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Subject: Re: [RFC PATCH 5/7] powerpc/book3s: Don't turn on the MSR[ME] bit
 until opal processes the reason.
To: Nicholas Piggin <npiggin@gmail.com>
References: <148764180622.19289.14009454092692029974.stgit@jupiter.in.ibm.com>
 <148764197591.19289.17096730042146758117.stgit@jupiter.in.ibm.com>
 <20170221124728.675af9f9@roar.ozlabs.ibm.com>
Cc: linuxppc-dev <linuxppc-dev@ozlabs.org>,
 Benjamin Herrenschmidt <benh@kernel.crashing.org>,
 Paul Mackerras <paulus@samba.org>
From: Mahesh Jagannath Salgaonkar <mahesh@linux.vnet.ibm.com>
Date: Tue, 21 Feb 2017 09:47:53 +0530
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On 02/21/2017 08:17 AM, Nicholas Piggin wrote:
> On Tue, 21 Feb 2017 07:22:56 +0530
> Mahesh J Salgaonkar <mahesh@linux.vnet.ibm.com> wrote:
> 
>> From: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com>
>>
>> Delay it until we are done with machine_check_early() call. Turn on MSR[ME]
>> once opal is done with processing MCE.
> 
> Why? This seems like quite a regression -- the MCE handler today
> has about 60 instructions and 30 l/st with ME clear.

I understand that this is bit long window. But we are in MCE handling
code and if we hit MCE while doing that we may anyway end up with
recursive MCE interrupts without really be able to recover from it.
Instead lets risk checkstop which would get us rebooted with hostboot
throwing proper error call out.

-Mahesh.