1 files changed, 94 insertions, 0 deletions
diff --git a/arch/s390/kernel/idle.c b/arch/s390/kernel/idle.c
new file mode 100644
index 0000000000..e7239aaf42
--- /dev/null
+++ b/arch/s390/kernel/idle.c
@@ -0,0 +1,94 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Idle functions for s390.
+ *
+ * Copyright IBM Corp. 2014
+ *
+ * Author(s): Martin Schwidefsky <schwidefsky@de.ibm.com>
+ */
+
+#include <linux/kernel.h>
+#include <linux/kernel_stat.h>
+#include <linux/notifier.h>
+#include <linux/init.h>
+#include <linux/cpu.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"
+
+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;
+
+	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_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 = S390_lowcore.int_clock;
+
+	S390_lowcore.system_timer += S390_lowcore.last_update_timer - idle->timer_idle_enter;
+	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 noinstr arch_cpu_idle(void)
+{
+	struct s390_idle_data *idle = this_cpu_ptr(&s390_idle);
+	unsigned long psw_mask;
+
+	/* Wait for external, I/O or machine check interrupt. */
+	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);
+}
+
+static ssize_t show_idle_count(struct device *dev,
+			       struct device_attribute *attr, char *buf)
+{
+	struct s390_idle_data *idle = &per_cpu(s390_idle, dev->id);
+
+	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 s390_idle_data *idle = &per_cpu(s390_idle, dev->id);
+
+	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)
+{
+}
+
+void arch_cpu_idle_exit(void)
+{
+}
+
+void __noreturn arch_cpu_idle_dead(void)
+{
+	cpu_die();
+}