path: root/kernel/timer.c

/*
 *  linux/kernel/timer.c
 *
 *  Kernel internal timers, basic process system calls
 *
 *  Copyright (C) 1991, 1992  Linus Torvalds
 *
 *  1997-01-28  Modified by Finn Arne Gangstad to make timers scale better.
 *
 *  1997-09-10  Updated NTP code according to technical memorandum Jan '96
 *              "A Kernel Model for Precision Timekeeping" by Dave Mills
 *  1998-12-24  Fixed a xtime SMP race (we need the xtime_lock rw spinlock to
 *              serialize accesses to xtime/lost_ticks).
 *                              Copyright (C) 1998  Andrea Arcangeli
 *  1999-03-10  Improved NTP compatibility by Ulrich Windl
 *  2002-05-31	Move sys_sysinfo here and make its locking sane, Robert Love
 *  2000-10-05  Implemented scalable SMP per-CPU timer handling.
 *                              Copyright (C) 2000, 2001, 2002  Ingo Molnar
 *              Designed by David S. Miller, Alexey Kuznetsov and Ingo Molnar
 */

#include <linux/kernel_stat.h>
#include <linux/export.h>
#include <linux/interrupt.h>
#include <linux/percpu.h>
#include <linux/init.h>
#include <linux/mm.h>
#include <linux/swap.h>
#include <linux/pid_namespace.h>
#include <linux/notifier.h>
#include <linux/thread_info.h>
#include <linux/time.h>
#include <linux/jiffies.h>
#include <linux/posix-timers.h>
#include <linux/cpu.h>
#include <linux/syscalls.h>
#include <linux/delay.h>
#include <linux/tick.h>
#include <linux/kallsyms.h>
#include <linux/irq_work.h>
#include <linux/sched.h>
#include <linux/slab.h>

#include <asm/uaccess.h>
#include <asm/unistd.h>
#include <asm/div64.h>
#include <asm/timex.h>
#include <asm/io.h>

#define CREATE_TRACE_POINTS
#include <trace/events/timer.h>

u64 jiffies_64 __cacheline_aligned_in_smp = INITIAL_JIFFIES;

EXPORT_SYMBOL(jiffies_64);

#define TVN_BITS (CONFIG_BASE_SMALL ? 4 : 6)
#define TVR_BITS (CONFIG_BASE_SMALL ? 6 : 8)
#define TVN_SIZE (1 << TVN_BITS)
#define TVR_SIZE (1 << TVR_BITS)
#define TVN_MASK (TVN_SIZE - 1)
#define TVR_MASK (TVR_SIZE - 1)

struct tvec {
	struct list_head vec[TVN_SIZE];
};

struct tvec_root {
	struct list_head vec[TVR_SIZE];
};

struct tvec_base {
	spinlock_t lock;
	struct timer_list *running_timer;
	unsigned long timer_jiffies;
	unsigned long next_timer;
	struct tvec_root tv1;
	struct tvec tv2;
	struct tvec tv3;
	struct tvec tv4;
	struct tvec tv5;
} ____cacheline_aligned;

struct tvec_base boot_tvec_bases;
EXPORT_SYMBOL(boot_tvec_bases);
static DEFINE_PER_CPU(struct tvec_base *, tvec_bases) = &boot_tvec_bases;

static inline unsigned int tbase_get_deferrable(struct tvec_base *base)
{
	return ((unsigned int)(unsigned long)base & TBASE_DEFERRABLE_FLAG);
}

static inline struct tvec_base *tbase_get_base(struct tvec_base *base)
{
	return ((struct tvec_base *)((unsigned long)base & ~TBASE_DEFERRABLE_FLAG));
}

static inline void timer_set_deferrable(struct timer_list *timer)
{
	timer->base = TBASE_MAKE_DEFERRED(timer->base);
}

static inline void
timer_set_base(struct timer_list *timer, struct tvec_base *new_base)
{
	timer->base = (struct tvec_base *)((unsigned long)(new_base) |
				      tbase_get_deferrable(timer->base));
}

static unsigned long round_jiffies_common(unsigned long j, int cpu,
		bool force_up)
{
	int rem;
	unsigned long original = j;

	j += cpu * 3;

	rem = j % HZ;

	if (rem < HZ/4 && !force_up) 
		j = j - rem;
	else 
		j = j - rem + HZ;

	
	j -= cpu * 3;

	if (j <= jiffies) 
		return original;
	return j;
}

unsigned long __round_jiffies(unsigned long j, int cpu)
{
	return round_jiffies_common(j, cpu, false);
}
EXPORT_SYMBOL_GPL(__round_jiffies);

unsigned long __round_jiffies_relative(unsigned long j, int cpu)
{
	unsigned long j0 = jiffies;

	
	return round_jiffies_common(j + j0, cpu, false) - j0;
}
EXPORT_SYMBOL_GPL(__round_jiffies_relative);

