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[linux-2.6.9-moxart.git] / drivers / acpi / dispatcher / dsutils.c

/*******************************************************************************
 *
 * Module Name: dsutils - Dispatcher utilities
 *
 ******************************************************************************/

/*
 * Copyright (C) 2000 - 2004, R. Byron Moore
 * All rights reserved.
 *
 * 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.
 *
 * Alternatively, this software may be distributed under the terms of the
 * GNU General Public License ("GPL") version 2 as published by the Free
 * Software Foundation.
 *
 * NO WARRANTY
 * 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 MERCHANTIBILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * HOLDERS OR CONTRIBUTORS BE LIABLE FOR 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 DAMAGES.
 */


#include <acpi/acpi.h>
#include <acpi/acparser.h>
#include <acpi/amlcode.h>
#include <acpi/acdispat.h>
#include <acpi/acinterp.h>
#include <acpi/acnamesp.h>
#include <acpi/acdebug.h>

#define _COMPONENT          ACPI_DISPATCHER
         ACPI_MODULE_NAME    ("dsutils")


#ifndef ACPI_NO_METHOD_EXECUTION

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

u8
acpi_ds_is_result_used (
        union acpi_parse_object         *op,
        struct acpi_walk_state          *walk_state)
{
        const struct acpi_opcode_info   *parent_info;


        ACPI_FUNCTION_TRACE_PTR ("ds_is_result_used", op);


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

        if (!op) {
                ACPI_DEBUG_PRINT ((ACPI_DB_ERROR, "Null Op\n"));
                return_VALUE (TRUE);
        }

        /*
         * If there is no parent, we are executing at the method level.
         * An executing method typically has no parent, since each method
         * is parsed separately.
         */
        if (!op->common.parent) {
                /*
                 * If this is the last statement in the method, we know it 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.
                 */
                if ((acpi_gbl_enable_interpreter_slack) &&
                        (walk_state->parser_state.aml >= walk_state->parser_state.aml_end)) {
                        ACPI_DEBUG_PRINT ((ACPI_DB_DISPATCH,
                                        "Result of [%s] will be implicitly returned\n",
                                        acpi_ps_get_opcode_name (op->common.aml_opcode)));

                        /* Use the top of the result stack as the implicit return value */

                        walk_state->return_desc = walk_state->results->results.obj_desc[0];
                        return_VALUE (TRUE);
                }

                /* No parent, the return value cannot possibly be used */

                return_VALUE (FALSE);
        }

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

        parent_info = acpi_ps_get_opcode_info (op->common.parent->common.aml_opcode);
        if (parent_info->class == AML_CLASS_UNKNOWN) {
                ACPI_DEBUG_PRINT ((ACPI_DB_ERROR, "Unknown parent opcode. Op=%p\n", op));
                return_VALUE (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 (parent_info->class) {
        case AML_CLASS_CONTROL:

                switch (op->common.parent->common.aml_opcode) {
                case AML_RETURN_OP:

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

                        goto result_used;

                case AML_IF_OP:
                case AML_WHILE_OP:

                        /*
                         * If we are executing the predicate AND this is the predicate op,
                         * we will use the return value
                         */
                        if ((walk_state->control_state->common.state == ACPI_CONTROL_PREDICATE_EXECUTING) &&
                                (walk_state->control_state->control.predicate_op == op)) {
                                goto result_used;
                        }
                        break;

                default:
                        /* Ignore other control opcodes */
                        break;
                }

                /* The general control opcode returns no result */

                goto result_not_used;


        case AML_CLASS_CREATE:

                /*
                 * These opcodes allow term_arg(s) as operands and therefore
                 * the operands can be method calls.  The result is used.
                 */
                goto result_used;


        case AML_CLASS_NAMED_OBJECT:

                if ((op->common.parent->common.aml_opcode == AML_REGION_OP)      ||
                        (op->common.parent->common.aml_opcode == AML_DATA_REGION_OP) ||
                        (op->common.parent->common.aml_opcode == AML_PACKAGE_OP)     ||
                        (op->common.parent->common.aml_opcode == AML_VAR_PACKAGE_OP) ||
                        (op->common.parent->common.aml_opcode == AML_BUFFER_OP)      ||
                        (op->common.parent->common.aml_opcode == AML_INT_EVAL_SUBTREE_OP)) {
                        /*
                         * These opcodes allow term_arg(s) as operands and therefore
                         * the operands can be method calls.  The result is used.
                         */
                        goto result_used;
                }

                goto result_not_used;


        default:

