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/*
 *  linux/kernel/sched.c
 *
 *  Copyright (C) 1991, 1992  Linus Torvalds
 *
 *  1996-04-21	Modified by Ulrich Windl to make NTP work
 *  1996-12-23  Modified by Dave Grothe to fix bugs in semaphores and
 *              make semaphores SMP safe
 *  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
 */
 
/*
 * 'sched.c' is the main kernel file. It contains scheduling primitives
 * (sleep_on, wakeup, schedule etc) as well as a number of simple system
 * call functions (type getpid()), which just extract a field from
 * current-task
 */
 
/*
 * uClinux revisions for NO_MM
 * Copyright (C) 1998  Kenneth Albanowski <kjahds@kjahds.com>,
 *                     The Silver Hammer Group, Ltd.
 */  
 
#include <linux/signal.h>
#include <linux/sched.h>
#include <linux/timer.h>
#include <linux/kernel.h>
#include <linux/kernel_stat.h>
#include <linux/fdreg.h>
#include <linux/errno.h>
#include <linux/time.h>
#include <linux/ptrace.h>
#include <linux/delay.h>
#include <linux/interrupt.h>
#include <linux/tqueue.h>
#include <linux/resource.h>
#include <linux/mm.h>
#include <linux/smp.h>
 
#include <asm/system.h>
#include <asm/io.h>
#include <asm/segment.h>
#include <asm/pgtable.h>
#include <asm/mmu_context.h>
 
#include <linux/timex.h>
 
/* SIMON - I don't know why the fuck this prototype can't be in header but it won't work */
extern void switch_to(struct task_struct *prev, struct task_struct *next);
 
 
/*
 * kernel variables
 */
 
int securelevel = 0;			/* system security level */
 
long tick = (1000000 + HZ/2) / HZ;	/* timer interrupt period */
volatile struct timeval xtime;		/* The current time */
int tickadj = 500/HZ ? 500/HZ : 1;	/* microsecs */
 
DECLARE_TASK_QUEUE(tq_timer);
DECLARE_TASK_QUEUE(tq_immediate);
DECLARE_TASK_QUEUE(tq_scheduler);
 
/*
 * phase-lock loop variables
 */
/* TIME_ERROR prevents overwriting the CMOS clock */
int time_state = TIME_ERROR;	/* clock synchronization status */
int time_status = STA_UNSYNC;	/* clock status bits */
long time_offset = 0;		/* time adjustment (us) */
long time_constant = 2;		/* pll time constant */
long time_tolerance = MAXFREQ;	/* frequency tolerance (ppm) */
long time_precision = 1;	/* clock precision (us) */
long time_maxerror = NTP_PHASE_LIMIT;	/* maximum error (us) */
long time_esterror = NTP_PHASE_LIMIT;	/* estimated error (us) */
long time_phase = 0;		/* phase offset (scaled us) */
long time_freq = ((1000000 + HZ/2) % HZ - HZ/2) << SHIFT_USEC;	/* frequency offset (scaled ppm) */
long time_adj = 0;		/* tick adjust (scaled 1 / HZ) */
long time_reftime = 0;		/* time at last adjustment (s) */
 
long time_adjust = 0;
long time_adjust_step = 0;
 
int need_resched = 0;
unsigned long event = 0;
 
extern int _setitimer(int, struct itimerval *, struct itimerval *);
unsigned int * prof_buffer = NULL;
unsigned long prof_len = 0;
unsigned long prof_shift = 0;
 
#define _S(nr) (1<<((nr)-1))
 
extern void mem_use(void);
 
unsigned long init_kernel_stack[1024] = { STACK_MAGIC, };
#ifndef NO_MM
unsigned long init_user_stack[1024] = { STACK_MAGIC, };
static struct vm_area_struct init_mmap = INIT_MMAP;
#endif /* !NO_MM */
static struct fs_struct init_fs = INIT_FS;
static struct files_struct init_files = INIT_FILES;
static struct signal_struct init_signals = INIT_SIGNALS;
 
struct mm_struct init_mm = INIT_MM;
struct task_struct init_task = INIT_TASK;
 
unsigned long volatile jiffies=0;
 
struct task_struct *current_set[NR_CPUS];
struct task_struct *last_task_used_math = NULL;
 
struct task_struct * task[NR_TASKS] = {&init_task, };
 
struct kernel_stat kstat = { 0 };
 
static inline void add_to_runqueue(struct task_struct * p)
{
#ifdef __SMP__
	int cpu=smp_processor_id();
#endif	
#if 1	/* sanity tests */
	if (p->next_run || p->prev_run) {
		printk("task already on run-queue\n");
		return;
	}
#endif
	if (p->policy != SCHED_OTHER || p->counter > current->counter + 3)
		need_resched = 1;
	nr_running++;
	(p->prev_run = init_task.prev_run)->next_run = p;
	p->next_run = &init_task;
	init_task.prev_run = p;
#ifdef __SMP__
	/* this is safe only if called with cli()*/
	while(set_bit(31,&smp_process_available))
	{
		while(test_bit(31,&smp_process_available))
		{
			if(clear_bit(cpu,&smp_invalidate_needed))
			{
				local_flush_tlb();
				set_bit(cpu,&cpu_callin_map[0]);
			}
		}
	}
	smp_process_available++;
	clear_bit(31,&smp_process_available);
	if ((0!=p->pid) && smp_threads_ready)
	{
		int i;
		for (i=0;i<smp_num_cpus;i++)
		{
			if (0==current_set[cpu_logical_map[i]]->pid) 
			{
				smp_message_pass(cpu_logical_map[i], MSG_RESCHEDULE, 0L, 0);
				break;
			}
		}
	}
#endif
}
 
static inline void del_from_runqueue(struct task_struct * p)
{
	struct task_struct *next = p->next_run;
	struct task_struct *prev = p->prev_run;
 
#if 1	/* sanity tests */
	if (!next || !prev) {
		printk("task not on run-queue\n");
		return;
	}
#endif
	if (p == &init_task) {
		static int nr = 0;
		if (nr < 5) {
			nr++;
			printk("idle task may not sleep\n");
		}
		return;
	}
	nr_running--;
	next->prev_run = prev;
	prev->next_run = next;
	p->next_run = NULL;
	p->prev_run = NULL;
}
 
static inline void move_last_runqueue(struct task_struct * p)
{
	struct task_struct *next = p->next_run;
	struct task_struct *prev = p->prev_run;
 
	/* remove from list */
	next->prev_run = prev;
	prev->next_run = next;
	/* add back to list */
	p->next_run = &init_task;
	prev = init_task.prev_run;
	init_task.prev_run = p;
	p->prev_run = prev;
	prev->next_run = p;
}
 
