ACPICA: Implement deferred resolution of reference package elements

ACPICA commit 0c08790c56fdf0dc081ae869495a09d8c4230854

This change defers the resolution of package elements that
are named references until after the entire namespace has been
loaded from the definition block. This allows such references
to be in fact forward references for both module level code
and control methods.

Link: https://github.com/acpica/acpica/commit/0c08790c
Signed-off-by: Bob Moore <robert.moore@intel.com>
Signed-off-by: Lv Zheng <lv.zheng@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

1 files changed, 67 insertions, 331 deletions

diff --git a/drivers/acpi/acpica/dsobject.c b/drivers/acpi/acpica/dsobject.c
index 7df3152ed856..82448551781b 100644
--- a/drivers/acpi/acpica/dsobject.c
+++ b/drivers/acpi/acpica/dsobject.c
@@ -52,12 +52,6 @@
 #define _COMPONENT          ACPI_DISPATCHER
 ACPI_MODULE_NAME("dsobject")
 
-/* Local prototypes */
-static acpi_status
-acpi_ds_build_internal_object(struct acpi_walk_state *walk_state,
-			      union acpi_parse_object *op,
-			      union acpi_operand_object **obj_desc_ptr);
-
 #ifndef ACPI_NO_METHOD_EXECUTION
 /*******************************************************************************
  *
@@ -73,15 +67,13 @@ acpi_ds_build_internal_object(struct acpi_walk_state *walk_state,
  *              Simple objects are any objects other than a package object!
  *
  ******************************************************************************/
-
-static acpi_status
+acpi_status
 acpi_ds_build_internal_object(struct acpi_walk_state *walk_state,
 			      union acpi_parse_object *op,
 			      union acpi_operand_object **obj_desc_ptr)
 {
 	union acpi_operand_object *obj_desc;
 	acpi_status status;
-	acpi_object_type type;
 
 	ACPI_FUNCTION_TRACE(ds_build_internal_object);
 
@@ -89,140 +81,47 @@ acpi_ds_build_internal_object(struct acpi_walk_state *walk_state,
 	if (op->common.aml_opcode == AML_INT_NAMEPATH_OP) {
 		/*
 		 * This is a named object reference. If this name was
-		 * previously looked up in the namespace, it was stored in this op.
-		 * Otherwise, go ahead and look it up now
+		 * previously looked up in the namespace, it was stored in
+		 * this op. Otherwise, go ahead and look it up now
 		 */
 		if (!op->common.node) {
-			status = acpi_ns_lookup(walk_state->scope_info,
-						op->common.value.string,
-						ACPI_TYPE_ANY,
-						ACPI_IMODE_EXECUTE,
-						ACPI_NS_SEARCH_PARENT |
-						ACPI_NS_DONT_OPEN_SCOPE, NULL,
-						ACPI_CAST_INDIRECT_PTR(struct
-								       acpi_namespace_node,
-								       &(op->
-									 common.
-									 node)));
-			if (ACPI_FAILURE(status)) {
-
-				/* Check if we are resolving a named reference within a package */
-
-				if ((status == AE_NOT_FOUND)
-				    && (acpi_gbl_enable_interpreter_slack)
-				    &&
-				    ((op->common.parent->common.aml_opcode ==
-				      AML_PACKAGE_OP)
-				     || (op->common.parent->common.aml_opcode ==
-					 AML_VARIABLE_PACKAGE_OP))) {
-					/*
-					 * We didn't find the target and we are populating elements
-					 * of a package - ignore if slack enabled. Some ASL code
-					 * contains dangling invalid references in packages and
-					 * expects that no exception will be issued. Leave the
-					 * element as a null element. It cannot be used, but it
-					 * can be overwritten by subsequent ASL code - this is
-					 * typically the case.
-					 */
-					ACPI_DEBUG_PRINT((ACPI_DB_INFO,
-							  "Ignoring unresolved reference in package [%4.4s]\n",
-							  walk_state->
-							  scope_info->scope.
-							  node->name.ascii));
-
-					return_ACPI_STATUS(AE_OK);
-				} else {
-					ACPI_ERROR_NAMESPACE(op->common.value.
-							     string, status);
-				}
-
-				return_ACPI_STATUS(status);
-			}
-		}
-
-		/* Special object resolution for elements of a package */
-
-		if ((op->common.parent->common.aml_opcode == AML_PACKAGE_OP) ||
-		    (op->common.parent->common.aml_opcode ==
-		     AML_VARIABLE_PACKAGE_OP)) {
-			/*
-			 * Attempt to resolve the node to a value before we insert it into
-			 * the package. If this is a reference to a common data type,
-			 * resolve it immediately. According to the ACPI spec, package
-			 * elements can only be "data objects" or method references.
-			 * Attempt to resolve to an Integer, Buffer, String or Package.
-			 * If cannot, return the named reference (for things like Devices,
-			 * Methods, etc.) Buffer Fields and Fields will resolve to simple
-			 * objects (int/buf/str/pkg).
-			 *
-			 * NOTE: References to things like Devices, Methods, Mutexes, etc.
-			 * will remain as named references. This behavior is not described
-			 * in the ACPI spec, but it appears to be an oversight.
-			 */
-			obj_desc =
-			    ACPI_CAST_PTR(union acpi_operand_object,
-					  op->common.node);
-
-			status =
-			    acpi_ex_resolve_node_to_value(ACPI_CAST_INDIRECT_PTR
-							  (struct
-							   acpi_namespace_node,
-							   &obj_desc),
-							  walk_state);
-			if (ACPI_FAILURE(status)) {
-				return_ACPI_STATUS(status);
-			}
-
-			/*
-			 * Special handling for Alias objects. We need to setup the type
-			 * and the Op->Common.Node to point to the Alias target. Note,
-			 * Alias has at most one level of indirection internally.
-			 */
-			type = op->common.node->type;
-			if (type == ACPI_TYPE_LOCAL_ALIAS) {
-				type = obj_desc->common.type;
-				op->common.node =
-				    ACPI_CAST_PTR(struct acpi_namespace_node,
-						  op->common.node->object);
-			}
-
-			switch (type) {
-				/*
-				 * For these types, we need the actual node, not the subobject.
-				 * However, the subobject did not get an extra reference count above.
-				 *
-				 * TBD: should ex_resolve_node_to_value be changed to fix this?
-				 */
-			case ACPI_TYPE_DEVICE:
-			case ACPI_TYPE_THERMAL:
-
-				acpi_ut_add_reference(op->common.node->object);
 
