dsutils.c

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/*******************************************************************************
 *
 * Module Name: dsutils - Dispatcher utilities
 *              $Revision: 50 $
 *
 ******************************************************************************/

/*
 *  Copyright (C) 2000 R. Byron Moore
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */


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

#define _COMPONENT          PARSER
	 MODULE_NAME         ("dsutils")


/*******************************************************************************
 *
 * FUNCTION:    Acpi_ds_is_result_used
 *
 * PARAMETERS:  Op
 *              Result_obj
 *              Walk_state
 *
 * RETURN:      Status
 *
 * DESCRIPTION: Check if a result object will be used by the parent
 *
 ******************************************************************************/

u8
acpi_ds_is_result_used (
	ACPI_PARSE_OBJECT       *op,
	ACPI_WALK_STATE         *walk_state)
{
	ACPI_OPCODE_INFO        *parent_info;


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

	if (!op) {
		return (TRUE);
	}


	/*
	 * If there is no parent, the result can't possibly be used!
	 * (An executing method typically has no parent, since each
	 * method is parsed separately)  However, a method that is
	 * invoked from another method has a parent.
	 */
	if (!op->parent) {
		return (FALSE);
	}


	/*
	 * Get info on the parent.  The root Op is AML_SCOPE
	 */

	parent_info = acpi_ps_get_opcode_info (op->parent->opcode);
	if (ACPI_GET_OP_TYPE (parent_info) != ACPI_OP_TYPE_OPCODE) {
		return (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 (ACPI_GET_OP_CLASS (parent_info))
	{
	/*
	 * In these cases, the parent will never use the return object
	 */
	case OPTYPE_CONTROL:        /* IF, ELSE, WHILE only */

		switch (op->parent->opcode)
		{
		case AML_RETURN_OP:

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

			return (TRUE);
			break;

		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 == CONTROL_PREDICATE_EXECUTING) &&
				(walk_state->control_state->control.predicate_op == op))
			{
				return (TRUE);
			}

			break;
		}


		/* Fall through to not used case below */


	case OPTYPE_NAMED_OBJECT:   /* Scope, method, etc. */

		/*
		 * These opcodes allow Term_arg(s) as operands and therefore
		 * method calls.  The result is used.
		 */
		if ((op->parent->opcode == AML_REGION_OP)       ||
			(op->parent->opcode == AML_CREATE_FIELD_OP) ||
			(op->parent->opcode == AML_BIT_FIELD_OP)    ||
			(op->parent->opcode == AML_BYTE_FIELD_OP)   ||
			(op->parent->opcode == AML_WORD_FIELD_OP)   ||
			(op->parent->opcode == AML_DWORD_FIELD_OP)  ||
			(op->parent->opcode == AML_QWORD_FIELD_OP))
		{
			return (TRUE);
		}

		return (FALSE);
		break;

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

	return (TRUE);
}


/*******************************************************************************
 *
 * FUNCTION:    Acpi_ds_delete_result_if_not_used
 *
 * PARAMETERS:  Op
 *              Result_obj
 *              Walk_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 (
	ACPI_PARSE_OBJECT       *op,
	ACPI_OPERAND_OBJECT     *result_obj,
	ACPI_WALK_STATE         *walk_state)
{
	ACPI_OPERAND_OBJECT     *obj_desc;
	ACPI_STATUS             status;


	if (!op) {
		return;
	}

	if (!result_obj) {
		return;
	}


	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_cm_remove_reference (result_obj);
		}
	}

	return;
}


/*******************************************************************************
 *
 * FUNCTION:    Acpi_ds_create_operand
 *
 * PARAMETERS:  Walk_state
 *              Arg
 *
 * 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 (
	ACPI_WALK_STATE         *walk_state,
	ACPI_PARSE_OBJECT       *arg,
	u32                     arg_index)
{
	ACPI_STATUS             status = AE_OK;
	NATIVE_CHAR             *name_string;
	u32                     name_length;
	OBJECT_TYPE_INTERNAL    data_type;
	ACPI_OPERAND_OBJECT     *obj_desc;
	ACPI_PARSE_OBJECT       *parent_op;
	u16                     opcode;
	u32                     flags;
	OPERATING_MODE          interpreter_mode;


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

	if ((arg->opcode == AML_NAMEPATH_OP) &&
		(arg->value.string))
	{
		/* Get the entire name string from the AML stream */

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

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

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

		/*
		 * 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->parent;
		if ((acpi_ps_is_node_op (parent_op->opcode)) &&
			(parent_op->opcode != AML_METHODCALL_OP) &&
			(parent_op->opcode != AML_REGION_OP) &&
			(parent_op->opcode != AML_NAMEPATH_OP))
		{
			/* Enter name into namespace if not found */

			interpreter_mode = IMODE_LOAD_PASS2;
		}

		else {
			/* Return a failure if name not found */

			interpreter_mode = IMODE_EXECUTE;
		}

		status = acpi_ns_lookup (walk_state->scope_info, name_string,
				 ACPI_TYPE_ANY, interpreter_mode,
				 NS_SEARCH_PARENT | NS_DONT_OPEN_SCOPE,
				 walk_state,
				 (ACPI_NAMESPACE_NODE **) &obj_desc);

		/* Free the namestring created above */

		acpi_cm_free (name_string);

		/*
		 * 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->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_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;
			}
		}

		/* Check status from the lookup */

		if (ACPI_FAILURE (status)) {
			return (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 (status);
		}
		DEBUGGER_EXEC (acpi_db_display_argument_object (obj_desc, walk_state));
	}


	else {
		/* Check for null name case */

		if (arg->opcode == AML_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 an Reference for a
			 * placeholder
			 */
			opcode = AML_ZERO_OP;       /* Has no arguments! */

			/*
			 * TBD: [Investigate] anything else needed for the
			 * zero op lvalue?
			 */
		}

		else {
			opcode = arg->opcode;
		}


		/* Get the data type of the argument */

		data_type = acpi_ds_map_opcode_to_data_type (opcode, &flags);
		if (data_type == INTERNAL_TYPE_INVALID) {
			return (AE_NOT_IMPLEMENTED);
		}

		if (flags & OP_HAS_RETURN_VALUE) {
			DEBUGGER_EXEC (acpi_db_display_argument_object (walk_state->operands [walk_state->num_operands - 1], walk_state));

			/*
			 * Use value that was already previously returned