[RTEMS Project] #4243: rtems_cache_coherent_allocate fallback is to return heap memory

[RTEMS trac]

#4243: rtems_cache_coherent_allocate fallback is to return heap memory
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 Reporter:  Chris Johns  |       Owner:  (none)
     Type:  defect       |      Status:  new
 Priority:  normal       |   Milestone:  6.1
Component:  lib          |     Version:  6
 Severity:  normal       |  Resolution:
 Keywords:               |  Blocked By:
 Blocking:               |
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Comment (by Chris Johns):

 Replying to [comment:2 Sebastian Huber]:
 > The fall back is correct for systems in which all memory is cache
 coherent also for DMA.

 It is not correct for a call of this type to make **any** assumption other
 than returning memory from the pool it has been given.

 > This is the case for all modern PowerPC systems. It is the
 responsibility of the BSP to provide a cache coherent memory pool if it is
 needed.

 If a BSP has a specific ability to do this then why not provide some
 memory from the malloc heap to the cache coherent allocator? I see not
 doing this as a bug in those BSPs that needs to be fixed. I do not agree
 with hiding something like this in a call as it currently is. A call in a
 BSP makes it easy to determine the intended mode of operation.

 I hope you understand that have I tripped over this and I will not be the
 last. Generating an error makes it easy to see you need to sort this issue
 out in a BSP.

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Ticket URL: <http://devel.rtems.org/ticket/4243#comment:3>
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