drivers/acpi/parser/psparse.c

/******************************************************************************
 *
 * 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.
 *
 ******************************************************************************/

acpi_status
acpi_ps_next_parse_state (
	struct acpi_walk_state          *walk_state,
	union acpi_parse_object         *op,
	acpi_status                     callback_status)
{
	struct 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;

#if 0
	case AE_CTRL_SKIP:

		parser_state->aml = parser_state->scope->parse_scope.pkg_end;
		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
		 */
		parser_state->aml = acpi_ps_get_next_package_end (parser_state);
		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.
		 */
		parser_state->aml = parser_state->scope->parse_scope.pkg_end;

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

		walk_state->control_state->common.value = FALSE;
		status = AE_CTRL_END;
		break;


	case AE_CTRL_TRANSFER:

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

		status = AE_CTRL_TRANSFER;
		walk_state->prev_op = op;
		walk_state->method_call_op = op;
		walk_state->method_call_node = (op->common.value.arg)->common.node;

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

		walk_state->return_used = acpi_ds_is_result_used (op, walk_state);
		break;


	default:

		status = callback_status;
		if ((callback_status & AE_CODE_MASK) == AE_CODE_CONTROL) {
			status = AE_OK;
		}
		break;
	}

	return_ACPI_STATUS (status);
}


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

acpi_status
acpi_ps_parse_aml (
	struct acpi_walk_state          *walk_state)
{
	acpi_status                     status;
	acpi_status                     terminate_status;
	struct acpi_thread_state        *thread;
	struct acpi_thread_state        *prev_walk_list = acpi_gbl_current_walk_list;
	struct acpi_walk_state          *previous_walk_state;


	ACPI_FUNCTION_TRACE ("ps_parse_aml");

	ACPI_DEBUG_PRINT ((ACPI_DB_PARSE,
		"Entered with walk_state=%p Aml=%p size=%X\n",
		walk_state, walk_state->parser_state.aml,
		walk_state->parser_state.aml_size));


	/* Create and initialize a new thread state */

	thread = acpi_ut_create_thread_state ();
	if (!thread) {
		return_ACPI_STATUS (AE_NO_MEMORY);
	}

	walk_state->thread = thread;
	acpi_ds_push_walk_state (walk_state, thread);

	/*
	 * This global allows the AML debugger to get a handle to the currently
	 * executing control method.
	 */
	acpi_gbl_current_walk_list = 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", walk_state));

	status = AE_OK;
	while (walk_state) {
		if (ACPI_SUCCESS (status)) {
			/*
			 * The parse_loop executes AML until the method terminates
			 * or calls another method.
			 */
			status = acpi_ps_parse_loop (walk_state);
		}

		ACPI_DEBUG_PRINT ((ACPI_DB_PARSE,
			"Completed one call to walk loop, %s State=%p\n",
			acpi_format_exception (status), walk_state));

		if (status == AE_CTRL_TRANSFER) {
			/*
			 * A method call was detected.
			 * Transfer control to the called control method
			 */
			status = acpi_ds_call_control_method (thread, walk_state, NULL);

			/*
			 * If the transfer to the new method method call worked, a new walk
			 * state was created -- get it
			 */
			walk_state = acpi_ds_get_current_walk_state (thread);
			continue;
		}
		else if (status == AE_CTRL_TERMINATE) {
			status = AE_OK;
		}
		else if ((status != AE_OK) && (walk_state->method_desc)) {
			ACPI_REPORT_METHOD_ERROR ("Method execution failed",
				walk_state->method_node, NULL, status);

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

			if ((status == AE_ALREADY_EXISTS) &&
				(!walk_state->method_desc->method.semaphore)) {
				/*
				 * This method is marked not_serialized, but it tried to create
				 * a named object, causing the second thread entrance to fail.
				 * We will workaround this by marking the method permanently
				 * as Serialized.
				 */
				walk_state->method_desc->method.method_flags |= AML_METHOD_SERIALIZED;
				walk_state->method_desc->method.concurrency = 1;
			}
		}

		if (walk_state->method_desc) {
			/* Decrement the thread count on the method parse tree */

			if (walk_state->method_desc->method.thread_count) {
				walk_state->method_desc->method.thread_count--;
			}
		}

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

		walk_state = acpi_ds_pop_walk_state (thread);

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

		acpi_ds_scope_stack_clear (walk_state);

		/*
		 * If we just returned from the execution of a control method,
		 * there's lots of cleanup to do
		 */
		if ((walk_state->parse_flags & ACPI_PARSE_MODE_MASK) == ACPI_PARSE_EXECUTE) {
			terminate_status = acpi_ds_terminate_control_method (walk_state);
			if (ACPI_FAILURE (terminate_status)) {
				ACPI_REPORT_ERROR ((
					"Could not terminate control method properly\n"));

				/* Ignore error and continue */
			}
		}

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

		acpi_ps_cleanup_scope (&walk_state->parser_state);

		previous_walk_state = walk_state;

		ACPI_DEBUG_PRINT ((ACPI_DB_PARSE,
			"return_value=%p, implicit_value=%p State=%p\n",
			walk_state->return_desc, walk_state->implicit_return_obj, walk_state));

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

		walk_state = acpi_ds_get_current_walk_state (thread);
		if (walk_state) {
			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 (!previous_walk_state->return_desc) {
					status = acpi_ds_restart_control_method (walk_state,
							 previous_walk_state->implicit_return_obj);
				}
				else {
					/*
					 * We have a valid return value, delete any implicit
					 * return value.
					 */
					acpi_ds_clear_implicit_return (previous_walk_state);

					status = acpi_ds_restart_control_method (walk_state,
							 previous_walk_state->return_desc);
				}
				if (ACPI_SUCCESS (status)) {
					walk_state->walk_type |= ACPI_WALK_METHOD_RESTART;
				}
			}
			else {
				/* On error, delete any return object */

				acpi_ut_remove_reference (previous_walk_state->return_desc);
			}
		}

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

				*(previous_walk_state->caller_return_desc) =
					previous_walk_state->return_desc;
			}
		}
		else {
			if (previous_walk_state->return_desc) {
				/* Caller doesn't want it, must delete it */

				acpi_ut_remove_reference (previous_walk_state->return_desc);
			}
			if (previous_walk_state->implicit_return_obj) {
				/* Caller doesn't want it, must delete it */

				acpi_ut_remove_reference (previous_walk_state->implicit_return_obj);
			}
		}

		acpi_ds_delete_walk_state (previous_walk_state);
	}

	/* Normal exit */

	acpi_ex_release_all_mutexes (thread);
	acpi_ut_delete_generic_state (ACPI_CAST_PTR (union acpi_generic_state, thread));
	acpi_gbl_current_walk_list = prev_walk_list;
	return_ACPI_STATUS (status);
}