Re: [PATCH 1/3] v4 more sampling fun 1

speck for Greg KH <[email protected]> writes:
> On Mon, Mar 16, 2020 at 05:56:27PM -0700, speck for mark gross wrote:
>> From: mark gross <[email protected]>
>> Subject: [PATCH 1/3] x86/cpu: Add stepping field to x86_cpu_id structure
>> 
>> Intel uses the same family/model for several CPUs. Sometimes
>> the stepping must be checked to tell them apart.
>> 
>> Note that to keep this patch simple the new field has been added at the
>> end to avoid churn with all the pre-C99 initialized uses of this
>> structure. Such legacy usage will result in a "0" value for the stepping
>> field, hence X86_STEPPING_ANY is defined as "0".
>
> Are you sure about the "avoid churn" stuff?  Can't you just fix up the
> X86_FEATURE_MATCH() #define to do that?
>
> Also INTEL_CPU_FAM_ANY() already uses named identifiers, so you are ok
> with that usage.  How many other places is this "open coded" that would
> need to be fixed up.  Can't be more than 10-20, right?
>
>> --- a/include/linux/mod_devicetable.h
>> +++ b/include/linux/mod_devicetable.h
>> @@ -665,6 +665,7 @@ struct x86_cpu_id {
>>  	__u16 model;
>>  	__u16 feature;	/* bit index */
>>  	kernel_ulong_t driver_data;
>> +	__u16 stepping;
>>  };
>
> That just makes my eyes hurt, stepping really should be before
> driver_data.
>
> The macros should be fixed up anyway to use named identifiers, no time
> like the present :)
>
> And this, and the cleanups, can be done in public, like I thought we
> asked for before, right?

I have played with this already. That's a pretty amazing amount of
creative macro games all over the place and about 55+ files to cleanup.

Let me dust off the patches a bit and send them as reference to LKML.

Thanks,

        tglx