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Subject: Re: [PATCH] powerpc: module: fix TOC symbol CRC
From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
To: Anton Blanchard <anton@samba.org>
Date: Tue, 24 Jun 2014 14:06:10 +1000
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Cc: rusty@rustcorp.com.au, Laurent Dufour <ldufour@linux.vnet.ibm.com>,
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On Thu, 2014-06-19 at 09:44 +1000, Anton Blanchard wrote:
> Hi Laurent,
> 
> > The commit 71ec7c55ed91 introduced the magic symbol ".TOC." for ELFv2
> > ABI. This symbol is built manually and has no CRC value computed. A
> > zero value is put in the CRC section to avoid modpost complaining
> > about a missing CRC. Unfortunately, this breaks the kernel module
> > loading when the kernel is relocated (kdump case for instance)
> > because of the relocation applied to the kcrctab values.
> > 
> > This patch compute a CRC value for the TOC symbol which will match
> > the one compute by the kernel when it is relocated - aka '0 -
> > relocate_start' done in maybe_relocated called by check_version
> > (module.c).
> 
> Adding Rusty since he maintains the module loader code.

This patch gives me:

arch/powerpc/kernel/module_64.c: In function 'dedotify_versions':
arch/powerpc/kernel/module_64.c:325:33: error: 'reloc_start' undeclared (first use in this function)
arch/powerpc/kernel/module_64.c:325:33: note: each undeclared identifier is reported only once for each function it appears in

Cheers,
Ben.