unsigned long round_jiffies(unsigned long j)
{
	return round_jiffies_common(j, raw_smp_processor_id(), false);
}
EXPORT_SYMBOL_GPL(round_jiffies);

unsigned long round_jiffies_relative(unsigned long j)
{
	return __round_jiffies_relative(j, raw_smp_processor_id());
}
EXPORT_SYMBOL_GPL(round_jiffies_relative);

unsigned long __round_jiffies_up(unsigned long j, int cpu)
{
	return round_jiffies_common(j, cpu, true);
}
EXPORT_SYMBOL_GPL(__round_jiffies_up);

unsigned long __round_jiffies_up_relative(unsigned long j, int cpu)
{
	unsigned long j0 = jiffies;

	
	return round_jiffies_common(j + j0, cpu, true) - j0;
}
EXPORT_SYMBOL_GPL(__round_jiffies_up_relative);

unsigned long round_jiffies_up(unsigned long j)
{
	return round_jiffies_common(j, raw_smp_processor_id(), true);
}
EXPORT_SYMBOL_GPL(round_jiffies_up);

unsigned long round_jiffies_up_relative(unsigned long j)
{
	return __round_jiffies_up_relative(j, raw_smp_processor_id());
}
EXPORT_SYMBOL_GPL(round_jiffies_up_relative);

void set_timer_slack(struct timer_list *timer, int slack_hz)
{
	timer->slack = slack_hz;
}
EXPORT_SYMBOL_GPL(set_timer_slack);

static void internal_add_timer(struct tvec_base *base, struct timer_list *timer)
{
	unsigned long expires = timer->expires;
	unsigned long idx = expires - base->timer_jiffies;
	struct list_head *vec;

	if (idx < TVR_SIZE) {
		int i = expires & TVR_MASK;
		vec = base->tv1.vec + i;
	} else if (idx < 1 << (TVR_BITS + TVN_BITS)) {
		int i = (expires >> TVR_BITS) & TVN_MASK;
		vec = base->tv2.vec + i;
	} else if (idx < 1 << (TVR_BITS + 2 * TVN_BITS)) {
		int i = (expires >> (TVR_BITS + TVN_BITS)) & TVN_MASK;
		vec = base->tv3.vec + i;
	} else if (idx < 1 << (TVR_BITS + 3 * TVN_BITS)) {
		int i = (expires >> (TVR_BITS + 2 * TVN_BITS)) & TVN_MASK;
		vec = base->tv4.vec + i;
	} else if ((signed long) idx < 0) {
		vec = base->tv1.vec + (base->timer_jiffies & TVR_MASK);
	} else {
		int i;
		if (idx > 0xffffffffUL) {
			idx = 0xffffffffUL;
			expires = idx + base->timer_jiffies;
		}
		i = (expires >> (TVR_BITS + 3 * TVN_BITS)) & TVN_MASK;
		vec = base->tv5.vec + i;
	}
	list_add_tail(&timer->entry, vec);
}

#ifdef CONFIG_TIMER_STATS
void __timer_stats_timer_set_start_info(struct timer_list *timer, void *addr)
{
	if (timer->start_site)
		return;

	timer->start_site = addr;
	memcpy(timer->start_comm, current->comm, TASK_COMM_LEN);
	timer->start_pid = current->pid;
}

static void timer_stats_account_timer(struct timer_list *timer)
{
	unsigned int flag = 0;

	if (likely(!timer->start_site))
		return;
	if (unlikely(tbase_get_deferrable(timer->base)))
		flag |= TIMER_STATS_FLAG_DEFERRABLE;

	timer_stats_update_stats(timer, timer->start_pid, timer->start_site,
				 timer->function, timer->start_comm, flag);
}

#else
static void timer_stats_account_timer(struct timer_list *timer) {}
#endif

#ifdef CONFIG_DEBUG_OBJECTS_TIMERS

static struct debug_obj_descr timer_debug_descr;

static void *timer_debug_hint(void *addr)
{
	return ((struct timer_list *) addr)->function;
}

static int timer_fixup_init(void *addr, enum debug_obj_state state)
{
	struct timer_list *timer = addr;

	switch (state) {
	case ODEBUG_STATE_ACTIVE:
		del_timer_sync(timer);
		debug_object_init(timer, &timer_debug_descr);
		return 1;
	default:
		return 0;
	}
}

static void stub_timer(unsigned long data)
{
	WARN_ON(1);
}

static int timer_fixup_activate(void *addr, enum debug_obj_state state)
{
	struct timer_list *timer = addr;

	switch (state) {

	case ODEBUG_STATE_NOTAVAILABLE:
		if (timer->entry.next == NULL &&
		    timer->entry.prev == TIMER_ENTRY_STATIC) {
			debug_object_init(timer, &timer_debug_descr);
			debug_object_activate(timer, &timer_debug_descr);
			return 0;
		} else {
			setup_timer(timer, stub_timer, 0);
			return 1;
		}
		return 0;

	case ODEBUG_STATE_ACTIVE:
		WARN_ON(1);