/*
 * Wake up a process. Put it on the run-queue if it's not
 * already there.  The "current" process is always on the
 * run-queue (except when the actual re-schedule is in
 * progress), and as such you're allowed to do the simpler
 * "current->state = TASK_RUNNING" to mark yourself runnable
 * without the overhead of this.
 */
inline void wake_up_process(struct task_struct * p)
{
	unsigned long flags;
 
	save_flags(flags);
	cli();
	p->state = TASK_RUNNING;
	if (!p->next_run)
		add_to_runqueue(p);
	restore_flags(flags);
}
 
static void process_timeout(unsigned long __data)
{
	struct task_struct * p = (struct task_struct *) __data;
 
	p->timeout = 0;
	wake_up_process(p);
}
 
/*
 * This is the function that decides how desirable a process is..
 * You can weigh different processes against each other depending
 * on what CPU they've run on lately etc to try to handle cache
 * and TLB miss penalties.
 *
 * Return values:
 *	 -1000: never select this
 *	     0: out of time, recalculate counters (but it might still be
 *		selected)
 *	   +ve: "goodness" value (the larger, the better)
 *	 +1000: realtime process, select this.
 */
static inline int goodness(struct task_struct * p, struct task_struct * prev, int this_cpu)
{
	int weight;
 
#ifdef __SMP__	
	/* We are not permitted to run a task someone else is running */
	if (p->processor != NO_PROC_ID)
		return -1000;
#ifdef PAST_2_0		
	/* This process is locked to a processor group */
	if (p->processor_mask && !(p->processor_mask & (1<<this_cpu))
		return -1000;
#endif		
#endif
 
	/*
	 * Realtime process, select the first one on the
	 * runqueue (taking priorities within processes
	 * into account).
	 */
	if (p->policy != SCHED_OTHER)
		return 1000 + p->rt_priority;
 
	/*
	 * Give the process a first-approximation goodness value
	 * according to the number of clock-ticks it has left.
	 *
	 * Don't do any other calculations if the time slice is
	 * over..
	 */
	weight = p->counter;
	if (weight) {
 
#ifdef __SMP__
		/* Give a largish advantage to the same processor...   */
		/* (this is equivalent to penalizing other processors) */
		if (p->last_processor == this_cpu)
			weight += PROC_CHANGE_PENALTY;
#endif
 
		/* .. and a slight advantage to the current process */
		if (p == prev)
			weight += 1;
	}
 
	return weight;
}
 
 
/*
  The following allow_interrupts function is used to workaround a rare but
  nasty deadlock situation that is possible for 2.0.x Intel SMP because it uses
  a single kernel lock and interrupts are only routed to the boot CPU.  There
  are two deadlock scenarios this code protects against.
 
  The first scenario is that if a CPU other than the boot CPU holds the kernel
  lock and needs to wait for an operation to complete that itself requires an
  interrupt, there is a deadlock since the boot CPU may be able to accept the
  interrupt but will not be able to acquire the kernel lock to process it.
 
  The workaround for this deadlock requires adding calls to allow_interrupts to
  places where this deadlock is possible.  These places are known to be present
  in buffer.c and keyboard.c.  It is also possible that there are other such
  places which have not been identified yet.  In order to break the deadlock,
  the code in allow_interrupts temporarily yields the kernel lock directly to
  the boot CPU to allow the interrupt to be processed.  The boot CPU interrupt
  entry code indicates that it is spinning waiting for the kernel lock by
  setting the smp_blocked_interrupt_pending variable.  This code notices that
  and manipulates the active_kernel_processor variable to yield the kernel lock
  without ever clearing it.  When the interrupt has been processed, the
  saved_active_kernel_processor variable contains the value for the interrupt
  exit code to restore, either the APICID of the CPU that granted it the kernel
  lock, or NO_PROC_ID in the normal case where no yielding occurred.  Restoring
  active_kernel_processor from saved_active_kernel_processor returns the kernel
  lock back to the CPU that yielded it.
 
  The second form of deadlock is even more insidious.  Suppose the boot CPU
  takes a page fault and then the previous scenario ensues.  In this case, the
  boot CPU would spin with interrupts disabled waiting to acquire the kernel
  lock.  To resolve this deadlock, the kernel lock acquisition code must enable
  interrupts briefly so that the pending interrupt can be handled as in the
  case above.
 
  An additional form of deadlock is where kernel code running on a non-boot CPU
  waits for the jiffies variable to be incremented.  This deadlock is avoided
  by having the spin loops in ENTER_KERNEL increment jiffies approximately
  every 10 milliseconds.  Finally, if approximately 60 seconds elapse waiting
  for the kernel lock, a message will be printed if possible to indicate that a
  deadlock has been detected.
 
		Leonard N. Zubkoff
		   4 August 1997
*/
 
#if defined(__SMP__) && defined(__i386__)
 
volatile unsigned char smp_blocked_interrupt_pending = 0;
 
volatile unsigned char saved_active_kernel_processor = NO_PROC_ID;
 
void allow_interrupts(void)
{
  if (smp_processor_id() == boot_cpu_id) return;
  if (smp_blocked_interrupt_pending)
    {
      unsigned long saved_kernel_counter;
      long timeout_counter;
      saved_active_kernel_processor = active_kernel_processor;
      saved_kernel_counter = kernel_counter;
      kernel_counter = 0;
      active_kernel_processor = boot_cpu_id;
      timeout_counter = 6000000;
      while (active_kernel_processor != saved_active_kernel_processor &&
	     --timeout_counter >= 0)
	{
	  udelay(10);
	  barrier();
	}
      if (timeout_counter < 0)
	panic("FORWARDED INTERRUPT TIMEOUT (AKP = %d, Saved AKP = %d)\n",
	      active_kernel_processor, saved_active_kernel_processor);
      kernel_counter = saved_kernel_counter;
      saved_active_kernel_processor = NO_PROC_ID;
    }
}
 
#else
 
void allow_interrupts(void) {}
 
#endif
 
 
/*
 *  'schedule()' is the scheduler function. It's a very simple and nice
 * scheduler: it's not perfect, but certainly works for most things.
 *
 * The goto is "interesting".
 *
 *   NOTE!!  Task 0 is the 'idle' task, which gets called when no other
 * tasks can run. It can not be killed, and it cannot sleep. The 'state'
 * information in task[0] is never used.
 */
asmlinkage void schedule(void)
{
	int c;
	struct task_struct * p;
	struct task_struct * prev, * next;
	unsigned long timeout = 0;
	int this_cpu=smp_processor_id();
/* check alarm, wake up any interruptible tasks that have got a signal */
 
	allow_interrupts();
 
	if (intr_count)
		goto scheduling_in_interrupt;
 
	if (bh_active & bh_mask) {
		intr_count = 1;
		do_bottom_half();
		intr_count = 0;
	}
 
	run_task_queue(&tq_scheduler);
 
	need_resched = 0;
	prev = current;
	cli();
	/* move an exhausted RR process to be last.. */
	if (!prev->counter && prev->policy == SCHED_RR) {
		prev->counter = prev->priority;
		move_last_runqueue(prev);
	}
	switch (prev->state) {
		case TASK_INTERRUPTIBLE:
			if (prev->signal & ~prev->blocked)
				goto makerunnable;
			timeout = prev->timeout;
			if (timeout && (timeout <= jiffies)) {
				prev->timeout = 0;
				timeout = 0;
		makerunnable:
				prev->state = TASK_RUNNING;
				break;
			}
		default:
			del_from_runqueue(prev);
		case TASK_RUNNING:
	}
	p = init_task.next_run;
	sti();
 
