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
24 void account_idle_time_irq(void)
25 {
26 struct s390_idle_data *idle = this_cpu_ptr(&s390_idle);
27 struct lowcore *lc = get_lowcore();
28 unsigned long idle_time;
29 u64 cycles_new[8];
30 int i;
31
32 if (smp_cpu_mtid) {
33 stcctm(MT_DIAG, smp_cpu_mtid, cycles_new);
34 for (i = 0; i < smp_cpu_mtid; i++)
35 this_cpu_add(mt_cycles[i], cycles_new[i] - idle->mt_cycles_enter[i]);
36 }
37
38 idle_time = lc->int_clock - idle->clock_idle_enter;
39
40 lc->steal_timer += idle->clock_idle_enter - lc->last_update_clock;
41 lc->last_update_clock = lc->int_clock;
42
43 lc->system_timer += lc->last_update_timer - idle->timer_idle_enter;
44 lc->last_update_timer = lc->sys_enter_timer;
45
46 /* Account time spent with enabled wait psw loaded as idle time. */
47 WRITE_ONCE(idle->idle_time, READ_ONCE(idle->idle_time) + idle_time);
48 WRITE_ONCE(idle->idle_count, READ_ONCE(idle->idle_count) + 1);
49 account_idle_time(cputime_to_nsecs(idle_time));
50 }
51
52 void noinstr arch_cpu_idle(void)
53 {
54 struct s390_idle_data *idle = this_cpu_ptr(&s390_idle);
55 unsigned long psw_mask;
56
57 /* Wait for external, I/O or machine check interrupt. */
58 psw_mask = PSW_KERNEL_BITS | PSW_MASK_WAIT |
59 PSW_MASK_IO | PSW_MASK_EXT | PSW_MASK_MCHECK;
60 clear_cpu_flag(CIF_NOHZ_DELAY);
61 set_cpu_flag(CIF_ENABLED_WAIT);
62 if (smp_cpu_mtid)
63 stcctm(MT_DIAG, smp_cpu_mtid, (u64 *)&idle->mt_cycles_enter);
64 idle->clock_idle_enter = get_tod_clock_fast();
65 idle->timer_idle_enter = get_cpu_timer();
66 bpon();
67 __load_psw_mask(psw_mask);
68 }
69
70 static ssize_t show_idle_count(struct device *dev,
71 struct device_attribute *attr, char *buf)
72 {
73 struct s390_idle_data *idle = &per_cpu(s390_idle, dev->id);
74
75 return sysfs_emit(buf, "%lu\n", READ_ONCE(idle->idle_count));
76 }
77 DEVICE_ATTR(idle_count, 0444, show_idle_count, NULL);
78
79 static ssize_t show_idle_time(struct device *dev,
80 struct device_attribute *attr, char *buf)
81 {
82 struct s390_idle_data *idle = &per_cpu(s390_idle, dev->id);
83
84 return sysfs_emit(buf, "%lu\n", READ_ONCE(idle->idle_time) >> 12);
85 }
86 DEVICE_ATTR(idle_time_us, 0444, show_idle_time, NULL);
87
88 void arch_cpu_idle_enter(void)
89 {
90 }
91
92 void arch_cpu_idle_exit(void)
93 {
94 }
95
96 void __noreturn arch_cpu_idle_dead(void)
97 {
98 cpu_die();
99 }
100
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