krfkeith / coffee-os

Automatically exported from code.google.com/p/coffee-os
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Paging/Threading Stalled Temporarily #3

Closed GoogleCodeExporter closed 9 years ago

GoogleCodeExporter commented 9 years ago
The Paging/Threading code is suspended upon further review.
Aparently some devs at osdever and Mike all seem to point to one thing:

1) The code works as-is(with the assumption that C ports ok to Pascal).
2) The kernel is mapped somehow by magic to 4MB or 3GB pageDir entry.[solved]

3) These HobbyOS devs must be building a project for class and not an actual OS 
or solution to someone's BAD code problems in C.(as I am)

Fixing #2 causes the following:

This causes a GPF in QEMU with:
      'Access beyond END of RAM'

Triple faulting on the paging unit is caused by not properly mapping[copy the 
kernel to another address and marking space as KernelMode, Writable, and 
InUse.] the kernel to another location before transfering control back to the 
processor and enabling paging. 

Anything else is a problem with allocation between Heap, PMM, and Paging(VMM) 
units. These problems have been fixed.

This is a headache to fix to say the least. Apparently this was an issue with 
windows at some point. I have to dive further into Linus' kernelbase in C to 
work out a viable solution. In the meanwhile, these units are disabled, but 
should be fully functional. The logic is properly implemented.(I will adjust 
the tasking code upon further review(it just builds for the moment) DO NOT 
ATTEMPT to ALLOC/FREE beyond end of physical ram or emulated ram in the 
meanwhile. QEMU will crash if you attempt to do so.

Use FLAT PMM memory model and HEAP as needed for now. These units work ok.

--Jazz

Original issue reported on code.google.com by frazzled...@gmail.com on 6 Dec 2010 at 2:39

GoogleCodeExporter commented 9 years ago
Paging code is nearly here now and has been revised to not use Tim Robinson's 
GDT Trick.

Paging code works under VM conditions.
Threads not tested. Code is incomplete.
See latest upload for details.

Original comment by frazzled...@gmail.com on 29 Jan 2011 at 4:51

GoogleCodeExporter commented 9 years ago

Original comment by frazzled...@gmail.com on 29 Jan 2011 at 4:53