The progress of RTEMS MMU Support

[quanming shi]

RTEMS MMU support project report


This project's target is adding an Access Domain Manager API to RTEMS. The
project is being done in the PSIM environment. It should be easy to export
the API to other boards or other architectures in the future.

The API will  manage an ALUT（access lookup table), and update the page table
or TLB as necessary.
The ALUT will contain ACBs(Access Control Blocks). This data structure
willhave the following information stored in
it.

 ACB ID
 Address PointerAddress Space LengthAccess Attribute
The API will use the ACB ID to search for and modify the information . I
think that will be better than using the address directly.

The API list is as shown below.  I will complete the user manual of the API
first.


   - creat_domain( start_address, size, attribute)
   - set_attr(ID, & new_attribute)
   - obtain_ID (address)
   - obtain_address( ID, &address, &size)
   - obtain_attr(ID, &attr)
   - update_size(ID, &new_size)
   - delete_domain(ID)
   - get_default_attr()
   - set_default_attr(new_attr)

The posix API will be considered after the classic API is implemented.

Right now I am having a strange problem in the PSIM environment.
Although the MSR is set as expected, PTEG , SPTEG , tlb are all flushed, the
DSI exception is still never taken.
if  anyone has met this kind of problem or has any debugging suggestions,
please share your idea with me. That will help me a lot.

And any suggestion about the API function design will be appreciated.


-- 
Best regards

Quanming Shi
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