dsutils.c

acpi tools for linux include acpiexec and acpixtract

/*******************************************************************************
 *
 * Module Name: dsutils - Dispatcher utilities
 *              $Revision: 1.127 $
 *
 ******************************************************************************/

/******************************************************************************
 *
 * 1. Copyright Notice
 *
 * Some or all of this work - Copyright (c) 1999 - 2008, 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.
 *
 *****************************************************************************/

#define __DSUTILS_C__

#include "acpi.h"
#include "acparser.h"
#include "amlcode.h"
#include "acdispat.h"
#include "acinterp.h"
#include "acnamesp.h"
#include "acdebug.h"

#define _COMPONENT          ACPI_DISPATCHER
        ACPI_MODULE_NAME    ("dsutils")


/*******************************************************************************
 *
 * FUNCTION:    AcpiDsClearImplicitReturn
 *
 * PARAMETERS:  WalkState           - Current State
 *
 * RETURN:      None.
 *
 * DESCRIPTION: Clear and remove a reference on an implicit return value.  Used
 *              to delete "stale" return values (if enabled, the return value
 *              from every operator is saved at least momentarily, in case the
 *              parent method exits.)
 *
 ******************************************************************************/

void
AcpiDsClearImplicitReturn (
    ACPI_WALK_STATE         *WalkState)
{
    ACPI_FUNCTION_NAME (DsClearImplicitReturn);


    /*
     * Slack must be enabled for this feature
     */
    if (!AcpiGbl_EnableInterpreterSlack)
    {
        return;
    }

    if (WalkState->ImplicitReturnObj)
    {
        /*
         * Delete any "stale" implicit return. However, in
         * complex statements, the implicit return value can be
         * bubbled up several levels.
         */
        ACPI_DEBUG_PRINT ((ACPI_DB_DISPATCH,
            "Removing reference on stale implicit return obj %p\n",
            WalkState->ImplicitReturnObj));

        AcpiUtRemoveReference (WalkState->ImplicitReturnObj);
        WalkState->ImplicitReturnObj = NULL;
    }
}


#ifndef ACPI_NO_METHOD_EXECUTION
/*******************************************************************************
 *
 * FUNCTION:    AcpiDsDoImplicitReturn
 *
 * PARAMETERS:  ReturnDesc          - The return value
 *              WalkState           - Current State
 *              AddReference        - True if a reference should be added to the
 *                                    return object
 *
 * RETURN:      TRUE if implicit return enabled, FALSE otherwise
 *
 * DESCRIPTION: Implements the optional "implicit return".  We save the result
 *              of every ASL operator and control method invocation in case the
 *              parent method exit.  Before storing a new return value, we
 *              delete the previous return value.
 *
 ******************************************************************************/

BOOLEAN
AcpiDsDoImplicitReturn (
    ACPI_OPERAND_OBJECT     *ReturnDesc,
    ACPI_WALK_STATE         *WalkState,
    BOOLEAN                 AddReference)
{
    ACPI_FUNCTION_NAME (DsDoImplicitReturn);


    /*
     * Slack must be enabled for this feature, and we must
     * have a valid return object
     */
    if ((!AcpiGbl_EnableInterpreterSlack) ||
        (!ReturnDesc))
    {
        return (FALSE);
    }

    ACPI_DEBUG_PRINT ((ACPI_DB_DISPATCH,
            "Result %p will be implicitly returned; Prev=%p\n",
            ReturnDesc,
            WalkState->ImplicitReturnObj));

    /*
     * Delete any "stale" implicit return value first. However, in
     * complex statements, the implicit return value can be
     * bubbled up several levels, so we don't clear the value if it
     * is the same as the ReturnDesc.
     */
    if (WalkState->ImplicitReturnObj)
    {
        if (WalkState->ImplicitReturnObj == ReturnDesc)
        {
            return (TRUE);
        }
        AcpiDsClearImplicitReturn (WalkState);
    }

    /* Save the implicit return value, add a reference if requested */

    WalkState->ImplicitReturnObj = ReturnDesc;
    if (AddReference)
    {
        AcpiUtAddReference (ReturnDesc);
    }

    return (TRUE);
}


/*******************************************************************************
 *
 * FUNCTION:    AcpiDsIsResultUsed
 *
 * PARAMETERS:  Op                  - Current Op
 *              WalkState           - Current State
 *
 * RETURN:      TRUE if result is used, FALSE otherwise
 *
 * DESCRIPTION: Check if a result object will be used by the parent
 *
 ******************************************************************************/

BOOLEAN
AcpiDsIsResultUsed (
    ACPI_PARSE_OBJECT       *Op,
    ACPI_WALK_STATE         *WalkState)
{
    const ACPI_OPCODE_INFO  *ParentInfo;

    ACPI_FUNCTION_TRACE_PTR (DsIsResultUsed, Op);


    /* Must have both an Op and a Result Object */

    if (!Op)
    {
        ACPI_ERROR ((AE_INFO, "Null Op"));
        return_UINT8 (TRUE);
    }

    /*
     * We know that this operator is not a
     * Return() operator (would not come here.) The following code is the
     * optional support for a so-called "implicit return". Some AML code
     * assumes that the last value of the method is "implicitly" returned
     * to the caller. Just save the last result as the return value.
     * NOTE: this is optional because the ASL language does not actually
     * support this behavior.
     */
    (void) AcpiDsDoImplicitReturn (WalkState->ResultObj, WalkState, TRUE);

    /*
     * Now determine if the parent will use the result
     *
     * If there is no parent, or the parent is a ScopeOp, we are executing
     * at the method level. An executing method typically has no parent,
     * since each method is parsed separately.  A method invoked externally
     * via ExecuteControlMethod has a ScopeOp as the parent.
     */
    if ((!Op->Common.Parent) ||
        (Op->Common.Parent->Common.AmlOpcode == AML_SCOPE_OP))
    {
        /* No parent, the return value cannot possibly be used */

        ACPI_DEBUG_PRINT ((ACPI_DB_DISPATCH,
            "At Method level, result of [%s] not used\n",
            AcpiPsGetOpcodeName (Op->Common.AmlOpcode)));
        return_UINT8 (FALSE);
    }

    /* Get info on the parent. The RootOp is AML_SCOPE */

    ParentInfo = AcpiPsGetOpcodeInfo (Op->Common.Parent->Common.AmlOpcode);
    if (ParentInfo->Class == AML_CLASS_UNKNOWN)
    {
        ACPI_ERROR ((AE_INFO,
            "Unknown parent opcode Op=%p", Op));
        return_UINT8 (FALSE);
    }

    /*
     * Decide what to do with the result based on the parent.  If
     * the parent opcode will not use the result, delete the object.
     * Otherwise leave it as is, it will be deleted when it is used
     * as an operand later.
     */
    switch (ParentInfo->Class)
    {
    case AML_CLASS_CONTROL:

        switch (Op->Common.Parent->Common.AmlOpcode)
        {
        case AML_RETURN_OP:

            /* Never delete the return value associated with a return opcode */

            goto ResultUsed;

        case AML_IF_OP: