From: arnd@arndb•de (Arnd Bergmann)
To: linux-arm-kernel@lists•infradead.org
Subject: Building for MMU-less vexpress targets
Date: Tue, 6 Nov 2012 17:33:44 +0000 [thread overview]
Message-ID: <201211061733.44781.arnd@arndb.de> (raw)
In-Reply-To: <20121106122011.GE29853@mudshark.cambridge.arm.com>
On Tuesday 06 November 2012, Will Deacon wrote:
> > ARCH_MULTIPLATFORM
> > bool "Allow multiple platforms to be selected"
> > select ARM_PATCH_PHYS_VIRT if !MMU
> > select AUTO_ZRELADDR if !MMU
>
> you mean if MMU, right?
Yes.
> > but maybe those actually work without MMU as well. I have never looked too
> > closely at NOMMU configurations, every time I tried, they were broken in
> > combination with something else I wanted to enable.
>
> ARM_PATCH_PHYS_VIRT wouldn't make any sense, but I can't see why
> AUTO_ZRELADDR wouldn't be ok.
Ok.
> nommu-XIP kernels are a different kettle
> of fish, but we don't care about a decompressor there.
XIP is only supported on ARCH_PXA and ARCH_SA1100. I don't see either
of them moving to CONFIG_MULTIPLATFORM any time soon, given how much
work that would be. ARCH_MMP should be possible in the future, but
has never supported XIP so far.
> The real problem will hit with things like CONFIG_DRAM_BASE, where !MMU
> can't realistically support multiple platforms, so allowing
> ARCH_MULTIPLATFORM doesn't feel quite right either...
Anybody who wants to build a !MMU kernel already needs to tweak the
configuration quite a lot and usually knows more about the system than
a typical end user. Having to pick the correct DRAM_BASE probably
isn't too bad in that case, as long as the kernels actually build.
Arnd
next prev parent reply other threads:[~2012-11-06 17:33 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 [this message]
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
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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