[PATCH v4] crypto: riscv/poly1305 - import OpenSSL/CRYPTOGAMS implementation

[Andy Polyakov]

Hi,

> Next, I plan to validate this performance gain on actual RISC-V
> hardware.

I've rerun my benchmarks, the cycles-per-byte results quoted in the 
poly1305-riscv.pl commentary section, and it appears that my U74 results 
were off. I must have made wrong assumptions about clock frequency or I 
failed to note that the [shared] system was busy. Either way, U74 
delivers 1.8 cpb, be it the initial processor version or one with 
additional ISA capabilities such as Zbb, JH7100 vs. JH7110. For 
reference, the cpb is calculated by dividing the clock frequency by the 
measured MBps rate.

I also have vector implementation cooking. It's not ready to be 
released, because it doesn't yet scale with vlenb and works only on a 
256-bit vector unit. It achieves 1.3 cpb on Spacemit X60, 2.5x 
improvement over scalar code. Just in case, one can't expect the 
coefficient to be the same on other processors.

Cheers.