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From:   Alexei Starovoitov <alexei.starovoitov@gmail.com>
Date:   Thu, 24 Mar 2022 19:41:01 -0700
Message-ID: <CAADnVQ+uFiFJKPcsPuLW2CU+VfoSLM4fL1KzJWC2ZXEMt7jHAQ@mail.gmail.com>
Subject: Re: [PATCH v13 bpf-next 1/1] rethook: x86: Add rethook x86 implementation
To:     Masami Hiramatsu <mhiramat@kernel.org>
Cc:     Peter Zijlstra <peterz@infradead.org>,
        Thomas Gleixner <tglx@linutronix.de>,
        Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
        Dave Hansen <dave.hansen@linux.intel.com>,
        X86 ML <x86@kernel.org>, Jiri Olsa <jolsa@kernel.org>,
        Alexei Starovoitov <ast@kernel.org>,
        Andrii Nakryiko <andrii.nakryiko@gmail.com>,
        Daniel Borkmann <daniel@iogearbox.net>,
        Andrii Nakryiko <andrii@kernel.org>,
        Network Development <netdev@vger.kernel.org>,
        bpf <bpf@vger.kernel.org>, lkml <linux-kernel@vger.kernel.org>,
        Martin KaFai Lau <kafai@fb.com>,
        Song Liu <songliubraving@fb.com>, Yonghong Song <yhs@fb.com>,
        John Fastabend <john.fastabend@gmail.com>,
        KP Singh <kpsingh@chromium.org>,
        Steven Rostedt <rostedt@goodmis.org>,
        "Naveen N . Rao" <naveen.n.rao@linux.ibm.com>,
        Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>,
        "David S . Miller" <davem@davemloft.net>
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On Thu, Mar 24, 2022 at 7:21 PM Masami Hiramatsu <mhiramat@kernel.org> wrote:
>
> On Thu, 24 Mar 2022 19:03:43 -0700
> Alexei Starovoitov <alexei.starovoitov@gmail.com> wrote:
>
> > On Wed, Mar 23, 2022 at 4:41 AM Masami Hiramatsu <mhiramat@kernel.org> wrote:
> > >
> > > On Wed, 23 Mar 2022 09:05:26 +0100
> > > Peter Zijlstra <peterz@infradead.org> wrote:
> > >
> > > > On Wed, Mar 23, 2022 at 11:34:59AM +0900, Masami Hiramatsu wrote:
> > > > > Add rethook for x86 implementation. Most of the code has been copied from
> > > > > kretprobes on x86.
> > > >
> > > > Right; as said, I'm really unhappy with growing a carbon copy of this
> > > > stuff instead of sharing. Can we *please* keep it a single instance?
> > >
> > > OK, then let me update the kprobe side too.
> > >
> > > > Them being basically indentical, it should be trivial to have
> > > > CONFIG_KPROBE_ON_RETHOOK (or somesuch) and just share this.
> > >
> > > Yes, ideally it should use CONFIG_HAVE_RETHOOK since the rethook arch port
> > > must be a copy of the kretprobe implementation. But for safety, I think
> > > having CONFIG_KPROBE_ON_RETHOOK is a good idea until replacing all kretprobe
> > > implementations.
> >
> > Masami,
> >
> > you're respinning this patch to combine
> > arch_rethook_trampoline and __kretprobe_trampoline
> > right?
>
> Yes, let me send the first patch set (for x86 at first).

great

> BTW, can you review these 2 patches? These are only for the fprobes,
> so it can be picked to bpf-next.
>
> https://lore.kernel.org/all/164802091567.1732982.1242854551611267542.stgit@devnote2/T/#u

Yes. They look good. Will push them soon.