psparse.c

linux-2.6.15.6

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;
	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);

			/* Ensure proper cleanup */

			walk_state->parse_flags |= ACPI_PARSE_EXECUTE;

			/* 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;
			}
		}

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

				walk_state->method_desc->method.thread_count--;
			}

			acpi_ds_terminate_control_method(walk_state);
		}

		/* 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);
}