FreeBSD/Linux Kernel Cross Reference
sys/contrib/dev/acpica/components/utilities/utosi.c

     /******************************************************************************
      *
      * Module Name: utosi - Support for the _OSI predefined control method
      *
      *****************************************************************************/
     
     /******************************************************************************
      *
      * 1. Copyright Notice
     *
     * Some or all of this work - Copyright (c) 1999 - 2022, Intel Corp.
     * All rights reserved.
     *
     * 2. License
     *
     * 2.1. This is your license from Intel Corp. under its intellectual property
     * rights. You may have additional license terms from the party that provided
     * you this software, covering your right to use that party's intellectual
     * property rights.
     *
     * 2.2. Intel grants, free of charge, to any person ("Licensee") obtaining a
     * copy of the source code appearing in this file ("Covered Code") an
     * irrevocable, perpetual, worldwide license under Intel's copyrights in the
     * base code distributed originally by Intel ("Original Intel Code") to copy,
     * make derivatives, distribute, use and display any portion of the Covered
     * Code in any form, with the right to sublicense such rights; and
     *
     * 2.3. Intel grants Licensee a non-exclusive and non-transferable patent
     * license (with the right to sublicense), under only those claims of Intel
     * patents that are infringed by the Original Intel Code, to make, use, sell,
     * offer to sell, and import the Covered Code and derivative works thereof
     * solely to the minimum extent necessary to exercise the above copyright
     * license, and in no event shall the patent license extend to any additions
     * to or modifications of the Original Intel Code. No other license or right
     * is granted directly or by implication, estoppel or otherwise;
     *
     * The above copyright and patent license is granted only if the following
     * conditions are met:
     *
     * 3. Conditions
     *
     * 3.1. Redistribution of Source with Rights to Further Distribute Source.
     * Redistribution of source code of any substantial portion of the Covered
     * Code or modification with rights to further distribute source must include
     * the above Copyright Notice, the above License, this list of Conditions,
     * and the following Disclaimer and Export Compliance provision. In addition,
     * Licensee must cause all Covered Code to which Licensee contributes to
     * contain a file documenting the changes Licensee made to create that Covered
     * Code and the date of any change. Licensee must include in that file the
     * documentation of any changes made by any predecessor Licensee. Licensee
     * must include a prominent statement that the modification is derived,
     * directly or indirectly, from Original Intel Code.
     *
     * 3.2. Redistribution of Source with no Rights to Further Distribute Source.
     * Redistribution of source code of any substantial portion of the Covered
     * Code or modification without rights to further distribute source must
     * include the following Disclaimer and Export Compliance provision in the
     * documentation and/or other materials provided with distribution. In
     * addition, Licensee may not authorize further sublicense of source of any
     * portion of the Covered Code, and must include terms to the effect that the
     * license from Licensee to its licensee is limited to the intellectual
     * property embodied in the software Licensee provides to its licensee, and
     * not to intellectual property embodied in modifications its licensee may
     * make.
     *
     * 3.3. Redistribution of Executable. Redistribution in executable form of any
     * substantial portion of the Covered Code or modification must reproduce the
     * above Copyright Notice, and the following Disclaimer and Export Compliance
     * provision in the documentation and/or other materials provided with the
     * distribution.
     *
     * 3.4. Intel retains all right, title, and interest in and to the Original
     * Intel Code.
     *
     * 3.5. Neither the name Intel nor any other trademark owned or controlled by
     * Intel shall be used in advertising or otherwise to promote the sale, use or
     * other dealings in products derived from or relating to the Covered Code
     * without prior written authorization from Intel.
     *
     * 4. Disclaimer and Export Compliance
     *
     * 4.1. INTEL MAKES NO WARRANTY OF ANY KIND REGARDING ANY SOFTWARE PROVIDED
     * HERE. ANY SOFTWARE ORIGINATING FROM INTEL OR DERIVED FROM INTEL SOFTWARE
     * IS PROVIDED "AS IS," AND INTEL WILL NOT PROVIDE ANY SUPPORT, ASSISTANCE,
     * INSTALLATION, TRAINING OR OTHER SERVICES. INTEL WILL NOT PROVIDE ANY
     * UPDATES, ENHANCEMENTS OR EXTENSIONS. INTEL SPECIFICALLY DISCLAIMS ANY
     * IMPLIED WARRANTIES OF MERCHANTABILITY, NONINFRINGEMENT AND FITNESS FOR A
     * PARTICULAR PURPOSE.
     *
     * 4.2. IN NO EVENT SHALL INTEL HAVE ANY LIABILITY TO LICENSEE, ITS LICENSEES
     * OR ANY OTHER THIRD PARTY, FOR ANY LOST PROFITS, LOST DATA, LOSS OF USE OR
     * COSTS OF PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES, OR FOR ANY INDIRECT,
     * SPECIAL OR CONSEQUENTIAL DAMAGES ARISING OUT OF THIS AGREEMENT, UNDER ANY
     * CAUSE OF ACTION OR THEORY OF LIABILITY, AND IRRESPECTIVE OF WHETHER INTEL
     * HAS ADVANCE NOTICE OF THE POSSIBILITY OF SUCH DAMAGES. THESE LIMITATIONS
     * SHALL APPLY NOTWITHSTANDING THE FAILURE OF THE ESSENTIAL PURPOSE OF ANY
     * LIMITED REMEDY.
     *
     * 4.3. Licensee shall not export, either directly or indirectly, any of this
    * software or system incorporating such software without first obtaining any
    * required license or other approval from the U. S. Department of Commerce or
    * any other agency or department of the United States Government. In the
    * event Licensee exports any such software from the United States or
    * re-exports any such software from a foreign destination, Licensee shall
    * ensure that the distribution and export/re-export of the software is in
    * compliance with all laws, regulations, orders, or other restrictions of the
    * U.S. Export Administration Regulations. Licensee agrees that neither it nor
    * any of its subsidiaries will export/re-export any technical data, process,
    * software, or service, directly or indirectly, to any country for which the
    * United States government or any agency thereof requires an export license,
    * other governmental approval, or letter of assurance, without first obtaining
    * such license, approval or letter.
    *
    *****************************************************************************
    *
    * Alternatively, you may choose to be licensed under the terms of the
    * following license:
    *
    * Redistribution and use in source and binary forms, with or without
    * modification, are permitted provided that the following conditions
    * are met:
    * 1. Redistributions of source code must retain the above copyright
    *    notice, this list of conditions, and the following disclaimer,
    *    without modification.
    * 2. Redistributions in binary form must reproduce at minimum a disclaimer
    *    substantially similar to the "NO WARRANTY" disclaimer below
    *    ("Disclaimer") and any redistribution must be conditioned upon
    *    including a substantially similar Disclaimer requirement for further
    *    binary redistribution.
    * 3. Neither the names of the above-listed copyright holders nor the names
    *    of any contributors may be used to endorse or promote products derived
    *    from this software without specific prior written permission.
    *
    * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
    * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
    * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
    * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
    * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
    * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
    * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
    * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
    * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
    * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
    * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
    *
    * Alternatively, you may choose to be licensed under the terms of the
    * GNU General Public License ("GPL") version 2 as published by the Free
    * Software Foundation.
    *
    *****************************************************************************/
   
