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From: Michael Ellerman <mpe@ellerman.id.au>
To: Paul Mackerras <paulus@ozlabs.org>
Cc: Leonardo Bras <leonardo@linux.ibm.com>,
	Nicholas Piggin <npiggin@gmail.com>,
	Alexios Zavras <alexios.zavras@intel.com>,
	Benjamin Herrenschmidt <benh@kernel.crashing.org>,
	Christophe Leroy <christophe.leroy@c-s.fr>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Enrico Weigelt <info@metux.net>,
	peterz@infradead.org, Thomas Gleixner <tglx@linutronix.de>,
	linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org
Subject: Re: [PATCH v3 1/1] ppc/crash: Reset spinlocks during crash
Date: Tue, 12 May 2020 20:42:21 +1000	[thread overview]
Message-ID: <87mu6dbfjm.fsf@mpe.ellerman.id.au> (raw)
In-Reply-To: <20200409002726.GA5135@blackberry>

Paul Mackerras <paulus@ozlabs.org> writes:
> 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 only
>> ~80 odd bytes. And then we can use rtas_call_unlocked() which doesn't
>> take the global lock.
>
> Do we instantiate a 64-bit RTAS these days, or is it still 32-bit?

No, yes.

> In the old days we had to make sure the RTAS argument buffer was
> below the 4GB point.

Yes you're right, that's still true.

I was thinking we were on the emergency stack, but we may not be.

> If that's still necessary then perhaps putting rtas_args inside the
> PACA would be the way to go.

Yeah I guess. Allocating a struct within the RMO for each CPU is not
that simple vs just putting it in the paca.

cheers

  parent reply	other threads:[~2020-05-12 10:42 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-04-01  0:00 [PATCH v3 1/1] ppc/crash: Reset spinlocks during crash Leonardo Bras
2020-04-01  3:07 ` kbuild test robot
2020-04-01  9:26 ` Peter Zijlstra
2020-04-01 23:53   ` Leonardo Bras
2020-04-02 11:28 ` Michael Ellerman
2020-04-03  0:37   ` Leonardo Bras
2020-04-03  6:41     ` Nicholas Piggin
2020-04-08  2:36       ` Leonardo Bras
2020-04-08 12:21         ` Michael Ellerman
2020-04-08 16:48           ` Leonardo Bras
2020-04-08 18:00           ` Leonardo Bras
2020-04-08 22:55           ` Leonardo Bras
2020-04-09  0:27           ` Paul Mackerras
2020-05-12  3:48             ` Leonardo Bras
2020-05-12 10:42             ` Michael Ellerman [this message]
2020-04-06 18:46   ` Leonardo Bras

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