[RFC] [Question] memset.S old code stuff

[Bradley Morgan]

On 4 August 2026 18:20:43 BST, Mark Rutland <mark.rutland at arm.com> wrote:
>On Tue, Aug 04, 2026 at 04:57:54PM +0100, Catalin Marinas wrote:
>> On Thu, Jul 23, 2026 at 12:17:15AM +0100, Bradley Morgan wrote:
>> > Hey folks, sorry for the crazy asm emails, I see that in memset.S in
>> > arch/arm64/lib/memset.S, the code is incredibly old code, like 2013
>old
>> > (heh).
>> > 
>> > I was wondering if I could say, adapt it from optimized-routines (same
>> > treatment as memcpy.S essentially.
>> 
>> I think Robin attempted until he realised the use of the Q registers in
>> the Cortex Strings library, mentioned here:
>>

I would say scalar port??

>> https://lore.kernel.org/all/cover.1571073960.git.robin.murphy@arm.com/
>
>We also subsequently looked at moving away from Cortex-strings entirely,
>e.g.
>
>  https://lore.kernel.org/linux-arm-kernel/20230314115030.347976-1-mark.rutland@arm.com/
>
>... but there were open questions on the semantics, and no clear path
>forwards at the time.
>
>Writing the code isn't the hard part. We need to get wider agreement on
>the semantics, test on a variety of platforms, etc.
>
>For now, I think it'd be best to leave as-is, since it's a time sink for
>reviewers.

Ack. Again, a scalar port is iffy, not 100%. 

That would require time.


>Mark.
>

Thanks!