From 334e1bbae579effd878fc44ddd13f20d28516ca5 Mon Sep 17 00:00:00 2001
From: Adrien Bourmault <neox@os-k.eu>
Date: Thu, 9 Jan 2020 22:34:38 +0100
Subject: [PATCH] New dynamic paging implementation (3) #67

---
 kaleid/kernel/mm/paging.c | 88 +++++++++++++++++++++++----------------
 1 file changed, 52 insertions(+), 36 deletions(-)

diff --git a/kaleid/kernel/mm/paging.c b/kaleid/kernel/mm/paging.c
index d3265e5..653ffb9 100644
--- a/kaleid/kernel/mm/paging.c
+++ b/kaleid/kernel/mm/paging.c
@@ -36,6 +36,8 @@ enum
     NX           = 1UL << 63
 };
 
+//-----------
+
 //
 // Creates our new page table structure and loads it
 //
@@ -177,26 +179,38 @@ void MmInitPaging(void)
     DebugLog("\tPage table size : %u MB\n", (lastDirectoryAddr - firstDirectoryAddr)/MB);
 }
 
+//
+// Get a page from an address
+//
+static pte_t MmGetPageDescriptor(void *virtualAddr)
+{
+    ulong virtAddrPage = (ulong)virtualAddr & ( ~(KPAGESIZE - 1));
+
+    if (virtAddrPage > MmVirtLastAddress) {
+        KeStartPanic("MmSetPage() Out of bound of the address space !");
+    }
+
+    pdpe_t *pdp = (pdpe_t*)((ulong)MmPageMapLevel4[(virtAddrPage / ((ulong)KPAGESIZE * 0x8000000)) % 512] & ~(KPAGESIZE - 1));
+    //DebugLog("pdp\t: %p\n", pdp);
+    pde_t *pd = (pde_t*)( (ulong)pdp[(virtAddrPage / ((ulong)KPAGESIZE * 0x40000)) % 512] & ~(KPAGESIZE - 1));
+    //DebugLog("pd\t: %p\n", pd);
+    pte_t *pt = (pte_t*)( (ulong)pd[(virtAddrPage / ((ulong)KPAGESIZE * 0x200)) % 512] & ~(KPAGESIZE - 1));
+    //DebugLog("pt\t: %p\n", pt);
+
+    ulong page = (ulong)pt[(virtAddrPage / ((ulong)KPAGESIZE)) % 512];
+    //DebugLog("page (with flags): %p\n", page);
+
+    return page;
+}
+
+
 //
 // Translates a virtual address to its physical equivalent
 //
 void *MmTransVirtToPhyAddr(void* virtualAddr)
 {
     ulong virtAddrPage = (ulong)virtualAddr & ( ~(KPAGESIZE - 1));
-
-    if (virtAddrPage > MmVirtLastAddress) {
-        KeStartPanic("MmTransVirtToPhyAddr() Out of bound of the address space !");
-    }
-
-    pdpe_t *pdp = (pdpe_t*)((ulong)MmPageMapLevel4[(virtAddrPage / ((ulong)KPAGESIZE * 0x8000000)) % 512] & ~(KPAGESIZE - 1));
-    DebugLog("pdp\t: %p\n", pdp);
-    pde_t *pd = (pde_t*)( (ulong)pdp[(virtAddrPage / ((ulong)KPAGESIZE * 0x40000)) % 512] & ~(KPAGESIZE - 1));
-    DebugLog("pd\t: %p\n", pd);
-    pte_t *pt = (pte_t*)( (ulong)pd[(virtAddrPage / ((ulong)KPAGESIZE * 0x200)) % 512] & ~(KPAGESIZE - 1));
-    DebugLog("pt\t: %p\n", pt);
-
-    ulong page = (ulong)pt[(virtAddrPage / ((ulong)KPAGESIZE)) % 512];
-    DebugLog("page (with flags): %p\n", page);
+    pte_t page = MmGetPageDescriptor(virtualAddr);
 
     if (page == (page & ~(KPAGESIZE - 1))) {
         return NULL;
@@ -215,19 +229,11 @@ void *MmTransPhyToVirtAddr(void* physicalAddr)
 //
 void MmSetPage(void* virtualAddr, ulong flags)
 {
-    ulong virtAddrPage = (ulong)virtualAddr & ( ~(KPAGESIZE - 1));
+    pte_t page = MmGetPageDescriptor(virtualAddr);
 
-    if (virtAddrPage > MmVirtLastAddress) {
-        KeStartPanic("MmSetPage() Out of bound of the address space !");
-    }
+    page |= flags;
 
-    pdpe_t *pdp = (pdpe_t*)((ulong)MmPageMapLevel4[virtAddrPage / ((ulong)KPAGESIZE * 0x8000000)] & ~(KPAGESIZE - 1));
-    pde_t *pd = (pde_t*)( (ulong)pdp[virtAddrPage / ((ulong)KPAGESIZE * 0x40000)] & ~(KPAGESIZE - 1));
-    pte_t *pt = (pte_t*)( (ulong)pd[virtAddrPage / ((ulong)KPAGESIZE * 0x200)] & ~(KPAGESIZE - 1));
-
-    pt[virtAddrPage / ((ulong)KPAGESIZE)] |= flags;
-
-    KeFlushTlbSingle(virtAddrPage);
+    KeFlushTlbSingle(page);
 }
 
 //
@@ -235,21 +241,31 @@ void MmSetPage(void* virtualAddr, ulong flags)
 //
 void MmUnsetPage(void* virtualAddr, ulong flags)
 {
-    ulong virtAddrPage = (ulong)virtualAddr & ( ~(KPAGESIZE - 1));
+    pte_t page = MmGetPageDescriptor(virtualAddr);
 
-    if (virtAddrPage > MmVirtLastAddress) {
-        KeStartPanic("MmUnsetPage() Out of bound of the address space !");
-    }
+    page &= (~flags);
 
-    pdpe_t *pdp = (pdpe_t*)((ulong)MmPageMapLevel4[virtAddrPage / ((ulong)KPAGESIZE * 0x8000000)] & ~(KPAGESIZE - 1));
-    pde_t *pd = (pde_t*)( (ulong)pdp[virtAddrPage / ((ulong)KPAGESIZE * 0x40000)] & ~(KPAGESIZE - 1));
-    pte_t *pt = (pte_t*)( (ulong)pd[virtAddrPage / ((ulong)KPAGESIZE * 0x200)] & ~(KPAGESIZE - 1));
-
-    pt[virtAddrPage / ((ulong)KPAGESIZE)] &= (~flags);
-
-    KeFlushTlbSingle(virtAddrPage);
+    KeFlushTlbSingle(page);
 }
 
+//
+// Map a page in memory
+//
+void MmMapPage(void* virtualAddr, void* physicalAddr, ulong flags)
+{
+
+}
+
+//
+// Unmap a page in memory
+//
+void MmUnmapPage(void* virtualAddr)
+{
+
+}
+
+//-----------
+
 //
 // Returns the rank of the Stack Guards
 //