[PATCH v2] riscv: Sync hwprobe definitions with Linux kernel

[Yangyu Chen]

> On 19 Sep 2025, at 20:33, Yao Zihong <zihong.plct@isrc.iscas.ac.cn> wrote:
> 
>> Add some new Linux RISC-V hwprobe definitions with the upstream linux
>> kernel. This is useful to support dl-hwcaps-subdirs for RISC-V and use
>> the new key RISCV_HWPROBE_KEY_MISALIGNED_SCALAR_PERF and
>> RISCV_HWPROBE_KEY_MISALIGNED_VECTOR_PERF to better determine multiple
>> implementations for IFUNC in the future.
> 
> Hi Yangyu,
> 
> Thanks for the patch.
> 
> I have a small WIP prototype for dl-hwcaps-subdirs on RISC-V, using
> rva20u64 as an initial example to explore a general approach that could
> extend to rva22u64/rva23u64.
> 
> Before I send an RFC, I’d like to check whether anyone is already working
> on a subdir implementation beyond this header sync; happy to align or
> hold off to avoid duplication.

I'm working on this, but I haven't finished it yet because I've
been busy with other daily tasks. If you've already completed this,
I'm glad to see your RFC patch.

Evan Green even proposed a patch [1] to support different architecture
levels, but there weren't any RVA profiles available at that time.
I think that moving to RVA profiles would be a great idea for now.

[1] https://inbox.sourceware.org/libc-alpha/20230428191200.3241429-1-evan@rivosinc.com/

Thanks,
Yangyu Chen

> 
> Best,
> Zihong