xref: /freebsd/sys/contrib/dev/acpica/components/utilities/utosi.c (revision d93a896ef95946b0bf1219866fcb324b78543444)
1 /******************************************************************************
2  *
3  * Module Name: utosi - Support for the _OSI predefined control method
4  *
5  *****************************************************************************/
6 
7 /******************************************************************************
8  *
9  * 1. Copyright Notice
10  *
11  * Some or all of this work - Copyright (c) 1999 - 2017, Intel Corp.
12  * All rights reserved.
13  *
14  * 2. License
15  *
16  * 2.1. This is your license from Intel Corp. under its intellectual property
17  * rights. You may have additional license terms from the party that provided
18  * you this software, covering your right to use that party's intellectual
19  * property rights.
20  *
21  * 2.2. Intel grants, free of charge, to any person ("Licensee") obtaining a
22  * copy of the source code appearing in this file ("Covered Code") an
23  * irrevocable, perpetual, worldwide license under Intel's copyrights in the
24  * base code distributed originally by Intel ("Original Intel Code") to copy,
25  * make derivatives, distribute, use and display any portion of the Covered
26  * Code in any form, with the right to sublicense such rights; and
27  *
28  * 2.3. Intel grants Licensee a non-exclusive and non-transferable patent
29  * license (with the right to sublicense), under only those claims of Intel
30  * patents that are infringed by the Original Intel Code, to make, use, sell,
31  * offer to sell, and import the Covered Code and derivative works thereof
32  * solely to the minimum extent necessary to exercise the above copyright
33  * license, and in no event shall the patent license extend to any additions
34  * to or modifications of the Original Intel Code. No other license or right
35  * is granted directly or by implication, estoppel or otherwise;
36  *
37  * The above copyright and patent license is granted only if the following
38  * conditions are met:
39  *
40  * 3. Conditions
41  *
42  * 3.1. Redistribution of Source with Rights to Further Distribute Source.
43  * Redistribution of source code of any substantial portion of the Covered
44  * Code or modification with rights to further distribute source must include
45  * the above Copyright Notice, the above License, this list of Conditions,
46  * and the following Disclaimer and Export Compliance provision. In addition,
47  * Licensee must cause all Covered Code to which Licensee contributes to
48  * contain a file documenting the changes Licensee made to create that Covered
49  * Code and the date of any change. Licensee must include in that file the
50  * documentation of any changes made by any predecessor Licensee. Licensee
51  * must include a prominent statement that the modification is derived,
52  * directly or indirectly, from Original Intel Code.
53  *
54  * 3.2. Redistribution of Source with no Rights to Further Distribute Source.
55  * Redistribution of source code of any substantial portion of the Covered
56  * Code or modification without rights to further distribute source must
57  * include the following Disclaimer and Export Compliance provision in the
58  * documentation and/or other materials provided with distribution. In
59  * addition, Licensee may not authorize further sublicense of source of any
60  * portion of the Covered Code, and must include terms to the effect that the
61  * license from Licensee to its licensee is limited to the intellectual
62  * property embodied in the software Licensee provides to its licensee, and
63  * not to intellectual property embodied in modifications its licensee may
64  * make.
65  *
66  * 3.3. Redistribution of Executable. Redistribution in executable form of any
67  * substantial portion of the Covered Code or modification must reproduce the
68  * above Copyright Notice, and the following Disclaimer and Export Compliance
69  * provision in the documentation and/or other materials provided with the
70  * distribution.
71  *
72  * 3.4. Intel retains all right, title, and interest in and to the Original
73  * Intel Code.
74  *
75  * 3.5. Neither the name Intel nor any other trademark owned or controlled by
76  * Intel shall be used in advertising or otherwise to promote the sale, use or
77  * other dealings in products derived from or relating to the Covered Code
78  * without prior written authorization from Intel.