	default:
		return 0;
	}
}

static int timer_fixup_free(void *addr, enum debug_obj_state state)
{
	struct timer_list *timer = addr;

	switch (state) {
	case ODEBUG_STATE_ACTIVE:
		del_timer_sync(timer);
		debug_object_free(timer, &timer_debug_descr);
		return 1;
	default:
		return 0;
	}
}

static int timer_fixup_assert_init(void *addr, enum debug_obj_state state)
{
	struct timer_list *timer = addr;

	switch (state) {
	case ODEBUG_STATE_NOTAVAILABLE:
		if (timer->entry.prev == TIMER_ENTRY_STATIC) {
			debug_object_init(timer, &timer_debug_descr);
			return 0;
		} else {
			setup_timer(timer, stub_timer, 0);
			return 1;
		}
	default:
		return 0;
	}
}

static struct debug_obj_descr timer_debug_descr = {
	.name			= "timer_list",
	.debug_hint		= timer_debug_hint,
	.fixup_init		= timer_fixup_init,
	.fixup_activate		= timer_fixup_activate,
	.fixup_free		= timer_fixup_free,
	.fixup_assert_init	= timer_fixup_assert_init,
};

static inline void debug_timer_init(struct timer_list *timer)
{
	debug_object_init(timer, &timer_debug_descr);
}

static inline void debug_timer_activate(struct timer_list *timer)
{
	debug_object_activate(timer, &timer_debug_descr);
}

static inline void debug_timer_deactivate(struct timer_list *timer)
{
	debug_object_deactivate(timer, &timer_debug_descr);
}

static inline void debug_timer_free(struct timer_list *timer)
{
	debug_object_free(timer, &timer_debug_descr);
}

static inline void debug_timer_assert_init(struct timer_list *timer)
{
	debug_object_assert_init(timer, &timer_debug_descr);
}

static void __init_timer(struct timer_list *timer,
			 const char *name,
			 struct lock_class_key *key);

void init_timer_on_stack_key(struct timer_list *timer,
			     const char *name,
			     struct lock_class_key *key)
{
	debug_object_init_on_stack(timer, &timer_debug_descr);
	__init_timer(timer, name, key);
}
EXPORT_SYMBOL_GPL(init_timer_on_stack_key);

void destroy_timer_on_stack(struct timer_list *timer)
{
	debug_object_free(timer, &timer_debug_descr);
}
EXPORT_SYMBOL_GPL(destroy_timer_on_stack);

#else
static inline void debug_timer_init(struct timer_list *timer) { }
static inline void debug_timer_activate(struct timer_list *timer) { }
static inline void debug_timer_deactivate(struct timer_list *timer) { }
static inline void debug_timer_assert_init(struct timer_list *timer) { }
#endif

static inline void debug_init(struct timer_list *timer)
{
	debug_timer_init(timer);
	trace_timer_init(timer);
}

static inline void
debug_activate(struct timer_list *timer, unsigned long expires)
{
	debug_timer_activate(timer);
	trace_timer_start(timer, expires);
}

static inline void debug_deactivate(struct timer_list *timer)
{
	debug_timer_deactivate(timer);
	trace_timer_cancel(timer);
}

static inline void debug_assert_init(struct timer_list *timer)
{
	debug_timer_assert_init(timer);
}

static void __init_timer(struct timer_list *timer,
			 const char *name,
			 struct lock_class_key *key)
{
	timer->entry.next = NULL;
	timer->base = __raw_get_cpu_var(tvec_bases);
	timer->slack = -1;
#ifdef CONFIG_TIMER_STATS
	timer->start_site = NULL;
	timer->start_pid = -1;
	memset(timer->start_comm, 0, TASK_COMM_LEN);
#endif
	lockdep_init_map(&timer->lockdep_map, name, key, 0);
}

void setup_deferrable_timer_on_stack_key(struct timer_list *timer,
					 const char *name,
					 struct lock_class_key *key,
					 void (*function)(unsigned long),
					 unsigned long data)
{
	timer->function = function;
	timer->data = data;
	init_timer_on_stack_key(timer, name, key);
	timer_set_deferrable(timer);
}
EXPORT_SYMBOL_GPL(setup_deferrable_timer_on_stack_key);

void init_timer_key(struct timer_list *timer,
		    const char *name,
		    struct lock_class_key *key)
{
	debug_init(timer);
	__init_timer(timer, name, key);
}
EXPORT_SYMBOL(init_timer_key);

void init_timer_deferrable_key(struct timer_list *timer,
			       const char *name,
			       struct lock_class_key *key)
{
	init_timer_key(timer, name, key);
	timer_set_deferrable(timer);
}
EXPORT_SYMBOL(init_timer_deferrable_key);

static inline void detach_timer(struct timer_list *timer,
				int clear_pending)
{
	struct list_head *entry = &timer->entry;

	debug_deactivate(timer);

