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// 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 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();
}
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