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>

diff --git a/include/linux/timekeeping.h b/include/linux/timekeeping.h
index 1caa6b04fdc5ce09a0c27b4951ba03b200182940..071ad7e0c981a13d6b7d23eafc31ab3a84ad5458 100644 (file)
--- 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;

diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c
index 41fcbe19ccfe4443805ea4a73162cab5044c5021..10140dae71c69537d7093fe65c6a91b2012cb021 100644 (file)
--- a/kernel/time/timekeeping.c
+++ b/kernel/time/timekeeping.c
@@ -703,18 +703,18 @@ void do_gettimeofday(struct timeval *tv)
 EXPORT_SYMBOL(do_gettimeofday);
 
 /**
- * do_settimeofday - Sets the time of day
- * @tv:                pointer to the timespec variable containing the new time
+ * do_settimeofday64 - Sets the time of day.
+ * @ts:     pointer to the timespec64 variable containing the new time
  *
  * Sets the time of day to the new time and update NTP and notify hrtimers
  */
-int do_settimeofday(const struct timespec *tv)
+int do_settimeofday64(const struct timespec64 *ts)
 {
        struct timekeeper *tk = &tk_core.timekeeper;
-       struct timespec64 ts_delta, xt, tmp;
+       struct timespec64 ts_delta, xt;
        unsigned long flags;
 
-       if (!timespec_valid_strict(tv))
+       if (!timespec64_valid_strict(ts))
                return -EINVAL;
 
        raw_spin_lock_irqsave(&timekeeper_lock, flags);
@@ -723,13 +723,12 @@ int do_settimeofday(const struct timespec *tv)
        timekeeping_forward_now(tk);
 
        xt = tk_xtime(tk);
-       ts_delta.tv_sec = tv->tv_sec - xt.tv_sec;
-       ts_delta.tv_nsec = tv->tv_nsec - xt.tv_nsec;
+       ts_delta.tv_sec = ts->tv_sec - xt.tv_sec;
+       ts_delta.tv_nsec = ts->tv_nsec - xt.tv_nsec;
 
        tk_set_wall_to_mono(tk, timespec64_sub(tk->wall_to_monotonic, ts_delta));
 
-       tmp = timespec_to_timespec64(*tv);
-       tk_set_xtime(tk, &tmp);
+       tk_set_xtime(tk, ts);
 
        timekeeping_update(tk, TK_CLEAR_NTP | TK_MIRROR | TK_CLOCK_WAS_SET);
 
@@ -741,7 +740,7 @@ int do_settimeofday(const struct timespec *tv)
 
        return 0;
 }
-EXPORT_SYMBOL(do_settimeofday);
+EXPORT_SYMBOL(do_settimeofday64);
 
 /**
  * timekeeping_inject_offset - Adds or subtracts from the current time.