Okay so this lab is fairly difficult, but it is also fairly straight forward. Much of the difficulty comes from debugging problems most of us have no experience with.
I have given an overview of the Lab, which I may do an update to if I have time; a thing I am currently fairly short of, and I will now give some tips for debugging I have learned to hopefully help minimize your debugging time. I could give a more in depth overview of coremap, pages table, etc. but the lecture content already does a very good job.
Debugging Tips
Multiple Entries in the TLB
This could be caused by 1 of 2 major reasons. The first of which is a programming error in which you could read an incorrect entry from your page table causing you to write the same entry to the TLB a second time.
A second reason could be that you forgot to to OR in the VALID bit in your TLB entry.
Asserts failing in subpage_kmalloc()
Check all of your programming. This is most likely cause by a double free! Check all of your logic. Try commenting out frees until your problem goes away. However if you comment out all the frees in your program and this does not fix the problem then it is obviously not a double free.
Another cause could be freeing the wrong memory and reusing it somewhere else. If this memory belongs to one of your kernel structures i.e. a page table or the core map, this could cause major problems and very confusing errors.
These were two time consuming errors so hopefully this will help. If you have any other problems that most importantly you can articulate well, I can try and help.
I have been told that people have commented but they do not seem to be appearing. Checked the spam inbox; nothing. So you are welcome to email me at dixon_171 at hotmail dot com. This is not a primary email so you can feel free to spam it I will just ignore it.
-FlounderingZ
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