--- /dev/null
+#ifndef __SYSDEP_I386_BARRIER_H
+#define __SYSDEP_I386_BARRIER_H
+
+/* Copied from include/asm-i386 for use by userspace. i386 has the option
+ * of using mfence, but I'm just using this, which works everywhere, for now.
+ */
+#define mb() asm volatile("lock; addl $0,0(%esp)")
+
+#endif