[PATCH V2 0/4] selftests: Remove duplicate CPUID wrappers

[Reinette Chatre <reinette.chatre@intel.com>]

Changes since V1:
- V1: https://lore.kernel.org/lkml/cover.1644000145.git.reinette.chatre@intel.com/
- Change solution to not use __cpuid_count() from compiler's
  cpuid.h but instead use a local define of __cpuid_count()
  provided in kselftest.h to ensure tests continue working
  in all supported environments. (Shuah)
- Rewrite cover letter and changelogs to reflect new solution.

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.

Both gcc and clang/LLVM provide wrappers for CPUID but
the wrappers are not available in the minimal required
version of gcc, v3.2, that the selftests need to be used
in. __cpuid_count() was added to gcc in v4.4, which is ok for
kernels after v4.19 when the gcc minimal required version
was changed to v4.6.

Add a local define of __cpuid_count() to kselftest.h to
ensure that selftests can still work in environments with
older stable kernels (v4.9 and v4.14 that have the minimal
required version of gcc of v3.2). Update tests with private
CPUID wrappers to use the new macro.

Cc: Dave Hansen <dave.hansen@linux.intel.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 (4):
  selftests: Provide local define of __cpuid_count()
  selftests/vm/pkeys: Use provided __cpuid_count() macro
  selftests/x86/amx: Use provided __cpuid_count() macro
  selftests/x86/corrupt_xstate_header: Use provided __cpuid_count()
    macro

 tools/testing/selftests/kselftest.h           | 15 ++++++++++++
 tools/testing/selftests/vm/pkey-x86.h         | 21 ++--------------
 tools/testing/selftests/x86/amx.c             | 24 ++++++-------------
 .../selftests/x86/corrupt_xstate_header.c     | 16 ++-----------
 4 files changed, 26 insertions(+), 50 deletions(-)


base-commit: 09688c0166e76ce2fb85e86b9d99be8b0084cdf9
-- 
2.25.1