-				/*lint -fallthrough */
-				/*
-				 * For these types, we need the actual node, not the subobject.
-				 * The subobject got an extra reference count in ex_resolve_node_to_value.
-				 */
-			case ACPI_TYPE_MUTEX:
-			case ACPI_TYPE_METHOD:
-			case ACPI_TYPE_POWER:
-			case ACPI_TYPE_PROCESSOR:
-			case ACPI_TYPE_EVENT:
-			case ACPI_TYPE_REGION:
-
-				/* We will create a reference object for these types below */
-				break;
+			/* Check if we are resolving a named reference within a package */
 
-			default:
+			if ((op->common.parent->common.aml_opcode ==
+			     AML_PACKAGE_OP)
+			    || (op->common.parent->common.aml_opcode ==
+				AML_VARIABLE_PACKAGE_OP)) {
 				/*
-				 * All other types - the node was resolved to an actual
-				 * object, we are done.
+				 * We won't resolve package elements here, we will do this
+				 * after all ACPI tables are loaded into the namespace. This
+				 * behavior supports both forward references to named objects
+				 * and external references to objects in other tables.
 				 */
-				goto exit;
+				goto create_new_object;
+			} else {
+				status = acpi_ns_lookup(walk_state->scope_info,
+							op->common.value.string,
+							ACPI_TYPE_ANY,
+							ACPI_IMODE_EXECUTE,
+							ACPI_NS_SEARCH_PARENT |
+							ACPI_NS_DONT_OPEN_SCOPE,
+							NULL,
+							ACPI_CAST_INDIRECT_PTR
+							(struct
+							 acpi_namespace_node,
+							 &(op->common.node)));
+				if (ACPI_FAILURE(status)) {
+					ACPI_ERROR_NAMESPACE(op->common.value.
+							     string, status);
+					return_ACPI_STATUS(status);
+				}
 			}
 		}
 	}
 
+create_new_object:
+
 	/* Create and init a new internal ACPI object */
 
 	obj_desc = acpi_ut_create_internal_object((acpi_ps_get_opcode_info
@@ -240,7 +139,27 @@ acpi_ds_build_internal_object(struct acpi_walk_state *walk_state,
 		return_ACPI_STATUS(status);
 	}
 
