Index: kernel/generic/include/mm/as.h
===================================================================
--- kernel/generic/include/mm/as.h	(revision 8b65570552691ad6fa2a012cf20ea6571577cd46)
+++ kernel/generic/include/mm/as.h	(revision 8d6c1f139a0fd8ef52d018e1c68b0dcca5ec1ec9)
@@ -84,5 +84,9 @@
 #define USER_ADDRESS_SPACE_END      USER_ADDRESS_SPACE_END_ARCH
 
-#define USTACK_ADDRESS  USTACK_ADDRESS_ARCH
+#ifdef USTACK_ADDRESS_ARCH
+	#define USTACK_ADDRESS  USTACK_ADDRESS_ARCH
+#else
+	#define USTACK_ADDRESS  (USER_ADDRESS_SPACE_END - (STACK_SIZE - 1))
+#endif
 
 /** Kernel address space. */