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/idle.h> 19 #include <asm/nmi.h> 20 #include <asm/smp.h> 21 22 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 29 idle_time = get_lowcore()->int_clock - idle->clock_idle_enter; 30 31 /* Account time spent with enabled wait psw loaded as idle time. */ 32 __atomic64_add(idle_time, &idle->idle_time); 33 __atomic64_add_const(1, &idle->idle_count); 34 35 /* Dyntick idle time accounted by nohz/scheduler */ 36 if (!idle->idle_dyntick) 37 account_idle_time(cputime_to_nsecs(idle_time)); 38 } 39 40 void noinstr arch_cpu_idle(void) 41 { 42 struct s390_idle_data *idle = this_cpu_ptr(&s390_idle); 43 unsigned long psw_mask; 44 45 /* Wait for external, I/O or machine check interrupt. */ 46 psw_mask = PSW_KERNEL_BITS | PSW_MASK_WAIT | 47 PSW_MASK_IO | PSW_MASK_EXT | PSW_MASK_MCHECK; 48 clear_cpu_flag(CIF_NOHZ_DELAY); 49 set_cpu_flag(CIF_ENABLED_WAIT); 50 if (smp_cpu_mtid) 51 stcctm(MT_DIAG, smp_cpu_mtid, (u64 *)&idle->mt_cycles_enter); 52 idle->clock_idle_enter = get_tod_clock_fast(); 53 idle->timer_idle_enter = get_cpu_timer(); 54 bpon(); 55 __load_psw_mask(psw_mask); 56 } 57 58 static ssize_t show_idle_count(struct device *dev, 59 struct device_attribute *attr, char *buf) 60 { 61 struct s390_idle_data *idle = &per_cpu(s390_idle, dev->id); 62 63 return sysfs_emit(buf, "%lu\n", READ_ONCE(idle->idle_count)); 64 } 65 DEVICE_ATTR(idle_count, 0444, show_idle_count, NULL); 66 67 static ssize_t show_idle_time(struct device *dev, 68 struct device_attribute *attr, char *buf) 69 { 70 struct s390_idle_data *idle = &per_cpu(s390_idle, dev->id); 71 72 return sysfs_emit(buf, "%lu\n", READ_ONCE(idle->idle_time) >> 12); 73 } 74 DEVICE_ATTR(idle_time_us, 0444, show_idle_time, NULL); 75 76 void arch_cpu_idle_enter(void) 77 { 78 } 79 80 void arch_cpu_idle_exit(void) 81 { 82 } 83 84 void __noreturn arch_cpu_idle_dead(void) 85 { 86 cpu_die(); 87 } 88