dsmethod.c

acpi tools for linux include acpiexec and acpixtract

        if (ACPI_FAILURE (Status))
        {
            goto Cleanup;
        }
    }

    /*
     * Increment the method parse tree thread count since it has been
     * reentered one more time (even if it is the same thread)
     */
    ObjDesc->Method.ThreadCount++;
    AcpiMethodCount++;
    return_ACPI_STATUS (Status);


Cleanup:
    /* On error, must release the method mutex (if present) */

    if (ObjDesc->Method.Mutex)
    {
        AcpiOsReleaseMutex (ObjDesc->Method.Mutex->Mutex.OsMutex);
    }
    return_ACPI_STATUS (Status);
}


/*******************************************************************************
 *
 * FUNCTION:    AcpiDsCallControlMethod
 *
 * PARAMETERS:  Thread              - Info for this thread
 *              ThisWalkState       - Current walk state
 *              Op                  - Current Op to be walked
 *
 * RETURN:      Status
 *
 * DESCRIPTION: Transfer execution to a called control method
 *
 ******************************************************************************/

ACPI_STATUS
AcpiDsCallControlMethod (
    ACPI_THREAD_STATE       *Thread,
    ACPI_WALK_STATE         *ThisWalkState,
    ACPI_PARSE_OBJECT       *Op)
{
    ACPI_STATUS             Status;
    ACPI_NAMESPACE_NODE     *MethodNode;
    ACPI_WALK_STATE         *NextWalkState = NULL;
    ACPI_OPERAND_OBJECT     *ObjDesc;
    ACPI_EVALUATE_INFO      *Info;
    UINT32                  i;


    ACPI_FUNCTION_TRACE_PTR (DsCallControlMethod, ThisWalkState);

    ACPI_DEBUG_PRINT ((ACPI_DB_DISPATCH, "Calling method %p, currentstate=%p\n",
        ThisWalkState->PrevOp, ThisWalkState));

    /*
     * Get the namespace entry for the control method we are about to call
     */
    MethodNode = ThisWalkState->MethodCallNode;
    if (!MethodNode)
    {
        return_ACPI_STATUS (AE_NULL_ENTRY);
    }

    ObjDesc = AcpiNsGetAttachedObject (MethodNode);
    if (!ObjDesc)
    {
        return_ACPI_STATUS (AE_NULL_OBJECT);
    }

    /* Init for new method, possibly wait on method mutex */

    Status = AcpiDsBeginMethodExecution (MethodNode, ObjDesc,
                ThisWalkState);
    if (ACPI_FAILURE (Status))
    {
        return_ACPI_STATUS (Status);
    }

    /* Begin method parse/execution. Create a new walk state */

    NextWalkState = AcpiDsCreateWalkState (ObjDesc->Method.OwnerId,
                        NULL, ObjDesc, Thread);
    if (!NextWalkState)
    {
        Status = AE_NO_MEMORY;
        goto Cleanup;
    }

    /*
     * The resolved arguments were put on the previous walk state's operand
     * stack. Operands on the previous walk state stack always
     * start at index 0. Also, null terminate the list of arguments
     */
    ThisWalkState->Operands [ThisWalkState->NumOperands] = NULL;

    /*
     * Allocate and initialize the evaluation information block
     * TBD: this is somewhat inefficient, should change interface to
     * DsInitAmlWalk. For now, keeps this struct off the CPU stack
     */
    Info = ACPI_ALLOCATE_ZEROED (sizeof (ACPI_EVALUATE_INFO));
    if (!Info)
    {
        return_ACPI_STATUS (AE_NO_MEMORY);
    }

    Info->Parameters = &ThisWalkState->Operands[0];
    Info->ParameterType = ACPI_PARAM_ARGS;

    Status = AcpiDsInitAmlWalk (NextWalkState, NULL, MethodNode,
                ObjDesc->Method.AmlStart, ObjDesc->Method.AmlLength,
                Info, ACPI_IMODE_EXECUTE);

