diff --git a/kernel/signal.c b/kernel/signal.c
index 887f2fe..f05f4c4 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -3102,6 +3102,12 @@
 out:
 	return error;
 }
+#ifdef CONFIG_GENERIC_SIGALTSTACK
+SYSCALL_DEFINE2(sigaltstack,const stack_t __user *,uss, stack_t __user *,uoss)
+{
+	return do_sigaltstack(uss, uoss, current_user_stack_pointer());
+}
+#endif
 
 int restore_altstack(const stack_t __user *uss)
 {