Index: ntoskrnl/include/internal/i386/trap_x.h
===================================================================
--- ntoskrnl/include/internal/i386/trap_x.h	(revision 69220)
+++ ntoskrnl/include/internal/i386/trap_x.h	(working copy)
@@ -175,7 +175,7 @@
         CheckDr(1, Prcb->ProcessorState.SpecialRegisters.KernelDr1);
         CheckDr(2, Prcb->ProcessorState.SpecialRegisters.KernelDr2);
         CheckDr(3, Prcb->ProcessorState.SpecialRegisters.KernelDr3);
-        //CheckDr(7, Prcb->ProcessorState.SpecialRegisters.KernelDr7);
+        CheckDr(7, Prcb->ProcessorState.SpecialRegisters.KernelDr7);
     }
 
     StopChecking = FALSE;
Index: ntoskrnl/kdbg/kdb.c
===================================================================
--- ntoskrnl/kdbg/kdb.c	(revision 69220)
+++ ntoskrnl/kdbg/kdb.c	(working copy)
@@ -136,7 +136,7 @@
     PKTRAP_FRAME TrapFrame,
     PKDB_KTRAP_FRAME KdbTrapFrame)
 {
-    ULONG TrapCr0, TrapCr2, TrapCr3, TrapCr4;
+    PKPRCB Prcb;
 
     /* Copy the TrapFrame only up to Eflags and zero the rest*/
     RtlCopyMemory(&KdbTrapFrame->Tf, TrapFrame, FIELD_OFFSET(KTRAP_FRAME, HardwareEsp));
@@ -143,36 +143,35 @@
     RtlZeroMemory((PVOID)((ULONG_PTR)&KdbTrapFrame->Tf + FIELD_OFFSET(KTRAP_FRAME, HardwareEsp)),
                   sizeof(KTRAP_FRAME) - FIELD_OFFSET(KTRAP_FRAME, HardwareEsp));
 
-#ifndef _MSC_VER
-   asm volatile(
-      "movl %%cr0, %0"    "\n\t"
-      "movl %%cr2, %1"    "\n\t"
-      "movl %%cr3, %2"    "\n\t"
-      "movl %%cr4, %3"    "\n\t"
-      : "=r"(TrapCr0), "=r"(TrapCr2),
-        "=r"(TrapCr3), "=r"(TrapCr4));
-#else
-   __asm
-   {
-       mov eax, cr0;
-       mov TrapCr0, eax;
 
-       mov eax, cr2;
-       mov TrapCr2, eax;
 
-       mov eax, cr3;
-       mov TrapCr3, eax;
-/* FIXME: What's the problem with cr4? */
-       //mov eax, cr4;
-       //mov TrapCr4, eax;
-   }
-#endif
+    /* Get CR0, CR2 and CR3 */
+    KdbTrapFrame->Cr0 = __readcr0();
+    KdbTrapFrame->Cr2 = __readcr2();
+    KdbTrapFrame->Cr3 = __readcr3();
 
-    KdbTrapFrame->Cr0 = TrapCr0;
-    KdbTrapFrame->Cr2 = TrapCr2;
-    KdbTrapFrame->Cr3 = TrapCr3;
-    KdbTrapFrame->Cr4 = TrapCr4;
+    /* Check if CR4 exists */
+    if (KeFeatureBits & KF_CR4)
+    {
+        /* Get it */
+        KdbTrapFrame->Cr4 = __readcr4();
+    }
+    else
+    {
+        /* Just clear it */
+        KdbTrapFrame->Cr4 = 0;
+    }
 
+    /* Save current debug registers for kernel */
+    Prcb = KeGetCurrentPrcb();
+    Prcb->ProcessorState.SpecialRegisters.KernelDr0 = __readdr(0);
+    Prcb->ProcessorState.SpecialRegisters.KernelDr1 = __readdr(1);
+    Prcb->ProcessorState.SpecialRegisters.KernelDr2 = __readdr(2);
+    Prcb->ProcessorState.SpecialRegisters.KernelDr3 = __readdr(3);
+    Prcb->ProcessorState.SpecialRegisters.KernelDr6 = __readdr(6);
+    Prcb->ProcessorState.SpecialRegisters.KernelDr7 = __readdr(7);
+
+    /* Get SS and Stack */
     KdbTrapFrame->Tf.HardwareEsp = KiEspFromTrapFrame(TrapFrame);
     KdbTrapFrame->Tf.HardwareSegSs = (USHORT)(KiSsFromTrapFrame(TrapFrame) & 0xFFFF);
 
@@ -185,11 +184,23 @@
     PKDB_KTRAP_FRAME KdbTrapFrame,
     PKTRAP_FRAME TrapFrame)
 {
+    PKPRCB Prcb;
+
     /* Copy the TrapFrame only up to Eflags and zero the rest*/
     RtlCopyMemory(TrapFrame, &KdbTrapFrame->Tf, FIELD_OFFSET(KTRAP_FRAME, HardwareEsp));
 
     /* FIXME: write cr0, cr2, cr3 and cr4 (not needed atm) */
 
+    /* We may have altered debug registers, update PRCB */
+    Prcb = KeGetCurrentPrcb();
+    Prcb->ProcessorState.SpecialRegisters.KernelDr0 = TrapFrame->Dr0;
+    Prcb->ProcessorState.SpecialRegisters.KernelDr1 = TrapFrame->Dr1;
+    Prcb->ProcessorState.SpecialRegisters.KernelDr2 = TrapFrame->Dr2;
+    Prcb->ProcessorState.SpecialRegisters.KernelDr3 = TrapFrame->Dr3;
+    Prcb->ProcessorState.SpecialRegisters.KernelDr6 = TrapFrame->Dr6;
+    Prcb->ProcessorState.SpecialRegisters.KernelDr7 = TrapFrame->Dr7;
+
+    /* Save SS and Stack */
     KiSsToTrapFrame(TrapFrame, KdbTrapFrame->Tf.HardwareSegSs);
     KiEspToTrapFrame(TrapFrame, KdbTrapFrame->Tf.HardwareEsp);
 
@@ -1405,7 +1416,7 @@
                                                      BreakPoint->Data.SavedInstruction, NULL)))
             {
                 KdbpPrint("Couldn't restore original instruction after INT3! Cannot continue execution.\n");
-                KeBugCheck(0); // FIXME: Proper bugcode!
+                for (;;);
             }
         }
 
@@ -1687,7 +1698,7 @@
 
 continue_execution:
     /* Clear debug status */
-    if (ExceptionCode == STATUS_BREAKPOINT) /* FIXME: Why clear DR6 on INT3? */
+    if (ExceptionCode == STATUS_BREAKPOINT)
     {
         /* Set the RF flag so we don't trigger the same breakpoint again. */
         if (Resume)
@@ -1695,9 +1706,6 @@
             TrapFrame->EFlags |= EFLAGS_RF;
         }
 
-        /* Clear dr6 status flags. */
-        TrapFrame->Dr6 &= ~0x0000e00f;
-
         if (!(KdbEnteredOnSingleStep && KdbSingleStepOver))
         {
             /* Skip the current instruction */