From: arnd@arndb•de (Arnd Bergmann)
To: linux-arm-kernel@lists•infradead.org
Subject: Building for MMU-less vexpress targets
Date: Wed, 7 Nov 2012 13:29:26 +0000 [thread overview]
Message-ID: <201211071329.26995.arnd@arndb.de> (raw)
In-Reply-To: <alpine.LFD.2.02.1211061802240.21033@xanadu.home>
On Tuesday 06 November 2012, Nicolas Pitre wrote:
> On Tue, 6 Nov 2012, Arnd Bergmann wrote:
>
> > On Tuesday 06 November 2012, Nicolas Pitre wrote:
> > > I really think that it makes no sense at all to support !MMU kernels in
> > > a multi-platform kernel build, even if the set of included platforms
> > > were all !MMU. The kernel has to be linked for the physical address of
> > > the target and not a common invariant virtual address.
> >
> > There are two separate aspects here: One is to run a kernel on !MMU that is
> > built to support multiple platforms. I agree that this is rather pointless
> > and not interesting.
> >
> > The other point is being able to build such a kernel, and this is what Will
> > seems to be interested in more.
>
> What's the point of building a pointless and uninteresting kernel?
Built-time coverage is the only one I can think of, but I think it's a
good reason. Being able to build an "allyesconfig" with MMU disabled
sounds like a good sniff test to see if something broke and is much faster
than building all the defconfigs.
> > The two options are either to make
> > vexpress be single-platform when building for !MMU, or to allow multiplatform
> > kernels to be built without MMU support in principle. I think the second
> > option is more logical and avoids complex Kconfig constructs.
>
> Well, I'd rather prefer to think that the first option is the most
> logical between those 2 options, regardless of Kconfig complexity
> issues.
>
> I didn't look, but just making MULTIPLATFORM depend on !MMU, and
> VEXPRESS depend on MULTIPLATFORM || MMU should be close to what is
> needed, no?
Fine with me too. I suppose you just made the same logic error that
I had earlier in this thread and meant !MMU where you wrote MMU.
Arnd
next prev parent reply other threads:[~2012-11-07 13:29 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-11-05 17:36 Building for MMU-less vexpress targets Will Deacon
2012-11-05 18:03 ` Pawel Moll
2012-11-05 18:13 ` Will Deacon
2012-11-05 19:08 ` Arnd Bergmann
2012-11-06 12:20 ` Will Deacon
2012-11-06 17:33 ` Arnd Bergmann
2012-11-06 18:34 ` Will Deacon
2012-11-06 20:35 ` Arnd Bergmann
2012-11-06 20:58 ` Nicolas Pitre
2012-11-06 21:14 ` Arnd Bergmann
2012-11-06 22:14 ` Russell King - ARM Linux
2012-11-06 22:59 ` Rob Herring
2012-11-07 12:59 ` Arnd Bergmann
2012-11-07 13:39 ` Russell King - ARM Linux
2012-11-06 23:14 ` Nicolas Pitre
2012-11-07 10:21 ` Will Deacon
2012-11-07 13:29 ` Arnd Bergmann [this message]
2013-01-08 19:01 ` Jonathan Austin
2013-01-08 19:11 ` Arnd Bergmann
2013-01-08 19:22 ` Nicolas Pitre
2012-11-06 22:51 ` Jamie Lokier
2012-11-06 23:40 ` Nicolas Pitre
2012-11-06 23:46 ` Jamie Lokier
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