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 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 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 47 void arch_cpu_idle(void) 48 { 49 struct s390_idle_data *idle = this_cpu_ptr(&s390_idle); 50 unsigned long 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 72 static 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 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, "%llu\n", idle_count); 86 } 87 DEVICE_ATTR(idle_count, 0444, show_idle_count, NULL); 88 89 static ssize_t show_idle_time(struct device *dev, 90 struct device_attribute *attr, char *buf) 91 { 92 unsigned long 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, "%llu\n", idle_time >> 12); 113 } 114 DEVICE_ATTR(idle_time_us, 0444, show_idle_time, NULL); 115 116 u64 arch_cpu_idle_time(int cpu) 117 { 118 struct s390_idle_data *idle = &per_cpu(s390_idle, cpu); 119 unsigned long 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 } 138 139 void arch_cpu_idle_enter(void) 140 { 141 } 142 143 void arch_cpu_idle_exit(void) 144 { 145 } 146 147 void arch_cpu_idle_dead(void) 148 { 149 cpu_die(); 150 } 151