Task sync problems related with binary semaphore and cache memories

[Sebastian Huber]

On 28/11/2018 11:30, Arturo Perez Garcia wrote:
> Disabling the caches don't fixe the problem, I was wrong.
>
> Maybe I'm initializing wrongly the RTEMS objects.
>
> In the Init task I create the binary semaphore:
>
>        rtems_semaphore_create(a3_sem_name, 1, RTEMS_BINARY_SEMAPHORE | 
> RTEMS_FIFO | RTEMS_LOCAL, 0, &a3_sem_id);
>
> Then I create 2 tasks with different priority:
>
>     rtems_task_create(
>         t_matmul_name, 1, RTEMS_MINIMUM_STACK_SIZE * 2, RTEMS_PREEMPT,
>         RTEMS_LOCAL, &t_matmul_id
>     );
>
>     rtems_task_create(
>         t_inout_name, 2, RTEMS_MINIMUM_STACK_SIZE * 2, RTEMS_PREEMPT,
>         RTEMS_LOCAL, &t_inout_id
>     );
>
> The tasks must be synchronized through the semaphore, but they are 
> not. The semaphore is acquired by both tasks consecutively before it 
> has been released.
>
> I suppose that it is due to an error in my BSP implementation, but I 
> don't know how to test it. 

Did you test that the returned status code is RTEMS_SUCCESSFUL in all cases?

-- 
Sebastian Huber, embedded brains GmbH

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