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From:   Anders Roxell <anders.roxell@linaro.org>
Date:   Mon, 11 Jul 2022 14:13:44 +0200
Message-ID: <CADYN=9JncW4XKk8zVAuiux4R+FF2Z=LhBh--ajUqyGMC5yyxLQ@mail.gmail.com>
Subject: Re: [PATCH 0/4] Fix kselftest build with sub-directory
To:     Shuah Khan <skhan@linuxfoundation.org>
Cc:     Guillaume Tucker <guillaume.tucker@collabora.com>,
        Masahiro Yamada <masahiroy@kernel.org>,
        Michal Marek <michal.lkml@markovi.net>,
        Nick Desaulniers <ndesaulniers@google.com>,
        Shuah Khan <shuah@kernel.org>,
        Kees Cook <keescook@chromium.org>,
        Naresh Kamboju <naresh.kamboju@linaro.org>,
        kernel@collabora.com, linux-kbuild@vger.kernel.org,
        linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org
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On Fri, 8 Jul 2022 at 19:14, Shuah Khan <skhan@linuxfoundation.org> wrote:
>
> On 7/8/22 10:23 AM, Guillaume Tucker wrote:
> > Earlier attempts to get "make O=build kselftest-all" to work were
> > not successful as they made undesirable changes to some functions
> > in the top-level Makefile.  This series takes a different
> > approach by removing the root cause of the problem within
> > kselftest, which is when the sub-Makefile tries to install kernel
> > headers "backwards" by calling make with the top-level Makefile.
> > The actual issue comes from the fact that $(srctree) is ".." when
> > building in a sub-directory with "O=build" which then obviously
> > makes "-C $(top_srcdir)" point outside of the real source tree.
> >
> > With this series, the generic kselftest targets work as expected
> > from the top level with or without a build directory e.g.:
> >
> >    $ make kselftest-all
> >
> >    $ make O=build kselftest-all
> >
> > Then in order to build using the sub-Makefile explicitly, the
> > headers have to be installed first.  This is arguably a valid
> > requirement to have when building a tool from a sub-Makefile.
> > For example, "make -C tools/testing/nvdimm/" fails in a similar
> > way until <asm/rwonce.h> has been generated by a kernel build.
> >
> > Guillaume Tucker (4):
> >    selftests: drop khdr make target
> >    selftests: stop using KSFT_KHDR_INSTALL
> >    selftests: drop KSFT_KHDR_INSTALL make target
> >    Makefile: add headers_install to kselftest targets
> >
>
> This takes us to back to the state before b2d35fa5fc80 added
> khdr support. I reluctantly agreed to the change and it has
> proven to be a problematic change. I would rather have had the
> dependency stated that headers should be installed prior to
> building tests - test build depends on kernel build anyway and
> having dependency on headers having build isn't a huge deal.

I agree that it's not a huge deal.

>
> So I am in favor of getting rid of khdr support. However, this
> khdr support was a change originated from Linaro test ring. Undoing
> this might have implication on their workflow.

It shouldn't be a problem.
I've been running these patches through a smoke test and it looks
good.

Tested-by: Anders Roxell <anders.roxell@linaro.org>


Cheers,
Anders

>
> I will pull them into the discussion so they are aware of it and
> be prepared for this change.
>
> thanks,
> -- Shuah
>
>