According to Wikipedia, every Armv8 processor should support sha256 hashing instructions however /proc/cpuinfo doesn't list it. Could there be a failure to identify the feature by the kernel?
processor : 3
BogoMIPS : 108.00
Features : fp asimd evtstrm crc32 cpuid
CPU implementer : 0x41
CPU architecture: 8
CPU variant : 0x0
CPU part : 0xd08
CPU revision : 3