diff -urpN linux-2.6.19-rc2.orig/arch/ppc/kernel/time.c linux-2.6.19-rc2/arch/ppc/kernel/time.c
--- linux-2.6.19-rc2.orig/arch/ppc/kernel/time.c	2006-10-16 21:05:52.000000000 +0200
+++ linux-2.6.19-rc2/arch/ppc/kernel/time.c	2006-10-16 21:12:42.000000000 +0200
@@ -56,6 +56,7 @@
 #include <linux/time.h>
 #include <linux/init.h>
 #include <linux/profile.h>
+#include <linux/irq.h>
 
 #include <asm/io.h>
 #include <asm/nvram.h>
@@ -129,6 +130,7 @@ void wakeup_decrementer(void)
  */
 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);
@@ -137,6 +139,7 @@ void timer_interrupt(struct pt_regs * re
 	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) {
@@ -188,6 +191,7 @@ void timer_interrupt(struct pt_regs * re
 		ppc_md.heartbeat();
 
 	irq_exit();
+	set_irq_regs(old_regs);
 }
 
 /*