Em Tue, Jun 28, 2022 at 11:51:52AM +0200, Jiri Olsa escreveu:
> On Wed, Jun 15, 2022 at 04:03:06PM -0700, Yonghong Song wrote:
> > Add support for enum64. For 64-bit enumerator value,
> > previously, the value is truncated into 32bit, e.g.,
> > for the following enum in linux uapi bpf.h,
> > enum {
> > BPF_F_INDEX_MASK = 0xffffffffULL,
> > BPF_F_CURRENT_CPU = BPF_F_INDEX_MASK,
> > /* BPF_FUNC_perf_event_output for sk_buff input context. */
> > BPF_F_CTXLEN_MASK = (0xfffffULL << 32),
> > };
> >
> > BPF_F_CTXLEN_MASK will be encoded with 0 with BTF_KIND_ENUM
> > after pahole dwarf-to-btf conversion.
> > With this patch, the BPF_F_CTXLEN_MASK will be encoded properly
> > with BTF_KIND_ENUM64.
>
> yep, tried this on latest vmlinux and got:
>
> [705813] ENUM64 (anon) size=8
> BPF_F_INDEX_MASK val=4294967295
> BPF_F_CURRENT_CPU val=4294967295
> BPF_F_CTXLEN_MASK val=4503595332403200
>
> which is correct
>
> Tested-by: Jiri Olsa <jolsa@xxxxxxxxxx>
I'm testing with v3:
⬢[acme@toolbox pahole]$ pahole -JV vmlinux-v5.18-rc7+ | grep -B10 -A5 BPF_F_CTXLEN_MASK
BPF_FUNC_xdp_get_buff_len val=188
BPF_FUNC_xdp_load_bytes val=189
BPF_FUNC_xdp_store_bytes val=190
BPF_FUNC_copy_from_user_task val=191
BPF_FUNC_skb_set_tstamp val=192
BPF_FUNC_ima_file_hash val=193
__BPF_FUNC_MAX_ID val=194
[672880] ENUM64 (anon) size=8
BPF_F_INDEX_MASK val=4294967295
BPF_F_CURRENT_CPU val=4294967295
BPF_F_CTXLEN_MASK val=4503595332403200
[672881] ENUM (anon) size=4
BPF_F_GET_BRANCH_RECORDS_SIZE val=1
[672882] ARRAY (anon) type_id=672304 index_type_id=18 nr_elems=4
[672883] STRUCT (anon) size=16
tp_name type_id=672266 bits_offset=0
But:
⬢[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.
Jiri, can I keep your Tested-by for v3?
- Arnaldo
> jirka
>
> >
> > This patch is on top of tmp.master since tmp.master has not
> > been sync'ed with master branch yet.
> >
> > Changelogs:
> > v1 -> v2:
> > - Add flag --skip_encoding_btf_enum64 to disable newly-added functionality.
> >
> > Yonghong Song (2):
> > libbpf: Sync with latest libbpf repo
> > btf: Support BTF_KIND_ENUM64
> >
> > btf_encoder.c | 65 +++++++++++++++++++++++++++++++++++------------
> > btf_encoder.h | 2 +-
> > dwarf_loader.c | 12 +++++++++
> > dwarves.h | 4 ++-
> > dwarves_fprintf.c | 6 ++++-
> > lib/bpf | 2 +-
> > pahole.c | 10 +++++++-
> > 7 files changed, 80 insertions(+), 21 deletions(-)
> >
> > --
> > 2.30.2
> >
--
- Arnaldo
