* [PATCH 2/3] drivers/clocksource/pistachio: Fix memory corruption in init
2016-08-26 14:20 ` [PATCH 1/3] clocksource/drivers/timer-atmel-pit: Enable mck clock Daniel Lezcano
@ 2016-08-26 14:20 ` Daniel Lezcano
2016-08-26 14:20 ` [PATCH 3/3] clocksource/drivers/sun4i: Clear interrupts after stopping timer in probe function Daniel Lezcano
2016-08-30 9:55 ` [PATCH 1/3] clocksource/drivers/timer-atmel-pit: Enable mck clock Mark Rutland
2 siblings, 0 replies; 6+ messages in thread
From: Daniel Lezcano @ 2016-08-26 14:20 UTC (permalink / raw)
To: linux-arm-kernel
From: Marcin Nowakowski <marcin.nowakowski@imgtec.com>
Driver init code incorrectly uses the block base address and as a result
clears clocksource structure's fields instead of the hardware registers.
Commit 09a998201649 ("timekeeping: Lift clocksource cacheline
restriction") has changed the offsets within pistachio_clocksource
structure and what has previously gone unnoticed now leads to a kernel
panic during boot.
Signed-off-by: Marcin Nowakowski <marcin.nowakowski@imgtec.com>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
---
drivers/clocksource/time-pistachio.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/drivers/clocksource/time-pistachio.c b/drivers/clocksource/time-pistachio.c
index a7d9a08..a8e6c7d 100644
--- a/drivers/clocksource/time-pistachio.c
+++ b/drivers/clocksource/time-pistachio.c
@@ -202,10 +202,10 @@ static int __init pistachio_clksrc_of_init(struct device_node *node)
rate = clk_get_rate(fast_clk);
/* Disable irq's for clocksource usage */
- gpt_writel(&pcs_gpt.base, 0, TIMER_IRQ_MASK, 0);
- gpt_writel(&pcs_gpt.base, 0, TIMER_IRQ_MASK, 1);
- gpt_writel(&pcs_gpt.base, 0, TIMER_IRQ_MASK, 2);
- gpt_writel(&pcs_gpt.base, 0, TIMER_IRQ_MASK, 3);
+ gpt_writel(pcs_gpt.base, 0, TIMER_IRQ_MASK, 0);
+ gpt_writel(pcs_gpt.base, 0, TIMER_IRQ_MASK, 1);
+ gpt_writel(pcs_gpt.base, 0, TIMER_IRQ_MASK, 2);
+ gpt_writel(pcs_gpt.base, 0, TIMER_IRQ_MASK, 3);
/* Enable timer block */
writel(TIMER_ME_GLOBAL, pcs_gpt.base);
--
1.9.1
^ permalink raw reply related [flat|nested] 6+ messages in thread* [PATCH 3/3] clocksource/drivers/sun4i: Clear interrupts after stopping timer in probe function
2016-08-26 14:20 ` [PATCH 1/3] clocksource/drivers/timer-atmel-pit: Enable mck clock Daniel Lezcano
2016-08-26 14:20 ` [PATCH 2/3] drivers/clocksource/pistachio: Fix memory corruption in init Daniel Lezcano
@ 2016-08-26 14:20 ` Daniel Lezcano
2016-08-30 9:55 ` [PATCH 1/3] clocksource/drivers/timer-atmel-pit: Enable mck clock Mark Rutland
2 siblings, 0 replies; 6+ messages in thread
From: Daniel Lezcano @ 2016-08-26 14:20 UTC (permalink / raw)
To: linux-arm-kernel
From: Chen-Yu Tsai <wens@csie.org>
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.
