linux-kernel - Re: [PATCH 5/5] x86, AMD: simplify load_microcode_amd() to fix early microcode loading to no longer access uninitialized per-cpu data

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Message-ID: <20130724193250.GO30777@pd.tnic>
Date:	Wed, 24 Jul 2013 21:32:50 +0200
From:	Borislav Petkov <bp@...en8.de>
To:	Torsten Kaiser <just.for.lkml@...glemail.com>
Cc:	Thomas Gleixner <tglx@...utronix.de>,
	Ingo Molnar <mingo@...hat.com>,
	"H. Peter Anvin" <hpa@...or.com>, Jacob Shin <jacob.shin@....com>,
	Johannes Hirte <johannes.hirte@....tu-ilmenau.de>,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH 5/5] x86, AMD: simplify load_microcode_amd() to fix early
 microcode loading to no longer access uninitialized per-cpu data

On Tue, Jul 23, 2013 at 11:06:10PM +0200, Torsten Kaiser wrote:
> load_microcode_amd() (and the helper it is using) should not have an
> cpu parameter. The microcode loading is not depending on the CPU it is
> executed and all the loaded patches will end up in a global list for all
> CPUs anyway.
> The change from cpu to x86family in load_microcode_amd() now allows to drop
> the code messing with cpu_data(cpu) from collect_cpu_info_amd_early(), which 
> is wrong anyway because at that point the per-cpu cpu_info is not yet setup. 
> And these values would later be overwritten by smp_store_boot_cpu_info() / 
> smp_store_cpu_info().
> 
> Fold the rest of collect_cpu_info_amd_early() into load_ucode_amd_ap(), because its
> only used at one place and without the cpuinfo_x86 accesses it was not much left.
> 
> Signed-off-by: Torsten Kaiser <just.for.lkml@...glemail.com>

Btw, this patch is the one that fixes the boot issue on your box, correct?

If so, please put a minimal version of it in the next patch set you're
sending right after

[PATCH v2] x86, AMD: Make cpu_has_amd_erratum() use the correct struct cpuinfo_x86
[PATCH 1/5] x86, AMD: fix error path in apply_microcode_amd()

So that all fixes can go in now.

Basically, we need the fixes to be first in the patchset so that they
can be applied straight to tip:urgent.

The cleanups/improvements you're doing afterwards could wait then for
the next merge window.

Thanks a lot!

-- 
Regards/Gruss,
    Boris.

Sent from a fat crate under my desk. Formatting is fine.
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