This patch fixes up ia64 kexec support for HP rx2620 hardware.  It does
this by skipping migration of already disabled irqs.  This is most likely a
problem on other ia64 platforms as well, but I've only been able to
reproduce it on one machine so far.

The full story is that handle_bad_irq() gets invoked before starting the
new kernel without this patch.  This seems to happen when fixup_irqs()
calls generic_handle_irq() on already migrated (and disabled) irqs.  So by
avoiding migration of disabled irqs we stay away of handle_bad_irq().

The code has been tested on three different ia64 machines, all with good
results.  It is possible to trigger the same bug by offlining a processor
using echo 0 > /sys/devices/system/cpu/cpuX/online.

More detailed information is available in the following mail thread:
http://lists.osdl.org/pipermail/fastboot/2007-January/thread.html#5774



Signed-off-by: Magnus Damm <magnus@valinux.co.jp>
Acked-by: Simon Horman <horms@verge.net.au>
Acked-by: Zou, Nanhai <nanhai.zou@intel.com>
Acked-by: Jay Lan <jlan@sgi.com>
Acked-by: "Luck, Tony" <tony.luck@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>