Bare uClinux-2.4.20-uc1 CVS pull

1 files changed, 876 insertions, 0 deletions

diff --git a/uClinux-2.4.20-uc1/kernel/timer.c b/uClinux-2.4.20-uc1/kernel/timer.c
new file mode 100644
index 0000000..1c626d5
--- /dev/null
+++ b/uClinux-2.4.20-uc1/kernel/timer.c
@@ -0,0 +1,876 @@
+/*
+ *  linux/kernel/timer.c
+ *
+ *  Kernel internal timers, kernel timekeeping, 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
+ */
+
+#include <linux/config.h>
+#include <linux/mm.h>
+#include <linux/timex.h>
+#include <linux/delay.h>
+#include <linux/smp_lock.h>
+#include <linux/interrupt.h>
+#include <linux/kernel_stat.h>
+
+#include <asm/uaccess.h>
+
+/*
+ * Timekeeping variables
+ */
+
+long tick = (1000000 + HZ/2) / HZ;	/* timer interrupt period */
+
+/* The current time */
+struct timeval xtime __attribute__ ((aligned (16)));
+
+/* Don't completely fail for HZ > 500.  */
+int tickadj = 500/HZ ? : 1;		/* microsecs */
+
+DECLARE_TASK_QUEUE(tq_timer);
+DECLARE_TASK_QUEUE(tq_immediate);
+
+/*
+ * phase-lock loop variables
+ */
+/* TIME_ERROR prevents overwriting the CMOS clock */
+int time_state = TIME_OK;		/* clock synchronization status	*/
+int time_status = STA_UNSYNC;		/* clock status bits		*/
+long time_offset;			/* 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;			/* phase offset (scaled us)	*/
+long time_freq = ((1000000 + HZ/2) % HZ - HZ/2) << SHIFT_USEC;
+					/* frequency offset (scaled ppm)*/
+long time_adj;				/* tick adjust (scaled 1 / HZ)	*/
+long time_reftime;			/* time at last adjustment (s)	*/
+
+long time_adjust;
+long time_adjust_step;
+
+unsigned long event;
+
+extern int do_setitimer(int, struct itimerval *, struct itimerval *);
+
+unsigned long volatile jiffies;
+
+unsigned int * prof_buffer;
+unsigned long prof_len;
+unsigned long prof_shift;
+
+/*
+ * Event timer code
+ */
+#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)
+
+struct timer_vec {
+	int index;
+	struct list_head vec[TVN_SIZE];
+};
+
+struct timer_vec_root {
+	int index;
+	struct list_head vec[TVR_SIZE];
+};
+
+static struct timer_vec tv5;
+static struct timer_vec tv4;
+static struct timer_vec tv3;
+static struct timer_vec tv2;
+static struct timer_vec_root tv1;
+
+static struct timer_vec * const tvecs[] = {
+	(struct timer_vec *)&tv1, &tv2, &tv3, &tv4, &tv5
+};
+
+static struct list_head * run_timer_list_running;
+
+#define NOOF_TVECS (sizeof(tvecs) / sizeof(tvecs[0]))
+
+void init_timervecs (void)
+{
+	int i;
+
+	for (i = 0; i < TVN_SIZE; i++) {
+		INIT_LIST_HEAD(tv5.vec + i);
+		INIT_LIST_HEAD(tv4.vec + i);
+		INIT_LIST_HEAD(tv3.vec + i);
+		INIT_LIST_HEAD(tv2.vec + i);
+	}
+	for (i = 0; i < TVR_SIZE; i++)
+		INIT_LIST_HEAD(tv1.vec + i);
+}
+
+static unsigned long timer_jiffies;
+
+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;
+	struct list_head * vec;
+
+	if (run_timer_list_running)
+		vec = run_timer_list_running;
+	else if (idx < TVR_SIZE) {
+		int i = expires & TVR_MASK;
