From mboxrd@z Thu Jan  1 00:00:00 1970
Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand
        id S1751911AbeAJTzu (ORCPT <rfc822;ralf@linux-mips.org> + 1 other);
        Wed, 10 Jan 2018 14:55:50 -0500
Received: from Galois.linutronix.de ([146.0.238.70]:56886 "EHLO
        Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org
        with ESMTP id S1751295AbeAJTzt (ORCPT
        <rfc822;linux-kernel@vger.kernel.org>);
        Wed, 10 Jan 2018 14:55:49 -0500
Date: Wed, 10 Jan 2018 20:55:40 +0100 (CET)
From: Thomas Gleixner <tglx@linutronix.de>
To: Linus Torvalds <torvalds@linux-foundation.org>
cc: Borislav Petkov <bp@alien8.de>,
        David Woodhouse <dwmw2@infradead.org>,
        Andi Kleen <andi@firstfloor.org>,
        the arch/x86 maintainers <x86@kernel.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Paul Turner <pjt@google.com>,
        Andrew Lutomirski <luto@kernel.org>,
        Peter Zijlstra <peterz@infradead.org>,
        Tom Lendacky <thomas.lendacky@amd.com>,
        Tim Chen <tim.c.chen@linux.intel.com>,
        Greg Kroah-Hartman <gregkh@linux-foundation.org>,
        Dave Hansen <dave.hansen@intel.com>,
        Jiri Kosina <jikos@kernel.org>,
        Andi Kleen <ak@linux.intel.com>,
        Josh Poimboeuf <jpoimboe@redhat.com>
Subject: Re: [PATCH] x86/alternatives: Fix optimize_nops() checking
In-Reply-To: <CA+55aFz=yU7Q87ooyokssaFEGBx8BL+Vzs=4z+OOzvg-K5tfbA@mail.gmail.com>
Message-ID: <alpine.DEB.2.20.1801102053120.1919@nanos>
References: <20180110003139.10531-1-andi@firstfloor.org> <CA+55aFzyVFEUKaLpqxfwh5E9QFgMjzr+wVoYGxqTHVDkGcFkOw@mail.gmail.com> <1515568506.22302.72.camel@infradead.org> <1515578735.22302.91.camel@infradead.org> <20180110112815.mgciyf5acwacphkq@pd.tnic>
 <CA+55aFz=yU7Q87ooyokssaFEGBx8BL+Vzs=4z+OOzvg-K5tfbA@mail.gmail.com>
User-Agent: Alpine 2.20 (DEB 67 2015-01-07)
MIME-Version: 1.0
Content-Type: text/plain; charset=US-ASCII
Sender: linux-kernel-owner@vger.kernel.org
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org
Return-Path: <linux-kernel-owner@vger.kernel.org>

On Wed, 10 Jan 2018, Linus Torvalds wrote:

> On Wed, Jan 10, 2018 at 3:28 AM, Borislav Petkov <bp@alien8.de> wrote:
> >
> > Make sure we scan all bytes before we decide to optimize the NOPs in
> > there.
> 
> Can we also add compile-time checking (presumably in objtool, but who
> knows) that there are no relocations in the alternative section?

Cc'ing the overlor^Haded objtool wizard

> Because that was the other "oops, this really doesn't work with
> altinstructions" issue, wasn't it?

Yes.

Thanks,

	tglx