- NDK 0.98, now with versionned headers. Too many changes to list, see the TinyKRNL...
[reactos.git] / reactos / ntoskrnl / ke / i386 / exp.c
index 429db8c..27db6a3 100644 (file)
@@ -1,39 +1,41 @@
 /*
- *  ReactOS kernel
- *  Copyright (C) 1998, 1999, 2000, 2001 ReactOS Team
- *
- *  This program is free software; you can redistribute it and/or modify
- *  it under the terms of the GNU General Public License as published by
- *  the Free Software Foundation; either version 2 of the License, or
- *  (at your option) any later version.
- *
- *  This program is distributed in the hope that it will be useful,
- *  but WITHOUT ANY WARRANTY; without even the implied warranty of
- *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- *  GNU General Public License for more details.
- *
- *  You should have received a copy of the GNU General Public License
- *  along with this program; if not, write to the Free Software
- *  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ * COPYRIGHT:       See COPYING in the top level directory
+ * PROJECT:         ReactOS Kernel
+ * FILE:            ntoskrnl/ke/i386/exp.c
+ * PURPOSE:         Exception Support Code
+ * PROGRAMMERS:     Alex Ionescu (alex@relsoft.net)
+ *                  Gregor Anich
+ *                  David Welch (welch@cwcom.net)
+ *                  Skywing (skywing@valhallalegends.com)
  */
+
 /*
- * PROJECT:              ReactOS kernel
- * FILE:                 ntoskrnl/ke/i386/exp.c
- * PURPOSE:              Handling exceptions
- * PROGRAMMERS:          David Welch (welch@cwcom.net)
- *                       Skywing (skywing@valhallalegends.com)
- * REVISION HISTORY:
- *              ??/??/??: Created
- *              09/12/03: KeRaiseUserException added (Skywing).
+ * FIXMES:
+ *  - Clean up file (remove all stack functions and use RtlWalkFrameChain/RtlCaptureStackBacktrace)
+ *  - Sanitize some context fields.
+ *  - Add PSEH handler when an exception occurs in an exception (KiCopyExceptionRecord).
+ *  - Forward exceptions to user-mode debugger.
  */
 
 /* INCLUDES *****************************************************************/
 
 #include <ntoskrnl.h>
-#include <pseh.h>
+
 #define NDEBUG
 #include <internal/debug.h>
 
+#if defined (ALLOC_PRAGMA)
+#pragma alloc_text(INIT, KeInitExceptions)
+#endif
+
+VOID
+NTAPI
+Ki386AdjustEsp0(
+    IN PKTRAP_FRAME TrapFrame
+);
+
+extern KIDTENTRY KiIdt[];
+
 /* GLOBALS *****************************************************************/
 
 #define FLAG_IF (1<<9)
 # define ARRAY_SIZE(x) (sizeof (x) / sizeof (x[0]))
 #endif
 
-extern void interrupt_handler2e(void);
-extern void interrupt_handler2d(void);
-
-extern VOID KiTrap0(VOID);
-extern VOID KiTrap1(VOID);
-extern VOID KiTrap2(VOID);
-extern VOID KiTrap3(VOID);
-extern VOID KiTrap4(VOID);
-extern VOID KiTrap5(VOID);
-extern VOID KiTrap6(VOID);
-extern VOID KiTrap7(VOID);
-extern VOID KiTrap8(VOID);
-extern VOID KiTrap9(VOID);
-extern VOID KiTrap10(VOID);
-extern VOID KiTrap11(VOID);
-extern VOID KiTrap12(VOID);
-extern VOID KiTrap13(VOID);
-extern VOID KiTrap14(VOID);
-extern VOID KiTrap15(VOID);
-extern VOID KiTrap16(VOID);
-extern VOID KiTrap17(VOID);
-extern VOID KiTrap18(VOID);
-extern VOID KiTrap19(VOID);
-extern VOID KiTrapUnknown(VOID);
-
 extern ULONG init_stack;
 extern ULONG init_stack_top;
 
@@ -99,7 +76,7 @@ static char *ExceptionTypeStrings[] =
     "SIMD Fault"
   };
 
