ACPICA: Methods now implicitly return 0 in slack mode

Implemented an enhancement to the interpreter "slack mode". In the
absence of an explicit return or an implicitly returned object from
the last executed opcode, a control method will now implicitly
return an integer of value 0 for Microsoft compatibility.

http://www.acpica.org/bugzilla/show_bug.cgi?id=392

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

diff --git a/drivers/acpi/parser/psparse.c b/drivers/acpi/parser/psparse.c
index a8995ca..a4c4020 100644 (file)
--- a/drivers/acpi/parser/psparse.c
+++ b/drivers/acpi/parser/psparse.c
@@ -594,6 +594,30 @@ acpi_status acpi_ps_parse_aml(struct acpi_walk_state *walk_state)
                                 * The object is deleted
                                 */
                                if (!previous_walk_state->return_desc) {
+                                       /*
+                                        * In slack mode execution, if there is no return value
+                                        * we should implicitly return zero (0) as a default value.
+                                        */
+                                       if (acpi_gbl_enable_interpreter_slack &&
+                                           !previous_walk_state->
+                                           implicit_return_obj) {
+                                               previous_walk_state->
+                                                   implicit_return_obj =
+                                                   acpi_ut_create_internal_object
+                                                   (ACPI_TYPE_INTEGER);
+                                               if (!previous_walk_state->
+                                                   implicit_return_obj) {
+                                                       return_ACPI_STATUS
+                                                           (AE_NO_MEMORY);
+                                               }
+
+                                               previous_walk_state->
+                                                   implicit_return_obj->
+                                                   integer.value = 0;
+                                       }
+
+                                       /* Restart the calling control method */
+
                                        status =
                                            acpi_ds_restart_control_method
                                            (walk_state,