   #include <contrib/dev/acpica/include/acpi.h>
   #include <contrib/dev/acpica/include/accommon.h>
   
   
   #define _COMPONENT          ACPI_UTILITIES
           ACPI_MODULE_NAME    ("utosi")
   
   
   /******************************************************************************
    *
    * ACPICA policy for new _OSI strings:
    *
    * It is the stated policy of ACPICA that new _OSI strings will be integrated
    * into this module as soon as possible after they are defined. It is strongly
    * recommended that all ACPICA hosts mirror this policy and integrate any
    * changes to this module as soon as possible. There are several historical
    * reasons behind this policy:
    *
    * 1) New BIOSs tend to test only the case where the host responds TRUE to
    *    the latest version of Windows, which would respond to the latest/newest
    *    _OSI string. Not responding TRUE to the latest version of Windows will
    *    risk executing untested code paths throughout the DSDT and SSDTs.
    *
    * 2) If a new _OSI string is recognized only after a significant delay, this
    *    has the potential to cause problems on existing working machines because
    *    of the possibility that a new and different path through the ASL code
    *    will be executed.
    *
    * 3) New _OSI strings are tending to come out about once per year. A delay
    *    in recognizing a new string for a significant amount of time risks the
    *    release of another string which only compounds the initial problem.
    *
    *****************************************************************************/
   
