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 | 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 | |
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 | |
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 | |
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, fmt: "%lu\n" , READ_ONCE(idle->idle_time) >> 12); |
80 | } |
81 | DEVICE_ATTR(idle_time_us, 0444, show_idle_time, NULL); |
82 | |
83 | void arch_cpu_idle_enter(void) |
84 | { |
85 | } |
86 | |
87 | void arch_cpu_idle_exit(void) |
88 | { |
89 | } |
90 | |
91 | void __noreturn arch_cpu_idle_dead(void) |
92 | { |
93 | cpu_die(); |
94 | } |
95 | |