On Wed, 2023-09-13 at 15:26 +0100, Alan Maguire wrote:
> > When creating module BTF, the module likely will not have a DWARF
> > specificiation of BTF_KIND_MAX, so look for it in the base BTF. For
> > vmlinux base BTF, the enumeration value is present, so the base BTF
> > can be checked to limit BTF kind representation.
> >
> > Signed-off-by: Alan Maguire <alan.maguire@xxxxxxxxxx>
> > ---
> > btf_encoder.c | 24 ++++++++++++++++++++++++
> > btf_encoder.h | 2 ++
> > pahole.c | 2 ++
> > 3 files changed, 28 insertions(+)
> >
> > diff --git a/btf_encoder.c b/btf_encoder.c
> > index ad0158f..6cb3df6 100644
> > --- a/btf_encoder.c
> > +++ b/btf_encoder.c
> > @@ -1902,3 +1902,27 @@ void dwarves__set_btf_kind_max(struct conf_load *conf_load, int btf_kind_max)
> > if (btf_kind_max < BTF_KIND_ENUM64)
> > conf_load->skip_encoding_btf_enum64 = true;
> > }
> > +
> > +void btf__set_btf_kind_max(struct conf_load *conf_load, struct btf *btf)
> > +{
Nitpick: same function for DWARF has name dwarf__find_btf_kind_max,
which seems to be a bit inconsistent.
> > + __u32 id, type_cnt = btf__type_cnt(btf);
> > +
> > + for (id = 1; id < type_cnt; id++) {
> > + const struct btf_type *t = btf__type_by_id(btf, id);
> > + const struct btf_enum *e;
> > + __u16 vlen, i;
> > +
> > + if (!t || !btf_is_enum(t))
> > + continue;
> > + vlen = btf_vlen(t);
> > + e = btf_enum(t);
> > + for (i = 0; i < vlen; e++, i++) {
> > + const char *name = btf__name_by_offset(btf, e->name_off);
> > +
> > + if (!name || strcmp(name, "BTF_KIND_MAX"))
> > + continue;
> > + dwarves__set_btf_kind_max(conf_load, e->val);
> > + return;
> > + }
> > + }
> > +}
> > diff --git a/btf_encoder.h b/btf_encoder.h
> > index 34516bb..e5e12ef 100644
> > --- a/btf_encoder.h
> > +++ b/btf_encoder.h
> > @@ -27,4 +27,6 @@ struct btf *btf_encoder__btf(struct btf_encoder *encoder);
> >
> > int btf_encoder__add_encoder(struct btf_encoder *encoder, struct btf_encoder *other);
> >
> > +void btf__set_btf_kind_max(struct conf_load *conf_load, struct btf *btf);
> > +
> > #endif /* _BTF_ENCODER_H_ */
> > diff --git a/pahole.c b/pahole.c
> > index aca2704..4d6d059 100644
> > --- a/pahole.c
> > +++ b/pahole.c
> > @@ -3470,6 +3470,7 @@ int main(int argc, char *argv[])
> > base_btf_file, libbpf_get_error(conf_load.base_btf));
> > goto out;
> > }
> > + btf__set_btf_kind_max(&conf_load, conf_load.base_btf);
> > if (!btf_encode && !ctf_encode) {
> > // Force "btf" since a btf_base is being informed
> > conf_load.format_path = "btf";
> > @@ -3513,6 +3514,7 @@ try_sole_arg_as_class_names:
> > base_btf_file, libbpf_get_error(conf_load.base_btf));
> > goto out;
> > }
> > + btf__set_btf_kind_max(&conf_load, conf_load.base_btf);
> > }
> > }
> >
