From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Date: Thu, 15 Sep 2016 17:21:40 +0000 (+0200)
Subject: 4.7-stable patches
X-Git-Tag: v4.4.22~23
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=efbaddd2edb09290ff2319c616ee688e086bb59d;p=thirdparty%2Fkernel%2Fstable-queue.git

4.7-stable patches

added patches:
	clocksource-drivers-sun4i-clear-interrupts-after-stopping-timer-in-probe-function.patch
---

diff --git a/queue-4.7/clocksource-drivers-sun4i-clear-interrupts-after-stopping-timer-in-probe-function.patch b/queue-4.7/clocksource-drivers-sun4i-clear-interrupts-after-stopping-timer-in-probe-function.patch
new file mode 100644
index 00000000000..c7f8a3631f5
--- /dev/null
+++ b/queue-4.7/clocksource-drivers-sun4i-clear-interrupts-after-stopping-timer-in-probe-function.patch
@@ -0,0 +1,62 @@
+From b53e7d000d9e6e9fd2c6eb6b82d2783c67fd599e Mon Sep 17 00:00:00 2001
+From: Chen-Yu Tsai <wens@csie.org>
+Date: Thu, 25 Aug 2016 14:26:59 +0800
+Subject: clocksource/drivers/sun4i: Clear interrupts after stopping timer in probe function
+
+From: Chen-Yu Tsai <wens@csie.org>
+
+commit b53e7d000d9e6e9fd2c6eb6b82d2783c67fd599e upstream.
+
+The bootloader (U-boot) sometimes uses this timer for various delays.
+It uses it as a ongoing counter, and does comparisons on the current
+counter value. The timer counter is never stopped.
+
+In some cases when the user interacts with the bootloader, or lets
+it idle for some time before loading Linux, the timer may expire,
+and an interrupt will be pending. This results in an unexpected
+interrupt when the timer interrupt is enabled by the kernel, at
+which point the event_handler isn't set yet. This results in a NULL
+pointer dereference exception, panic, and no way to reboot.
+
+Clear any pending interrupts after we stop the timer in the probe
+function to avoid this.
+
+Signed-off-by: Chen-Yu Tsai <wens@csie.org>
+Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
+Acked-by: Maxime Ripard <maxime.ripard@free-electrons.com>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+
+---
+ drivers/clocksource/sun4i_timer.c |    9 ++++++++-
+ 1 file changed, 8 insertions(+), 1 deletion(-)
+
+--- a/drivers/clocksource/sun4i_timer.c
++++ b/drivers/clocksource/sun4i_timer.c
+@@ -123,12 +123,16 @@ static struct clock_event_device sun4i_c
+ 	.set_next_event = sun4i_clkevt_next_event,
+ };
+ 
++static void sun4i_timer_clear_interrupt(void)
++{
++	writel(TIMER_IRQ_EN(0), timer_base + TIMER_IRQ_ST_REG);
++}
+ 
+ static irqreturn_t sun4i_timer_interrupt(int irq, void *dev_id)
+ {
+ 	struct clock_event_device *evt = (struct clock_event_device *)dev_id;
+ 
+-	writel(0x1, timer_base + TIMER_IRQ_ST_REG);
++	sun4i_timer_clear_interrupt();
+ 	evt->event_handler(evt);
+ 
+ 	return IRQ_HANDLED;
+@@ -193,6 +197,9 @@ static void __init sun4i_timer_init(stru
+ 	/* Make sure timer is stopped before playing with interrupts */
+ 	sun4i_clkevt_time_stop(0);
+ 
++	/* clear timer0 interrupt */
++	sun4i_timer_clear_interrupt();
++
+ 	sun4i_clockevent.cpumask = cpu_possible_mask;
+ 	sun4i_clockevent.irq = irq;
+ 
diff --git a/queue-4.7/series b/queue-4.7/series
new file mode 100644
index 00000000000..b5988a897b2
--- /dev/null
+++ b/queue-4.7/series
@@ -0,0 +1 @@
+clocksource-drivers-sun4i-clear-interrupts-after-stopping-timer-in-probe-function.patch