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From:   Nick Desaulniers <ndesaulniers@google.com>
Date:   Mon, 31 Jan 2022 12:45:20 -0800
Message-ID: <CAKwvOdnB=OfCc_31b=PMjxKewvb3CV2WDwhMWrigviWaHrGMhw@mail.gmail.com>
Subject: Re: [PATCH] objtool: prefer memory clobber & %= to volatile & __COUNTER__
To:     Segher Boessenkool <segher@kernel.crashing.org>,
        apinski@marvell.com
Cc:     Josh Poimboeuf <jpoimboe@redhat.com>,
        Borislav Petkov <bp@alien8.de>,
        Vasily Gorbik <gor@linux.ibm.com>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        Ingo Molnar <mingo@kernel.org>,
        Dave Hansen <dave.hansen@linux.intel.com>,
        Thomas Gleixner <tglx@linutronix.de>,
        Peter Zijlstra <peterz@infradead.org>,
        Luc Van Oostenryck <luc.vanoostenryck@gmail.com>,
        x86@kernel.org, llvm@lists.linux.dev, linux-sparse@vger.kernel.org,
        linux-kernel@vger.kernel.org, kernel test robot <lkp@intel.com>,
        Nathan Chancellor <nathan@kernel.org>,
        linux-toolchains@vger.kernel.org
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On Tue, Jan 25, 2022 at 3:34 PM Segher Boessenkool
<segher@kernel.crashing.org> wrote:
>
> Hi!
>
> On Mon, Jan 24, 2022 at 03:26:36PM -0800, Nick Desaulniers wrote:
> > I'm more confident that we can remove the `volatile` keyword (I was
> > thinking about adding a new diagnostic to clang to warn that volatile
> > is redundate+implied for asm goto or inline asm that doesn't have
> > outputs) though that's not the problem here and will probably generate
> > some kernel wide cleanup before we could enable such a flag.
>
> Its main value is that it would discourage users from thinking volatile
> is magic.  Seriously worth some pain!

https://reviews.llvm.org/D118297
PTAL
-- 
Thanks,
~Nick Desaulniers