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b2441318 | 1 | // SPDX-License-Identifier: GPL-2.0 |
b5f87f15 MS |
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/kprobes.h> | |
13 | #include <linux/notifier.h> | |
14 | #include <linux/init.h> | |
15 | #include <linux/cpu.h> | |
32ef5517 | 16 | #include <linux/sched/cputime.h> |
b5f87f15 MS |
17 | #include <asm/nmi.h> |
18 | #include <asm/smp.h> | |
19 | #include "entry.h" | |
20 | ||
21 | static DEFINE_PER_CPU(struct s390_idle_data, s390_idle); | |
22 | ||
7a5388de | 23 | void enabled_wait(void) |
b5f87f15 | 24 | { |
0429fbc0 | 25 | struct s390_idle_data *idle = this_cpu_ptr(&s390_idle); |
b5f87f15 MS |
26 | unsigned long long idle_time; |
27 | unsigned long psw_mask; | |
28 | ||
29 | trace_hardirqs_on(); | |
30 | ||
31 | /* Wait for external, I/O or machine check interrupt. */ | |
32 | psw_mask = PSW_KERNEL_BITS | PSW_MASK_WAIT | PSW_MASK_DAT | | |
33 | PSW_MASK_IO | PSW_MASK_EXT | PSW_MASK_MCHECK; | |
34 | clear_cpu_flag(CIF_NOHZ_DELAY); | |
35 | ||
36 | /* Call the assembler magic in entry.S */ | |
37 | psw_idle(idle, psw_mask); | |
38 | ||
200e7c0f HC |
39 | trace_hardirqs_off(); |
40 | ||
b5f87f15 | 41 | /* Account time spent with enabled wait psw loaded as idle time. */ |
1ce21804 | 42 | write_seqcount_begin(&idle->seqcount); |
b5f87f15 MS |
43 | idle_time = idle->clock_idle_exit - idle->clock_idle_enter; |
44 | idle->clock_idle_enter = idle->clock_idle_exit = 0ULL; | |
45 | idle->idle_time += idle_time; | |
46 | idle->idle_count++; | |
18b43a9b | 47 | account_idle_time(cputime_to_nsecs(idle_time)); |
1ce21804 | 48 | write_seqcount_end(&idle->seqcount); |
b5f87f15 | 49 | } |
7a5388de | 50 | NOKPROBE_SYMBOL(enabled_wait); |
b5f87f15 MS |
51 | |
52 | static ssize_t show_idle_count(struct device *dev, | |
53 | struct device_attribute *attr, char *buf) | |
54 | { | |
55 | struct s390_idle_data *idle = &per_cpu(s390_idle, dev->id); | |
56 | unsigned long long idle_count; | |
1ce21804 | 57 | unsigned int seq; |
b5f87f15 MS |
58 | |
59 | do { | |
1ce21804 | 60 | seq = read_seqcount_begin(&idle->seqcount); |
187b5f41 CB |
61 | idle_count = READ_ONCE(idle->idle_count); |
62 | if (READ_ONCE(idle->clock_idle_enter)) | |
b5f87f15 | 63 | idle_count++; |
1ce21804 | 64 | } while (read_seqcount_retry(&idle->seqcount, seq)); |
b5f87f15 MS |
65 | return sprintf(buf, "%llu\n", idle_count); |
66 | } | |
67 | DEVICE_ATTR(idle_count, 0444, show_idle_count, NULL); | |
68 | ||
69 | static ssize_t show_idle_time(struct device *dev, | |
70 | struct device_attribute *attr, char *buf) | |
71 | { | |
72 | struct s390_idle_data *idle = &per_cpu(s390_idle, dev->id); | |
73 | unsigned long long now, idle_time, idle_enter, idle_exit; | |
1ce21804 | 74 | unsigned int seq; |
b5f87f15 MS |
75 | |
76 | do { | |
77 | now = get_tod_clock(); | |
1ce21804 | 78 | seq = read_seqcount_begin(&idle->seqcount); |
187b5f41 CB |
79 | idle_time = READ_ONCE(idle->idle_time); |
80 | idle_enter = READ_ONCE(idle->clock_idle_enter); | |
81 | idle_exit = READ_ONCE(idle->clock_idle_exit); | |
1ce21804 | 82 | } while (read_seqcount_retry(&idle->seqcount, seq)); |
b5f87f15 MS |
83 | idle_time += idle_enter ? ((idle_exit ? : now) - idle_enter) : 0; |
84 | return sprintf(buf, "%llu\n", idle_time >> 12); | |
85 | } | |
86 | DEVICE_ATTR(idle_time_us, 0444, show_idle_time, NULL); | |
87 | ||
42b425b3 | 88 | u64 arch_cpu_idle_time(int cpu) |
b5f87f15 MS |
89 | { |
90 | struct s390_idle_data *idle = &per_cpu(s390_idle, cpu); | |
91 | unsigned long long now, idle_enter, idle_exit; | |
1ce21804 | 92 | unsigned int seq; |
b5f87f15 MS |
93 | |
94 | do { | |
95 | now = get_tod_clock(); | |
1ce21804 | 96 | seq = read_seqcount_begin(&idle->seqcount); |
187b5f41 CB |
97 | idle_enter = READ_ONCE(idle->clock_idle_enter); |
98 | idle_exit = READ_ONCE(idle->clock_idle_exit); | |
1ce21804 | 99 | } while (read_seqcount_retry(&idle->seqcount, seq)); |
42b425b3 FW |
100 | |
101 | return cputime_to_nsecs(idle_enter ? ((idle_exit ?: now) - idle_enter) : 0); | |
b5f87f15 MS |
102 | } |
103 | ||
104 | void arch_cpu_idle_enter(void) | |
105 | { | |
106 | local_mcck_disable(); | |
107 | } | |
108 | ||
109 | void arch_cpu_idle(void) | |
110 | { | |
111 | if (!test_cpu_flag(CIF_MCCK_PENDING)) | |
112 | /* Halt the cpu and keep track of cpu time accounting. */ | |
113 | enabled_wait(); | |
114 | local_irq_enable(); | |
115 | } | |
116 | ||
117 | void arch_cpu_idle_exit(void) | |
118 | { | |
119 | local_mcck_enable(); | |
120 | if (test_cpu_flag(CIF_MCCK_PENDING)) | |
121 | s390_handle_mcck(); | |
122 | } | |
123 | ||
124 | void arch_cpu_idle_dead(void) | |
125 | { | |
126 | cpu_die(); | |
127 | } |