drivers/acpi/dispatcher/dsutils.c

/*******************************************************************************
 *
 * Module Name: dsutils - Dispatcher utilities
 *
 ******************************************************************************/

/*
 * 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.
 */


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

#define _COMPONENT          ACPI_DISPATCHER
	 ACPI_MODULE_NAME    ("dsutils")


/*******************************************************************************
 *
 * FUNCTION:    acpi_ds_clear_implicit_return
 *
 * PARAMETERS:  walk_state          - Current State
 *
 * RETURN:      None.
 *
 * DESCRIPTION: Clear and remove a reference on an implicit return value.  Used
 *              to delete "stale" return values (if enabled, the return value
 *              from every operator is saved at least momentarily, in case the
 *              parent method exits.)
 *
 ******************************************************************************/

void
acpi_ds_clear_implicit_return (
	struct acpi_walk_state          *walk_state)
{
	ACPI_FUNCTION_NAME ("ds_clear_implicit_return");


	/*
	 * Slack must be enabled for this feature
	 */
	if (!acpi_gbl_enable_interpreter_slack) {
		return;
	}

	if (walk_state->implicit_return_obj) {
		/*
		 * Delete any "stale" implicit return. However, in
		 * complex statements, the implicit return value can be
		 * bubbled up several levels.
		 */
		ACPI_DEBUG_PRINT ((ACPI_DB_DISPATCH,
			"Removing reference on stale implicit return obj %p\n",
			walk_state->implicit_return_obj));

		acpi_ut_remove_reference (walk_state->implicit_return_obj);
		walk_state->implicit_return_obj = NULL;
	}
}


#ifndef ACPI_NO_METHOD_EXECUTION

/*******************************************************************************
 *
 * FUNCTION:    acpi_ds_do_implicit_return
 *
 * PARAMETERS:  return_desc         - The return value
 *              walk_state          - Current State
 *              add_reference       - True if a reference should be added to the
 *                                    return object
 *
 * RETURN:      TRUE if implicit return enabled, FALSE otherwise
 *
 * DESCRIPTION: Implements the optional "implicit return".  We save the result
 *              of every ASL operator and control method invocation in case the
 *              parent method exit.  Before storing a new return value, we
 *              delete the previous return value.
 *
 ******************************************************************************/

u8
acpi_ds_do_implicit_return (
	union acpi_operand_object       *return_desc,
	struct acpi_walk_state          *walk_state,
	u8                              add_reference)
{
	ACPI_FUNCTION_NAME ("ds_do_implicit_return");


	/*
	 * Slack must be enabled for this feature, and we must
	 * have a valid return object
	 */
	if ((!acpi_gbl_enable_interpreter_slack) ||
		(!return_desc)) {
		return (FALSE);
	}

	ACPI_DEBUG_PRINT ((ACPI_DB_DISPATCH,
			"Result %p will be implicitly returned; Prev=%p\n",
			return_desc,
			walk_state->implicit_return_obj));

	/*
	 * Delete any "stale" implicit return value first. However, in
	 * complex statements, the implicit return value can be
	 * bubbled up several levels, so we don't clear the value if it
	 * is the same as the return_desc.
	 */
	if (walk_state->implicit_return_obj) {
		if (walk_state->implicit_return_obj == return_desc) {
			return (TRUE);
		}
		acpi_ds_clear_implicit_return (walk_state);
	}

	/* Save the implicit return value, add a reference if requested */

	walk_state->implicit_return_obj = return_desc;
	if (add_reference) {
		acpi_ut_add_reference (return_desc);
	}

	return (TRUE);
}


/*******************************************************************************
 *
 * FUNCTION:    acpi_ds_is_result_used
 *
 * PARAMETERS:  Op                  - Current Op
 *              walk_state          - Current State
 *
 * RETURN:      TRUE if result is used, FALSE otherwise
 *
 * DESCRIPTION: Check if a result object will be used by the parent
 *
 ******************************************************************************/

u8
acpi_ds_is_result_used (
	union acpi_parse_object         *op,
	struct acpi_walk_state          *walk_state)
{
	const struct acpi_opcode_info   *parent_info;

	ACPI_FUNCTION_TRACE_PTR ("ds_is_result_used", op);


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

	if (!op) {
		ACPI_DEBUG_PRINT ((ACPI_DB_ERROR, "Null Op\n"));
		return_VALUE (TRUE);
	}

	/*
	 * We know that this operator is not a
	 * Return() operator (would not come here.) The following code is the
	 * optional support for a so-called "implicit return". Some AML code
	 * assumes that the last value of the method is "implicitly" returned
	 * to the caller. Just save the last result as the return value.
	 * NOTE: this is optional because the ASL language does not actually
	 * support this behavior.
	 */
	acpi_ds_do_implicit_return (walk_state->result_obj, walk_state, TRUE);

