IT ACTUALLY WORKS NOW.
Why wasn't it working? Oh, because I was not setting already present page tables's permissions to user mode. Just a little bug. THAT I SPENT DAYS TRYING TO FIND
Anyways, it works now. Such a relief...
Yes, that's not completely-from-scratch.
But let's be honest, am I going to do everything from scratch? Probably not. I'm not making my own bootloader.
And making a proper smaller-than-4-KB allocator is not something I want to do.
Plus, liballoc works perfectly in this rewrite, seeing as the MM code actually works, instead of leaking all your poor memory
And liballoc_{lock, unlock} can be actually defined, since we have spinlocks here!
