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      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 - 2025, 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 
    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_1},          /* 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     {"Windows 2016",        NULL, 0, ACPI_OSI_WIN_10_RS1},       /* Windows 10 version 1607 - Added 12/2017 */
    218     {"Windows 2017",        NULL, 0, ACPI_OSI_WIN_10_RS2},       /* Windows 10 version 1703 - Added 12/2017 */
    219     {"Windows 2017.2",      NULL, 0, ACPI_OSI_WIN_10_RS3},       /* Windows 10 version 1709 - Added 02/2018 */
    220     {"Windows 2018",        NULL, 0, ACPI_OSI_WIN_10_RS4},       /* Windows 10 version 1803 - Added 11/2018 */
    221     {"Windows 2018.2",      NULL, 0, ACPI_OSI_WIN_10_RS5},       /* Windows 10 version 1809 - Added 11/2018 */
    222     {"Windows 2019",        NULL, 0, ACPI_OSI_WIN_10_19H1},      /* Windows 10 version 1903 - Added 08/2019 */
    223     {"Windows 2020",        NULL, 0, ACPI_OSI_WIN_10_20H1},      /* Windows 10 version 2004 - Added 08/2021 */
    224     {"Windows 2021",        NULL, 0, ACPI_OSI_WIN_11},           /* Windows 11 - Added 01/2022 */
    225     {"Windows 2022",        NULL, 0, ACPI_OSI_WIN_11_22H2},      /* Windows 11 version 22H2 - Added 04/2024 */
    226 
    227     /* Feature Group Strings */
    228 
    229     {"Extended Address Space Descriptor", NULL, ACPI_OSI_FEATURE, 0},
    230 
    231     /*
    232      * All "optional" feature group strings (features that are implemented
    233      * by the host) should be dynamically modified to VALID by the host via
    234      * AcpiInstallInterface or AcpiUpdateInterfaces. Such optional feature
    235      * group strings are set as INVALID by default here.
    236      */
    237 
    238     {"Module Device",               NULL, ACPI_OSI_OPTIONAL_FEATURE, 0},
    239     {"Processor Device",            NULL, ACPI_OSI_OPTIONAL_FEATURE, 0},
    240     {"3.0 Thermal Model",           NULL, ACPI_OSI_OPTIONAL_FEATURE, 0},
    241     {"3.0 _SCP Extensions",         NULL, ACPI_OSI_OPTIONAL_FEATURE, 0},
    242     {"Processor Aggregator Device", NULL, ACPI_OSI_OPTIONAL_FEATURE, 0}
    243 };
    244 
    245 
    246 /*******************************************************************************
    247  *
    248  * FUNCTION:    AcpiUtInitializeInterfaces
    249  *
    250  * PARAMETERS:  None
    251  *
    252  * RETURN:      Status
    253  *
    254  * DESCRIPTION: Initialize the global _OSI supported interfaces list
    255  *
    256  ******************************************************************************/
    257 
    258 ACPI_STATUS
    259 AcpiUtInitializeInterfaces (
    260     void)
    261 {
    262     ACPI_STATUS             Status;
    263     UINT32                  i;
    264 
    265 
    266     Status = AcpiOsAcquireMutex (AcpiGbl_OsiMutex, ACPI_WAIT_FOREVER);
    267     if (ACPI_FAILURE (Status))
    268     {
    269         return (Status);
    270     }
    271 
    272     AcpiGbl_SupportedInterfaces = AcpiDefaultSupportedInterfaces;
    273 
    274     /* Link the static list of supported interfaces */
    275 
    276     for (i = 0;
    277         i < (ACPI_ARRAY_LENGTH (AcpiDefaultSupportedInterfaces) - 1);
    278         i++)
    279     {
    280         AcpiDefaultSupportedInterfaces[i].Next =
    281             &AcpiDefaultSupportedInterfaces[(ACPI_SIZE) i + 1];
    282     }
    283 
    284     AcpiOsReleaseMutex (AcpiGbl_OsiMutex);
    285     return (AE_OK);
    286 }
    287 
    288 
    289 /*******************************************************************************
    290  *
    291  * FUNCTION:    AcpiUtInterfaceTerminate
    292  *
    293  * PARAMETERS:  None
    294  *
    295  * RETURN:      Status
    296  *
    297  * DESCRIPTION: Delete all interfaces in the global list. Sets
    298  *              AcpiGbl_SupportedInterfaces to NULL.