	__list_del(entry->prev, entry->next);
	if (clear_pending)
		entry->next = NULL;
	entry->prev = LIST_POISON2;
}

static struct tvec_base *lock_timer_base(struct timer_list *timer,
					unsigned long *flags)
	__acquires(timer->base->lock)
{
	struct tvec_base *base;

	for (;;) {
		struct tvec_base *prelock_base = timer->base;
		base = tbase_get_base(prelock_base);
		if (likely(base != NULL)) {
			spin_lock_irqsave(&base->lock, *flags);
			if (likely(prelock_base == timer->base))
				return base;
			
			spin_unlock_irqrestore(&base->lock, *flags);
		}
		cpu_relax();
	}
}

static inline int
__mod_timer(struct timer_list *timer, unsigned long expires,
						bool pending_only, int pinned)
{
	struct tvec_base *base, *new_base;
	unsigned long flags;
	int ret = 0 , cpu;

	timer_stats_timer_set_start_info(timer);
	BUG_ON(!timer->function);

	base = lock_timer_base(timer, &flags);

	if (timer_pending(timer)) {
		detach_timer(timer, 0);
		if (timer->expires == base->next_timer &&
		    !tbase_get_deferrable(timer->base))
			base->next_timer = base->timer_jiffies;
		ret = 1;
	} else {
		if (pending_only)
			goto out_unlock;
	}

	debug_activate(timer, expires);

	cpu = smp_processor_id();

#if defined(CONFIG_NO_HZ) && defined(CONFIG_SMP)
	if (!pinned && get_sysctl_timer_migration() && idle_cpu(cpu))
		cpu = get_nohz_timer_target();
#endif
	new_base = per_cpu(tvec_bases, cpu);

	if (base != new_base) {
		if (likely(base->running_timer != timer)) {
			
			timer_set_base(timer, NULL);
			dsb();
			spin_unlock(&base->lock);
			base = new_base;
			spin_lock(&base->lock);
			timer_set_base(timer, base);
		}
	}

	timer->expires = expires;
	if (time_before(timer->expires, base->next_timer) &&
	    !tbase_get_deferrable(timer->base))
		base->next_timer = timer->expires;
	internal_add_timer(base, timer);

out_unlock:
	spin_unlock_irqrestore(&base->lock, flags);

	return ret;
}

int mod_timer_pending(struct timer_list *timer, unsigned long expires)
{
	return __mod_timer(timer, expires, true, TIMER_NOT_PINNED);
}
EXPORT_SYMBOL(mod_timer_pending);

static inline
unsigned long apply_slack(struct timer_list *timer, unsigned long expires)
{
	unsigned long expires_limit, mask;
	int bit;

	if (timer->slack >= 0) {
		expires_limit = expires + timer->slack;
	} else {
		long delta = expires - jiffies;

		if (delta < 256)
			return expires;

		expires_limit = expires + delta / 256;
	}
	mask = expires ^ expires_limit;
	if (mask == 0)
		return expires;

	bit = find_last_bit(&mask, BITS_PER_LONG);

	mask = (1UL << bit) - 1;

	expires_limit = expires_limit & ~(mask);

	return expires_limit;
}

int mod_timer(struct timer_list *timer, unsigned long expires)
{
	expires = apply_slack(timer, expires);

	if (timer_pending(timer) && timer->expires == expires)
		return 1;

	return __mod_timer(timer, expires, false, TIMER_NOT_PINNED);
}
EXPORT_SYMBOL(mod_timer);

int mod_timer_pinned(struct timer_list *timer, unsigned long expires)
{
	if (timer->expires == expires && timer_pending(timer))
		return 1;

	return __mod_timer(timer, expires, false, TIMER_PINNED);
}
EXPORT_SYMBOL(mod_timer_pinned);

void add_timer(struct timer_list *timer)
{
	BUG_ON(timer_pending(timer));
	mod_timer(timer, timer->expires);
}
EXPORT_SYMBOL(add_timer);

void add_timer_on(struct timer_list *timer, int cpu)
{
	struct tvec_base *base = per_cpu(tvec_bases, cpu);
	unsigned long flags;

	timer_stats_timer_set_start_info(timer);
	BUG_ON(timer_pending(timer) || !timer->function);
	spin_lock_irqsave(&base->lock, flags);
	timer_set_base(timer, base);
	debug_activate(timer, timer->expires);
	if (time_before(timer->expires, base->next_timer) &&
	    !tbase_get_deferrable(timer->base))
		base->next_timer = timer->expires;
	internal_add_timer(base, timer);
	wake_up_idle_cpu(cpu);
	spin_unlock_irqrestore(&base->lock, flags);
}
EXPORT_SYMBOL_GPL(add_timer_on);

int del_timer(struct timer_list *timer)
{
	struct tvec_base *base;
	unsigned long flags;
	int ret = 0;

	debug_assert_init(timer);