   
   /*
    * Strings supported by the _OSI predefined control method (which is
    * implemented internally within this module.)
    *
    * March 2009: Removed "Linux" as this host no longer wants to respond true
    * for this string. Basically, the only safe OS strings are windows-related
    * and in many or most cases represent the only test path within the
    * BIOS-provided ASL code.
    *
    * The last element of each entry is used to track the newest version of
    * Windows that the BIOS has requested.
    */
   static ACPI_INTERFACE_INFO    AcpiDefaultSupportedInterfaces[] =
   {
       /* Operating System Vendor Strings */
   
       {"Windows 2000",        NULL, 0, ACPI_OSI_WIN_2000},         /* Windows 2000 */
       {"Windows 2001",        NULL, 0, ACPI_OSI_WIN_XP},           /* Windows XP */
       {"Windows 2001 SP1",    NULL, 0, ACPI_OSI_WIN_XP_SP1},       /* Windows XP SP1 */
       {"Windows 2001.1",      NULL, 0, ACPI_OSI_WINSRV_2003},      /* Windows Server 2003 */
       {"Windows 2001 SP2",    NULL, 0, ACPI_OSI_WIN_XP_SP2},       /* Windows XP SP2 */
       {"Windows 2001.1 SP1",  NULL, 0, ACPI_OSI_WINSRV_2003_SP1},  /* Windows Server 2003 SP1 - Added 03/2006 */
       {"Windows 2006",        NULL, 0, ACPI_OSI_WIN_VISTA},        /* Windows Vista - Added 03/2006 */
       {"Windows 2006.1",      NULL, 0, ACPI_OSI_WINSRV_2008},      /* Windows Server 2008 - Added 09/2009 */
       {"Windows 2006 SP1",    NULL, 0, ACPI_OSI_WIN_VISTA_SP1},    /* Windows Vista SP1 - Added 09/2009 */
       {"Windows 2006 SP2",    NULL, 0, ACPI_OSI_WIN_VISTA_SP2},    /* Windows Vista SP2 - Added 09/2010 */
       {"Windows 2009",        NULL, 0, ACPI_OSI_WIN_7},            /* Windows 7 and Server 2008 R2 - Added 09/2009 */
       {"Windows 2012",        NULL, 0, ACPI_OSI_WIN_8},            /* Windows 8 and Server 2012 - Added 08/2012 */
       {"Windows 2013",        NULL, 0, ACPI_OSI_WIN_8_1},          /* Windows 8.1 and Server 2012 R2 - Added 01/2014 */
       {"Windows 2015",        NULL, 0, ACPI_OSI_WIN_10},           /* Windows 10 - Added 03/2015 */
       {"Windows 2016",        NULL, 0, ACPI_OSI_WIN_10_RS1},       /* Windows 10 version 1607 - Added 12/2017 */
       {"Windows 2017",        NULL, 0, ACPI_OSI_WIN_10_RS2},       /* Windows 10 version 1703 - Added 12/2017 */
       {"Windows 2017.2",      NULL, 0, ACPI_OSI_WIN_10_RS3},       /* Windows 10 version 1709 - Added 02/2018 */
       {"Windows 2018",        NULL, 0, ACPI_OSI_WIN_10_RS4},       /* Windows 10 version 1803 - Added 11/2018 */
       {"Windows 2018.2",      NULL, 0, ACPI_OSI_WIN_10_RS5},       /* Windows 10 version 1809 - Added 11/2018 */
       {"Windows 2019",        NULL, 0, ACPI_OSI_WIN_10_19H1},      /* Windows 10 version 1903 - Added 08/2019 */
       {"Windows 2020",        NULL, 0, ACPI_OSI_WIN_10_20H1},      /* Windows 10 version 2004 - Added 08/2021 */
       {"Windows 2021",        NULL, 0, ACPI_OSI_WIN_11},           /* Windows 11 - Added 01/2022 */
   
       /* Feature Group Strings */
   
       {"Extended Address Space Descriptor", NULL, ACPI_OSI_FEATURE, 0},
   
       /*
        * All "optional" feature group strings (features that are implemented
        * by the host) should be dynamically modified to VALID by the host via
        * AcpiInstallInterface or AcpiUpdateInterfaces. Such optional feature
        * group strings are set as INVALID by default here.
        */
   
       {"Module Device",               NULL, ACPI_OSI_OPTIONAL_FEATURE, 0},
       {"Processor Device",            NULL, ACPI_OSI_OPTIONAL_FEATURE, 0},
       {"3.0 Thermal Model",           NULL, ACPI_OSI_OPTIONAL_FEATURE, 0},
       {"3.0 _SCP Extensions",         NULL, ACPI_OSI_OPTIONAL_FEATURE, 0},
       {"Processor Aggregator Device", NULL, ACPI_OSI_OPTIONAL_FEATURE, 0}
   };
   
