Re: [PATCH 1/5] kexec: Fix make headers_check

From: Geoff Levand <geoff@infradead.org>
To: Paul Bolle <pebolle@tiscali.nl>,
	Andrew Morton <akpm@linux-foundation.org>
Cc: Vivek Goyal <vgoyal@redhat.com>, "H. Peter Anvin" <hpa@zytor.com>,
	Eric Biederman <ebiederm@xmission.com>,
	Benjamin Herrenschmidt <benh@kernel.crashing.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	kexec@lists.infradead.org, linuxppc-dev@lists.ozlabs.org,
	linux-kernel@vger.kernel.org, maximilian attems <max@stro.at>
Subject: Re: [PATCH 1/5] kexec: Fix make headers_check
Date: Mon, 06 Oct 2014 10:34:37 -0700	[thread overview]
Message-ID: <1412616877.32313.55.camel@smoke> (raw)
In-Reply-To: <1412604734.4054.72.camel@x220>

Hi,

On Mon, 2014-10-06 at 16:12 +0200, Paul Bolle wrote:
> On Sat, 2014-08-30 at 14:47 +0200, Paul Bolle wrote:
> > [Added Peter Anvin.]
> > 
> > On Mon, 2014-08-25 at 13:22 -0400, Vivek Goyal wrote:
> > > On Fri, Aug 22, 2014 at 06:39:47PM +0000, Geoff Levand wrote:
> > > > Remove the unneded declaration for a kexec_load() routine.
> > > > 
> > > > Fixes errors like these when running 'make headers_check':
> > > > 
> > > > include/uapi/linux/kexec.h: userspace cannot reference function or variable defined in the kernel
> > > > 
> > > > Signed-off-by: Geoff Levand <geoff@infradead.org>
> > > 
> > > I think Paul Bolle tried to remove this in the past and maximilian
> > > had objections.
> > > 
> > > http://lists.infradead.org/pipermail/kexec/2014-January/010902.html
> > 
> > I've wanted to resend my patch, perhaps with a new commit explanation,
> > for quite some time now. I never got around doing that.
> > 
> > > I can't see that how exporting kernel prototype helps here.
> > 
> > It doesn't, for the reasons I've set out in
> > http://lists.infradead.org/pipermail/kexec/2014-January/010900.html . In
> > short: why bother using this prototype if one still needs to define the
> > matching function oneself?
> > 
> > > kexec-tools
> > > seems to be using syscall(__NR_kexec_load) directly for non-xen case. So
> > > I would be fine with removing this definition. Just trying to make sure
> > > that it does not break any other library or users of this declaration.
> > 
> > Obviously, this can only break compiling those libraries, or other
> > users. It can't break already compiled binaries. Besides I don't think
> > those libraries, etc actually exist. Maximilian mentioned klibc in
> > January, but I wasn't able to find a version of klibc that cared about
> > this prototype. No one pointed me at a version that does (or any other
> > library, etc., for that matter).
> > 
> > (If we do decide to keep this prototype, we should special case this
> > prototype in headers_check.pl just to silence the build.)
> > 
> > The above can be summarized like this:
> >     Acked-by: Paul Bolle <pebolle@tiscali.nl>
> 
> It seems not much happened after I added my Acked-by. I assume you still
> want to get this merged. Is that correct?

Yes, I think we concluded there are no real users of this kexec_load()
ptototype, and so it can be removed.

-Geoff