-exit:
+	/*
+	 * Handling for unresolved package reference elements.
+	 * These are elements that are namepaths.
+	 */
+	if ((op->common.parent->common.aml_opcode == AML_PACKAGE_OP) ||
+	    (op->common.parent->common.aml_opcode == AML_VARIABLE_PACKAGE_OP)) {
+		obj_desc->reference.resolved = TRUE;
+
+		if ((op->common.aml_opcode == AML_INT_NAMEPATH_OP) &&
+		    !obj_desc->reference.node) {
+			/*
+			 * Name was unresolved above.
+			 * Get the prefix node for later lookup
+			 */
+			obj_desc->reference.node =
+			    walk_state->scope_info->scope.node;
+			obj_desc->reference.aml = op->common.aml;
+			obj_desc->reference.resolved = FALSE;
+		}
+	}
+
 	*obj_desc_ptr = obj_desc;
 	return_ACPI_STATUS(status);
 }
@@ -351,200 +270,6 @@ acpi_ds_build_internal_buffer_obj(struct acpi_walk_state *walk_state,
 
 /*******************************************************************************
  *
- * FUNCTION:    acpi_ds_build_internal_package_obj
- *
- * PARAMETERS:  walk_state      - Current walk state
- *              op              - Parser object to be translated
- *              element_count   - Number of elements in the package - this is
- *                                the num_elements argument to Package()
- *              obj_desc_ptr    - Where the ACPI internal object is returned
- *
- * RETURN:      Status
- *
- * DESCRIPTION: Translate a parser Op package object to the equivalent
- *              namespace object
- *
- * NOTE: The number of elements in the package will be always be the num_elements
- * count, regardless of the number of elements in the package list. If
- * num_elements is smaller, only that many package list elements are used.
- * if num_elements is larger, the Package object is padded out with
- * objects of type Uninitialized (as per ACPI spec.)
- *
- * Even though the ASL compilers do not allow num_elements to be smaller
- * than the Package list length (for the fixed length package opcode), some
- * BIOS code modifies the AML on the fly to adjust the num_elements, and
- * this code compensates for that. This also provides compatibility with
- * other AML interpreters.
- *
- ******************************************************************************/
-
-acpi_status
-acpi_ds_build_internal_package_obj(struct acpi_walk_state *walk_state,
-				   union acpi_parse_object *op,
-				   u32 element_count,
-				   union acpi_operand_object **obj_desc_ptr)
-{
-	union acpi_parse_object *arg;
-	union acpi_parse_object *parent;
-	union acpi_operand_object *obj_desc = NULL;
-	acpi_status status = AE_OK;
-	u32 i;
-	u16 index;
-	u16 reference_count;
-
-	ACPI_FUNCTION_TRACE(ds_build_internal_package_obj);
-
-	/* Find the parent of a possibly nested package */
-
-	parent = op->common.parent;
-	while ((parent->common.aml_opcode == AML_PACKAGE_OP) ||
-	       (parent->common.aml_opcode == AML_VARIABLE_PACKAGE_OP)) {
-		parent = parent->common.parent;
-	}
-
-	/*
-	 * If we are evaluating a Named package object "Name (xxxx, Package)",
-	 * the package object already exists, otherwise it must be created.
-	 */
-	obj_desc = *obj_desc_ptr;
-	if (!obj_desc) {
-		obj_desc = acpi_ut_create_internal_object(ACPI_TYPE_PACKAGE);
-		*obj_desc_ptr = obj_desc;
-		if (!obj_desc) {
-			return_ACPI_STATUS(AE_NO_MEMORY);
-		}
-
-		obj_desc->package.node = parent->common.node;
-	}
-
-	/*
-	 * Allocate the element array (array of pointers to the individual
-	 * objects) based on the num_elements parameter. Add an extra pointer slot
-	 * so that the list is always null terminated.
-	 */
-	obj_desc->package.elements = ACPI_ALLOCATE_ZEROED(((acpi_size)
-							   element_count +
-							   1) * sizeof(void *));
-
-	if (!obj_desc->package.elements) {
-		acpi_ut_delete_object_desc(obj_desc);
-		return_ACPI_STATUS(AE_NO_MEMORY);
-	}
-
-	obj_desc->package.count = element_count;
-
-	/*
-	 * Initialize the elements of the package, up to the num_elements count.
-	 * Package is automatically padded with uninitialized (NULL) elements
-	 * if num_elements is greater than the package list length. Likewise,
-	 * Package is truncated if num_elements is less than the list length.
-	 */
-	arg = op->common.value.arg;
-	arg = arg->common.next;
-	for (i = 0; arg && (i < element_count); i++) {
-		if (arg->common.aml_opcode == AML_INT_RETURN_VALUE_OP) {
