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-rw-r--r--include/linux/time.h2
-rw-r--r--kernel/time/timekeeping.c37
2 files changed, 39 insertions, 0 deletions
diff --git a/include/linux/time.h b/include/linux/time.h
index dda9be6..4bb05a8 100644
--- a/include/linux/time.h
+++ b/include/linux/time.h
@@ -116,6 +116,8 @@ extern int do_setitimer(int which, struct itimerval *value,
extern unsigned int alarm_setitimer(unsigned int seconds);
extern int do_getitimer(int which, struct itimerval *value);
extern void getnstimeofday(struct timespec *tv);
+extern void getboottime(struct timespec *ts);
+extern void monotonic_to_bootbased(struct timespec *ts);
extern struct timespec timespec_trunc(struct timespec t, unsigned gran);
extern int timekeeping_is_continuous(void);
diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c
index 3d1042f..728cedf 100644
--- a/kernel/time/timekeeping.c
+++ b/kernel/time/timekeeping.c
@@ -36,9 +36,17 @@ EXPORT_SYMBOL(xtime_lock);
* at zero at system boot time, so wall_to_monotonic will be negative,
* however, we will ALWAYS keep the tv_nsec part positive so we can use
* the usual normalization.
+ *
+ * wall_to_monotonic is moved after resume from suspend for the monotonic
+ * time not to jump. We need to add total_sleep_time to wall_to_monotonic
+ * to get the real boot based time offset.
+ *
+ * - wall_to_monotonic is no longer the boot time, getboottime must be
+ * used instead.
*/
struct timespec xtime __attribute__ ((aligned (16)));
struct timespec wall_to_monotonic __attribute__ ((aligned (16)));
+static unsigned long total_sleep_time; /* seconds */
EXPORT_SYMBOL(xtime);
@@ -251,6 +259,7 @@ void __init timekeeping_init(void)
xtime.tv_nsec = 0;
set_normalized_timespec(&wall_to_monotonic,
-xtime.tv_sec, -xtime.tv_nsec);
+ total_sleep_time = 0;
write_sequnlock_irqrestore(&xtime_lock, flags);
}
@@ -282,6 +291,7 @@ static int timekeeping_resume(struct sys_device *dev)
xtime.tv_sec += sleep_length;
wall_to_monotonic.tv_sec -= sleep_length;
+ total_sleep_time += sleep_length;
}
/* re-base the last cycle value */
clock->cycle_last = clocksource_read(clock);
@@ -476,3 +486,30 @@ void update_wall_time(void)
change_clocksource();
update_vsyscall(&xtime, clock);
}
+
+/**
+ * getboottime - Return the real time of system boot.
+ * @ts: pointer to the timespec to be set
+ *
+ * Returns the time of day in a timespec.
+ *
+ * This is based on the wall_to_monotonic offset and the total suspend
+ * time. Calls to settimeofday will affect the value returned (which
+ * basically means that however wrong your real time clock is at boot time,
+ * you get the right time here).
+ */
+void getboottime(struct timespec *ts)
+{
+ set_normalized_timespec(ts,
+ - (wall_to_monotonic.tv_sec + total_sleep_time),
+ - wall_to_monotonic.tv_nsec);
+}
+
+/**
+ * monotonic_to_bootbased - Convert the monotonic time to boot based.
+ * @ts: pointer to the timespec to be converted
+ */
+void monotonic_to_bootbased(struct timespec *ts)
+{
+ ts->tv_sec += total_sleep_time;
+}
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