5 files changed, 25 insertions, 19 deletions

diff --git a/include/linux/time.h b/include/linux/time.h
index 2091a19f1655..d32ef0ad4c0a 100644
--- a/include/linux/time.h
+++ b/include/linux/time.h
@@ -174,6 +174,10 @@ static inline void timespec_add_ns(struct timespec *a, u64 ns)
 {
         ns += a->tv_nsec;
         while(unlikely(ns >= NSEC_PER_SEC)) {
+                /* The following asm() prevents the compiler from
+                 * optimising this loop into a modulo operation.  */
+                asm("" : "+r"(ns));
+
                 ns -= NSEC_PER_SEC;
                 a->tv_sec++;
         }
diff --git a/include/linux/timex.h b/include/linux/timex.h
index c3f374786a43..8ea3e71ba7fa 100644
--- a/include/linux/timex.h
+++ b/include/linux/timex.h
@@ -232,14 +232,7 @@ static inline int ntp_synced(void)
 #else
 #define NTP_INTERVAL_FREQ  (HZ)
 #endif
-
-#define CLOCK_TICK_OVERFLOW     (LATCH * HZ - CLOCK_TICK_RATE)
-#define CLOCK_TICK_ADJUST       (((s64)CLOCK_TICK_OVERFLOW * NSEC_PER_SEC) / \
-                                        (s64)CLOCK_TICK_RATE)
-
-/* Because using NSEC_PER_SEC would be too easy */
-#define NTP_INTERVAL_LENGTH ((((s64)TICK_USEC * NSEC_PER_USEC * USER_HZ) + \
-                              CLOCK_TICK_ADJUST) / NTP_INTERVAL_FREQ)
+#define NTP_INTERVAL_LENGTH (NSEC_PER_SEC/NTP_INTERVAL_FREQ)
 
 /* Returns how long ticks are at present, in ns / 2^(SHIFT_SCALE-10). */
 extern u64 current_tick_length(void);
diff --git a/kernel/time/ntp.c b/kernel/time/ntp.c
index c88b5910e7ab..5fd9b9469770 100644
--- a/kernel/time/ntp.c
+++ b/kernel/time/ntp.c
@@ -42,12 +42,13 @@ long time_esterror = NTP_PHASE_LIMIT;	/* estimated error (us)		*/
 long time_freq;                         /* frequency offset (scaled ppm)*/
 static long time_reftime;               /* time at last adjustment (s)  */
 long time_adjust;
+static long ntp_tick_adj;
 
 static void ntp_update_frequency(void)
 {
         u64 second_length = (u64)(tick_usec * NSEC_PER_USEC * USER_HZ)
                                 << TICK_LENGTH_SHIFT;
-        second_length += (s64)CLOCK_TICK_ADJUST << TICK_LENGTH_SHIFT;
+        second_length += (s64)ntp_tick_adj << TICK_LENGTH_SHIFT;
         second_length += (s64)time_freq << (TICK_LENGTH_SHIFT - SHIFT_NSEC);
 
         tick_length_base = second_length;
@@ -342,14 +343,16 @@ int do_adjtimex(struct timex *txc)
                     freq_adj = shift_right(freq_adj, time_constant * 2 +
                                            (SHIFT_PLL + 2) * 2 - SHIFT_NSEC);
                     if (mtemp >= MINSEC && (time_status & STA_FLL || mtemp > MAXSEC)) {
+                        u64 utemp64;
                         temp64 = time_offset << (SHIFT_NSEC - SHIFT_FLL);
                         if (time_offset < 0) {
-                            temp64 = -temp64;
-                            do_div(temp64, mtemp);
-                            freq_adj -= temp64;
+                            utemp64 = -temp64;
+                            do_div(utemp64, mtemp);
+                            freq_adj -= utemp64;
                         } else {
-                            do_div(temp64, mtemp);
-                            freq_adj += temp64;
+                            utemp64 = temp64;
+                            do_div(utemp64, mtemp);
+                            freq_adj += utemp64;
                         }
                     }
                     freq_adj += time_freq;
@@ -400,3 +403,11 @@ leave:	if ((time_status & (STA_UNSYNC|STA_CLOCKERR)) != 0)
         notify_cmos_timer();
         return(result);
 }
+
+static int __init ntp_tick_adj_setup(char *str)
+{
+        ntp_tick_adj = simple_strtol(str, NULL, 0);
+        return 1;
+}
+
+__setup("ntp_tick_adj=", ntp_tick_adj_setup);
diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c
index 2968298f8f36..686da821d376 100644
--- a/kernel/time/tick-sched.c
+++ b/kernel/time/tick-sched.c
@@ -640,7 +640,7 @@ void tick_cancel_sched_timer(int cpu)
 
         if (ts->sched_timer.base)
                 hrtimer_cancel(&ts->sched_timer);
-        ts->tick_stopped = 0;
+
         ts->nohz_mode = NOHZ_MODE_INACTIVE;
 }
 #endif /* HIGH_RES_TIMERS */
diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c
index 1af9fb050fe2..671af612b768 100644
--- a/kernel/time/timekeeping.c
+++ b/kernel/time/timekeeping.c
@@ -187,8 +187,7 @@ static void change_clocksource(void)
 
         clock->error = 0;
         clock->xtime_nsec = 0;
-        clocksource_calculate_interval(clock,
-                (unsigned long)(current_tick_length()>>TICK_LENGTH_SHIFT));
+        clocksource_calculate_interval(clock, NTP_INTERVAL_LENGTH);
 
         tick_clock_notify();
 
@@ -245,8 +244,7 @@ void __init timekeeping_init(void)
         ntp_clear();
 
         clock = clocksource_get_next();
-        clocksource_calculate_interval(clock,
-                (unsigned long)(current_tick_length()>>TICK_LENGTH_SHIFT));
+        clocksource_calculate_interval(clock, NTP_INTERVAL_LENGTH);
         clock->cycle_last = clocksource_read(clock);
 
         xtime.tv_sec = sec;