	/*
	 * Now determine if the parent will use the result
	 *
	 * If there is no parent, or the parent is a scope_op, we are executing
	 * at the method level. An executing method typically has no parent,
	 * since each method is parsed separately.  A method invoked externally
	 * via execute_control_method has a scope_op as the parent.
	 */
	if ((!op->common.parent) ||
		(op->common.parent->common.aml_opcode == AML_SCOPE_OP)) {
		/* No parent, the return value cannot possibly be used */

		ACPI_DEBUG_PRINT ((ACPI_DB_DISPATCH, "At Method level, result of [%s] not used\n",
				acpi_ps_get_opcode_name (op->common.aml_opcode)));
		return_VALUE (FALSE);
	}

	/* Get info on the parent. The root_op is AML_SCOPE */

	parent_info = acpi_ps_get_opcode_info (op->common.parent->common.aml_opcode);
	if (parent_info->class == AML_CLASS_UNKNOWN) {
		ACPI_DEBUG_PRINT ((ACPI_DB_ERROR, "Unknown parent opcode. Op=%p\n", op));
		return_VALUE (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 (parent_info->class) {
	case AML_CLASS_CONTROL:

		switch (op->common.parent->common.aml_opcode) {
		case AML_RETURN_OP:

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

			goto result_used;

		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 == ACPI_CONTROL_PREDICATE_EXECUTING) &&
				(walk_state->control_state->control.predicate_op == op)) {
				goto result_used;
			}
			break;

		default:
			/* Ignore other control opcodes */
			break;
		}

		/* The general control opcode returns no result */

		goto result_not_used;


	case AML_CLASS_CREATE:

		/*
		 * These opcodes allow term_arg(s) as operands and therefore
		 * the operands can be method calls.  The result is used.
		 */
		goto result_used;


	case AML_CLASS_NAMED_OBJECT:

		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_PACKAGE_OP)     ||
			(op->common.parent->common.aml_opcode == AML_VAR_PACKAGE_OP) ||
			(op->common.parent->common.aml_opcode == AML_BUFFER_OP)      ||
			(op->common.parent->common.aml_opcode == AML_INT_EVAL_SUBTREE_OP)) {
			/*
			 * These opcodes allow term_arg(s) as operands and therefore
			 * the operands can be method calls.  The result is used.
			 */
			goto result_used;
		}

		goto result_not_used;


	default:

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


result_used:
	ACPI_DEBUG_PRINT ((ACPI_DB_DISPATCH, "Result of [%s] used by Parent [%s] Op=%p\n",
			acpi_ps_get_opcode_name (op->common.aml_opcode),
			acpi_ps_get_opcode_name (op->common.parent->common.aml_opcode), op));

	return_VALUE (TRUE);


result_not_used:
	ACPI_DEBUG_PRINT ((ACPI_DB_DISPATCH, "Result of [%s] not used by Parent [%s] Op=%p\n",
			acpi_ps_get_opcode_name (op->common.aml_opcode),
			acpi_ps_get_opcode_name (op->common.parent->common.aml_opcode), op));

	return_VALUE (FALSE);
}


/*******************************************************************************
 *
 * FUNCTION:    acpi_ds_delete_result_if_not_used
 *
 * PARAMETERS:  Op              - Current parse Op
 *              result_obj      - Result of the operation
 *              walk_state      - Current 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 (
	union acpi_parse_object         *op,
	union acpi_operand_object       *result_obj,
	struct acpi_walk_state          *walk_state)
{
	union acpi_operand_object       *obj_desc;
	acpi_status                     status;


	ACPI_FUNCTION_TRACE_PTR ("ds_delete_result_if_not_used", result_obj);


	if (!op) {
		ACPI_DEBUG_PRINT ((ACPI_DB_ERROR, "Null Op\n"));
		return_VOID;
	}

	if (!result_obj) {
		return_VOID;
	}

	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_ut_remove_reference (result_obj);
		}
	}

	return_VOID;
}


/*******************************************************************************
 *
 * FUNCTION:    acpi_ds_resolve_operands
 *
 * PARAMETERS:  walk_state          - Current walk state with operands on stack
 *
 * RETURN:      Status
 *
 * DESCRIPTION: Resolve all operands to their values.  Used to prepare
 *              arguments to a control method invocation (a call from one
 *              method to another.)
 *
 ******************************************************************************/

acpi_status
acpi_ds_resolve_operands (
	struct acpi_walk_state          *walk_state)
{
	u32                             i;
	acpi_status                     status = AE_OK;


