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From: Nicholas Piggin <npiggin@gmail.com>
To: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: linuxppc-dev@lists.ozlabs.org, skiboot@lists.ozlabs.org,
	Alistair Popple <alistair@popple.id.au>
Subject: Re: [RFC PATCH 2/2] powerpc/powernv: implement NMI IPIs with OPAL_SIGNAL_SYSTEM_RESET
Date: Thu, 14 Sep 2017 16:32:28 +1000	[thread overview]
Message-ID: <20170914163228.0510251a@roar.ozlabs.ibm.com> (raw)
In-Reply-To: <1505355889.12628.177.camel@kernel.crashing.org>

On Thu, 14 Sep 2017 12:24:49 +1000
Benjamin Herrenschmidt <benh@kernel.crashing.org> wrote:

> On Wed, 2017-09-13 at 23:13 +1000, Nicholas Piggin wrote:
> > On Wed, 13 Sep 2017 02:05:53 +1000
> > Nicholas Piggin <npiggin@gmail.com> wrote:
> >   
> > > There are two complications. The first is that sreset from stop states
> > > come in with SRR1 set to do a powersave wakeup, with an sreset reason
> > > encoded.
> > > 
> > > The second is that threads on the same core can't be signalled directly
> > > so we must designate a bounce CPU to reflect the IPI back.  
> > 
> > Here is an updated Linux patch for the latest OPAL patch. This has
> > a few assorted fixes as well to make it work nicely, I roll them into
> > one patch here to make it easy to apply for testing the OPAL patch.  
> 
> Why can't you sreset threads of the same core on P9 ?

It looks like we can, I think I had some other bugs still not ironed
out when I previously tested it.

That simplifies things a lot on the Linux side. It may be that the
bounce is still required if we implement it on POWER8 using ramming,
but I'll get the POWER9 code in first.

Thanks,
Nick

  reply	other threads:[~2017-09-14  6:32 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-09-12 16:05 [RFC PATCH 0/2] NMI IPI work in progress for Linux and OPAL Nicholas Piggin
2017-09-12 16:05 ` [RFC PATCH 1/2] core: implement OPAL_SIGNAL_SYSTEM_RESET with POWER9 scoms Nicholas Piggin
2017-09-12 23:18   ` Benjamin Herrenschmidt
2017-09-13 13:27     ` Nicholas Piggin
2017-09-14  2:27       ` Benjamin Herrenschmidt
2017-09-12 16:05 ` [RFC PATCH 2/2] powerpc/powernv: implement NMI IPIs with OPAL_SIGNAL_SYSTEM_RESET Nicholas Piggin
2017-09-13 13:13   ` Nicholas Piggin
2017-09-14  2:24     ` Benjamin Herrenschmidt
2017-09-14  6:32       ` Nicholas Piggin [this message]
2017-09-14  6:43         ` Alistair Popple
2017-09-14 11:26   ` Nicholas Piggin

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