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/sched/stat.h> 13 #include <linux/notifier.h> 14 #include <linux/init.h> 15 #include <linux/cpu.h> 16 #include <linux/export.h> 17 #include <trace/events/power.h> 18 #include <asm/cpu_mf.h> 19 #include <asm/cputime.h> 20 #include <asm/idle.h> 21 #include <asm/nmi.h> 22 #include <asm/smp.h> 23 24 DEFINE_PER_CPU(struct s390_idle_data, s390_idle); 25 26 static __always_inline void __account_idle_time_irq(void) 27 { 28 struct s390_idle_data *idle = this_cpu_ptr(&s390_idle); 29 unsigned long idle_time; 30 31 idle_time = idle->clock_idle_exit.tod - idle->clock_idle_enter.tod; 32 account_idle_time(cputime_to_nsecs(idle_time)); 33 } 34 35 static __always_inline void __account_idle_time_setup(void) 36 { 37 struct s390_idle_data *idle = this_cpu_ptr(&s390_idle); 38 39 store_tod_clock_ext(&idle->clock_idle_enter); 40 idle->timer_idle_enter = get_cpu_timer(); 41 idle->clock_idle_exit = idle->clock_idle_enter; 42 } 43 44 #ifdef CONFIG_NO_HZ_COMMON 45 46 static u64 arch_cpu_in_idle_time(int cpu) 47 { 48 struct s390_idle_data *idle = &per_cpu(s390_idle, cpu); 49 union tod_clock now; 50 u64 idle_time; 51 52 if (!idle->in_idle) 53 return 0; 54 store_tod_clock_ext(&now); 55 if (tod_after(idle->clock_idle_exit.tod, idle->clock_idle_enter.tod)) 56 idle_time = idle->clock_idle_exit.tod - idle->clock_idle_enter.tod; 57 else 58 idle_time = now.tod - idle->clock_idle_enter.tod; 59 return cputime_to_nsecs(idle_time); 60 } 61 62 static u64 arch_cpu_idle_time(int cpu, enum cpu_usage_stat idx, bool compute_delta) 63 { 64 struct kernel_cpustat *kc = &kcpustat_cpu(cpu); 65 u64 *cpustat = kc->cpustat; 66 unsigned int seq; 67 u64 idle_time; 68 69 /* 70 * The open coded seqcount writer in entry.S relies on the 71 * raw counting mechanism without any writer protection. 72 */ 73 typecheck(typeof(kc->idle_sleeptime_seq), seqcount_t); 74 do { 75 seq = read_seqcount_begin(&kc->idle_sleeptime_seq); 76 idle_time = cpustat[idx]; 77 if (compute_delta) 78 idle_time += arch_cpu_in_idle_time(cpu); 79 } while (read_seqcount_retry(&kc->idle_sleeptime_seq, seq)); 80 return idle_time; 81 } 82 83 u64 arch_kcpustat_field_idle(int cpu) 84 { 85 return arch_cpu_idle_time(cpu, CPUTIME_IDLE, !nr_iowait_cpu(cpu)); 86 } 87 EXPORT_SYMBOL_GPL(arch_kcpustat_field_idle); 88 89 u64 arch_kcpustat_field_iowait(int cpu) 90 { 91 return arch_cpu_idle_time(cpu, CPUTIME_IOWAIT, nr_iowait_cpu(cpu)); 92 } 93 EXPORT_SYMBOL_GPL(arch_kcpustat_field_iowait); 94 95 void account_idle_time_irq(void) 96 { 97 struct s390_idle_data *idle = this_cpu_ptr(&s390_idle); 98 struct kernel_cpustat *kc = kcpustat_this_cpu; 99 100 write_seqcount_begin(&kc->idle_sleeptime_seq); 101 idle->in_idle = false; 102 __account_idle_time_irq(); 103 write_seqcount_end(&kc->idle_sleeptime_seq); 104 } 105 106 static __always_inline void account_idle_time_setup(void) 107 { 108 struct s390_idle_data *idle = this_cpu_ptr(&s390_idle); 109 struct kernel_cpustat *kc = kcpustat_this_cpu; 110 111 raw_write_seqcount_begin(&kc->idle_sleeptime_seq); 112 idle->in_idle = true; 113 __account_idle_time_setup(); 114 raw_write_seqcount_end(&kc->idle_sleeptime_seq); 115 } 116 117 #else /* CONFIG_NO_HZ_COMMON */ 118 119 void account_idle_time_irq(void) 120 { 121 __account_idle_time_irq(); 122 } 123 124 static __always_inline void account_idle_time_setup(void) 125 { 126 __account_idle_time_setup(); 127 } 128 129 #endif /* CONFIG_NO_HZ_COMMON */ 130 131 void noinstr arch_cpu_idle(void) 132 { 133 struct s390_idle_data *idle = this_cpu_ptr(&s390_idle); 134 unsigned long psw_mask; 135 136 /* Wait for external, I/O or machine check interrupt. */ 137 psw_mask = PSW_KERNEL_BITS | PSW_MASK_WAIT | 138 PSW_MASK_IO | PSW_MASK_EXT | PSW_MASK_MCHECK; 139 clear_cpu_flag(CIF_NOHZ_DELAY); 140 set_cpu_flag(CIF_ENABLED_WAIT); 141 if (smp_cpu_mtid) 142 stcctm(MT_DIAG, smp_cpu_mtid, (u64 *)&idle->mt_cycles_enter); 143 account_idle_time_setup(); 144 bpon(); 145 __load_psw_mask(psw_mask); 146 } 147 148 void arch_cpu_idle_enter(void) 149 { 150 } 151 152 void arch_cpu_idle_exit(void) 153 { 154 } 155 156 void __noreturn arch_cpu_idle_dead(void) 157 { 158 cpu_die(); 159 } 160