   
   /*******************************************************************************
    *
    * FUNCTION:    AcpiUtInitializeInterfaces
    *
    * PARAMETERS:  None
    *
    * RETURN:      Status
    *
    * DESCRIPTION: Initialize the global _OSI supported interfaces list
    *
    ******************************************************************************/
   
   ACPI_STATUS
   AcpiUtInitializeInterfaces (
       void)
   {
       ACPI_STATUS             Status;
       UINT32                  i;
   
   
       Status = AcpiOsAcquireMutex (AcpiGbl_OsiMutex, ACPI_WAIT_FOREVER);
       if (ACPI_FAILURE (Status))
       {
           return (Status);
       }
   
       AcpiGbl_SupportedInterfaces = AcpiDefaultSupportedInterfaces;
   
       /* Link the static list of supported interfaces */
   
       for (i = 0;
           i < (ACPI_ARRAY_LENGTH (AcpiDefaultSupportedInterfaces) - 1);
           i++)
       {
           AcpiDefaultSupportedInterfaces[i].Next =
               &AcpiDefaultSupportedInterfaces[(ACPI_SIZE) i + 1];
       }
   
       AcpiOsReleaseMutex (AcpiGbl_OsiMutex);
       return (AE_OK);
   }
   
   
   /*******************************************************************************
    *
    * FUNCTION:    AcpiUtInterfaceTerminate
    *
    * PARAMETERS:  None
    *
    * RETURN:      Status
    *
    * DESCRIPTION: Delete all interfaces in the global list. Sets
    *              AcpiGbl_SupportedInterfaces to NULL.
    *
    ******************************************************************************/
   
   ACPI_STATUS
   AcpiUtInterfaceTerminate (
       void)
   {
       ACPI_STATUS             Status;
       ACPI_INTERFACE_INFO     *NextInterface;
   
   
       Status = AcpiOsAcquireMutex (AcpiGbl_OsiMutex, ACPI_WAIT_FOREVER);
       if (ACPI_FAILURE (Status))
       {
           return (Status);
       }
   
       NextInterface = AcpiGbl_SupportedInterfaces;
       while (NextInterface)
       {
           AcpiGbl_SupportedInterfaces = NextInterface->Next;
   
           if (NextInterface->Flags & ACPI_OSI_DYNAMIC)
           {
               /* Only interfaces added at runtime can be freed */
   
               ACPI_FREE (NextInterface->Name);
               ACPI_FREE (NextInterface);
           }
           else
           {
               /* Interface is in static list. Reset it to invalid or valid. */
   
               if (NextInterface->Flags & ACPI_OSI_DEFAULT_INVALID)
               {
                   NextInterface->Flags |= ACPI_OSI_INVALID;
               }
               else
               {
                   NextInterface->Flags &= ~ACPI_OSI_INVALID;
               }
           }
   
           NextInterface = AcpiGbl_SupportedInterfaces;
       }
   
       AcpiOsReleaseMutex (AcpiGbl_OsiMutex);
       return (AE_OK);
   }
   
   
   /*******************************************************************************
    *
    * FUNCTION:    AcpiUtInstallInterface
    *
    * PARAMETERS:  InterfaceName       - The interface to install
    *
    * RETURN:      Status
    *
    * DESCRIPTION: Install the interface into the global interface list.
    *              Caller MUST hold AcpiGbl_OsiMutex
    *
    ******************************************************************************/
   
   ACPI_STATUS
   AcpiUtInstallInterface (
       ACPI_STRING             InterfaceName)
   {
       ACPI_INTERFACE_INFO     *InterfaceInfo;
   
   
       /* Allocate info block and space for the name string */
   
       InterfaceInfo = ACPI_ALLOCATE_ZEROED (sizeof (ACPI_INTERFACE_INFO));
       if (!InterfaceInfo)
       {
           return (AE_NO_MEMORY);
       }
   
       InterfaceInfo->Name = ACPI_ALLOCATE_ZEROED (strlen (InterfaceName) + 1);
       if (!InterfaceInfo->Name)
       {
           ACPI_FREE (InterfaceInfo);
           return (AE_NO_MEMORY);
       }
   
