RFR: 8315716: RISC-V: implement ChaCha20 intrinsic

[Hamlin Li]

On Mon, 25 Sep 2023 12:19:22 GMT, Robbin Ehn <rehn at openjdk.org> wrote:

> Thanks, can you include what testing you have done in the PR description? (testing as in validating the code is correct)

added.

> src/hotspot/cpu/riscv/stubGenerator_riscv.cpp line 4343:
> 
>> 4341:     // in java level.
>> 4342:     __ li(avl, 16);
>> 4343:     __ vsetvli(length, avl, Assembler::e32, Assembler::m1, Assembler::ma, Assembler::ta);
> 
> Is this really correct.
> We have no uses of ma/ta before this since we need to make sure we never touch memory outside of the arrays.
> I don't think ma/ta will ever be correct when working on Java heap.
> 
> I would drop the last two argument and use the default of mu/tu as we do everywhere else.

I'm not quite sure, but modified as you suggested.

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PR Comment: https://git.openjdk.org/jdk/pull/15899#issuecomment-1733756083
PR Review Comment: https://git.openjdk.org/jdk/pull/15899#discussion_r1336204681