[PATCH rtems] bsps/arm: Fix uninitialized value in generic timer

[Sebastian Huber]

On 16/04/2020 14:21, Christian Mauderer wrote:
> _CPU_Counter_frequency() can be called by the rtems_counter
> initialization before arm_gt_clock_initialize() initializes the value
> used in _CPU_Counter_frequency().
>
> Update #3456.
> ---
>   bsps/arm/shared/clock/clock-generic-timer.c | 10 ++++++++--
>   1 file changed, 8 insertions(+), 2 deletions(-)
>
> diff --git a/bsps/arm/shared/clock/clock-generic-timer.c b/bsps/arm/shared/clock/clock-generic-timer.c
> index 1f39632ba6..a0efb9c7ed 100644
> --- a/bsps/arm/shared/clock/clock-generic-timer.c
> +++ b/bsps/arm/shared/clock/clock-generic-timer.c
> @@ -161,7 +161,6 @@ static void arm_gt_clock_initialize(void)
>     tc = &arm_gt_clock_instance.tc;
>     tc->tc_get_timecount = arm_gt_clock_get_timecount;
>     tc->tc_counter_mask = 0xffffffff;
> -  tc->tc_frequency = frequency;
>     tc->tc_quality = RTEMS_TIMECOUNTER_QUALITY_CLOCK_DRIVER;
>     rtems_timecounter_install(tc);
>   }
> @@ -178,12 +177,19 @@ CPU_Counter_ticks _CPU_Counter_read(void)
>   
>   static void arm_gt_clock_early_init(void)
>   {
> +  uint32_t frequency;
>     arm_gt_clock_set_control(0x3);
>   
>     arm_generic_timer_get_config(
> -    &arm_gt_clock_instance.interval,
> +    &frequency,
>       &arm_gt_clock_instance.irq
>     );
> +
> +  /* Used by _CPU_Counter_frequency before arm_gt_clock_initialize is called */
Please use func() in the comments.
> +  arm_gt_clock_instance.tc.tc_frequency = frequency;
> +
> +  /* overwritten with the calculated interval by arm_gt_clock_initialize */
> +  arm_gt_clock_instance.interval = frequency;
I would remove this assignment here and read the frequency in 
arm_gt_clock_initialize() like this:

   tc = &arm_gt_clock_instance.tc;
   frequency = (uint32_t) tc->tc_frequency;
  

>   }
>   
>   RTEMS_SYSINIT_ITEM(