ACPICA: Enhance implicit return mechanism

For Windows compatibility, return an implicit integer of value
zero for methods that have no executable code. A default implicit
value of zero is provided for methods. Lin Ming.

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, 16 insertions, 0 deletions

diff --git a/drivers/acpi/parser/psxface.c b/drivers/acpi/parser/psxface.c
index 4985ce58c024..41b0c8c052a8 100644
--- a/drivers/acpi/parser/psxface.c
+++ b/drivers/acpi/parser/psxface.c
@@ -295,6 +295,22 @@ acpi_status acpi_ps_execute_method(struct acpi_evaluate_info *info)
                 goto cleanup;
         }
 
+        /*
+         * Start method evaluation with an implicit return of zero.
+         * This is done for Windows compatibility.
+         */
+        if (acpi_gbl_enable_interpreter_slack) {
+                walk_state->implicit_return_obj =
+                    acpi_ut_create_internal_object(ACPI_TYPE_INTEGER);
+                if (!walk_state->implicit_return_obj) {
+                        status = AE_NO_MEMORY;
+                        acpi_ds_delete_walk_state(walk_state);
+                        goto cleanup;
+                }
+
+                walk_state->implicit_return_obj->integer.value = 0;
+        }
+
         /* Parse the AML */
 
         status = acpi_ps_parse_aml(walk_state);