The patch titled Subject: rtc: armada38x: fix concurrency access in armada38x_rtc_set_time has been removed from the -mm tree. Its filename was rtc-armada38x-fix-concurrency-access-in-armada38x_rtc_set_time.patch This patch was dropped because it was merged into mainline or a subsystem tree ------------------------------------------------------ From: Gregory CLEMENT <gregory.clement@xxxxxxxxxxxxxxxxxx> Subject: rtc: armada38x: fix concurrency access in armada38x_rtc_set_time While setting the time, the RTC TIME register should not be accessed. However due to hardware constraints, setting the RTC time involves sleeping during 100ms. This sleep was done outside the critical section protected by the spinlock, so it was possible to read the RTC TIME register and get an incorrect value. This patch introduces a mutex for protecting the RTC TIME access, unlike the spinlock it is allowed to sleep in a critical section protected by a mutex. The RTC STATUS register can still be used from the interrupt handler but it has no effect on setting the time. Signed-off-by: Gregory CLEMENT <gregory.clement@xxxxxxxxxxxxxxxxxx> Acked-by: Alexandre Belloni <alexandre.belloni@xxxxxxxxxxxxxxxxxx> Acked-by: Andrew Lunn <andrew@xxxxxxx> Cc: Alessandro Zummo <a.zummo@xxxxxxxxxxxx> Cc: <stable@xxxxxxxxxxxxxxx> [4.0] Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- drivers/rtc/rtc-armada38x.c | 24 ++++++++++++------------ 1 file changed, 12 insertions(+), 12 deletions(-) diff -puN drivers/rtc/rtc-armada38x.c~rtc-armada38x-fix-concurrency-access-in-armada38x_rtc_set_time drivers/rtc/rtc-armada38x.c --- a/drivers/rtc/rtc-armada38x.c~rtc-armada38x-fix-concurrency-access-in-armada38x_rtc_set_time +++ a/drivers/rtc/rtc-armada38x.c @@ -40,6 +40,13 @@ struct armada38x_rtc { void __iomem *regs; void __iomem *regs_soc; spinlock_t lock; + /* + * While setting the time, the RTC TIME register should not be + * accessed. Setting the RTC time involves sleeping during + * 100ms, so a mutex instead of a spinlock is used to protect + * it + */ + struct mutex mutex_time; int irq; }; @@ -59,8 +66,7 @@ static int armada38x_rtc_read_time(struc struct armada38x_rtc *rtc = dev_get_drvdata(dev); unsigned long time, time_check, flags; - spin_lock_irqsave(&rtc->lock, flags); - + mutex_lock(&rtc->mutex_time); time = readl(rtc->regs + RTC_TIME); /* * WA for failing time set attempts. As stated in HW ERRATA if @@ -71,7 +77,7 @@ static int armada38x_rtc_read_time(struc if ((time_check - time) > 1) time_check = readl(rtc->regs + RTC_TIME); - spin_unlock_irqrestore(&rtc->lock, flags); + mutex_unlock(&rtc->mutex_time); rtc_time_to_tm(time_check, tm); @@ -94,19 +100,12 @@ static int armada38x_rtc_set_time(struct * then wait for 100ms before writing to the time register to be * sure that the data will be taken into account. */ - spin_lock_irqsave(&rtc->lock, flags); - + mutex_lock(&rtc->mutex_time); rtc_delayed_write(0, rtc, RTC_STATUS); - - spin_unlock_irqrestore(&rtc->lock, flags); - msleep(100); - - spin_lock_irqsave(&rtc->lock, flags); - rtc_delayed_write(time, rtc, RTC_TIME); + mutex_unlock(&rtc->mutex_time); - spin_unlock_irqrestore(&rtc->lock, flags); out: return ret; } @@ -230,6 +229,7 @@ static __init int armada38x_rtc_probe(st return -ENOMEM; spin_lock_init(&rtc->lock); + mutex_init(&rtc->mutex_time); res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "rtc"); rtc->regs = devm_ioremap_resource(&pdev->dev, res); _ Patches currently in -mm which might be from gregory.clement@xxxxxxxxxxxxxxxxxx are origin.patch linux-next.patch -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html