331 lines
8.5 KiB
C
331 lines
8.5 KiB
C
/*
|
|
* Virtual cpu timer based timer functions.
|
|
*
|
|
* Copyright IBM Corp. 2004, 2012
|
|
* Author(s): Jan Glauber <jan.glauber@de.ibm.com>
|
|
*/
|
|
|
|
#include <linux/kernel_stat.h>
|
|
#include <linux/export.h>
|
|
#include <linux/kernel.h>
|
|
#include <linux/timex.h>
|
|
#include <linux/types.h>
|
|
#include <linux/time.h>
|
|
|
|
#include <asm/cputime.h>
|
|
#include <asm/vtimer.h>
|
|
#include <asm/vtime.h>
|
|
|
|
static void virt_timer_expire(void);
|
|
|
|
static LIST_HEAD(virt_timer_list);
|
|
static DEFINE_SPINLOCK(virt_timer_lock);
|
|
static atomic64_t virt_timer_current;
|
|
static atomic64_t virt_timer_elapsed;
|
|
|
|
static inline u64 get_vtimer(void)
|
|
{
|
|
u64 timer;
|
|
|
|
asm volatile("stpt %0" : "=m" (timer));
|
|
return timer;
|
|
}
|
|
|
|
static inline void set_vtimer(u64 expires)
|
|
{
|
|
u64 timer;
|
|
|
|
asm volatile(
|
|
" stpt %0\n" /* Store current cpu timer value */
|
|
" spt %1" /* Set new value imm. afterwards */
|
|
: "=m" (timer) : "m" (expires));
|
|
S390_lowcore.system_timer += S390_lowcore.last_update_timer - timer;
|
|
S390_lowcore.last_update_timer = expires;
|
|
}
|
|
|
|
static inline int virt_timer_forward(u64 elapsed)
|
|
{
|
|
BUG_ON(!irqs_disabled());
|
|
|
|
if (list_empty(&virt_timer_list))
|
|
return 0;
|
|
elapsed = atomic64_add_return(elapsed, &virt_timer_elapsed);
|
|
return elapsed >= atomic64_read(&virt_timer_current);
|
|
}
|
|
|
|
/*
|
|
* Update process times based on virtual cpu times stored by entry.S
|
|
* to the lowcore fields user_timer, system_timer & steal_clock.
|
|
*/
|
|
static int do_account_vtime(struct task_struct *tsk, int hardirq_offset)
|
|
{
|
|
struct thread_info *ti = task_thread_info(tsk);
|
|
u64 timer, clock, user, system, steal;
|
|
|
|
timer = S390_lowcore.last_update_timer;
|
|
clock = S390_lowcore.last_update_clock;
|
|
asm volatile(
|
|
" stpt %0\n" /* Store current cpu timer value */
|
|
#ifdef CONFIG_HAVE_MARCH_Z9_109_FEATURES
|
|
" stckf %1" /* Store current tod clock value */
|
|
#else
|
|
" stck %1" /* Store current tod clock value */
|
|
#endif
|
|
: "=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_timer += S390_lowcore.last_update_clock - clock;
|
|
|
|
user = S390_lowcore.user_timer - ti->user_timer;
|
|
S390_lowcore.steal_timer -= user;
|
|
ti->user_timer = S390_lowcore.user_timer;
|
|
account_user_time(tsk, user, user);
|
|
|
|
system = S390_lowcore.system_timer - ti->system_timer;
|
|
S390_lowcore.steal_timer -= system;
|
|
ti->system_timer = S390_lowcore.system_timer;
|
|
account_system_time(tsk, hardirq_offset, system, system);
|
|
|
|
steal = S390_lowcore.steal_timer;
|
|
if ((s64) steal > 0) {
|
|
S390_lowcore.steal_timer = 0;
|
|
account_steal_time(steal);
|
|
}
|
|
|
|
return virt_timer_forward(user + system);
|
|
}
|
|
|
|
void vtime_task_switch(struct task_struct *prev)
|
|
{
|
|
struct thread_info *ti;
|
|
|
|
do_account_vtime(prev, 0);
|
|
ti = task_thread_info(prev);
|
|
ti->user_timer = S390_lowcore.user_timer;
|
|
ti->system_timer = S390_lowcore.system_timer;
|
|
ti = task_thread_info(current);
|
|
S390_lowcore.user_timer = ti->user_timer;
|
|
S390_lowcore.system_timer = ti->system_timer;
|
|
}
|
|
|
|
/*
|
|
* In s390, accounting pending user time also implies
|
|
* accounting system time in order to correctly compute
|
|
* the stolen time accounting.
