psparse.c

acpi tools for linux include acpiexec and acpixtract

 *
 * FUNCTION:    AcpiPsNextParseState
 *
 * PARAMETERS:  WalkState           - Current state
 *              Op                  - Current parse op
 *              CallbackStatus      - Status from previous operation
 *
 * RETURN:      Status
 *
 * DESCRIPTION: Update the parser state based upon the return exception from
 *              the parser callback.
 *
 ******************************************************************************/

ACPI_STATUS
AcpiPsNextParseState (
    ACPI_WALK_STATE         *WalkState,
    ACPI_PARSE_OBJECT       *Op,
    ACPI_STATUS             CallbackStatus)
{
    ACPI_PARSE_STATE        *ParserState = &WalkState->ParserState;
    ACPI_STATUS             Status = AE_CTRL_PENDING;


    ACPI_FUNCTION_TRACE_PTR (PsNextParseState, Op);


    switch (CallbackStatus)
    {
    case AE_CTRL_TERMINATE:
        /*
         * A control method was terminated via a RETURN statement.
         * The walk of this method is complete.
         */
        ParserState->Aml = ParserState->AmlEnd;
        Status = AE_CTRL_TERMINATE;
        break;


    case AE_CTRL_BREAK:

        ParserState->Aml = WalkState->AmlLastWhile;
        WalkState->ControlState->Common.Value = FALSE;
        Status = AE_CTRL_BREAK;
        break;


    case AE_CTRL_CONTINUE:

        ParserState->Aml = WalkState->AmlLastWhile;
        Status = AE_CTRL_CONTINUE;
        break;


    case AE_CTRL_PENDING:

        ParserState->Aml = WalkState->AmlLastWhile;
        break;

#if 0
    case AE_CTRL_SKIP:

        ParserState->Aml = ParserState->Scope->ParseScope.PkgEnd;
        Status = AE_OK;
        break;
#endif

    case AE_CTRL_TRUE:
        /*
         * Predicate of an IF was true, and we are at the matching ELSE.
         * Just close out this package
         */
        ParserState->Aml = AcpiPsGetNextPackageEnd (ParserState);
        Status = AE_CTRL_PENDING;
        break;


    case AE_CTRL_FALSE:
        /*
         * Either an IF/WHILE Predicate was false or we encountered a BREAK
         * opcode.  In both cases, we do not execute the rest of the
         * package;  We simply close out the parent (finishing the walk of
         * this branch of the tree) and continue execution at the parent
         * level.
         */
        ParserState->Aml = ParserState->Scope->ParseScope.PkgEnd;

        /* In the case of a BREAK, just force a predicate (if any) to FALSE */

        WalkState->ControlState->Common.Value = FALSE;
        Status = AE_CTRL_END;
        break;


    case AE_CTRL_TRANSFER:

        /* A method call (invocation) -- transfer control */

        Status = AE_CTRL_TRANSFER;
        WalkState->PrevOp = Op;
        WalkState->MethodCallOp = Op;
        WalkState->MethodCallNode = (Op->Common.Value.Arg)->Common.Node;

        /* Will return value (if any) be used by the caller? */

        WalkState->ReturnUsed = AcpiDsIsResultUsed (Op, WalkState);
        break;


    default:

        Status = CallbackStatus;
        if ((CallbackStatus & AE_CODE_MASK) == AE_CODE_CONTROL)
        {
            Status = AE_OK;
        }
        break;
    }

    return_ACPI_STATUS (Status);
}


/*******************************************************************************
 *
 * FUNCTION:    AcpiPsParseAml
 *
 * PARAMETERS:  WalkState       - Current state
 *
 *
 * RETURN:      Status
 *
 * DESCRIPTION: Parse raw AML and return a tree of ops
 *
 ******************************************************************************/

