[PATCH 03/21] time: Add y2038 safe update_persistent_clock64()

John Stultz
2015-04-02T03:39:30Z

From: Xunlei Pang <pang.xunlei@linaro.org>

As part of addressing in-kernel y2038 issues, this patch adds
update_persistent_clock64() and replaces all the call sites of
update_persistent_clock() with this function. This is a __weak
implementation, which simply calls the existing y2038 unsafe
update_persistent_clock().

This allows architecture specific implementations to be converted
independently, and eventually y2038-unsafe update_persistent_clock()
can be removed after all its architecture specific implementations
have been converted to update_persistent_clock64().

Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@kernel.org>
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>
---
drivers/rtc/systohc.c | 2 +-
include/linux/timekeeping.h | 1 +
kernel/time/ntp.c | 13 ++++++++++++-
3 files changed, 14 insertions(+), 2 deletions(-)

diff --git a/drivers/rtc/systohc.c b/drivers/rtc/systohc.c
index eb71872..ef3c07a 100644
--- a/drivers/rtc/systohc.c
+++ b/drivers/rtc/systohc.c
@@ -11,7 +11,7 @@
* rtc_set_ntp_time - Save NTP synchronized time to the RTC
* @now: Current time of day
*
- * Replacement for the NTP platform function update_persistent_clock
+ * Replacement for the NTP platform function update_persistent_clock64
* that stores time for later retrieval by rtc_hctosys.
*
* Returns 0 on successful RTC update, -ENODEV if a RTC update is not
diff --git a/include/linux/timekeeping.h b/include/linux/timekeeping.h
index 4c0f76f..7a2369d 100644
--- a/include/linux/timekeeping.h
+++ b/include/linux/timekeeping.h
@@ -272,6 +272,7 @@ extern void read_persistent_clock64(struct timespec64 *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);
+extern int update_persistent_clock64(struct timespec64 now);

#endif
diff --git a/kernel/time/ntp.c b/kernel/time/ntp.c
index 0f60b08..42d1bc7 100644
--- a/kernel/time/ntp.c
+++ b/kernel/time/ntp.c
@@ -459,6 +459,16 @@ out:
return leap;
}

+#ifdef CONFIG_GENERIC_CMOS_UPDATE
+int __weak update_persistent_clock64(struct timespec64 now64)
+{
+ struct timespec now;
+
+ now = timespec64_to_timespec(now64);
+ return update_persistent_clock(now);
+}
+#endif
+
#if defined(CONFIG_GENERIC_CMOS_UPDATE) || defined(CONFIG_RTC_SYSTOHC)
static void sync_cmos_clock(struct work_struct *work);

@@ -494,8 +504,9 @@ static void sync_cmos_clock(struct work_struct *work)
if (persistent_clock_is_local)
adjust.tv_sec -= (sys_tz.tz_minuteswest * 60);
#ifdef CONFIG_GENERIC_CMOS_UPDATE
- fail = update_persistent_clock(timespec64_to_timespec(adjust));
+ fail = update_persistent_clock64(adjust);
#endif
+
#ifdef CONFIG_RTC_SYSTOHC
if (fail == -ENODEV)
fail = rtc_set_ntp_time(adjust);
--
1.9.1