|
|
*/
|
|
void vtime_account_user(struct task_struct *tsk)
|
|
{
|
|
if (do_account_vtime(tsk, HARDIRQ_OFFSET))
|
|
virt_timer_expire();
|
|
}
|
|
|
|
/*
|
|
* Update process times based on virtual cpu times stored by entry.S
|
|
* to the lowcore fields user_timer, system_timer & steal_clock.
|
|
*/
|
|
void vtime_account_irq_enter(struct task_struct *tsk)
|
|
{
|
|
struct thread_info *ti = task_thread_info(tsk);
|
|
u64 timer, system;
|
|
|
|
WARN_ON_ONCE(!irqs_disabled());
|
|
|
|
timer = S390_lowcore.last_update_timer;
|
|
S390_lowcore.last_update_timer = get_vtimer();
|
|
S390_lowcore.system_timer += timer - S390_lowcore.last_update_timer;
|
|
|
|
system = S390_lowcore.system_timer - ti->system_timer;
|
|
S390_lowcore.steal_timer -= system;
|
|
ti->system_timer = S390_lowcore.system_timer;
|
|
account_system_time(tsk, 0, system, system);
|
|
|
|
virt_timer_forward(system);
|
|
}
|
|
EXPORT_SYMBOL_GPL(vtime_account_irq_enter);
|
|
|
|
void vtime_account_system(struct task_struct *tsk)
|
|
__attribute__((alias("vtime_account_irq_enter")));
|
|
EXPORT_SYMBOL_GPL(vtime_account_system);
|
|
|
|
/*
|
|
* 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 *tmp;
|
|
|
|
list_for_each_entry(tmp, head, entry) {
|
|
if (tmp->expires > timer->expires) {
|
|
list_add_tail(&timer->entry, &tmp->entry);
|
|
return;
|
|
}
|
|
}
|
|
list_add_tail(&timer->entry, head);
|
|
}
|
|
|
|
/*
|
|
* Handler for expired virtual CPU timer.
|
|
*/
|
|
static void virt_timer_expire(void)
|
|
{
|
|
struct vtimer_list *timer, *tmp;
|
|
unsigned long elapsed;
|
|
LIST_HEAD(cb_list);
|
|
|
|
/* walk timer list, fire all expired timers */
|
|
spin_lock(&virt_timer_lock);
|
|
elapsed = atomic64_read(&virt_timer_elapsed);
|
|
list_for_each_entry_safe(timer, tmp, &virt_timer_list, entry) {
|
|
if (timer->expires < elapsed)
|
|
/* move expired timer to the callback queue */
|
|
list_move_tail(&timer->entry, &cb_list);
|
|
else
|
|
timer->expires -= elapsed;
|
|
}
|
|
if (!list_empty(&virt_timer_list)) {
|
|
timer = list_first_entry(&virt_timer_list,
|
|
struct vtimer_list, entry);
|
|
atomic64_set(&virt_timer_current, timer->expires);
|
|
}
|
|
atomic64_sub(elapsed, &virt_timer_elapsed);
|
|
spin_unlock(&virt_timer_lock);
|
|
|
|
/* Do callbacks and recharge periodic timers */
|
|
list_for_each_entry_safe(timer, tmp, &cb_list, entry) {
|
|
list_del_init(&timer->entry);
|
|
timer->function(timer->data);
|
|
if (timer->interval) {
|
|
/* Recharge interval timer */
|
|
timer->expires = timer->interval +
|
|
atomic64_read(&virt_timer_elapsed);
|
|
spin_lock(&virt_timer_lock);
|
|
list_add_sorted(timer, &virt_timer_list);
|
|
spin_unlock(&virt_timer_lock);
|
|
}
|
|
}
|
|
}
|
|
|
|
void init_virt_timer(struct vtimer_list *timer)
|
|
{
|
|
timer->function = NULL;
|
|
INIT_LIST_HEAD(&timer->entry);
|
|
}
|
|
EXPORT_SYMBOL(init_virt_timer);
|
|
|
|
static inline int vtimer_pending(struct vtimer_list *timer)
|
|
{
|
|
return !list_empty(&timer->entry);
|
|
}