-static NTSTATUS ExceptionToNtStatus[] =
+NTSTATUS ExceptionToNtStatus[] =
   {
     STATUS_INTEGER_DIVIDE_BY_ZERO,
     STATUS_SINGLE_STEP,
@@ -108,7 +85,7 @@ static NTSTATUS ExceptionToNtStatus[] =
     STATUS_INTEGER_OVERFLOW,
     STATUS_ARRAY_BOUNDS_EXCEEDED,
     STATUS_ILLEGAL_INSTRUCTION,
-    STATUS_ACCESS_VIOLATION, /* STATUS_FLT_INVALID_OPERATION */
+    STATUS_FLOAT_INVALID_OPERATION,
     STATUS_ACCESS_VIOLATION,
     STATUS_ACCESS_VIOLATION,
     STATUS_ACCESS_VIOLATION,
@@ -117,49 +94,47 @@ static NTSTATUS ExceptionToNtStatus[] =
     STATUS_ACCESS_VIOLATION,
     STATUS_ACCESS_VIOLATION,
     STATUS_ACCESS_VIOLATION, /* RESERVED */
-    STATUS_ACCESS_VIOLATION, /* STATUS_FLT_INVALID_OPERATION */
+    STATUS_FLOAT_INVALID_OPERATION, /* Should not be used, the FPU can give more specific info */
     STATUS_DATATYPE_MISALIGNMENT,
     STATUS_ACCESS_VIOLATION,
-    STATUS_ACCESS_VIOLATION  /* STATUS_FLT_MULTIPLE_TRAPS? */
+    STATUS_FLOAT_MULTIPLE_TRAPS,
   };
 
 /* FUNCTIONS ****************************************************************/
 
-#if defined(DBG) || defined(KDBG)
-BOOLEAN STDCALL
-KeRosPrintAddress(PVOID address)
-{
-  return KdbSymPrintAddress(address);
-}
-#else /* KDBG */
 BOOLEAN STDCALL
-KeRosPrintAddress(PVOID address)
+KiRosPrintAddress(PVOID address)
 {
    PLIST_ENTRY current_entry;
-   MODULE_TEXT_SECTION* current;
-   extern LIST_ENTRY ModuleTextListHead;
+   PLDR_DATA_TABLE_ENTRY current;
+   extern LIST_ENTRY ModuleListHead;
    ULONG_PTR RelativeAddress;
+   ULONG i = 0;
 
-   current_entry = ModuleTextListHead.Flink;
-
-   while (current_entry != &ModuleTextListHead &&
-         current_entry != NULL)
-     {
-       current =
-         CONTAINING_RECORD(current_entry, MODULE_TEXT_SECTION, ListEntry);
+   do
+   {
+     current_entry = ModuleListHead.Flink;
+
+     while (current_entry != &ModuleListHead)
+       {
+          current =
+            CONTAINING_RECORD(current_entry, LDR_DATA_TABLE_ENTRY, InLoadOrderLinks);
+
+          if (address >= (PVOID)current->DllBase &&
+              address < (PVOID)((ULONG_PTR)current->DllBase + current->SizeOfImage))
+            {
+              RelativeAddress = (ULONG_PTR) address - (ULONG_PTR) current->DllBase;
+              DbgPrint("<%wZ: %x>", &current->FullDllName, RelativeAddress);
+              return(TRUE);
+            }
+          current_entry = current_entry->Flink;
+       }
+
+     address = (PVOID)((ULONG_PTR)address & ~(ULONG_PTR)MmSystemRangeStart);
+   } while(++i <= 1);
 
-       if (address >= (PVOID)current->Base &&
-           address < (PVOID)(current->Base + current->Length))
-         {
-            RelativeAddress = (ULONG_PTR) address - current->Base;
-           DbgPrint("<%ws: %x>", current->Name, RelativeAddress);
-           return(TRUE);
-         }
-       current_entry = current_entry->Flink;
-     }
    return(FALSE);
 }
-#endif /* KDBG */
 
 ULONG
 KiKernelTrapHandler(PKTRAP_FRAME Tf, ULONG ExceptionNr, PVOID Cr2)
@@ -174,7 +149,7 @@ KiKernelTrapHandler(PKTRAP_FRAME Tf, ULONG ExceptionNr, PVOID Cr2)
     {
       Er.ExceptionCode = STATUS_ACCESS_VIOLATION;
       Er.NumberParameters = 2;
-      Er.ExceptionInformation[0] = Tf->ErrorCode & 0x1;
+      Er.ExceptionInformation[0] = Tf->ErrCode & 0x1;
       Er.ExceptionInformation[1] = (ULONG)Cr2;
     }
   else
@@ -190,18 +165,18 @@ KiKernelTrapHandler(PKTRAP_FRAME Tf, ULONG ExceptionNr, PVOID Cr2)
       Er.NumberParameters = 0;
     }
 
