Add PowerPC crypto acceleration support for SHA2.
There is also a Power assembly version available for <= POWER 7,
but it was not ported.
I am getting ~10% improovement on sha256 and 40% improovement on sha512.
SHA512 7230ms 7240ms
SHA256 8700ms 8690ms
SHA512 4910ms 5430ms
SHA256 7860ms 7860ms
Author: Shawn Landden <email@example.com>
Date: Wed May 22 21:36:11 2019 -0300
Support for PowerPC's AES acceleration.
This generates the S-Boxes on the fly, and thus
is more resistant to side-channel attacks.
I get an approximentally 2-3X speed-up with vcrypto support.
However, I saw no benifits from additionally using assembly for
the block mode code, so it is disabled for adding unnecessary
complexity and code size.