Re: [PATCH 4/6] x86/cpu: Add platform ID to CPU info structure

[Dave Hansen]

On 2/8/26 13:37, Borislav Petkov wrote:
> On Fri, Feb 06, 2026 at 03:14:45PM -0800, Dave Hansen wrote:
>> diff -puN arch/x86/include/asm/processor.h~cpu-x86_stepping arch/x86/include/asm/processor.h
>> --- a/arch/x86/include/asm/processor.h~cpu-x86_stepping	2026-02-06 15:14:23.528790212 -0800
>> +++ b/arch/x86/include/asm/processor.h	2026-02-06 15:14:23.567791582 -0800
>> @@ -140,6 +140,8 @@ struct cpuinfo_x86 {
>>  		__u32		x86_vfm;
>>  	};
>>  	__u8			x86_stepping;
>> +	/* Intel-only. 3 bits: */
>> +	__u8			x86_platform_id;
> Can we call this something more generic so that we can do:
> 
> 	/* On Intel: platform ID
> 	/* On AMD: something else
> 
> so that we can use this on both vendors?
> 
> I don't have any usage in mind on AMD now but it might come in handy some day.

I'm racking my brain but having a hard time coming up with a good name
that would work for unknown future AMD things. ;)

Any suggestions? I'm not married to the name in any way.
I could prefix it with 'intel_' to make it more clear that someone _can_
do a union in the future, like we do with "Hardware defined CPU-type".

Or we could do:

	union {
		u8 intel_platform_id;
		u8 amd_unused;
	};

to make it utterly clear that it's free for use on AMD if someone goes
looking for AMD-usable space.