[PATCH 0/8] Add y2038 safe replacements for read_boot_clock(), read_persistent_clock() and update_persistent_clock()

[PATCH 0/8] Add y2038 safe replacements for read_boot_clock(), read_persistent_clock() and update_persistent_clock()

[Xunlei Pang]

From: Xunlei Pang <pang.xunlei-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>

read_boot_clock(), read_persistent_clock() and update_persistent_clock()
all use timespec which may have "y2038 problem", thus we are planning on
converting all of them to use timespec64.

The approach we're using is:
1) First of all, add the "__weak" implementaion of xxx_clock64() which uses
   xxx_clock() and timespec64.

   Let's take read_persistent_clock() as an example. We can create its
   y2038-safe version below:
        void __weak read_persistent_clock64(struct timespec64 *ts64)
        {
             struct timespec ts;

            read_persistent_clock(&ts);
            *ts64 = timespec_to_timespec64(ts);
        }

   Then, replace all the call sites of xxx_clock() with xxx_clock64() except
   the one used by xxx_clock64().

2) Convert every architecture specific xxx_clock() to xxx_clock64() one by one.
   At this point, we can convert the three functions at a time if needed, because
   most time they're correlated.

3) Remove xxx_clock() after all its architecture specific implementations have been
   converted to use corresponding y2038 safe xxx_clock64().

This patchset firstly finished the step1 for all the three functions, then focused
on read_boot_clock() which is simple to go on with step2 and step3 as a whole show.

As for read_persistent_clock() and update_persistent_clock() which are more complex,
requiring many efforts to convert every architecture specific implementation gradually.

The approach used here is Suggested-by: "Arnd Bergmann <arnd-r2nGTMty4D4@public.gmane.org>"

Xunlei Pang (8):
  time: Add y2038 safe read_boot_clock64()
  time: Add y2038 safe read_persistent_clock64()
  time: Add y2038 safe update_persistent_clock64()
  ARM: OMAP: 32k counter: Provide y2038-safe
    omap_read_persistent_clock() replacement
  ARM: tegra: clock: Provide y2038-safe tegra_read_persistent_clock()
    replacement
  ARM: time: Provide read_boot_clock64() and read_persistent_clock64()
  s390: time: Provide read_boot_clock64() and read_persistent_clock64()
  time: Remove read_boot_clock()

 arch/arm/include/asm/mach/time.h    |  3 +--
 arch/arm/kernel/time.c              |  6 +++---
 arch/arm/plat-omap/counter_32k.c    | 18 ++++++------------
 arch/mips/lasat/sysctl.c            |  4 ++--
 arch/s390/include/asm/timex.h       |  4 ++--
 arch/s390/kernel/debug.c            |  4 ++--
 arch/s390/kernel/time.c             |  6 +++---
 drivers/clocksource/tegra20_timer.c | 15 +++++++--------
 drivers/rtc/systohc.c               |  2 +-
 include/linux/timekeeping.h         |  4 +++-
 kernel/time/ntp.c                   | 13 ++++++++++++-
 kernel/time/timekeeping.c           | 31 ++++++++++++++++---------------
 12 files changed, 58 insertions(+), 52 deletions(-)

-- 
1.9.1

[PATCH 1/8] time: Add y2038 safe read_boot_clock64()

[Xunlei Pang]

From: Xunlei Pang <pang.xunlei-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>

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-r2nGTMty4D4@public.gmane.org>
Signed-off-by: Xunlei Pang <pang.xunlei-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>
---
 include/linux/timekeeping.h |  1 +
 kernel/time/timekeeping.c   | 11 +++++++++--
 2 files changed, 10 insertions(+), 2 deletions(-)

diff --git a/include/linux/timekeeping.h b/include/linux/timekeeping.h
index 3eaae47..d53c522 100644
--- a/include/linux/timekeeping.h
+++ b/include/linux/timekeeping.h
@@ -263,6 +263,7 @@ 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 91db941..7080c21 100644
--- a/kernel/time/timekeeping.c
+++ b/kernel/time/timekeeping.c
@@ -1072,6 +1072,14 @@ 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
  */
@@ -1093,8 +1101,7 @@ 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");
-- 
1.9.1

Re: [PATCH 1/8] time: Add y2038 safe read_boot_clock64()

[John Stultz]

On Wed, Mar 18, 2015 at 5:48 AM,  <pang.xunlei@zte.com.cn> wrote:
> Ping ...

