RFR: 8319716: RISC-V: Add SHA-2

[Robbin Ehn]

On Tue, 14 Nov 2023 08:12:57 GMT, Fei Yang <fyang at openjdk.org> wrote:

>> Hi, please consider.
>> 
>> Main author is @luhenry, I only fixed some minor things and tested it.
>> 
>> Such as:
>> test/hotspot/jtreg/compiler/intrinsics/sha/
>> test/jdk/java/security/MessageDigest/
>> test/jdk/jdk/security/
>> tier1
>> 
>> And still running some test.
>
> src/hotspot/cpu/riscv/vm_version_riscv.cpp line 160:
> 
>> 158:   }
>> 159: 
>> 160:   if (UseZvknha && UseZvkb) {
> 
> A simple question here: Does the existence of `Zvknhb` also means availability of `Zvknha`? Or should this be something like `if ((UseZvknha || UseZvknhb) && UseZvkb)`?

It seems like the correct answer is:
`• Zvknhb supports SHA-256 and SHA-512.`

I suggest we start with supporting Zvkn, which is:
Zvkned, Zvknhb, Zvkb, Zvkt
They require: Zve64x

If someone have a CPU lacking something we can revisit it.

(I *think* Zvknha is mainly for 32-bits, as it only require sew 32)

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PR Review Comment: https://git.openjdk.org/jdk/pull/16562#discussion_r1392369153