       /* Initialize new info and insert at the head of the global list */
   
       strcpy (InterfaceInfo->Name, InterfaceName);
       InterfaceInfo->Flags = ACPI_OSI_DYNAMIC;
       InterfaceInfo->Next = AcpiGbl_SupportedInterfaces;
   
       AcpiGbl_SupportedInterfaces = InterfaceInfo;
       return (AE_OK);
   }
   
   
   /*******************************************************************************
    *
    * FUNCTION:    AcpiUtRemoveInterface
    *
    * PARAMETERS:  InterfaceName       - The interface to remove
    *
    * RETURN:      Status
    *
    * DESCRIPTION: Remove the interface from the global interface list.
    *              Caller MUST hold AcpiGbl_OsiMutex
    *
    ******************************************************************************/
   
   ACPI_STATUS
   AcpiUtRemoveInterface (
       ACPI_STRING             InterfaceName)
   {
       ACPI_INTERFACE_INFO     *PreviousInterface;
       ACPI_INTERFACE_INFO     *NextInterface;
   
   
       PreviousInterface = NextInterface = AcpiGbl_SupportedInterfaces;
       while (NextInterface)
       {
           if (!strcmp (InterfaceName, NextInterface->Name))
           {
               /*
                * Found: name is in either the static list
                * or was added at runtime
                */
               if (NextInterface->Flags & ACPI_OSI_DYNAMIC)
               {
                   /* Interface was added dynamically, remove and free it */
   
                   if (PreviousInterface == NextInterface)
                   {
                       AcpiGbl_SupportedInterfaces = NextInterface->Next;
                   }
                   else
                   {
                       PreviousInterface->Next = NextInterface->Next;
                   }
   
                   ACPI_FREE (NextInterface->Name);
                   ACPI_FREE (NextInterface);
               }
               else
               {
                   /*
                    * Interface is in static list. If marked invalid, then
                    * it does not actually exist. Else, mark it invalid.
                    */
                   if (NextInterface->Flags & ACPI_OSI_INVALID)
                   {
                       return (AE_NOT_EXIST);
                   }
   
                   NextInterface->Flags |= ACPI_OSI_INVALID;
               }
   
               return (AE_OK);
           }
   
           PreviousInterface = NextInterface;
           NextInterface = NextInterface->Next;
       }
   
       /* Interface was not found */
   
       return (AE_NOT_EXIST);
   }
   
   
   /*******************************************************************************
    *
    * FUNCTION:    AcpiUtUpdateInterfaces
    *
    * PARAMETERS:  Action              - Actions to be performed during the
    *                                    update
    *
    * RETURN:      Status
    *
    * DESCRIPTION: Update _OSI interface strings, disabling or enabling OS vendor
    *              strings or/and feature group strings.
    *              Caller MUST hold AcpiGbl_OsiMutex
    *
    ******************************************************************************/
   
   ACPI_STATUS
   AcpiUtUpdateInterfaces (
       UINT8                   Action)
   {
       ACPI_INTERFACE_INFO     *NextInterface;
   
   
       NextInterface = AcpiGbl_SupportedInterfaces;
       while (NextInterface)
       {
           if (((NextInterface->Flags & ACPI_OSI_FEATURE) &&
                (Action & ACPI_FEATURE_STRINGS)) ||
               (!(NextInterface->Flags & ACPI_OSI_FEATURE) &&
                (Action & ACPI_VENDOR_STRINGS)))
           {
               if (Action & ACPI_DISABLE_INTERFACES)
               {
                   /* Mark the interfaces as invalid */
   
                   NextInterface->Flags |= ACPI_OSI_INVALID;
               }
               else
               {
                   /* Mark the interfaces as valid */
   
                   NextInterface->Flags &= ~ACPI_OSI_INVALID;
               }
           }
   
           NextInterface = NextInterface->Next;
       }
   
       return (AE_OK);
   }
   
   
   /*******************************************************************************
    *
    * FUNCTION:    AcpiUtGetInterface
    *
    * PARAMETERS:  InterfaceName       - The interface to find
    *
    * RETURN:      ACPI_INTERFACE_INFO if found. NULL if not found.
    *
    * DESCRIPTION: Search for the specified interface name in the global list.
    *              Caller MUST hold AcpiGbl_OsiMutex
    *
    ******************************************************************************/
   
   ACPI_INTERFACE_INFO *
   AcpiUtGetInterface (
       ACPI_STRING             InterfaceName)
   {
       ACPI_INTERFACE_INFO     *NextInterface;
   
