Design of the Kernel of Truth Memory System

Initialized in this order:

Kernel Heap

Initialized first.
Initially a fixed sized heap at a fixed location. 1 Page, at the page after the end of the kernel binary.
Later we will find a large enough region by parsing the multiboot memory map.
First fit block allocator where each the region metadata is a prefix of the allocation.
Not currently kept in sorted order, or in 'binned' lists (regions of < 32 words, 128 words, 512 words, 1 page, more than a page)
May later grow after virtual memory allocator is initialized.
Depends on: physical memory allocator (after it is initialized).
Currently tested.

Each process has its own page table structure.
Three levels: Page Directory Pointer Table, Page Directory, Page Table.
PDPT is allocated on kernel heap. Physical address calculated by subtraction.
All four slots in the PDPT are reserved at initialization time.
A cache of higher half virtual address pointers to the PDPT is kept in the page table structure.
All of the higher half PD are initialized and mapped into all process page tables at initialization time.
The kernel and kernel heap are mapped into higher half and thus their PDs are shared by all page tables.
PD are mapped using the physical allocator. If they are to be manipulated, they must first be mapped into the current page table.
PT are mapped using the physical allocator. If they are to be manipulated they must first be mapped into the current page table.
New process page tables get: new aligned PDPT, four new PDPT entries, and the higher half mapped (including kernel binary and kernel heap).
Depends on: kernel heap, physical memory allocator.

Used to keep track of the physical memory allocator, higher half memory allocator, and lower half memory allocators.
Initially a sorted linked list of [address, size] pairs. Not binned. Later may be an RB tree.
Data structure lives on the kernel heap.
Currently tested.

Uses the Region Allocator.
Initialized using the multiboot memory map.
Has the kernel's physical memory addresses, the kernel heap's bootstrap physical address, and the VGA buffer's physical address all pruned from its memory space.
Since this is shared among all processes it is protected by a singly spinlock.
Depends on: Kernel heap.

Uses the Region Allocator.
Has the kernel's virtual memory addresses, the kernel heap's bootstrap virtual address, and the VGA buffer's virtual address all pruned from its memory space.
Since this is shared among all processes it is protected by a singly spinlock.
Depends on: Kernel heap, physical memory allocator, PAE paging.