diff --git a/arch/s390/include/asm/idle.h b/arch/s390/include/asm/idle.h
index 113cd963dbbe..51ff96d9f287 100644
--- a/arch/s390/include/asm/idle.h
+++ b/arch/s390/include/asm/idle.h
@@ -24,4 +24,6 @@ struct s390_idle_data {
 extern struct device_attribute dev_attr_idle_count;
 extern struct device_attribute dev_attr_idle_time_us;
 
+void psw_idle(struct s390_idle_data *, unsigned long);
+
 #endif /* _S390_IDLE_H */
diff --git a/arch/s390/include/asm/irq.h b/arch/s390/include/asm/irq.h
index ff95d15a2384..33d26424c2f5 100644
--- a/arch/s390/include/asm/irq.h
+++ b/arch/s390/include/asm/irq.h
@@ -96,6 +96,19 @@ enum irq_subclass {
 	IRQ_SUBCLASS_SERVICE_SIGNAL = 9,
 };
 
+#define CR0_IRQ_SUBCLASS_MASK					  \
+	((1UL << (63 - 30))  /* Warning Track */		| \
+	 (1UL << (63 - 48))  /* Malfunction Alert */		| \
+	 (1UL << (63 - 49))  /* Emergency Signal */		| \
+	 (1UL << (63 - 50))  /* External Call */		| \
+	 (1UL << (63 - 52))  /* Clock Comparator */		| \
+	 (1UL << (63 - 53))  /* CPU Timer */			| \
+	 (1UL << (63 - 54))  /* Service Signal */		| \
+	 (1UL << (63 - 57))  /* Interrupt Key */		| \
+	 (1UL << (63 - 58))  /* Measurement Alert */		| \
+	 (1UL << (63 - 59))  /* Timing Alert */			| \
+	 (1UL << (63 - 62))) /* IUCV */
+
 void irq_subclass_register(enum irq_subclass subclass);
 void irq_subclass_unregister(enum irq_subclass subclass);
 
diff --git a/arch/s390/include/asm/processor.h b/arch/s390/include/asm/processor.h
index 5900877bb19c..9e1cdcf8d124 100644
--- a/arch/s390/include/asm/processor.h
+++ b/arch/s390/include/asm/processor.h
@@ -15,11 +15,13 @@
 #define CIF_ASCE		1	/* user asce needs fixup / uaccess */
 #define CIF_NOHZ_DELAY		2	/* delay HZ disable for a tick */
 #define CIF_FPU			3	/* restore vector registers */
+#define CIF_IGNORE_IRQ		4	/* ignore interrupt (for udelay) */
 
 #define _CIF_MCCK_PENDING	(1<<CIF_MCCK_PENDING)
 #define _CIF_ASCE		(1<<CIF_ASCE)
 #define _CIF_NOHZ_DELAY		(1<<CIF_NOHZ_DELAY)
 #define _CIF_FPU		(1<<CIF_FPU)
+#define _CIF_IGNORE_IRQ		(1<<CIF_IGNORE_IRQ)
 
 #ifndef __ASSEMBLY__
 
diff --git a/arch/s390/kernel/entry.S b/arch/s390/kernel/entry.S
index d653a87d66b5..857b6526d298 100644
--- a/arch/s390/kernel/entry.S
+++ b/arch/s390/kernel/entry.S
@@ -563,6 +563,8 @@ ENTRY(io_int_handler)
 	stmg	%r8,%r9,__PT_PSW(%r11)
 	mvc	__PT_INT_CODE(12,%r11),__LC_SUBCHANNEL_ID
 	xc	__PT_FLAGS(8,%r11),__PT_FLAGS(%r11)
+	TSTMSK	__LC_CPU_FLAGS,_CIF_IGNORE_IRQ
+	jo	.Lio_restore
 	TRACE_IRQS_OFF
 	xc	__SF_BACKCHAIN(8,%r15),__SF_BACKCHAIN(%r15)
 .Lio_loop:
@@ -738,6 +740,8 @@ ENTRY(ext_int_handler)
 	mvc	__PT_INT_PARM(4,%r11),__LC_EXT_PARAMS
 	mvc	__PT_INT_PARM_LONG(8,%r11),0(%r1)
 	xc	__PT_FLAGS(8,%r11),__PT_FLAGS(%r11)
+	TSTMSK	__LC_CPU_FLAGS,_CIF_IGNORE_IRQ
+	jo	.Lio_restore
 	TRACE_IRQS_OFF
 	xc	__SF_BACKCHAIN(8,%r15),__SF_BACKCHAIN(%r15)
 	lgr	%r2,%r11		# pass pointer to pt_regs
diff --git a/arch/s390/kernel/entry.h b/arch/s390/kernel/entry.h
index 3eecd0f7adb2..b7019ab74070 100644
--- a/arch/s390/kernel/entry.h
+++ b/arch/s390/kernel/entry.h
@@ -16,7 +16,6 @@ void io_int_handler(void);
 void mcck_int_handler(void);
 void restart_int_handler(void);
 void restart_call_handler(void);
-void psw_idle(struct s390_idle_data *, unsigned long);
 
 asmlinkage long do_syscall_trace_enter(struct pt_regs *regs);
 asmlinkage void do_syscall_trace_exit(struct pt_regs *regs);
diff --git a/arch/s390/lib/delay.c b/arch/s390/lib/delay.c
index 246a7eb4b680..501dcd4ca4a0 100644
--- a/arch/s390/lib/delay.c
+++ b/arch/s390/lib/delay.c
@@ -12,8 +12,10 @@
 #include <linux/module.h>
 #include <linux/irqflags.h>
 #include <linux/interrupt.h>
+#include <linux/irq.h>
 #include <asm/vtimer.h>
 #include <asm/div64.h>
+#include <asm/idle.h>
 
 void __delay(unsigned long loops)
 {
@@ -30,26 +32,22 @@ EXPORT_SYMBOL(__delay);
 
 static void __udelay_disabled(unsigned long long usecs)
 {
-	unsigned long cr0, cr6, new;
-	u64 clock_saved, end;
+	unsigned long cr0, cr0_new, psw_mask;
+	struct s390_idle_data idle;
+	u64 end;
 
 	end = get_tod_clock() + (usecs << 12);
-	clock_saved = local_tick_disable();
 	__ctl_store(cr0, 0, 0);
-	__ctl_store(cr6, 6, 6);
-	new = (cr0 &  0xffff00e0) | 0x00000800;
-	__ctl_load(new , 0, 0);
-	new = 0;
-	__ctl_load(new, 6, 6);
-	lockdep_off();
-	do {
-		set_clock_comparator(end);
-		enabled_wait();
-	} while (get_tod_clock_fast() < end);
-	lockdep_on();
+	cr0_new = cr0 & ~CR0_IRQ_SUBCLASS_MASK;
+	cr0_new |= (1UL << (63 - 52)); /* enable clock comparator irq */
+	__ctl_load(cr0_new, 0, 0);
+	psw_mask = __extract_psw() | PSW_MASK_EXT | PSW_MASK_WAIT;
+	set_clock_comparator(end);
+	set_cpu_flag(CIF_IGNORE_IRQ);
+	psw_idle(&idle, psw_mask);
+	clear_cpu_flag(CIF_IGNORE_IRQ);
+	set_clock_comparator(S390_lowcore.clock_comparator);
 	__ctl_load(cr0, 0, 0);
-	__ctl_load(cr6, 6, 6);
-	local_tick_enable(clock_saved);
 }
 
 static void __udelay_enabled(unsigned long long usecs)