	timer_stats_timer_clear_start_info(timer);
	if (timer_pending(timer)) {
		base = lock_timer_base(timer, &flags);
		if (timer_pending(timer)) {
			detach_timer(timer, 1);
			if (timer->expires == base->next_timer &&
			    !tbase_get_deferrable(timer->base))
				base->next_timer = base->timer_jiffies;
			ret = 1;
		}
		spin_unlock_irqrestore(&base->lock, flags);
	}

	return ret;
}
EXPORT_SYMBOL(del_timer);

int try_to_del_timer_sync(struct timer_list *timer)
{
	struct tvec_base *base;
	unsigned long flags;
	int ret = -1;

	debug_assert_init(timer);

	base = lock_timer_base(timer, &flags);

	if (base->running_timer == timer)
		goto out;

	timer_stats_timer_clear_start_info(timer);
	ret = 0;
	if (timer_pending(timer)) {
		detach_timer(timer, 1);
		if (timer->expires == base->next_timer &&
		    !tbase_get_deferrable(timer->base))
			base->next_timer = base->timer_jiffies;
		ret = 1;
	}
out:
	spin_unlock_irqrestore(&base->lock, flags);

	return ret;
}
EXPORT_SYMBOL(try_to_del_timer_sync);

#ifdef CONFIG_SMP
int del_timer_sync(struct timer_list *timer)
{
#ifdef CONFIG_LOCKDEP
	unsigned long flags;

	local_irq_save(flags);
	lock_map_acquire(&timer->lockdep_map);
	lock_map_release(&timer->lockdep_map);
	local_irq_restore(flags);
#endif
	WARN_ON(in_irq());
	for (;;) {
		int ret = try_to_del_timer_sync(timer);
		if (ret >= 0)
			return ret;
		cpu_relax();
	}
}
EXPORT_SYMBOL(del_timer_sync);
#endif

static int cascade(struct tvec_base *base, struct tvec *tv, int index)
{
	
	struct timer_list *timer, *tmp;
	struct list_head tv_list;

	list_replace_init(tv->vec + index, &tv_list);

	list_for_each_entry_safe(timer, tmp, &tv_list, entry) {
		BUG_ON(tbase_get_base(timer->base) != base);
		internal_add_timer(base, timer);
	}

	return index;
}

static void call_timer_fn(struct timer_list *timer, void (*fn)(unsigned long),
			  unsigned long data)
{
	int preempt_count = preempt_count();

#ifdef CONFIG_LOCKDEP
	struct lockdep_map lockdep_map = timer->lockdep_map;
#endif
	lock_map_acquire(&lockdep_map);

	trace_timer_expire_entry(timer);
	fn(data);
	trace_timer_expire_exit(timer);

	lock_map_release(&lockdep_map);

	if (preempt_count != preempt_count()) {
		WARN_ONCE(1, "timer: %pF preempt leak: %08x -> %08x\n",
			  fn, preempt_count, preempt_count());
		preempt_count() = preempt_count;
	}
}

#define INDEX(N) ((base->timer_jiffies >> (TVR_BITS + (N) * TVN_BITS)) & TVN_MASK)

static inline void __run_timers(struct tvec_base *base)
{
	struct timer_list *timer;

	spin_lock_irq(&base->lock);
	while (time_after_eq(jiffies, base->timer_jiffies)) {
		struct list_head work_list;
		struct list_head *head = &work_list;
		int index = base->timer_jiffies & TVR_MASK;

		if (!index &&
			(!cascade(base, &base->tv2, INDEX(0))) &&
				(!cascade(base, &base->tv3, INDEX(1))) &&
					!cascade(base, &base->tv4, INDEX(2)))
			cascade(base, &base->tv5, INDEX(3));
		++base->timer_jiffies;
		list_replace_init(base->tv1.vec + index, &work_list);
		while (!list_empty(head)) {
			void (*fn)(unsigned long);
			unsigned long data;

			timer = list_first_entry(head, struct timer_list,entry);
			fn = timer->function;
			data = timer->data;

			timer_stats_account_timer(timer);

			base->running_timer = timer;
			detach_timer(timer, 1);

			spin_unlock_irq(&base->lock);
			call_timer_fn(timer, fn, data);
			spin_lock_irq(&base->lock);
		}
	}
	base->running_timer = NULL;
	spin_unlock_irq(&base->lock);
}

