1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * Idle functions for s390.
4 *
5 * Copyright IBM Corp. 2014
6 *
7 * Author(s): Martin Schwidefsky <schwidefsky@de.ibm.com>
8 */
9
10 #include <linux/kernel.h>
11 #include <linux/kernel_stat.h>
12 #include <linux/notifier.h>
13 #include <linux/init.h>
14 #include <linux/cpu.h>
15 #include <trace/events/power.h>
16 #include <asm/cpu_mf.h>
17 #include <asm/cputime.h>
18 #include <asm/nmi.h>
19 #include <asm/smp.h>
20 #include "entry.h"
21
22 static DEFINE_PER_CPU(struct s390_idle_data, s390_idle);
23
account_idle_time_irq(void)24 void account_idle_time_irq(void)
25 {
26 struct s390_idle_data *idle = this_cpu_ptr(&s390_idle);
27 unsigned long idle_time;
28 u64 cycles_new[8];
29 int i;
30
31 if (smp_cpu_mtid) {
32 stcctm(MT_DIAG, smp_cpu_mtid, cycles_new);
33 for (i = 0; i < smp_cpu_mtid; i++)
34 this_cpu_add(mt_cycles[i], cycles_new[i] - idle->mt_cycles_enter[i]);
35 }
36
37 idle_time = S390_lowcore.int_clock - idle->clock_idle_enter;
38
39 S390_lowcore.steal_timer += idle->clock_idle_enter - S390_lowcore.last_update_clock;
40 S390_lowcore.last_update_clock = S390_lowcore.int_clock;
41
42 S390_lowcore.system_timer += S390_lowcore.last_update_timer - idle->timer_idle_enter;
43 S390_lowcore.last_update_timer = S390_lowcore.sys_enter_timer;
44
45 /* Account time spent with enabled wait psw loaded as idle time. */
46 WRITE_ONCE(idle->idle_time, READ_ONCE(idle->idle_time) + idle_time);
47 WRITE_ONCE(idle->idle_count, READ_ONCE(idle->idle_count) + 1);
48 account_idle_time(cputime_to_nsecs(idle_time));
49 }
50
arch_cpu_idle(void)51 void noinstr arch_cpu_idle(void)
52 {
53 struct s390_idle_data *idle = this_cpu_ptr(&s390_idle);
54 unsigned long psw_mask;
55
56 /* Wait for external, I/O or machine check interrupt. */
57 psw_mask = PSW_KERNEL_BITS | PSW_MASK_WAIT |
58 PSW_MASK_IO | PSW_MASK_EXT | PSW_MASK_MCHECK;
59 clear_cpu_flag(CIF_NOHZ_DELAY);
60
61 /* psw_idle() returns with interrupts disabled. */
62 psw_idle(idle, psw_mask);
63 }
64
show_idle_count(struct device * dev,struct device_attribute * attr,char * buf)65 static ssize_t show_idle_count(struct device *dev,
66 struct device_attribute *attr, char *buf)
67 {
68 struct s390_idle_data *idle = &per_cpu(s390_idle, dev->id);
69
70 return sysfs_emit(buf, "%lu\n", READ_ONCE(idle->idle_count));
71 }
72 DEVICE_ATTR(idle_count, 0444, show_idle_count, NULL);
73
show_idle_time(struct device * dev,struct device_attribute * attr,char * buf)74 static ssize_t show_idle_time(struct device *dev,
75 struct device_attribute *attr, char *buf)
76 {
77 struct s390_idle_data *idle = &per_cpu(s390_idle, dev->id);
78
79 return sysfs_emit(buf, "%lu\n", READ_ONCE(idle->idle_time) >> 12);
80 }
81 DEVICE_ATTR(idle_time_us, 0444, show_idle_time, NULL);
82
arch_cpu_idle_enter(void)83 void arch_cpu_idle_enter(void)
84 {
85 }
86
arch_cpu_idle_exit(void)87 void arch_cpu_idle_exit(void)
88 {
89 }
90
arch_cpu_idle_dead(void)91 void __noreturn arch_cpu_idle_dead(void)
92 {
93 cpu_die();
94 }
95