    299  *
    300  ******************************************************************************/
    301 
    302 ACPI_STATUS
    303 AcpiUtInterfaceTerminate (
    304     void)
    305 {
    306     ACPI_STATUS             Status;
    307     ACPI_INTERFACE_INFO     *NextInterface;
    308 
    309 
    310     Status = AcpiOsAcquireMutex (AcpiGbl_OsiMutex, ACPI_WAIT_FOREVER);
    311     if (ACPI_FAILURE (Status))
    312     {
    313         return (Status);
    314     }
    315 
    316     NextInterface = AcpiGbl_SupportedInterfaces;
    317     while (NextInterface)
    318     {
    319         AcpiGbl_SupportedInterfaces = NextInterface->Next;
    320 
    321         if (NextInterface->Flags & ACPI_OSI_DYNAMIC)
    322         {
    323             /* Only interfaces added at runtime can be freed */
    324 
    325             ACPI_FREE (__UNCONST(NextInterface->Name));
    326             ACPI_FREE (NextInterface);
    327         }
    328         else
    329         {
    330             /* Interface is in static list. Reset it to invalid or valid. */
    331 
    332             if (NextInterface->Flags & ACPI_OSI_DEFAULT_INVALID)
    333             {
    334                 NextInterface->Flags |= ACPI_OSI_INVALID;
    335             }
    336             else
    337             {
    338                 NextInterface->Flags &= ~ACPI_OSI_INVALID;
    339             }
    340         }
    341 
    342         NextInterface = AcpiGbl_SupportedInterfaces;
    343     }
    344 
    345     AcpiOsReleaseMutex (AcpiGbl_OsiMutex);
    346     return (AE_OK);
    347 }
    348 
    349 
    350 /*******************************************************************************
    351  *
    352  * FUNCTION:    AcpiUtInstallInterface
    353  *
    354  * PARAMETERS:  InterfaceName       - The interface to install
    355  *
    356  * RETURN:      Status
    357  *
    358  * DESCRIPTION: Install the interface into the global interface list.
    359  *              Caller MUST hold AcpiGbl_OsiMutex
    360  *
    361  ******************************************************************************/
    362 
    363 ACPI_STATUS
    364 AcpiUtInstallInterface (
    365     ACPI_STRING             InterfaceName)
    366 {
    367     ACPI_INTERFACE_INFO     *InterfaceInfo;
    368 
    369 
    370     /* Allocate info block and space for the name string */
    371 
    372     InterfaceInfo = ACPI_ALLOCATE_ZEROED (sizeof (ACPI_INTERFACE_INFO));
    373     if (!InterfaceInfo)
    374     {
    375         return (AE_NO_MEMORY);
    376     }
    377 
    378     InterfaceInfo->Name = ACPI_ALLOCATE_ZEROED (strlen (InterfaceName) + 1);
    379     if (!InterfaceInfo->Name)
    380     {
    381         ACPI_FREE (InterfaceInfo);
    382         return (AE_NO_MEMORY);
    383     }
    384 
    385     /* Initialize new info and insert at the head of the global list */
    386 
    387     strcpy (__UNCONST(InterfaceInfo->Name), InterfaceName);
    388     InterfaceInfo->Flags = ACPI_OSI_DYNAMIC;
    389     InterfaceInfo->Next = AcpiGbl_SupportedInterfaces;
    390 
    391     AcpiGbl_SupportedInterfaces = InterfaceInfo;
    392     return (AE_OK);
    393 }
    394 
    395 
    396 /*******************************************************************************
    397  *
    398  * FUNCTION:    AcpiUtRemoveInterface
    399  *
    400  * PARAMETERS:  InterfaceName       - The interface to remove
    401  *
    402  * RETURN:      Status
    403  *
    404  * DESCRIPTION: Remove the interface from the global interface list.
