Here is how the kmem can be statically created:

 * see `man 4 kmem`

/dev/mem is typically created by:

 * mknod -m 660 /dev/mem c 1 1
 * chown root:kmem /dev/mem

The file kmem is the same as mem, except that the kernel virtual memory rather than physical memory is accessed. /dev/kmem is typically created by:

 * mknod -m 640 /dev/kmem c 1 2
 * chown root:kmem /dev/kmem

/dev/port is similar to mem, but the I/O ports are accessed. It is typically created by:

 * mknod -m 660 /dev/port c 1 4
 * chown root:mem /dev/port


Here is the description on the difference between kmem and mem.

http://lwn.net/Articles/147902/