linux-kernel - [PATCH 1/3] rtc: vr41xx: remove mktime usage

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Date:   Fri, 20 Apr 2018 18:14:24 +0200
From:   Arnd Bergmann <arnd@...db.de>
To:     Alessandro Zummo <a.zummo@...ertech.it>,
        Alexandre Belloni <alexandre.belloni@...tlin.com>
Cc:     y2038@...ts.linaro.org, Arnd Bergmann <arnd@...db.de>,
        linux-rtc@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [PATCH 1/3] rtc: vr41xx: remove mktime usage

This driver uses mktime() and rtc_time_to_tm() to convert between time
values. This works fine on 64-bit kernels over the whole supported
range, and the vr41xx chip is a 64-bit MIPS implementation, but it is
inconsistent because it doesn't do the same thing on 32-bit kernels that
overflow in 2106 or 2038.

Changing it to use mktime64/rtc_time64_to_tm() should have no visible
impact on vr41xx but gets us closer to removing the 32-bit interfaces.

Signed-off-by: Arnd Bergmann <arnd@...db.de>
---
 drivers/rtc/rtc-vr41xx.c | 24 ++++++++++++------------
 1 file changed, 12 insertions(+), 12 deletions(-)

diff --git a/drivers/rtc/rtc-vr41xx.c b/drivers/rtc/rtc-vr41xx.c
index 7ce22967fd16..480cffe8d321 100644
--- a/drivers/rtc/rtc-vr41xx.c
+++ b/drivers/rtc/rtc-vr41xx.c
@@ -88,7 +88,7 @@ static unsigned int alarm_enabled;
 static int aie_irq;
 static int pie_irq;
 
-static inline unsigned long read_elapsed_second(void)
+static inline time64_t read_elapsed_second(void)
 {
 
 	unsigned long first_low, first_mid, first_high;
@@ -105,10 +105,10 @@ static inline unsigned long read_elapsed_second(void)
 	} while (first_low != second_low || first_mid != second_mid ||
 		 first_high != second_high);
 
-	return (first_high << 17) | (first_mid << 1) | (first_low >> 15);
+	return ((u64)first_high << 17) | (first_mid << 1) | (first_low >> 15);
 }
 
-static inline void write_elapsed_second(unsigned long sec)
+static inline void write_elapsed_second(time64_t sec)
 {
 	spin_lock_irq(&rtc_lock);
 
@@ -121,22 +121,22 @@ static inline void write_elapsed_second(unsigned long sec)
 
 static int vr41xx_rtc_read_time(struct device *dev, struct rtc_time *time)
 {
-	unsigned long epoch_sec, elapsed_sec;
+	time64_t epoch_sec, elapsed_sec;
 
-	epoch_sec = mktime(epoch, 1, 1, 0, 0, 0);
+	epoch_sec = mktime64(epoch, 1, 1, 0, 0, 0);
 	elapsed_sec = read_elapsed_second();
 
-	rtc_time_to_tm(epoch_sec + elapsed_sec, time);
+	rtc_time64_to_tm(epoch_sec + elapsed_sec, time);
 
 	return 0;
 }
 
 static int vr41xx_rtc_set_time(struct device *dev, struct rtc_time *time)
 {
-	unsigned long epoch_sec, current_sec;
+	time64_t epoch_sec, current_sec;
 
-	epoch_sec = mktime(epoch, 1, 1, 0, 0, 0);
-	current_sec = mktime(time->tm_year + 1900, time->tm_mon + 1, time->tm_mday,
+	epoch_sec = mktime64(epoch, 1, 1, 0, 0, 0);
+	current_sec = mktime64(time->tm_year + 1900, time->tm_mon + 1, time->tm_mday,
 			     time->tm_hour, time->tm_min, time->tm_sec);
 
 	write_elapsed_second(current_sec - epoch_sec);
@@ -165,11 +165,11 @@ static int vr41xx_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *wkalrm)
 
 static int vr41xx_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *wkalrm)
 {
-	unsigned long alarm_sec;
+	time64_t alarm_sec;
 	struct rtc_time *time = &wkalrm->time;
 
-	alarm_sec = mktime(time->tm_year + 1900, time->tm_mon + 1, time->tm_mday,
-			   time->tm_hour, time->tm_min, time->tm_sec);
+	alarm_sec = mktime64(time->tm_year + 1900, time->tm_mon + 1, time->tm_mday,
+			     time->tm_hour, time->tm_min, time->tm_sec);
 
 	spin_lock_irq(&rtc_lock);
 
-- 
2.9.0