Re: [Qemu-devel] [PATCH] hw/timer/grlib_gptimer: Avoid integer overflow

[Peter Maydell <peter.maydell@linaro.org>]

On 13 February 2014 09:16, Sebastian Huber
<sebastian.huber@embedded-brains.de> wrote:
> The GPTIMER uses 32-bit registers.  Use a 64-bit operation to get the
> ptimer count, otherwise we end up with a count of 0 for GPTIMER counter
> values of 0xffffffff.
> ---
>  hw/timer/grlib_gptimer.c |    4 ++--
>  1 files changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/hw/timer/grlib_gptimer.c b/hw/timer/grlib_gptimer.c
> index d5687f6..343563c 100644
> --- a/hw/timer/grlib_gptimer.c
> +++ b/hw/timer/grlib_gptimer.c
> @@ -106,9 +106,9 @@ static void grlib_gptimer_enable(GPTimer *timer)
>      /* ptimer is triggered when the counter reach 0 but GPTimer is triggered at
>         underflow. Set count + 1 to simulate the GPTimer behavior. */
>
> -    trace_grlib_gptimer_enable(timer->id, timer->counter + 1);
> +    trace_grlib_gptimer_enable(timer->id, timer->counter);

This change isn't mentioned in the commit message...

> -    ptimer_set_count(timer->ptimer, timer->counter + 1);
> +    ptimer_set_count(timer->ptimer, (uint64_t)timer->counter + 1);
>      ptimer_run(timer->ptimer, 1);
>  }

thanks
-- PMM