Re: [PATCH dwarves v2 0/2] btf: support BTF_KIND_ENUM64

[Jiri Olsa <olsajiri@gmail.com>]

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@kernel.org>

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
>