diff --git a/arch/s390/include/asm/delay.h b/arch/s390/include/asm/delay.h
index 4a08379cd1eb..b566be6f13f3 100644
--- a/arch/s390/include/asm/delay.h
+++ b/arch/s390/include/asm/delay.h
@@ -14,13 +14,13 @@
 #define _S390_DELAY_H
 
 void udelay_enable(void);
-void __ndelay(unsigned long long nsecs);
-void __udelay(unsigned long long usecs);
-void udelay_simple(unsigned long long usecs);
+void __ndelay(unsigned long nsecs);
+void __udelay(unsigned long usecs);
+void udelay_simple(unsigned long usecs);
 void __delay(unsigned long loops);
 
-#define ndelay(n) __ndelay((unsigned long long) (n))
-#define udelay(n) __udelay((unsigned long long) (n))
-#define mdelay(n) __udelay((unsigned long long) (n) * 1000)
+#define ndelay(n) __ndelay((unsigned long)(n))
+#define udelay(n) __udelay((unsigned long)(n))
+#define mdelay(n) __udelay((unsigned long)(n) * 1000)
 
 #endif /* defined(_S390_DELAY_H) */
diff --git a/arch/s390/include/asm/processor.h b/arch/s390/include/asm/processor.h
index 6b7269f51f83..85dfbb20467e 100644
--- a/arch/s390/include/asm/processor.h
+++ b/arch/s390/include/asm/processor.h
@@ -16,14 +16,12 @@
 
 #define CIF_NOHZ_DELAY		2	/* delay HZ disable for a tick */
 #define CIF_FPU			3	/* restore FPU registers */
-#define CIF_IGNORE_IRQ		4	/* ignore interrupt (for udelay) */
 #define CIF_ENABLED_WAIT	5	/* in enabled wait state */
 #define CIF_MCCK_GUEST		6	/* machine check happening in guest */
 #define CIF_DEDICATED_CPU	7	/* this CPU is dedicated */
 
 #define _CIF_NOHZ_DELAY		BIT(CIF_NOHZ_DELAY)
 #define _CIF_FPU		BIT(CIF_FPU)
-#define _CIF_IGNORE_IRQ		BIT(CIF_IGNORE_IRQ)
 #define _CIF_ENABLED_WAIT	BIT(CIF_ENABLED_WAIT)
 #define _CIF_MCCK_GUEST		BIT(CIF_MCCK_GUEST)
 #define _CIF_DEDICATED_CPU	BIT(CIF_DEDICATED_CPU)
diff --git a/arch/s390/kernel/entry.S b/arch/s390/kernel/entry.S
index 2cc338aa3f65..87e83164c330 100644
--- a/arch/s390/kernel/entry.S
+++ b/arch/s390/kernel/entry.S
@@ -779,8 +779,6 @@ ENTRY(io_int_handler)
 	xc	__PT_FLAGS(8,%r11),__PT_FLAGS(%r11)
 	xc	__SF_BACKCHAIN(8,%r15),__SF_BACKCHAIN(%r15)
 	TRACE_IRQS_OFF
-	TSTMSK	__LC_CPU_FLAGS,_CIF_IGNORE_IRQ
-	jo	.Lio_restore
 .Lio_loop:
 	lgr	%r2,%r11		# pass pointer to pt_regs
 	lghi	%r3,IO_INTERRUPT
@@ -967,8 +965,6 @@ ENTRY(ext_int_handler)
 	xc	__PT_FLAGS(8,%r11),__PT_FLAGS(%r11)
 	xc	__SF_BACKCHAIN(8,%r15),__SF_BACKCHAIN(%r15)
 	TRACE_IRQS_OFF
-	TSTMSK	__LC_CPU_FLAGS,_CIF_IGNORE_IRQ
-	jo	.Lio_restore
 	lgr	%r2,%r11		# pass pointer to pt_regs
 	lghi	%r3,EXT_INTERRUPT
 	brasl	%r14,do_IRQ
diff --git a/arch/s390/lib/delay.c b/arch/s390/lib/delay.c
index 68d61f2835df..928b1dbe182c 100644
--- a/arch/s390/lib/delay.c
+++ b/arch/s390/lib/delay.c
@@ -39,79 +39,24 @@ void __delay(unsigned long loops)
 }
 EXPORT_SYMBOL(__delay);
 
