diff --git a/include/asm-ia64/ustack.h b/include/asm-ia64/ustack.h
new file mode 100644
index 0000000..da55c91
--- /dev/null
+++ b/include/asm-ia64/ustack.h
@@ -0,0 +1,16 @@
+#ifndef _ASM_IA64_USTACK_H
+#define _ASM_IA64_USTACK_H
+
+/*
+ * Constants for the user stack size
+ */
+
+#include <asm/page.h>
+
+/* The absolute hard limit for stack size is 1/2 of the mappable space in the region */
+#define MAX_USER_STACK_SIZE	(RGN_MAP_LIMIT/2)
+/* Make a default stack size of 2GB */
+#define DEFAULT_USER_STACK_SIZE	(1UL << 31)
+#define STACK_TOP		(0x6000000000000000UL + RGN_MAP_LIMIT)
+
+#endif /* _ASM_IA64_USTACK_H */