RFR: 8324304: RISC-V: add hw probe flags

[Fei Yang]

On Mon, 22 Jan 2024 15:10:53 GMT, Hamlin Li <mli at openjdk.org> wrote:

> Hi,
> Can you help to review this simple patch to add hw probe flags?
> Thanks!
> 
> Per https://github.com/torvalds/linux/blob/master/arch/riscv/include/uapi/asm/hwprobe.h, several extensions were already added in kernel code, we have several intrinsics or funtionalities depends on these extension, it's ready to add these hw probe flags already used in jdk into jdk code.

LGTM. Any test performed?
BTW: Seems that probe for option `UseZvkn` could also be added which consists of `Zvkned`, `Zvknhb`, `Zvkb` and `Zvkt`. I see these are also there in https://github.com/torvalds/linux/blob/master/arch/riscv/include/uapi/asm/hwprobe.h.

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Marked as reviewed by fyang (Reviewer).

PR Review: https://git.openjdk.org/jdk/pull/17519#pullrequestreview-1837835233