[Qemu-arm] [PATCH] timer: stm32f2xx_timer: add check for prescaler value

[P J P]

From: Prasad J Pandit <address@hidden>

The STM32F2XX Timer emulator uses a 16 bit prescaler value to
limit the timer clock rate. It does that by dividing the timer
frequency. If the prescaler 's->tim_psc' was set to be UINT_MAX,
it'd lead to divide by zero error. Limit prescaler value to 16
bits to avoid it.

Reported-by: Huawei PSIRT <address@hidden>
Signed-off-by: Prasad J Pandit <address@hidden>
---
 hw/timer/stm32f2xx_timer.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/hw/timer/stm32f2xx_timer.c b/hw/timer/stm32f2xx_timer.c
index bf0fb28..2cad36d 100644
--- a/hw/timer/stm32f2xx_timer.c
+++ b/hw/timer/stm32f2xx_timer.c
@@ -208,7 +208,7 @@ static void stm32f2xx_timer_write(void *opaque, hwaddr 
offset,
         return;
     case TIM_PSC:
         timer_val = stm32f2xx_ns_to_ticks(s, now) - s->tick_offset;
-        s->tim_psc = value;
+        s->tim_psc = value & 0xFFFF;
         value = timer_val;
         break;
     case TIM_CNT:
-- 
2.7.4