| Message ID | 20230913142646.190047-4-alan.maguire@oracle.com (mailing list archive) |
|---|---|
| State | Not Applicable |
| Delegated to: | BPF |
| Headers | show |
| Series | dwarves: detect BTF kinds supported by kernel | expand |
| Context | Check | Description |
|---|---|---|
| netdev/tree_selection | success | Not a local patch |
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@oracle.com> > > --- > > 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); > > } > > } > >
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) +{ + __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); } }
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@oracle.com> --- btf_encoder.c | 24 ++++++++++++++++++++++++ btf_encoder.h | 2 ++ pahole.c | 2 ++ 3 files changed, 28 insertions(+)