-			if (arg->common.node->type == ACPI_TYPE_METHOD) {
-				/*
-				 * A method reference "looks" to the parser to be a method
-				 * invocation, so we special case it here
-				 */
-				arg->common.aml_opcode = AML_INT_NAMEPATH_OP;
-				status =
-				    acpi_ds_build_internal_object(walk_state,
-								  arg,
-								  &obj_desc->
-								  package.
-								  elements[i]);
-			} else {
-				/* This package element is already built, just get it */
-
-				obj_desc->package.elements[i] =
-				    ACPI_CAST_PTR(union acpi_operand_object,
-						  arg->common.node);
-			}
-		} else {
-			status =
-			    acpi_ds_build_internal_object(walk_state, arg,
-							  &obj_desc->package.
-							  elements[i]);
-		}
-
-		if (*obj_desc_ptr) {
-
-			/* Existing package, get existing reference count */
-
-			reference_count =
-			    (*obj_desc_ptr)->common.reference_count;
-			if (reference_count > 1) {
-
-				/* Make new element ref count match original ref count */
-
-				for (index = 0; index < (reference_count - 1);
-				     index++) {
-					acpi_ut_add_reference((obj_desc->
-							       package.
-							       elements[i]));
-				}
-			}
-		}
-
-		arg = arg->common.next;
-	}
-
-	/* Check for match between num_elements and actual length of package_list */
-
-	if (arg) {
-		/*
-		 * num_elements was exhausted, but there are remaining elements in the
-		 * package_list. Truncate the package to num_elements.
-		 *
-		 * Note: technically, this is an error, from ACPI spec: "It is an error
-		 * for NumElements to be less than the number of elements in the
-		 * PackageList". However, we just print a message and
-		 * no exception is returned. This provides Windows compatibility. Some
-		 * BIOSs will alter the num_elements on the fly, creating this type
-		 * of ill-formed package object.
-		 */
-		while (arg) {
-			/*
-			 * We must delete any package elements that were created earlier
-			 * and are not going to be used because of the package truncation.
-			 */
-			if (arg->common.node) {
-				acpi_ut_remove_reference(ACPI_CAST_PTR
-							 (union
-							  acpi_operand_object,
-							  arg->common.node));
-				arg->common.node = NULL;
-			}
-
-			/* Find out how many elements there really are */
-
-			i++;
-			arg = arg->common.next;
-		}
-
-		ACPI_INFO(("Actual Package length (%u) is larger than "
-			   "NumElements field (%u), truncated",
-			   i, element_count));
-	} else if (i < element_count) {
-		/*
-		 * Arg list (elements) was exhausted, but we did not reach num_elements count.
-		 * Note: this is not an error, the package is padded out with NULLs.
-		 */
-		ACPI_DEBUG_PRINT((ACPI_DB_INFO,
-				  "Package List length (%u) smaller than NumElements "
-				  "count (%u), padded with null elements\n",
-				  i, element_count));
-	}
-
-	obj_desc->package.flags |= AOPOBJ_DATA_VALID;
-	op->common.node = ACPI_CAST_PTR(struct acpi_namespace_node, obj_desc);
-	return_ACPI_STATUS(status);
-}
-
-/*******************************************************************************
- *
  * FUNCTION:    acpi_ds_create_node
  *
  * PARAMETERS:  walk_state      - Current walk state
@@ -662,11 +387,20 @@ acpi_ds_init_object_from_op(struct acpi_walk_state *walk_state,
 
 	case ACPI_TYPE_PACKAGE:
 		/*
-		 * Defer evaluation of Package term_arg operand
+		 * Defer evaluation of Package term_arg operand and all
+		 * package elements. (01/2017): We defer the element
+		 * resolution to allow forward references from the package
+		 * in order to provide compatibility with other ACPI
+		 * implementations.
 		 */
 		obj_desc->package.node =
 		    ACPI_CAST_PTR(struct acpi_namespace_node,
 				  walk_state->operands[0]);
+
+		if (!op->named.data) {
+			return_ACPI_STATUS(AE_OK);
+		}
+
 		obj_desc->package.aml_start = op->named.data;
 		obj_desc->package.aml_length = op->named.length;
 		break;
@@ -818,9 +552,11 @@ acpi_ds_init_object_from_op(struct acpi_walk_state *walk_state,
 				/* Node was saved in Op */
 
 				obj_desc->reference.node = op->common.node;
-				obj_desc->reference.object =
-				    op->common.node->object;
 				obj_desc->reference.class = ACPI_REFCLASS_NAME;
+				if (op->common.node) {
+					obj_desc->reference.object =
+					    op->common.node->object;
+				}
 				break;
 
 			case AML_DEBUG_OP: