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 unsigned long idle_time; 28 u64 cycles_new[8]; 29 int i; 30 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_time = S390_lowcore.int_clock - idle->clock_idle_enter; 38 39 S390_lowcore.steal_timer += idle->clock_idle_enter - S390_lowcore.last_update_clock; 40 S390_lowcore.last_update_clock = S390_lowcore.int_clock; 41 42 S390_lowcore.system_timer += S390_lowcore.last_update_timer - idle->timer_idle_enter; 43 S390_lowcore.last_update_timer = S390_lowcore.sys_enter_timer; 44 45 /* Account time spent with enabled wait psw loaded as idle time. */ 46 WRITE_ONCE(idle->idle_time, READ_ONCE(idle->idle_time) + idle_time); 47 WRITE_ONCE(idle->idle_count, READ_ONCE(idle->idle_count) + 1); 48 account_idle_time(cputime_to_nsecs(idle_time)); 49 } 50 51 void noinstr arch_cpu_idle(void) 52 { 53 struct s390_idle_data *idle = this_cpu_ptr(&s390_idle); 54 unsigned long psw_mask; 55 56 /* Wait for external, I/O or machine check interrupt. */ 57 psw_mask = PSW_KERNEL_BITS | PSW_MASK_WAIT | 58 PSW_MASK_IO | PSW_MASK_EXT | PSW_MASK_MCHECK; 59 clear_cpu_flag(CIF_NOHZ_DELAY); 60 set_cpu_flag(CIF_ENABLED_WAIT); 61 if (smp_cpu_mtid) 62 stcctm(MT_DIAG, smp_cpu_mtid, (u64 *)&idle->mt_cycles_enter); 63 idle->clock_idle_enter = get_tod_clock_fast(); 64 idle->timer_idle_enter = get_cpu_timer(); 65 bpon(); 66 __load_psw_mask(psw_mask); 67 } 68 69 static ssize_t show_idle_count(struct device *dev, 70 struct device_attribute *attr, char *buf) 71 { 72 struct s390_idle_data *idle = &per_cpu(s390_idle, dev->id); 73 74 return sysfs_emit(buf, "%lu\n", READ_ONCE(idle->idle_count)); 75 } 76 DEVICE_ATTR(idle_count, 0444, show_idle_count, NULL); 77 78 static ssize_t show_idle_time(struct device *dev, 79 struct device_attribute *attr, char *buf) 80 { 81 struct s390_idle_data *idle = &per_cpu(s390_idle, dev->id); 82 83 return sysfs_emit(buf, "%lu\n", READ_ONCE(idle->idle_time) >> 12); 84 } 85 DEVICE_ATTR(idle_time_us, 0444, show_idle_time, NULL); 86 87 void arch_cpu_idle_enter(void) 88 { 89 } 90 91 void arch_cpu_idle_exit(void) 92 { 93 } 94 95 void __noreturn arch_cpu_idle_dead(void) 96 { 97 cpu_die(); 98 } 99