#ifdef __SMP__
	/*
	 *	This is safe as we do not permit re-entry of schedule()
	 */
	prev->processor = NO_PROC_ID;
#define idle_task (task[cpu_number_map[this_cpu]])
#else
#define idle_task (&init_task)
#endif	
 
/*
 * Note! there may appear new tasks on the run-queue during this, as
 * interrupts are enabled. However, they will be put on front of the
 * list, so our list starting at "p" is essentially fixed.
 */
/* this is the scheduler proper: */
	c = -1000;
	next = idle_task;
	while (p != &init_task) {
		int weight = goodness(p, prev, this_cpu);
		if (weight > c)
			c = weight, next = p;
		p = p->next_run;
	}
 
	/* if all runnable processes have "counter == 0", re-calculate counters */
	if (!c) {
		for_each_task(p)
			p->counter = (p->counter >> 1) + p->priority;
	}
#ifdef __SMP__
	/*
	 *	Allocate process to CPU
	 */
 
	 next->processor = this_cpu;
	 next->last_processor = this_cpu;
#endif	 
#ifdef __SMP_PROF__ 
	/* mark processor running an idle thread */
	if (0==next->pid)
		set_bit(this_cpu,&smp_idle_map);
	else
		clear_bit(this_cpu,&smp_idle_map);
#endif
	if (prev != next) {
		struct timer_list timer;
 
		kstat.context_swtch++;
		if (timeout) {
			init_timer(&timer);
			timer.expires = timeout;
			timer.data = (unsigned long) prev;
			timer.function = process_timeout;
			add_timer(&timer);
		}
		get_mmu_context(next);
		switch_to(prev,next);
		if (timeout)
			del_timer(&timer);
	}
	return;
 
scheduling_in_interrupt:
	printk("Aiee: scheduling in interrupt %p\n",
		__builtin_return_address(0));
}
 
#ifndef __alpha__
 
/*
 * For backwards compatibility?  This can be done in libc so Alpha
 * and all newer ports shouldn't need it.
 */
asmlinkage int sys_pause(void)
{
	current->state = TASK_INTERRUPTIBLE;
	schedule();
	return -ERESTARTNOHAND;
}
 
#endif
 
/*
 * wake_up doesn't wake up stopped processes - they have to be awakened
 * with signals or similar.
 *
 * Note that this doesn't need cli-sti pairs: interrupts may not change
 * the wait-queue structures directly, but only call wake_up() to wake
 * a process. The process itself must remove the queue once it has woken.
 */
void wake_up(struct wait_queue **q)
{
	struct wait_queue *next;
	struct wait_queue *head;
 
	if (!q || !(next = *q))
		return;
	head = WAIT_QUEUE_HEAD(q);
	while (next != head) {
		struct task_struct *p = next->task;
		next = next->next;
		if (p != NULL) {
			if ((p->state == TASK_UNINTERRUPTIBLE) ||
			    (p->state == TASK_INTERRUPTIBLE))
				wake_up_process(p);
		}
		if (!next)
			goto bad;
	}
	return;
bad:
	printk("wait_queue is bad (eip = %p)\n",
		__builtin_return_address(0));
	printk("        q = %p\n",q);
	printk("       *q = %p\n",*q);
}
 
void wake_up_interruptible(struct wait_queue **q)
{
	struct wait_queue *next;
	struct wait_queue *head;
 
	if (!q || !(next = *q))
		return;
	head = WAIT_QUEUE_HEAD(q);
	while (next != head) {
		struct task_struct *p = next->task;
		next = next->next;
		if (p != NULL) {
			if (p->state == TASK_INTERRUPTIBLE)
				wake_up_process(p);
		}
		if (!next)
			goto bad;
	}
	return;
bad:
	printk("wait_queue is bad (eip = %p)\n",
		__builtin_return_address(0));
	printk("        q = %p\n",q);
	printk("       *q = %p\n",*q);
}
 
 
/*
 * Semaphores are implemented using a two-way counter:
 * The "count" variable is decremented for each process
 * that tries to sleep, while the "waking" variable is
 * incremented when the "up()" code goes to wake up waiting
 * processes.
 *
 * Notably, the inline "up()" and "down()" functions can
 * efficiently test if they need to do any extra work (up
 * needs to do something only if count was negative before
 * the increment operation.
 *
 * This routine must execute atomically.
 */
static inline int waking_non_zero(struct semaphore *sem)
{
	int	ret ;
	long	flags ;
 
	get_buzz_lock(&sem->lock) ;
	save_flags(flags) ;
	cli() ;
 
	if ((ret = (sem->waking > 0)))
		sem->waking-- ;
 
	restore_flags(flags) ;
	give_buzz_lock(&sem->lock) ;
	return(ret) ;
}
 
/*
 * When __up() is called, the count was negative before
 * incrementing it, and we need to wake up somebody.
 *
 * This routine adds one to the count of processes that need to
 * wake up and exit.  ALL waiting processes actually wake up but
 * only the one that gets to the "waking" field first will gate
 * through and acquire the semaphore.  The others will go back
 * to sleep.
 *
 * Note that these functions are only called when there is
 * contention on the lock, and as such all this is the
 * "non-critical" part of the whole semaphore business. The
 * critical part is the inline stuff in <asm/semaphore.h>
 * where we want to avoid any extra jumps and calls.
 */
void __up(struct semaphore *sem)
{
	atomic_inc(&sem->waking) ;
	wake_up(&sem->wait);
}
 
/*
 * Perform the "down" function.  Return zero for semaphore acquired,
 * return negative for signalled out of the function.
 *
 * If called from __down, the return is ignored and the wait loop is
 * not interruptible.  This means that a task waiting on a semaphore
 * using "down()" cannot be killed until someone does an "up()" on
 * the semaphore.
 *
 * If called from __down_interruptible, the return value gets checked
 * upon return.  If the return value is negative then the task continues
 * with the negative value in the return register (it can be tested by
 * the caller).
 *
 * Either form may be used in conjunction with "up()".
 *
 */
int __do_down(struct semaphore * sem, int task_state)
{
	struct task_struct *tsk = current;
	struct wait_queue wait = { tsk, NULL };
	int		  ret = 0 ;
 
	tsk->state = task_state;
	add_wait_queue(&sem->wait, &wait);
 
