Re: perf usage of arch/arm64/include/asm/cputype.h

[Leo Yan <leo.yan@arm.com>]

On Wed, Jun 18, 2025 at 07:51:03PM +0800, Yicong Yang wrote:

[...]

> >> Directly including the kernel header introduces the very fragility that
> >> having a copy was intended to avoid. NAK to that.
> > 
> > My suggestion is not to include the kernel header, nor to modify the
> > copy header. :)
> > 
> > Instead, I suggested creating a new header within the perf tool (under
> > perf's arm64 folder) and then include the copy header in tools:
> > 
> >   tools/arch/arm64/include/asm/cputype.h
> > 
> 
> sorry for the misunderstood.:(
> in this way we still have the divergency in the long term and as a workaround
> this works same if we partly update the tools/arch/arm64/include/asm/cputype.h
> with only necessary MIDR updates and keep is_midr_in_range_list() unchanged.

Yes. So Mark's suggestion is reasonable that we can do refactoring first
to avoid syncing header.

[...]

> > @Yicong, could you confirm if you proceed to refactor the MIDR? thanks!
> 
> please feel free to take this over.

Thanks a lot for confirmation!  And thanks for working on the reported
issue.

> > Just note, I searched tools folder and found kselftest also uses the
> > cputype.h header. The refactoring should not break the files below.
> > 
> 
> they shouldn't affected. I did a kselftest build test with my latest patch
> and they were not affected.

I expect tools/arch/arm64/include/asm/cputype.h will be removed, and
a generated header (something like sys-midr.h) for MIDR refactoring.
If this is true, then we need to take care kselftest.

Thanks,
Leo