Lots of x86-64 updates. Merge with 2.4 and NUMA works now. Also reenabled
the preemptive kernel. And some other bug fixes.
IOMMU disabled by default now because it has problems.

 - Add more CONFIG options for device driver debugging and iommu
   force/debug.  (don't enable iommu force currently)
 - Some S3/ACPI fixes/cleanups from Pavel.
 - Set MSG_COMPAT_* in msg_flags for networking 32bit emulation.
   This unfortunately still doesn't fix the fd passing problems.
 - Sync PCI IOMMU code with 2.4 (minor fixes, flush less often)
 - Really fix UP compilation (Pavel)
 - Reenable preempt
 - Fix CONFIG_DISCONTIGMEM bootup and enable.  Still needs more tuning.
 - Fix some bugs in topology discovery and clean code up.
 - Don't put unwind tables into object files
 - Some kernel debugging hooks
 - Move CPU detection into early real mode code to better interact with
   vesafb consoles
 - Initialize mode in real mode character output
 - New 32bit FPU signal save/restore
 - Various fixes in FPU handling in ptrace
 - Fix security holes in ptrace (32bit and 64bit)
 - Fix serial ioctl (including security hole)
 - Add bluetooth ioctls to 32bit emu (from sparc64)
 - Correctly enable si_val in queued signals in 32bit emulation
 - Rework SEM_STAT emulation.  LTP still fails unfortunately.
 - Fix error case in msg* emulation
 - Fix debug register access from ptrace (Michal Ludvig, me)
 - Fix handling of NULL arguments in 32bit execve
 - Fix some error cases for 32bit readv/writev (LTP still complains)
 - Remove rate control from unimplemented syscall warnings
 - Fix error message for missing aperture
 - Turn some APIC printks into Dprintk to make the bootup more quiet
 - Some fixes for no APIC (probably still broken), add disableapic
   option (untested)
 - Sync K8 MCE handler with 2.4.  Should work a lot better now.
 - Remove never used KDB hooks
 - Fix buffer overflow in command line copying
 - Merge from i386: use separate status word for lazy FPU state
 - Don't force the IOMMU for dma masks < 4GB.
 - Print backtrace in Sysrq-T (from Andrea)
 - Merge from i386: fix FPU race in fork.
 - Disable NX mode by default for now
 - Rewrite dump_pagetable
 - Fix off by one bug in ioremap (i386 merge)
 - Merge from i386: handle VIA pci bridge bugs
 - Disable NUMA ACPI support (no SRAT support yet)
 - Fix aio 32bit emulation
 - Increase 32bit address space to nearly 4GB
 - Add exit_group syscall
 - Fix TLS setting in clone (Ulrich Drepper)