+		vec = tv1.vec + i;
+	} else if (idx < 1 << (TVR_BITS + TVN_BITS)) {
+		int i = (expires >> TVR_BITS) & TVN_MASK;
+		vec = tv2.vec + i;
+	} else if (idx < 1 << (TVR_BITS + 2 * TVN_BITS)) {
+		int i = (expires >> (TVR_BITS + TVN_BITS)) & TVN_MASK;
+		vec =  tv3.vec + i;
+	} else if (idx < 1 << (TVR_BITS + 3 * TVN_BITS)) {
+		int i = (expires >> (TVR_BITS + 2 * TVN_BITS)) & TVN_MASK;
+		vec = tv4.vec + i;
+	} else if ((signed long) idx < 0) {
+		/* can happen if you add a timer with expires == jiffies,
+		 * or you set a timer to go off in the past
+		 */
+		vec = tv1.vec + tv1.index;
+	} else if (idx <= 0xffffffffUL) {
+		int i = (expires >> (TVR_BITS + 3 * TVN_BITS)) & TVN_MASK;
+		vec = tv5.vec + i;
+	} else {
+		/* Can only get here on architectures with 64-bit jiffies */
+		INIT_LIST_HEAD(&timer->list);
+		return;
+	}
+	/*
+	 * Timers are FIFO!
+	 */
+	list_add(&timer->list, vec->prev);
+}
+
+/* Initialize both explicitly - let's try to have them in the same cache line */
+spinlock_t timerlist_lock = SPIN_LOCK_UNLOCKED;
+
+#ifdef CONFIG_SMP
+volatile struct timer_list * volatile running_timer;
+#define timer_enter(t) do { running_timer = t; mb(); } while (0)
+#define timer_exit() do { running_timer = NULL; } while (0)
+#define timer_is_running(t) (running_timer == t)
+#define timer_synchronize(t) while (timer_is_running(t)) barrier()
+#else
+#define timer_enter(t)		do { } while (0)
+#define timer_exit()		do { } while (0)
+#endif
+
+void add_timer(struct timer_list *timer)
+{
+	unsigned long flags;
+
+	spin_lock_irqsave(&timerlist_lock, flags);
+	if (timer_pending(timer))
+		goto bug;
+	internal_add_timer(timer);
+	spin_unlock_irqrestore(&timerlist_lock, flags);
+	return;
+bug:
+	spin_unlock_irqrestore(&timerlist_lock, flags);
+	printk("bug: kernel timer added twice at %p.\n",
+			__builtin_return_address(0));
+}
+
+static inline int detach_timer (struct timer_list *timer)
+{
+	if (!timer_pending(timer))
+		return 0;
+	list_del(&timer->list);
+	return 1;
+}
+
+int mod_timer(struct timer_list *timer, unsigned long expires)
+{
+	int ret;
+	unsigned long flags;
+
+	spin_lock_irqsave(&timerlist_lock, flags);
+	timer->expires = expires;
+	ret = detach_timer(timer);
+	internal_add_timer(timer);
+	spin_unlock_irqrestore(&timerlist_lock, flags);
+	return ret;
+}
+
+int del_timer(struct timer_list * timer)
+{
+	int ret;
+	unsigned long flags;
+
+	spin_lock_irqsave(&timerlist_lock, flags);
+	ret = detach_timer(timer);
+	timer->list.next = timer->list.prev = NULL;
+	spin_unlock_irqrestore(&timerlist_lock, flags);
+	return ret;
+}
+
+#ifdef CONFIG_SMP
+void sync_timers(void)
+{
+	spin_unlock_wait(&global_bh_lock);
+}
+
+/*
+ * SMP specific function to delete periodic timer.
+ * Caller must disable by some means restarting the timer
+ * for new. Upon exit the timer is not queued and handler is not running
+ * on any CPU. It returns number of times, which timer was deleted
+ * (for reference counting).
+ */
+
+int del_timer_sync(struct timer_list * timer)
+{
+	int ret = 0;
+
+	for (;;) {
+		unsigned long flags;
+		int running;
+
+		spin_lock_irqsave(&timerlist_lock, flags);
+		ret += detach_timer(timer);
+		timer->list.next = timer->list.prev = 0;
+		running = timer_is_running(timer);
+		spin_unlock_irqrestore(&timerlist_lock, flags);
+
+		if (!running)
+			break;
+
+		timer_synchronize(timer);
+	}
+
+	return ret;
+}
+#endif
+
+
+static inline void cascade_timers(struct timer_vec *tv)
+{
+	/* cascade all the timers from tv up one level */
+	struct list_head *head, *curr, *next;
+
+	head = tv->vec + tv->index;
+	curr = head->next;
+	/*
+	 * We are removing _all_ timers from the list, so we don't  have to
+	 * detach them individually, just clear the list afterwards.
+	 */
+	while (curr != head) {
+		struct timer_list *tmp;
+
+		tmp = list_entry(curr, struct timer_list, list);
+		next = curr->next;
+		list_del(curr); // not needed
+		internal_add_timer(tmp);
+		curr = next;
+	}
+	INIT_LIST_HEAD(head);
+	tv->index = (tv->index + 1) & TVN_MASK;
+}
+
+static inline void run_timer_list(void)
+{
+	spin_lock_irq(&timerlist_lock);
+	while ((long)(jiffies - timer_jiffies) >= 0) {
+		LIST_HEAD(queued);
+		struct list_head *head, *curr;
+		if (!tv1.index) {
+			int n = 1;
+			do {
+				cascade_timers(tvecs[n]);
+			} while (tvecs[n]->index == 1 && ++n < NOOF_TVECS);
+		}
+		run_timer_list_running = &queued;
+repeat:
+		head = tv1.vec + tv1.index;
+		curr = head->next;
+		if (curr != head) {
+			struct timer_list *timer;
+			void (*fn)(unsigned long);
+			unsigned long data;
+
+			timer = list_entry(curr, struct timer_list, list);
+ 			fn = timer->function;
+ 			data= timer->data;
+
+			detach_timer(timer);
+			timer->list.next = timer->list.prev = NULL;
+			timer_enter(timer);
+			spin_unlock_irq(&timerlist_lock);
+			fn(data);
+			spin_lock_irq(&timerlist_lock);
+			timer_exit();
+			goto repeat;
+		}
+		run_timer_list_running = NULL;
+		++timer_jiffies; 
+		tv1.index = (tv1.index + 1) & TVR_MASK;
+
+		curr = queued.next;
+		while (curr != &queued) {
+			struct timer_list *timer;
+
+			timer = list_entry(curr, struct timer_list, list);
+			curr = curr->next;
+			internal_add_timer(timer);
+		}			
+	}
+	spin_unlock_irq(&timerlist_lock);
+}
+
+spinlock_t tqueue_lock = SPIN_LOCK_UNLOCKED;
+
+void tqueue_bh(void)
+{
+	run_task_queue(&tq_timer);
+}
+
+void immediate_bh(void)
+{
+	run_task_queue(&tq_immediate);
+}
+
+/*
+ * 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_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)
+{
+	unsigned long psecs;
+
+	psecs = (p->times.tms_utime += user);
+	psecs += (p->times.tms_stime += system);
+	if (psecs / HZ > p->rlim[RLIMIT_CPU].rlim_cur) {
+		/* Send SIGXCPU every second.. */
+		if (!(psecs % HZ))
+			send_sig(SIGXCPU, p, 1);
+		/* and SIGKILL when we go over max.. */
+		if (psecs / HZ > 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) {
+		it_virt -= ticks;
+		if (!it_virt) {
+			it_virt = p->it_virt_incr;
+			send_sig(SIGVTALRM, p, 1);
+		}
+		p->it_virt_value = it_virt;
+	}
+}
+
+static inline void do_it_prof(struct task_struct *p)
+{
+	unsigned long it_prof = p->it_prof_value;
+
+	if (it_prof) {
+		if (--it_prof == 0) {
+			it_prof = p->it_prof_incr;
+			send_sig(SIGPROF, p, 1);
+		}
+		p->it_prof_value = it_prof;
+	}
+}
+
+void update_one_process(struct task_struct *p, unsigned long user,
+			unsigned long system, int cpu)
+{
+	p->per_cpu_utime[cpu] += user;
+	p->per_cpu_stime[cpu] += system;
+	do_process_times(p, user, system);
+	do_it_virt(p, user);
+	do_it_prof(p);
+}	
+
+/*
+ * Called from the timer interrupt handler to charge one tick to the current 
+ * process.  user_tick is 1 if the tick is user time, 0 for system.
