Couple kernel problems

I've been having a few problems with kernels, and am wondering if these
are known issues.

1) XFS will not load as a module.  When I try I get:
 FATAL: Error inserting xfs
 (/lib/modules/2.6.18-3-parisc/kernel/fs/xfs/xfs.ko):
 Invalid module format

dmesg reveals:
 module xfs relocation of symbol $$divU is out of range (0x3ffefffd in
 17 bits)

This occurs with any kernel I can get from Debian testing and above, so
2.6.17 and 2.6.18.  I tried their images and compiled a 2.6.17 kernel of
my own from their source.  Could this be related to Debian patches?

2) I'm having problems compiling a 2.6.18 kernel (debian source again).
 Perhaps this issue is out-of-scope for this list, but it confuses me
and I wondered if anyone else here has run into it:
 CC      arch/parisc/kernel/asm-offsets.s
   In file included from include/asm/thread_info.h:7,
                    from include/linux/thread_info.h:21,
                    from include/linux/preempt.h:9,
                    from include/linux/spinlock.h:49,
                    from include/linux/capability.h:45,
                    from include/linux/sched.h:44,
                    from arch/parisc/kernel/asm-offsets.c:31:
   include/asm/processor.h:347: error: redefinition of ‘prefetch’
   include/linux/prefetch.h:43: error: previous definition of ‘prefetch’
    was here
   include/asm/processor.h:352: error: redefinition of ‘prefetchw’
   include/linux/prefetch.h:47: error: previous definition of
    ‘prefetchw’ was here

As you can see, it's a simple issue, but what confuses me is that
someone must be compiling this source, since Debian supplies a binary
package in unstable of this kernel.  Could this somehow be related to my
installed tool tree?