On Wed, Jun 29, 2022 at 9:56 AM Arnaldo Carvalho de Melo
<acme@xxxxxxxxxx> wrote:
>
> Em Wed, Jun 29, 2022 at 01:30:10PM -0300, Arnaldo Carvalho de Melo escreveu:
> > ⬢[acme@toolbox pahole]$ pdwtags -F btf vmlinux-v5.18-rc7+ | grep -B10 -A5 BPF_F_CTXLEN_MASK
> > BTF: idx: 4173, Unknown kind 19
> > BTF: idx: 4975, Unknown kind 19
> > BTF: idx: 6673, Unknown kind 19
> > BTF: idx: 27413, Unknown kind 19
> > BTF: idx: 30626, Unknown kind 19
> > BTF: idx: 30829, Unknown kind 19
> > BTF: idx: 38040, Unknown kind 19
> > BTF: idx: 56969, Unknown kind 19
> > BTF: idx: 83004, Unknown kind 19
> > ⬢[acme@toolbox pahole]$
> >
> > Ok, I need to update pahole's BTF loader to support:
> >
> > lib/bpf/src/btf.h:#define BTF_KIND_ENUM64 19 /* Enum for up-to 64bit values */
> >
> >
> > Working on it now.
>
> ⬢[acme@toolbox pahole]$ pdwtags -F btf vmlinux-v5.18-rc7+ | grep -B5 -A5 BPF_F_CTXLEN_MASK
>
> /* 27413 */
> enum {
> BPF_F_INDEX_MASK = 4294967295,
> BPF_F_CURRENT_CPU = 4294967295,
> BPF_F_CTXLEN_MASK = 4503595332403200,
> } __attribute__((__packed__)); /* size: 8 */
>
> /* 27414 */
> enum {
> BPF_F_GET_BRANCH_RECORDS_SIZE = 1,
> ⬢[acme@toolbox pahole]$
>
> Quick patch here, please Ack, if possible:
>
two minor nits, but looks good overall:
Acked-by: Andrii Nakryiko <andrii@xxxxxxxxxx>
> diff --git a/btf_loader.c b/btf_loader.c
> index b5d444643adf30b1..e57ecce2cde26e4e 100644
> --- a/btf_loader.c
> +++ b/btf_loader.c
> @@ -312,6 +312,49 @@ out_free:
> return -ENOMEM;
> }
>
> +static struct enumerator *enumerator__new64(const char *name, uint64_t value)
> +{
> + struct enumerator *en = tag__alloc(sizeof(*en));
> +
> + if (en != NULL) {
> + en->name = name;
> + en->value = value; // Value is already 64-bit, as this is used with DWARF as well
> + en->tag.tag = DW_TAG_enumerator;
> + }
> +
> + return en;
> +}
> +
> +static int create_new_enumeration64(struct cu *cu, const struct btf_type *tp, uint32_t id)
> +{
> + struct btf_enum64 *ep = btf_enum64(tp);
> + uint16_t i, vlen = btf_vlen(tp);
> + struct type *enumeration = type__new(DW_TAG_enumeration_type,
> + cu__btf_str(cu, tp->name_off),
> + tp->size ? tp->size * 8 : (sizeof(int) * 8));
tp->size should always be valid, so this fall back to sizeof(int)
isn't necessary
> +
> + if (enumeration == NULL)
> + return -ENOMEM;
> +
> + for (i = 0; i < vlen; i++) {
> + const char *name = cu__btf_str(cu, ep[i].name_off);
> + uint64_t value = ((uint64_t)ep[i].val_hi32) << 32 | ep[i].val_lo32;
use btf_enum64_value() defined in libbpf's btf.h header
> + struct enumerator *enumerator = enumerator__new64(name, value);
> +
> + if (enumerator == NULL)
> + goto out_free;
> +
> + enumeration__add(enumeration, enumerator);
> + }
> +
> + cu__add_tag_with_id(cu, &enumeration->namespace.tag, id);
> +
> + return 0;
> +out_free:
> + enumeration__delete(enumeration);
> + return -ENOMEM;
> +}
> +
> static int create_new_subroutine_type(struct cu *cu, const struct btf_type *tp, uint32_t id)
> {
> struct ftype *proto = tag__alloc(sizeof(*proto));
> @@ -419,6 +462,9 @@ static int btf__load_types(struct btf *btf, struct cu *cu)
> case BTF_KIND_ENUM:
> err = create_new_enumeration(cu, type_ptr, type_index);
> break;
> + case BTF_KIND_ENUM64:
> + err = create_new_enumeration64(cu, type_ptr, type_index);
> + break;
> case BTF_KIND_FWD:
> err = create_new_forward_decl(cu, type_ptr, type_index);
> break;