                /*
                 * In all other cases. the parent will actually use the return
                 * object, so keep it.
                 */
                goto result_used;
        }


result_used:
        ACPI_DEBUG_PRINT ((ACPI_DB_DISPATCH, "Result of [%s] used by Parent [%s] Op=%p\n",
                        acpi_ps_get_opcode_name (op->common.aml_opcode),
                        acpi_ps_get_opcode_name (op->common.parent->common.aml_opcode), op));

        return_VALUE (TRUE);


result_not_used:
        ACPI_DEBUG_PRINT ((ACPI_DB_DISPATCH, "Result of [%s] not used by Parent [%s] Op=%p\n",
                        acpi_ps_get_opcode_name (op->common.aml_opcode),
                        acpi_ps_get_opcode_name (op->common.parent->common.aml_opcode), op));

        return_VALUE (FALSE);
}


/*******************************************************************************
 *
 * FUNCTION:    acpi_ds_delete_result_if_not_used
 *
 * PARAMETERS:  Op              - Current parse Op
 *              result_obj      - Result of the operation
 *              walk_state      - Current state
 *
 * RETURN:      Status
 *
 * DESCRIPTION: Used after interpretation of an opcode.  If there is an internal
 *              result descriptor, check if the parent opcode will actually use
 *              this result.  If not, delete the result now so that it will
 *              not become orphaned.
 *
 ******************************************************************************/

void
acpi_ds_delete_result_if_not_used (
        union acpi_parse_object         *op,
        union acpi_operand_object       *result_obj,
        struct acpi_walk_state          *walk_state)
{
        union acpi_operand_object       *obj_desc;
        acpi_status                     status;


        ACPI_FUNCTION_TRACE_PTR ("ds_delete_result_if_not_used", result_obj);


        if (!op) {
                ACPI_DEBUG_PRINT ((ACPI_DB_ERROR, "Null Op\n"));
                return_VOID;
        }

        if (!result_obj) {
                return_VOID;
        }

        if (!acpi_ds_is_result_used (op, walk_state)) {
                /*
                 * Must pop the result stack (obj_desc should be equal to result_obj)
                 */
                status = acpi_ds_result_pop (&obj_desc, walk_state);
                if (ACPI_SUCCESS (status)) {
                        acpi_ut_remove_reference (result_obj);
                }
        }

        return_VOID;
}


/*******************************************************************************
 *
 * FUNCTION:    acpi_ds_resolve_operands
 *
 * PARAMETERS:  walk_state          - Current walk state with operands on stack
 *
 * RETURN:      Status
 *
 * DESCRIPTION: Resolve all operands to their values.  Used to prepare
 *              arguments to a control method invocation (a call from one
 *              method to another.)
 *
 ******************************************************************************/

acpi_status
acpi_ds_resolve_operands (
        struct acpi_walk_state          *walk_state)
{
        u32                             i;
        acpi_status                     status = AE_OK;


        ACPI_FUNCTION_TRACE_PTR ("ds_resolve_operands", walk_state);


        /*
         * Attempt to resolve each of the valid operands
         * Method arguments are passed by reference, not by value.  This means
         * that the actual objects are passed, not copies of the objects.
         */
        for (i = 0; i < walk_state->num_operands; i++) {
                status = acpi_ex_resolve_to_value (&walk_state->operands[i], walk_state);
                if (ACPI_FAILURE (status)) {
                        break;
                }
        }

        return_ACPI_STATUS (status);
}


/*******************************************************************************
 *
 * FUNCTION:    acpi_ds_clear_operands
 *
 * PARAMETERS:  walk_state          - Current walk state with operands on stack
 *
 * RETURN:      None
 *
 * DESCRIPTION: Clear all operands on the current walk state operand stack.
 *
 ******************************************************************************/

void
acpi_ds_clear_operands (
        struct acpi_walk_state          *walk_state)
{
        u32                             i;


        ACPI_FUNCTION_TRACE_PTR ("acpi_ds_clear_operands", walk_state);


        /*
         * Remove a reference on each operand on the stack
         */
        for (i = 0; i < walk_state->num_operands; i++) {
                /*
                 * Remove a reference to all operands, including both
                 * "Arguments" and "Targets".
                 */
                acpi_ut_remove_reference (walk_state->operands[i]);
                walk_state->operands[i] = NULL;
        }

        walk_state->num_operands = 0;
        return_VOID;
}
#endif


/*******************************************************************************
 *
 * FUNCTION:    acpi_ds_create_operand
 *
 * PARAMETERS:  walk_state      - Current walk state
 *              Arg             - Parse object for the argument
 *              arg_index       - Which argument (zero based)
 *
 * RETURN:      Status
 *
 * DESCRIPTION: Translate a parse tree object that is an argument to an AML
 *              opcode to the equivalent interpreter object.  This may include
 *              looking up a name or entering a new name into the internal
 *              namespace.
 *
 ******************************************************************************/

acpi_status
acpi_ds_create_operand (
        struct acpi_walk_state          *walk_state,
        union acpi_parse_object         *arg,
        u32                             arg_index)
{
        acpi_status                     status = AE_OK;
        char                            *name_string;
        u32                             name_length;
        union acpi_operand_object       *obj_desc;
        union acpi_parse_object         *parent_op;
        u16                             opcode;
        acpi_interpreter_mode           interpreter_mode;
        const struct acpi_opcode_info   *op_info;