79  *
80  * 4. Disclaimer and Export Compliance
81  *
82  * 4.1. INTEL MAKES NO WARRANTY OF ANY KIND REGARDING ANY SOFTWARE PROVIDED
83  * HERE. ANY SOFTWARE ORIGINATING FROM INTEL OR DERIVED FROM INTEL SOFTWARE
84  * IS PROVIDED "AS IS," AND INTEL WILL NOT PROVIDE ANY SUPPORT, ASSISTANCE,
85  * INSTALLATION, TRAINING OR OTHER SERVICES. INTEL WILL NOT PROVIDE ANY
86  * UPDATES, ENHANCEMENTS OR EXTENSIONS. INTEL SPECIFICALLY DISCLAIMS ANY
87  * IMPLIED WARRANTIES OF MERCHANTABILITY, NONINFRINGEMENT AND FITNESS FOR A
88  * PARTICULAR PURPOSE.
89  *
90  * 4.2. IN NO EVENT SHALL INTEL HAVE ANY LIABILITY TO LICENSEE, ITS LICENSEES
91  * OR ANY OTHER THIRD PARTY, FOR ANY LOST PROFITS, LOST DATA, LOSS OF USE OR
92  * COSTS OF PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES, OR FOR ANY INDIRECT,
93  * SPECIAL OR CONSEQUENTIAL DAMAGES ARISING OUT OF THIS AGREEMENT, UNDER ANY
94  * CAUSE OF ACTION OR THEORY OF LIABILITY, AND IRRESPECTIVE OF WHETHER INTEL
95  * HAS ADVANCE NOTICE OF THE POSSIBILITY OF SUCH DAMAGES. THESE LIMITATIONS
96  * SHALL APPLY NOTWITHSTANDING THE FAILURE OF THE ESSENTIAL PURPOSE OF ANY
97  * LIMITED REMEDY.
98  *
99  * 4.3. Licensee shall not export, either directly or indirectly, any of this
100  * software or system incorporating such software without first obtaining any
101  * required license or other approval from the U. S. Department of Commerce or
102  * any other agency or department of the United States Government. In the
103  * event Licensee exports any such software from the United States or
104  * re-exports any such software from a foreign destination, Licensee shall
105  * ensure that the distribution and export/re-export of the software is in
106  * compliance with all laws, regulations, orders, or other restrictions of the
107  * U.S. Export Administration Regulations. Licensee agrees that neither it nor
108  * any of its subsidiaries will export/re-export any technical data, process,
109  * software, or service, directly or indirectly, to any country for which the
110  * United States government or any agency thereof requires an export license,
111  * other governmental approval, or letter of assurance, without first obtaining
112  * such license, approval or letter.
113  *
114  *****************************************************************************
115  *
116  * Alternatively, you may choose to be licensed under the terms of the
117  * following license:
118  *
119  * Redistribution and use in source and binary forms, with or without
120  * modification, are permitted provided that the following conditions
121  * are met:
122  * 1. Redistributions of source code must retain the above copyright
123  *    notice, this list of conditions, and the following disclaimer,
124  *    without modification.
125  * 2. Redistributions in binary form must reproduce at minimum a disclaimer
126  *    substantially similar to the "NO WARRANTY" disclaimer below
127  *    ("Disclaimer") and any redistribution must be conditioned upon
128  *    including a substantially similar Disclaimer requirement for further
129  *    binary redistribution.
130  * 3. Neither the names of the above-listed copyright holders nor the names
131  *    of any contributors may be used to endorse or promote products derived
132  *    from this software without specific prior written permission.
133  *
134  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
135  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
136  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
137  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
138  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
139  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
140  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
141  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
142  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
143  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
144  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
145  *
146  * Alternatively, you may choose to be licensed under the terms of the
147  * GNU General Public License ("GPL") version 2 as published by the Free
148  * Software Foundation.