#ifdef CONFIG_NO_HZ
static unsigned long __next_timer_interrupt(struct tvec_base *base)
{
	unsigned long timer_jiffies = base->timer_jiffies;
	unsigned long expires = timer_jiffies + NEXT_TIMER_MAX_DELTA;
	int index, slot, array, found = 0;
	struct timer_list *nte;
	struct tvec *varray[4];

	
	index = slot = timer_jiffies & TVR_MASK;
	do {
		list_for_each_entry(nte, base->tv1.vec + slot, entry) {
			if (tbase_get_deferrable(nte->base))
				continue;

			found = 1;
			expires = nte->expires;
			
			if (!index || slot < index)
				goto cascade;
			return expires;
		}
		slot = (slot + 1) & TVR_MASK;
	} while (slot != index);

cascade:
	
	if (index)
		timer_jiffies += TVR_SIZE - index;
	timer_jiffies >>= TVR_BITS;

	
	varray[0] = &base->tv2;
	varray[1] = &base->tv3;
	varray[2] = &base->tv4;
	varray[3] = &base->tv5;

	for (array = 0; array < 4; array++) {
		struct tvec *varp = varray[array];

		index = slot = timer_jiffies & TVN_MASK;
		do {
			list_for_each_entry(nte, varp->vec + slot, entry) {
				if (tbase_get_deferrable(nte->base))
					continue;

				found = 1;
				if (time_before(nte->expires, expires))
					expires = nte->expires;
			}
			if (found) {
				
				if (!index || slot < index)
					break;
				return expires;
			}
			slot = (slot + 1) & TVN_MASK;
		} while (slot != index);

		if (index)
			timer_jiffies += TVN_SIZE - index;
		timer_jiffies >>= TVN_BITS;
	}
	return expires;
}

static unsigned long cmp_next_hrtimer_event(unsigned long now,
					    unsigned long expires)
{
	ktime_t hr_delta = hrtimer_get_next_event();
	struct timespec tsdelta;
	unsigned long delta;

	if (hr_delta.tv64 == KTIME_MAX)
		return expires;

	if (hr_delta.tv64 <= 0)
		return now + 1;

	tsdelta = ktime_to_timespec(hr_delta);
	delta = timespec_to_jiffies(&tsdelta);

	if (delta > NEXT_TIMER_MAX_DELTA)
		delta = NEXT_TIMER_MAX_DELTA;

	if (delta < 1)
		delta = 1;
	now += delta;
	if (time_before(now, expires))
		return now;
	return expires;
}

unsigned long get_next_timer_interrupt(unsigned long now)
{
	struct tvec_base *base = __this_cpu_read(tvec_bases);
	unsigned long expires;

	if (cpu_is_offline(smp_processor_id()))
		return now + NEXT_TIMER_MAX_DELTA;
	spin_lock(&base->lock);
	if (time_before_eq(base->next_timer, base->timer_jiffies))
		base->next_timer = __next_timer_interrupt(base);
	expires = base->next_timer;
	spin_unlock(&base->lock);

	if (time_before_eq(expires, now))
		return now;

	return cmp_next_hrtimer_event(now, expires);
}
#endif

void update_process_times(int user_tick)
{
	struct task_struct *p = current;
	int cpu = smp_processor_id();

	
	account_process_tick(p, user_tick);
	run_local_timers();
	rcu_check_callbacks(cpu, user_tick);
#ifdef CONFIG_IRQ_WORK
	if (in_irq())
		irq_work_run();
#endif
	scheduler_tick();
	run_posix_cpu_timers(p);
}

static void run_timer_softirq(struct softirq_action *h)
{
	struct tvec_base *base = __this_cpu_read(tvec_bases);

	hrtimer_run_pending();

	if (time_after_eq(jiffies, base->timer_jiffies))
		__run_timers(base);
}

void run_local_timers(void)
{
	hrtimer_run_queues();
	raise_softirq(TIMER_SOFTIRQ);
}

#ifdef __ARCH_WANT_SYS_ALARM

SYSCALL_DEFINE1(alarm, unsigned int, seconds)
{
	return alarm_setitimer(seconds);
}

#endif

#ifndef __alpha__


SYSCALL_DEFINE0(getpid)
{
	return task_tgid_vnr(current);
}

SYSCALL_DEFINE0(getppid)
{
	int pid;

	rcu_read_lock();
	pid = task_tgid_vnr(rcu_dereference(current->real_parent));
	rcu_read_unlock();

	return pid;
}

SYSCALL_DEFINE0(getuid)
{
	
	return current_uid();
}

SYSCALL_DEFINE0(geteuid)
{
	
	return current_euid();
}

SYSCALL_DEFINE0(getgid)
{
	
	return current_gid();
}

SYSCALL_DEFINE0(getegid)
{
	
	return  current_egid();
}

#endif

static void process_timeout(unsigned long __data)
{
	wake_up_process((struct task_struct *)__data);
}

signed long __sched schedule_timeout(signed long timeout)
{
	struct timer_list timer;
	unsigned long expire;

	switch (timeout)
	{
	case MAX_SCHEDULE_TIMEOUT:
		schedule();
		goto out;
	default:
		if (timeout < 0) {
			printk(KERN_ERR "schedule_timeout: wrong timeout "
				"value %lx\n", timeout);
			dump_stack();
			current->state = TASK_RUNNING;
			goto out;
		}
	}

	expire = timeout + jiffies;

	setup_timer_on_stack(&timer, process_timeout, (unsigned long)current);
	__mod_timer(&timer, expire, false, TIMER_NOT_PINNED);
	schedule();
	del_singleshot_timer_sync(&timer);