        ACPI_FUNCTION_TRACE_PTR ("ds_create_operand", arg);


        /* A valid name must be looked up in the namespace */

        if ((arg->common.aml_opcode == AML_INT_NAMEPATH_OP) &&
                (arg->common.value.string)) {
                ACPI_DEBUG_PRINT ((ACPI_DB_DISPATCH, "Getting a name: Arg=%p\n", arg));

                /* Get the entire name string from the AML stream */

                status = acpi_ex_get_name_string (ACPI_TYPE_ANY, arg->common.value.buffer,
                                  &name_string, &name_length);

                if (ACPI_FAILURE (status)) {
                        return_ACPI_STATUS (status);
                }

                /*
                 * All prefixes have been handled, and the name is
                 * in name_string
                 */


                /*
                 * Special handling for buffer_field declarations. This is a deferred
                 * opcode that unfortunately defines the field name as the last
                 * parameter instead of the first.  We get here when we are performing
                 * the deferred execution, so the actual name of the field is already
                 * in the namespace.  We don't want to attempt to look it up again
                 * because we may be executing in a different scope than where the
                 * actual opcode exists.
                 */
                if ((walk_state->deferred_node) &&
                        (walk_state->deferred_node->type == ACPI_TYPE_BUFFER_FIELD) &&
                        (arg_index != 0)) {
                        obj_desc = ACPI_CAST_PTR (union acpi_operand_object, walk_state->deferred_node);
                        status = AE_OK;
                }
                else    /* All other opcodes */ {
                        /*
                         * Differentiate between a namespace "create" operation
                         * versus a "lookup" operation (IMODE_LOAD_PASS2 vs.
                         * IMODE_EXECUTE) in order to support the creation of
                         * namespace objects during the execution of control methods.
                         */
                        parent_op = arg->common.parent;
                        op_info = acpi_ps_get_opcode_info (parent_op->common.aml_opcode);
                        if ((op_info->flags & AML_NSNODE) &&
                                (parent_op->common.aml_opcode != AML_INT_METHODCALL_OP) &&
                                (parent_op->common.aml_opcode != AML_REGION_OP) &&
                                (parent_op->common.aml_opcode != AML_INT_NAMEPATH_OP)) {
                                /* Enter name into namespace if not found */

                                interpreter_mode = ACPI_IMODE_LOAD_PASS2;
                        }
                        else {
                                /* Return a failure if name not found */

                                interpreter_mode = ACPI_IMODE_EXECUTE;
                        }

                        status = acpi_ns_lookup (walk_state->scope_info, name_string,
                                         ACPI_TYPE_ANY, interpreter_mode,
                                         ACPI_NS_SEARCH_PARENT | ACPI_NS_DONT_OPEN_SCOPE,
                                         walk_state,
                                         ACPI_CAST_INDIRECT_PTR (struct acpi_namespace_node, &obj_desc));
                        /*
                         * The only case where we pass through (ignore) a NOT_FOUND
                         * error is for the cond_ref_of opcode.
                         */
                        if (status == AE_NOT_FOUND) {
                                if (parent_op->common.aml_opcode == AML_COND_REF_OF_OP) {
                                        /*
                                         * For the Conditional Reference op, it's OK if
                                         * the name is not found;  We just need a way to
                                         * indicate this to the interpreter, set the
                                         * object to the root
                                         */
                                        obj_desc = ACPI_CAST_PTR (union acpi_operand_object, acpi_gbl_root_node);
                                        status = AE_OK;
                                }
                                else {
                                        /*
                                         * We just plain didn't find it -- which is a
                                         * very serious error at this point
                                         */
                                        status = AE_AML_NAME_NOT_FOUND;
                                }
                        }

                        if (ACPI_FAILURE (status)) {
                                ACPI_REPORT_NSERROR (name_string, status);
                        }
                }

                /* Free the namestring created above */

                ACPI_MEM_FREE (name_string);

                /* Check status from the lookup */

                if (ACPI_FAILURE (status)) {
                        return_ACPI_STATUS (status);
                }

