[SharpOS Developers] Map of what kernel looks like in memory

[Bruce M. <ill...@gm...>]

On Sun, Aug 3, 2008 at 9:53 PM, Zachary Gorden <dra...@gm...>wrote:

> I actually have a similar question, and this pertains to the current
> mapping of the kernel in memory.  Because we don't have anything like ntldr
> or freeldr, the kernel needs to manually set up its page tables first, kinda
> like how Linux does it.  If we're following convention, I'll need to remap
> all of the addresses to their appropriate location in the upper 2GB.
>
> So my question basically is, is there a current map of what the kernel
> looks like in memory?
>
>
This is material is definitely better suited for a separate thread, (which
I've taken care of). I'll answer with as much as I expect is true...

The kernel has no well-defined structure in memory. The AOT outputs things
in a specific order (undocumented, but with research it wouldn't be hard to
determine), into a brute-forced binary that GRUB loads into memory and then
lets us have our way with ourselves.

So without a custom loader, or some sort of hacked implementation in order
to work with another loader, we currently do not have support for this.
Frankly, I don't think you can setup page tables without having something
tied to an interrupt when paging is needed to be done - which brings us to
identifying and accessing disk space. Due to the nano-kernel-esque design we
are shooting for, (as far as modularity), I don't think this is an option
for us right now.