From mboxrd@z Thu Jan 1 00:00:00 1970 From: vladimir.murzin@arm.com (Vladimir Murzin) Date: Wed, 7 Dec 2016 14:27:08 +0000 Subject: [PATCH 0/4] arm/versatile: no-MMU support In-Reply-To: <22e20a24-5f1e-a23d-0d18-31dc14179cf5@westnet.com.au> References: <1481090912-29835-1-git-send-email-gerg@uclinux.org> <5847D4F8.1080108@arm.com> <22e20a24-5f1e-a23d-0d18-31dc14179cf5@westnet.com.au> Message-ID: <58481C3C.9090006@arm.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org Hi Greg, On 07/12/16 14:21, Greg Ungerer wrote: > Hi Vladimir, > > On 07/12/16 23:57, Greg Ungerer wrote: >> On 07/12/16 19:23, Vladimir Murzin wrote: >>> On 07/12/16 06:08, Greg Ungerer wrote: >>>> Does the ARM Versatile machine have a maintainer? >>>> I have CC'ed this patch set to those names reported by get_maintainer. >>>> I had no feedback on the first posting of this series back in August. >>>> >>>> The following patches support configuring and building the versatile >>>> machine with a no-MMU kernel. >>>> >>>> There is only a few minor changes required. It was previously possible >>>> in older kernels to build for versatile with CONFIG_MMU disabled, but >>>> the change to devicetree lost that capability. These changes make it >>>> possible again. >>>> >>>> One patch is a fix for address translation (broken in older kernels >>>> too), >>>> two are build problems when CONFIG_MMU is disabled, and the last is the >>>> actuall configuration changes needed. >>>> >>>> The motivation for this is that the versatile machine is well supported >>>> in qemu. And this provides an excellent platform for development and >>>> testing no-MMU support on ARM in general. With these patches applied >>>> it is possible to build and run a kernel with MMU disabled on qemu. >>> >>> I'm wondering if my "Allow NOMMU for MULTIPLATFORM" series [1] work >>> for you? >>> >>> [1] https://www.spinics.net/lists/arm-kernel/msg546823.html >> >> Sorry I hadn't seen these patches before. >> >> Just tried them out. With CONFIG_EXPERT set I can select and >> build for the Versatile machine with CONFIG_MMU not set. The >> build is successful, but the resulting kernel doesn't boot. >> >> I see that the resulting .config has CONFIG_PLAT_VERSATILE set >> but not CONFIG_ARCH_VERSATILE. Is this intentional? > > Let me revise that. By setting the "Multiple platform selection" > selection correctly to v5 platforms I did get CONFIG_ARCH_VERSATILE > set, and could still successfully build the kernel. > > A couple of other config options I had to readjust and I can > boot up this kernel under qemu. So success! > Congrats!!! Thanks for trying these patches! It is really nice to see someone else shows interest on NOMMU! If you don't mind I'll keep you in Cc when/if I re-spin my patches ;) Cheers Vladimir > >> With CONFIG_ARCH_VERSATILE missing the build doesn't traverse >> into arch/arm/mach-versatile, and you don't get any device tree >> built. >> >> Ultimately to produce a working kernel we will still need my >> patch 01/04 ("ARM: versatile: support no-MMU mode addressing"). >> No surprise here, this was missing in older kernels too. > > So in the end this is the only extra change I needed as well > to get the running kernel. > > Regards > Greg > > >