diff --git a/include/asm-x86/proto.h b/include/asm-x86/proto.h
index 1e17bcc..6c8b41b 100644
--- a/include/asm-x86/proto.h
+++ b/include/asm-x86/proto.h
@@ -20,7 +20,11 @@
 
 extern void check_efer(void);
 
+#ifdef CONFIG_X86_BIOS_REBOOT
 extern int reboot_force;
+#else
+static const int reboot_force = 0;
+#endif
 
 long do_arch_prctl(struct task_struct *task, int code, unsigned long addr);