linux-kernel - Re: [PATCH 22/25] x86/mcheck: Do the init in one place

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Date:   Thu, 10 Nov 2016 10:18:09 +0100
From:   Borislav Petkov <bp@...en8.de>
To:     Sebastian Andrzej Siewior <bigeasy@...utronix.de>
Cc:     "Luck, Tony" <tony.luck@...el.com>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "rt@...utronix.de" <rt@...utronix.de>,
        "linux-edac@...r.kernel.org" <linux-edac@...r.kernel.org>,
        "x86@...nel.org" <x86@...nel.org>,
        Thomas Gleixner <tglx@...utronix.de>
Subject: Re: [PATCH 22/25] x86/mcheck: Do the init in one place

On Thu, Nov 10, 2016 at 10:00:38AM +0100, Sebastian Andrzej Siewior wrote:
> okay. So I had a discussion with Boris and we agreed that we don't do
> the init part in one place only the timer stuff will be moved.
> If I understand Tony correctly then we undo something in
> vendor_disable_error_reporting() (on !INTEL CPUs) that we enable in
> identify_cpu().
> 
> Boris, if my understanding is correct, what now? Do move the whole
> hotplug init part to an earlier stage? Or do we drop
> vendor_disable_error_reporting()?

Nah, we proceed as we discussed it - let's move the timer only. The
mce_gen_pool_init() allocation is not where it should be - it should
run somewhere only once on CPU0 but I haven't found a better place yet
so that the allocation succeeds - mind you, this is very early and
gen_pool_create() uses kmalloc_node() which might not be functioning
yet...

Tony's point is showing that the hotplug notifiers don't do any
bit clearing on Intel, i.e., basically we don't do anything on the
CPU_DOWN_PREPARE path on Intel.

Thanks.

-- 
Regards/Gruss,
    Boris.

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