command "make ARCH=um" results in the following failure:

arch/um/sys-i386/built-in.o: In function `kmap_atomic_pfn':
(.text+0x2b50): undefined reference to `kmap_atomic_prot_pfn'
arch/um/sys-i386/built-in.o: In function `set_highmem_pages_init':
(.init.text+0xc3): undefined reference to `add_highpages_with_active_regions'

with gcc (GCC) 4.4.4 20100503 (Red Hat 4.4.4-2)

before this i have modified kernel as mentioned in this page:
http://www.mail-archive.com/user-mode-linux-devel@lists.sourceforge.net/msg06365.html