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