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MMU support questions



On Mar 28, 2011, at 11:13 , quanming shi wrote:

> what will be the main use of the MMU Support API ? OS like MinixPPC allow load module dynamicly, and the need to protect the page memory allocated to the process. But RTEMS don't support dynamic load function.

Many of us load the process into memory over the network using a boot loader.  Protecting the code after loading is applicable in that situation as well.  You'll need to pay attention to dynamically generated wrappers, etc, that may be used on some architectures.

Other items I'd like to see related to MMU support are:

- Unmapping the zero page to trap NULL pointer dereferences;
- Having an option for stacks that are private per task.  This means shared objects can't live on the stack, but I've worked on such systems and don't consider it a show-stopper;
- Making private heap regions that are only activated when a task is activated.  Again, obviously shared objects can't live in those regions.

Peter
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Peter Dufault
HD Associates, Inc.      Software and System Engineering