Re: [PATCH dwarves v1 0/3] btf_encoder: support for BPF magic kernel functions

Alan Maguire
2025-11-04T21:00:06Z

On 29/10/2025 19:02, Ihor Solodrai wrote:
> This series implements BTF encoding of BPF kernel functions marked
> with KF_MAGIC_ARGS flag in pahole.
>
> The kfunc flag indicates that the arguments of a kfunc with __magic
> suffix are implicitly set by the verifier, and so pahole must emit two
> functions to BTF:
> * kfunc_impl() with the arguments matching kernel declaration
> * kfunc() with __magic arguments omitted
>
> For more details see relevant patch series for BPF:
> "bpf: magic kernel functions"
>
> This series is built upon KF_IMPLICIT_PROG_AUX_ARG support [1],
> although the approach changed signifcantly to call it a v2.
>
> [1] https://lore.kernel.org/dwarves/20250924211512.1287298-1-ihor.solodrai@linux.dev/
>
> Ihor Solodrai (3):
> btf_encoder: refactor btf_encoder__add_func_proto
> btf_encoder: factor out btf_encoder__add_bpf_kfunc()
> btf_encoder: support kfuncs with KF_MAGIC_ARGS flag
>
> btf_encoder.c | 292 ++++++++++++++++++++++++++++++++++++++------------
> 1 file changed, 222 insertions(+), 70 deletions(-)
>

seems like we could potentially pull in patches 1 and 2 as cleanups
prior to handling the KF_MAGIC/IMPLICIT change; would that be worthwhile?

Thanks!

Alan