Re: [PATCH bpf-next 1/3] selftests/bpf: Use cpu_number only on arches that have it

[Andrii Nakryiko <andrii.nakryiko@gmail.com>]

On Tue, Oct 12, 2021 at 4:51 AM Ilya Leoshkevich <iii@linux.ibm.com> wrote:
>
> cpu_number exists only on Intel and aarch64, so skip the test involing
> it on other arches. An alternative would be to replace it with an
> exported non-ifdefed primitive-typed percpu variable from the common
> code, but there appears to be none.
>
> Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
> ---
>  tools/testing/selftests/bpf/prog_tests/btf_dump.c | 2 ++
>  1 file changed, 2 insertions(+)
>
> diff --git a/tools/testing/selftests/bpf/prog_tests/btf_dump.c b/tools/testing/selftests/bpf/prog_tests/btf_dump.c
> index 87f9df653e4e..12f457b6786d 100644
> --- a/tools/testing/selftests/bpf/prog_tests/btf_dump.c
> +++ b/tools/testing/selftests/bpf/prog_tests/btf_dump.c
> @@ -778,8 +778,10 @@ static void test_btf_dump_struct_data(struct btf *btf, struct btf_dump *d,
>  static void test_btf_dump_var_data(struct btf *btf, struct btf_dump *d,
>                                    char *str)
>  {
> +#if defined(__i386__) || defined(__x86_64__) || defined(__aarch64__)
>         TEST_BTF_DUMP_VAR(btf, d, NULL, str, "cpu_number", int, BTF_F_COMPACT,
>                           "int cpu_number = (int)100", 100);
> +#endif

We are in the talks about supporting cross-compilation of selftests,
and this will be just another breakage that we'll have to undo.

Can we find some other variable that will be available on all
architectures? Maybe "runqueues"?

>         TEST_BTF_DUMP_VAR(btf, d, NULL, str, "cpu_profile_flip", int, BTF_F_COMPACT,
>                           "static int cpu_profile_flip = (int)2", 2);
>  }
> --
> 2.31.1
>