Re: [PATCH 0/3] selftests: Remove duplicate CPUID wrappers

[Shuah Khan <skhan@linuxfoundation.org>]

On 2/4/22 12:17 PM, Reinette Chatre wrote:
> A few tests that require running CPUID do so with a private
> implementation of a wrapper for CPUID. This duplication of
> the CPUID wrapper should be avoided but having one is also
> unnecessary because of the existence of a macro that can
> be used instead.
> 
> This series replaces private CPUID wrappers with calls
> to the __cpuid_count() macro from cpuid.h as made available
> by gcc and clang/llvm.
> 
> Cc: Dave Hansen <dave.hansen@linux.intel.com>
> Cc: Ram Pai <linuxram@us.ibm.com>
> Cc: Sandipan Das <sandipan@linux.ibm.com>
> Cc: Florian Weimer <fweimer@redhat.com>
> Cc: "Desnes A. Nunes do Rosario" <desnesn@linux.vnet.ibm.com>
> Cc: Ingo Molnar <mingo@kernel.org>
> Cc: Thiago Jung Bauermann <bauerman@linux.ibm.com>
> Cc: Michael Ellerman <mpe@ellerman.id.au>
> Cc: Michal Suchanek <msuchanek@suse.de>
> Cc: linux-mm@kvack.org
> Cc: Chang S. Bae <chang.seok.bae@intel.com>
> Cc: Borislav Petkov <bp@suse.de>
> Cc: Thomas Gleixner <tglx@linutronix.de>
> Cc: Ingo Molnar <mingo@redhat.com>
> Cc: "H. Peter Anvin" <hpa@zytor.com>
> Cc: x86@kernel.org
> Cc: Andy Lutomirski <luto@kernel.org>
> 
> Reinette Chatre (3):
>    selftests/vm/pkeys: Use existing __cpuid_count() macro
>    selftests/x86/amx: Use existing __cpuid_count() macro
>    selftests/x86/corrupt_xstate_header: Use existing __cpuid_count()
>      macro
> 
>   tools/testing/selftests/vm/pkey-x86.h         | 22 +++---------------
>   tools/testing/selftests/x86/amx.c             | 23 +++++--------------
>   .../selftests/x86/corrupt_xstate_header.c     | 17 ++------------
>   3 files changed, 11 insertions(+), 51 deletions(-)
> 

I am all for this cleanup. However, I am not finding __cpuid_count()
marco on my system with gcc:

gcc --version
gcc (Ubuntu 11.2.0-7ubuntu2) 11.2.0

My concern is regression on older gcc versions.

thanks,
-- Shuah