blob: 9d5b02801b460882cde4928b2a87d2c905f6f0b6 [file] [log] [blame]
/*
* arch/s390/kernel/vtime.c
* Virtual cpu timer based timer functions.
*
* S390 version
* Copyright (C) 2004 IBM Deutschland Entwicklung GmbH, IBM Corporation
* Author(s): Jan Glauber <jan.glauber@de.ibm.com>
*/
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/time.h>
#include <linux/delay.h>
#include <linux/init.h>
#include <linux/smp.h>
#include <linux/types.h>
#include <linux/timex.h>
#include <linux/notifier.h>
#include <linux/kernel_stat.h>
#include <linux/rcupdate.h>
#include <linux/posix-timers.h>
#include <asm/s390_ext.h>
#include <asm/timer.h>
#include <asm/irq_regs.h>
static ext_int_info_t ext_int_info_timer;
static DEFINE_PER_CPU(struct vtimer_queue, virt_cpu_timer);
#ifdef CONFIG_VIRT_CPU_ACCOUNTING
/*
* Update process times based on virtual cpu times stored by entry.S
* to the lowcore fields user_timer, system_timer & steal_clock.
*/
void account_tick_vtime(struct task_struct *tsk)
{
cputime_t cputime;
__u64 timer, clock;
int rcu_user_flag;
timer = S390_lowcore.last_update_timer;
clock = S390_lowcore.last_update_clock;
asm volatile (" STPT %0\n" /* Store current cpu timer value */
" STCK %1" /* Store current tod clock value */
: "=m" (S390_lowcore.last_update_timer),
"=m" (S390_lowcore.last_update_clock) );
S390_lowcore.system_timer += timer - S390_lowcore.last_update_timer;
S390_lowcore.steal_clock += S390_lowcore.last_update_clock - clock;
cputime = S390_lowcore.user_timer >> 12;
rcu_user_flag = cputime != 0;
S390_lowcore.user_timer -= cputime << 12;
S390_lowcore.steal_clock -= cputime << 12;
account_user_time(tsk, cputime);
cputime = S390_lowcore.system_timer >> 12;
S390_lowcore.system_timer -= cputime << 12;
S390_lowcore.steal_clock -= cputime << 12;
account_system_time(tsk, HARDIRQ_OFFSET, cputime);
cputime = S390_lowcore.steal_clock;
if ((__s64) cputime > 0) {
cputime >>= 12;
S390_lowcore.steal_clock -= cputime << 12;
account_steal_time(tsk, cputime);
}
run_local_timers();
if (rcu_pending(smp_processor_id()))
rcu_check_callbacks(smp_processor_id(), rcu_user_flag);
scheduler_tick();
run_posix_cpu_timers(tsk);
}
/*
* Update process times based on virtual cpu times stored by entry.S
* to the lowcore fields user_timer, system_timer & steal_clock.
*/
void account_vtime(struct task_struct *tsk)
{
cputime_t cputime;
__u64 timer;
timer = S390_lowcore.last_update_timer;
asm volatile (" STPT %0" /* Store current cpu timer value */
: "=m" (S390_lowcore.last_update_timer) );
S390_lowcore.system_timer += timer - S390_lowcore.last_update_timer;
cputime = S390_lowcore.user_timer >> 12;
S390_lowcore.user_timer -= cputime << 12;
S390_lowcore.steal_clock -= cputime << 12;
account_user_time(tsk, cputime);
cputime = S390_lowcore.system_timer >> 12;
S390_lowcore.system_timer -= cputime << 12;
S390_lowcore.steal_clock -= cputime << 12;
account_system_time(tsk, 0, cputime);
}
/*
* Update process times based on virtual cpu times stored by entry.S
* to the lowcore fields user_timer, system_timer & steal_clock.
