On Wed, May 28, 2025 at 2:58 AM Alan Maguire <alan.maguire@xxxxxxxxxx> wrote:
>
> This allows BTF parsing to proceed even if we do not know the
> kind.
>
> Signed-off-by: Alan Maguire <alan.maguire@xxxxxxxxxx>
> ---
> tools/lib/bpf/btf.c | 35 ++++++++++++++++++++++++++++-------
> 1 file changed, 28 insertions(+), 7 deletions(-)
>
> diff --git a/tools/lib/bpf/btf.c b/tools/lib/bpf/btf.c
> index 43d1fce8977c..7a197dbfc689 100644
> --- a/tools/lib/bpf/btf.c
> +++ b/tools/lib/bpf/btf.c
> @@ -355,7 +355,29 @@ static int btf_parse_kind_layout_sec(struct btf *btf)
> return 0;
> }
>
> -static int btf_type_size(const struct btf_type *t)
> +/* for unknown kinds, consult kind layout. */
> +static int btf_type_size_unknown(const struct btf *btf, const struct btf_type *t)
> +{
> + int size = sizeof(struct btf_type);
> + struct btf_kind_layout *k = NULL;
> + __u16 vlen = btf_vlen(t);
> + __u8 kind = btf_kind(t);
> +
> + if (btf->kind_layout)
> + k = &((struct btf_kind_layout *)btf->kind_layout)[kind];
> +
> + if (!k || (void *)k > ((void *)btf->kind_layout + btf->hdr->kind_layout_len)) {
> + pr_debug("Unsupported BTF_KIND: %u\n", btf_kind(t));
> + return -EINVAL;
I'm missing the point around kind_layout->flags.
I was expecting that this helper and others at least
would check that flags == 0, but none of it is happening.
The patches say that flags is unused and do nothing.
Why add flags field at all?
> + }
> +
> + size += k->info_sz;
> + size += vlen * k->elem_sz;
> +
> + return size;
> +}
