUtRemoveReference (ReturnDesc);
596                 return_ACPI_STATUS (Status);
597             }
598 
599             /*
600              * Save as THIS method's return value in case it is returned
601              * immediately to yet another method
602              */
603             WalkState->ReturnDesc = ReturnDesc;
604         }
605 
606         /*
607          * The following code is the optional support for the so-called
608          * "implicit return". Some AML code assumes that the last value of the
609          * method is "implicitly" returned to the caller, in the absence of an
610          * explicit return value.
611          *
612          * Just save the last result of the method as the return value.
613          *
614          * NOTE: this is optional because the ASL language does not actually
615          * support this behavior.
616          */
617         else if (!AcpiDsDoImplicitReturn (ReturnDesc, WalkState, FALSE) ||
618                  SameAsImplicitReturn)
619         {
620             /*
621              * Delete the return value if it will not be used by the
622              * calling method or remove one reference if the explicit return
623              * is the same as the implicit return value.
624              */
625             AcpiUtRemoveReference (ReturnDesc);
626         }
627     }
628 
629     return_ACPI_STATUS (AE_OK);
630 }
631 
632 
633 /*******************************************************************************
634  *
635  * FUNCTION:    AcpiDsTerminateControlMethod
636  *
637  * PARAMETERS:  MethodDesc          - Method object
638  *              WalkState           - State associated with the method
639  *
640  * RETURN:      None
641  *
642  * DESCRIPTION: Terminate a control method.  Delete everything that the method
643  *              created, delete all locals and arguments, and delete the parse
644  *              tree if requested.
645  *
646  * MUTEX:       Interpreter is locked
647  *
648  ******************************************************************************/
649 
650 void
651 AcpiDsTerminateControlMethod (
652     ACPI_OPERAND_OBJECT     *MethodDesc,
653     ACPI_WALK_STATE         *WalkState)
654 {
655 
656     ACPI_FUNCTION_TRACE_PTR (DsTerminateControlMethod, WalkState);
657 
658 
659     /* MethodDesc is required, WalkState is optional */
660 
661     if (!MethodDesc)
662     {
663         return_VOID;
664     }
665 
666     if (WalkState)
667     {
668         /* Delete all arguments and locals */
669 
670         AcpiDsMethodDataDeleteAll (WalkState);
671 
672         /*
673          * If method is serialized, release the mutex and restore the
674          * current sync level for this thread
675          */
676         if (MethodDesc->Method.Mutex)
677         {
678             /* Acquisition Depth handles recursive calls */
679 
680             MethodDesc->Method.Mutex->Mutex.AcquisitionDepth--;
681             if (!MethodDesc->Method.Mutex->Mutex.AcquisitionDepth)
682             {
683                 WalkState->Thread->CurrentSyncLevel =
684                     MethodDesc->Method.Mutex->Mutex.OriginalSyncLevel;
685 
686                 AcpiOsReleaseMutex (MethodDesc->Method.Mutex->Mutex.OsMutex);
687                 MethodDesc->Method.Mutex->Mutex.ThreadId = 0;
688             }
689         }
690 
691         /*
692          * Delete any namespace objects created anywhere within
693          * the namespace by the execution of this method
694          */
695         AcpiNsDeleteNamespaceByOwner (MethodDesc->Method.OwnerId);
696     }
697 
698     /* Decrement the thread count on the method */
699 
700     if (MethodDesc->Method.ThreadCount)
701     {
702         MethodDesc->Method.ThreadCount--;
703     }
704     else
705     {
706         ACPI_ERROR ((AE_INFO,
707             "Invalid zero thread count in method"));
708     }
709 
710     /* Are there any other threads currently executing this method? */
711 
712     if (MethodDesc->Method.ThreadCount)
713     {
714         /*
715          * Additional threads. Do not release the OwnerId in this case,
716          * we immediately reuse it for the next thread executing this method
717          */
718         ACPI_DEBUG_PRINT ((ACPI_DB_DISPATCH,
719             "*** Completed execution of one thread, %d threads remaining\n",
720             MethodDesc->Method.ThreadCount));
721     }
722     else
723     {
724         /* This is the only executing thread for this method */
725 
726         /*
727          * Support to dynamically change a method from NotSerialized to
728          * Serialized if it appears that the method is incorrectly written and
729          * does not support multiple thread execution. The best example of this
730          * is if such a method creates namespace objects and blocks. A second
731          * thread will fail with an AE_ALREADY_EXISTS exception
732          *
733          * This code is here because we must wait until the last thread exits
734          * before creating the synchronization semaphore.
735          */
736         if ((MethodDesc->Method.MethodFlags & AML_METHOD_SERIALIZED) &&
737             (!MethodDesc->Method.Mutex))
738         {
739             (void) AcpiDsCreateMethodMutex (MethodDesc);
740         }
741 
742         /* No more threads, we can free the OwnerId */
743 
744         AcpiUtReleaseOwnerId (&MethodDesc->Method.OwnerId);
745     }
746 
747     return_VOID;
748 }
749 
750 
751