Re: [RFC PATCH] selftests/livepatch: only consider supported arches

[Joe Lawrence <joe.lawrence@redhat.com>]

On Fri, Jul 12, 2019 at 01:14:02PM -0400, Joe Lawrence wrote:
> Only run the livepatching self-tests on x86_64 and ppc64le arches.
> 
> Reported-by: Jiri Benc <jbenc@redhat.com>
> Signed-off-by: Joe Lawrence <joe.lawrence@redhat.com>
> ---
>  tools/testing/selftests/livepatch/Makefile | 13 +++++++++++++
>  1 file changed, 13 insertions(+)
> 
> diff --git a/tools/testing/selftests/livepatch/Makefile b/tools/testing/selftests/livepatch/Makefile
> index fd405402c3ff..9842fb473d42 100644
> --- a/tools/testing/selftests/livepatch/Makefile
> +++ b/tools/testing/selftests/livepatch/Makefile
> @@ -1,5 +1,16 @@
>  # SPDX-License-Identifier: GPL-2.0
>  
> +ARCH ?= $(shell uname -m 2>/dev/null || echo not)
> +
> +ifeq ($(ARCH),x86_64)
> +livepatch_supported := 1
> +endif
> +ifeq ($(ARCH),ppc64le)
> +livepatch_supported := 1
> +endif
> +
> +ifdef livepatch_supported
> +
>  TEST_PROGS_EXTENDED := functions.sh
>  TEST_PROGS := \
>  	test-livepatch.sh \
> @@ -7,3 +18,5 @@ TEST_PROGS := \
>  	test-shadow-vars.sh
>  
>  include ../lib.mk
> +
> +endif
> -- 
> 2.21.0
> 

Hi Shuah,

This was change was a quick and dirty fix to avoid inadvertent errors
reported by run_kselftest.sh on arches unsupported by livepatch.

Ideally we would check CONFIG_TEST_LIVEPATCH instead of the arches
directly:  This would allow distros to "turn off" this particular set of
selftests through the kernel configuration.  Also, setting 
CONFIG_TEST_LIVEPATCH=m determines whether supporting livepatch
self-test modules (in lib/livepatch) will be built.  Without it, these
self-test scripts are useless.

However, I didn't see that $(CONFIG_TEST_LIVEPATCH) was set when
invoking tools/testing/selftests/livepatch/Makefile.  I don't know how
tools/testing/selftests/vDSO/Makefile is using $(CONFIG_X86_32) but
perhaps that isn't working either.

Any suggestions?  Should we modify the test scripts themselves to deal
with a !CONFIG_TEST_LIVEPATCH environment?

Thanks,

-- Joe