Re: [PATCH 2/4] selftests: Fix seccomp to support relocatable build (O=objdir)

[Shuah Khan]

On 3/4/20 5:22 PM, Michael Ellerman wrote:
> Shuah Khan <skhan@xxxxxxxxxxxxxxxxxxx> writes:
> > On 3/4/20 3:42 PM, Kees Cook wrote:
> > > On Wed, Mar 04, 2020 at 03:13:33PM -0700, Shuah Khan wrote:
> > > > Fix seccomp relocatable builds. This is a simple fix to use the
> > > > right lib.mk variable TEST_GEN_PROGS for objects to leverage
> > > > lib.mk common framework for relocatable builds.
> > > >
> > > > Signed-off-by: Shuah Khan <skhan@xxxxxxxxxxxxxxxxxxx>
> > > > ---
> > > >    tools/testing/selftests/seccomp/Makefile | 16 +++-------------
> > > >    1 file changed, 3 insertions(+), 13 deletions(-)
> > > >
> > > > diff --git a/tools/testing/selftests/seccomp/Makefile b/tools/testing/selftests/seccomp/Makefile
> > > > index 1760b3e39730..a8a9717fc1be 100644
> > > > --- a/tools/testing/selftests/seccomp/Makefile
> > > > +++ b/tools/testing/selftests/seccomp/Makefile
> > > > @@ -1,17 +1,7 @@
> > > >    # SPDX-License-Identifier: GPL-2.0
> > > > -all:
> > > > -
> > > > -include ../lib.mk
> > > > -
> > > > -.PHONY: all clean
> > > > -
> > > > -BINARIES := seccomp_bpf seccomp_benchmark
> > > >    CFLAGS += -Wl,-no-as-needed -Wall
> > > > +LDFLAGS += -lpthread
> > > >    
> > > > -seccomp_bpf: seccomp_bpf.c ../kselftest_harness.h
> > >
> > > How is the ../kselftest_harness.h dependency detected in the resulting
> > > build rules?
> > >
> > > Otherwise, looks good.
> >
> > Didn't see any problems. I will look into adding the dependency.
>
> Before:
>
>    $ make --no-print-directory -C tools/testing/selftests/ TARGETS=seccomp
>    make --no-builtin-rules INSTALL_HDR_PATH=$BUILD/usr \
>            ARCH=powerpc -C ../../.. headers_install
>      INSTALL /home/michael/build/adhoc/kselftest/usr/include
>    gcc -Wl,-no-as-needed -Wall  seccomp_bpf.c -lpthread -o seccomp_bpf
>    gcc -Wl,-no-as-needed -Wall    seccomp_benchmark.c   -o seccomp_benchmark
>    
>    $ touch tools/testing/selftests/kselftest_harness.h
>    
>    $ make --no-print-directory -C tools/testing/selftests/ TARGETS=seccomp
>    make --no-builtin-rules INSTALL_HDR_PATH=$BUILD/usr \
>            ARCH=powerpc -C ../../.. headers_install
>      INSTALL /home/michael/build/adhoc/kselftest/usr/include
>    gcc -Wl,-no-as-needed -Wall  seccomp_bpf.c -lpthread -o seccomp_bpf
>    $
>
> Note that touching the header causes it to rebuild seccomp_bpf.
>
> With this patch applied:
>
>    $ make --no-print-directory -C tools/testing/selftests/ TARGETS=seccomp
>    make -s --no-builtin-rules INSTALL_HDR_PATH=$BUILD/usr \
>            ARCH=powerpc -C ../../.. headers_install
>    gcc -Wl,-no-as-needed -Wall  -lpthread  seccomp_bpf.c  -o /home/michael/build/adhoc/kselftest/seccomp/seccomp_bpf
>    gcc -Wl,-no-as-needed -Wall  -lpthread  seccomp_benchmark.c  -o /home/michael/build/adhoc/kselftest/seccomp/seccomp_benchmark
>    
>    $ touch tools/testing/selftests/kselftest_harness.h
>    
>    $ make --no-print-directory -C tools/testing/selftests/ TARGETS=seccomp
>    make -s --no-builtin-rules INSTALL_HDR_PATH=$BUILD/usr \
>            ARCH=powerpc -C ../../.. headers_install
>    make[1]: Nothing to be done for 'all'.
>    $

Thanks. I realized I overlooked header dependency case.

> So yeah it still needs:
>
> seccomp_bpf: ../kselftest_harness.h
Yes v2 coming up. It also has to handle OUTPUT relocation.

thanks,
-- Shuah