1 files changed, 20 insertions, 76 deletions

diff --git a/arch/s390/kernel/idle.c b/arch/s390/kernel/idle.c
index 4bf1ee293f2b..e7239aaf428b 100644
--- a/arch/s390/kernel/idle.c
+++ b/arch/s390/kernel/idle.c
@@ -12,9 +12,9 @@
 #include <linux/notifier.h>
 #include <linux/init.h>
 #include <linux/cpu.h>
-#include <linux/sched/cputime.h>
 #include <trace/events/power.h>
 #include <asm/cpu_mf.h>
+#include <asm/cputime.h>
 #include <asm/nmi.h>
 #include <asm/smp.h>
 #include "entry.h"
@@ -24,117 +24,61 @@ static DEFINE_PER_CPU(struct s390_idle_data, s390_idle);
 void account_idle_time_irq(void)
 {
 	struct s390_idle_data *idle = this_cpu_ptr(&s390_idle);
+	unsigned long idle_time;
 	u64 cycles_new[8];
 	int i;
 
-	clear_cpu_flag(CIF_ENABLED_WAIT);
 	if (smp_cpu_mtid) {
 		stcctm(MT_DIAG, smp_cpu_mtid, cycles_new);
 		for (i = 0; i < smp_cpu_mtid; i++)
 			this_cpu_add(mt_cycles[i], cycles_new[i] - idle->mt_cycles_enter[i]);
 	}
 
-	idle->clock_idle_exit = S390_lowcore.int_clock;
-	idle->timer_idle_exit = S390_lowcore.sys_enter_timer;
+	idle_time = S390_lowcore.int_clock - idle->clock_idle_enter;
 
 	S390_lowcore.steal_timer += idle->clock_idle_enter - S390_lowcore.last_update_clock;
-	S390_lowcore.last_update_clock = idle->clock_idle_exit;
+	S390_lowcore.last_update_clock = S390_lowcore.int_clock;
 
 	S390_lowcore.system_timer += S390_lowcore.last_update_timer - idle->timer_idle_enter;
-	S390_lowcore.last_update_timer = idle->timer_idle_exit;
+	S390_lowcore.last_update_timer = S390_lowcore.sys_enter_timer;
+
+	/* Account time spent with enabled wait psw loaded as idle time. */
+	WRITE_ONCE(idle->idle_time, READ_ONCE(idle->idle_time) + idle_time);
+	WRITE_ONCE(idle->idle_count, READ_ONCE(idle->idle_count) + 1);
+	account_idle_time(cputime_to_nsecs(idle_time));
 }
 
-void arch_cpu_idle(void)
+void noinstr arch_cpu_idle(void)
 {
 	struct s390_idle_data *idle = this_cpu_ptr(&s390_idle);
-	unsigned long idle_time;
 	unsigned long psw_mask;
 
 	/* Wait for external, I/O or machine check interrupt. */
-	psw_mask = PSW_KERNEL_BITS | PSW_MASK_WAIT | PSW_MASK_DAT |
-		PSW_MASK_IO | PSW_MASK_EXT | PSW_MASK_MCHECK;
+	psw_mask = PSW_KERNEL_BITS | PSW_MASK_WAIT |
+		   PSW_MASK_IO | PSW_MASK_EXT | PSW_MASK_MCHECK;
 	clear_cpu_flag(CIF_NOHZ_DELAY);
 
 	/* psw_idle() returns with interrupts disabled. */
 	psw_idle(idle, psw_mask);
-
-	/* Account time spent with enabled wait psw loaded as idle time. */
-	raw_write_seqcount_begin(&idle->seqcount);
-	idle_time = idle->clock_idle_exit - idle->clock_idle_enter;
-	idle->clock_idle_enter = idle->clock_idle_exit = 0ULL;
-	idle->idle_time += idle_time;
-	idle->idle_count++;
-	account_idle_time(cputime_to_nsecs(idle_time));
-	raw_write_seqcount_end(&idle->seqcount);
-	raw_local_irq_enable();
 }
 
 static ssize_t show_idle_count(struct device *dev,
-				struct device_attribute *attr, char *buf)
+			       struct device_attribute *attr, char *buf)
 {
 	struct s390_idle_data *idle = &per_cpu(s390_idle, dev->id);
-	unsigned long idle_count;
-	unsigned int seq;
-
-	do {
-		seq = read_seqcount_begin(&idle->seqcount);
-		idle_count = READ_ONCE(idle->idle_count);
-		if (READ_ONCE(idle->clock_idle_enter))
-			idle_count++;
-	} while (read_seqcount_retry(&idle->seqcount, seq));
-	return sprintf(buf, "%lu\n", idle_count);
+
+	return sysfs_emit(buf, "%lu\n", READ_ONCE(idle->idle_count));
 }
 DEVICE_ATTR(idle_count, 0444, show_idle_count, NULL);
 
 static ssize_t show_idle_time(struct device *dev,
-				struct device_attribute *attr, char *buf)
+			      struct device_attribute *attr, char *buf)
 {
-	unsigned long now, idle_time, idle_enter, idle_exit, in_idle;
 	struct s390_idle_data *idle = &per_cpu(s390_idle, dev->id);
-	unsigned int seq;
-
-	do {
-		seq = read_seqcount_begin(&idle->seqcount);
-		idle_time = READ_ONCE(idle->idle_time);
-		idle_enter = READ_ONCE(idle->clock_idle_enter);
-		idle_exit = READ_ONCE(idle->clock_idle_exit);
-	} while (read_seqcount_retry(&idle->seqcount, seq));
-	in_idle = 0;
-	now = get_tod_clock();
-	if (idle_enter) {
-		if (idle_exit) {
-			in_idle = idle_exit - idle_enter;
-		} else if (now > idle_enter) {
-			in_idle = now - idle_enter;
-		}
-	}
-	idle_time += in_idle;
-	return sprintf(buf, "%lu\n", idle_time >> 12);
-}
-DEVICE_ATTR(idle_time_us, 0444, show_idle_time, NULL);
 
-u64 arch_cpu_idle_time(int cpu)
-{
-	struct s390_idle_data *idle = &per_cpu(s390_idle, cpu);
-	unsigned long now, idle_enter, idle_exit, in_idle;
-	unsigned int seq;
-
-	do {
-		seq = read_seqcount_begin(&idle->seqcount);
-		idle_enter = READ_ONCE(idle->clock_idle_enter);
-		idle_exit = READ_ONCE(idle->clock_idle_exit);
-	} while (read_seqcount_retry(&idle->seqcount, seq));
-	in_idle = 0;
-	now = get_tod_clock();
-	if (idle_enter) {
-		if (idle_exit) {
-			in_idle = idle_exit - idle_enter;
-		} else if (now > idle_enter) {
-			in_idle = now - idle_enter;
-		}
-	}
-	return cputime_to_nsecs(in_idle);
+	return sysfs_emit(buf, "%lu\n", READ_ONCE(idle->idle_time) >> 12);
 }
+DEVICE_ATTR(idle_time_us, 0444, show_idle_time, NULL);
 
 void arch_cpu_idle_enter(void)
 {
@@ -144,7 +88,7 @@ void arch_cpu_idle_exit(void)
 {
 }
 
-void arch_cpu_idle_dead(void)
+void __noreturn arch_cpu_idle_dead(void)
 {
 	cpu_die();
 }