1 files changed, 401 insertions, 0 deletions
diff --git a/arch/s390/kernel/vtime.c b/arch/s390/kernel/vtime.c
new file mode 100644
index 00000000..737d50ca
--- /dev/null
+++ b/arch/s390/kernel/vtime.c
@@ -0,0 +1,401 @@
+/*
+ *    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/notifier.h>
+#include <linux/kprobes.h>
+#include <linux/export.h>
+#include <linux/kernel.h>
+#include <linux/timex.h>
+#include <linux/types.h>
+#include <linux/time.h>
+#include <linux/cpu.h>
+#include <linux/smp.h>
+
+#include <asm/irq_regs.h>
+#include <asm/cputime.h>
+#include <asm/vtimer.h>
+#include <asm/irq.h>
+#include "entry.h"
+
+static void virt_timer_expire(void);
+
+DEFINE_PER_CPU(struct s390_idle_data, s390_idle);
+
+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 */
+		"	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_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);
+
+void __kprobes vtime_stop_cpu(void)
+{
+	struct s390_idle_data *idle = &__get_cpu_var(s390_idle);
+	unsigned long long idle_time;
+	unsigned long psw_mask;
+
+	trace_hardirqs_on();
+
+	/* 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;
+	idle->nohz_delay = 0;
+
+	/* Call the assembler magic in entry.S */
+	psw_idle(idle, psw_mask);
+
+	/* Account time spent with enabled wait psw loaded as idle time. */
+	idle->sequence++;
+	smp_wmb();
+	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(idle_time);
+	smp_wmb();
+	idle->sequence++;
+}
+
+cputime64_t s390_get_idle_time(int cpu)
+{
+	struct s390_idle_data *idle = &per_cpu(s390_idle, cpu);
+	unsigned long long now, idle_enter, idle_exit;
+	unsigned int sequence;
+
+	do {
+		now = get_tod_clock();
+		sequence = ACCESS_ONCE(idle->sequence);
+		idle_enter = ACCESS_ONCE(idle->clock_idle_enter);
+		idle_exit = ACCESS_ONCE(idle->clock_idle_exit);
+	} while ((sequence & 1) || (ACCESS_ONCE(idle->sequence) != sequence));
+	return idle_enter ? ((idle_exit ?: now) - idle_enter) : 0;
+}
+
+/*
+ * 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 __cpuinit init_cpu_vtimer(void)
+{
+	/* set initial cpu timer */
+	set_vtimer(VTIMER_MAX_SLICE);
+}
+
+static int __cpuinit s390_nohz_notify(struct notifier_block *self,
+				      unsigned long action, void *hcpu)
+{
+	struct s390_idle_data *idle;
+	long cpu = (long) hcpu;
+
+	idle = &per_cpu(s390_idle, cpu);
+	switch (action & ~CPU_TASKS_FROZEN) {
+	case CPU_DYING:
+		idle->nohz_delay = 0;
+	default:
+		break;
+	}
+	return NOTIFY_OK;
+}
+
+void __init vtime_init(void)
+{
+	/* Enable cpu timer interrupts on the boot cpu. */
+	init_cpu_vtimer();
+	cpu_notifier(s390_nohz_notify, 0);
+}