Architecture specific initialization prior to processor structures initialization

xtoskrnl/ke/amd64/krnlinit.c

@@ -20,6 +20,21 @@ XTAPI
 VOID
 KepArchInitialize(VOID)
 {
+    /* Enable global paging support */
+    ArWriteControlRegister(4, ArReadControlRegister(4) | CR4_PGE);
+
+    /* Enable write-protection */
+    ArWriteControlRegister(0, ArReadControlRegister(0) | CR0_WP);
+
+    /* Set alignment mask */
+    ArWriteControlRegister(0, ArReadControlRegister(0) | CR0_AM);
+
+    /* Re-enable IDE interrupts */
+    HlIoPortOutByte(0x376, 0);
+    HlIoPortOutByte(0x3F6, 0);
+
+    /* Set system call extensions (SCE) flag in EFER MSR */
+    ArWriteModelSpecificRegister(X86_MSR_EFER, ArReadModelSpecificRegister(X86_MSR_EFER) | X86_MSR_EFER_SCE);
 }
 
 /**

xtoskrnl/ke/i686/krnlinit.c

@@ -20,6 +20,15 @@ XTAPI
 VOID
 KepArchInitialize(VOID)
 {
+    /* Clear EFLAGS register */
+    ArWriteEflagsRegister(0);
+
+    /* Enable write-protection */
+    ArWriteControlRegister(0, ArReadControlRegister(0) | CR0_WP);
+
+    /* Re-enable IDE interrupts */
+    HlIoPortOutByte(0x376, 0);
+    HlIoPortOutByte(0x3F6, 0);
 }
 
 /**

xtoskrnl/ke/krnlinit.c

@@ -49,12 +49,12 @@ KeStartXtSystem(IN PKERNEL_INITIALIZATION_BLOCK Parameters)
     /* Initialize kernel stacks */
     KepInitializeStack(Parameters);
 
-    /* Initialize boot CPU */
-    ArInitializeProcessor();
-
     /* Architecture specific initialization */
     KepArchInitialize();
 
+    /* Initialize boot CPU */
+    ArInitializeProcessor();
+
     /* Switch boot stack alligning it to 4 byte boundary */
     KepSwitchBootStack(KeInitializationBlock->KernelBootStack & ~0x3);
 }