v4.19.13 snapshot.
diff --git a/arch/um/include/asm/timex.h b/arch/um/include/asm/timex.h
new file mode 100644
index 0000000..e392a9a
--- /dev/null
+++ b/arch/um/include/asm/timex.h
@@ -0,0 +1,14 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __UM_TIMEX_H
+#define __UM_TIMEX_H
+
+typedef unsigned long cycles_t;
+
+static inline cycles_t get_cycles (void)
+{
+	return 0;
+}
+
+#define CLOCK_TICK_RATE (HZ)
+
+#endif