Index: head/sys/kern/link_elf.c
===================================================================
--- head/sys/kern/link_elf.c
+++ head/sys/kern/link_elf.c
@@ -51,6 +51,7 @@
 #include <sys/fcntl.h>
 #include <sys/vnode.h>
 #include <sys/linker.h>
+#include <sys/sysctl.h>
 
 #include <machine/elf.h>
 
@@ -389,6 +390,13 @@
 
 extern vm_offset_t __startkernel, __endkernel;
 
+static unsigned long kern_relbase = KERNBASE;
+
+SYSCTL_ULONG(_kern, OID_AUTO, base_address, CTLFLAG_RD,
+	SYSCTL_NULL_ULONG_PTR, KERNBASE, "Kernel base address");
+SYSCTL_ULONG(_kern, OID_AUTO, relbase_address, CTLFLAG_RD,
+	&kern_relbase, 0, "Kernel relocated base address");
+
 static void
 link_elf_init(void* arg)
 {
@@ -431,6 +439,7 @@
 #ifdef __powerpc__
 	linker_kernel_file->address = (caddr_t)__startkernel;
 	linker_kernel_file->size = (intptr_t)(__endkernel - __startkernel);
+	kern_relbase = (unsigned long)__startkernel;
 #else
 	linker_kernel_file->address += KERNBASE;
 	linker_kernel_file->size = -(intptr_t)linker_kernel_file->address;