diff --git a/drivers/acpi/processor_idle.c b/drivers/acpi/processor_idle.c
index 6c6751b1405be5d7547a0e7f9010bc7dbaa82593..59fac8d794123d2e91f844c1c1ea22165b031f51 100644
--- a/drivers/acpi/processor_idle.c
+++ b/drivers/acpi/processor_idle.c
@@ -40,6 +40,14 @@
 #include <linux/sched.h>	/* need_resched() */
 #include <linux/latency.h>
 
+/*
+ * Include the apic definitions for x86 to have the APIC timer related defines
+ * available also for UP (on SMP it gets magically included via linux/smp.h).
+ */
+#ifdef CONFIG_X86
+#include <asm/apic.h>
+#endif
+
 #include <asm/io.h>
 #include <asm/uaccess.h>