linux-kernel - Re: [PATCH] objtool: Disable stack validation when CROSS

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Message-ID: <20160302211726.GA23501@treble.redhat.com>
Date:	Wed, 2 Mar 2016 15:17:26 -0600
From:	Josh Poimboeuf <jpoimboe@...hat.com>
To:	Stephen Rothwell <sfr@...b.auug.org.au>
Cc:	Ingo Molnar <mingo@...nel.org>,
	Thomas Gleixner <tglx@...utronix.de>,
	Ingo Molnar <mingo@...e.hu>, "H. Peter Anvin" <hpa@...or.com>,
	Peter Zijlstra <peterz@...radead.org>,
	linux-next@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] objtool: Disable stack validation when CROSS_COMPILE is
 used

On Wed, Mar 02, 2016 at 01:27:35PM +1100, Stephen Rothwell wrote:
> Hi Josh,
> 
> On Tue, 1 Mar 2016 15:54:51 -0600 Josh Poimboeuf <jpoimboe@...hat.com> wrote:
> >
> > Changing it to use the host compiler would probably be an easy fix, but
> > that would expose a harder bug related to endianness.
> 
> Just by luck, my PowerPC host is little endian :-)

Aha!  In that case, I think I'll take a different approach and try to
add support for CROSS_COMPILE.

We'll need it anyway, later on, when we port objtool to more
architectures.

> > How about the below workaround patch to disable objtool and warn when
> > CROSS_COMPILE is used?  If anybody complains about lack of cross-compile
> > support later, we could try to fix it then.
> 
> This seems reasonable.
> 
> > From a3c65947011a420743f308b698171c4209105d3f Mon Sep 17 00:00:00 2001
> > Message-Id: <a3c65947011a420743f308b698171c4209105d3f.1456868910.git.jpoimboe@...hat.com>
> > From: Josh Poimboeuf <jpoimboe@...hat.com>
> > Date: Tue, 1 Mar 2016 13:35:51 -0600
> > Subject: [PATCH] objtool: Disable stack validation when CROSS_COMPILE is used
> 
> I have applied this to the merge of the tip tree in linux-next today
> and it compiles fine for me.  I will continue applying it until
> something better comes along or it is applied to the tip tree.

Thanks.  I should have the patch(es) soon.  If/when they get merged,
I'll let you know, and then you can drop this one.

-- 
Josh