    ACPI_FREE (Info);
    if (ACPI_FAILURE (Status))
    {
        goto Cleanup;
    }

    /*
     * Delete the operands on the previous walkstate operand stack
     * (they were copied to new objects)
     */
    for (i = 0; i < ObjDesc->Method.ParamCount; i++)
    {
        AcpiUtRemoveReference (ThisWalkState->Operands [i]);
        ThisWalkState->Operands [i] = NULL;
    }

    /* Clear the operand stack */

    ThisWalkState->NumOperands = 0;

    ACPI_DEBUG_PRINT ((ACPI_DB_DISPATCH,
        "**** Begin nested execution of [%4.4s] **** WalkState=%p\n",
        MethodNode->Name.Ascii, NextWalkState));

    /* Invoke an internal method if necessary */

    if (ObjDesc->Method.MethodFlags & AML_METHOD_INTERNAL_ONLY)
    {
        Status = ObjDesc->Method.Implementation (NextWalkState);
    }

    return_ACPI_STATUS (Status);


Cleanup:

    /* On error, we must terminate the method properly */

    AcpiDsTerminateControlMethod (ObjDesc, NextWalkState);
    if (NextWalkState)
    {
        AcpiDsDeleteWalkState (NextWalkState);
    }

    return_ACPI_STATUS (Status);
}


/*******************************************************************************
 *
 * FUNCTION:    AcpiDsRestartControlMethod
 *
 * PARAMETERS:  WalkState           - State for preempted method (caller)
 *              ReturnDesc          - Return value from the called method
 *
 * RETURN:      Status
 *
 * DESCRIPTION: Restart a method that was preempted by another (nested) method
 *              invocation.  Handle the return value (if any) from the callee.
 *
 ******************************************************************************/

ACPI_STATUS
AcpiDsRestartControlMethod (
    ACPI_WALK_STATE         *WalkState,
    ACPI_OPERAND_OBJECT     *ReturnDesc)
{
    ACPI_STATUS             Status;
    int                     SameAsImplicitReturn;


    ACPI_FUNCTION_TRACE_PTR (DsRestartControlMethod, WalkState);


    ACPI_DEBUG_PRINT ((ACPI_DB_DISPATCH,
        "****Restart [%4.4s] Op %p ReturnValueFromCallee %p\n",
        AcpiUtGetNodeName (WalkState->MethodNode),
        WalkState->MethodCallOp, ReturnDesc));

    ACPI_DEBUG_PRINT ((ACPI_DB_DISPATCH,
        "    ReturnFromThisMethodUsed?=%X ResStack %p Walk %p\n",
        WalkState->ReturnUsed,
        WalkState->Results, WalkState));

    /* Did the called method return a value? */

    if (ReturnDesc)
    {
        /* Is the implicit return object the same as the return desc? */

        SameAsImplicitReturn = (WalkState->ImplicitReturnObj == ReturnDesc);

        /* Are we actually going to use the return value? */

        if (WalkState->ReturnUsed)
        {
            /* Save the return value from the previous method */

            Status = AcpiDsResultPush (ReturnDesc, WalkState);
            if (ACPI_FAILURE (Status))
            {
                AcpiUtRemoveReference (ReturnDesc);
                return_ACPI_STATUS (Status);
            }

            /*
             * Save as THIS method's return value in case it is returned
             * immediately to yet another method
             */
            WalkState->ReturnDesc = ReturnDesc;
        }