+ */
+void update_process_times(int user_tick)
+{
+	struct task_struct *p = current;
+	int cpu = smp_processor_id(), system = user_tick ^ 1;
+
+	update_one_process(p, user_tick, system, cpu);
+	if (p->pid) {
+		if (--p->counter <= 0) {
+			p->counter = 0;
+			/*
+			 * SCHED_FIFO is priority preemption, so this is 
+			 * not the place to decide whether to reschedule a
+			 * SCHED_FIFO task or not - Bhavesh Davda
+			 */
+			if (p->policy != SCHED_FIFO) {
+				p->need_resched = 1;
+			}
+		}
+		if (p->nice > 0)
+			kstat.per_cpu_nice[cpu] += user_tick;
+		else
+			kstat.per_cpu_user[cpu] += user_tick;
+		kstat.per_cpu_system[cpu] += system;
+	} else if (local_bh_count(cpu) || local_irq_count(cpu) > 1)
+		kstat.per_cpu_system[cpu] += system;
+}
+
+/*
+ * Nr of active tasks - counted in fixed-point numbers
+ */
+static unsigned long count_active_tasks(void)
+{
+	struct task_struct *p;
+	unsigned long nr = 0;
+
+	read_lock(&tasklist_lock);
+	for_each_task(p) {
+		if ((p->state == TASK_RUNNING ||
+		     (p->state & TASK_UNINTERRUPTIBLE)))
+			nr += FIXED_1;
+	}
+	read_unlock(&tasklist_lock);
+	return nr;
+}
+
+/*
+ * 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];
+
+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);
+	}
+}
+
+/* jiffies at the most recent update of wall time */
+unsigned long wall_jiffies;
+
+/*
+ * This spinlock protect us from races in SMP while playing with xtime. -arca
+ */
+rwlock_t xtime_lock = RW_LOCK_UNLOCKED;
+
+static inline void update_times(void)
+{
+	unsigned long ticks;
+
+	/*
+	 * update_times() is run from the raw timer_bh handler so we
+	 * just know that the irqs are locally enabled and so we don't
+	 * need to save/restore the flags of the local CPU here. -arca
+	 */
+	write_lock_irq(&xtime_lock);
+	vxtime_lock();
+
+	ticks = jiffies - wall_jiffies;
+	if (ticks) {
+		wall_jiffies += ticks;
+		update_wall_time(ticks);
+	}
+	vxtime_unlock();
+	write_unlock_irq(&xtime_lock);
+	calc_load(ticks);
+}
+
+void timer_bh(void)
+{
+	update_times();
+	run_timer_list();
+}
+
+void do_timer(struct pt_regs *regs)
+{
+	(*(unsigned long *)&jiffies)++;
+#ifndef CONFIG_SMP
+	/* SMP process accounting uses the local APIC timer */
+
+	update_process_times(user_mode(regs));
+#endif
+	mark_bh(TIMER_BH);
+	if (TQ_ACTIVE(tq_timer))
+		mark_bh(TQUEUE_BH);
+}
+
+#if !defined(__alpha__) && !defined(__ia64__)
+
+/*
+ * For backwards compatibility?  This can be done in libc so Alpha
+ * and all newer ports shouldn't need it.