	ACPI_FUNCTION_TRACE_PTR ("ds_resolve_operands", walk_state);


	/*
	 * Attempt to resolve each of the valid operands
	 * Method arguments are passed by reference, not by value.  This means
	 * that the actual objects are passed, not copies of the objects.
	 */
	for (i = 0; i < walk_state->num_operands; i++) {
		status = acpi_ex_resolve_to_value (&walk_state->operands[i], walk_state);
		if (ACPI_FAILURE (status)) {
			break;
		}
	}

	return_ACPI_STATUS (status);
}


/*******************************************************************************
 *
 * FUNCTION:    acpi_ds_clear_operands
 *
 * PARAMETERS:  walk_state          - Current walk state with operands on stack
 *
 * RETURN:      None
 *
 * DESCRIPTION: Clear all operands on the current walk state operand stack.
 *
 ******************************************************************************/

void
acpi_ds_clear_operands (
	struct acpi_walk_state          *walk_state)
{
	u32                             i;


	ACPI_FUNCTION_TRACE_PTR ("ds_clear_operands", walk_state);


	/* Remove a reference on each operand on the stack */

	for (i = 0; i < walk_state->num_operands; i++) {
		/*
		 * Remove a reference to all operands, including both
		 * "Arguments" and "Targets".
		 */
		acpi_ut_remove_reference (walk_state->operands[i]);
		walk_state->operands[i] = NULL;
	}

	walk_state->num_operands = 0;
	return_VOID;
}
#endif


/*******************************************************************************
 *
 * FUNCTION:    acpi_ds_create_operand
 *
 * PARAMETERS:  walk_state      - Current walk state
 *              Arg             - Parse object for the argument
 *              arg_index       - Which argument (zero based)
 *
 * 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 (
	struct acpi_walk_state          *walk_state,
	union acpi_parse_object         *arg,
	u32                             arg_index)
{
	acpi_status                     status = AE_OK;
	char                            *name_string;
	u32                             name_length;
	union acpi_operand_object       *obj_desc;
	union acpi_parse_object         *parent_op;
	u16                             opcode;
	acpi_interpreter_mode           interpreter_mode;
	const struct acpi_opcode_info   *op_info;


	ACPI_FUNCTION_TRACE_PTR ("ds_create_operand", arg);


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

	if ((arg->common.aml_opcode == AML_INT_NAMEPATH_OP) &&
		(arg->common.value.string)) {
		ACPI_DEBUG_PRINT ((ACPI_DB_DISPATCH, "Getting a name: Arg=%p\n", arg));

		/* Get the entire name string from the AML stream */

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

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

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

		/*
		 * Special handling for buffer_field declarations. This is a deferred
		 * opcode that unfortunately defines the field name as the last
		 * parameter instead of the first.  We get here when we are performing
		 * the deferred execution, so the actual name of the field is already
		 * in the namespace.  We don't want to attempt to look it up again
		 * because we may be executing in a different scope than where the
		 * actual opcode exists.
		 */
		if ((walk_state->deferred_node) &&
			(walk_state->deferred_node->type == ACPI_TYPE_BUFFER_FIELD) &&
			(arg_index != 0)) {
			obj_desc = ACPI_CAST_PTR (union acpi_operand_object, walk_state->deferred_node);
			status = AE_OK;
		}
		else    /* All other opcodes */ {
			/*
			 * 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->common.parent;
			op_info = acpi_ps_get_opcode_info (parent_op->common.aml_opcode);
			if ((op_info->flags & AML_NSNODE) &&
				(parent_op->common.aml_opcode != AML_INT_METHODCALL_OP) &&
				(parent_op->common.aml_opcode != AML_REGION_OP) &&
				(parent_op->common.aml_opcode != AML_INT_NAMEPATH_OP)) {
				/* Enter name into namespace if not found */

				interpreter_mode = ACPI_IMODE_LOAD_PASS2;
			}
			else {
				/* Return a failure if name not found */

				interpreter_mode = ACPI_IMODE_EXECUTE;
			}

			status = acpi_ns_lookup (walk_state->scope_info, name_string,
					 ACPI_TYPE_ANY, interpreter_mode,
					 ACPI_NS_SEARCH_PARENT | ACPI_NS_DONT_OPEN_SCOPE,
					 walk_state,
					 ACPI_CAST_INDIRECT_PTR (struct acpi_namespace_node, &obj_desc));
			/*
			 * 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->common.aml_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_CAST_PTR (union 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;
				}
			}

			if (ACPI_FAILURE (status)) {
				ACPI_REPORT_NSERROR (name_string, status);
			}
		}

		/* Free the namestring created above */

		ACPI_MEM_FREE (name_string);

