Hi Lorenz,

On Mon, Jan 08, 2024 at 10:15:45AM +0100, Lorenz Bauer wrote:

On Sat, Jan 6, 2024 at 7:25 PM Daniel Xu [off-list ref] wrote:

quoted

=== Description ===

This is a bpf-treewide change that annotates all kfuncs as such inside
.BTF_ids. This annotation eventually allows us to automatically generate
kfunc prototypes from bpftool.

We store this metadata inside a yet-unused flags field inside struct
btf_id_set8 (thanks Kumar!). pahole will be taught where to look.

This is great, thanks for tackling this. With yout patches we can
figure out the full set of kfuncs. Is there a way to extend it so that
we can tell which program context a kfunc can be called from?

I think a potential approach would be to extend BTF_ID_FLAGS() with some
more flags if we want to continue with .BTF_ids parsing technique. But
it has some issues with program-type-less helpers that are associated with
attachpoints as well as struct_ops helpers.

Since it looks like we're in rather early stages of program-type-less
world, maybe it'd be good to defer solving this problem until more use
cases are established and we can find a good cut point to design around.
Even with uapi helpers there was no way before.

Thanks,
Daniel