Use of rtems_fdt_* and sp01

[Sebastian Huber]

On 18/11/2022 06:32, Kinsey Moore wrote:
> On Thu, Nov 17, 2022 at 4:49 PM Chris Johns <chrisj at rtems.org 
> <mailto:chrisj at rtems.org>> wrote:
> 
>     On 18/11/2022 2:39 am, Kinsey Moore wrote:
>      > I recently added FDT support to the AArch64 ZynqMP BSPs to
>     support an optional
>      > management console and managing ethernet parameters for LibBSD.
>     Use of the
>      > rtems_fdt_* functions implies use of malloc which adds 4 bytes in
>     the TLS space.
>      > The sp01 test uses rtems_task_construct and specifies a maximum
>     TLS size of 0
>      > bytes which causes a failure which the non-zero TLS size is
>     checked against the
>      > maximum TLS size of 0.
> 
>     Does this mean there exists a requirement a BSPs cannot internally
>     use the heap?
> 
> 
> That appears to be the case, at least practically. It works fine, but it 
> causes a test failure...

You can use the heap during system initialization. However, you should 
avoid dependencies on errno, so instead of using malloc()/calloc() use 
rtems_malloc()/rtems_calloc(). Independent of this, if the BSP 
initialization can easily avoid the heap, then it should not use the heap.

> 
> 
>     Maybe the test needs to be adjusted?
> 
> 
> That's part of why I sent this to the list. I was unsure whether it was 
> allowed or whether the test had bad assumptions baked into it.

The tests check specific aspects of the thread-local storage support and 
this works only if the BSP does not depend on TLS objects such as errno.

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