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Groups > linux.kernel > #1597710

Re: kexec, x86/purgatory: Cleanup the unholy mess

From Thomas Gleixner <tglx@linutronix.de>
Newsgroups linux.kernel
Subject Re: kexec, x86/purgatory: Cleanup the unholy mess
Date 2017-03-10 15:00 +0100
Message-ID <tjtfl-4NB-49@gated-at.bofh.it> (permalink)
References <tjrGA-3S0-97@gated-at.bofh.it> <tjt5F-4JP-49@gated-at.bofh.it>
Organization linux.* mail to news gateway

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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.

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Thread

kexec, x86/purgatory: Cleanup the unholy mess Thomas Gleixner <tglx@linutronix.de> - 2017-03-10 13:20 +0100
  Re: kexec, x86/purgatory: Cleanup the unholy mess Mike Galbraith <efault@gmx.de> - 2017-03-10 14:50 +0100
    Re: kexec, x86/purgatory: Cleanup the unholy mess Thomas Gleixner <tglx@linutronix.de> - 2017-03-10 15:00 +0100
      Re: kexec, x86/purgatory: Cleanup the unholy mess Vivek Goyal <vgoyal@redhat.com> - 2017-03-10 15:30 +0100
        Re: kexec, x86/purgatory: Cleanup the unholy mess Thomas Gleixner <tglx@linutronix.de> - 2017-03-10 16:00 +0100
          Re: kexec, x86/purgatory: Cleanup the unholy mess Vivek Goyal <vgoyal@redhat.com> - 2017-03-10 16:10 +0100
      Re: kexec, x86/purgatory: Cleanup the unholy mess Mike Galbraith <efault@gmx.de> - 2017-03-10 15:40 +0100
        Re: kexec, x86/purgatory: Cleanup the unholy mess Mike Galbraith <efault@gmx.de> - 2017-03-10 16:00 +0100
          Re: kexec, x86/purgatory: Cleanup the unholy mess Thomas Gleixner <tglx@linutronix.de> - 2017-03-10 16:40 +0100
            Re: kexec, x86/purgatory: Cleanup the unholy mess Mike Galbraith <efault@gmx.de> - 2017-03-10 19:20 +0100
        Re: kexec, x86/purgatory: Cleanup the unholy mess Thomas Gleixner <tglx@linutronix.de> - 2017-03-10 16:00 +0100
  [tip:x86/urgent] kexec, x86/purgatory: Unbreak it and clean it up tip-bot for Thomas Gleixner <tipbot@zytor.com> - 2017-03-10 21:20 +0100

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