Bug#414932: Info received (Bug#414932: linux-image-2.6.18-4-ixp4xx: xfs partition from x86 system can not be used on arm)

[Lennert Buytenhek <buytenh@wantstofly.org>]

On Thu, Apr 26, 2007 at 11:57:40PM -0500, Eric Sandeen wrote:

> Maybe the alignment isn't broken; it's just "special" - I guess there 
> are no actual rules on how the structure must be aligned...  hmm...

Yep.  Padding rules on old-ABI ARM systems are 'special', but still
spec-compliant.  See:

	http://www.simplemachines.it/arm-linux/book/afaq.html

For example, this means that sizeof(struct { char a; char b; }) == 4
on old-ABI ARM systems.  This is the main cause of pain when porting
applications to ARM platforms.  (#2 is the fact that chars are unsigned
by default on ARM, which is also something that the relevant specs
allow but not a lot of people expect.)

The new ARM ABI (EABI) changes both of these things (and a couple more,
such as 64 bit type alignment and the floating point calling convention)
to be more in line with other deployed Linux platforms.  There is a
preliminary Debian EABI port available here:

	http://wiki.debian.org/ArmEabiPort

But Debian EABI uptake has been very slow, and most people are still on
old-ABI systems.