	
	destroy_timer_on_stack(&timer);

	timeout = expire - jiffies;

 out:
	return timeout < 0 ? 0 : timeout;
}
EXPORT_SYMBOL(schedule_timeout);

signed long __sched schedule_timeout_interruptible(signed long timeout)
{
	__set_current_state(TASK_INTERRUPTIBLE);
	return schedule_timeout(timeout);
}
EXPORT_SYMBOL(schedule_timeout_interruptible);

signed long __sched schedule_timeout_killable(signed long timeout)
{
	__set_current_state(TASK_KILLABLE);
	return schedule_timeout(timeout);
}
EXPORT_SYMBOL(schedule_timeout_killable);

signed long __sched schedule_timeout_uninterruptible(signed long timeout)
{
	__set_current_state(TASK_UNINTERRUPTIBLE);
	return schedule_timeout(timeout);
}
EXPORT_SYMBOL(schedule_timeout_uninterruptible);

SYSCALL_DEFINE0(gettid)
{
	return task_pid_vnr(current);
}

int do_sysinfo(struct sysinfo *info)
{
	unsigned long mem_total, sav_total;
	unsigned int mem_unit, bitcount;
	struct timespec tp;

	memset(info, 0, sizeof(struct sysinfo));

	ktime_get_ts(&tp);
	monotonic_to_bootbased(&tp);
	info->uptime = tp.tv_sec + (tp.tv_nsec ? 1 : 0);

	get_avenrun(info->loads, 0, SI_LOAD_SHIFT - FSHIFT);

	info->procs = nr_threads;

	si_meminfo(info);
	si_swapinfo(info);


	mem_total = info->totalram + info->totalswap;
	if (mem_total < info->totalram || mem_total < info->totalswap)
		goto out;
	bitcount = 0;
	mem_unit = info->mem_unit;
	while (mem_unit > 1) {
		bitcount++;
		mem_unit >>= 1;
		sav_total = mem_total;
		mem_total <<= 1;
		if (mem_total < sav_total)
			goto out;
	}


	info->mem_unit = 1;
	info->totalram <<= bitcount;
	info->freeram <<= bitcount;
	info->sharedram <<= bitcount;
	info->bufferram <<= bitcount;
	info->totalswap <<= bitcount;
	info->freeswap <<= bitcount;
	info->totalhigh <<= bitcount;
	info->freehigh <<= bitcount;

out:
	return 0;
}

SYSCALL_DEFINE1(sysinfo, struct sysinfo __user *, info)
{
	struct sysinfo val;

	do_sysinfo(&val);

	if (copy_to_user(info, &val, sizeof(struct sysinfo)))
		return -EFAULT;

	return 0;
}

static int __cpuinit init_timers_cpu(int cpu)
{
	int j;
	struct tvec_base *base;
	static char __cpuinitdata tvec_base_done[NR_CPUS];
	unsigned long flags;

	if (!tvec_base_done[cpu]) {
		static char boot_done;

		if (boot_done) {
			base = kmalloc_node(sizeof(*base),
						GFP_KERNEL | __GFP_ZERO,
						cpu_to_node(cpu));
			if (!base)
				return -ENOMEM;

			
			if (tbase_get_deferrable(base)) {
				WARN_ON(1);
				kfree(base);
				return -ENOMEM;
			}
			per_cpu(tvec_bases, cpu) = base;
		} else {
			boot_done = 1;
			base = &boot_tvec_bases;
		}
		spin_lock_init(&base->lock);
		tvec_base_done[cpu] = 1;
	} else {
		base = per_cpu(tvec_bases, cpu);
	}

	spin_lock_irqsave(&base->lock, flags);

	for (j = 0; j < TVN_SIZE; j++) {
		INIT_LIST_HEAD(base->tv5.vec + j);
		INIT_LIST_HEAD(base->tv4.vec + j);
		INIT_LIST_HEAD(base->tv3.vec + j);
		INIT_LIST_HEAD(base->tv2.vec + j);
	}
	for (j = 0; j < TVR_SIZE; j++)
		INIT_LIST_HEAD(base->tv1.vec + j);

	base->timer_jiffies = jiffies;
	base->next_timer = base->timer_jiffies;

	spin_unlock_irqrestore(&base->lock, flags);

	return 0;
}

#ifdef CONFIG_HOTPLUG_CPU
static void migrate_timer_list(struct tvec_base *new_base, struct list_head *head)
{
	struct timer_list *timer;

	while (!list_empty(head)) {
		timer = list_first_entry(head, struct timer_list, entry);
		detach_timer(timer, 0);
		timer_set_base(timer, new_base);
		if (time_before(timer->expires, new_base->next_timer) &&
		    !tbase_get_deferrable(timer->base))
			new_base->next_timer = timer->expires;
		internal_add_timer(new_base, timer);
	}
}

static void __cpuinit migrate_timers(int cpu)
{
	struct tvec_base *old_base;
	struct tvec_base *new_base;
	int i;