	/*
	 * Ok, we're set up.  sem->count is known to be less than zero
	 * so we must wait.
	 *
	 * We can let go the lock for purposes of waiting.
	 * We re-acquire it after awaking so as to protect
	 * all semaphore operations.
	 *
	 * If "up()" is called before we call waking_non_zero() then
	 * we will catch it right away.  If it is called later then
	 * we will have to go through a wakeup cycle to catch it.
	 *
	 * Multiple waiters contend for the semaphore lock to see
	 * who gets to gate through and who has to wait some more.
	 */
	for (;;)
	{
		if (waking_non_zero(sem))	/* are we waking up?  */
		    break ;			/* yes, exit loop */
 
		if (   task_state == TASK_INTERRUPTIBLE
		    && (tsk->signal & ~tsk->blocked)	/* signalled */
		   )
		{
		    ret = -EINTR ;		/* interrupted */
		    atomic_inc(&sem->count) ;	/* give up on down operation */
		    break ;
		}
 
		schedule();
		tsk->state = task_state;
	}
 
	tsk->state = TASK_RUNNING;
	remove_wait_queue(&sem->wait, &wait);
	return(ret) ;
 
} /* __do_down */
 
void __down(struct semaphore * sem)
{
	__do_down(sem,TASK_UNINTERRUPTIBLE) ; 
}
 
int __down_interruptible(struct semaphore * sem)
{
	return(__do_down(sem,TASK_INTERRUPTIBLE)) ; 
}
 
 
static inline void __sleep_on(struct wait_queue **p, int state)
{
	unsigned long flags;
	struct wait_queue wait = { current, NULL };
 
	if (!p)
		return;
	if (current == task[0])
		panic("task[0] trying to sleep");
	current->state = state;
	save_flags(flags);
	cli();
	__add_wait_queue(p, &wait);
	sti();
	schedule();
	cli();
	__remove_wait_queue(p, &wait);
	restore_flags(flags);
}
 
void interruptible_sleep_on(struct wait_queue **p)
{
	__sleep_on(p,TASK_INTERRUPTIBLE);
}
 
void sleep_on(struct wait_queue **p)
{
	__sleep_on(p,TASK_UNINTERRUPTIBLE);
}
 
#define TVN_BITS 6
#define TVR_BITS 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)
 
#define SLOW_BUT_DEBUGGING_TIMERS 0
 
struct timer_vec {
        int index;
        struct timer_list *vec[TVN_SIZE];
};
 
struct timer_vec_root {
        int index;
        struct timer_list *vec[TVR_SIZE];
};
 
static struct timer_vec tv5 = { 0 };
static struct timer_vec tv4 = { 0 };
static struct timer_vec tv3 = { 0 };
static struct timer_vec tv2 = { 0 };
static struct timer_vec_root tv1 = { 0 };
 
static struct timer_vec * const tvecs[] = {
	(struct timer_vec *)&tv1, &tv2, &tv3, &tv4, &tv5
};
 
#define NOOF_TVECS (sizeof(tvecs) / sizeof(tvecs[0]))
 
static unsigned long timer_jiffies = 0;
 
static inline void insert_timer(struct timer_list *timer,
				struct timer_list **vec, int idx)
{
	if ((timer->next = vec[idx]))
		vec[idx]->prev = timer;
	vec[idx] = timer;
	timer->prev = (struct timer_list *)&vec[idx];
}
 
static inline void internal_add_timer(struct timer_list *timer)
{
	/*
	 * must be cli-ed when calling this
	 */
	unsigned long expires = timer->expires;
	unsigned long idx = expires - timer_jiffies;
 
	if (idx < TVR_SIZE) {
		int i = expires & TVR_MASK;
		insert_timer(timer, tv1.vec, i);
	} else if (idx < 1 << (TVR_BITS + TVN_BITS)) {
		int i = (expires >> TVR_BITS) & TVN_MASK;
		insert_timer(timer, tv2.vec, i);
	} else if (idx < 1 << (TVR_BITS + 2 * TVN_BITS)) {
		int i = (expires >> (TVR_BITS + TVN_BITS)) & TVN_MASK;
		insert_timer(timer, tv3.vec, i);
	} else if (idx < 1 << (TVR_BITS + 3 * TVN_BITS)) {
		int i = (expires >> (TVR_BITS + 2 * TVN_BITS)) & TVN_MASK;
		insert_timer(timer, tv4.vec, i);
	} else if (expires < timer_jiffies) {
		/* can happen if you add a timer with expires == jiffies,
		 * or you set a timer to go off in the past
		 */
		insert_timer(timer, tv1.vec, tv1.index);
	} else if (idx < 0xffffffffUL) {
		int i = (expires >> (TVR_BITS + 3 * TVN_BITS)) & TVN_MASK;
		insert_timer(timer, tv5.vec, i);
	} else {
		/* Can only get here on architectures with 64-bit jiffies */
		timer->next = timer->prev = timer;
	}
}
 
void add_timer(struct timer_list *timer)
{
	unsigned long flags;
	save_flags(flags);
	cli();
#if SLOW_BUT_DEBUGGING_TIMERS
        if (timer->next || timer->prev) {
                printk("add_timer() called with non-zero list from %p\n",
		       __builtin_return_address(0));
		goto out;
        }
#endif
	internal_add_timer(timer);
#if SLOW_BUT_DEBUGGING_TIMERS
out:
#endif
	restore_flags(flags);
}
 
static inline int detach_timer(struct timer_list *timer)
{
	int ret = 0;
	struct timer_list *next, *prev;
	next = timer->next;
	prev = timer->prev;
	if (next) {
		next->prev = prev;
	}
	if (prev) {
		ret = 1;
		prev->next = next;
	}
	return ret;
}
 
 
int del_timer(struct timer_list * timer)
{
	int ret;
	unsigned long flags;
	save_flags(flags);
	cli();
	ret = detach_timer(timer);
	timer->next = timer->prev = 0;
	restore_flags(flags);
	return ret;
}
 
static inline void cascade_timers(struct timer_vec *tv)
{
        /* cascade all the timers from tv up one level */
        struct timer_list *timer;
        timer = tv->vec[tv->index];
        /*
         * We are removing _all_ timers from the list, so we don't  have to
         * detach them individually, just clear the list afterwards.
         */
        while (timer) {
                struct timer_list *tmp = timer;
                timer = timer->next;
                internal_add_timer(tmp);
        }
        tv->vec[tv->index] = NULL;
        tv->index = (tv->index + 1) & TVN_MASK;
}
 
