From: Nicholas Piggin <npiggin@gmail.com>
To: Mahesh Jagannath Salgaonkar <mahesh@linux.vnet.ibm.com>
Cc: linuxppc-dev <linuxppc-dev@ozlabs.org>,
Benjamin Herrenschmidt <benh@kernel.crashing.org>,
Paul Mackerras <paulus@samba.org>
Subject: Re: [RFC PATCH 5/7] powerpc/book3s: Don't turn on the MSR[ME] bit until opal processes the reason.
Date: Tue, 21 Feb 2017 14:43:40 +1000 [thread overview]
Message-ID: <20170221144340.3f784ff3@roar.ozlabs.ibm.com> (raw)
In-Reply-To: <c3a85fbf-29e8-e20d-dc68-6c1f1413d063@linux.vnet.ibm.com>
On Tue, 21 Feb 2017 09:47:53 +0530
Mahesh Jagannath Salgaonkar <mahesh@linux.vnet.ibm.com> wrote:
> 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.
There is careful code to handle recursive machine checks though.
Things should be structured so we will handle recursive MCEs and
recover/fail/checkstop properly.
> Instead lets risk checkstop which would get us rebooted with hostboot
> throwing proper error call out.
I'd like more justification for the proposed change. How is it an
improvement?
Thanks,
Nick
next prev parent reply other threads:[~2017-02-21 4:43 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-02-21 1:51 [RFC PATCH 0/7] Machine check handling for Power9 with bacward compatibility Mahesh J Salgaonkar
2017-02-21 1:51 ` [RFC PATCH 1/7] powerpc/book3s: Move machine check event structure to opal-api.h Mahesh J Salgaonkar
2017-02-21 2:35 ` Nicholas Piggin
2017-02-21 6:51 ` Mahesh Jagannath Salgaonkar
2017-02-21 1:52 ` [RFC PATCH 2/7] powerpc/book3s: mce: Call opal mce handler to extract MCE error reason Mahesh J Salgaonkar
2017-02-21 1:52 ` [RFC PATCH 3/7] powerpc/book3s: mce: Process the MCE event and recover if possible Mahesh J Salgaonkar
2017-02-21 1:52 ` [RFC PATCH 4/7] powerpc/book3s: Print additional MCE errors introduced in power9 Mahesh J Salgaonkar
2017-02-21 1:52 ` [RFC PATCH 5/7] powerpc/book3s: Don't turn on the MSR[ME] bit until opal processes the reason Mahesh J Salgaonkar
2017-02-21 2:47 ` Nicholas Piggin
2017-02-21 4:17 ` Mahesh Jagannath Salgaonkar
2017-02-21 4:43 ` Nicholas Piggin [this message]
2017-02-21 1:53 ` [RFC PATCH 6/7] powerpc/book3s: Display more info for MCE error console log Mahesh J Salgaonkar
2017-02-21 1:53 ` [RFC PATCH 7/7] powerpc/book3s: Display task info for MCE error in user mode Mahesh J Salgaonkar
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