Changeset 2042

Timestamp:

04/03/09 19:03:56 (3 years ago)

Author:

mwhitworth

Message:

Don't map the first page of memory, to properly catch null pointer errors.

Files:

• Whitix/trunk/arch/i386/mm/virt.c (modified) (7 diffs)

Whitix/trunk/arch/i386/mm/virt.c

@@ -68 +68 @@
                 extern DWORD bootPageDirectory;
                 manager->pageDir = (DWORD*)(VA_TO_PA(&bootPageDirectory));
+                
+                VirtMemMapPage(0, 0, 0);
         }else{
                 manager->pageDir=(DWORD*)(PageAlloc()->physAddr);
@@ -202 +204 @@
         {
                 pageDir[virtEnt]=PageAlloc()->physAddr | perms | PAGE_RW;
+                
                 /* Zero out the whole page table */
                 ZeroMemory(&pageTable[virtEnt*1024], PAGE_SIZE);
-
+                
                 /* If in kernel memory space, map to all other page directories */
                 if (virtEnt >= 768)
@@ -210 +213 @@
                         ListForEachEntry(manager,&managerList,list)
                         {
+                                /* Avoid copying to the same page table entry */
+                                if ((DWORD)manager->pageDir == VirtToPhys((DWORD)pageDir))
+                                        break;
+                                        
                                 virtDir=(DWORD*)VirtAllocateTemp((DWORD)manager->pageDir);
-                                virtDir[virtEnt]=pageDir[virtEnt];
+                                virtDir[virtEnt] = pageDir[virtEnt];
                                 VirtUnmapPhysPage((DWORD)virtDir);
                         }
                 }
         }
-
+        
         pageTable[PGTABLE_ENT(virt)]=phys | perms;
         invlpg(virt);
-
+        
         IrqRestoreFlags(flags);
         return 0;
@@ -263 +270 @@
                 if (!(pageDir[PGDIR_ENT(i)]) || !(pageTable[PGTABLE_ENT(i)])) /* Definitely not used */
                 {
-                        VirtMemMapPage(i,page,perms);
+                        VirtMemMapPage(i, page, perms);
                         IrqRestoreFlags(flags);
                         return i;
@@ -348 +355 @@
                                 pageTable[PGTABLE_ENT(address)] &= ~(0xFFF);
                                 pageTable[PGTABLE_ENT(address)] |= protection;
-//                              KePrint("address = %#X\n", pageTable[PGTABLE_ENT(address)]);
                         }
                 }
@@ -386 +392 @@
                 if (!pageDir[PGDIR_ENT(i)] || !pageTable[PGTABLE_ENT(i)]) /* Definitely not used */
                 {
-                        VirtMemMapPage(i,phys,PAGE_PRESENT | PAGE_KERNEL | PAGE_RW);
+                        VirtMemMapPage(i, phys, PAGE_PRESENT | PAGE_KERNEL | PAGE_RW);
                         return i;
                 }
@@ -398 +404 @@
 void VirtShowFault(DWORD address,int error)
 {
-        KePrint("\nAddress = %#X (pageDir[%d] = %#X)",address,address >> 22,pageDir[address >> 22]);
+        KePrint("\nAddress = %#X (pageDir[%d] = %#X)",address, address >> 22, pageDir[address >> 22]);
 
         if (pageDir[address >> 22])