1 files changed, 565 insertions, 0 deletions
diff --git a/arch/s390/kernel/vtime.c b/arch/s390/kernel/vtime.c
new file mode 100644
index 00000000000..bb6cf02418a
--- /dev/null
+++ b/arch/s390/kernel/vtime.c
@@ -0,0 +1,565 @@
+/*
+ *  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/config.h>
+#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>
+
+#define VTIMER_MAGIC (TIMER_MAGIC + 1)
+static ext_int_info_t ext_int_info_timer;
+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_user_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_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());
+	set_vtimer(vt_list->idle);
+}
+
+static void stop_cpu_timer(void)
+{
+	__u64 done;
+	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 progress */
+	asm volatile ("STPT %0" : "=m" (done));
+
+	/*
+	 * If done is negative we do not stop the CPU timer
+	 * because we will get instantly an interrupt that
+	 * will start the CPU timer again.
+	 */
+	if (done & 1LL<<63)
+		return;
+	else
+		vt_list->offset += vt_list->to_expire - done;
+
+	/* save the actual expire value */
+	vt_list->idle = done;
+
+	/*
+	 * 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 pt_regs *regs)
+{
+	struct vtimer_queue *vt_list;
+	struct vtimer_list *event, *tmp;
+	void (*fn)(unsigned long, struct pt_regs*);
+	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, regs);
+
+		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(struct pt_regs *regs, __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, regs);
+
+	/* 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->magic = VTIMER_MAGIC;
+	timer->function = NULL;
+	INIT_LIST_HEAD(&timer->entry);
+	spin_lock_init(&timer->lock);
+}
+EXPORT_SYMBOL(init_virt_timer);
+
+static inline int check_vtimer(struct vtimer_list *timer)
+{
+	if (timer->magic != VTIMER_MAGIC)
+		return -EINVAL;
+	return 0;
+}
+
+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 aquired in prepare_vtimer or mod_virt_timer() */
+	put_cpu();
+}
+
+static inline int prepare_vtimer(struct vtimer_list *timer)
+{
+	if (check_vtimer(timer) || !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 (check_vtimer(timer) || !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;
+
+	if (check_vtimer(timer)) {
+		printk("del_virt_timer: timer not initialized\n");
+		return -EINVAL;
+	}
+
+	/* 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;
+	unsigned long cr0;
+
+	/* 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));
+	__ctl_store(cr0, 0, 0);
+	cr0 |= 0x400;
+	__ctl_load(cr0, 0, 0);
+
+	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");
+
+	init_cpu_vtimer();
+}
+