From: Alexei Starovoitov <alexei.starovoitov@gmail.com>
To: Lorenz Bauer <lmb@cloudflare.com>
Cc: Andrii Nakryiko <andrii.nakryiko@gmail.com>,
bpf <bpf@vger.kernel.org>, Andrii Nakryiko <andrii@kernel.org>,
Florent Revest <revest@chromium.org>
Subject: Re: Portability of bpf_tracing.h
Date: Thu, 10 Jun 2021 11:14:01 -0700 [thread overview]
Message-ID: <CAADnVQJu0gbKXLYQ_whsh0sENkxR7E3XOuVfAFrPkyXhQtdG1g@mail.gmail.com> (raw)
In-Reply-To: <CACAyw99m8rbE5L9LAowYwvAkza+twuet2tdas2eotsf3uWgGTQ@mail.gmail.com>
On Thu, Jun 10, 2021 at 7:12 AM Lorenz Bauer <lmb@cloudflare.com> wrote:
> > > The idea of basing this on unique fields in types is neat, the
> > > downside I see is that we encode the logic in the BPF bitstream. If in
> > > the future struct pt_regs is changed, code breaks and we can't do much
> >
> > If pt_regs fields are renamed all PT_REGS-related stuff, provided by
> > libbpf in bpf_tracing.h will break as well and will require
> > re-compilation of BPF application.
>
> I'm thinking more along the lines of, if a PT_REGS definition changes
> so that the unique field isn't unique anymore. The BPF is still valid,
> but the logic that determines the platform isn't.
struct pt_regs is uapi on every arch.
They cannot change. New registers can be added :) but the chance is
close to zero.
prev parent reply other threads:[~2021-06-10 18:15 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-05-24 15:05 Portability of bpf_tracing.h Lorenz Bauer
2021-05-24 17:47 ` Andrii Nakryiko
2021-05-24 19:30 ` John Fastabend
2021-05-25 0:13 ` Andrii Nakryiko
2021-05-26 9:13 ` Lorenz Bauer
2021-05-26 18:34 ` Andrii Nakryiko
2021-05-28 8:29 ` Lorenz Bauer
2021-05-30 0:51 ` Andrii Nakryiko
2021-06-10 14:09 ` Lorenz Bauer
2021-06-10 18:14 ` Alexei Starovoitov [this message]
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