-static void __udelay_disabled(unsigned long long usecs)
+static void delay_loop(unsigned long delta, bool simple)
 {
-	unsigned long cr0, cr0_new, psw_mask;
-	struct s390_idle_data idle;
-	u64 end;
+	unsigned long end;
 
-	end = get_tod_clock() + (usecs << 12);
-	__ctl_store(cr0, 0, 0);
-	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);
-	trace_hardirqs_off();
-	clear_cpu_flag(CIF_IGNORE_IRQ);
-	set_clock_comparator(S390_lowcore.clock_comparator);
-	__ctl_load(cr0, 0, 0);
+	if (static_branch_likely(&udelay_ready) && !simple) {
+		end = get_tod_clock_monotonic() + delta;
+		while (!tod_after(get_tod_clock_monotonic(), end))
+			cpu_relax();
+	} else {
+		end = get_tod_clock() + delta;
+		while (!tod_after(get_tod_clock(), end))
+			cpu_relax();
+	}
 }
 
-static void __udelay_enabled(unsigned long long usecs)
+void __udelay(unsigned long usecs)
 {
-	u64 clock_saved, end;
-
-	end = get_tod_clock_fast() + (usecs << 12);
-	do {
-		clock_saved = 0;
-		if (tod_after(S390_lowcore.clock_comparator, end)) {
-			clock_saved = local_tick_disable();
-			set_clock_comparator(end);
-		}
-		enabled_wait();
-		if (clock_saved)
-			local_tick_enable(clock_saved);
-	} while (get_tod_clock_fast() < end);
-}
-
-/*
- * Waits for 'usecs' microseconds using the TOD clock comparator.
- */
-void __udelay(unsigned long long usecs)
-{
-	unsigned long flags;
-
-	if (!static_branch_likely(&udelay_ready)) {
-		udelay_simple(usecs);
-		return;
-	}
-
-	preempt_disable();
-	local_irq_save(flags);
-	if (in_irq()) {
-		__udelay_disabled(usecs);
-		goto out;
-	}
-	if (in_softirq()) {
-		if (raw_irqs_disabled_flags(flags))
-			__udelay_disabled(usecs);
-		else
-			__udelay_enabled(usecs);
-		goto out;
-	}
-	if (raw_irqs_disabled_flags(flags)) {
-		local_bh_disable();
-		__udelay_disabled(usecs);
-		_local_bh_enable();
-		goto out;
-	}
-	__udelay_enabled(usecs);
-out:
-	local_irq_restore(flags);
-	preempt_enable();
+	delay_loop(usecs << 12, 0);
 }
 EXPORT_SYMBOL(__udelay);
 
@@ -119,25 +64,15 @@ EXPORT_SYMBOL(__udelay);
  * Simple udelay variant. To be used on startup and reboot
  * when the interrupt handler isn't working.
  */
-void udelay_simple(unsigned long long usecs)
+void udelay_simple(unsigned long usecs)
 {
-	u64 end;
-
-	end = get_tod_clock_fast() + (usecs << 12);
-	while (get_tod_clock_fast() < end)
-		cpu_relax();
+	delay_loop(usecs << 12, 1);
 }
 
-void __ndelay(unsigned long long nsecs)
+void __ndelay(unsigned long nsecs)
 {
-	u64 end;
-
 	nsecs <<= 9;
 	do_div(nsecs, 125);
-	end = get_tod_clock_fast() + nsecs;
-	if (nsecs & ~0xfffUL)
-		__udelay(nsecs >> 12);
-	while (get_tod_clock_fast() < end)
-		barrier();
+	delay_loop(nsecs, 0);
 }
 EXPORT_SYMBOL(__ndelay);