        /*
         * The following code is the optional support for the so-called
         * "implicit return". Some AML code assumes that the last value of the
         * method is "implicitly" returned to the caller, in the absence of an
         * explicit return value.
         *
         * Just save the last result of the method as the return value.
         *
         * NOTE: this is optional because the ASL language does not actually
         * support this behavior.
         */
        else if (!AcpiDsDoImplicitReturn (ReturnDesc, WalkState, FALSE) ||
                 SameAsImplicitReturn)
        {
            /*
             * Delete the return value if it will not be used by the
             * calling method or remove one reference if the explicit return
             * is the same as the implicit return value.
             */
            AcpiUtRemoveReference (ReturnDesc);
        }
    }

    return_ACPI_STATUS (AE_OK);
}


/*******************************************************************************
 *
 * FUNCTION:    AcpiDsTerminateControlMethod
 *
 * PARAMETERS:  MethodDesc          - Method object
 *              WalkState           - State associated with the method
 *
 * RETURN:      None
 *
 * DESCRIPTION: Terminate a control method.  Delete everything that the method
 *              created, delete all locals and arguments, and delete the parse
 *              tree if requested.
 *
 * MUTEX:       Interpreter is locked
 *
 ******************************************************************************/

void
AcpiDsTerminateControlMethod (
    ACPI_OPERAND_OBJECT     *MethodDesc,
    ACPI_WALK_STATE         *WalkState)
{

    ACPI_FUNCTION_TRACE_PTR (DsTerminateControlMethod, WalkState);


    /* MethodDesc is required, WalkState is optional */

    if (!MethodDesc)
    {
        return_VOID;
    }

    if (WalkState)
    {
        /* Delete all arguments and locals */

        AcpiDsMethodDataDeleteAll (WalkState);

        /*
         * If method is serialized, release the mutex and restore the
         * current sync level for this thread
         */
        if (MethodDesc->Method.Mutex)
        {
            /* Acquisition Depth handles recursive calls */

            MethodDesc->Method.Mutex->Mutex.AcquisitionDepth--;
            if (!MethodDesc->Method.Mutex->Mutex.AcquisitionDepth)
            {
                WalkState->Thread->CurrentSyncLevel =
                    MethodDesc->Method.Mutex->Mutex.OriginalSyncLevel;

                AcpiOsReleaseMutex (MethodDesc->Method.Mutex->Mutex.OsMutex);
                MethodDesc->Method.Mutex->Mutex.ThreadId = 0;
            }
        }

        /*
         * Delete any namespace objects created anywhere within
         * the namespace by the execution of this method
         */
        AcpiNsDeleteNamespaceByOwner (MethodDesc->Method.OwnerId);
    }

    /* Decrement the thread count on the method */

    if (MethodDesc->Method.ThreadCount)
    {
        MethodDesc->Method.ThreadCount--;
    }
    else
    {
        ACPI_ERROR ((AE_INFO,
            "Invalid zero thread count in method"));
    }

    /* Are there any other threads currently executing this method? */

    if (MethodDesc->Method.ThreadCount)
    {
        /*
         * Additional threads. Do not release the OwnerId in this case,
         * we immediately reuse it for the next thread executing this method
         */
        ACPI_DEBUG_PRINT ((ACPI_DB_DISPATCH,
            "*** Completed execution of one thread, %d threads remaining\n",
            MethodDesc->Method.ThreadCount));
    }
    else
    {
        /* This is the only executing thread for this method */

        /*
         * Support to dynamically change a method from NotSerialized to
         * Serialized if it appears that the method is incorrectly written and
         * does not support multiple thread execution. The best example of this
         * is if such a method creates namespace objects and blocks. A second
         * thread will fail with an AE_ALREADY_EXISTS exception
         *
         * This code is here because we must wait until the last thread exits
         * before creating the synchronization semaphore.
         */
        if ((MethodDesc->Method.MethodFlags & AML_METHOD_SERIALIZED) &&
            (!MethodDesc->Method.Mutex))
        {
            (void) AcpiDsCreateMethodMutex (MethodDesc);
        }

        /* No more threads, we can free the OwnerId */

        AcpiUtReleaseOwnerId (&MethodDesc->Method.OwnerId);
    }

    return_VOID;
}