static inline void run_timer_list(void)
{
	cli();
	while ((long)(jiffies - timer_jiffies) >= 0) {
		struct timer_list *timer;
		if (!tv1.index) {
			int n = 1;
			do {
				cascade_timers(tvecs[n]);
			} while (tvecs[n]->index == 1 && ++n < NOOF_TVECS);
		}
		while ((timer = tv1.vec[tv1.index])) {
			void (*fn)(unsigned long) = timer->function;
			unsigned long data = timer->data;
			detach_timer(timer);
			timer->next = timer->prev = NULL;
			sti();
			fn(data);
			cli();
		}
		++timer_jiffies; 
		tv1.index = (tv1.index + 1) & TVR_MASK;
	}
	sti();
}
 
static inline void run_old_timers(void)
{
	struct timer_struct *tp;
	unsigned long mask;
 
	for (mask = 1, tp = timer_table+0 ; mask ; tp++,mask += mask) {
		if (mask > timer_active)
			break;
		if (!(mask & timer_active))
			continue;
		if (tp->expires > jiffies)
			continue;
		timer_active &= ~mask;
		tp->fn();
		sti();
	}
}
 
void tqueue_bh(void)
{
	run_task_queue(&tq_timer);
}
 
void immediate_bh(void)
{
	run_task_queue(&tq_immediate);
}
 
unsigned long timer_active = 0;
struct timer_struct timer_table[32];
 
/*
 * Hmm.. Changed this, as the GNU make sources (load.c) seems to
 * imply that avenrun[] is the standard name for this kind of thing.
 * Nothing else seems to be standardized: the fractional size etc
 * all seem to differ on different machines.
 */
unsigned long avenrun[3] = { 0,0,0 };
 
/*
 * Nr of active tasks - counted in fixed-point numbers
 */
static unsigned long count_active_tasks(void)
{
	struct task_struct **p;
	unsigned long nr = 0;
 
	for(p = &LAST_TASK; p > &FIRST_TASK; --p)
		if (*p && ((*p)->state == TASK_RUNNING ||
			   (*p)->state == TASK_UNINTERRUPTIBLE ||
			   (*p)->state == TASK_SWAPPING))
			nr += FIXED_1;
#ifdef __SMP__
	nr-=(smp_num_cpus-1)*FIXED_1;
#endif			
	return nr;
}
 
static inline void calc_load(unsigned long ticks)
{
	unsigned long active_tasks; /* fixed-point */
	static int count = LOAD_FREQ;
 
	count -= ticks;
	if (count < 0) {
		count += LOAD_FREQ;
		active_tasks = count_active_tasks();
		CALC_LOAD(avenrun[0], EXP_1, active_tasks);
		CALC_LOAD(avenrun[1], EXP_5, active_tasks);
		CALC_LOAD(avenrun[2], EXP_15, active_tasks);
	}
}
 
/*
 * this routine handles the overflow of the microsecond field
 *
 * The tricky bits of code to handle the accurate clock support
 * were provided by Dave Mills (Mills@UDEL.EDU) of NTP fame.
 * They were originally developed for SUN and DEC kernels.
 * All the kudos should go to Dave for this stuff.
 *
 */
static void second_overflow(void)
{
    long ltemp;
 
    /* Bump the maxerror field */
    time_maxerror += time_tolerance >> SHIFT_USEC;
    if ( time_maxerror > NTP_PHASE_LIMIT ) {
        time_maxerror = NTP_PHASE_LIMIT;
	time_state = TIME_ERROR;	/* p. 17, sect. 4.3, (b) */
	time_status |= STA_UNSYNC;
    }
 
    /*
     * Leap second processing. If in leap-insert state at
     * the end of the day, the system clock is set back one
     * second; if in leap-delete state, the system clock is
     * set ahead one second. The microtime() routine or
     * external clock driver will insure that reported time
     * is always monotonic. The ugly divides should be
     * replaced.
     */
    switch (time_state) {
 
    case TIME_OK:
	if (time_status & STA_INS)
	    time_state = TIME_INS;
	else if (time_status & STA_DEL)
	    time_state = TIME_DEL;
	break;
 
    case TIME_INS:
	if (xtime.tv_sec % 86400 == 0) {
	    xtime.tv_sec--;
	    time_state = TIME_OOP;
	    printk(KERN_NOTICE "Clock: inserting leap second 23:59:60 UTC\n");
	}
	break;
 
    case TIME_DEL:
	if ((xtime.tv_sec + 1) % 86400 == 0) {
	    xtime.tv_sec++;
	    time_state = TIME_WAIT;
	    printk(KERN_NOTICE "Clock: deleting leap second 23:59:59 UTC\n");
	}
	break;
 
    case TIME_OOP:
	time_state = TIME_WAIT;
	break;
 
    case TIME_WAIT:
	if (!(time_status & (STA_INS | STA_DEL)))
	    time_state = TIME_OK;
    }
 
    /*
     * Compute the phase adjustment for the next second. In
     * PLL mode, the offset is reduced by a fixed factor
     * times the time constant. In FLL mode the offset is
     * used directly. In either mode, the maximum phase
     * adjustment for each second is clamped so as to spread
     * the adjustment over not more than the number of
     * seconds between updates.
     */
    if (time_offset < 0) {
	ltemp = -time_offset;
	if (!(time_status & STA_FLL))
	    ltemp >>= SHIFT_KG + time_constant;
	if (ltemp > (MAXPHASE / MINSEC) << SHIFT_UPDATE)
	    ltemp = (MAXPHASE / MINSEC) << SHIFT_UPDATE;
	time_offset += ltemp;
	time_adj = -ltemp << (SHIFT_SCALE - SHIFT_HZ - SHIFT_UPDATE);
    } else {
	ltemp = time_offset;
	if (!(time_status & STA_FLL))
	    ltemp >>= SHIFT_KG + time_constant;
	if (ltemp > (MAXPHASE / MINSEC) << SHIFT_UPDATE)
	    ltemp = (MAXPHASE / MINSEC) << SHIFT_UPDATE;
	time_offset -= ltemp;
	time_adj = ltemp << (SHIFT_SCALE - SHIFT_HZ - SHIFT_UPDATE);
    }
 
    /*
     * Compute the frequency estimate and additional phase
     * adjustment due to frequency error for the next
     * second. When the PPS signal is engaged, gnaw on the
     * watchdog counter and update the frequency computed by
     * the pll and the PPS signal.
     */
    pps_valid++;
    if (pps_valid == PPS_VALID) {	/* PPS signal lost */
	pps_jitter = MAXTIME;
	pps_stabil = MAXFREQ;
	time_status &= ~(STA_PPSSIGNAL | STA_PPSJITTER |
			 STA_PPSWANDER | STA_PPSERROR);
    }
    ltemp = time_freq + pps_freq;
    if (ltemp < 0)
	time_adj -= -ltemp >> (SHIFT_USEC + SHIFT_HZ - SHIFT_SCALE);
    else
	time_adj +=  ltemp >> (SHIFT_USEC + SHIFT_HZ - SHIFT_SCALE);
 
#if HZ == 100
    /* Compensate for (HZ==100) != (1 << SHIFT_HZ).
     * Add 25% and 3.125% to get 128.125; => only 0.125% error (p. 14)
     */
    if (time_adj < 0)
	time_adj -= (-time_adj >> 2) + (-time_adj >> 5);
    else
	time_adj += (time_adj >> 2) + (time_adj >> 5);
#endif
}
 
/* in the NTP reference this is called "hardclock()" */
static void update_wall_time_one_tick(void)
{
	if ( (time_adjust_step = time_adjust) != 0 ) {
	    /* We are doing an adjtime thing. 
	     *
	     * Prepare time_adjust_step to be within bounds.
	     * Note that a positive time_adjust means we want the clock
	     * to run faster.
	     *
	     * Limit the amount of the step to be in the range
	     * -tickadj .. +tickadj
	     */
	     if (time_adjust > tickadj)
		time_adjust_step = tickadj;
	     else if (time_adjust < -tickadj)
		time_adjust_step = -tickadj;
 
	    /* Reduce by this step the amount of time left  */
	    time_adjust -= time_adjust_step;
	}
	xtime.tv_usec += tick + time_adjust_step;
	/*
	 * Advance the phase, once it gets to one microsecond, then
	 * advance the tick more.
	 */
	time_phase += time_adj;
	if (time_phase <= -FINEUSEC) {
		long ltemp = -time_phase >> SHIFT_SCALE;
		time_phase += ltemp << SHIFT_SCALE;
		xtime.tv_usec -= ltemp;
	}
	else if (time_phase >= FINEUSEC) {
		long ltemp = time_phase >> SHIFT_SCALE;
		time_phase -= ltemp << SHIFT_SCALE;
		xtime.tv_usec += ltemp;
	}
}
 
/*
 * Using a loop looks inefficient, but "ticks" is
 * usually just one (we shouldn't be losing ticks,
 * we're doing this this way mainly for interrupt
 * latency reasons, not because we think we'll
 * have lots of lost timer ticks
 */
static void update_wall_time(unsigned long ticks)
{
	do {
		ticks--;
		update_wall_time_one_tick();
	} while (ticks);
 
	if (xtime.tv_usec >= 1000000) {
	    xtime.tv_usec -= 1000000;
	    xtime.tv_sec++;
	    second_overflow();
	}
}
 
static inline void do_process_times(struct task_struct *p,
	unsigned long user, unsigned long system)
{
	long psecs;
 
	p->utime += user;
	p->stime += system;
 
	psecs = (p->stime + p->utime) / HZ;
	if (psecs > p->rlim[RLIMIT_CPU].rlim_cur) {
		/* Send SIGXCPU every second.. */
		if (psecs * HZ == p->stime + p->utime)
			send_sig(SIGXCPU, p, 1);
		/* and SIGKILL when we go over max.. */
		if (psecs > p->rlim[RLIMIT_CPU].rlim_max)
			send_sig(SIGKILL, p, 1);
	}
}
 
static inline void do_it_virt(struct task_struct * p, unsigned long ticks)
{
	unsigned long it_virt = p->it_virt_value;
 
	if (it_virt) {
		if (it_virt <= ticks) {
			it_virt = ticks + p->it_virt_incr;
			send_sig(SIGVTALRM, p, 1);
		}
		p->it_virt_value = it_virt - ticks;
	}
}
 
static inline void do_it_prof(struct task_struct * p, unsigned long ticks)
{
	unsigned long it_prof = p->it_prof_value;
 
	if (it_prof) {
		if (it_prof <= ticks) {
			it_prof = ticks + p->it_prof_incr;
			send_sig(SIGPROF, p, 1);
		}
		p->it_prof_value = it_prof - ticks;
	}
}
 
static __inline__ void update_one_process(struct task_struct *p,
	unsigned long ticks, unsigned long user, unsigned long system)
{
	do_process_times(p, user, system);
	do_it_virt(p, user);
	do_it_prof(p, ticks);
}	
 
static void update_process_times(unsigned long ticks, unsigned long system)
{
#ifndef  __SMP__
	struct task_struct * p = current;
	unsigned long user = ticks - system;
	if (p->pid) {
		p->counter -= ticks;
		if (p->counter < 0) {
			p->counter = 0;
			need_resched = 1;
		}
		if (p->priority < DEF_PRIORITY)
			kstat.cpu_nice += user;
		else
			kstat.cpu_user += user;
		kstat.cpu_system += system;
	}
	update_one_process(p, ticks, user, system);
#else
	int cpu,j;
	cpu = smp_processor_id();
	for (j=0;j<smp_num_cpus;j++)
	{
		int i = cpu_logical_map[j];
		struct task_struct *p;
 
#ifdef __SMP_PROF__
		if (test_bit(i,&smp_idle_map)) 
			smp_idle_count[i]++;
#endif
		p = current_set[i];
		/*
		 * Do we have a real process?
		 */
		if (p->pid) {
			/* assume user-mode process */
			unsigned long utime = ticks;
			unsigned long stime = 0;
			if (cpu == i) {
				utime = ticks-system;
				stime = system;
			} else if (smp_proc_in_lock[j]) {
				utime = 0;
				stime = ticks;
			}
			update_one_process(p, ticks, utime, stime);
 
			if (p->priority < DEF_PRIORITY)
				kstat.cpu_nice += utime;
			else
				kstat.cpu_user += utime;
			kstat.cpu_system += stime;
 
			p->counter -= ticks;
			if (p->counter >= 0)
				continue;
			p->counter = 0;
		} else {
			/*
			 * Idle processor found, do we have anything
			 * we could run?
			 */
			if (!(0x7fffffff & smp_process_available))
				continue;
		}
		/* Ok, we should reschedule, do the magic */
		if (i==cpu)
			need_resched = 1;
		else
			smp_message_pass(i, MSG_RESCHEDULE, 0L, 0);
	}
#endif
}
 
static unsigned long lost_ticks = 0;
static unsigned long lost_ticks_system = 0;
 
static inline void update_times(void)
{
	unsigned long ticks;
 
	ticks = xchg(&lost_ticks, 0);
 
	if (ticks) {
		unsigned long system;
 
		system = xchg(&lost_ticks_system, 0);
		calc_load(ticks);
		update_wall_time(ticks);
		update_process_times(ticks, system);
	}
}
 
void timer_bh(void)
{
	update_times();
	run_old_timers();
	run_timer_list();
}
 
void do_timer(struct pt_regs * regs)
{
	(*(unsigned long *)&jiffies)++;
	lost_ticks++;
	mark_bh(TIMER_BH);
	if (!user_mode(regs)) {
		lost_ticks_system++;
		if (prof_buffer && current->pid) {
			extern int _stext;
			unsigned long ip = instruction_pointer(regs);
			ip -= (unsigned long) &_stext;
			ip >>= prof_shift;
			if (ip < prof_len)
				prof_buffer[ip]++;
		}
	}
	if (tq_timer)
		mark_bh(TQUEUE_BH);
}
 