ACPI_STATUS
AcpiPsParseAml (
    ACPI_WALK_STATE         *WalkState)
{
    ACPI_STATUS             Status;
    ACPI_THREAD_STATE       *Thread;
    ACPI_THREAD_STATE       *PrevWalkList = AcpiGbl_CurrentWalkList;
    ACPI_WALK_STATE         *PreviousWalkState;


    ACPI_FUNCTION_TRACE (PsParseAml);

    ACPI_DEBUG_PRINT ((ACPI_DB_PARSE,
        "Entered with WalkState=%p Aml=%p size=%X\n",
        WalkState, WalkState->ParserState.Aml,
        WalkState->ParserState.AmlSize));


    /* Create and initialize a new thread state */

    Thread = AcpiUtCreateThreadState ();
    if (!Thread)
    {
        AcpiDsDeleteWalkState (WalkState);
        return_ACPI_STATUS (AE_NO_MEMORY);
    }

    WalkState->Thread = Thread;

    /*
     * If executing a method, the starting SyncLevel is this method's
     * SyncLevel
     */
    if (WalkState->MethodDesc)
    {
        WalkState->Thread->CurrentSyncLevel = WalkState->MethodDesc->Method.SyncLevel;
    }

    AcpiDsPushWalkState (WalkState, Thread);

    /*
     * This global allows the AML debugger to get a handle to the currently
     * executing control method.
     */
    AcpiGbl_CurrentWalkList = Thread;

    /*
     * Execute the walk loop as long as there is a valid Walk State.  This
     * handles nested control method invocations without recursion.
     */
    ACPI_DEBUG_PRINT ((ACPI_DB_PARSE, "State=%p\n", WalkState));

    Status = AE_OK;
    while (WalkState)
    {
        if (ACPI_SUCCESS (Status))
        {
            /*
             * The ParseLoop executes AML until the method terminates
             * or calls another method.
             */
            Status = AcpiPsParseLoop (WalkState);
        }

        ACPI_DEBUG_PRINT ((ACPI_DB_PARSE,
            "Completed one call to walk loop, %s State=%p\n",
            AcpiFormatException (Status), WalkState));

        if (Status == AE_CTRL_TRANSFER)
        {
            /*
             * A method call was detected.
             * Transfer control to the called control method
             */
            Status = AcpiDsCallControlMethod (Thread, WalkState, NULL);
            if (ACPI_FAILURE (Status))
            {
                Status = AcpiDsMethodError (Status, WalkState);
            }

            /*
             * If the transfer to the new method method call worked, a new walk
             * state was created -- get it
             */
            WalkState = AcpiDsGetCurrentWalkState (Thread);
            continue;
        }
        else if (Status == AE_CTRL_TERMINATE)
        {
            Status = AE_OK;
        }
        else if ((Status != AE_OK) && (WalkState->MethodDesc))
        {
            /* Either the method parse or actual execution failed */

            ACPI_ERROR_METHOD ("Method parse/execution failed",
                WalkState->MethodNode, NULL, Status);

            /* Check for possible multi-thread reentrancy problem */

            if ((Status == AE_ALREADY_EXISTS) &&
                (!WalkState->MethodDesc->Method.Mutex))
            {
                ACPI_INFO ((AE_INFO,
                    "Marking method %4.4s as Serialized because of AE_ALREADY_EXISTS error",
                    WalkState->MethodNode->Name.Ascii));

                /*
                 * Method tried to create an object twice. The probable cause is
                 * that the method cannot handle reentrancy.
                 *
                 * The method is marked NotSerialized, but it tried to create
                 * a named object, causing the second thread entrance to fail.
                 * Workaround this problem by marking the method permanently
                 * as Serialized.
                 */
                WalkState->MethodDesc->Method.MethodFlags |= AML_METHOD_SERIALIZED;
                WalkState->MethodDesc->Method.SyncLevel = 0;
            }
        }

        /* We are done with this walk, move on to the parent if any */

        WalkState = AcpiDsPopWalkState (Thread);

        /* Reset the current scope to the beginning of scope stack */

        AcpiDsScopeStackClear (WalkState);

