The asm-arm/unaligned.h includes linux/unaligned/access_ok.h
This file is unsafe to be used on ARM, since it does an unaligned memory
accesses which fails on ARM.
Lookin at Linux the basic difference seems to be the header
"include/asm-arm/unaligned.h". The Linux version of "unaligned.h"
does *not* include "access_ok.h" at all. It includes "le_byteshift.h"
and "be_byteshift.h" instead.