Initial import

1 files changed, 379 insertions, 0 deletions

diff --git a/arch/s390/kernel/vtime.c b/arch/s390/kernel/vtime.c
new file mode 100644
index 000000000..e53d3595a
--- /dev/null
+++ b/arch/s390/kernel/vtime.c
@@ -0,0 +1,379 @@
+/*
+ *    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>
+#include <asm/cpu_mf.h>
+#include <asm/smp.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 DEFINE_PER_CPU(u64, mt_cycles[32]);
+static DEFINE_PER_CPU(u64, mt_scaling_mult) = { 1 };
+static DEFINE_PER_CPU(u64, mt_scaling_div) = { 1 };
+
+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;
+	u64 user_scaled, system_scaled;
+	int i;
+
+	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;
+
+	/* Do MT utilization calculation */
+	if (smp_cpu_mtid) {
+		u64 cycles_new[32], *cycles_old;
+		u64 delta, mult, div;
+
+		cycles_old = this_cpu_ptr(mt_cycles);
+		if (stcctm5(smp_cpu_mtid + 1, cycles_new) < 2) {
+			mult = div = 0;
+			for (i = 0; i <= smp_cpu_mtid; i++) {
+				delta = cycles_new[i] - cycles_old[i];
+				mult += delta;
+				div += (i + 1) * delta;
+			}
+			if (mult > 0) {
+				/* Update scaling factor */
+				__this_cpu_write(mt_scaling_mult, mult);
+				__this_cpu_write(mt_scaling_div, div);
+				memcpy(cycles_old, cycles_new,
+				       sizeof(u64) * (smp_cpu_mtid + 1));
+			}
+		}
+	}
+
+	user = S390_lowcore.user_timer - ti->user_timer;
+	S390_lowcore.steal_timer -= user;
+	ti->user_timer = S390_lowcore.user_timer;
+
+	system = S390_lowcore.system_timer - ti->system_timer;
+	S390_lowcore.steal_timer -= system;
+	ti->system_timer = S390_lowcore.system_timer;
+
+	user_scaled = user;
+	system_scaled = system;
+	/* Do MT utilization scaling */
+	if (smp_cpu_mtid) {
+		u64 mult = __this_cpu_read(mt_scaling_mult);
+		u64 div = __this_cpu_read(mt_scaling_div);
+
+		user_scaled = (user_scaled * mult) / div;
+		system_scaled = (system_scaled * mult) / div;
+	}
+	account_user_time(tsk, user, user_scaled);
+	account_system_time(tsk, hardirq_offset, system, system_scaled);
+
+	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, system_scaled;
+
+	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;
+	system_scaled = system;
+	/* Do MT utilization scaling */
+	if (smp_cpu_mtid) {
+		u64 mult = __this_cpu_read(mt_scaling_mult);
+		u64 div = __this_cpu_read(mt_scaling_div);
+
+		system_scaled = (system_scaled * mult) / div;
+	}
+	account_system_time(tsk, 0, system, system_scaled);
+
+	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);
+}