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-rw-r--r--kernel/time/ntp.c129
1 files changed, 81 insertions, 48 deletions
diff --git a/kernel/time/ntp.c b/kernel/time/ntp.c
index e1fa3689a903..3479ec48e604 100644
--- a/kernel/time/ntp.c
+++ b/kernel/time/ntp.c
@@ -1,53 +1,81 @@
/*
- * linux/kernel/time/ntp.c
- *
* NTP state machine interfaces and logic.
*
* This code was mainly moved from kernel/timer.c and kernel/time.c
* Please see those files for relevant copyright info and historical
* changelogs.
*/
-
-#include <linux/mm.h>
-#include <linux/time.h>
-#include <linux/timex.h>
-#include <linux/jiffies.h>
-#include <linux/hrtimer.h>
#include <linux/capability.h>
-#include <linux/math64.h>
#include <linux/clocksource.h>
#include <linux/workqueue.h>
-#include <asm/timex.h>
+#include <linux/hrtimer.h>
+#include <linux/jiffies.h>
+#include <linux/math64.h>
+#include <linux/timex.h>
+#include <linux/time.h>
+#include <linux/mm.h>
/*
- * Timekeeping variables
+ * NTP timekeeping variables:
*/
-unsigned long tick_usec = TICK_USEC; /* USER_HZ period (usec) */
-unsigned long tick_nsec; /* ACTHZ period (nsec) */
-u64 tick_length;
-static u64 tick_length_base;
-static struct hrtimer leap_timer;
+/* USER_HZ period (usecs): */
+unsigned long tick_usec = TICK_USEC;
+
+/* ACTHZ period (nsecs): */
+unsigned long tick_nsec;
-#define MAX_TICKADJ 500 /* microsecs */
-#define MAX_TICKADJ_SCALED (((u64)(MAX_TICKADJ * NSEC_PER_USEC) << \
- NTP_SCALE_SHIFT) / NTP_INTERVAL_FREQ)
+u64 tick_length;
+static u64 tick_length_base;
+
+static struct hrtimer leap_timer;
+
+#define MAX_TICKADJ 500 /* usecs */
+#define MAX_TICKADJ_SCALED \
+ (((u64)(MAX_TICKADJ * NSEC_PER_USEC) << NTP_SCALE_SHIFT) / NTP_INTERVAL_FREQ)
/*
* phase-lock loop variables
*/
-/* TIME_ERROR prevents overwriting the CMOS clock */
-static int time_state = TIME_OK; /* clock synchronization status */
-int time_status = STA_UNSYNC; /* clock status bits */
-static long time_tai; /* TAI offset (s) */
-static s64 time_offset; /* time adjustment (ns) */
-static long time_constant = 2; /* pll time constant */
-long time_maxerror = NTP_PHASE_LIMIT; /* maximum error (us) */
-long time_esterror = NTP_PHASE_LIMIT; /* estimated error (us) */
-static s64 time_freq; /* frequency offset (scaled ns/s)*/
-static long time_reftime; /* time at last adjustment (s) */
-long time_adjust;
-static long ntp_tick_adj;
+
+/*
+ * clock synchronization status
+ *
+ * (TIME_ERROR prevents overwriting the CMOS clock)
+ */
+static int time_state = TIME_OK;
+
+/* clock status bits: */
+int time_status = STA_UNSYNC;
+
+/* TAI offset (secs): */
+static long time_tai;
+
+/* time adjustment (nsecs): */
+static s64 time_offset;
+
+/* pll time constant: */
+static long time_constant = 2;
+
+/* maximum error (usecs): */
+long time_maxerror = NTP_PHASE_LIMIT;
+
+/* estimated error (usecs): */
+long time_esterror = NTP_PHASE_LIMIT;
+
+/* frequency offset (scaled nsecs/secs): */
+static s64 time_freq;
+
+/* time at last adjustment (secs): */
+static long time_reftime;
