[PATCH 3/3] ppc64le: Revert "powerpc: Optimized strcmp for power10" (CVE-2025-5702)

[Carlos O'Donell]

On 6/16/25 9:46 AM, Florian Weimer wrote:
> * Carlos O'Donell:
> 
>> This reverts commit 3367d8e180848030d1646f088759f02b8dfe0d6f
>>
>> Reason for revert: Power10 strcmp clobbers non-volatile vector
>> registers (Bug 33056)
>> ---
>>   sysdeps/powerpc/powerpc64/le/power10/strcmp.S | 233 ------------------
>>   sysdeps/powerpc/powerpc64/multiarch/Makefile  |   2 +-
>>   .../powerpc64/multiarch/ifunc-impl-list.c     |   4 -
>>   .../powerpc64/multiarch/strcmp-power10.S      |  26 --
>>   sysdeps/powerpc/powerpc64/multiarch/strcmp.c  |   4 -
>>   5 files changed, 1 insertion(+), 268 deletions(-)
>>   delete mode 100644 sysdeps/powerpc/powerpc64/le/power10/strcmp.S
>>   delete mode 100644 sysdeps/powerpc/powerpc64/multiarch/strcmp-power10.S
> 
> Should this one be reverted as well?

Yes, I did not include that commit as I removed the file entirely.

Let me expand it out for completeness.

Posted v2: https://inbox.sourceware.org/libc-alpha/20250616202221.1162240-1-carlos@redhat.com/T/#t

I double checked again for any missing commits that were not just
copyright year changes.

My intent was to capture a revert of the substantive changes in
reverse order.

> commit 90bcc8721ef82b7378d2b080141228660e862d56
> Author: Amrita H S <amritahs@linux.vnet.ibm.com>
> Date:   Fri Dec 15 11:48:17 2023 -0500
> 
>      powerpc: Fix performance issues of strcmp power10
>      
>      Current implementation of strcmp for power10 has
>      performance regression for multiple small sizes
>      and alignment combination.
>      
>      Most of these performance issues are fixed by this
>      patch. The compare loop is unrolled and page crosses
>      of unrolled loop is handled.
>      
>      Thanks to Paul E. Murphy for helping in fixing the
>      performance issues.
>      
>      Signed-off-by: Amrita H S <amritahs@linux.vnet.ibm.com>
>      Co-Authored-By: Paul E. Murphy <murphyp@linux.ibm.com>
>      Reviewed-by: Rajalakshmi Srinivasaraghavan <rajis@linux.ibm.com>
> 
> Thanks,
> Florian
> 


-- 
Cheers,
Carlos.