*/
void account_system_vtime(struct task_struct *tsk)
{
cputime_t cputime;
__u64 timer;
timer = S390_lowcore.last_update_timer;
asm volatile (" STPT %0" /* Store current cpu timer value */
: "=m" (S390_lowcore.last_update_timer) );
S390_lowcore.system_timer += timer - S390_lowcore.last_update_timer;
cputime = S390_lowcore.system_timer >> 12;
S390_lowcore.system_timer -= cputime << 12;
S390_lowcore.steal_clock -= cputime << 12;
account_system_time(tsk, 0, cputime);
}
static inline void set_vtimer(__u64 expires)
{
__u64 timer;
asm volatile (" STPT %0\n" /* Store current cpu timer value */
" SPT %1" /* Set new value immediatly afterwards */
: "=m" (timer) : "m" (expires) );
S390_lowcore.system_timer += S390_lowcore.last_update_timer - timer;
S390_lowcore.last_update_timer = expires;
/* store expire time for this CPU timer */
per_cpu(virt_cpu_timer, smp_processor_id()).to_expire = expires;
}
#else
static inline void set_vtimer(__u64 expires)
{
S390_lowcore.last_update_timer = expires;
asm volatile ("SPT %0" : : "m" (S390_lowcore.last_update_timer));
/* store expire time for this CPU timer */
per_cpu(virt_cpu_timer, smp_processor_id()).to_expire = expires;
}
#endif
static void start_cpu_timer(void)
{
struct vtimer_queue *vt_list;
vt_list = &per_cpu(virt_cpu_timer, smp_processor_id());
/* CPU timer interrupt is pending, don't reprogramm it */
if (vt_list->idle & 1LL<<63)
return;
if (!list_empty(&vt_list->list))
set_vtimer(vt_list->idle);
}
static void stop_cpu_timer(void)
{
struct vtimer_queue *vt_list;
vt_list = &per_cpu(virt_cpu_timer, smp_processor_id());
/* nothing to do */
if (list_empty(&vt_list->list)) {
vt_list->idle = VTIMER_MAX_SLICE;
goto fire;
}
/* store the actual expire value */
asm volatile ("STPT %0" : "=m" (vt_list->idle));
/*
* If the CPU timer is negative we don't reprogramm
* it because we will get instantly an interrupt.
*/
if (vt_list->idle & 1LL<<63)
return;
vt_list->offset += vt_list->to_expire - vt_list->idle;
/*
* We cannot halt the CPU timer, we just write a value that
* nearly never expires (only after 71 years) and re-write
* the stored expire value if we continue the timer
*/
fire:
set_vtimer(VTIMER_MAX_SLICE);
}
/*
* Sorted add to a list. List is linear searched until first bigger
* element is found.
*/
static void list_add_sorted(struct vtimer_list *timer, struct list_head *head)
{
struct vtimer_list *event;
list_for_each_entry(event, head, entry) {
if (event->expires > timer->expires) {
list_add_tail(&timer->entry, &event->entry);
return;
}
}
list_add_tail(&timer->entry, head);
}
/*
* Do the callback functions of expired vtimer events.
* Called from within the interrupt handler.
*/
static void do_callbacks(struct list_head *cb_list)
{
struct vtimer_queue *vt_list;
struct vtimer_list *event, *tmp;
void (*fn)(unsigned long);
unsigned long data;
if (list_empty(cb_list))
return;
vt_list = &per_cpu(virt_cpu_timer, smp_processor_id());
list_for_each_entry_safe(event, tmp, cb_list, entry) {
fn = event->function;
data = event->data;
fn(data);
if (!event->interval)
/* delete one shot timer */
list_del_init(&event->entry);
else {
/* move interval timer back to list */
spin_lock(&vt_list->lock);
list_del_init(&event->entry);
list_add_sorted(event, &vt_list->list);
spin_unlock(&vt_list->lock);
}
}
}
/*
* Handler for the virtual CPU timer.
