diff --git a/arch/um/os-Linux/time.c b/arch/um/os-Linux/time.c
index cf30a39..6f76267 100644
--- a/arch/um/os-Linux/time.c
+++ b/arch/um/os-Linux/time.c
@@ -1,21 +1,128 @@
-#include <stdlib.h>
-#include <sys/time.h>
+/*
+ * Copyright (C) 2000, 2001, 2002 Jeff Dike (jdike@karaya.com)
+ * Licensed under the GPL
+ */
 
-unsigned long long os_usecs(void)
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <time.h>
+#include <sys/time.h>
+#include <signal.h>
+#include <errno.h>
+#include "user_util.h"
+#include "kern_util.h"
+#include "user.h"
+#include "process.h"
+#include "kern_constants.h"
+#include "os.h"
+
+/* XXX This really needs to be declared and initialized in a kernel file since
+ * it's in <linux/time.h>
+ */
+extern struct timespec wall_to_monotonic;
+
+static void set_interval(int timer_type)
+{
+	int usec = 1000000/hz();
+	struct itimerval interval = ((struct itimerval) { { 0, usec },
+							  { 0, usec } });
+
+	if(setitimer(timer_type, &interval, NULL) == -1)
+		panic("setitimer failed - errno = %d\n", errno);
+}
+
+void enable_timer(void)
+{
+	set_interval(ITIMER_VIRTUAL);
+}
+
+void disable_timer(void)
+{
+	struct itimerval disable = ((struct itimerval) { { 0, 0 }, { 0, 0 }});
+	if((setitimer(ITIMER_VIRTUAL, &disable, NULL) < 0) ||
+	   (setitimer(ITIMER_REAL, &disable, NULL) < 0))
+		printk("disnable_timer - setitimer failed, errno = %d\n",
+		       errno);
+	/* If there are signals already queued, after unblocking ignore them */
+	set_handler(SIGALRM, SIG_IGN, 0, -1);
+	set_handler(SIGVTALRM, SIG_IGN, 0, -1);
+}
+
+void switch_timers(int to_real)
+{
+	struct itimerval disable = ((struct itimerval) { { 0, 0 }, { 0, 0 }});
+	struct itimerval enable = ((struct itimerval) { { 0, 1000000/hz() },
+							{ 0, 1000000/hz() }});
+	int old, new;
+
+	if(to_real){
+		old = ITIMER_VIRTUAL;
+		new = ITIMER_REAL;
+	}
+	else {
+		old = ITIMER_REAL;
+		new = ITIMER_VIRTUAL;
+	}
+
+	if((setitimer(old, &disable, NULL) < 0) ||
+	   (setitimer(new, &enable, NULL)))
+		printk("switch_timers - setitimer failed, errno = %d\n",
+		       errno);
+}
+
+void uml_idle_timer(void)
+{
+	if(signal(SIGVTALRM, SIG_IGN) == SIG_ERR)
+		panic("Couldn't unset SIGVTALRM handler");
+
+	set_handler(SIGALRM, (__sighandler_t) alarm_handler,
+		    SA_RESTART, SIGUSR1, SIGIO, SIGWINCH, SIGVTALRM, -1);
+	set_interval(ITIMER_REAL);
+}
+
+extern void ktime_get_ts(struct timespec *ts);
+#define do_posix_clock_monotonic_gettime(ts) ktime_get_ts(ts)
+
+void time_init(void)
+{
+	struct timespec now;
+
+	if(signal(SIGVTALRM, boot_timer_handler) == SIG_ERR)
+		panic("Couldn't set SIGVTALRM handler");
+	set_interval(ITIMER_VIRTUAL);
+
+	do_posix_clock_monotonic_gettime(&now);
+	wall_to_monotonic.tv_sec = -now.tv_sec;
+	wall_to_monotonic.tv_nsec = -now.tv_nsec;
+}
+
+unsigned long long os_nsecs(void)
 {
 	struct timeval tv;
 
 	gettimeofday(&tv, NULL);
-	return((unsigned long long) tv.tv_sec * 1000000 + tv.tv_usec);
+	return((unsigned long long) tv.tv_sec * BILLION + tv.tv_usec * 1000);
 }
 
-/*
- * Overrides for Emacs so that we follow Linus's tabbing style.
- * Emacs will notice this stuff at the end of the file and automatically
- * adjust the settings for this buffer only.  This must remain at the end
- * of the file.
- * ---------------------------------------------------------------------------
- * Local variables:
- * c-file-style: "linux"
- * End:
- */
+void idle_sleep(int secs)
+{
+	struct timespec ts;
+
+	ts.tv_sec = secs;
+	ts.tv_nsec = 0;
+	nanosleep(&ts, NULL);
+}
+
+/* XXX This partly duplicates init_irq_signals */
+
+void user_time_init(void)
+{
+	set_handler(SIGVTALRM, (__sighandler_t) alarm_handler,
+		    SA_ONSTACK | SA_RESTART, SIGUSR1, SIGIO, SIGWINCH,
+		    SIGALRM, SIGUSR2, -1);
+	set_handler(SIGALRM, (__sighandler_t) alarm_handler,
+		    SA_ONSTACK | SA_RESTART, SIGUSR1, SIGIO, SIGWINCH,
+		    SIGVTALRM, SIGUSR2, -1);
+	set_interval(ITIMER_VIRTUAL);
+}