#ifndef __alpha__
 
/*
 * For backwards compatibility?  This can be done in libc so Alpha
 * and all newer ports shouldn't need it.
 */
asmlinkage unsigned int sys_alarm(unsigned int seconds)
{
	struct itimerval it_new, it_old;
	unsigned int oldalarm;
 
	it_new.it_interval.tv_sec = it_new.it_interval.tv_usec = 0;
	it_new.it_value.tv_sec = seconds;
	it_new.it_value.tv_usec = 0;
	_setitimer(ITIMER_REAL, &it_new, &it_old);
	oldalarm = it_old.it_value.tv_sec;
	/* ehhh.. We can't return 0 if we have an alarm pending.. */
	/* And we'd better return too much than too little anyway */
	if (it_old.it_value.tv_usec)
		oldalarm++;
	return oldalarm;
}
 
/*
 * The Alpha uses getxpid, getxuid, and getxgid instead.  Maybe this
 * should be moved into arch/i386 instead?
 */
asmlinkage int sys_getpid(void)
{
	return current->pid;
}
 
asmlinkage int sys_getppid(void)
{
	return current->p_opptr->pid;
}
 
asmlinkage int sys_getuid(void)
{
	return current->uid;
}
 
asmlinkage int sys_geteuid(void)
{
	return current->euid;
}
 
asmlinkage int sys_getgid(void)
{
	return current->gid;
}
 
asmlinkage int sys_getegid(void)
{
	return current->egid;
}
 
/*
 * This has been replaced by sys_setpriority.  Maybe it should be
 * moved into the arch dependent tree for those ports that require
 * it for backward compatibility?
 */
asmlinkage int sys_nice(int increment)
{
	unsigned long newprio;
	int increase = 0;
 
	newprio = increment;
	if (increment < 0) {
		if (!suser())
			return -EPERM;
		newprio = -increment;
		increase = 1;
	}
	if (newprio > 40)
		newprio = 40;
	/*
	 * do a "normalization" of the priority (traditionally
	 * unix nice values are -20..20, linux doesn't really
	 * use that kind of thing, but uses the length of the
	 * timeslice instead (default 150 msec). The rounding is
	 * why we want to avoid negative values.
	 */
	newprio = (newprio * DEF_PRIORITY + 10) / 20;
	increment = newprio;
	if (increase)
		increment = -increment;
	newprio = current->priority - increment;
	if ((signed) newprio < 1)
		newprio = 1;
	if (newprio > DEF_PRIORITY*2)
		newprio = DEF_PRIORITY*2;
	current->priority = newprio;
	return 0;
}
 
#endif
 
static struct task_struct *find_process_by_pid(pid_t pid) {
	struct task_struct *p, *q;
 
	if (pid == 0)
		p = current;
	else {
		p = 0;
		for_each_task(q) {
			if (q && q->pid == pid) {
				p = q;
				break;
			}
		}
	}
	return p;
}
 
static int setscheduler(pid_t pid, int policy, 
			struct sched_param *param)
{
	int error;
	struct sched_param lp;
	struct task_struct *p;
 
	if (!param || pid < 0)
		return -EINVAL;
 
	error = verify_area(VERIFY_READ, param, sizeof(struct sched_param));
	if (error)
		return error;
	memcpy_fromfs(&lp, param, sizeof(struct sched_param));
 
	p = find_process_by_pid(pid);
	if (!p)
		return -ESRCH;
 
	if (policy < 0)
		policy = p->policy;
	else if (policy != SCHED_FIFO && policy != SCHED_RR &&
		 policy != SCHED_OTHER)
		return -EINVAL;
 
	/*
	 * Valid priorities for SCHED_FIFO and SCHED_RR are 1..99, valid
	 * priority for SCHED_OTHER is 0.
	 */
	if (lp.sched_priority < 0 || lp.sched_priority > 99)
		return -EINVAL;
	if ((policy == SCHED_OTHER) != (lp.sched_priority == 0))
		return -EINVAL;
 
	if ((policy == SCHED_FIFO || policy == SCHED_RR) && !suser())
		return -EPERM;
	if ((current->euid != p->euid) && (current->euid != p->uid) &&
	    !suser())
		return -EPERM;
 
	p->policy = policy;
	p->rt_priority = lp.sched_priority;
	cli();
	if (p->next_run)
		move_last_runqueue(p);
	sti();
	need_resched = 1;
	return 0;
}
 
asmlinkage int sys_sched_setscheduler(pid_t pid, int policy, 
				      struct sched_param *param)
{
	return setscheduler(pid, policy, param);
}
 
asmlinkage int sys_sched_setparam(pid_t pid, struct sched_param *param)
{
	return setscheduler(pid, -1, param);
}
 
asmlinkage int sys_sched_getscheduler(pid_t pid)
{
	struct task_struct *p;
 
	if (pid < 0)
		return -EINVAL;
 
	p = find_process_by_pid(pid);
	if (!p)
		return -ESRCH;
 
	return p->policy;
}
 
asmlinkage int sys_sched_getparam(pid_t pid, struct sched_param *param)
{
	int error;
	struct task_struct *p;
	struct sched_param lp;
 
	if (!param || pid < 0)
		return -EINVAL;
 
	error = verify_area(VERIFY_WRITE, param, sizeof(struct sched_param));
	if (error)
		return error;
 
	p = find_process_by_pid(pid);
	if (!p)
		return -ESRCH;
 
	lp.sched_priority = p->rt_priority;
	memcpy_tofs(param, &lp, sizeof(struct sched_param));
 
	return 0;
}
 
asmlinkage int sys_sched_yield(void)
{
	cli();
	move_last_runqueue(current);
	current->counter = 0;
	need_resched = 1;
	sti();
	return 0;
}
 
asmlinkage int sys_sched_get_priority_max(int policy)
{
	switch (policy) {
	      case SCHED_FIFO:
	      case SCHED_RR:
		return 99;
	      case SCHED_OTHER:
		return 0;
	}
 
	return -EINVAL;
}
 
asmlinkage int sys_sched_get_priority_min(int policy)
{
	switch (policy) {
	      case SCHED_FIFO:
	      case SCHED_RR:
		return 1;
	      case SCHED_OTHER:
		return 0;
	}
 
	return -EINVAL;
}
 
asmlinkage int sys_sched_rr_get_interval(pid_t pid, struct timespec *interval)
{
	int error;
	struct timespec t;
 
	error = verify_area(VERIFY_WRITE, interval, sizeof(struct timespec));
	if (error)
		return error;
 
