psparse.c

linux-2.6.15.6

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

/*
 * Copyright (C) 2000 - 2005, 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.
 */

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

#define _COMPONENT          ACPI_PARSER
ACPI_MODULE_NAME("psparse")

/*******************************************************************************
 *
 * 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:      Next AML opcode
 *
 * DESCRIPTION: Get next AML opcode (without incrementing AML pointer)
 *
 ******************************************************************************/

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

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

	if (opcode == AML_EXTENDED_OP_PREFIX) {
		/* Extended opcode, get the second opcode byte */

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

	return (opcode);
}

/*******************************************************************************
 *
 * FUNCTION:    acpi_ps_complete_this_op
 *
 * PARAMETERS:  walk_state      - Current State
 *              Op              - Op to complete
 *
 * RETURN:      Status
 *
 * DESCRIPTION: Perform any cleanup at the completion of an Op.
 *
 ******************************************************************************/

acpi_status
acpi_ps_complete_this_op(struct acpi_walk_state * walk_state,
			 union acpi_parse_object * op)
{
	union acpi_parse_object *prev;
	union acpi_parse_object *next;
	const struct acpi_opcode_info *parent_info;
	union 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_ACPI_STATUS(AE_OK);	/* OK for now */
	}

	/* 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)) {
		return_ACPI_STATUS(AE_OK);
	}

	/* Make sure that we only delete this subtree */

	if (op->common.parent) {
		prev = op->common.parent->common.value.arg;
		if (!prev) {
			/* Nothing more to do */

			goto cleanup;
		}

		/*
		 * 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->common.parent->common.
					    aml_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) {
				goto allocate_error;
			}
			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->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_BUFFER_OP)
			    || (op->common.parent->common.aml_opcode ==
				AML_PACKAGE_OP)
			    || (op->common.parent->common.aml_opcode ==
				AML_VAR_PACKAGE_OP)) {
				replacement_op =
				    acpi_ps_alloc_op(AML_INT_RETURN_VALUE_OP);
				if (!replacement_op) {
					goto allocate_error;
				}
			} else
			    if ((op->common.parent->common.aml_opcode ==
				 AML_NAME_OP)
				&& (walk_state->pass_number <=
				    ACPI_IMODE_LOAD_PASS2)) {
				if ((op->common.aml_opcode == AML_BUFFER_OP)
				    || (op->common.aml_opcode == AML_PACKAGE_OP)
				    || (op->common.aml_opcode ==
					AML_VAR_PACKAGE_OP)) {
					replacement_op =
					    acpi_ps_alloc_op(op->common.
							     aml_opcode);
					if (!replacement_op) {
						goto allocate_error;
					}

					replacement_op->named.data =
					    op->named.data;
					replacement_op->named.length =
					    op->named.length;
				}
			}
			break;

		default:

			replacement_op =
			    acpi_ps_alloc_op(AML_INT_RETURN_VALUE_OP);
			if (!replacement_op) {
				goto allocate_error;
			}
		}

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

		if (prev == op) {
			/* This op is the first in the list */

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

		/* Search the parent list */

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

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

      cleanup:

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

	acpi_ps_delete_parse_tree(op);
	return_ACPI_STATUS(AE_OK);

      allocate_error:

	/* Always delete the subtree, even on error */

	acpi_ps_delete_parse_tree(op);
	return_ACPI_STATUS(AE_NO_MEMORY);
}

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