[PATCH] s390: virtual timer interface.

From: Martin Schwidefsky <schwidefsky@de.ibm.com>

Add virtual timer interface.

arch/s390/Kconfig

@@ -250,6 +250,12 @@ config SHARED_KERNEL
 	  You should only select this option if you know what you are
 	  doing and want to exploit this feature.
 
+config VIRT_TIMER
+	bool "Virtual CPU timer support"
+	help
+	  This provides a kernel interface for virtual CPU timers.
+	  Default is disabled.
+
 endmenu
 
 config PCMCIA

arch/s390/defconfig

@@ -76,6 +76,7 @@ CONFIG_BINFMT_MISC=m
 # CONFIG_PROCESS_DEBUG is not set
 CONFIG_PFAULT=y
 # CONFIG_SHARED_KERNEL is not set
+# CONFIG_VIRT_TIMER is not set
 # CONFIG_PCMCIA is not set
 
 #

arch/s390/kernel/process.c

@@ -40,6 +40,9 @@
 #include <asm/io.h>
 #include <asm/processor.h>
 #include <asm/irq.h>
+#ifdef CONFIG_VIRT_TIMER
+#include <asm/timer.h>
+#endif
 
 asmlinkage void ret_from_fork(void) __asm__("ret_from_fork");
 
@@ -77,6 +80,14 @@ void default_idle(void)
                 return;
         }
 
+#ifdef CONFIG_VIRT_TIMER
+	/*
+	 * hook to stop timers that should not tick while CPU is idle
+	 */
+	if (stop_timers())
+		return;
+#endif
+
 	/* 
 	 * Wait for external, I/O or machine check interrupt and
 	 * switch off machine check bit after the wait has ended.

arch/s390/kernel/s390_ext.c

@@ -111,6 +111,7 @@ void do_extint(struct pt_regs *regs, unsigned short code)
         int index;
 
 	irq_enter();
+	asm volatile ("mc 0,0");
 	if (S390_lowcore.int_clock >= S390_lowcore.jiffy_timer)
 		account_ticks(regs);
 	kstat_cpu(smp_processor_id()).irqs[EXTERNAL_INTERRUPT]++;

arch/s390/kernel/s390_ksyms.c

@@ -19,6 +19,9 @@
 #ifdef CONFIG_IP_MULTICAST
 #include <net/arp.h>
 #endif
+#ifdef CONFIG_VIRT_TIMER
+#include <asm/timer.h>
+#endif
 
 /*
  * memory management
@@ -65,6 +68,17 @@ EXPORT_SYMBOL(overflowuid);
 EXPORT_SYMBOL(overflowgid);
 EXPORT_SYMBOL(empty_zero_page);
 
+/*
+ * virtual CPU timer
+ */
+#ifdef CONFIG_VIRT_TIMER
+EXPORT_SYMBOL(init_virt_timer);
+EXPORT_SYMBOL(add_virt_timer);
+EXPORT_SYMBOL(add_virt_timer_periodic);
+EXPORT_SYMBOL(mod_virt_timer);
+EXPORT_SYMBOL(del_virt_timer);
+#endif
+
 /*
  * misc.
  */
@@ -77,5 +91,5 @@ EXPORT_SYMBOL(console_device);
 EXPORT_SYMBOL_NOVERS(do_call_softirq);
 EXPORT_SYMBOL(sys_wait4);
 EXPORT_SYMBOL(cpcmd);
+EXPORT_SYMBOL(smp_call_function_on);
 EXPORT_SYMBOL(sys_ioctl);
-

arch/s390/kernel/smp.c

@@ -30,6 +30,7 @@
 
 #include <linux/delay.h>
 #include <linux/cache.h>
+#include <linux/interrupt.h>
 
 #include <asm/sigp.h>
 #include <asm/pgalloc.h>
@@ -65,7 +66,7 @@ extern char vmpoff_cmd[];
 
 extern void do_reipl(unsigned long devno);
 
-static sigp_ccode smp_ext_bitcall(int, ec_bit_sig);
+static void smp_ext_bitcall(int, ec_bit_sig);
 static void smp_ext_bitcall_others(ec_bit_sig);
 
 /*
@@ -150,6 +151,59 @@ int smp_call_function (void (*func) (void *info), void *info, int nonatomic,
 	return 0;
 }
 
