Re: cross building linux-image packages
On 1 November 2016 at 10:58, Christian Seiler <christian@iwakd.de> wrote:
> On 11/01/2016 12:22 AM, Andrew Worsley wrote:
>> I tried using pbuilder (based off
>> https://jodal.no/2015/03/08/building-arm-debs-with-pbuilder/) but ->
>> qemu-arm-static has bugs (segmentation faults - possibly
>> https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=811087
>
> You can use (in your pbuilderrc)
> PBUILDERSATISFYDEPENDSCMD="/usr/lib/pbuilder/pbuilder-satisfydepends-classic"
> to make pbuilder use a different (much slower, and in edge cases
> possibly problematic) dependency-resolution algorithm. In that
> case aptitude will never be invoked and builds in qemu-user
> chroots will mostly work - with possibly some exceptions. I've
> never tried a kernel build in such a setup though.
Thank-you very much Christian, that variable does indeed avoid the qemu crash.
I'm hitting other errors now
OS=debian DIST=stretch ARCH=armel pbuilder --build linux_4.7.8-1.dsc
....
-> Considering build-dep gcc-5 [alpha amd64 arm64 armel armhf hppa
i386 m68k mips mipsel mips64 mips64el powerpc powerpcspe ppc64 ppc64el
s390x sh4 sparc64]<!stage1 !cross>
-> Trying gcc-5
-> Considering build-dep gcc-5-alpha-linux-gnu:native [alpha]<!stage1 cross>
-> This package is not for this architecture
-> Considering build-dep gcc-5-x86-64-linux-gnu:native [amd64]<!stage1 cross>
-> This package is not for this architecture
-> Considering build-dep gcc-5-aarch64-linux-gnu:native [arm64]<!stage1 cross>
-> This package is not for this architecture
-> Considering build-dep gcc-5-arm-linux-gnueabi:native [armel]<!stage1 cross>
-> Trying gcc-5-arm-linux-gnueabi:native
-> Cannot install gcc-5-arm-linux-gnueabi:native; apt errors follow:
...
But stretch has gcc-6 ? - anyway much more managable problem than
qemu-arm-static seg fault!
But using a different .dsc file:
OS=debian DIST=stretch ARCH=armel pbuilder --build linux-latest_75.dsc
With this .dsc file It can find gcc-5 ?
Get:35 ftp://218.100.43.30/debian stretch/main armel gcc-5 armel
5.4.1-3 [5297 kB]
I am guessing there is a ton of extra detail to these .dsc files and
kernel building - long learning curve ahead of me but it is actually
BUILDING now!
> Note that qemu-user chroots are _really_, _really_ slow. Builds
> can take anywhere from 3 to 20 times as long as on native
> hardware. (For other packages, in my experience building armhf
> in qemu-user chroots on amd64 is ~12 times slower. YMMV.)
.....
I'll see how far it goes and if my patience will make it.
But as a practical scheme it sounds like I will likely need to go another way.
> Alternatively, you can actually cross-compile stuff by
> employing a real cross compiler that runs natively on your
> hardware (hence faster) but generates code for the target
> hardware you're looking at. The build system of a package must
> support cross compiling explicitly for this to work and be
> useful, I've never tried the kernel packages, so I don't know
> if that will work. You can get a pointer on how to actually
> cross-compile Debian packages under:
> https://wiki.debian.org/CrossCompiling
..
Thanks for this link - it points to schroot - so perhaps that is the
way forward as you suggest it will be *extremely* slow (although for
the small random package appears to be quite practical).
>> But I see that buildd (
>> https://buildd.debian.org/status/logs.php?pkg=linux&arch=armel )
>> apparently works some how.
>
> Well, the official Debian buildds for armhf/armel actually run on
> ARM hardware, so that's why the "work". ;-)
>
> Regards,
> Christian
Ok that explains the current best practices that Debian uses now. I
guess in the past they used schroot.
Thanks again I am so much happier that I have some options to move forwards.
Andrew
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