time: Add y2038 safe read_persistent_clock64()

As part of addressing in-kernel y2038 issues, this patch adds
read_persistent_clock64() and replaces all the call sites of
read_persistent_clock() with this function. This is a __weak
implementation, which simply calls the existing y2038 unsafe
read_persistent_clock().

This allows architecture specific implementations to be
converted independently, and eventually the y2038 unsafe
read_persistent_clock() can be removed after all its
architecture specific implementations have been converted to
read_persistent_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/1427945681-29972-3-git-send-email-john.stultz@linaro.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>

diff --git a/arch/mips/lasat/sysctl.c b/arch/mips/lasat/sysctl.c
index 3b7f65cc42187e95627bdd14b461be0e60e7342b..cf9b4633257eb86dd14cea3656b94104ce8d909a 100644 (file)
--- a/arch/mips/lasat/sysctl.c
+++ b/arch/mips/lasat/sysctl.c
@@ -75,11 +75,11 @@ static int rtctmp;
 int proc_dolasatrtc(struct ctl_table *table, int write,
                       void *buffer, size_t *lenp, loff_t *ppos)
 {
-       struct timespec ts;
+       struct timespec64 ts;
        int r;
 
        if (!write) {
-               read_persistent_clock(&ts);
+               read_persistent_clock64(&ts);
                rtctmp = ts.tv_sec;
                /* check for time < 0 and set to 0 */
                if (rtctmp < 0)

diff --git a/include/linux/timekeeping.h b/include/linux/timekeeping.h
index 18d27a3f72ca00b357d90f43ba94d993760a551f..4c0f76f4616c78f299e79ae765817ef40a217f5c 100644 (file)
--- a/include/linux/timekeeping.h
+++ b/include/linux/timekeeping.h
@@ -268,6 +268,7 @@ static inline bool has_persistent_clock(void)
 }
 
 extern void read_persistent_clock(struct timespec *ts);
+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);

diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c
index 652e50a9c6ed4d4448b93bacca38ba1756fc6e9f..b1dbfa573dcedae9654f092c6c3548038e6a398f 100644 (file)
--- a/kernel/time/timekeeping.c
+++ b/kernel/time/timekeeping.c
@@ -1173,6 +1173,14 @@ void __weak read_persistent_clock(struct timespec *ts)
        ts->tv_nsec = 0;
 }
 
+void __weak read_persistent_clock64(struct timespec64 *ts64)
+{
+       struct timespec ts;
+
+       read_persistent_clock(&ts);
+       *ts64 = timespec_to_timespec64(ts);
+}
+
 /**
  * read_boot_clock -  Return time of the system start.
  *
@@ -1205,10 +1213,8 @@ void __init timekeeping_init(void)
        struct clocksource *clock;
        unsigned long flags;
        struct timespec64 now, boot, tmp;
-       struct timespec ts;
 
-       read_persistent_clock(&ts);
-       now = timespec_to_timespec64(ts);
+       read_persistent_clock64(&now);
        if (!timespec64_valid_strict(&now)) {
                pr_warn("WARNING: Persistent clock returned invalid value!\n"
                        "         Check your CMOS/BIOS settings.\n");
@@ -1278,7 +1284,7 @@ static void __timekeeping_inject_sleeptime(struct timekeeper *tk,
  * timekeeping_inject_sleeptime64 - Adds suspend interval to timeekeeping values
  * @delta: pointer to a timespec64 delta value
  *
- * This hook is for architectures that cannot support read_persistent_clock
+ * This hook is for architectures that cannot support read_persistent_clock64
  * because their RTC/persistent clock is only accessible when irqs are enabled.
  *
  * This function should only be called by rtc_resume(), and allows
@@ -1325,12 +1331,10 @@ void timekeeping_resume(void)
        struct clocksource *clock = tk->tkr_mono.clock;
        unsigned long flags;
        struct timespec64 ts_new, ts_delta;
-       struct timespec tmp;
        cycle_t cycle_now, cycle_delta;
        bool suspendtime_found = false;
 
-       read_persistent_clock(&tmp);
-       ts_new = timespec_to_timespec64(tmp);
+       read_persistent_clock64(&ts_new);
 
        clockevents_resume();
        clocksource_resume();
@@ -1406,10 +1410,8 @@ int timekeeping_suspend(void)
        unsigned long flags;
        struct timespec64               delta, delta_delta;
        static struct timespec64        old_delta;
-       struct timespec tmp;
 
-       read_persistent_clock(&tmp);
-       timekeeping_suspend_time = timespec_to_timespec64(tmp);
+       read_persistent_clock64(&timekeeping_suspend_time);
 
        /*
         * On some systems the persistent_clock can not be detected at