149  *
150  *****************************************************************************/
151 
152 #include <contrib/dev/acpica/include/acpi.h>
153 #include <contrib/dev/acpica/include/accommon.h>
154 
155 
156 #define _COMPONENT          ACPI_UTILITIES
157         ACPI_MODULE_NAME    ("utosi")
158 
159 
160 /******************************************************************************
161  *
162  * ACPICA policy for new _OSI strings:
163  *
164  * It is the stated policy of ACPICA that new _OSI strings will be integrated
165  * into this module as soon as possible after they are defined. It is strongly
166  * recommended that all ACPICA hosts mirror this policy and integrate any
167  * changes to this module as soon as possible. There are several historical
168  * reasons behind this policy:
169  *
170  * 1) New BIOSs tend to test only the case where the host responds TRUE to
171  *    the latest version of Windows, which would respond to the latest/newest
172  *    _OSI string. Not responding TRUE to the latest version of Windows will
173  *    risk executing untested code paths throughout the DSDT and SSDTs.
174  *
175  * 2) If a new _OSI string is recognized only after a significant delay, this
176  *    has the potential to cause problems on existing working machines because
177  *    of the possibility that a new and different path through the ASL code
178  *    will be executed.
179  *
180  * 3) New _OSI strings are tending to come out about once per year. A delay
181  *    in recognizing a new string for a significant amount of time risks the
182  *    release of another string which only compounds the initial problem.
183  *
184  *****************************************************************************/
185 
186 
187 /*
188  * Strings supported by the _OSI predefined control method (which is
189  * implemented internally within this module.)
190  *
191  * March 2009: Removed "Linux" as this host no longer wants to respond true
192  * for this string. Basically, the only safe OS strings are windows-related
193  * and in many or most cases represent the only test path within the
194  * BIOS-provided ASL code.
195  *
196  * The last element of each entry is used to track the newest version of
197  * Windows that the BIOS has requested.
198  */
199 static ACPI_INTERFACE_INFO    AcpiDefaultSupportedInterfaces[] =
200 {
201     /* Operating System Vendor Strings */
202 
203     {"Windows 2000",        NULL, 0, ACPI_OSI_WIN_2000},         /* Windows 2000 */
204     {"Windows 2001",        NULL, 0, ACPI_OSI_WIN_XP},           /* Windows XP */
205     {"Windows 2001 SP1",    NULL, 0, ACPI_OSI_WIN_XP_SP1},       /* Windows XP SP1 */
206     {"Windows 2001.1",      NULL, 0, ACPI_OSI_WINSRV_2003},      /* Windows Server 2003 */
207     {"Windows 2001 SP2",    NULL, 0, ACPI_OSI_WIN_XP_SP2},       /* Windows XP SP2 */
208     {"Windows 2001.1 SP1",  NULL, 0, ACPI_OSI_WINSRV_2003_SP1},  /* Windows Server 2003 SP1 - Added 03/2006 */
209     {"Windows 2006",        NULL, 0, ACPI_OSI_WIN_VISTA},        /* Windows Vista - Added 03/2006 */
210     {"Windows 2006.1",      NULL, 0, ACPI_OSI_WINSRV_2008},      /* Windows Server 2008 - Added 09/2009 */
211     {"Windows 2006 SP1",    NULL, 0, ACPI_OSI_WIN_VISTA_SP1},    /* Windows Vista SP1 - Added 09/2009 */
212     {"Windows 2006 SP2",    NULL, 0, ACPI_OSI_WIN_VISTA_SP2},    /* Windows Vista SP2 - Added 09/2010 */
213     {"Windows 2009",        NULL, 0, ACPI_OSI_WIN_7},            /* Windows 7 and Server 2008 R2 - Added 09/2009 */
214     {"Windows 2012",        NULL, 0, ACPI_OSI_WIN_8},            /* Windows 8 and Server 2012 - Added 08/2012 */
215     {"Windows 2013",        NULL, 0, ACPI_OSI_WIN_8},            /* Windows 8.1 and Server 2012 R2 - Added 01/2014 */
216     {"Windows 2015",        NULL, 0, ACPI_OSI_WIN_10},           /* Windows 10 - Added 03/2015 */
217 
218     /* Feature Group Strings */
219 
220     {"Extended Address Space Descriptor", NULL, ACPI_OSI_FEATURE, 0},
221 
222     /*
223      * All "optional" feature group strings (features that are implemented
224      * by the host) should be dynamically modified to VALID by the host via
225      * AcpiInstallInterface or AcpiUpdateInterfaces. Such optional feature
226      * group strings are set as INVALID by default here.