	/* Values taken from 2.1.38 */	
	t.tv_sec = 0;
	t.tv_nsec = 150000;   /* is this right for non-intel architecture too?*/
	memcpy_tofs(interval, &t, sizeof(struct timespec));
 
	return 0;
}
 
/*
 * change timeval to jiffies, trying to avoid the 
 * most obvious overflows..
 */
static unsigned long timespectojiffies(struct timespec *value)
{
	unsigned long sec = (unsigned) value->tv_sec;
	long nsec = value->tv_nsec;
 
	if (sec > (LONG_MAX / HZ))
		return LONG_MAX;
	nsec += 1000000000L / HZ - 1;
	nsec /= 1000000000L / HZ;
	return HZ * sec + nsec;
}
 
static void jiffiestotimespec(unsigned long jiffies, struct timespec *value)
{
	value->tv_nsec = (jiffies % HZ) * (1000000000L / HZ);
	value->tv_sec = jiffies / HZ;
	return;
}
 
asmlinkage int sys_nanosleep(struct timespec *rqtp, struct timespec *rmtp)
{
	int error;
	struct timespec t;
	unsigned long expire;
 
	error = verify_area(VERIFY_READ, rqtp, sizeof(struct timespec));
	if (error)
		return error;
	memcpy_fromfs(&t, rqtp, sizeof(struct timespec));
	if (rmtp) {
		error = verify_area(VERIFY_WRITE, rmtp,
				    sizeof(struct timespec));
		if (error)
			return error;
	}
 
	if (t.tv_nsec >= 1000000000L || t.tv_nsec < 0 || t.tv_sec < 0)
		return -EINVAL;
 
	if (t.tv_sec == 0 && t.tv_nsec <= 2000000L &&
	    current->policy != SCHED_OTHER) {
		/*
		 * Short delay requests up to 2 ms will be handled with
		 * high precision by a busy wait for all real-time processes.
		 */
		udelay((t.tv_nsec + 999) / 1000);
		return 0;
	}
 
	expire = timespectojiffies(&t) + (t.tv_sec || t.tv_nsec) + jiffies;
	current->timeout = expire;
	current->state = TASK_INTERRUPTIBLE;
	schedule();
 
	if (expire > jiffies) {
		if (rmtp) {
			jiffiestotimespec(expire - jiffies -
					  (expire > jiffies + 1), &t);
			memcpy_tofs(rmtp, &t, sizeof(struct timespec));
		}
		return -EINTR;
	}
 
	return 0;
}
 
/* Used in fs/proc/array.c */
unsigned long get_wchan(struct task_struct *p)
{
	if (!p || p == current || p->state == TASK_RUNNING)
		return 0;
#if defined(__i386__)
	{
		unsigned long ebp, eip;
		unsigned long stack_page;
		int count = 0;
 
		stack_page = p->kernel_stack_page;
		if (!stack_page)
			return 0;
		ebp = p->tss.ebp;
		do {
			if (ebp < stack_page || ebp >= 4092+stack_page)
				return 0;
			eip = *(unsigned long *) (ebp+4);
			if (eip < (unsigned long) interruptible_sleep_on
			    || eip >= (unsigned long) add_timer)
				return eip;
			ebp = *(unsigned long *) ebp;
		} while (count++ < 16);
	}
#elif defined(__alpha__)
	/*
	 * This one depends on the frame size of schedule().  Do a
	 * "disass schedule" in gdb to find the frame size.  Also, the
	 * code assumes that sleep_on() follows immediately after
	 * interruptible_sleep_on() and that add_timer() follows
	 * immediately after interruptible_sleep().  Ugly, isn't it?
	 * Maybe adding a wchan field to task_struct would be better,
	 * after all...
	 */
	{
	    unsigned long schedule_frame;
	    unsigned long pc;
 
	    pc = thread_saved_pc(&p->tss);
	    if (pc >= (unsigned long) interruptible_sleep_on && pc < (unsigned long) add_timer) {
		schedule_frame = ((unsigned long *)p->tss.ksp)[6];
		return ((unsigned long *)schedule_frame)[12];
	    }
	    return pc;
	}
#endif
	return 0;
}
 
static void show_task(int nr,struct task_struct * p)
{
	unsigned long free;
	static const char * stat_nam[] = { "R", "S", "D", "Z", "T", "W" };
 
	printk("%-8s %3d ", p->comm, (p == current) ? -nr : nr);
	if (((unsigned) p->state) < sizeof(stat_nam)/sizeof(char *))
		printk(stat_nam[p->state]);
	else
		printk(" ");
#if ((~0UL) == 0xffffffff)
	if (p == current)
		printk(" current  ");
	else
		printk(" %08lX ", thread_saved_pc(&p->tss));
	printk("%08lX ", get_wchan(p));
#else
	if (p == current)
		printk("   current task   ");
	else
		printk(" %016lx ", thread_saved_pc(&p->tss));
	printk("%08lX ", get_wchan(p) & 0xffffffffL);
#endif
	if (((unsigned long *)p->kernel_stack_page)[0] != STACK_MAGIC)
		printk(" bad-");
 
	for (free = 1; free < PAGE_SIZE/sizeof(long) ; free++) {
		if (((unsigned long *)p->kernel_stack_page)[free] != STACK_UNTOUCHED_MAGIC)
			break;
	}
	printk("%5lu %5d %6d ", free*sizeof(long), p->pid, p->p_pptr->pid);
	if (p->p_cptr)
		printk("%5d ", p->p_cptr->pid);
	else
		printk("      ");
	if (p->p_ysptr)
		printk("%7d", p->p_ysptr->pid);
	else
		printk("       ");
	if (p->p_osptr)
		printk(" %5d\n", p->p_osptr->pid);
	else
		printk("\n");
}
 
void show_state(void)
{
	int i;
 
#if ((~0UL) == 0xffffffff)
	printk("\n"
	       "                                  free                        sibling\n");
	printk("  task             PC     wchan   stack   pid father child younger older\n");
#else
	printk("\n"
	       "                                           free                        sibling\n");
	printk("  task                 PC         wchan    stack   pid father child younger older\n");
#endif
	for (i=0 ; i<NR_TASKS ; i++)
		if (task[i])
			show_task(i,task[i]);
}
 
void sched_init(void)
{
	/*
	 *	We have to do a little magic to get the first
	 *	process right in SMP mode.
	 */
	int cpu=smp_processor_id();
	int i;
#ifndef __SMP__	
	current_set[cpu]=&init_task;
#else
	init_task.processor=cpu;
	for(cpu = 0; cpu < NR_CPUS; cpu++)
		current_set[cpu] = &init_task;
#endif
 
	init_kernel_stack[0] = STACK_MAGIC;
	for(i=1;i<1024;i++)
		init_kernel_stack[i] = STACK_UNTOUCHED_MAGIC;
 
	init_bh(TIMER_BH, timer_bh);
	init_bh(TQUEUE_BH, tqueue_bh);
	init_bh(IMMEDIATE_BH, immediate_bh);
}