time: Provide y2038 safe do_settimeofday() replacement

The kernel uses 32-bit signed value(time_t) for seconds elapsed
1970-01-01:00:00:00, thus it will overflow at 2038-01-19 03:14:08
on 32-bit systems. This is widely known as the y2038 problem.

As part of addressing "y2038 problem" for in-kernel uses, this patch
adds safe do_settimeofday64() using timespec64.

After this patch, do_settimeofday() is deprecated and all its call
sites will be fixed using do_settimeofday64(), after that it can be
removed.

Signed-off-by: pang.xunlei <pang.xunlei@linaro.org>
Signed-off-by: John Stultz <john.stultz@linaro.org>

1 files changed, 20 insertions, 1 deletions

diff --git a/include/linux/timekeeping.h b/include/linux/timekeeping.h
index 1caa6b04fdc5..071ad7e0c981 100644
--- a/include/linux/timekeeping.h
+++ b/include/linux/timekeeping.h
@@ -10,7 +10,7 @@ extern int timekeeping_suspended;
  * Get and set timeofday
  */
 extern void do_gettimeofday(struct timeval *tv);
-extern int do_settimeofday(const struct timespec *tv);
+extern int do_settimeofday64(const struct timespec64 *ts);
 extern int do_sys_settimeofday(const struct timespec *tv,
 			       const struct timezone *tz);
 
@@ -33,6 +33,14 @@ extern int __getnstimeofday64(struct timespec64 *tv);
 extern void getnstimeofday64(struct timespec64 *tv);
 
 #if BITS_PER_LONG == 64
+/**
+ * Deprecated. Use do_settimeofday64().
+ */
+static inline int do_settimeofday(const struct timespec *ts)
+{
+	return do_settimeofday64(ts);
+}
+
 static inline int __getnstimeofday(struct timespec *ts)
 {
 	return __getnstimeofday64(ts);
@@ -54,6 +62,17 @@ static inline void ktime_get_real_ts(struct timespec *ts)
 }
 
 #else
+/**
+ * Deprecated. Use do_settimeofday64().
+ */
+static inline int do_settimeofday(const struct timespec *ts)
+{
+	struct timespec64 ts64;
+
+	ts64 = timespec_to_timespec64(*ts);
+	return do_settimeofday64(&ts64);
+}
+
 static inline int __getnstimeofday(struct timespec *ts)
 {
 	struct timespec64 ts64;