linux-kernel - Re: [RFC][PATCH] objtool,x86_64: Replace recordmcount with objtool

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Message-ID: <20200722135829.7ca6fbc5@oasis.local.home>
Date:   Wed, 22 Jul 2020 13:58:36 -0400
From:   Steven Rostedt <rostedt@...dmis.org>
To:     Sami Tolvanen <samitolvanen@...gle.com>
Cc:     Peter Zijlstra <peterz@...radead.org>,
        Masahiro Yamada <masahiroy@...nel.org>,
        Will Deacon <will@...nel.org>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        "Paul E. McKenney" <paulmck@...nel.org>,
        Kees Cook <keescook@...omium.org>,
        Nick Desaulniers <ndesaulniers@...gle.com>,
        clang-built-linux <clang-built-linux@...glegroups.com>,
        Kernel Hardening <kernel-hardening@...ts.openwall.com>,
        linux-arch <linux-arch@...r.kernel.org>,
        linux-arm-kernel <linux-arm-kernel@...ts.infradead.org>,
        linux-kbuild <linux-kbuild@...r.kernel.org>,
        LKML <linux-kernel@...r.kernel.org>, linux-pci@...r.kernel.org,
        X86 ML <x86@...nel.org>, Josh Poimboeuf <jpoimboe@...hat.com>
Subject: Re: [RFC][PATCH] objtool,x86_64: Replace recordmcount with objtool

On Mon, 20 Jul 2020 09:52:37 -0700
Sami Tolvanen <samitolvanen@...gle.com> wrote:

> > Does x86 have a way to differentiate between the two that record mcount
> > can check?  
> 
> I'm not sure if looking at the relocation alone is sufficient on x86,
> we might also have to decode the instruction, which is what objtool
> does. Did you have any thoughts on Peter's patch, or my initial
> suggestion, which adds a __nomcount attribute to affected functions?

There's a lot of code in this thread. Can you give me the message-id of
Peter's patch in question.

Thanks,

-- Steve