                /* Put the resulting object onto the current object stack */

                status = acpi_ds_obj_stack_push (obj_desc, walk_state);
                if (ACPI_FAILURE (status)) {
                        return_ACPI_STATUS (status);
                }
                ACPI_DEBUGGER_EXEC (acpi_db_display_argument_object (obj_desc, walk_state));
        }
        else {
                /* Check for null name case */

                if (arg->common.aml_opcode == AML_INT_NAMEPATH_OP) {
                        /*
                         * If the name is null, this means that this is an
                         * optional result parameter that was not specified
                         * in the original ASL.  Create a Zero Constant for a
                         * placeholder.  (Store to a constant is a Noop.)
                         */
                        opcode = AML_ZERO_OP;       /* Has no arguments! */

                        ACPI_DEBUG_PRINT ((ACPI_DB_DISPATCH, "Null namepath: Arg=%p\n", arg));
                }
                else {
                        opcode = arg->common.aml_opcode;
                }

                /* Get the object type of the argument */

                op_info = acpi_ps_get_opcode_info (opcode);
                if (op_info->object_type == ACPI_TYPE_INVALID) {
                        return_ACPI_STATUS (AE_NOT_IMPLEMENTED);
                }

                if (op_info->flags & AML_HAS_RETVAL) {
                        ACPI_DEBUG_PRINT ((ACPI_DB_DISPATCH,
                                "Argument previously created, already stacked \n"));

                        ACPI_DEBUGGER_EXEC (acpi_db_display_argument_object (
                                walk_state->operands [walk_state->num_operands - 1], walk_state));

                        /*
                         * Use value that was already previously returned
                         * by the evaluation of this argument
                         */
                        status = acpi_ds_result_pop_from_bottom (&obj_desc, walk_state);
                        if (ACPI_FAILURE (status)) {
                                /*
                                 * Only error is underflow, and this indicates
                                 * a missing or null operand!
                                 */
                                ACPI_DEBUG_PRINT ((ACPI_DB_ERROR, "Missing or null operand, %s\n",
                                        acpi_format_exception (status)));
                                return_ACPI_STATUS (status);
                        }
                }
                else {
                        /* Create an ACPI_INTERNAL_OBJECT for the argument */

                        obj_desc = acpi_ut_create_internal_object (op_info->object_type);
                        if (!obj_desc) {
                                return_ACPI_STATUS (AE_NO_MEMORY);
                        }

                        /* Initialize the new object */

                        status = acpi_ds_init_object_from_op (walk_state, arg,
                                         opcode, &obj_desc);
                        if (ACPI_FAILURE (status)) {
                                acpi_ut_delete_object_desc (obj_desc);
                                return_ACPI_STATUS (status);
                        }
                }

                /* Put the operand object on the object stack */

                status = acpi_ds_obj_stack_push (obj_desc, walk_state);
                if (ACPI_FAILURE (status)) {
                        return_ACPI_STATUS (status);
                }

                ACPI_DEBUGGER_EXEC (acpi_db_display_argument_object (obj_desc, walk_state));
        }

        return_ACPI_STATUS (AE_OK);
}


/*******************************************************************************
 *
 * FUNCTION:    acpi_ds_create_operands
 *
 * PARAMETERS:  first_arg           - First argument of a parser argument tree
 *
 * RETURN:      Status
 *
 * DESCRIPTION: Convert an operator's arguments from a parse tree format to
 *              namespace objects and place those argument object on the object
 *              stack in preparation for evaluation by the interpreter.
 *
 ******************************************************************************/

acpi_status
acpi_ds_create_operands (
        struct acpi_walk_state          *walk_state,
        union acpi_parse_object         *first_arg)
{
        acpi_status                     status = AE_OK;
        union acpi_parse_object         *arg;
        u32                             arg_count = 0;


        ACPI_FUNCTION_TRACE_PTR ("ds_create_operands", first_arg);


        /* For all arguments in the list... */

        arg = first_arg;
        while (arg) {
                status = acpi_ds_create_operand (walk_state, arg, arg_count);
                if (ACPI_FAILURE (status)) {
                        goto cleanup;
                }

                ACPI_DEBUG_PRINT ((ACPI_DB_DISPATCH, "Arg #%d (%p) done, Arg1=%p\n",
                        arg_count, arg, first_arg));

                /* Move on to next argument, if any */

                arg = arg->common.next;
                arg_count++;
        }

        return_ACPI_STATUS (status);


cleanup:
        /*
         * We must undo everything done above; meaning that we must
         * pop everything off of the operand stack and delete those
         * objects
         */
        (void) acpi_ds_obj_stack_pop_and_delete (arg_count, walk_state);

        ACPI_DEBUG_PRINT ((ACPI_DB_ERROR, "While creating Arg %d - %s\n",
                (arg_count + 1), acpi_format_exception (status)));
        return_ACPI_STATUS (status);
}