Locking was added where necessary.
All processors take timer interrupts, but only CPU 0 calls the timer
IRQ.  The others just call update_process_times to keep the
accounting straight.
The timer interrupt is blocked along with the other signals.

The tempfile code is in its own file.
A bunch of unused stuff is now gone.
A bunch of code that could be called from the tracing thread was
made safe for that to happen.

Fixed a process exit bug.

The UML initialization code marks memory that doesn't fit in the
kernel's address space as highmem, and later sets up the UML data
structures for it, and frees that memory to the mm system as highmem.

Fixed the net crash seen when slab debugging is enabled
Fixed PROT_NONE
Fixed the 'tracing myself' bug seen on umlcoop.  This was caused by
a number of SIGALRM handlers nesting on the idle thread stack because
the system was busy enough that UML couldn't clear one before the
next arrived.

This patch implements UML for 2.5.34.