Re: [PATCH v1 10/12] tools/x86/kcpuid: Update bitfields to x86-cpuid-db v2.0

[H. Peter Anvin]

On March 7, 2025 7:07:04 AM PST, "Ahmed S. Darwish" <darwi@xxxxxxxxxxxxx> wrote:
>On Thu, 06 Mar 2025, H. Peter Anvin wrote:
>>
>> Leaf 3h was not unique to Transmeta.
>>
>
>Thanks, I missed that Pentium III can provide leaf 0x3 as well.
>
>It seems that leaf 0x3's format differs between Intel and Transmeta.  On
>Intel, PSN is at ECX:EDX, while on Transmeta, the PSN is at EAX:EBX, and
>ECX:EDX on non-evaluation models provide the rest. [*]
>
>Unfortunately, so far, x86-cpuid-db does not support having a CPUID
>bitfield with different interpretations across vendors.
>
>Given that Linux force disables PSN at early boot, I'll just remove that
>leaf from the database — for now.  (Time wise, finishing the new
>linux/arch/x86/ CPUID data model for mainline submission is a much higher
>priority.)
>
>All the best,
>Ahmed
>
>[*] "Processor Recognition", Transmeta Corporation, 2002/05/07.

You can simply output the 128 bits as is. Some vendors will have zeroes in some of the fields, but it doesn't matter.