diff --git a/vm/callstack.c b/vm/callstack.c
index 271c7d9aa1..5c3ab0ea79 100644
--- a/vm/callstack.c
+++ b/vm/callstack.c
@@ -6,7 +6,7 @@ F_FASTCALL void save_callstack_bottom(F_STACK_FRAME *callstack_bottom)
 	stack_chain->callstack_bottom = callstack_bottom;
 }
 
-__attribute__((noinline)) void save_callstack_top(F_STACK_FRAME *callstack_top)
+F_FASTCALL __attribute__((noinline)) void save_callstack_top(F_STACK_FRAME *callstack_top)
 {
 	stack_chain->callstack_top = callstack_top;
 }