Thanks for the reminder. Since there's not been any objections, I'm
queuing this up.

thanks
-john

[PATCH 2/8] time: Add y2038 safe read_persistent_clock64()

[Xunlei Pang]

From: Xunlei Pang <pang.xunlei-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>

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-r2nGTMty4D4@public.gmane.org>
Signed-off-by: Xunlei Pang <pang.xunlei-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>
---
 arch/mips/lasat/sysctl.c    |  4 ++--
 include/linux/timekeeping.h |  1 +
 kernel/time/timekeeping.c   | 22 ++++++++++++----------
 3 files changed, 15 insertions(+), 12 deletions(-)

diff --git a/arch/mips/lasat/sysctl.c b/arch/mips/lasat/sysctl.c
index 3b7f65c..cf9b4633 100644
--- 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 d53c522..ff56a0f 100644
--- a/include/linux/timekeeping.h
+++ b/include/linux/timekeeping.h
@@ -262,6 +262,7 @@ 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 7080c21..0e5a696 100644
--- a/kernel/time/timekeeping.c
+++ b/kernel/time/timekeeping.c
@@ -1057,6 +1057,14 @@ 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.
  *
@@ -1089,10 +1097,8 @@ 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");
@@ -1163,7 +1169,7 @@ 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
@@ -1210,12 +1216,10 @@ void timekeeping_resume(void)
 	struct clocksource *clock = tk->tkr.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();
@@ -1291,10 +1295,8 @@ 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
-- 
1.9.1

[PATCH 3/8] time: Add y2038 safe update_persistent_clock64()

[Xunlei Pang]

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().

Suggested-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Xunlei Pang <pang.xunlei@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 ff56a0f..a7fa96b 100644
--- a/include/linux/timekeeping.h
+++ b/include/linux/timekeeping.h
@@ -266,6 +266,7 @@ 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

[PATCH 4/8] ARM: OMAP: 32k counter: Provide y2038-safe omap_read_persistent_clock() replacement

[Xunlei Pang]

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

As part of addressing "y2038 problem" for in-kernel uses, this
patch adds the y2038-safe omap_read_persistent_clock64() using
timespec64.

Because we rely on some subsequent changes to convert arm multiarch
support, omap_read_persistent_clock() will be removed then.

Also remove the needless spinlock, because read_persistent_clock()
doesn't run simultaneously.

Signed-off-by: Xunlei Pang <pang.xunlei@linaro.org>
---
 arch/arm/plat-omap/counter_32k.c | 22 ++++++++++++----------
 1 file changed, 12 insertions(+), 10 deletions(-)

diff --git a/arch/arm/plat-omap/counter_32k.c b/arch/arm/plat-omap/counter_32k.c
index 61b4d70..d422e36 100644
--- a/arch/arm/plat-omap/counter_32k.c
+++ b/arch/arm/plat-omap/counter_32k.c
@@ -44,24 +44,20 @@ static u64 notrace omap_32k_read_sched_clock(void)
 }
 
 /**
- * omap_read_persistent_clock -  Return time from a persistent clock.
+ * omap_read_persistent_clock64 -  Return time from a persistent clock.
  *
  * Reads the time from a source which isn't disabled during PM, the
  * 32k sync timer.  Convert the cycles elapsed since last read into
- * nsecs and adds to a monotonically increasing timespec.
+ * nsecs and adds to a monotonically increasing timespec64.
  */
-static struct timespec persistent_ts;
+static struct timespec64 persistent_ts;
 static cycles_t cycles;
 static unsigned int persistent_mult, persistent_shift;
-static DEFINE_SPINLOCK(read_persistent_clock_lock);
 
-static void omap_read_persistent_clock(struct timespec *ts)
+static void omap_read_persistent_clock64(struct timespec64 *ts)
 {
 	unsigned long long nsecs;
 	cycles_t last_cycles;
-	unsigned long flags;
-
-	spin_lock_irqsave(&read_persistent_clock_lock, flags);
 
 	last_cycles = cycles;
 	cycles = sync32k_cnt_reg ? readl_relaxed(sync32k_cnt_reg) : 0;
@@ -69,11 +65,17 @@ static void omap_read_persistent_clock(struct timespec *ts)
 	nsecs = clocksource_cyc2ns(cycles - last_cycles,
 					persistent_mult, persistent_shift);
 
