From 11e6c2a34db0ea3cd26d8b4061ca1061d008af0d Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Sergiusz=20Baza=C5=84ski?= <q3k@q3k.org>
Date: Tue, 30 Oct 2012 13:21:40 +0100
Subject: [PATCH] Basic idea about virtual memory... Now we need a physical
 memory manager beforehand.

---
 Kernel/include/Tier1/CKernelML4.h | 24 ++++++++++++++++++++----
 Kernel/src/Tier1/CKernelML4.cpp   |  3 +++
 2 files changed, 23 insertions(+), 4 deletions(-)
 create mode 100644 Kernel/src/Tier1/CKernelML4.cpp

diff --git a/Kernel/include/Tier1/CKernelML4.h b/Kernel/include/Tier1/CKernelML4.h
index 3641012..2562d36 100644
--- a/Kernel/include/Tier1/CKernelML4.h
+++ b/Kernel/include/Tier1/CKernelML4.h
@@ -7,23 +7,39 @@ extern "C" {
 };
 
 // This is more-or less just a C++ wrapper for T_PAGING_ML4. For use for pure-kernel processes only
+// It implements the following address space, virtually:
+//
+//  name   |       start        |        end          |              mapping
+// -------- -------------------- --------------------- ------------------------------------------------------------------
+// LOWMEM  - 0x0000000000000000 - 0x0000000000100000 -> lower 1MiB of physical memory, common, fits in 1/2 of a Table
+// SCRATCH - 0xFFFFFFFF00000000 - 0xFFFFFFFF3FFFFFFF -> kernel scratch space & heap. 4GiB, common, fits in 1/1 of a Directory
+// STACK   - 0xFFFFFFFF40000000 - 0xFFFFFFFF4FFFFFFF -> kernel stack, unique per ML4, 256MiB, fits in 1/16 of a Directory,
+// TEXT    - 0xFFFFFFFF80000000 - 0xFFFFFFFF8xxxxxxx -> kernel code physical location, common, fits in x/16 of a Directory
+
 namespace cb {
     class CKernelML4 {
         private:
             // The paging direcotry structure
             T_PAGING_ML4 *m_Directory;
+            bool m_ShouldFreeML4;
 
             // allocator and destructor for segments
             void *(*m_SegmentAllocator)(u64);
             void (*m_SegmentDestructor)(void *);
+
+            // kernel stack segment physical memory
+            u64 m_StackStartPhysical;
+            u64 m_StackSize;
+
+            // static pointers to common areas
+            static T_PAGING_TAB *m_LOWMEM;
+            static T_PAGING_DIR *m_SCRATCH;
+            static T_PAGING_DIR *m_TEXT;
         public:
-            // Creates a new page directory for a kernel task, with new stack and other private segments
+            // Creates a new page directory for a kernel task, with new stack and other internal stuff
             // Allocator is a function pointer to an allocator to use, Destructor is the same but for
             // deallocation
             CKernelML4(void *(*Allocator)(u64), void (*Destructor)(void *));
-            // Creates a new page directory for a kernel task, with existing stack
-            // This constructor also makes the destructor not free anything.
-            CKernelML4(void *StackStart, u64 StackSize);
 
             // Destroys the structures and frees the segments, if needed
             ~CKernelML4(void);
diff --git a/Kernel/src/Tier1/CKernelML4.cpp b/Kernel/src/Tier1/CKernelML4.cpp
new file mode 100644
index 0000000..3256f76
--- /dev/null
+++ b/Kernel/src/Tier1/CKernelML4.cpp
@@ -0,0 +1,3 @@
+#include "Tier1/CKernelML4.h"
+
+using namespace cb;