Re: [PATCH v2 1/6] RISC-V: Add Zicclsm to cpufeature and hwprobe

Conor Dooley
2024-06-14T08:10:05Z

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On Thu, Jun 13, 2024 at 03:16:10PM -0400, Jesse Taube wrote:
> > Zicclsm Misaligned loads and stores to main memory regions with both
> > the cacheability and coherence PMAs must be supported.
> > Note:
> > This introduces a new extension name for this feature.
> > This requires misaligned support for all regular load and store
> > instructions (including scalar and vector) but not AMOs or other
> > specialized forms of memory access. Even though mandated, misaligned
> > loads and stores might execute extremely slowly. Standard software
> > distributions should assume their existence only for correctness,
> > not for performance.
>
> Detecing zicclsm allows the kernel to report if the
> hardware supports misaligned accesses even if support wasn't probed.
>
> This is useful for usermode to know if vector misaligned accesses are
> supported.
>
> Signed-off-by: Jesse Taube <jesse@rivosinc.com>

Reviewed-by: Conor Dooley <conor.dooley@microchip.com>

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