-	timespec_add_ns(&persistent_ts, nsecs);
+	timespec64_add_ns(&persistent_ts, nsecs);
 
 	*ts = persistent_ts;
+}
+
+static void omap_read_persistent_clock(struct timespec *ts)
+{
+	struct timespec64 ts64;
 
-	spin_unlock_irqrestore(&read_persistent_clock_lock, flags);
+	omap_read_persistent_clock64(&ts64);
+	*ts = timespec64_to_timespec(ts64);
 }
 
 /**
-- 
1.9.1

Re: [PATCH 4/8] ARM: OMAP: 32k counter: Provide y2038-safe omap_read_persistent_clock() replacement

[Tony Lindgren]

* Xunlei Pang <xlpang@126.com> [150310 20:18]:
> From: Xunlei Pang <pang.xunlei@linaro.org>
> 
> As part of addressing "y2038 problem" for in-kernel uses, this
> patch adds the y2038-safe omap_read_persistent_clock64() using
> timespec64.
> 
> Because we rely on some subsequent changes to convert arm multiarch
> support, omap_read_persistent_clock() will be removed then.
> 
> Also remove the needless spinlock, because read_persistent_clock()
> doesn't run simultaneously.
> 
> Signed-off-by: Xunlei Pang <pang.xunlei@linaro.org>

Looks OK to me:

Acked-by: Tony Lindgren <tony@atomide.com>

> ---
>  arch/arm/plat-omap/counter_32k.c | 22 ++++++++++++----------
>  1 file changed, 12 insertions(+), 10 deletions(-)
> 
> diff --git a/arch/arm/plat-omap/counter_32k.c b/arch/arm/plat-omap/counter_32k.c
> index 61b4d70..d422e36 100644
> --- a/arch/arm/plat-omap/counter_32k.c
> +++ b/arch/arm/plat-omap/counter_32k.c
> @@ -44,24 +44,20 @@ static u64 notrace omap_32k_read_sched_clock(void)
>  }
>  
>  /**
> - * omap_read_persistent_clock -  Return time from a persistent clock.
> + * omap_read_persistent_clock64 -  Return time from a persistent clock.
>   *
>   * Reads the time from a source which isn't disabled during PM, the
>   * 32k sync timer.  Convert the cycles elapsed since last read into
> - * nsecs and adds to a monotonically increasing timespec.
> + * nsecs and adds to a monotonically increasing timespec64.
>   */
> -static struct timespec persistent_ts;
> +static struct timespec64 persistent_ts;
>  static cycles_t cycles;
>  static unsigned int persistent_mult, persistent_shift;
> -static DEFINE_SPINLOCK(read_persistent_clock_lock);
>  
> -static void omap_read_persistent_clock(struct timespec *ts)
> +static void omap_read_persistent_clock64(struct timespec64 *ts)
>  {
>  	unsigned long long nsecs;
>  	cycles_t last_cycles;
> -	unsigned long flags;
> -
> -	spin_lock_irqsave(&read_persistent_clock_lock, flags);
>  
>  	last_cycles = cycles;
>  	cycles = sync32k_cnt_reg ? readl_relaxed(sync32k_cnt_reg) : 0;
> @@ -69,11 +65,17 @@ static void omap_read_persistent_clock(struct timespec *ts)
>  	nsecs = clocksource_cyc2ns(cycles - last_cycles,
>  					persistent_mult, persistent_shift);
>  
> -	timespec_add_ns(&persistent_ts, nsecs);
> +	timespec64_add_ns(&persistent_ts, nsecs);
>  
>  	*ts = persistent_ts;
> +}
> +
> +static void omap_read_persistent_clock(struct timespec *ts)
> +{
> +	struct timespec64 ts64;
>  
> -	spin_unlock_irqrestore(&read_persistent_clock_lock, flags);
> +	omap_read_persistent_clock64(&ts64);
> +	*ts = timespec64_to_timespec(ts64);
>  }
>  
>  /**
> -- 
> 1.9.1
> 
>