		/* Check status from the lookup */

		if (ACPI_FAILURE (status)) {
			return_ACPI_STATUS (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_ACPI_STATUS (status);
		}
		ACPI_DEBUGGER_EXEC (acpi_db_display_argument_object (obj_desc, walk_state));
	}
	else {
		/* Check for null name case */

		if (arg->common.aml_opcode == AML_INT_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 a Zero Constant for a
			 * placeholder.  (Store to a constant is a Noop.)
			 */
			opcode = AML_ZERO_OP;       /* Has no arguments! */

			ACPI_DEBUG_PRINT ((ACPI_DB_DISPATCH, "Null namepath: Arg=%p\n", arg));
		}
		else {
			opcode = arg->common.aml_opcode;
		}

		/* Get the object type of the argument */

		op_info = acpi_ps_get_opcode_info (opcode);
		if (op_info->object_type == ACPI_TYPE_INVALID) {
			return_ACPI_STATUS (AE_NOT_IMPLEMENTED);
		}

		if (op_info->flags & AML_HAS_RETVAL) {
			ACPI_DEBUG_PRINT ((ACPI_DB_DISPATCH,
				"Argument previously created, already stacked \n"));

			ACPI_DEBUGGER_EXEC (acpi_db_display_argument_object (
				walk_state->operands [walk_state->num_operands - 1], walk_state));

			/*
			 * Use value that was already previously returned
			 * by the evaluation of this argument
			 */
			status = acpi_ds_result_pop_from_bottom (&obj_desc, walk_state);
			if (ACPI_FAILURE (status)) {
				/*
				 * Only error is underflow, and this indicates
				 * a missing or null operand!
				 */
				ACPI_DEBUG_PRINT ((ACPI_DB_ERROR, "Missing or null operand, %s\n",
					acpi_format_exception (status)));
				return_ACPI_STATUS (status);
			}
		}
		else {
			/* Create an ACPI_INTERNAL_OBJECT for the argument */

			obj_desc = acpi_ut_create_internal_object (op_info->object_type);
			if (!obj_desc) {
				return_ACPI_STATUS (AE_NO_MEMORY);
			}

			/* Initialize the new object */

			status = acpi_ds_init_object_from_op (walk_state, arg,
					 opcode, &obj_desc);
			if (ACPI_FAILURE (status)) {
				acpi_ut_delete_object_desc (obj_desc);
				return_ACPI_STATUS (status);
			}
		}

		/* Put the operand object on the object stack */

		status = acpi_ds_obj_stack_push (obj_desc, walk_state);
		if (ACPI_FAILURE (status)) {
			return_ACPI_STATUS (status);
		}

		ACPI_DEBUGGER_EXEC (acpi_db_display_argument_object (obj_desc, walk_state));
	}

	return_ACPI_STATUS (AE_OK);
}


/*******************************************************************************
 *
 * FUNCTION:    acpi_ds_create_operands
 *
 * PARAMETERS:  walk_state          - Current state
 *              first_arg           - First argument of a parser argument tree
 *
 * RETURN:      Status
 *
 * DESCRIPTION: Convert an operator's arguments from a parse tree format to
 *              namespace objects and place those argument object on the object
 *              stack in preparation for evaluation by the interpreter.
 *
 ******************************************************************************/

acpi_status
acpi_ds_create_operands (
	struct acpi_walk_state          *walk_state,
	union acpi_parse_object         *first_arg)
{
	acpi_status                     status = AE_OK;
	union acpi_parse_object         *arg;
	u32                             arg_count = 0;


	ACPI_FUNCTION_TRACE_PTR ("ds_create_operands", first_arg);


	/* For all arguments in the list... */

	arg = first_arg;
	while (arg) {
		status = acpi_ds_create_operand (walk_state, arg, arg_count);
		if (ACPI_FAILURE (status)) {
			goto cleanup;
		}

		ACPI_DEBUG_PRINT ((ACPI_DB_DISPATCH, "Arg #%d (%p) done, Arg1=%p\n",
			arg_count, arg, first_arg));

		/* Move on to next argument, if any */

		arg = arg->common.next;
		arg_count++;
	}

	return_ACPI_STATUS (status);


cleanup:
	/*
	 * We must undo everything done above; meaning that we must
	 * pop everything off of the operand stack and delete those
	 * objects
	 */
	(void) acpi_ds_obj_stack_pop_and_delete (arg_count, walk_state);

	ACPI_DEBUG_PRINT ((ACPI_DB_ERROR, "While creating Arg %d - %s\n",
		(arg_count + 1), acpi_format_exception (status)));
	return_ACPI_STATUS (status);
}