Cc: stable at vger.kernel.org
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>
---
drivers/clocksource/sun4i_timer.c | 9 ++++++++-
1 file changed, 8 insertions(+), 1 deletion(-)
diff --git a/drivers/clocksource/sun4i_timer.c b/drivers/clocksource/sun4i_timer.c
index 97669ee..c83452c 100644
--- a/drivers/clocksource/sun4i_timer.c
+++ b/drivers/clocksource/sun4i_timer.c
@@ -123,12 +123,16 @@ static struct clock_event_device sun4i_clockevent = {
.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;
@@ -208,6 +212,9 @@ static int __init sun4i_timer_init(struct device_node *node)
/* 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;
--
1.9.1
^ permalink raw reply related [flat|nested] 6+ messages in thread* [PATCH 1/3] clocksource/drivers/timer-atmel-pit: Enable mck clock
2016-08-26 14:20 ` [PATCH 1/3] clocksource/drivers/timer-atmel-pit: Enable mck clock Daniel Lezcano
2016-08-26 14:20 ` [PATCH 2/3] drivers/clocksource/pistachio: Fix memory corruption in init Daniel Lezcano
2016-08-26 14:20 ` [PATCH 3/3] clocksource/drivers/sun4i: Clear interrupts after stopping timer in probe function Daniel Lezcano
@ 2016-08-30 9:55 ` Mark Rutland
2016-08-30 10:15 ` Daniel Lezcano
2 siblings, 1 reply; 6+ messages in thread
From: Mark Rutland @ 2016-08-30 9:55 UTC (permalink / raw)
To: linux-arm-kernel
Hi,
On Fri, Aug 26, 2016 at 04:20:43PM +0200, Daniel Lezcano wrote:
> From: Alexandre Belloni <alexandre.belloni@free-electrons.com>
>
> mck is needed to get the PIT working. Explicitly prepare_enable it instead
> of assuming it is enabled.
>
> This solves an issue where the system is freezing when the ETM/ETB drivers
> are enabled.
>
> Reported-by: Olivier Schonken <olivier.schonken@gmail.com>
> Reviewed-by: Boris Brezillon <boris.brezillon@free-electrons.com>
> Acked-by: Nicolas Ferre <nicolas.ferre@atmel.com>
> Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
> Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
> ---
> drivers/clocksource/timer-atmel-pit.c | 6 ++++++
> 1 file changed, 6 insertions(+)
>
> diff --git a/drivers/clocksource/timer-atmel-pit.c b/drivers/clocksource/timer-atmel-pit.c
> index 1ffac0c..3494bc5 100644
> --- a/drivers/clocksource/timer-atmel-pit.c
> +++ b/drivers/clocksource/timer-atmel-pit.c
> @@ -261,6 +261,12 @@ static int __init at91sam926x_pit_dt_init(struct device_node *node)
> return PTR_ERR(data->mck);
> }
>
> + ret = clk_prepare_enable(data->mck);
> + if (ret) {
> + pr_err("Unable to enable mck\n");
> + return ret;
> + }
> +
Apologies if the below is a duplicate report.
When building v4.8-rc4 multi_v7_defconfig, I get:
[mark at leverpostej:~/src/linux]% uselinaro 15.08 make ARCH=arm CROSS_COMPILE=arm-linux-gnueabihf- -j10 -s
drivers/clocksource/timer-atmel-pit.c: In function 'at91sam926x_pit_dt_init':
drivers/clocksource/timer-atmel-pit.c:264:2: error: 'ret' undeclared (first use in this function)
ret = clk_prepare_enable(data->mck);
^
drivers/clocksource/timer-atmel-pit.c:264:2: note: each undeclared identifier is reported only once for each function it appears in
make[2]: *** [drivers/clocksource/timer-atmel-pit.o] Error 1
make[1]: *** [drivers/clocksource] Error 2
make[1]: *** Waiting for unfinished jobs....
make: *** [drivers] Error 2
As far as I can see, there's no local 'ret' variable. Locally I've fixed this
up with:
----8----
diff --git a/drivers/clocksource/timer-atmel-pit.c b/drivers/clocksource/timer-atmel-pit.c
index 3494bc5..7f0f5b2 100644
--- a/drivers/clocksource/timer-atmel-pit.c
+++ b/drivers/clocksource/timer-atmel-pit.c
@@ -240,6 +240,7 @@ static int __init at91sam926x_pit_common_init(struct pit_data *data)
static int __init at91sam926x_pit_dt_init(struct device_node *node)
{
struct pit_data *data;
+ int ret;
data = kzalloc(sizeof(*data), GFP_KERNEL);
if (!data)
---->8----
Thanks,
Mark.
^ permalink raw reply related [flat|nested] 6+ messages in thread