Re: selftests/bpf doesn't compile

[shuah]

Hi Geert,

On 1/4/19 10:16 AM, Geert Uytterhoeven wrote:
> Hi Shuah,
>
> CC kbuild, gpio
>
> On Thu, Sep 14, 2017 at 5:34 PM Shuah Khan <shuah@xxxxxxxxxx> wrote:
> > bpf test depends on clang and fails to compile when
> >
> > ------------------------------------------------------
> > make -C tools/testing/selftests/bpf run_tests
> >
> >
> > make: clang: Command not found
> > Makefile:39: recipe for target '.linux-kselftest/tools/testing/selftests/bpf/test_pkt_access.o' failed
> > make: *** [./linux-kselftest/tools/testing/selftests/bpf/test_pkt_access.o] Error 127
> > make: Leaving directory '.linux-kselftest/tools/testing/selftests/bpf'
>
> The above failure is indeed due to missing clang.
>
> > With "make TARGETS=bpf kselftest" it fails earlier:
> >
> > make[3]: Entering directory './linux-kselftest/tools/lib/bpf'
> > Makefile:40: tools/scripts/Makefile.arch: No such file or directory
> > Makefile:84: tools/build/Makefile.feature: No such file or directory
> > Makefile:143: tools/build/Makefile.include: No such file or directory
>
> This is due to srctree being "." instead of the actual source tree,
> when invoked as "make kselftest".
> When using "make -C tools/testing/selftests", srctree is correct.
>
> tools/testing/selftests/bpf/Makefile has:
>
>      $(BPFOBJ): force
>              $(MAKE) -C $(BPFDIR) OUTPUT=$(OUTPUT)/
>
> to enter the tools/lib/bpf directory to force a build of libbpf.a
>
> Note that tools/gpio has the same issue.
>
> There seem to be _four_ different ways to build kselftests
> (Documentation/dev-tools/kselftest.rst):
>
>      make kselftest
>      make O=/path/to/output kselftest
>      make -C tools/testing/selftests
>      make O=/path/to/output -C tools/testing/selftests
>
> I'm not so fond of the latter two, as they basically run make from
> somewhere inside the tree, which complicates things. I believe we don't
> support this anywhere else.
>
> Each of the four seem to have (different) issues. Especially when you
> throw cross-compiling into the mix. And care about where installed
> headers end up (yes, kselftest calls headers_install internally).
>
> I'm working on fixes for some of them, but I don't know how to fix the
> srctree issue.

I will take a look at the srctree problem and fix it. I have had to fix
a few individual test Makefiles after ksefltest headers_install went in.

It will be in a week or two. I am taking some time off this week and
next week other than for occasional email checking.

thanks,
-- Shuah