diff options
Diffstat (limited to '')
| -rw-r--r-- | arch/s390/kernel/idle.c | 150 |
1 files changed, 150 insertions, 0 deletions
diff --git a/arch/s390/kernel/idle.c b/arch/s390/kernel/idle.c new file mode 100644 index 000000000..a0da049e7 --- /dev/null +++ b/arch/s390/kernel/idle.c @@ -0,0 +1,150 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Idle functions for s390. + * + * Copyright IBM Corp. 2014 + * + * Author(s): Martin Schwidefsky <schwidefsky@de.ibm.com> + */ + +#include <linux/kernel.h> +#include <linux/kernel_stat.h> +#include <linux/notifier.h> +#include <linux/init.h> +#include <linux/cpu.h> +#include <linux/sched/cputime.h> +#include <trace/events/power.h> +#include <asm/cpu_mf.h> +#include <asm/nmi.h> +#include <asm/smp.h> +#include "entry.h" + +static DEFINE_PER_CPU(struct s390_idle_data, s390_idle); + +void account_idle_time_irq(void) +{ + struct s390_idle_data *idle = this_cpu_ptr(&s390_idle); + u64 cycles_new[8]; + int i; + + clear_cpu_flag(CIF_ENABLED_WAIT); + if (smp_cpu_mtid) { + stcctm(MT_DIAG, smp_cpu_mtid, cycles_new); + for (i = 0; i < smp_cpu_mtid; i++) + this_cpu_add(mt_cycles[i], cycles_new[i] - idle->mt_cycles_enter[i]); + } + + idle->clock_idle_exit = S390_lowcore.int_clock; + idle->timer_idle_exit = S390_lowcore.sys_enter_timer; + + S390_lowcore.steal_timer += idle->clock_idle_enter - S390_lowcore.last_update_clock; + S390_lowcore.last_update_clock = idle->clock_idle_exit; + + S390_lowcore.system_timer += S390_lowcore.last_update_timer - idle->timer_idle_enter; + S390_lowcore.last_update_timer = idle->timer_idle_exit; +} + +void noinstr arch_cpu_idle(void) +{ + struct s390_idle_data *idle = this_cpu_ptr(&s390_idle); + unsigned long idle_time; + unsigned long psw_mask; + + /* Wait for external, I/O or machine check interrupt. */ + psw_mask = PSW_KERNEL_BITS | PSW_MASK_WAIT | PSW_MASK_DAT | + PSW_MASK_IO | PSW_MASK_EXT | PSW_MASK_MCHECK; + clear_cpu_flag(CIF_NOHZ_DELAY); + + /* psw_idle() returns with interrupts disabled. */ + psw_idle(idle, psw_mask); + + /* Account time spent with enabled wait psw loaded as idle time. */ + raw_write_seqcount_begin(&idle->seqcount); + idle_time = idle->clock_idle_exit - idle->clock_idle_enter; + idle->clock_idle_enter = idle->clock_idle_exit = 0ULL; + idle->idle_time += idle_time; + idle->idle_count++; + account_idle_time(cputime_to_nsecs(idle_time)); + raw_write_seqcount_end(&idle->seqcount); + raw_local_irq_enable(); +} + +static ssize_t show_idle_count(struct device *dev, + struct device_attribute *attr, char *buf) +{ + struct s390_idle_data *idle = &per_cpu(s390_idle, dev->id); + unsigned long idle_count; + unsigned int seq; + + do { + seq = read_seqcount_begin(&idle->seqcount); + idle_count = READ_ONCE(idle->idle_count); + if (READ_ONCE(idle->clock_idle_enter)) + idle_count++; + } while (read_seqcount_retry(&idle->seqcount, seq)); + return sprintf(buf, "%lu\n", idle_count); +} +DEVICE_ATTR(idle_count, 0444, show_idle_count, NULL); + +static ssize_t show_idle_time(struct device *dev, + struct device_attribute *attr, char *buf) +{ + unsigned long now, idle_time, idle_enter, idle_exit, in_idle; + struct s390_idle_data *idle = &per_cpu(s390_idle, dev->id); + unsigned int seq; + + do { + seq = read_seqcount_begin(&idle->seqcount); + idle_time = READ_ONCE(idle->idle_time); + idle_enter = READ_ONCE(idle->clock_idle_enter); + idle_exit = READ_ONCE(idle->clock_idle_exit); + } while (read_seqcount_retry(&idle->seqcount, seq)); + in_idle = 0; + now = get_tod_clock(); + if (idle_enter) { + if (idle_exit) { + in_idle = idle_exit - idle_enter; + } else if (now > idle_enter) { + in_idle = now - idle_enter; + } + } + idle_time += in_idle; + return sprintf(buf, "%lu\n", idle_time >> 12); +} +DEVICE_ATTR(idle_time_us, 0444, show_idle_time, NULL); + +u64 arch_cpu_idle_time(int cpu) +{ + struct s390_idle_data *idle = &per_cpu(s390_idle, cpu); + unsigned long now, idle_enter, idle_exit, in_idle; + unsigned int seq; + + do { + seq = read_seqcount_begin(&idle->seqcount); + idle_enter = READ_ONCE(idle->clock_idle_enter); + idle_exit = READ_ONCE(idle->clock_idle_exit); + } while (read_seqcount_retry(&idle->seqcount, seq)); + in_idle = 0; + now = get_tod_clock(); + if (idle_enter) { + if (idle_exit) { + in_idle = idle_exit - idle_enter; + } else if (now > idle_enter) { + in_idle = now - idle_enter; + } + } + return cputime_to_nsecs(in_idle); +} + +void arch_cpu_idle_enter(void) +{ +} + +void arch_cpu_idle_exit(void) +{ +} + +void arch_cpu_idle_dead(void) +{ + cpu_die(); +} |