227      */
228 
229     {"Module Device",               NULL, ACPI_OSI_OPTIONAL_FEATURE, 0},
230     {"Processor Device",            NULL, ACPI_OSI_OPTIONAL_FEATURE, 0},
231     {"3.0 Thermal Model",           NULL, ACPI_OSI_OPTIONAL_FEATURE, 0},
232     {"3.0 _SCP Extensions",         NULL, ACPI_OSI_OPTIONAL_FEATURE, 0},
233     {"Processor Aggregator Device", NULL, ACPI_OSI_OPTIONAL_FEATURE, 0}
234 };
235 
236 
237 /*******************************************************************************
238  *
239  * FUNCTION:    AcpiUtInitializeInterfaces
240  *
241  * PARAMETERS:  None
242  *
243  * RETURN:      Status
244  *
245  * DESCRIPTION: Initialize the global _OSI supported interfaces list
246  *
247  ******************************************************************************/
248 
249 ACPI_STATUS
250 AcpiUtInitializeInterfaces (
251     void)
252 {
253     ACPI_STATUS             Status;
254     UINT32                  i;
255 
256 
257     Status = AcpiOsAcquireMutex (AcpiGbl_OsiMutex, ACPI_WAIT_FOREVER);
258     if (ACPI_FAILURE (Status))
259     {
260         return (Status);
261     }
262 
263     AcpiGbl_SupportedInterfaces = AcpiDefaultSupportedInterfaces;
264 
265     /* Link the static list of supported interfaces */
266 
267     for (i = 0;
268         i < (ACPI_ARRAY_LENGTH (AcpiDefaultSupportedInterfaces) - 1);
269         i++)
270     {
271         AcpiDefaultSupportedInterfaces[i].Next =
272             &AcpiDefaultSupportedInterfaces[(ACPI_SIZE) i + 1];
273     }
274 
275     AcpiOsReleaseMutex (AcpiGbl_OsiMutex);
276     return (AE_OK);
277 }
278 
279 
280 /*******************************************************************************
281  *
282  * FUNCTION:    AcpiUtInterfaceTerminate
283  *
284  * PARAMETERS:  None
285  *
286  * RETURN:      Status
287  *
288  * DESCRIPTION: Delete all interfaces in the global list. Sets
289  *              AcpiGbl_SupportedInterfaces to NULL.
