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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 <linux/sched/cputime.h>
16#include <trace/events/power.h>
17#include <asm/cpu_mf.h>
18#include <asm/nmi.h>
19#include <asm/smp.h>
20#include "entry.h"
21
22static DEFINE_PER_CPU(struct s390_idle_data, s390_idle);
23
24void account_idle_time_irq(void)
25{
26 struct s390_idle_data *idle = this_cpu_ptr(&s390_idle);
27 u64 cycles_new[8];
28 int i;
29
30 clear_cpu_flag(CIF_ENABLED_WAIT);
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->clock_idle_exit = S390_lowcore.int_clock;
38 idle->timer_idle_exit = S390_lowcore.sys_enter_timer;
39
40 S390_lowcore.steal_timer += idle->clock_idle_enter - S390_lowcore.last_update_clock;
41 S390_lowcore.last_update_clock = idle->clock_idle_exit;
42
43 S390_lowcore.system_timer += S390_lowcore.last_update_timer - idle->timer_idle_enter;
44 S390_lowcore.last_update_timer = idle->timer_idle_exit;
45}
46
47void arch_cpu_idle(void)
48{
49 struct s390_idle_data *idle = this_cpu_ptr(&s390_idle);
50 unsigned long idle_time;
51 unsigned long psw_mask;
52
53 /* Wait for external, I/O or machine check interrupt. */
54 psw_mask = PSW_KERNEL_BITS | PSW_MASK_WAIT | PSW_MASK_DAT |
55 PSW_MASK_IO | PSW_MASK_EXT | PSW_MASK_MCHECK;
56 clear_cpu_flag(CIF_NOHZ_DELAY);
57
58 /* psw_idle() returns with interrupts disabled. */
59 psw_idle(idle, psw_mask);
60
61 /* Account time spent with enabled wait psw loaded as idle time. */
62 raw_write_seqcount_begin(&idle->seqcount);
63 idle_time = idle->clock_idle_exit - idle->clock_idle_enter;
64 idle->clock_idle_enter = idle->clock_idle_exit = 0ULL;
65 idle->idle_time += idle_time;
66 idle->idle_count++;
67 account_idle_time(cputime_to_nsecs(idle_time));
68 raw_write_seqcount_end(&idle->seqcount);
69 raw_local_irq_enable();
70}
71
72static ssize_t show_idle_count(struct device *dev,
73 struct device_attribute *attr, char *buf)
74{
75 struct s390_idle_data *idle = &per_cpu(s390_idle, dev->id);
76 unsigned long idle_count;
77 unsigned int seq;
78
79 do {
80 seq = read_seqcount_begin(&idle->seqcount);
81 idle_count = READ_ONCE(idle->idle_count);
82 if (READ_ONCE(idle->clock_idle_enter))
83 idle_count++;
84 } while (read_seqcount_retry(&idle->seqcount, seq));
85 return sprintf(buf, "%lu\n", idle_count);
86}
87DEVICE_ATTR(idle_count, 0444, show_idle_count, NULL);
88
89static ssize_t show_idle_time(struct device *dev,
90 struct device_attribute *attr, char *buf)
91{
92 unsigned long now, idle_time, idle_enter, idle_exit, in_idle;
93 struct s390_idle_data *idle = &per_cpu(s390_idle, dev->id);
94 unsigned int seq;
95
96 do {
97 seq = read_seqcount_begin(&idle->seqcount);
98 idle_time = READ_ONCE(idle->idle_time);
99 idle_enter = READ_ONCE(idle->clock_idle_enter);
100 idle_exit = READ_ONCE(idle->clock_idle_exit);
101 } while (read_seqcount_retry(&idle->seqcount, seq));
102 in_idle = 0;
103 now = get_tod_clock();
104 if (idle_enter) {
105 if (idle_exit) {
106 in_idle = idle_exit - idle_enter;
107 } else if (now > idle_enter) {
108 in_idle = now - idle_enter;
109 }
110 }
111 idle_time += in_idle;
112 return sprintf(buf, "%lu\n", idle_time >> 12);
113}
114DEVICE_ATTR(idle_time_us, 0444, show_idle_time, NULL);
115
116u64 arch_cpu_idle_time(int cpu)
117{
118 struct s390_idle_data *idle = &per_cpu(s390_idle, cpu);
119 unsigned long now, idle_enter, idle_exit, in_idle;
120 unsigned int seq;
121
122 do {
123 seq = read_seqcount_begin(&idle->seqcount);
124 idle_enter = READ_ONCE(idle->clock_idle_enter);
125 idle_exit = READ_ONCE(idle->clock_idle_exit);
126 } while (read_seqcount_retry(&idle->seqcount, seq));
127 in_idle = 0;
128 now = get_tod_clock();
129 if (idle_enter) {
130 if (idle_exit) {
131 in_idle = idle_exit - idle_enter;
132 } else if (now > idle_enter) {
133 in_idle = now - idle_enter;
134 }
135 }
136 return cputime_to_nsecs(in_idle);
137}
138
139void arch_cpu_idle_enter(void)
140{
141}
142
143void arch_cpu_idle_exit(void)
144{
145}
146
147void arch_cpu_idle_dead(void)
148{
149 cpu_die();
150}
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
22static DEFINE_PER_CPU(struct s390_idle_data, s390_idle);
23
24void 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
51void 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
65static 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}
72DEVICE_ATTR(idle_count, 0444, show_idle_count, NULL);
73
74static 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}
81DEVICE_ATTR(idle_time_us, 0444, show_idle_time, NULL);
82
83void arch_cpu_idle_enter(void)
84{
85}
86
87void arch_cpu_idle_exit(void)
88{
89}
90
91void __noreturn arch_cpu_idle_dead(void)
92{
93 cpu_die();
94}