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Subject: Re: [PATCH v3 1/1] ppc/crash: Reset spinlocks during crash
From:   Leonardo Bras <leobras.c@gmail.com>
To:     Paul Mackerras <paulus@ozlabs.org>,
        Michael Ellerman <mpe@ellerman.id.au>
Cc:     peterz@infradead.org, linuxppc-dev@lists.ozlabs.org,
        linux-kernel@vger.kernel.org, Nicholas Piggin <npiggin@gmail.com>,
        Alexios Zavras <alexios.zavras@intel.com>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Thomas Gleixner <tglx@linutronix.de>,
        Enrico Weigelt <info@metux.net>
Date:   Tue, 12 May 2020 00:48:28 -0300
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Hello Paul, thanks for the reply!

On Thu, 2020-04-09 at 10:27 +1000, Paul Mackerras wrote:
> On Wed, Apr 08, 2020 at 10:21:29PM +1000, Michael Ellerman wrote:
> > We should be able to just allocate the rtas_args on the stack, it's onl=
y
> > ~80 odd bytes. And then we can use rtas_call_unlocked() which doesn't
> > take the global lock.
>=20
> Do we instantiate a 64-bit RTAS these days, or is it still 32-bit?

According to LoPAR, we can use instantiate-rtas or instantiate-rtas-64.=20
It looks like we do instantiate-rtas today (grep pointed only to
prom_instantiate_rtas()).

> In the old days we had to make sure the RTAS argument buffer was
> below the 4GB point.  If that's still necessary then perhaps putting
> rtas_args inside the PACA would be the way to go.

Yes, we still need to make sure of this. I will study more about PACA
and try to implement that way.

Best regards,
Leonardo Bras

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