+ */
+asmlinkage unsigned long 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;
+	do_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;
+}
+
+#endif
+
+#ifndef __alpha__
+
+/*
+ * The Alpha uses getxpid, getxuid, and getxgid instead.  Maybe this
+ * should be moved into arch/i386 instead?
+ */
+
+/**
+ * sys_getpid - return the thread group id of the current process
+ *
+ * Note, despite the name, this returns the tgid not the pid.  The tgid and
+ * the pid are identical unless CLONE_THREAD was specified on clone() in
+ * which case the tgid is the same in all threads of the same group.
+ *
+ * This is SMP safe as current->tgid does not change.
+ */
+asmlinkage long sys_getpid(void)
+{
+	return current->tgid;
+}
+
+/*
+ * This is not strictly SMP safe: p_opptr could change
+ * from under us. However, rather than getting any lock
+ * we can use an optimistic algorithm: get the parent
+ * pid, and go back and check that the parent is still
+ * the same. If it has changed (which is extremely unlikely
+ * indeed), we just try again..
+ *
+ * NOTE! This depends on the fact that even if we _do_
+ * get an old value of "parent", we can happily dereference
+ * the pointer: we just can't necessarily trust the result
+ * until we know that the parent pointer is valid.
+ *
+ * The "mb()" macro is a memory barrier - a synchronizing
+ * event. It also makes sure that gcc doesn't optimize
+ * away the necessary memory references.. The barrier doesn't
+ * have to have all that strong semantics: on x86 we don't
+ * really require a synchronizing instruction, for example.
+ * The barrier is more important for code generation than
+ * for any real memory ordering semantics (even if there is
+ * a small window for a race, using the old pointer is
+ * harmless for a while).
+ */
+asmlinkage long sys_getppid(void)
+{
+	int pid;
+	struct task_struct * me = current;
+	struct task_struct * parent;
+
+	parent = me->p_opptr;
+	for (;;) {
+		pid = parent->pid;
+#if CONFIG_SMP
+{
+		struct task_struct *old = parent;
+		mb();
+		parent = me->p_opptr;
+		if (old != parent)
+			continue;
+}
+#endif
+		break;
+	}
+	return pid;
+}
+
+asmlinkage long sys_getuid(void)
+{
+	/* Only we change this so SMP safe */
+	return current->uid;
+}
+
+asmlinkage long sys_geteuid(void)
+{
+	/* Only we change this so SMP safe */
+	return current->euid;
+}
+
+asmlinkage long sys_getgid(void)
+{
+	/* Only we change this so SMP safe */
+	return current->gid;
+}
+
+asmlinkage long sys_getegid(void)
+{
+	/* Only we change this so SMP safe */
+	return  current->egid;
+}
+
+#endif
+
+/* Thread ID - the internal kernel "pid" */
+asmlinkage long sys_gettid(void)
+{
+	return current->pid;
+}
+
+asmlinkage long sys_nanosleep(struct timespec *rqtp, struct timespec *rmtp)
+{
+	struct timespec t;
+	unsigned long expire;
+
+	if(copy_from_user(&t, rqtp, sizeof(struct timespec)))
+		return -EFAULT;
+
+	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.
+		 *
+		 * Its important on SMP not to do this holding locks.
+		 */
+		udelay((t.tv_nsec + 999) / 1000);
+		return 0;
+	}
+
+	expire = timespec_to_jiffies(&t) + (t.tv_sec || t.tv_nsec);
+
+	current->state = TASK_INTERRUPTIBLE;
+	expire = schedule_timeout(expire);
+
+	if (expire) {
+		if (rmtp) {
+			jiffies_to_timespec(expire, &t);
+			if (copy_to_user(rmtp, &t, sizeof(struct timespec)))
+				return -EFAULT;
+		}
+		return -EINTR;
+	}
+	return 0;
+}
+