+
+long time_adjust;
+
+static long ntp_tick_adj;
+
+/*
+ * NTP methods:
+ */
static void ntp_update_frequency(void)
{
@@ -118,15 +146,15 @@ static void ntp_update_offset(long offset)
*/
void ntp_clear(void)
{
- time_adjust = 0; /* stop active adjtime() */
- time_status |= STA_UNSYNC;
- time_maxerror = NTP_PHASE_LIMIT;
- time_esterror = NTP_PHASE_LIMIT;
+ time_adjust = 0; /* stop active adjtime() */
+ time_status |= STA_UNSYNC;
+ time_maxerror = NTP_PHASE_LIMIT;
+ time_esterror = NTP_PHASE_LIMIT;
ntp_update_frequency();
- tick_length = tick_length_base;
- time_offset = 0;
+ tick_length = tick_length_base;
+ time_offset = 0;
}
/*
@@ -147,8 +175,8 @@ static enum hrtimer_restart ntp_leap_second(struct hrtimer *timer)
xtime.tv_sec--;
wall_to_monotonic.tv_sec++;
time_state = TIME_OOP;
- printk(KERN_NOTICE "Clock: "
- "inserting leap second 23:59:60 UTC\n");
+ printk(KERN_NOTICE
+ "Clock: inserting leap second 23:59:60 UTC\n");
hrtimer_add_expires_ns(&leap_timer, NSEC_PER_SEC);
res = HRTIMER_RESTART;
break;
@@ -157,8 +185,8 @@ static enum hrtimer_restart ntp_leap_second(struct hrtimer *timer)
time_tai--;
wall_to_monotonic.tv_sec--;
time_state = TIME_WAIT;
- printk(KERN_NOTICE "Clock: "
- "deleting leap second 23:59:59 UTC\n");
+ printk(KERN_NOTICE
+ "Clock: deleting leap second 23:59:59 UTC\n");
break;
case TIME_OOP:
time_tai++;
@@ -199,10 +227,10 @@ void second_overflow(void)
* Compute the phase adjustment for the next second. The offset is
* reduced by a fixed factor times the time constant.
*/
- tick_length = tick_length_base;
- time_adj = shift_right(time_offset, SHIFT_PLL + time_constant);
- time_offset -= time_adj;
- tick_length += time_adj;
+ tick_length = tick_length_base;
+ time_adj = shift_right(time_offset, SHIFT_PLL + time_constant);
+ time_offset -= time_adj;
+ tick_length += time_adj;
if (unlikely(time_adjust)) {
if (time_adjust > MAX_TICKADJ) {
@@ -240,12 +268,13 @@ static void sync_cmos_clock(struct work_struct *work)
* This code is run on a timer. If the clock is set, that timer
* may not expire at the correct time. Thus, we adjust...
*/
- if (!ntp_synced())
+ if (!ntp_synced()) {
/*
* Not synced, exit, do not restart a timer (if one is
* running, let it run out).
*/
return;
+ }
getnstimeofday(&now);
if (abs(now.tv_nsec - (NSEC_PER_SEC / 2)) <= tick_nsec / 2)
@@ -277,7 +306,8 @@ static void notify_cmos_timer(void)
static inline void notify_cmos_timer(void) { }
#endif
-/* adjtimex mainly allows reading (and writing, if superuser) of
+/*
+ * adjtimex mainly allows reading (and writing, if superuser) of
* kernel time-keeping variables. used by xntpd.
*/
int do_adjtimex(struct timex *txc)
@@ -298,7 +328,10 @@ int do_adjtimex(struct timex *txc)
if (txc->modes && !capable(CAP_SYS_TIME))
return -EPERM;
- /* if the quartz is off by more than 10% something is VERY wrong! */
+ /*
+ * if the quartz is off by more than 10% then
+ * something is VERY wrong!
+ */
if (txc->modes & ADJ_TICK &&
(txc->tick < 900000/USER_HZ ||
txc->tick > 1100000/USER_HZ))