[PATCH v4 0/4] selftests: Fix cpuid / vendor checking build issues

[Ilpo Järvinen]

This series first generalizes resctrl selftest non-contiguous CAT check
to not assume non-AMD vendor implies Intel. Second, it improves
selftests such that the use of __cpuid_count() does not lead into a
build failure (happens at least on ARM).

While ARM does not currently support resctrl features, there's an
ongoing work to enable resctrl support also for it on the kernel side.
In any case, a common header such as kselftest.h should have a proper
fallback in place for what it provides, thus it seems justified to fix
this common level problem on the common level rather than e.g.
disabling build for resctrl selftest for archs lacking resctrl support.

I've dropped reviewed and tested by tags from the last patch in v3 due
to major changes into the makefile logic. So it would be helpful if
Muhammad could retest with this version.

Acquiring ARCH in lib.mk will likely allow some cleanup into some
subdirectory makefiles but that is left as future work because this
series focuses in fixing cpuid/build.

v4:
- New patch to reorder x86 selftest makefile to avoid clobbering CFLAGS
  (would cause __cpuid_count() related build fail otherwise)

v3:
- Remove "empty" wording
- Also cast input parameters to void
- Initialize ARCH from uname -m if not set (this might allow cleaning
  up some other makefiles but that is left as future work)

v2:
- Removed RFC from the last patch & added Fixes and tags
- Fixed the error message's line splits
- Noted down the reason for void casts in the stub

Ilpo Järvinen (4):
  selftests/resctrl: Generalize non-contiguous CAT check
  selftests/resctrl: Always initialize ecx to avoid build warnings
  selftests/x86: don't clobber CFLAGS
  kselftest: Provide __cpuid_count() stub on non-x86 archs

 tools/testing/selftests/kselftest.h        |  6 +++++
 tools/testing/selftests/lib.mk             |  6 +++++
 tools/testing/selftests/resctrl/cat_test.c | 28 +++++++++++++---------
 tools/testing/selftests/x86/Makefile       |  4 +++-
 4 files changed, 32 insertions(+), 12 deletions(-)

-- 
2.39.2