    405  *              Caller MUST hold AcpiGbl_OsiMutex
    406  *
    407  ******************************************************************************/
    408 
    409 ACPI_STATUS
    410 AcpiUtRemoveInterface (
    411     ACPI_STRING             InterfaceName)
    412 {
    413     ACPI_INTERFACE_INFO     *PreviousInterface;
    414     ACPI_INTERFACE_INFO     *NextInterface;
    415 
    416 
    417     PreviousInterface = NextInterface = AcpiGbl_SupportedInterfaces;
    418     while (NextInterface)
    419     {
    420         if (!strcmp (InterfaceName, NextInterface->Name))
    421         {
    422             /*
    423              * Found: name is in either the static list
    424              * or was added at runtime
    425              */
    426             if (NextInterface->Flags & ACPI_OSI_DYNAMIC)
    427             {
    428                 /* Interface was added dynamically, remove and free it */
    429 
    430                 if (PreviousInterface == NextInterface)
    431                 {
    432                     AcpiGbl_SupportedInterfaces = NextInterface->Next;
    433                 }
    434                 else
    435                 {
    436                     PreviousInterface->Next = NextInterface->Next;
    437                 }
    438 
    439                 ACPI_FREE (__UNCONST(NextInterface->Name));
    440                 ACPI_FREE (NextInterface);
    441             }
    442             else
    443             {
    444                 /*
    445                  * Interface is in static list. If marked invalid, then
    446                  * it does not actually exist. Else, mark it invalid.
    447                  */
    448                 if (NextInterface->Flags & ACPI_OSI_INVALID)
    449                 {
    450                     return (AE_NOT_EXIST);
    451                 }
    452 
    453                 NextInterface->Flags |= ACPI_OSI_INVALID;
    454             }
    455 
    456             return (AE_OK);
    457         }
    458 
    459         PreviousInterface = NextInterface;
    460         NextInterface = NextInterface->Next;
    461     }
    462 
    463     /* Interface was not found */
    464 
    465     return (AE_NOT_EXIST);
    466 }
    467 
    468 
    469 /*******************************************************************************
    470  *
    471  * FUNCTION:    AcpiUtUpdateInterfaces
    472  *
    473  * PARAMETERS:  Action              - Actions to be performed during the
    474  *                                    update
    475  *
    476  * RETURN:      Status
    477  *
    478  * DESCRIPTION: Update _OSI interface strings, disabling or enabling OS vendor
    479  *              strings or/and feature group strings.
    480  *              Caller MUST hold AcpiGbl_OsiMutex
    481  *
    482  ******************************************************************************/
    483 
    484 ACPI_STATUS
    485 AcpiUtUpdateInterfaces (
    486     UINT8                   Action)
    487 {
    488     ACPI_INTERFACE_INFO     *NextInterface;
    489 
    490 
    491     NextInterface = AcpiGbl_SupportedInterfaces;
    492     while (NextInterface)
    493     {
    494         if (((NextInterface->Flags & ACPI_OSI_FEATURE) &&
    495              (Action & ACPI_FEATURE_STRINGS)) ||
    496             (!(NextInterface->Flags & ACPI_OSI_FEATURE) &&
    497              (Action & ACPI_VENDOR_STRINGS)))
    498         {
    499             if (Action & ACPI_DISABLE_INTERFACES)
    500             {
    501                 /* Mark the interfaces as invalid */
    502 
    503                 NextInterface->Flags |= ACPI_OSI_INVALID;
    504             }
    505             else
    506             {
    507                 /* Mark the interfaces as valid */
    508 
    509                 NextInterface->Flags &= ~ACPI_OSI_INVALID;
    510             }
    511         }
    512 
    513         NextInterface = NextInterface->Next;
    514     }
    515 
    516     return (AE_OK);
    517 }
    518 
    519 
    520 /*******************************************************************************
    521  *
    522  * FUNCTION:    AcpiUtGetInterface
    523  *
    524  * PARAMETERS:  InterfaceName       - The interface to find
    525  *
    526  * RETURN:      ACPI_INTERFACE_INFO if found. NULL if not found.
    527  *
    528  * DESCRIPTION: Search for the specified interface name in the global list.
    529  *              Caller MUST hold AcpiGbl_OsiMutex
    530  *
    531  ******************************************************************************/
    532 
    533 ACPI_INTERFACE_INFO *
    534 AcpiUtGetInterface (
    535     ACPI_STRING             InterfaceName)
    536 {
    537     ACPI_INTERFACE_INFO     *NextInterface;
    538 
    539 
    540     NextInterface = AcpiGbl_SupportedInterfaces;
    541     while (NextInterface)
    542     {
    543         if (!strcmp (InterfaceName, NextInterface->Name))
    544         {
    545             return (NextInterface);
    546         }
    547 
    548         NextInterface = NextInterface->Next;
    549     }
    550 
    551     return (NULL);
    552 }
    553 
    554 
    555 /*******************************************************************************
    556  *
    557  * FUNCTION:    AcpiUtOsiImplementation
    558  *
    559  * PARAMETERS:  WalkState           - Current walk state
    560  *
    561  * RETURN:      Status
    562  *              Integer: TRUE (0) if input string is matched
    563  *                       FALSE (-1) if string is not matched
    564  *
    565  * DESCRIPTION: Implementation of the _OSI predefined control method. When
    566  *              an invocation of _OSI is encountered in the system AML,
    567  *              control is transferred to this function.
