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From: Segher Boessenkool <segher@kernel.crashing.org>
To: Christophe Leroy <christophe.leroy@c-s.fr>
Cc: "linuxppc-dev@ozlabs.org" <linuxppc-dev@ozlabs.org>,
	Paul Mackerras <paulus@samba.org>,
	Nicholas Piggin <npiggin@gmail.com>
Subject: Re: What is CONFIG_RTAS ? Which CPUs are concerned
Date: Mon, 28 Jan 2019 12:32:32 -0600	[thread overview]
Message-ID: <20190128183231.GP14180@gate.crashing.org> (raw)
In-Reply-To: <e8b0ddb9-cfe9-af20-03b1-4036a843cdc7@c-s.fr>

On Mon, Jan 28, 2019 at 07:20:43PM +0100, Christophe Leroy wrote:
> I'm wondering what CONFIG_RTAS is. It makes use of one of the SPRN_SPRG, 
> ie SPRN_SPRG2.
> 
> What are the CPUs concerned by RTAS ? Is there any of the old CPUs which 
> have only 4 SPRGs (eg the 601), or could we use one in SPRG4-7 for it 
> and reuse SPRG2 for something else ?

RTAS (run-time abstraction services) is as old as PowerPC itself.  Yes there
is RTAS on various 6xx, and those do not have any SPRGs not defined in the
architecture.

RTAS is a feature of the firmware, or of the platform you could say.  Not a
feature of CPUs.


Segher

      reply	other threads:[~2019-01-28 18:36 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-01-28 18:20 What is CONFIG_RTAS ? Which CPUs are concerned Christophe Leroy
2019-01-28 18:32 ` Segher Boessenkool [this message]

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