|
|
|
|
static void internal_add_vtimer(struct vtimer_list *timer)
|
|
{
|
|
if (list_empty(&virt_timer_list)) {
|
|
/* First timer, just program it. */
|
|
atomic64_set(&virt_timer_current, timer->expires);
|
|
atomic64_set(&virt_timer_elapsed, 0);
|
|
list_add(&timer->entry, &virt_timer_list);
|
|
} else {
|
|
/* Update timer against current base. */
|
|
timer->expires += atomic64_read(&virt_timer_elapsed);
|
|
if (likely((s64) timer->expires <
|
|
(s64) atomic64_read(&virt_timer_current)))
|
|
/* The new timer expires before the current timer. */
|
|
atomic64_set(&virt_timer_current, timer->expires);
|
|
/* Insert new timer into the list. */
|
|
list_add_sorted(timer, &virt_timer_list);
|
|
}
|
|
}
|
|
|
|
static void __add_vtimer(struct vtimer_list *timer, int periodic)
|
|
{
|
|
unsigned long flags;
|
|
|
|
timer->interval = periodic ? timer->expires : 0;
|
|
spin_lock_irqsave(&virt_timer_lock, flags);
|
|
internal_add_vtimer(timer);
|
|
spin_unlock_irqrestore(&virt_timer_lock, flags);
|
|
}
|
|
|
|
/*
|
|
* add_virt_timer - add an oneshot virtual CPU timer
|
|
*/
|
|
void add_virt_timer(struct vtimer_list *timer)
|
|
{
|
|
__add_vtimer(timer, 0);
|
|
}
|
|
EXPORT_SYMBOL(add_virt_timer);
|
|
|
|
/*
|
|
* add_virt_timer_int - add an interval virtual CPU timer
|
|
*/
|
|
void add_virt_timer_periodic(struct vtimer_list *timer)
|
|
{
|
|
__add_vtimer(timer, 1);
|
|
}
|
|
EXPORT_SYMBOL(add_virt_timer_periodic);
|
|
|
|
static int __mod_vtimer(struct vtimer_list *timer, u64 expires, int periodic)
|
|
{
|
|
unsigned long flags;
|
|
int rc;
|
|
|
|
BUG_ON(!timer->function);
|
|
|
|
if (timer->expires == expires && vtimer_pending(timer))
|
|
return 1;
|
|
spin_lock_irqsave(&virt_timer_lock, flags);
|
|
rc = vtimer_pending(timer);
|
|
if (rc)
|
|
list_del_init(&timer->entry);
|
|
timer->interval = periodic ? expires : 0;
|
|
timer->expires = expires;
|
|
internal_add_vtimer(timer);
|
|
spin_unlock_irqrestore(&virt_timer_lock, flags);
|
|
return rc;
|
|
}
|
|
|
|
/*
|
|
* returns whether it has modified a pending timer (1) or not (0)
|
|
*/
|
|
int mod_virt_timer(struct vtimer_list *timer, u64 expires)
|
|
{
|
|
return __mod_vtimer(timer, expires, 0);
|
|
}
|
|
EXPORT_SYMBOL(mod_virt_timer);
|
|
|
|
/*
|
|
* returns whether it has modified a pending timer (1) or not (0)
|
|
*/
|
|
int mod_virt_timer_periodic(struct vtimer_list *timer, u64 expires)
|
|
{
|
|
return __mod_vtimer(timer, expires, 1);
|
|
}
|
|
EXPORT_SYMBOL(mod_virt_timer_periodic);
|
|
|
|
/*
|
|
* 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;
|
|
|
|
if (!vtimer_pending(timer))
|
|
return 0;
|
|
spin_lock_irqsave(&virt_timer_lock, flags);
|
|
list_del_init(&timer->entry);
|
|
spin_unlock_irqrestore(&virt_timer_lock, flags);
|
|
return 1;
|
|
}
|
|
EXPORT_SYMBOL(del_virt_timer);
|
|
|
|
/*
|
|
* Start the virtual CPU timer on the current CPU.
|
|
*/
|
|
void vtime_init(void)
|
|
{
|
|
/* set initial cpu timer */
|
|
set_vtimer(VTIMER_MAX_SLICE);
|
|
}
|