290  *
291  ******************************************************************************/
292 
293 ACPI_STATUS
294 AcpiUtInterfaceTerminate (
295     void)
296 {
297     ACPI_STATUS             Status;
298     ACPI_INTERFACE_INFO     *NextInterface;
299 
300 
301     Status = AcpiOsAcquireMutex (AcpiGbl_OsiMutex, ACPI_WAIT_FOREVER);
302     if (ACPI_FAILURE (Status))
303     {
304         return (Status);
305     }
306 
307     NextInterface = AcpiGbl_SupportedInterfaces;
308     while (NextInterface)
309     {
310         AcpiGbl_SupportedInterfaces = NextInterface->Next;
311 
312         if (NextInterface->Flags & ACPI_OSI_DYNAMIC)
313         {
314             /* Only interfaces added at runtime can be freed */
315 
316             ACPI_FREE (NextInterface->Name);
317             ACPI_FREE (NextInterface);
318         }
319         else
320         {
321             /* Interface is in static list. Reset it to invalid or valid. */
322 
323             if (NextInterface->Flags & ACPI_OSI_DEFAULT_INVALID)
324             {
325                 NextInterface->Flags |= ACPI_OSI_INVALID;
326             }
327             else
328             {
329                 NextInterface->Flags &= ~ACPI_OSI_INVALID;
330             }
331         }
332 
333         NextInterface = AcpiGbl_SupportedInterfaces;
334     }
335 
336     AcpiOsReleaseMutex (AcpiGbl_OsiMutex);
337     return (AE_OK);
338 }
339 
340 
341 /*******************************************************************************
342  *
343  * FUNCTION:    AcpiUtInstallInterface
344  *
345  * PARAMETERS:  InterfaceName       - The interface to install
346  *
347  * RETURN:      Status
348  *
349  * DESCRIPTION: Install the interface into the global interface list.
350  *              Caller MUST hold AcpiGbl_OsiMutex
351  *
352  ******************************************************************************/
353 
354 ACPI_STATUS
355 AcpiUtInstallInterface (
356     ACPI_STRING             InterfaceName)
357 {
358     ACPI_INTERFACE_INFO     *InterfaceInfo;
359 
360 
361     /* Allocate info block and space for the name string */
362 
363     InterfaceInfo = ACPI_ALLOCATE_ZEROED (sizeof (ACPI_INTERFACE_INFO));
364     if (!InterfaceInfo)
365     {
366         return (AE_NO_MEMORY);
367     }
368 
369     InterfaceInfo->Name = ACPI_ALLOCATE_ZEROED (strlen (InterfaceName) + 1);
370     if (!InterfaceInfo->Name)
371     {
372         ACPI_FREE (InterfaceInfo);
373         return (AE_NO_MEMORY);
374     }
375 
376     /* Initialize new info and insert at the head of the global list */
377 
378     strcpy (InterfaceInfo->Name, InterfaceName);
379     InterfaceInfo->Flags = ACPI_OSI_DYNAMIC;
380     InterfaceInfo->Next = AcpiGbl_SupportedInterfaces;
381 
382     AcpiGbl_SupportedInterfaces = InterfaceInfo;
383     return (AE_OK);
384 }
385 
386 
387 /*******************************************************************************
388  *
389  * FUNCTION:    AcpiUtRemoveInterface
390  *
391  * PARAMETERS:  InterfaceName       - The interface to remove
392  *
393  * RETURN:      Status
394  *
395  * DESCRIPTION: Remove the interface from the global interface list.
396  *              Caller MUST hold AcpiGbl_OsiMutex
397  *
398  ******************************************************************************/
399 
400 ACPI_STATUS
401 AcpiUtRemoveInterface (
402     ACPI_STRING             InterfaceName)
403 {
404     ACPI_INTERFACE_INFO     *PreviousInterface;
405     ACPI_INTERFACE_INFO     *NextInterface;
406 
407 
408     PreviousInterface = NextInterface = AcpiGbl_SupportedInterfaces;
409     while (NextInterface)
410     {
411         if (!strcmp (InterfaceName, NextInterface->Name))
412         {
413             /*
414              * Found: name is in either the static list
415              * or was added at runtime
416              */
417             if (NextInterface->Flags & ACPI_OSI_DYNAMIC)
418             {
419                 /* Interface was added dynamically, remove and free it */
420 
421                 if (PreviousInterface == NextInterface)
422                 {
423                     AcpiGbl_SupportedInterfaces = NextInterface->Next;
424                 }
425                 else
426                 {
427                     PreviousInterface->Next = NextInterface->Next;
428                 }
429 
430                 ACPI_FREE (NextInterface->Name);
431                 ACPI_FREE (NextInterface);
432             }
433             else
434             {
435                 /*
436                  * Interface is in static list. If marked invalid, then
437                  * it does not actually exist. Else, mark it invalid.
