Document TODO steps

nucleus/src/arch/aarch64/memory/README.md

@@ -9,3 +9,51 @@ a specific-size page.
 ----
 
 For more information please re-read.
+
+
+
+
+
+
+
+
+
+
+
+----
+
+# Plan
+1. MMU tables - because we need separate memspaces for kernel and userspace
+   1a. Allocate initial page tables
+   1b. Map over available RAM sensibly
+   1c. Create kernel's own mapping (TTBR_EL1)
+
+# What does the kernel MMU code support?
+* mapping
+* unmapping
+* switching per-process mappings (virtspaces)
+* virt2phys resolution
+* direct phys access for kernel (TTBR_EL1 mapping to physmem)
+* initial kernel memory allocation: for mapping tables and capnodes, for initial thread TCB and stacks
+
+# public api:
+    ARMMU invocations:
+        on page directory cap
+            cache maintenance (clean/invalidate/unify)
+        on page table cap
+            map
+            unmap
+        on small frame/frame caps
+            map
+            remap
+            unmap
+            cache maintenance (clean/invalidate/unify)
+            get address
+        on asid control cap
+        on asid pool cap
+
+
+# Minimum Required Functionality (build from this)
+* resolve VA to PA - resolving lets kernel access mapped process memory.
+  (start from the process' virtspace root - Page Directory)
+* flush page, pd, pt, virtspace - will be important for thread switching