What happend to __ucmpdi2 from David Woodhouse?
google has a few hits about stuff like this on 32bit powerpc with gcc 4.1.2:

ERROR: "__ucmpdi2" [drivers/net/s2io.ko] undefined!

using the drivers/net/s2io* files from 2.6.21 with 2.6.22-rc5 fixes the
compile.

25805dcf9d83098cf5492117ad2669cd14cc9b24 adds two u64 >>= 48 followed by
a switch statement (line 2889 and 6816).