Ubuntu 10.10 PPC64

Philipp Kern pkern at ubuntu.com
Tue Nov 9 16:19:27 GMT 2010


Barry,

am Tue, Nov 09, 2010 at 11:11:23AM -0500 hast du folgendes geschrieben:
> On Nov 09, 2010, at 04:57 PM, Philipp Kern wrote:
> >well, the userspace part is 32bit, and some packages wrongly assume a 64bit
> >userland due to the presence of ppc64 in this string.  Hence the requirement
> >to run builds within linux32.  (See personality in schroot.conf for
> >instance.)
> So, the kernel is 64bit but userland is 32bit?  Why is that, and how would you
> know that unless you just knew it? :)

just call `file' on any binary of it and you'll see that it's 32bit.  You want
64bit kernels to e.g. use all the RAM available or to use certain machine
features only available in 64bit mode.  The same reason there's a -amd64 kernel
flavour on i386, at least in Debian.

Other Debian architectures that are similarly affected by this split are sparc
(all current machines are 64bit machines, the userland is sparc32, though) and
s390 (only the 64-bit s390x kernels still have upstream support). 

Mainly the machines and kernels went 64bit and the userland was stuck in 32bit
because nobody did another entirely new port.  And on some architectures you're
not as register-constrained as on x86 so 64bit userlands might only be bigger
in memory and cache and not more useful.

> My schroot.conf on that machine had no personality set, but I've gone ahead
> and added linux32 to all three distroseries.  I don't need to do any kind of
> updates for those chroots, do I?

Nope.  In Debian we also remove libc6-ppc64 from the chroots which is the 64bit
C runtime.  Packages that need it should build-depend on gcc-multilib.

Hope that helps,
Philipp Kern
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