        /*
         * If we just returned from the execution of a control method or if we
         * encountered an error during the method parse phase, there's lots of
         * cleanup to do
         */
        if (((WalkState->ParseFlags & ACPI_PARSE_MODE_MASK) == ACPI_PARSE_EXECUTE) ||
            (ACPI_FAILURE (Status)))
        {
            AcpiDsTerminateControlMethod (WalkState->MethodDesc, WalkState);
        }

        /* Delete this walk state and all linked control states */

        AcpiPsCleanupScope (&WalkState->ParserState);
        PreviousWalkState = WalkState;

        ACPI_DEBUG_PRINT ((ACPI_DB_PARSE,
            "ReturnValue=%p, ImplicitValue=%p State=%p\n",
            WalkState->ReturnDesc, WalkState->ImplicitReturnObj, WalkState));

        /* Check if we have restarted a preempted walk */

        WalkState = AcpiDsGetCurrentWalkState (Thread);
        if (WalkState)
        {
            if (ACPI_SUCCESS (Status))
            {
                /*
                 * There is another walk state, restart it.
                 * If the method return value is not used by the parent,
                 * The object is deleted
                 */
                if (!PreviousWalkState->ReturnDesc)
                {
                    /*
                     * In slack mode execution, if there is no return value
                     * we should implicitly return zero (0) as a default value.
                     */
                    if (AcpiGbl_EnableInterpreterSlack &&
                        !PreviousWalkState->ImplicitReturnObj)
                    {
                        PreviousWalkState->ImplicitReturnObj =
                            AcpiUtCreateInternalObject (ACPI_TYPE_INTEGER);
                        if (!PreviousWalkState->ImplicitReturnObj)
                        {
                            return_ACPI_STATUS (AE_NO_MEMORY);
                        }

                        PreviousWalkState->ImplicitReturnObj->Integer.Value = 0;
                    }

                    /* Restart the calling control method */

                    Status = AcpiDsRestartControlMethod (WalkState,
                                PreviousWalkState->ImplicitReturnObj);
                }
                else
                {
                    /*
                     * We have a valid return value, delete any implicit
                     * return value.
                     */
                    AcpiDsClearImplicitReturn (PreviousWalkState);

                    Status = AcpiDsRestartControlMethod (WalkState,
                                PreviousWalkState->ReturnDesc);
                }
                if (ACPI_SUCCESS (Status))
                {
                    WalkState->WalkType |= ACPI_WALK_METHOD_RESTART;
                }
            }
            else
            {
                /* On error, delete any return object */

                AcpiUtRemoveReference (PreviousWalkState->ReturnDesc);
            }
        }

        /*
         * Just completed a 1st-level method, save the final internal return
         * value (if any)
         */
        else if (PreviousWalkState->CallerReturnDesc)
        {
            if (PreviousWalkState->ImplicitReturnObj)
            {
                *(PreviousWalkState->CallerReturnDesc) =
                    PreviousWalkState->ImplicitReturnObj;
            }
            else
            {
                 /* NULL if no return value */

                *(PreviousWalkState->CallerReturnDesc) =
                    PreviousWalkState->ReturnDesc;
            }
        }
        else
        {
            if (PreviousWalkState->ReturnDesc)
            {
                /* Caller doesn't want it, must delete it */

                AcpiUtRemoveReference (PreviousWalkState->ReturnDesc);
            }
            if (PreviousWalkState->ImplicitReturnObj)
            {
                /* Caller doesn't want it, must delete it */

                AcpiUtRemoveReference (PreviousWalkState->ImplicitReturnObj);
            }
        }

        AcpiDsDeleteWalkState (PreviousWalkState);
    }

    /* Normal exit */

    AcpiExReleaseAllMutexes (Thread);
    AcpiUtDeleteGenericState (ACPI_CAST_PTR (ACPI_GENERIC_STATE, Thread));
    AcpiGbl_CurrentWalkList = PrevWalkList;
    return_ACPI_STATUS (Status);
}