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From:   Dan Williams <dan.j.williams@intel.com>
Date:   Wed, 7 Oct 2020 11:53:15 -0700
Message-ID: <CAPcyv4jgLRzDzXkbdHwA-XUwWuSoA1tZfVqgvFQ5jxq=m2P_Bg@mail.gmail.com>
Subject: Re: [tip: ras/core] x86, powerpc: Rename memcpy_mcsafe() to
 copy_mc_to_{user, kernel}()
To:     Borislav Petkov <bp@alien8.de>
Cc:     linux-tip-commits@vger.kernel.org, Tony Luck <tony.luck@intel.com>,
        Michael Ellerman <mpe@ellerman.id.au>,
        stable <stable@vger.kernel.org>, x86 <x86@kernel.org>,
        LKML <linux-kernel@vger.kernel.org>
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On Wed, Oct 7, 2020 at 11:47 AM Borislav Petkov <bp@alien8.de> wrote:
>
> On Wed, Oct 07, 2020 at 06:45:36PM +0200, Borislav Petkov wrote:
> > It doesn't look like it is toolchain-specific and in both cases,
> > copy_mc_fragile's checksum is 0.
> >
> > SUSE Leap 15.1:
> >
> > Name           : binutils
> > Version        : 2.32-lp151.3.6.1
> >
> > $ grep -E "(copy_mc_fragile|copy_user_generic_unrolled)" Module.symvers
> > 0x00000000      copy_mc_fragile vmlinux EXPORT_SYMBOL_GPL
> > 0xecdcabd2      copy_user_generic_unrolled      vmlinux EXPORT_SYMBOL
> >
> > debian testing:
> >
> > Package: binutils
> > Version: 2.35-2
> >
> > $ grep -E "(copy_mc_fragile|copy_user_generic_unrolled)" Module.symvers
> > 0x00000000      copy_mc_fragile vmlinux EXPORT_SYMBOL_GPL
> > 0xecdcabd2      copy_user_generic_unrolled      vmlinux EXPORT_SYMBOL
>
> Ok, I think I have it:
>
> ---
> From: Borislav Petkov <bp@suse.de>
> Date: Wed, 7 Oct 2020 18:55:35 +0200
> Subject: [PATCH] x86/mce: Allow for copy_mc_fragile symbol checksum to be generated
>
> Add asm/mce.h to asm/asm-prototypes.h so that that asm symbol's checksum
> can be generated in order to support CONFIG_MODVERSIONS with it and fix:
>
>   WARNING: modpost: EXPORT symbol "copy_mc_fragile" [vmlinux] version \
>           generation failed, symbol will not be versioned.
>
> For reference see:
>
>   4efca4ed05cb ("kbuild: modversions for EXPORT_SYMBOL() for asm")
>   334bb7738764 ("x86/kbuild: enable modversions for symbols exported from asm")

Oh nice! I just sent a patch [1] to fix this up as well, but mine goes
after minimizing when it is exported, I think perhaps both are needed.

http://lore.kernel.org/r/160209507277.2768223.9933672492157583642.stgit@dwillia2-desk3.amr.corp.intel.com