[mirror_ubuntu-eoan-kernel.git] / arch / s390 / kernel / idle.c

// 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)
{
	struct s390_idle_data *idle = &per_cpu(s390_idle, dev->id);
	unsigned long long now, idle_time, idle_enter, idle_exit;
	unsigned int seq;

	do {
		now = get_tod_clock();
		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));
	idle_time += idle_enter ? ((idle_exit ? : now) - idle_enter) : 0;
	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;
	unsigned int seq;

	do {
		now = get_tod_clock();
		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));

	return cputime_to_nsecs(idle_enter ? ((idle_exit ?: now) - idle_enter) : 0);
}

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();
}
Commit	Line	Data
b2441318	1	// SPDX-License-Identifier: GPL-2.0
b5f87f15 MS	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/kprobes.h>
	13	#include <linux/notifier.h>
	14	#include <linux/init.h>
	15	#include <linux/cpu.h>
32ef5517	16	#include <linux/sched/cputime.h>
b5f87f15 MS	17	#include <asm/nmi.h>
	18	#include <asm/smp.h>
	19	#include "entry.h"
	20
	21	static DEFINE_PER_CPU(struct s390_idle_data, s390_idle);
	22
7a5388de	23	void enabled_wait(void)
b5f87f15	24	{
0429fbc0	25	struct s390_idle_data *idle = this_cpu_ptr(&s390_idle);
b5f87f15 MS	26	unsigned long long idle_time;
	27	unsigned long psw_mask;
	28
	29	trace_hardirqs_on();
	30
	31	/* Wait for external, I/O or machine check interrupt. */
	32	psw_mask = PSW_KERNEL_BITS \| PSW_MASK_WAIT \| PSW_MASK_DAT \|
	33	PSW_MASK_IO \| PSW_MASK_EXT \| PSW_MASK_MCHECK;
	34	clear_cpu_flag(CIF_NOHZ_DELAY);
	35
	36	/* Call the assembler magic in entry.S */
	37	psw_idle(idle, psw_mask);
	38
200e7c0f HC	39	trace_hardirqs_off();
200e7c0f HC	40
b5f87f15	41	/* Account time spent with enabled wait psw loaded as idle time. */
1ce21804	42	write_seqcount_begin(&idle->seqcount);
b5f87f15 MS	43	idle_time = idle->clock_idle_exit - idle->clock_idle_enter;
	44	idle->clock_idle_enter = idle->clock_idle_exit = 0ULL;
	45	idle->idle_time += idle_time;
	46	idle->idle_count++;
18b43a9b	47	account_idle_time(cputime_to_nsecs(idle_time));
1ce21804	48	write_seqcount_end(&idle->seqcount);
b5f87f15	49	}
7a5388de	50	NOKPROBE_SYMBOL(enabled_wait);
b5f87f15 MS	51
	52	static ssize_t show_idle_count(struct device *dev,
	53	struct device_attribute attr, char buf)
	54	{
	55	struct s390_idle_data *idle = &per_cpu(s390_idle, dev->id);
	56	unsigned long long idle_count;
1ce21804	57	unsigned int seq;
b5f87f15 MS	58
b5f87f15 MS	59	do {
1ce21804	60	seq = read_seqcount_begin(&idle->seqcount);
187b5f41 CB	61	idle_count = READ_ONCE(idle->idle_count);
187b5f41 CB	62	if (READ_ONCE(idle->clock_idle_enter))
b5f87f15	63	idle_count++;
1ce21804	64	} while (read_seqcount_retry(&idle->seqcount, seq));
b5f87f15 MS	65	return sprintf(buf, "%llu\n", idle_count);
	66	}
	67	DEVICE_ATTR(idle_count, 0444, show_idle_count, NULL);
	68
	69	static ssize_t show_idle_time(struct device *dev,
	70	struct device_attribute attr, char buf)
	71	{
	72	struct s390_idle_data *idle = &per_cpu(s390_idle, dev->id);
	73	unsigned long long now, idle_time, idle_enter, idle_exit;
1ce21804	74	unsigned int seq;
b5f87f15 MS	75
	76	do {
	77	now = get_tod_clock();
1ce21804	78	seq = read_seqcount_begin(&idle->seqcount);
187b5f41 CB	79	idle_time = READ_ONCE(idle->idle_time);
	80	idle_enter = READ_ONCE(idle->clock_idle_enter);
	81	idle_exit = READ_ONCE(idle->clock_idle_exit);
1ce21804	82	} while (read_seqcount_retry(&idle->seqcount, seq));
b5f87f15 MS	83	idle_time += idle_enter ? ((idle_exit ? : now) - idle_enter) : 0;
	84	return sprintf(buf, "%llu\n", idle_time >> 12);
	85	}
	86	DEVICE_ATTR(idle_time_us, 0444, show_idle_time, NULL);
	87
42b425b3	88	u64 arch_cpu_idle_time(int cpu)
b5f87f15 MS	89	{
	90	struct s390_idle_data *idle = &per_cpu(s390_idle, cpu);
	91	unsigned long long now, idle_enter, idle_exit;
1ce21804	92	unsigned int seq;
b5f87f15 MS	93
	94	do {
	95	now = get_tod_clock();
1ce21804	96	seq = read_seqcount_begin(&idle->seqcount);
187b5f41 CB	97	idle_enter = READ_ONCE(idle->clock_idle_enter);
187b5f41 CB	98	idle_exit = READ_ONCE(idle->clock_idle_exit);
1ce21804	99	} while (read_seqcount_retry(&idle->seqcount, seq));
42b425b3 FW	100
42b425b3 FW	101	return cputime_to_nsecs(idle_enter ? ((idle_exit ?: now) - idle_enter) : 0);
b5f87f15 MS	102	}
	103
	104	void arch_cpu_idle_enter(void)
	105	{
	106	local_mcck_disable();
	107	}
	108
	109	void arch_cpu_idle(void)
	110	{
	111	if (!test_cpu_flag(CIF_MCCK_PENDING))
	112	/* Halt the cpu and keep track of cpu time accounting. */
	113	enabled_wait();
	114	local_irq_enable();
	115	}
	116
	117	void arch_cpu_idle_exit(void)
	118	{
	119	local_mcck_enable();
	120	if (test_cpu_flag(CIF_MCCK_PENDING))
	121	s390_handle_mcck();
	122	}
	123
	124	void arch_cpu_idle_dead(void)
	125	{
	126	cpu_die();
	127	}