Re: [PATCH bpf v2 4/6] tools: bpf: sync bpf uapi header

From: Alexei Starovoitov <alexei.starovoitov@gmail.com>
To: Sandipan Das <sandipan@linux.vnet.ibm.com>
Cc: Alexei Starovoitov <ast@kernel.org>,
	Daniel Borkmann <daniel@iogearbox.net>,
	Network Development <netdev@vger.kernel.org>,
	linuxppc-dev@lists.ozlabs.org,
	"Naveen N. Rao" <naveen.n.rao@linux.vnet.ibm.com>,
	Michael Ellerman <mpe@ellerman.id.au>,
	Jakub Kicinski <jakub.kicinski@netronome.com>
Subject: Re: [PATCH bpf v2 4/6] tools: bpf: sync bpf uapi header
Date: Fri, 18 May 2018 09:08:42 -0700	[thread overview]
Message-ID: <CAADnVQKzBdSLNXEmd47xTv15caXWp6JTCAnHD3n7Trbr9BZq4A@mail.gmail.com> (raw)

On Fri, May 18, 2018 at 5:50 AM, Sandipan Das
<sandipan@linux.vnet.ibm.com> wrote:
> Syncing the bpf.h uapi header with tools so that struct
> bpf_prog_info has the two new fields for passing on the
> addresses of the kernel symbols corresponding to each
> function in a JITed program.
>
> Signed-off-by: Sandipan Das <sandipan@linux.vnet.ibm.com>
> ---
>  tools/include/uapi/linux/bpf.h | 2 ++
>  1 file changed, 2 insertions(+)
>
> diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h
> index d94d333a8225..040c9cac7303 100644
> --- a/tools/include/uapi/linux/bpf.h
> +++ b/tools/include/uapi/linux/bpf.h
> @@ -2188,6 +2188,8 @@ struct bpf_prog_info {
>         __u32 xlated_prog_len;
>         __aligned_u64 jited_prog_insns;
>         __aligned_u64 xlated_prog_insns;
> +       __aligned_u64 jited_ksyms;
> +       __u32 nr_jited_ksyms;
>         __u64 load_time;        /* ns since boottime */
>         __u32 created_by_uid;
>         __u32 nr_map_ids;

this breaks uapi.
New fields can only be added to the end.