	BUG_ON(cpu_online(cpu));
	old_base = per_cpu(tvec_bases, cpu);
	new_base = get_cpu_var(tvec_bases);
	spin_lock_irq(&new_base->lock);
	spin_lock_nested(&old_base->lock, SINGLE_DEPTH_NESTING);

	BUG_ON(old_base->running_timer);

	for (i = 0; i < TVR_SIZE; i++)
		migrate_timer_list(new_base, old_base->tv1.vec + i);
	for (i = 0; i < TVN_SIZE; i++) {
		migrate_timer_list(new_base, old_base->tv2.vec + i);
		migrate_timer_list(new_base, old_base->tv3.vec + i);
		migrate_timer_list(new_base, old_base->tv4.vec + i);
		migrate_timer_list(new_base, old_base->tv5.vec + i);
	}

	spin_unlock(&old_base->lock);
	spin_unlock_irq(&new_base->lock);
	put_cpu_var(tvec_bases);
}
#endif 

static int __cpuinit timer_cpu_notify(struct notifier_block *self,
				unsigned long action, void *hcpu)
{
	long cpu = (long)hcpu;
	int err;

	switch(action) {
	case CPU_UP_PREPARE:
	case CPU_UP_PREPARE_FROZEN:
		err = init_timers_cpu(cpu);
		if (err < 0)
			return notifier_from_errno(err);
		break;
#ifdef CONFIG_HOTPLUG_CPU
	case CPU_DEAD:
	case CPU_DEAD_FROZEN:
		migrate_timers(cpu);
		break;
#endif
	default:
		break;
	}
	return NOTIFY_OK;
}

static struct notifier_block __cpuinitdata timers_nb = {
	.notifier_call	= timer_cpu_notify,
};


void __init init_timers(void)
{
	int err = timer_cpu_notify(&timers_nb, (unsigned long)CPU_UP_PREPARE,
				(void *)(long)smp_processor_id());

	init_timer_stats();

	BUG_ON(err != NOTIFY_OK);
	register_cpu_notifier(&timers_nb);
	open_softirq(TIMER_SOFTIRQ, run_timer_softirq);
}

void msleep(unsigned int msecs)
{
	unsigned long timeout = msecs_to_jiffies(msecs) + 1;

	while (timeout)
		timeout = schedule_timeout_uninterruptible(timeout);
}

EXPORT_SYMBOL(msleep);

unsigned long msleep_interruptible(unsigned int msecs)
{
	unsigned long timeout = msecs_to_jiffies(msecs) + 1;

	while (timeout && !signal_pending(current))
		timeout = schedule_timeout_interruptible(timeout);
	return jiffies_to_msecs(timeout);
}

EXPORT_SYMBOL(msleep_interruptible);

static void do_nsleep(unsigned int msecs, struct hrtimer_sleeper *sleeper,
	int sigs)
{
	enum hrtimer_mode mode = HRTIMER_MODE_REL;
	int state = sigs ? TASK_INTERRUPTIBLE : TASK_UNINTERRUPTIBLE;

	hrtimer_init(&sleeper->timer, CLOCK_MONOTONIC, mode);
	sleeper->timer.node.expires = ktime_set(msecs / 1000,
						(msecs % 1000) * NSEC_PER_MSEC);
	hrtimer_init_sleeper(sleeper, current);

	do {
		set_current_state(state);
		hrtimer_start(&sleeper->timer, sleeper->timer.node.expires, mode);
		if (sleeper->task)
			schedule();
		hrtimer_cancel(&sleeper->timer);
		mode = HRTIMER_MODE_ABS;
	} while (sleeper->task && !(sigs && signal_pending(current)));
}

void hr_msleep(unsigned int msecs)
{
	struct hrtimer_sleeper sleeper;

	do_nsleep(msecs, &sleeper, 0);
}

EXPORT_SYMBOL(hr_msleep);

unsigned long hr_msleep_interruptible(unsigned int msecs)
{
	struct hrtimer_sleeper sleeper;
	ktime_t left;

	do_nsleep(msecs, &sleeper, 1);

	if (!sleeper.task)
		return 0;
	left = ktime_sub(sleeper.timer.node.expires,
				sleeper.timer.base->get_time());
	return max(((long) ktime_to_ns(left))/(long)NSEC_PER_MSEC, 1L);
}

EXPORT_SYMBOL(hr_msleep_interruptible);

static int __sched do_usleep_range(unsigned long min, unsigned long max)
{
	ktime_t kmin;
	unsigned long delta;

	kmin = ktime_set(0, min * NSEC_PER_USEC);
	delta = (max - min) * NSEC_PER_USEC;
	return schedule_hrtimeout_range(&kmin, delta, HRTIMER_MODE_REL);
}

void usleep_range(unsigned long min, unsigned long max)
{
	__set_current_state(TASK_UNINTERRUPTIBLE);
	do_usleep_range(min, max);
}
EXPORT_SYMBOL(usleep_range);