Index: sys/arm/include/vmparam.h
===================================================================
--- sys/arm/include/vmparam.h
+++ sys/arm/include/vmparam.h
@@ -68,7 +68,9 @@
  * The line between user space and kernel space
  * Mappings >= KERNEL_BASE are constant across all processes
  */
+#ifndef KERNBASE
 #define	KERNBASE		0xc0000000
+#endif
 
 /*
  * max number of non-contig chunks of physical RAM you can have
Index: sys/conf/options.arm
===================================================================
--- sys/conf/options.arm
+++ sys/conf/options.arm
@@ -28,6 +28,7 @@
 IPI_IRQ_END		opt_smp.h
 FREEBSD_BOOT_LOADER	opt_global.h
 IXP4XX_FLASH_SIZE	opt_global.h
+KERNBASE		opt_global.h
 KERNPHYSADDR		opt_global.h
 KERNVIRTADDR		opt_global.h
 LINUX_BOOT_ABI		opt_global.h