+/*
+ * Call a function on one CPU
+ * cpu : the CPU the function should be executed on
+ *
+ * You must not call this function with disabled interrupts or from a
+ * hardware interrupt handler. You may call it from a bottom half.
+ *
+ * It is guaranteed that the called function runs on the specified CPU,
+ * preemption is disabled.
+ */
+int smp_call_function_on(void (*func) (void *info), void *info,
+			 int nonatomic, int wait, int cpu)
+{
+	struct call_data_struct data;
+	int curr_cpu;
+
+	if (!cpu_online(cpu))
+		return -EINVAL;
+
+	/* disable preemption for local function call */
+	curr_cpu = get_cpu();
+
+	if (curr_cpu == cpu) {
+		/* direct call to function */
+		func(info);
+		put_cpu();
+		return 0;
+	}
+
+	data.func = func;
+	data.info = info;
+	atomic_set(&data.started, 0);
+	data.wait = wait;
+	if (wait)
+		atomic_set(&data.finished, 0);
+
+	spin_lock_bh(&call_lock);
+	call_data = &data;
+	smp_ext_bitcall(cpu, ec_call_function);
+
+	/* Wait for response */
+	while (atomic_read(&data.started) != 1)
+		cpu_relax();
+
+	if (wait)
+		while (atomic_read(&data.finished) != 1)
+			cpu_relax();
+
+	spin_unlock_bh(&call_lock);
+	put_cpu();
+	return 0;
+}
+
 static inline void do_send_stop(void)
 {
         u32 dummy;
@@ -305,16 +359,14 @@ void do_ext_call_interrupt(struct pt_regs *regs, __u16 code)
  * Send an external call sigp to another cpu and return without waiting
  * for its completion.
  */
-static sigp_ccode smp_ext_bitcall(int cpu, ec_bit_sig sig)
+static void smp_ext_bitcall(int cpu, ec_bit_sig sig)
 {
-        sigp_ccode ccode;
-
         /*
          * Set signaling bit in lowcore of target cpu and kick it
          */
 	set_bit(sig, (unsigned long *) &lowcore_ptr[cpu]->ext_call_fast);
-        ccode = signal_processor(cpu, sigp_external_call);
-        return ccode;
+	while(signal_processor(cpu, sigp_external_call) == sigp_busy)
+		udelay(10);
 }
 
 /*

arch/s390/kernel/time.c

@@ -24,16 +24,17 @@
 #include <linux/init.h>
 #include <linux/smp.h>
 #include <linux/types.h>
+#include <linux/timex.h>
+#include <linux/config.h>
 
 #include <asm/uaccess.h>
 #include <asm/delay.h>
 #include <asm/s390_ext.h>
 #include <asm/div64.h>
-
-#include <linux/timex.h>
-#include <linux/config.h>
-
 #include <asm/irq.h>
+#ifdef CONFIG_VIRT_TIMER
+#include <asm/timer.h>
+#endif
 
 /* change this if you have some constant time drift */
 #define USECS_PER_JIFFY     ((unsigned long) 1000000/HZ)
@@ -51,13 +52,19 @@ u64 jiffies_64 = INITIAL_JIFFIES;
 
 EXPORT_SYMBOL(jiffies_64);
 
-static ext_int_info_t ext_int_info_timer;
+static ext_int_info_t ext_int_info_cc;
 static u64 init_timer_cc;
 static u64 jiffies_timer_cc;
 static u64 xtime_cc;
 
 extern unsigned long wall_jiffies;
 
+#ifdef CONFIG_VIRT_TIMER
+#define VTIMER_MAGIC (0x4b87ad6e + 1)
+static ext_int_info_t ext_int_info_timer;
+DEFINE_PER_CPU(struct vtimer_queue, virt_cpu_timer);
+#endif
+
 /*
  * Scheduler clock - returns current time in nanosec units.
  */
@@ -226,13 +233,208 @@ void account_ticks(struct pt_regs *regs)
 #endif
 }
 
+#ifdef CONFIG_VIRT_TIMER
+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);
+}
+
+int 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 1;
+	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);
+	return 0;
+}
+
+void do_monitor_call(struct pt_regs *regs, long interruption_code)
+{
+	/* disable monitor call class 0 */
+	__ctl_clear_bit(8, 15);
+
+	start_cpu_timer();
+}
+
 /*
- * Start the clock comparator on the current CPU.
+ * called from cpu_idle to stop any timers
+ * returns 1 if CPU should not be stopped
+ */
+int stop_timers(void)
+{
+	if (stop_cpu_timer())
+		return 1;
+
+	/* enable monitor call class 0 */
+	__ctl_set_bit(8, 15);
+
+	return 0;
+}
+
+void set_vtimer(__u64 expires)
+{
+	asm volatile ("SPT %0" : : "m" (expires));
+
+	/* store expire time for this CPU timer */
+	per_cpu(virt_cpu_timer, smp_processor_id()).to_expire = expires;
+}
+
+/*
+ * Sorted add to a list. List is linear searched until first bigger
+ * element is found.
+ */
+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);
+}
+#endif
+
+/*
+ * Start the clock comparator and the virtual CPU timer
+ * on the current CPU.
  */
 void init_cpu_timer(void)
 {
 	unsigned long cr0;
 	__u64 timer;
+#ifdef CONFIG_VIRT_TIMER
+	struct vtimer_queue *vt_list;
+#endif
 
 	timer = jiffies_timer_cc + jiffies_64 * CLK_TICKS_PER_JIFFY;
 	S390_lowcore.jiffy_timer = timer + CLK_TICKS_PER_JIFFY;
@@ -242,6 +444,22 @@ void init_cpu_timer(void)
 	__ctl_store(cr0, 0, 0);
         cr0 |= 0x800;
 	__ctl_load(cr0, 0, 0);
+
+#ifdef CONFIG_VIRT_TIMER
+	/* kick the virtual timer */
+	timer = VTIMER_MAX_SLICE;
+	asm volatile ("SPT %0" : : "m" (timer));
+	__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;
+#endif
 }
 
