psparse.c

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/******************************************************************************
 *
 * Module Name: psparse - Parser top level AML parse routines
 *              $Revision: 121 $
 *
 *****************************************************************************/

/*
 *  Copyright (C) 2000 - 2002, 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
 */


/*
 * Parse the AML and build an operation tree as most interpreters,
 * like Perl, do.  Parsing is done by hand rather than with a YACC
 * generated parser to tightly constrain stack and dynamic memory
 * usage.  At the same time, parsing is kept flexible and the code
 * fairly compact by parsing based on a list of AML opcode
 * templates in Aml_op_info[]
 */

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

#define _COMPONENT          ACPI_PARSER
	 ACPI_MODULE_NAME    ("psparse")


u32                         acpi_gbl_depth = 0;
extern u32                  acpi_gbl_scope_depth;


/*******************************************************************************
 *
 * FUNCTION:    Acpi_ps_get_opcode_size
 *
 * PARAMETERS:  Opcode          - An AML opcode
 *
 * RETURN:      Size of the opcode, in bytes (1 or 2)
 *
 * DESCRIPTION: Get the size of the current opcode.
 *
 ******************************************************************************/

u32
acpi_ps_get_opcode_size (
	u32                     opcode)
{

	/* Extended (2-byte) opcode if > 255 */

	if (opcode > 0x00FF) {
		return (2);
	}

	/* Otherwise, just a single byte opcode */

	return (1);
}


/*******************************************************************************
 *
 * FUNCTION:    Acpi_ps_peek_opcode
 *
 * PARAMETERS:  Parser_state        - A parser state object
 *
 * RETURN:      Status
 *
 * DESCRIPTION: Get next AML opcode (without incrementing AML pointer)
 *
 ******************************************************************************/

u16
acpi_ps_peek_opcode (
	acpi_parse_state        *parser_state)
{
	u8                      *aml;
	u16                     opcode;


	aml = parser_state->aml;
	opcode = (u16) ACPI_GET8 (aml);


	if (opcode == AML_EXTOP) {
		/* Extended opcode */

		aml++;
		opcode = (u16) ((opcode << 8) | ACPI_GET8 (aml));
	}

	return (opcode);
}


/*******************************************************************************
 *
 * FUNCTION:    Acpi_ps_find_object
 *
 * PARAMETERS:  Opcode          - Current opcode
 *              Parser_state    - Current state
 *              Walk_state      - Current state
 *              *Op             - Where found/new op is returned
 *
 * RETURN:      Status
 *
 * DESCRIPTION: Find a named object.  Two versions - one to search the parse
 *              tree (for parser-only applications such as acpidump), another
 *              to search the ACPI internal namespace (the parse tree may no
 *              longer exist)
 *
 ******************************************************************************/

#ifdef PARSER_ONLY

acpi_status
acpi_ps_find_object (
	acpi_walk_state         *walk_state,
	acpi_parse_object       **out_op)
{
	NATIVE_CHAR             *path;


	/* We are only interested in opcodes that have an associated name */

	if (!(walk_state->op_info->flags & AML_NAMED)) {
		*out_op = walk_state->op;
		return (AE_OK);
	}

	/* Find the name in the parse tree */

	path = acpi_ps_get_next_namestring (&walk_state->parser_state);

	*out_op = acpi_ps_find (acpi_ps_get_parent_scope (&walk_state->parser_state),
			  path, walk_state->opcode, 1);

	if (!(*out_op)) {
		return (AE_NOT_FOUND);
	}

	return (AE_OK);
}

#endif


/*******************************************************************************
 *
 * FUNCTION:    Acpi_ps_complete_this_op
 *
 * PARAMETERS:  Walk_state      - Current State
 *              Op              - Op to complete
 *
 * RETURN:      TRUE if Op and subtree was deleted
 *
 * DESCRIPTION: Perform any cleanup at the completion of an Op.
 *
 ******************************************************************************/

u8
acpi_ps_complete_this_op (
	acpi_walk_state         *walk_state,
	acpi_parse_object       *op)
{
#ifndef PARSER_ONLY
	acpi_parse_object       *prev;
	acpi_parse_object       *next;
	const acpi_opcode_info  *parent_info;
	acpi_parse_object       *replacement_op = NULL;


	ACPI_FUNCTION_TRACE_PTR ("Ps_complete_this_op", op);


	/* Check for null Op, can happen if AML code is corrupt */

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

	/* Delete this op and the subtree below it if asked to */

	if (((walk_state->parse_flags & ACPI_PARSE_TREE_MASK) == ACPI_PARSE_DELETE_TREE) &&
		(walk_state->op_info->class != AML_CLASS_ARGUMENT)) {
		/* Make sure that we only delete this subtree */

		if (op->parent) {
			/*
			 * Check if we need to replace the operator and its subtree
			 * with a return value op (placeholder op)
			 */
			parent_info = acpi_ps_get_opcode_info (op->parent->opcode);

			switch (parent_info->class) {
			case AML_CLASS_CONTROL:
				break;

			case AML_CLASS_CREATE:

