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 account_idle_time(cputime_to_nsecs(idle_time)); 35 } 36 37 void noinstr arch_cpu_idle(void) 38 { 39 struct s390_idle_data *idle = this_cpu_ptr(&s390_idle); 40 unsigned long psw_mask; 41 42 /* Wait for external, I/O or machine check interrupt. */ 43 psw_mask = PSW_KERNEL_BITS | PSW_MASK_WAIT | 44 PSW_MASK_IO | PSW_MASK_EXT | PSW_MASK_MCHECK; 45 clear_cpu_flag(CIF_NOHZ_DELAY); 46 set_cpu_flag(CIF_ENABLED_WAIT); 47 if (smp_cpu_mtid) 48 stcctm(MT_DIAG, smp_cpu_mtid, (u64 *)&idle->mt_cycles_enter); 49 idle->clock_idle_enter = get_tod_clock_fast(); 50 idle->timer_idle_enter = get_cpu_timer(); 51 bpon(); 52 __load_psw_mask(psw_mask); 53 } 54 55 static ssize_t show_idle_count(struct device *dev, 56 struct device_attribute *attr, char *buf) 57 { 58 struct s390_idle_data *idle = &per_cpu(s390_idle, dev->id); 59 60 return sysfs_emit(buf, "%lu\n", READ_ONCE(idle->idle_count)); 61 } 62 DEVICE_ATTR(idle_count, 0444, show_idle_count, NULL); 63 64 static ssize_t show_idle_time(struct device *dev, 65 struct device_attribute *attr, char *buf) 66 { 67 struct s390_idle_data *idle = &per_cpu(s390_idle, dev->id); 68 69 return sysfs_emit(buf, "%lu\n", READ_ONCE(idle->idle_time) >> 12); 70 } 71 DEVICE_ATTR(idle_time_us, 0444, show_idle_time, NULL); 72 73 void arch_cpu_idle_enter(void) 74 { 75 } 76 77 void arch_cpu_idle_exit(void) 78 { 79 } 80 81 void __noreturn arch_cpu_idle_dead(void) 82 { 83 cpu_die(); 84 } 85