Re: Linux 5.4 - bpf test build fails

[Cristian Marussi <cristian.marussi@arm.com>]

Hi Shuah

On 24/09/2019 16:26, Shuah Khan wrote:
> Hi Alexei and Daniel,
> 
> bpf test doesn't build on Linux 5.4 mainline. Do you know what's
> happening here.
> 
> 
> make -C tools/testing/selftests/bpf/

side question, since I'm writing arm64/ tests.

my "build-testcases" following the KSFT docs are:

make kselftest
make TARGETS=arm64 kselftest
make -C tools/testing/selftests/ 
make -C tools/testing/selftests/ INSTALL_PATH=<install-path> install
make TARGETS=arm64 -C tools/testing/selftests/ 
make TARGETS=arm64 -C tools/testing/selftests/ INSTALL_PATH=<install-path> install
./kselftest_install.sh <install-path>

(and related clean targets...)

but definitely NOT

make -C tools/testing/selftests/arm64

(for simplicity....due to the subdirs structure under tools/testing/selftests/arm64/)

am I wrong ?

Thanks

Cristian

> 
> -c progs/test_core_reloc_ptr_as_arr.c -o - || echo "clang failed") | \
> llc -march=bpf -mcpu=generic  -filetype=obj -o 
> /mnt/data/lkml/linux_5.4/tools/testing/selftests/bpf/test_core_reloc_ptr_as_arr.o
> progs/test_core_reloc_ptr_as_arr.c:25:6: error: use of unknown builtin
>        '__builtin_preserve_access_index' [-Wimplicit-function-declaration]
>          if (BPF_CORE_READ(&out->a, &in[2].a))
>              ^
> ./bpf_helpers.h:533:10: note: expanded from macro 'BPF_CORE_READ'
>                         __builtin_preserve_access_index(src))
>                         ^
> progs/test_core_reloc_ptr_as_arr.c:25:6: warning: incompatible integer to
>        pointer conversion passing 'int' to parameter of type 'const void *'
>        [-Wint-conversion]
>          if (BPF_CORE_READ(&out->a, &in[2].a))
>              ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> ./bpf_helpers.h:533:10: note: expanded from macro 'BPF_CORE_READ'
>                         __builtin_preserve_access_index(src))
>                         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> 1 warning and 1 error generated.
> llc: error: llc: <stdin>:1:1: error: expected top-level entity
> clang failed
> 
> Also
> 
> make TARGETS=bpf kselftest fails as well. Dependency between
> tools/lib/bpf and the test. How can we avoid this type of
> dependency or resolve it in a way it doesn't result in build
> failures?
> 
> thanks,
> -- Shuah
>