   
       NextInterface = AcpiGbl_SupportedInterfaces;
       while (NextInterface)
       {
           if (!strcmp (InterfaceName, NextInterface->Name))
           {
               return (NextInterface);
           }
   
           NextInterface = NextInterface->Next;
       }
   
       return (NULL);
   }
   
   
   /*******************************************************************************
    *
    * FUNCTION:    AcpiUtOsiImplementation
    *
    * PARAMETERS:  WalkState           - Current walk state
    *
    * RETURN:      Status
    *              Integer: TRUE (0) if input string is matched
    *                       FALSE (-1) if string is not matched
    *
    * DESCRIPTION: Implementation of the _OSI predefined control method. When
    *              an invocation of _OSI is encountered in the system AML,
    *              control is transferred to this function.
    *
    * (August 2016)
    * Note:  _OSI is now defined to return "Ones" to indicate a match, for
    * compatibility with other ACPI implementations. On a 32-bit DSDT, Ones
    * is 0xFFFFFFFF. On a 64-bit DSDT, Ones is 0xFFFFFFFFFFFFFFFF
    * (ACPI_UINT64_MAX).
    *
    * This function always returns ACPI_UINT64_MAX for TRUE, and later code
    * will truncate this to 32 bits if necessary.
    *
    ******************************************************************************/
   
   ACPI_STATUS
   AcpiUtOsiImplementation (
       ACPI_WALK_STATE         *WalkState)
   {
       ACPI_OPERAND_OBJECT     *StringDesc;
       ACPI_OPERAND_OBJECT     *ReturnDesc;
       ACPI_INTERFACE_INFO     *InterfaceInfo;
       ACPI_INTERFACE_HANDLER  InterfaceHandler;
       ACPI_STATUS             Status;
       UINT64                  ReturnValue;
   
   
       ACPI_FUNCTION_TRACE (UtOsiImplementation);
   
   
       /* Validate the string input argument (from the AML caller) */
   
       StringDesc = WalkState->Arguments[0].Object;
       if (!StringDesc ||
           (StringDesc->Common.Type != ACPI_TYPE_STRING))
       {
           return_ACPI_STATUS (AE_TYPE);
       }
   
       /* Create a return object */
   
       ReturnDesc = AcpiUtCreateInternalObject (ACPI_TYPE_INTEGER);
       if (!ReturnDesc)
       {
           return_ACPI_STATUS (AE_NO_MEMORY);
       }
   
       /* Default return value is 0, NOT SUPPORTED */
   
       ReturnValue = 0;
       Status = AcpiOsAcquireMutex (AcpiGbl_OsiMutex, ACPI_WAIT_FOREVER);
       if (ACPI_FAILURE (Status))
       {
           AcpiUtRemoveReference (ReturnDesc);
           return_ACPI_STATUS (Status);
       }
   
       /* Lookup the interface in the global _OSI list */
   
       InterfaceInfo = AcpiUtGetInterface (StringDesc->String.Pointer);
       if (InterfaceInfo &&
           !(InterfaceInfo->Flags & ACPI_OSI_INVALID))
       {
           /*
            * The interface is supported.
            * Update the OsiData if necessary. We keep track of the latest
            * version of Windows that has been requested by the BIOS.
            */
           if (InterfaceInfo->Value > AcpiGbl_OsiData)
           {
               AcpiGbl_OsiData = InterfaceInfo->Value;
           }
   
           ReturnValue = ACPI_UINT64_MAX;
       }
   
       AcpiOsReleaseMutex (AcpiGbl_OsiMutex);
   
       /*
        * Invoke an optional _OSI interface handler. The host OS may wish
        * to do some interface-specific handling. For example, warn about
        * certain interfaces or override the true/false support value.
        */
       InterfaceHandler = AcpiGbl_InterfaceHandler;
       if (InterfaceHandler)
       {
           if (InterfaceHandler (
               StringDesc->String.Pointer, (UINT32) ReturnValue))
           {
               ReturnValue = ACPI_UINT64_MAX;
           }
       }
   
       ACPI_DEBUG_PRINT_RAW ((ACPI_DB_INFO,
           "ACPI: BIOS _OSI(\"%s\") is %ssupported\n",
           StringDesc->String.Pointer, ReturnValue == 0 ? "not " : ""));
   
       /* Complete the return object */
   
       ReturnDesc->Integer.Value = ReturnValue;
       WalkState->ReturnDesc = ReturnDesc;
       return_ACPI_STATUS (AE_OK);
   }

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