 /*
@@ -281,11 +499,252 @@ void __init time_init(void)
         set_normalized_timespec(&wall_to_monotonic,
                                 -xtime.tv_sec, -xtime.tv_nsec);
 
-        /* request the 0x1004 external interrupt */
+	/* request the clock comparator external interrupt */
         if (register_early_external_interrupt(0x1004, 0,
-					      &ext_int_info_timer) != 0)
+					      &ext_int_info_cc) != 0)
                 panic("Couldn't request external interrupt 0x1004");
 
-        /* init CPU timer */
+#ifdef CONFIG_VIRT_TIMER
+	/* 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");
+#endif
+
         init_cpu_timer();
 }
+
+#ifdef CONFIG_VIRT_TIMER
+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);
+}
+
+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);
+}
+
+/*
+ * 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);
+}
+
+/*
+ * 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;
+}
+
+/*
+ * 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;
+
+	if (!cpu_online(timer->cpu)) {
+		printk("del_virt_timer: CPU not present!\n");
+		return -1;
+	}
+
+	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;
+}
+#endif
+

arch/s390/kernel/traps.c

@@ -64,6 +64,9 @@ extern void pfault_fini(void);
 extern void pfault_interrupt(struct pt_regs *regs, __u16 error_code);
 static ext_int_info_t ext_int_pfault;
 #endif
+#ifdef CONFIG_VIRT_TIMER
+extern pgm_check_handler_t do_monitor_call;
+#endif
 
 #define stack_pointer ({ void **sp; asm("la %0,0(15)" : "=&d" (sp)); sp; })
 
@@ -625,6 +628,9 @@ void __init trap_init(void)
 #endif /* CONFIG_ARCH_S390X */
         pgm_check_table[0x15] = &operand_exception;
         pgm_check_table[0x1C] = &privileged_op;
+#ifdef CONFIG_VIRT_TIMER
+	pgm_check_table[0x40] = &do_monitor_call;
+#endif
 	if (MACHINE_IS_VM) {
 		/*
 		 * First try to get pfault pseudo page faults going.

drivers/s390/cio/cio.c

@@ -607,6 +607,7 @@ do_IRQ (struct pt_regs *regs)
 	struct irb *irb;
 
 	irq_enter ();
+	asm volatile ("mc 0,0");
 	if (S390_lowcore.int_clock >= S390_lowcore.jiffy_timer)
 		account_ticks(regs);
 	/*

include/asm-s390/smp.h

@@ -29,6 +29,9 @@ typedef struct
 	__u16      cpu;
 } sigp_info;
 
+extern int smp_call_function_on(void (*func) (void *info), void *info,
+				int nonatomic, int wait, int cpu);
+
 extern cpumask_t cpu_online_map;
 extern cpumask_t cpu_possible_map;
 
@@ -61,4 +64,9 @@ extern __inline__ __u16 hard_smp_processor_id(void)
 #define cpu_logical_map(cpu) (cpu)
 
 #endif
+
+#ifndef CONFIG_SMP
+#define smp_call_function_on(func,info,nonatomic,wait,cpu)      ({ 0; })
+#endif
+
 #endif

include/asm-s390/timer.h

+/*
+ *  include/asm-s390/timer.h
+ *
+ *  (C) Copyright IBM Corp. 2003
+ *  Virtual CPU timer
+ *
+ *  Author: Jan Glauber (jang@de.ibm.com)
+ */
+
+#ifndef _ASM_S390_TIMER_H
+#define _ASM_S390_TIMER_H
+
+#include <linux/timer.h>
+
+#define VTIMER_MAX_SLICE (0x7ffffffffffff000LL)
+
+struct vtimer_list {
+	struct list_head entry;
+
+	int cpu;
+	__u64 expires;
+	__u64 interval;
+
+	spinlock_t lock;
+	unsigned long magic;
+
+	void (*function)(unsigned long, struct pt_regs*);
+	unsigned long data;
+};
+
+/* the offset value will wrap after ca. 71 years */
+struct vtimer_queue {
+	struct list_head list;
+	spinlock_t lock;
+	__u64 to_expire;	  /* current event expire time */
+	__u64 offset;		  /* list offset to zero */
+	__u64 idle;		  /* temp var for idle */
+};
+
+void set_vtimer(__u64 expires);
+
+extern void init_virt_timer(struct vtimer_list *timer);
+extern void add_virt_timer(void *new);
+extern void add_virt_timer_periodic(void *new);
+extern int mod_virt_timer(struct vtimer_list *timer, __u64 expires);
+extern int del_virt_timer(struct vtimer_list *timer);
+
+int stop_timers(void);
+
+#endif