From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <linux-kernel-owner@vger.kernel.org>
Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand
        id S965009AbdCJN55 (ORCPT <rfc822;w@1wt.eu>);
        Fri, 10 Mar 2017 08:57:57 -0500
Received: from Galois.linutronix.de ([146.0.238.70]:56576 "EHLO
        Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org
        with ESMTP id S934105AbdCJN5z (ORCPT
        <rfc822;linux-kernel@vger.kernel.org>);
        Fri, 10 Mar 2017 08:57:55 -0500
Date: Fri, 10 Mar 2017 14:57:38 +0100 (CET)
From: Thomas Gleixner <tglx@linutronix.de>
To: Mike Galbraith <efault@gmx.de>
cc: Borislav Petkov <bp@alien8.de>, "Tobin C. Harding" <me@tobin.cc>,
        LKML <linux-kernel@vger.kernel.org>,
        Nicholas Mc Guire <der.herr@hofr.at>, Vivek Goyal <vgoyal@redhat.com>,
        x86@kernel.org
Subject: Re: kexec, x86/purgatory: Cleanup the unholy mess
In-Reply-To: <1489153665.4410.4.camel@gmx.de>
Message-ID: <alpine.DEB.2.20.1703101457160.3681@nanos>
References: <alpine.DEB.2.20.1703101315140.3681@nanos> <1489153665.4410.4.camel@gmx.de>
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

On Fri, 10 Mar 2017, Mike Galbraith wrote:
> On Fri, 2017-03-10 at 13:17 +0100, Thomas Gleixner wrote:
> > The purgatory code defines global variables which are referenced via a
> > symbol lookup in the kexec code (core and arch).
> > 
> > A recent commit addressing sparse warning made these static and thereby
> > broke kexec file.
> > 
> > Why did this happen? Simply because the whole machinery is undocumented and
> > lacks any form of forward declarations. The variable names are unspecific
> > and lack a prefix, so adding forward declarations creates shadow variables
> > in the core code. Aside of that the code relies on magic constants and
> > duplicate struct definitions with no way to ensure that these things stay
> > in sync.
> > 
> > Unbreak kexec and cleanup the mess by:
> > 
> >  - Adding proper forward declarations and document the usage
> >  - Use the proper common defines instead of magic constants
> >  - Add a purgatory_ prefix to have a proper name space
> >  - Use ARRAY_SIZE() instead of a homebrewn reimplementation
> > 
> > Fixes: 72042a8c7b01 ("x86/purgatory: Make functions and variables static")
> 
> Well, almost fixes.
> 
> [   15.118820] kexec: symbol 'purgatory_sha_regions' in common section
> [   15.119187] kexec-bzImage64: Loading purgatory failed

Bah. /me goes to investigate.