linux/arch/s390/kernel/idle.c
Sven Schnelle fa2ae4a377 s390/idle: Rewrite psw_idle() in C
To ease maintenance and further enhancements, convert
the psw_idle() function to C.

Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Sven Schnelle <svens@linux.ibm.com>
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>
2024-05-14 13:37:07 +02:00

99 lines
2.6 KiB
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/notifier.h>
#include <linux/init.h>
#include <linux/cpu.h>
#include <trace/events/power.h>
#include <asm/cpu_mf.h>
#include <asm/cputime.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);
unsigned long idle_time;
u64 cycles_new[8];
int i;
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_time = S390_lowcore.int_clock - idle->clock_idle_enter;
S390_lowcore.steal_timer += idle->clock_idle_enter - S390_lowcore.last_update_clock;
S390_lowcore.last_update_clock = S390_lowcore.int_clock;
S390_lowcore.system_timer += S390_lowcore.last_update_timer - idle->timer_idle_enter;
S390_lowcore.last_update_timer = S390_lowcore.sys_enter_timer;
/* Account time spent with enabled wait psw loaded as idle time. */
WRITE_ONCE(idle->idle_time, READ_ONCE(idle->idle_time) + idle_time);
WRITE_ONCE(idle->idle_count, READ_ONCE(idle->idle_count) + 1);
account_idle_time(cputime_to_nsecs(idle_time));
}
void noinstr arch_cpu_idle(void)
{
struct s390_idle_data *idle = this_cpu_ptr(&s390_idle);
unsigned long psw_mask;
/* Wait for external, I/O or machine check interrupt. */
psw_mask = PSW_KERNEL_BITS | PSW_MASK_WAIT |
PSW_MASK_IO | PSW_MASK_EXT | PSW_MASK_MCHECK;
clear_cpu_flag(CIF_NOHZ_DELAY);
set_cpu_flag(CIF_ENABLED_WAIT);
if (smp_cpu_mtid)
stcctm(MT_DIAG, smp_cpu_mtid, (u64 *)&idle->mt_cycles_enter);
idle->clock_idle_enter = get_tod_clock_fast();
idle->timer_idle_enter = get_cpu_timer();
bpon();
__load_psw_mask(psw_mask);
}
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);
return sysfs_emit(buf, "%lu\n", READ_ONCE(idle->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);
return sysfs_emit(buf, "%lu\n", READ_ONCE(idle->idle_time) >> 12);
}
DEVICE_ATTR(idle_time_us, 0444, show_idle_time, NULL);
void arch_cpu_idle_enter(void)
{
}
void arch_cpu_idle_exit(void)
{
}
void __noreturn arch_cpu_idle_dead(void)
{
cpu_die();
}