time: Add y2038 safe read_boot_clock64()

As part of addressing in-kernel y2038 issues, this patch adds
read_boot_clock64() and replaces all the call sites of
read_boot_clock() with this function. This is a __weak
implementation, which simply calls the existing y2038 unsafe
read_boot_clock().

This allows architecture specific implementations to be
converted independently, and eventually the y2038 unsafe
read_boot_clock() can be removed after all its architecture
specific implementations have been converted to
read_boot_clock64().

Suggested-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Xunlei Pang <pang.xunlei@linaro.org>
Signed-off-by: John Stultz <john.stultz@linaro.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1427945681-29972-2-git-send-email-john.stultz@linaro.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>

diff --git a/include/linux/timekeeping.h b/include/linux/timekeeping.h
index 5047b83483d6675f5309dfbb04eb33c3d67ba9bc..18d27a3f72ca00b357d90f43ba94d993760a551f 100644 (file)
--- a/include/linux/timekeeping.h
+++ b/include/linux/timekeeping.h
@@ -269,6 +269,7 @@ static inline bool has_persistent_clock(void)
 
 extern void read_persistent_clock(struct timespec *ts);
 extern void read_boot_clock(struct timespec *ts);
+extern void read_boot_clock64(struct timespec64 *ts);
 extern int update_persistent_clock(struct timespec now);
 
 

diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c
index 5b12292b343ad20067c0431bba8b4a3c6c5514e7..652e50a9c6ed4d4448b93bacca38ba1756fc6e9f 100644 (file)
--- a/kernel/time/timekeeping.c
+++ b/kernel/time/timekeeping.c
@@ -1188,6 +1188,14 @@ void __weak read_boot_clock(struct timespec *ts)
        ts->tv_nsec = 0;
 }
 
+void __weak read_boot_clock64(struct timespec64 *ts64)
+{
+       struct timespec ts;
+
+       read_boot_clock(&ts);
+       *ts64 = timespec_to_timespec64(ts);
+}
+
 /*
  * timekeeping_init - Initializes the clocksource and common timekeeping values
  */
@@ -1209,8 +1217,7 @@ void __init timekeeping_init(void)
        } else if (now.tv_sec || now.tv_nsec)
                persistent_clock_exist = true;
 
-       read_boot_clock(&ts);
-       boot = timespec_to_timespec64(ts);
+       read_boot_clock64(&boot);
        if (!timespec64_valid_strict(&boot)) {
                pr_warn("WARNING: Boot clock returned invalid value!\n"
                        "         Check your CMOS/BIOS settings.\n");