Re: [PATCH ipsec-next v3 4/9] bpf: selftests: test_loader: Support __btf_path() annotation

[Andrii Nakryiko]

On Fri, Dec 1, 2023 at 12:24 PM Daniel Xu <dxu@xxxxxxxxx> wrote:
>
> This commit adds support for per-prog btf_custom_path. This is necessary
> for testing CO-RE relocations on non-vmlinux types using test_loader
> infrastructure.
>
> Signed-off-by: Daniel Xu <dxu@xxxxxxxxx>
> ---
>  tools/testing/selftests/bpf/progs/bpf_misc.h | 1 +
>  tools/testing/selftests/bpf/test_loader.c    | 7 +++++++
>  2 files changed, 8 insertions(+)
>

Acked-by: Andrii Nakryiko <andrii@xxxxxxxxxx>


> diff --git a/tools/testing/selftests/bpf/progs/bpf_misc.h b/tools/testing/selftests/bpf/progs/bpf_misc.h
> index 799fff4995d8..2fd59970c43a 100644
> --- a/tools/testing/selftests/bpf/progs/bpf_misc.h
> +++ b/tools/testing/selftests/bpf/progs/bpf_misc.h
> @@ -71,6 +71,7 @@
>  #define __retval_unpriv(val)   __attribute__((btf_decl_tag("comment:test_retval_unpriv="#val)))
>  #define __auxiliary            __attribute__((btf_decl_tag("comment:test_auxiliary")))
>  #define __auxiliary_unpriv     __attribute__((btf_decl_tag("comment:test_auxiliary_unpriv")))
> +#define __btf_path(path)       __attribute__((btf_decl_tag("comment:test_btf_path=" path)))
>
>  /* Convenience macro for use with 'asm volatile' blocks */
>  #define __naked __attribute__((naked))
> diff --git a/tools/testing/selftests/bpf/test_loader.c b/tools/testing/selftests/bpf/test_loader.c
> index a350ecdfba4a..74ceb7877ae2 100644
> --- a/tools/testing/selftests/bpf/test_loader.c
> +++ b/tools/testing/selftests/bpf/test_loader.c
> @@ -27,6 +27,7 @@
>  #define TEST_TAG_RETVAL_PFX_UNPRIV "comment:test_retval_unpriv="
>  #define TEST_TAG_AUXILIARY "comment:test_auxiliary"
>  #define TEST_TAG_AUXILIARY_UNPRIV "comment:test_auxiliary_unpriv"
> +#define TEST_BTF_PATH "comment:test_btf_path="
>
>  /* Warning: duplicated in bpf_misc.h */
>  #define POINTER_VALUE  0xcafe4all
> @@ -58,6 +59,7 @@ struct test_spec {
>         const char *prog_name;
>         struct test_subspec priv;
>         struct test_subspec unpriv;
> +       const char *btf_custom_path;
>         int log_level;
>         int prog_flags;
>         int mode_mask;
> @@ -288,6 +290,8 @@ static int parse_test_spec(struct test_loader *tester,
>                                         goto cleanup;
>                                 update_flags(&spec->prog_flags, flags, clear);
>                         }
> +               } else if (str_has_pfx(s, TEST_BTF_PATH)) {
> +                       spec->btf_custom_path = s + sizeof(TEST_BTF_PATH) - 1;
>                 }
>         }
>
> @@ -578,6 +582,9 @@ void run_subtest(struct test_loader *tester,
>                 }
>         }
>
> +       /* Implicitly reset to NULL if next test case doesn't specify */
> +       open_opts->btf_custom_path = spec->btf_custom_path;
> +
>         tobj = bpf_object__open_mem(obj_bytes, obj_byte_cnt, open_opts);
>         if (!ASSERT_OK_PTR(tobj, "obj_open_mem")) /* shouldn't happen */
>                 goto subtest_cleanup;
> --
> 2.42.1
>