438                  */
439                 if (NextInterface->Flags & ACPI_OSI_INVALID)
440                 {
441                     return (AE_NOT_EXIST);
442                 }
443 
444                 NextInterface->Flags |= ACPI_OSI_INVALID;
445             }
446 
447             return (AE_OK);
448         }
449 
450         PreviousInterface = NextInterface;
451         NextInterface = NextInterface->Next;
452     }
453 
454     /* Interface was not found */
455 
456     return (AE_NOT_EXIST);
457 }
458 
459 
460 /*******************************************************************************
461  *
462  * FUNCTION:    AcpiUtUpdateInterfaces
463  *
464  * PARAMETERS:  Action              - Actions to be performed during the
465  *                                    update
466  *
467  * RETURN:      Status
468  *
469  * DESCRIPTION: Update _OSI interface strings, disabling or enabling OS vendor
470  *              strings or/and feature group strings.
471  *              Caller MUST hold AcpiGbl_OsiMutex
472  *
473  ******************************************************************************/
474 
475 ACPI_STATUS
476 AcpiUtUpdateInterfaces (
477     UINT8                   Action)
478 {
479     ACPI_INTERFACE_INFO     *NextInterface;
480 
481 
482     NextInterface = AcpiGbl_SupportedInterfaces;
483     while (NextInterface)
484     {
485         if (((NextInterface->Flags & ACPI_OSI_FEATURE) &&
486              (Action & ACPI_FEATURE_STRINGS)) ||
487             (!(NextInterface->Flags & ACPI_OSI_FEATURE) &&
488              (Action & ACPI_VENDOR_STRINGS)))
489         {
490             if (Action & ACPI_DISABLE_INTERFACES)
491             {
492                 /* Mark the interfaces as invalid */
493 
494                 NextInterface->Flags |= ACPI_OSI_INVALID;
495             }
496             else
497             {
498                 /* Mark the interfaces as valid */
499 
500                 NextInterface->Flags &= ~ACPI_OSI_INVALID;
501             }
502         }
503 
504         NextInterface = NextInterface->Next;
505     }
506 
507     return (AE_OK);
508 }
509 
510 
511 /*******************************************************************************
512  *
513  * FUNCTION:    AcpiUtGetInterface
514  *
515  * PARAMETERS:  InterfaceName       - The interface to find
516  *
517  * RETURN:      ACPI_INTERFACE_INFO if found. NULL if not found.
518  *
519  * DESCRIPTION: Search for the specified interface name in the global list.
520  *              Caller MUST hold AcpiGbl_OsiMutex
521  *
522  ******************************************************************************/
523 
524 ACPI_INTERFACE_INFO *
525 AcpiUtGetInterface (
526     ACPI_STRING             InterfaceName)
527 {
528     ACPI_INTERFACE_INFO     *NextInterface;
529 
530 
531     NextInterface = AcpiGbl_SupportedInterfaces;
532     while (NextInterface)
533     {
534         if (!strcmp (InterfaceName, NextInterface->Name))
535         {
536             return (NextInterface);
537         }
538 
539         NextInterface = NextInterface->Next;
540     }
541 
542     return (NULL);
543 }
544 
545 
546 /*******************************************************************************
547  *
548  * FUNCTION:    AcpiUtOsiImplementation
549  *
550  * PARAMETERS:  WalkState           - Current walk state
551  *
552  * RETURN:      Status
553  *              Integer: TRUE (0) if input string is matched
554  *                       FALSE (-1) if string is not matched
555  *
556  * DESCRIPTION: Implementation of the _OSI predefined control method. When
557  *              an invocation of _OSI is encountered in the system AML,
558  *              control is transferred to this function.
