Date: Fri, 7 Apr 2006 21:38:19 +0800 From: Astrodog <astrodog@gmail.com> To: "Danny Braniss" <danny@cs.huji.ac.il> Cc: freebsd-amd64@freebsd.org Subject: Re: safe way to build i386 arch makeworld on amd64 arch? Message-ID: <2fd864e0604070638n11ff30f1pa9ad3fe5ac669ea7@mail.gmail.com> In-Reply-To: <E1FRohf-000B4K-BW@cs1.cs.huji.ac.il> References: <patrick@cyberwizards.nl> <20060407114033.J30882@gandalf.cyberwizards.nl> <E1FRohf-000B4K-BW@cs1.cs.huji.ac.il>
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On 4/7/06, Danny Braniss <danny@cs.huji.ac.il> wrote: > > hello list, > > > > is there a save way to 'downgrade' an amd64 build system by using 'make= world' ? > > > > e.g. just remove the CPUTYPE=3Dopteron from the make.conf file and do a > > build world/kernels install world/kernels ? > > > > of do we need to do some more for this? > > > > thanks in advance > > > > Regards > > patrick > > To downgrade? Not realistically. > you can, i do: > export MAKEOBJDIRPREFIX=3D/somwhersafe-i386 > make TARGET_ARCH=3Di386 buildworld > same for buildkernel, installworld/installkernel, and also you can specif= y > a different DESTDIR=3D > > danny > That would certainly allow him to crosscompile an i386 kernel, and world, but wouldn't have much effect on downgrading from AMD64 to i386, since you run into a chicken or the egg problem with the kernel, and world. (a 64-bit kernel does not play nice on a 32-bit world, without some hacking around, and a 32-bit kernel does not play nice on a 64-bit world), which makes it impossible to actually do both steps. If you install the 32-bit kernel first, and reboot, the kernel won't be able to run the 64-bit binaries. If you install the 32-bit world first, the 64-bit kernel will become very, very sad, and won't let the installation complete. If you try to install the kernel, then the world without a reboot, you have the same problem as installing the 32-bit world first, since even with a 32-bit kernel installed, you're still RUNNING the 64-bit kernel until you reboot. There are actually ways to do this, but its almost always a bad idea. Not to mention this will break any packages, or ports you're using too, with the exception, perhaps, of Linux Compat.
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