ACPICA: Remove possibility of executing _REG methods twice

If a custom address space handler is installed by the host
before the "initialize operation regions" phase of the ACPICA
initialization, any _REG methods for that address space could
be executed twice. This change fixes the problem.
ACPICA BZ 427.

http://www.acpica.org/bugzilla/show_bug.cgi?id=427

Signed-off-by: Lin Ming <ming.m.lin@intel.com>
Signed-off-by: Bob Moore <robert.moore@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>

1 files changed, 59 insertions, 5 deletions

diff --git a/drivers/acpi/acpica/evregion.c b/drivers/acpi/acpica/evregion.c
index 98c7f9c62653..c9fa040725d4 100644
--- a/drivers/acpi/acpica/evregion.c
+++ b/drivers/acpi/acpica/evregion.c
@@ -51,6 +51,10 @@
 ACPI_MODULE_NAME("evregion")
 
 /* Local prototypes */
+static u8
+acpi_ev_has_default_handler(struct acpi_namespace_node *node,
+                            acpi_adr_space_type space_id);
+
 static acpi_status
 acpi_ev_reg_run(acpi_handle obj_handle,
                 u32 level, void *context, void **return_value);
@@ -142,6 +146,50 @@ acpi_status acpi_ev_install_region_handlers(void)
 
 /*******************************************************************************
  *
+ * FUNCTION:    acpi_ev_has_default_handler
+ *
+ * PARAMETERS:  Node                - Namespace node for the device
+ *              space_id            - The address space ID
+ *
+ * RETURN:      TRUE if default handler is installed, FALSE otherwise
+ *
+ * DESCRIPTION: Check if the default handler is installed for the requested
+ *              space ID.
+ *
+ ******************************************************************************/
+
+static u8
+acpi_ev_has_default_handler(struct acpi_namespace_node *node,
+                            acpi_adr_space_type space_id)
+{
+        union acpi_operand_object *obj_desc;
+        union acpi_operand_object *handler_obj;
+
+        /* Must have an existing internal object */
+
+        obj_desc = acpi_ns_get_attached_object(node);
+        if (obj_desc) {
+                handler_obj = obj_desc->device.handler;
+
+                /* Walk the linked list of handlers for this object */
+
+                while (handler_obj) {
+                        if (handler_obj->address_space.space_id == space_id) {
+                                if (handler_obj->address_space.handler_flags &
+                                    ACPI_ADDR_HANDLER_DEFAULT_INSTALLED) {
+                                        return (TRUE);
+                                }
+                        }
+
+                        handler_obj = handler_obj->address_space.next;
+                }
+        }
+
+        return (FALSE);
+}
+
+/*******************************************************************************
+ *
  * FUNCTION:    acpi_ev_initialize_op_regions
  *
  * PARAMETERS:  None
@@ -169,12 +217,18 @@ acpi_status acpi_ev_initialize_op_regions(void)
 
         for (i = 0; i < ACPI_NUM_DEFAULT_SPACES; i++) {
                 /*
-                 * TBD: Make sure handler is the DEFAULT handler, otherwise
-                 * _REG will have already been run.
+                 * Make sure the installed handler is the DEFAULT handler. If not the
+                 * default, the _REG methods will have already been run (when the
+                 * handler was installed)
                  */
-                status = acpi_ev_execute_reg_methods(acpi_gbl_root_node,
-                                                     acpi_gbl_default_address_spaces
-                                                     [i]);
+                if (acpi_ev_has_default_handler(acpi_gbl_root_node,
+                                                acpi_gbl_default_address_spaces
+                                                [i])) {
+                        status =
+                            acpi_ev_execute_reg_methods(acpi_gbl_root_node,
+                                                        acpi_gbl_default_address_spaces
+                                                        [i]);
+                }
         }
 
         (void)acpi_ut_release_mutex(ACPI_MTX_NAMESPACE);