*/
static void do_cpu_timer_interrupt(__u16 error_code)
{
int cpu;
__u64 next, delta;
struct vtimer_queue *vt_list;
struct vtimer_list *event, *tmp;
struct list_head *ptr;
/* the callback queue */
struct list_head cb_list;
INIT_LIST_HEAD(&cb_list);
cpu = smp_processor_id();
vt_list = &per_cpu(virt_cpu_timer, cpu);
/* walk timer list, fire all expired events */
spin_lock(&vt_list->lock);
if (vt_list->to_expire < VTIMER_MAX_SLICE)
vt_list->offset += vt_list->to_expire;
list_for_each_entry_safe(event, tmp, &vt_list->list, entry) {
if (event->expires > vt_list->offset)
/* found first unexpired event, leave */
break;
/* re-charge interval timer, we have to add the offset */
if (event->interval)
event->expires = event->interval + vt_list->offset;
/* move expired timer to the callback queue */
list_move_tail(&event->entry, &cb_list);
}
spin_unlock(&vt_list->lock);
do_callbacks(&cb_list);
/* next event is first in list */
spin_lock(&vt_list->lock);
if (!list_empty(&vt_list->list)) {
ptr = vt_list->list.next;
event = list_entry(ptr, struct vtimer_list, entry);
next = event->expires - vt_list->offset;
/* add the expired time from this interrupt handler
* and the callback functions
*/
asm volatile ("STPT %0" : "=m" (delta));
delta = 0xffffffffffffffffLL - delta + 1;
vt_list->offset += delta;
next -= delta;
} else {
vt_list->offset = 0;
next = VTIMER_MAX_SLICE;
}
spin_unlock(&vt_list->lock);
set_vtimer(next);
}
void init_virt_timer(struct vtimer_list *timer)
{
timer->function = NULL;
INIT_LIST_HEAD(&timer->entry);
spin_lock_init(&timer->lock);
}
EXPORT_SYMBOL(init_virt_timer);
static inline int vtimer_pending(struct vtimer_list *timer)
{
return (!list_empty(&timer->entry));
}
/*
* this function should only run on the specified CPU
*/
static void internal_add_vtimer(struct vtimer_list *timer)
{
unsigned long flags;
__u64 done;
struct vtimer_list *event;
struct vtimer_queue *vt_list;
vt_list = &per_cpu(virt_cpu_timer, timer->cpu);
spin_lock_irqsave(&vt_list->lock, flags);
if (timer->cpu != smp_processor_id())
printk("internal_add_vtimer: BUG, running on wrong CPU");
/* if list is empty we only have to set the timer */
if (list_empty(&vt_list->list)) {
/* reset the offset, this may happen if the last timer was
* just deleted by mod_virt_timer and the interrupt
* didn't happen until here
*/
vt_list->offset = 0;
goto fire;
}
/* save progress */
asm volatile ("STPT %0" : "=m" (done));
/* calculate completed work */
done = vt_list->to_expire - done + vt_list->offset;
vt_list->offset = 0;
list_for_each_entry(event, &vt_list->list, entry)
event->expires -= done;
fire:
list_add_sorted(timer, &vt_list->list);
/* get first element, which is the next vtimer slice */
event = list_entry(vt_list->list.next, struct vtimer_list, entry);
set_vtimer(event->expires);
spin_unlock_irqrestore(&vt_list->lock, flags);
/* release CPU acquired in prepare_vtimer or mod_virt_timer() */
put_cpu();
}
static inline int prepare_vtimer(struct vtimer_list *timer)
{
if (!timer->function) {
printk("add_virt_timer: uninitialized timer\n");
return -EINVAL;
}
if (!timer->expires || timer->expires > VTIMER_MAX_SLICE) {
printk("add_virt_timer: invalid timer expire value!\n");
return -EINVAL;
}
if (vtimer_pending(timer)) {
printk("add_virt_timer: timer pending\n");
return -EBUSY;
}
timer->cpu = get_cpu();
return 0;
}
/*
* add_virt_timer - add an oneshot virtual CPU timer
*/
void add_virt_timer(void *new)
{
struct vtimer_list *timer;
timer = (struct vtimer_list *)new;
if (prepare_vtimer(timer) < 0)
return;
timer->interval = 0;
internal_add_vtimer(timer);
}
EXPORT_SYMBOL(add_virt_timer);
/*
* add_virt_timer_int - add an interval virtual CPU timer
*/
void add_virt_timer_periodic(void *new)
{
struct vtimer_list *timer;
timer = (struct vtimer_list *)new;
if (prepare_vtimer(timer) < 0)
return;
timer->interval = timer->expires;
internal_add_vtimer(timer);
}
EXPORT_SYMBOL(add_virt_timer_periodic);
/*
* If we change a pending timer the function must be called on the CPU
* where the timer is running on, e.g. by smp_call_function_on()
*
* The original mod_timer adds the timer if it is not pending. For compatibility
* we do the same. The timer will be added on the current CPU as a oneshot timer.