				/*
				 * These opcodes contain Term_arg operands. The current
				 * op must be replaced by a placeholder return op
				 */
				replacement_op = acpi_ps_alloc_op (AML_INT_RETURN_VALUE_OP);
				if (!replacement_op) {
					return_VALUE (FALSE);
				}
				break;

			case AML_CLASS_NAMED_OBJECT:

				/*
				 * These opcodes contain Term_arg operands. The current
				 * op must be replaced by a placeholder return op
				 */
				if ((op->parent->opcode == AML_REGION_OP)       ||
					(op->parent->opcode == AML_DATA_REGION_OP)  ||
					(op->parent->opcode == AML_BUFFER_OP)       ||
					(op->parent->opcode == AML_PACKAGE_OP)      ||
					(op->parent->opcode == AML_VAR_PACKAGE_OP)) {
					replacement_op = acpi_ps_alloc_op (AML_INT_RETURN_VALUE_OP);
					if (!replacement_op) {
						return_VALUE (FALSE);
					}
				}

				if ((op->parent->opcode == AML_NAME_OP) &&
					(walk_state->descending_callback != acpi_ds_exec_begin_op)) {
					if ((op->opcode == AML_BUFFER_OP) ||
						(op->opcode == AML_PACKAGE_OP) ||
						(op->opcode == AML_VAR_PACKAGE_OP)) {
						replacement_op = acpi_ps_alloc_op (op->opcode);
						if (!replacement_op) {
							return_VALUE (FALSE);
						}

						((acpi_parse2_object *) replacement_op)->data =
							((acpi_parse2_object *) op)->data;
						((acpi_parse2_object *) replacement_op)->length =
							((acpi_parse2_object *) op)->length;
					}
				}
				break;

			default:
				replacement_op = acpi_ps_alloc_op (AML_INT_RETURN_VALUE_OP);
				if (!replacement_op) {
					return_VALUE (FALSE);
				}
			}

			/* We must unlink this op from the parent tree */

			prev = op->parent->value.arg;
			if (prev == op) {
				/* This op is the first in the list */

				if (replacement_op) {
					replacement_op->parent   = op->parent;
					replacement_op->value.arg = NULL;
					replacement_op->node     = op->node;
					op->parent->value.arg    = replacement_op;
					replacement_op->next     = op->next;
				}
				else {
					op->parent->value.arg    = op->next;
				}
			}

			/* Search the parent list */

			else while (prev) {
				/* Traverse all siblings in the parent's argument list */

				next = prev->next;
				if (next == op) {
					if (replacement_op) {
						replacement_op->parent   = op->parent;
						replacement_op->value.arg = NULL;
						replacement_op->node     = op->node;
						prev->next               = replacement_op;
						replacement_op->next     = op->next;
						next = NULL;
					}
					else {
						prev->next = op->next;
						next = NULL;
					}
				}

				prev = next;
			}
		}

		/* Now we can actually delete the subtree rooted at op */

		acpi_ps_delete_parse_tree (op);

		return_VALUE (TRUE);
	}

	return_VALUE (FALSE);

#else
	return (FALSE);
#endif
}


/*******************************************************************************
 *
 * FUNCTION:    Acpi_ps_next_parse_state
 *
 * PARAMETERS:  Parser_state        - Current parser state object
 *
 * RETURN:      Status
 *
 * DESCRIPTION: Update the parser state based upon the return exception from
 *              the parser callback.
 *
 ******************************************************************************/

acpi_status
acpi_ps_next_parse_state (
	acpi_walk_state         *walk_state,
	acpi_parse_object       *op,
	acpi_status             callback_status)
{
	acpi_parse_state        *parser_state = &walk_state->parser_state;
	acpi_status             status = AE_CTRL_PENDING;


	ACPI_FUNCTION_TRACE_PTR ("Ps_next_parse_state", op);


	switch (callback_status) {
	case AE_CTRL_TERMINATE:

		/*
		 * A control method was terminated via a RETURN statement.
		 * The walk of this method is complete.
		 */
		parser_state->aml = parser_state->aml_end;
		status = AE_CTRL_TERMINATE;
		break;


	case AE_CTRL_BREAK:

		parser_state->aml = walk_state->aml_last_while;
		walk_state->control_state->common.value = FALSE;
		status = AE_CTRL_BREAK;
		break;

	case AE_CTRL_CONTINUE:


		parser_state->aml = walk_state->aml_last_while;
		status = AE_CTRL_CONTINUE;
		break;

	case AE_CTRL_PENDING:

		parser_state->aml = walk_state->aml_last_while;
		break;


	case AE_CTRL_TRUE:

		/*
		 * Predicate of an IF was true, and we are at the matching ELSE.
		 * Just close out this package
		 */
		parser_state->aml = acpi_ps_get_next_package_end (parser_state);
		break;