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path: root/drivers/acpi/namespace/nsxfeval.c
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Diffstat (limited to 'drivers/acpi/namespace/nsxfeval.c')
-rw-r--r--drivers/acpi/namespace/nsxfeval.c78
1 files changed, 78 insertions, 0 deletions
diff --git a/drivers/acpi/namespace/nsxfeval.c b/drivers/acpi/namespace/nsxfeval.c
index 38be5865d95..a085cc39c05 100644
--- a/drivers/acpi/namespace/nsxfeval.c
+++ b/drivers/acpi/namespace/nsxfeval.c
@@ -48,6 +48,10 @@
#define _COMPONENT ACPI_NAMESPACE
ACPI_MODULE_NAME("nsxfeval")
+
+/* Local prototypes */
+static void acpi_ns_resolve_references(struct acpi_evaluate_info *info);
+
#ifdef ACPI_FUTURE_USAGE
/*******************************************************************************
*
@@ -69,6 +73,7 @@ ACPI_MODULE_NAME("nsxfeval")
* be valid (non-null)
*
******************************************************************************/
+
acpi_status
acpi_evaluate_object_typed(acpi_handle handle,
acpi_string pathname,
@@ -283,6 +288,10 @@ acpi_evaluate_object(acpi_handle handle,
if (ACPI_SUCCESS(status)) {
+ /* Dereference Index and ref_of references */
+
+ acpi_ns_resolve_references(info);
+
/* Get the size of the returned object */
status =
@@ -352,6 +361,74 @@ ACPI_EXPORT_SYMBOL(acpi_evaluate_object)
/*******************************************************************************
*
+ * FUNCTION: acpi_ns_resolve_references
+ *
+ * PARAMETERS: Info - Evaluation info block
+ *
+ * RETURN: Info->return_object is replaced with the dereferenced object
+ *
+ * DESCRIPTION: Dereference certain reference objects. Called before an
+ * internal return object is converted to an external union acpi_object.
+ *
+ * Performs an automatic dereference of Index and ref_of reference objects.
+ * These reference objects are not supported by the union acpi_object, so this is a
+ * last resort effort to return something useful. Also, provides compatibility
+ * with other ACPI implementations.
+ *
+ * NOTE: does not handle references within returned package objects or nested
+ * references, but this support could be added later if found to be necessary.
+ *
+ ******************************************************************************/
+static void acpi_ns_resolve_references(struct acpi_evaluate_info *info)
+{
+ union acpi_operand_object *obj_desc = NULL;
+ struct acpi_namespace_node *node;
+
+ /* We are interested in reference objects only */
+
+ if (ACPI_GET_OBJECT_TYPE(info->return_object) !=
+ ACPI_TYPE_LOCAL_REFERENCE) {
+ return;
+ }
+
+ /*
+ * Two types of references are supported - those created by Index and
+ * ref_of operators. A name reference (AML_NAMEPATH_OP) can be converted
+ * to an union acpi_object, so it is not dereferenced here. A ddb_handle
+ * (AML_LOAD_OP) cannot be dereferenced, nor can it be converted to
+ * an union acpi_object.
+ */
+ switch (info->return_object->reference.class) {
+ case ACPI_REFCLASS_INDEX:
+
+ obj_desc = *(info->return_object->reference.where);
+ break;
+
+ case ACPI_REFCLASS_REFOF:
+
+ node = info->return_object->reference.object;
+ if (node) {
+ obj_desc = node->object;
+ }
+ break;
+
+ default:
+ return;
+ }
+
+ /* Replace the existing reference object */
+
+ if (obj_desc) {
+ acpi_ut_add_reference(obj_desc);
+ acpi_ut_remove_reference(info->return_object);
+ info->return_object = obj_desc;
+ }
+
+ return;
+}
+
+/*******************************************************************************
+ *
* FUNCTION: acpi_walk_namespace
*
* PARAMETERS: Type - acpi_object_type to search for
@@ -379,6 +456,7 @@ ACPI_EXPORT_SYMBOL(acpi_evaluate_object)
* function, etc.
*
******************************************************************************/
+
acpi_status
acpi_walk_namespace(acpi_object_type type,
acpi_handle start_object,