/******************************************************************************* * * Module Name: utresrc - Resource management utilities * ******************************************************************************/ /****************************************************************************** * * 1. Copyright Notice * * Some or all of this work - Copyright (c) 1999 - 2021, 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 "acpi.h" #include "accommon.h" #include "acresrc.h" #define _COMPONENT ACPI_UTILITIES ACPI_MODULE_NAME ("utresrc") /* * Base sizes of the raw AML resource descriptors, indexed by resource type. * Zero indicates a reserved (and therefore invalid) resource type. */ const UINT8 AcpiGbl_ResourceAmlSizes[] = { /* Small descriptors */ 0, 0, 0, 0, ACPI_AML_SIZE_SMALL (AML_RESOURCE_IRQ), ACPI_AML_SIZE_SMALL (AML_RESOURCE_DMA), ACPI_AML_SIZE_SMALL (AML_RESOURCE_START_DEPENDENT), ACPI_AML_SIZE_SMALL (AML_RESOURCE_END_DEPENDENT), ACPI_AML_SIZE_SMALL (AML_RESOURCE_IO), ACPI_AML_SIZE_SMALL (AML_RESOURCE_FIXED_IO), ACPI_AML_SIZE_SMALL (AML_RESOURCE_FIXED_DMA), 0, 0, 0, ACPI_AML_SIZE_SMALL (AML_RESOURCE_VENDOR_SMALL), ACPI_AML_SIZE_SMALL (AML_RESOURCE_END_TAG), /* Large descriptors */ 0, ACPI_AML_SIZE_LARGE (AML_RESOURCE_MEMORY24), ACPI_AML_SIZE_LARGE (AML_RESOURCE_GENERIC_REGISTER), 0, ACPI_AML_SIZE_LARGE (AML_RESOURCE_VENDOR_LARGE), ACPI_AML_SIZE_LARGE (AML_RESOURCE_MEMORY32), ACPI_AML_SIZE_LARGE (AML_RESOURCE_FIXED_MEMORY32), ACPI_AML_SIZE_LARGE (AML_RESOURCE_ADDRESS32), ACPI_AML_SIZE_LARGE (AML_RESOURCE_ADDRESS16), ACPI_AML_SIZE_LARGE (AML_RESOURCE_EXTENDED_IRQ), ACPI_AML_SIZE_LARGE (AML_RESOURCE_ADDRESS64), ACPI_AML_SIZE_LARGE (AML_RESOURCE_EXTENDED_ADDRESS64), ACPI_AML_SIZE_LARGE (AML_RESOURCE_GPIO), ACPI_AML_SIZE_LARGE (AML_RESOURCE_PIN_FUNCTION), ACPI_AML_SIZE_LARGE (AML_RESOURCE_COMMON_SERIALBUS), ACPI_AML_SIZE_LARGE (AML_RESOURCE_PIN_CONFIG), ACPI_AML_SIZE_LARGE (AML_RESOURCE_PIN_GROUP), ACPI_AML_SIZE_LARGE (AML_RESOURCE_PIN_GROUP_FUNCTION), ACPI_AML_SIZE_LARGE (AML_RESOURCE_PIN_GROUP_CONFIG), }; const UINT8 AcpiGbl_ResourceAmlSerialBusSizes[] = { 0, ACPI_AML_SIZE_LARGE (AML_RESOURCE_I2C_SERIALBUS), ACPI_AML_SIZE_LARGE (AML_RESOURCE_SPI_SERIALBUS), ACPI_AML_SIZE_LARGE (AML_RESOURCE_UART_SERIALBUS), ACPI_AML_SIZE_LARGE (AML_RESOURCE_CSI2_SERIALBUS), }; /* * Resource types, used to validate the resource length field. * The length of fixed-length types must match exactly, variable * lengths must meet the minimum required length, etc. * Zero indicates a reserved (and therefore invalid) resource type. */ static const UINT8 AcpiGbl_ResourceTypes[] = { /* Small descriptors */ 0, 0, 0, 0, ACPI_SMALL_VARIABLE_LENGTH, /* 04 IRQ */ ACPI_FIXED_LENGTH, /* 05 DMA */ ACPI_SMALL_VARIABLE_LENGTH, /* 06 StartDependentFunctions */ ACPI_FIXED_LENGTH, /* 07 EndDependentFunctions */ ACPI_FIXED_LENGTH, /* 08 IO */ ACPI_FIXED_LENGTH, /* 09 FixedIO */ ACPI_FIXED_LENGTH, /* 0A FixedDMA */ 0, 0, 0, ACPI_VARIABLE_LENGTH, /* 0E VendorShort */ ACPI_FIXED_LENGTH, /* 0F EndTag */ /* Large descriptors */ 0, ACPI_FIXED_LENGTH, /* 01 Memory24 */ ACPI_FIXED_LENGTH, /* 02 GenericRegister */ 0, ACPI_VARIABLE_LENGTH, /* 04 VendorLong */ ACPI_FIXED_LENGTH, /* 05 Memory32 */ ACPI_FIXED_LENGTH, /* 06 Memory32Fixed */ ACPI_VARIABLE_LENGTH, /* 07 Dword* address */ ACPI_VARIABLE_LENGTH, /* 08 Word* address */ ACPI_VARIABLE_LENGTH, /* 09 ExtendedIRQ */ ACPI_VARIABLE_LENGTH, /* 0A Qword* address */ ACPI_FIXED_LENGTH, /* 0B Extended* address */ ACPI_VARIABLE_LENGTH, /* 0C Gpio* */ ACPI_VARIABLE_LENGTH, /* 0D PinFunction */ ACPI_VARIABLE_LENGTH, /* 0E *SerialBus */ ACPI_VARIABLE_LENGTH, /* 0F PinConfig */ ACPI_VARIABLE_LENGTH, /* 10 PinGroup */ ACPI_VARIABLE_LENGTH, /* 11 PinGroupFunction */ ACPI_VARIABLE_LENGTH, /* 12 PinGroupConfig */ }; /******************************************************************************* * * FUNCTION: AcpiUtWalkAmlResources * * PARAMETERS: WalkState - Current walk info * PARAMETERS: Aml - Pointer to the raw AML resource template * AmlLength - Length of the entire template * UserFunction - Called once for each descriptor found. If * NULL, a pointer to the EndTag is returned * Context - Passed to UserFunction * * RETURN: Status * * DESCRIPTION: Walk a raw AML resource list(buffer). User function called * once for each resource found. * ******************************************************************************/ ACPI_STATUS AcpiUtWalkAmlResources ( ACPI_WALK_STATE *WalkState, UINT8 *Aml, ACPI_SIZE AmlLength, ACPI_WALK_AML_CALLBACK UserFunction, void **Context) { ACPI_STATUS Status; UINT8 *EndAml; UINT8 ResourceIndex; UINT32 Length; UINT32 Offset = 0; UINT8 EndTag[2] = {0x79, 0x00}; ACPI_FUNCTION_TRACE (UtWalkAmlResources); /* The absolute minimum resource template is one EndTag descriptor */ if (AmlLength < sizeof (AML_RESOURCE_END_TAG)) { return_ACPI_STATUS (AE_AML_NO_RESOURCE_END_TAG); } /* Point to the end of the resource template buffer */ EndAml = Aml + AmlLength; /* Walk the byte list, abort on any invalid descriptor type or length */ while (Aml < EndAml) { /* Validate the Resource Type and Resource Length */ Status = AcpiUtValidateResource (WalkState, Aml, &ResourceIndex); if (ACPI_FAILURE (Status)) { /* * Exit on failure. Cannot continue because the descriptor * length may be bogus also. */ return_ACPI_STATUS (Status); } /* Get the length of this descriptor */ Length = AcpiUtGetDescriptorLength (Aml); /* Invoke the user function */ if (UserFunction) { Status = UserFunction ( Aml, Length, Offset, ResourceIndex, Context); if (ACPI_FAILURE (Status)) { return_ACPI_STATUS (Status); } } /* An EndTag descriptor terminates this resource template */ if (AcpiUtGetResourceType (Aml) == ACPI_RESOURCE_NAME_END_TAG) { /* * There must be at least one more byte in the buffer for * the 2nd byte of the EndTag */ if ((Aml + 1) >= EndAml) { return_ACPI_STATUS (AE_AML_NO_RESOURCE_END_TAG); } /* * Don't attempt to perform any validation on the 2nd byte. * Although all known ASL compilers insert a zero for the 2nd * byte, it can also be a checksum (as per the ACPI spec), * and this is occasionally seen in the field. July 2017. */ /* Return the pointer to the EndTag if requested */ if (!UserFunction) { *Context = Aml; } /* Normal exit */ return_ACPI_STATUS (AE_OK); } Aml += Length; Offset += Length; } /* Did not find an EndTag descriptor */ if (UserFunction) { /* Insert an EndTag anyway. AcpiRsGetListLength always leaves room */ (void) AcpiUtValidateResource (WalkState, EndTag, &ResourceIndex); Status = UserFunction (EndTag, 2, Offset, ResourceIndex, Context); if (ACPI_FAILURE (Status)) { return_ACPI_STATUS (Status); } } return_ACPI_STATUS (AE_AML_NO_RESOURCE_END_TAG); } /******************************************************************************* * * FUNCTION: AcpiUtValidateResource * * PARAMETERS: WalkState - Current walk info * Aml - Pointer to the raw AML resource descriptor * ReturnIndex - Where the resource index is returned. NULL * if the index is not required. * * RETURN: Status, and optionally the Index into the global resource tables * * DESCRIPTION: Validate an AML resource descriptor by checking the Resource * Type and Resource Length. Returns an index into the global * resource information/dispatch tables for later use. * ******************************************************************************/ ACPI_STATUS AcpiUtValidateResource ( ACPI_WALK_STATE *WalkState, void *Aml, UINT8 *ReturnIndex) { AML_RESOURCE *AmlResource; UINT8 ResourceType; UINT8 ResourceIndex; ACPI_RS_LENGTH ResourceLength; ACPI_RS_LENGTH MinimumResourceLength; ACPI_FUNCTION_ENTRY (); /* * 1) Validate the ResourceType field (Byte 0) */ ResourceType = ACPI_GET8 (Aml); if (ReturnIndex) { *ReturnIndex = 0; /* silence bogus gcc warning */ } /* * Byte 0 contains the descriptor name (Resource Type) * Examine the large/small bit in the resource header */ if (ResourceType & ACPI_RESOURCE_NAME_LARGE) { /* Verify the large resource type (name) against the max */ if (ResourceType > ACPI_RESOURCE_NAME_LARGE_MAX) { goto InvalidResource; } /* * Large Resource Type -- bits 6:0 contain the name * Translate range 0x80-0x8B to index range 0x10-0x1B */ ResourceIndex = (UINT8) (ResourceType - 0x70); } else { /* * Small Resource Type -- bits 6:3 contain the name * Shift range to index range 0x00-0x0F */ ResourceIndex = (UINT8) ((ResourceType & ACPI_RESOURCE_NAME_SMALL_MASK) >> 3); } /* * Check validity of the resource type, via AcpiGbl_ResourceTypes. * Zero indicates an invalid resource. */ if (!AcpiGbl_ResourceTypes[ResourceIndex]) { goto InvalidResource; } /* * Validate the ResourceLength field. This ensures that the length * is at least reasonable, and guarantees that it is non-zero. */ ResourceLength = AcpiUtGetResourceLength (Aml); MinimumResourceLength = AcpiGbl_ResourceAmlSizes[ResourceIndex]; /* Validate based upon the type of resource - fixed length or variable */ switch (AcpiGbl_ResourceTypes[ResourceIndex]) { case ACPI_FIXED_LENGTH: /* Fixed length resource, length must match exactly */ if (ResourceLength != MinimumResourceLength) { goto BadResourceLength; } break; case ACPI_VARIABLE_LENGTH: /* Variable length resource, length must be at least the minimum */ if (ResourceLength < MinimumResourceLength) { goto BadResourceLength; } break; case ACPI_SMALL_VARIABLE_LENGTH: /* Small variable length resource, length can be (Min) or (Min-1) */ if ((ResourceLength > MinimumResourceLength) || (ResourceLength < (MinimumResourceLength - 1))) { goto BadResourceLength; } break; default: /* Shouldn't happen (because of validation earlier), but be sure */ goto InvalidResource; } AmlResource = ACPI_CAST_PTR (AML_RESOURCE, Aml); if (ResourceType == ACPI_RESOURCE_NAME_SERIAL_BUS) { /* Validate the BusType field */ if ((AmlResource->CommonSerialBus.Type == 0) || (AmlResource->CommonSerialBus.Type > AML_RESOURCE_MAX_SERIALBUSTYPE)) { if (WalkState) { ACPI_ERROR ((AE_INFO, "Invalid/unsupported SerialBus resource descriptor: BusType 0x%2.2X", AmlResource->CommonSerialBus.Type)); } return (AE_AML_INVALID_RESOURCE_TYPE); } } /* Optionally return the resource table index */ if (ReturnIndex) { *ReturnIndex = ResourceIndex; } return (AE_OK); InvalidResource: if (WalkState) { ACPI_ERROR ((AE_INFO, "Invalid/unsupported resource descriptor: Type 0x%2.2X", ResourceType)); } return (AE_AML_INVALID_RESOURCE_TYPE); BadResourceLength: if (WalkState) { ACPI_ERROR ((AE_INFO, "Invalid resource descriptor length: Type " "0x%2.2X, Length 0x%4.4X, MinLength 0x%4.4X", ResourceType, ResourceLength, MinimumResourceLength)); } return (AE_AML_BAD_RESOURCE_LENGTH); } /******************************************************************************* * * FUNCTION: AcpiUtGetResourceType * * PARAMETERS: Aml - Pointer to the raw AML resource descriptor * * RETURN: The Resource Type with no extraneous bits (except the * Large/Small descriptor bit -- this is left alone) * * DESCRIPTION: Extract the Resource Type/Name from the first byte of * a resource descriptor. * ******************************************************************************/ UINT8 AcpiUtGetResourceType ( void *Aml) { ACPI_FUNCTION_ENTRY (); /* * Byte 0 contains the descriptor name (Resource Type) * Examine the large/small bit in the resource header */ if (ACPI_GET8 (Aml) & ACPI_RESOURCE_NAME_LARGE) { /* Large Resource Type -- bits 6:0 contain the name */ return (ACPI_GET8 (Aml)); } else { /* Small Resource Type -- bits 6:3 contain the name */ return ((UINT8) (ACPI_GET8 (Aml) & ACPI_RESOURCE_NAME_SMALL_MASK)); } } /******************************************************************************* * * FUNCTION: AcpiUtGetResourceLength * * PARAMETERS: Aml - Pointer to the raw AML resource descriptor * * RETURN: Byte Length * * DESCRIPTION: Get the "Resource Length" of a raw AML descriptor. By * definition, this does not include the size of the descriptor * header or the length field itself. * ******************************************************************************/ UINT16 AcpiUtGetResourceLength ( void *Aml) { ACPI_RS_LENGTH ResourceLength; ACPI_FUNCTION_ENTRY (); /* * Byte 0 contains the descriptor name (Resource Type) * Examine the large/small bit in the resource header */ if (ACPI_GET8 (Aml) & ACPI_RESOURCE_NAME_LARGE) { /* Large Resource type -- bytes 1-2 contain the 16-bit length */ ACPI_MOVE_16_TO_16 (&ResourceLength, ACPI_ADD_PTR (UINT8, Aml, 1)); } else { /* Small Resource type -- bits 2:0 of byte 0 contain the length */ ResourceLength = (UINT16) (ACPI_GET8 (Aml) & ACPI_RESOURCE_NAME_SMALL_LENGTH_MASK); } return (ResourceLength); } /******************************************************************************* * * FUNCTION: AcpiUtGetResourceHeaderLength * * PARAMETERS: Aml - Pointer to the raw AML resource descriptor * * RETURN: Length of the AML header (depends on large/small descriptor) * * DESCRIPTION: Get the length of the header for this resource. * ******************************************************************************/ UINT8 AcpiUtGetResourceHeaderLength ( void *Aml) { ACPI_FUNCTION_ENTRY (); /* Examine the large/small bit in the resource header */ if (ACPI_GET8 (Aml) & ACPI_RESOURCE_NAME_LARGE) { return (sizeof (AML_RESOURCE_LARGE_HEADER)); } else { return (sizeof (AML_RESOURCE_SMALL_HEADER)); } } /******************************************************************************* * * FUNCTION: AcpiUtGetDescriptorLength * * PARAMETERS: Aml - Pointer to the raw AML resource descriptor * * RETURN: Byte length * * DESCRIPTION: Get the total byte length of a raw AML descriptor, including the * length of the descriptor header and the length field itself. * Used to walk descriptor lists. * ******************************************************************************/ UINT32 AcpiUtGetDescriptorLength ( void *Aml) { ACPI_FUNCTION_ENTRY (); /* * Get the Resource Length (does not include header length) and add * the header length (depends on if this is a small or large resource) */ return (AcpiUtGetResourceLength (Aml) + AcpiUtGetResourceHeaderLength (Aml)); } /******************************************************************************* * * FUNCTION: AcpiUtGetResourceEndTag * * PARAMETERS: ObjDesc - The resource template buffer object * EndTag - Where the pointer to the EndTag is returned * * RETURN: Status, pointer to the end tag * * DESCRIPTION: Find the EndTag resource descriptor in an AML resource template * Note: allows a buffer length of zero. * ******************************************************************************/ ACPI_STATUS AcpiUtGetResourceEndTag ( ACPI_OPERAND_OBJECT *ObjDesc, UINT8 **EndTag) { ACPI_STATUS Status; ACPI_FUNCTION_TRACE (UtGetResourceEndTag); /* Allow a buffer length of zero */ if (!ObjDesc->Buffer.Length) { *EndTag = ObjDesc->Buffer.Pointer; return_ACPI_STATUS (AE_OK); } /* Validate the template and get a pointer to the EndTag */ Status = AcpiUtWalkAmlResources (NULL, ObjDesc->Buffer.Pointer, ObjDesc->Buffer.Length, NULL, (void **) EndTag); return_ACPI_STATUS (Status); }