diff options
Diffstat (limited to 'arch/s390/kernel/idle.c')
| -rw-r--r-- | arch/s390/kernel/idle.c | 142 |
1 files changed, 142 insertions, 0 deletions
diff --git a/arch/s390/kernel/idle.c b/arch/s390/kernel/idle.c new file mode 100644 index 000000000..8f8456816 --- /dev/null +++ b/arch/s390/kernel/idle.c @@ -0,0 +1,142 @@ +// 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/kprobes.h> +#include <linux/notifier.h> +#include <linux/init.h> +#include <linux/cpu.h> +#include <linux/sched/cputime.h> +#include <asm/nmi.h> +#include <asm/smp.h> +#include "entry.h" + +static DEFINE_PER_CPU(struct s390_idle_data, s390_idle); + +void enabled_wait(void) +{ + struct s390_idle_data *idle = this_cpu_ptr(&s390_idle); + unsigned long long idle_time; + unsigned long psw_mask; + + trace_hardirqs_on(); + + /* 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); + + /* Call the assembler magic in entry.S */ + psw_idle(idle, psw_mask); + + trace_hardirqs_off(); + + /* Account time spent with enabled wait psw loaded as idle time. */ + 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)); + write_seqcount_end(&idle->seqcount); +} +NOKPROBE_SYMBOL(enabled_wait); + +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 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, "%llu\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 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, "%llu\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 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) +{ + local_mcck_disable(); +} + +void arch_cpu_idle(void) +{ + if (!test_cpu_flag(CIF_MCCK_PENDING)) + /* Halt the cpu and keep track of cpu time accounting. */ + enabled_wait(); + local_irq_enable(); +} + +void arch_cpu_idle_exit(void) +{ + local_mcck_enable(); + if (test_cpu_flag(CIF_MCCK_PENDING)) + s390_handle_mcck(); +} + +void arch_cpu_idle_dead(void) +{ + cpu_die(); +} |