*
* returns whether it has modified a pending timer (1) or not (0)
*/
int mod_virt_timer(struct vtimer_list *timer, __u64 expires)
{
struct vtimer_queue *vt_list;
unsigned long flags;
int cpu;
if (!timer->function) {
printk("mod_virt_timer: uninitialized timer\n");
return -EINVAL;
}
if (!expires || expires > VTIMER_MAX_SLICE) {
printk("mod_virt_timer: invalid expire range\n");
return -EINVAL;
}
/*
* This is a common optimization triggered by the
* networking code - if the timer is re-modified
* to be the same thing then just return:
*/
if (timer->expires == expires && vtimer_pending(timer))
return 1;
cpu = get_cpu();
vt_list = &per_cpu(virt_cpu_timer, cpu);
/* disable interrupts before test if timer is pending */
spin_lock_irqsave(&vt_list->lock, flags);
/* if timer isn't pending add it on the current CPU */
if (!vtimer_pending(timer)) {
spin_unlock_irqrestore(&vt_list->lock, flags);
/* we do not activate an interval timer with mod_virt_timer */
timer->interval = 0;
timer->expires = expires;
timer->cpu = cpu;
internal_add_vtimer(timer);
return 0;
}
/* check if we run on the right CPU */
if (timer->cpu != cpu) {
printk("mod_virt_timer: running on wrong CPU, check your code\n");
spin_unlock_irqrestore(&vt_list->lock, flags);
put_cpu();
return -EINVAL;
}
list_del_init(&timer->entry);
timer->expires = expires;
/* also change the interval if we have an interval timer */
if (timer->interval)
timer->interval = expires;
/* the timer can't expire anymore so we can release the lock */
spin_unlock_irqrestore(&vt_list->lock, flags);
internal_add_vtimer(timer);
return 1;
}
EXPORT_SYMBOL(mod_virt_timer);
/*
* delete a virtual timer
*
* returns whether the deleted timer was pending (1) or not (0)
*/
int del_virt_timer(struct vtimer_list *timer)
{
unsigned long flags;
struct vtimer_queue *vt_list;
/* check if timer is pending */
if (!vtimer_pending(timer))
return 0;
vt_list = &per_cpu(virt_cpu_timer, timer->cpu);
spin_lock_irqsave(&vt_list->lock, flags);
/* we don't interrupt a running timer, just let it expire! */
list_del_init(&timer->entry);
/* last timer removed */
if (list_empty(&vt_list->list)) {
vt_list->to_expire = 0;
vt_list->offset = 0;
}
spin_unlock_irqrestore(&vt_list->lock, flags);
return 1;
}
EXPORT_SYMBOL(del_virt_timer);
/*
* Start the virtual CPU timer on the current CPU.
*/
void init_cpu_vtimer(void)
{
struct vtimer_queue *vt_list;
/* kick the virtual timer */
S390_lowcore.exit_timer = VTIMER_MAX_SLICE;
S390_lowcore.last_update_timer = VTIMER_MAX_SLICE;
asm volatile ("SPT %0" : : "m" (S390_lowcore.last_update_timer));
asm volatile ("STCK %0" : "=m" (S390_lowcore.last_update_clock));
/* enable cpu timer interrupts */
__ctl_set_bit(0,10);
vt_list = &per_cpu(virt_cpu_timer, smp_processor_id());
INIT_LIST_HEAD(&vt_list->list);
spin_lock_init(&vt_list->lock);
vt_list->to_expire = 0;
vt_list->offset = 0;
vt_list->idle = 0;
}
static int vtimer_idle_notify(struct notifier_block *self,
unsigned long action, void *hcpu)
{
switch (action) {
case CPU_IDLE:
stop_cpu_timer();
break;
case CPU_NOT_IDLE:
start_cpu_timer();
break;
}
return NOTIFY_OK;
}
static struct notifier_block vtimer_idle_nb = {
.notifier_call = vtimer_idle_notify,
};
void __init vtime_init(void)
{
/* request the cpu timer external interrupt */
if (register_early_external_interrupt(0x1005, do_cpu_timer_interrupt,
&ext_int_info_timer) != 0)
panic("Couldn't request external interrupt 0x1005");
if (register_idle_notifier(&vtimer_idle_nb))
panic("Couldn't register idle notifier");
/* Enable cpu timer interrupts on the boot cpu. */
init_cpu_vtimer();
}