Use of rtems_fdt_* and sp01

[Sebastian Huber]

On 18/11/2022 15:49, Kinsey Moore wrote:
> 
> On Fri, Nov 18, 2022 at 12:44 AM Sebastian Huber 
> <sebastian.huber at embedded-brains.de 
> <mailto:sebastian.huber at embedded-brains.de>> wrote:
> 
>     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>
>      > <mailto: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.
> 
> This affects several other tests as well, so I guess my solution here is 
> either to alter the rtems_fdt_ wrappers to avoid dependencies on TLS or 
> proceed with the existing patch that uses the non-wrapped FDT functions.

Your patch is pretty straight forward and gets rid of a heap usage 
during initialization. I would check it in anyway.

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