In the timer_interrupt we were not calling set_irq_regs() and if we are
profiling we will end up calling get_irq_regs().  This causes bad things to
happen.
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
 #include <asm/cache.h>
 #include <asm/8xx_immap.h>
 #include <asm/machdep.h>
+#include <asm/irq_regs.h>
 
 #include <asm/time.h>
 
  */
 void timer_interrupt(struct pt_regs * regs)
 {
+       struct pt_regs *old_regs;
        int next_dec;
        unsigned long cpu = smp_processor_id();
        unsigned jiffy_stamp = last_jiffy_stamp(cpu);
        if (atomic_read(&ppc_n_lost_interrupts) != 0)
                do_IRQ(regs);
 
+       old_regs = set_irq_regs(regs);
        irq_enter();
 
        while ((next_dec = tb_ticks_per_jiffy - tb_delta(&jiffy_stamp)) <= 0) {
                ppc_md.heartbeat();
 
        irq_exit();
+       set_irq_regs(old_regs);
 }
 
 /*