    568  *
    569  * (August 2016)
    570  * Note:  _OSI is now defined to return "Ones" to indicate a match, for
    571  * compatibility with other ACPI implementations. On a 32-bit DSDT, Ones
    572  * is 0xFFFFFFFF. On a 64-bit DSDT, Ones is 0xFFFFFFFFFFFFFFFF
    573  * (ACPI_UINT64_MAX).
    574  *
    575  * This function always returns ACPI_UINT64_MAX for TRUE, and later code
    576  * will truncate this to 32 bits if necessary.
    577  *
    578  ******************************************************************************/
    579 
    580 ACPI_STATUS
    581 AcpiUtOsiImplementation (
    582     ACPI_WALK_STATE         *WalkState)
    583 {
    584     ACPI_OPERAND_OBJECT     *StringDesc;
    585     ACPI_OPERAND_OBJECT     *ReturnDesc;
    586     ACPI_INTERFACE_INFO     *InterfaceInfo;
    587     ACPI_INTERFACE_HANDLER  InterfaceHandler;
    588     ACPI_STATUS             Status;
    589     UINT64                  ReturnValue;
    590 
    591 
    592     ACPI_FUNCTION_TRACE (UtOsiImplementation);
    593 
    594 
    595     /* Validate the string input argument (from the AML caller) */
    596 
    597     StringDesc = WalkState->Arguments[0].Object;
    598     if (!StringDesc ||
    599         (StringDesc->Common.Type != ACPI_TYPE_STRING))
    600     {
    601         return_ACPI_STATUS (AE_TYPE);
    602     }
    603 
    604     /* Create a return object */
    605 
    606     ReturnDesc = AcpiUtCreateInternalObject (ACPI_TYPE_INTEGER);
    607     if (!ReturnDesc)
    608     {
    609         return_ACPI_STATUS (AE_NO_MEMORY);
    610     }
    611 
    612     /* Default return value is 0, NOT SUPPORTED */
    613 
    614     ReturnValue = 0;
    615     Status = AcpiOsAcquireMutex (AcpiGbl_OsiMutex, ACPI_WAIT_FOREVER);
    616     if (ACPI_FAILURE (Status))
    617     {
    618         AcpiUtRemoveReference (ReturnDesc);
    619         return_ACPI_STATUS (Status);
    620     }
    621 
    622     /* Lookup the interface in the global _OSI list */
    623 
    624     InterfaceInfo = AcpiUtGetInterface (StringDesc->String.Pointer);
    625     if (InterfaceInfo &&
    626         !(InterfaceInfo->Flags & ACPI_OSI_INVALID))
    627     {
    628         /*
    629          * The interface is supported.
    630          * Update the OsiData if necessary. We keep track of the latest
    631          * version of Windows that has been requested by the BIOS.
    632          */
    633         if (InterfaceInfo->Value > AcpiGbl_OsiData)
    634         {
    635             AcpiGbl_OsiData = InterfaceInfo->Value;
    636         }
    637 
    638         ReturnValue = ACPI_UINT64_MAX;
    639     }
    640 
    641     AcpiOsReleaseMutex (AcpiGbl_OsiMutex);
    642 
    643     /*
    644      * Invoke an optional _OSI interface handler. The host OS may wish
    645      * to do some interface-specific handling. For example, warn about
    646      * certain interfaces or override the true/false support value.
    647      */
    648     InterfaceHandler = AcpiGbl_InterfaceHandler;
    649     if (InterfaceHandler)
    650     {
    651         if (InterfaceHandler (
    652             StringDesc->String.Pointer, (UINT32) ReturnValue))
    653         {
    654             ReturnValue = ACPI_UINT64_MAX;
    655         }
    656     }
    657 
    658     ACPI_DEBUG_PRINT_RAW ((ACPI_DB_INFO,
    659         "ACPI: BIOS _OSI(\"%s\") is %ssupported\n",
    660         StringDesc->String.Pointer, ReturnValue == 0 ? "not " : ""));
    661 
    662     /* Complete the return object */
    663 
    664     ReturnDesc->Integer.Value = ReturnValue;
    665     WalkState->ReturnDesc = ReturnDesc;
    666     return_ACPI_STATUS (AE_OK);
    667 }
    668