559  *
560  * (August 2016)
561  * Note:  _OSI is now defined to return "Ones" to indicate a match, for
562  * compatibility with other ACPI implementations. On a 32-bit DSDT, Ones
563  * is 0xFFFFFFFF. On a 64-bit DSDT, Ones is 0xFFFFFFFFFFFFFFFF
564  * (ACPI_UINT64_MAX).
565  *
566  * This function always returns ACPI_UINT64_MAX for TRUE, and later code
567  * will truncate this to 32 bits if necessary.
568  *
569  ******************************************************************************/
570 
571 ACPI_STATUS
572 AcpiUtOsiImplementation (
573     ACPI_WALK_STATE         *WalkState)
574 {
575     ACPI_OPERAND_OBJECT     *StringDesc;
576     ACPI_OPERAND_OBJECT     *ReturnDesc;
577     ACPI_INTERFACE_INFO     *InterfaceInfo;
578     ACPI_INTERFACE_HANDLER  InterfaceHandler;
579     ACPI_STATUS             Status;
580     UINT64                  ReturnValue;
581 
582 
583     ACPI_FUNCTION_TRACE (UtOsiImplementation);
584 
585 
586     /* Validate the string input argument (from the AML caller) */
587 
588     StringDesc = WalkState->Arguments[0].Object;
589     if (!StringDesc ||
590         (StringDesc->Common.Type != ACPI_TYPE_STRING))
591     {
592         return_ACPI_STATUS (AE_TYPE);
593     }
594 
595     /* Create a return object */
596 
597     ReturnDesc = AcpiUtCreateInternalObject (ACPI_TYPE_INTEGER);
598     if (!ReturnDesc)
599     {
600         return_ACPI_STATUS (AE_NO_MEMORY);
601     }
602 
603     /* Default return value is 0, NOT SUPPORTED */
604 
605     ReturnValue = 0;
606     Status = AcpiOsAcquireMutex (AcpiGbl_OsiMutex, ACPI_WAIT_FOREVER);
607     if (ACPI_FAILURE (Status))
608     {
609         AcpiUtRemoveReference (ReturnDesc);
610         return_ACPI_STATUS (Status);
611     }
612 
613     /* Lookup the interface in the global _OSI list */
614 
615     InterfaceInfo = AcpiUtGetInterface (StringDesc->String.Pointer);
616     if (InterfaceInfo &&
617         !(InterfaceInfo->Flags & ACPI_OSI_INVALID))
618     {
619         /*
620          * The interface is supported.
621          * Update the OsiData if necessary. We keep track of the latest
622          * version of Windows that has been requested by the BIOS.
623          */
624         if (InterfaceInfo->Value > AcpiGbl_OsiData)
625         {
626             AcpiGbl_OsiData = InterfaceInfo->Value;
627         }
628 
629         ReturnValue = ACPI_UINT64_MAX;
630     }
631 
632     AcpiOsReleaseMutex (AcpiGbl_OsiMutex);
633 
634     /*
635      * Invoke an optional _OSI interface handler. The host OS may wish
636      * to do some interface-specific handling. For example, warn about
637      * certain interfaces or override the true/false support value.
638      */
639     InterfaceHandler = AcpiGbl_InterfaceHandler;
640     if (InterfaceHandler)
641     {
642         if (InterfaceHandler (
643             StringDesc->String.Pointer, (UINT32) ReturnValue))
644         {
645             ReturnValue = ACPI_UINT64_MAX;
646         }
647     }
648 
649     ACPI_DEBUG_PRINT_RAW ((ACPI_DB_INFO,
650         "ACPI: BIOS _OSI(\"%s\") is %ssupported\n",
651         StringDesc->String.Pointer, ReturnValue == 0 ? "not " : ""));
652 
653     /* Complete the return object */
654 
655     ReturnDesc->Integer.Value = ReturnValue;
656     WalkState->ReturnDesc = ReturnDesc;
657     return_ACPI_STATUS (AE_OK);
658 }
659