-  Er.ExceptionFlags = ((NTSTATUS) STATUS_SINGLE_STEP == (NTSTATUS) Er.ExceptionCode
-    || (NTSTATUS) STATUS_BREAKPOINT == (NTSTATUS) Er.ExceptionCode) ?
-    EXCEPTION_NONCONTINUABLE : 0;
+  /* FIXME: Which exceptions are noncontinuable? */
+  Er.ExceptionFlags = 0;
 
-  KiDispatchException(&Er, 0, Tf, KernelMode, TRUE);
+  KiDispatchException(&Er, NULL, Tf, KernelMode, TRUE);
 
   return(0);
 }
 
-ULONG
+VOID
 KiDoubleFaultHandler(VOID)
 {
+#if 0
   unsigned int cr2;
   ULONG StackLimit;
   ULONG StackBase;
@@ -220,7 +195,7 @@ KiDoubleFaultHandler(VOID)
 #endif
 
   OldTss = KeGetCurrentKPCR()->TSS;
-  Esp0 = OldTss->Esp;
+  Esp0 = OldTss->Esp0;
 
   /* Get CR2 */
   cr2 = Ke386GetCr2();
@@ -266,7 +241,7 @@ KiDoubleFaultHandler(VOID)
    if (PsGetCurrentProcess() != NULL)
      {
        DbgPrint("Pid: %x <", PsGetCurrentProcess()->UniqueProcessId);
-       DbgPrint("%.8s> ", PsGetCurrentProcess()->ImageFileName);
+       DbgPrint("%.16s> ", PsGetCurrentProcess()->ImageFileName);
      }
    if (PsGetCurrentThread() != NULL)
      {
@@ -279,10 +254,10 @@ KiDoubleFaultHandler(VOID)
            OldTss->Fs, OldTss->Gs);
    DbgPrint("EAX: %.8x   EBX: %.8x   ECX: %.8x\n", OldTss->Eax, OldTss->Ebx,
            OldTss->Ecx);
-   DbgPrint("EDX: %.8x   EBP: %.8x   ESI: %.8x\n   ESP: %.8x", OldTss->Edx,
+   DbgPrint("EDX: %.8x   EBP: %.8x   ESI: %.8x\nESP: %.8x ", OldTss->Edx,
            OldTss->Ebp, OldTss->Esi, Esp0);
    DbgPrint("EDI: %.8x   EFLAGS: %.8x ", OldTss->Edi, OldTss->Eflags);
-   if (OldTss->Cs == KERNEL_CS)
+   if (OldTss->Cs == KGDT_R0_CODE)
      {
        DbgPrint("kESP %.8x ", Esp0);
        if (PsGetCurrentThread() != NULL)
@@ -296,7 +271,7 @@ KiDoubleFaultHandler(VOID)
      {
        DbgPrint("User ESP %.8x\n", OldTss->Esp);
      }
-  if ((OldTss->Cs & 0xffff) == KERNEL_CS)
+  if ((OldTss->Cs & 0xffff) == KGDT_R0_CODE)
     {
       if (PsGetCurrentThread() != NULL)
        {
@@ -305,8 +280,8 @@ KiDoubleFaultHandler(VOID)
        }
       else
        {
-         StackLimit = (ULONG)&init_stack_top;
-         StackBase = (ULONG)&init_stack;
+         StackLimit = (ULONG)init_stack_top;
+         StackBase = (ULONG)init_stack;
        }
 
       /*
@@ -320,7 +295,7 @@ KiDoubleFaultHandler(VOID)
        {
          KeRosPrintAddress((PVOID)Frame[1]);
          Frame = (PULONG)Frame[0];
-          DbgPrint(" ");
+          DbgPrint("\n");
        }
 #else
       DbgPrint("Frames: ");
@@ -390,8 +365,8 @@ KiDoubleFaultHandler(VOID)
              DbgPrint("{");
              if (StackRepeatLength[i] == 0)
                {
-                 for(;;);
-               }
+   for(;;);
+}
              for (j = 0; j < StackRepeatLength[i]; j++)
                {
                  KeRosPrintAddress(StackTrace[i + j]);
@@ -402,22 +377,20 @@ KiDoubleFaultHandler(VOID)
        }
 #endif
     }
-
+#endif
    DbgPrint("\n");
    for(;;);
-   return 0;
 }
 
 VOID
+NTAPI
 KiDumpTrapFrame(PKTRAP_FRAME Tf, ULONG Parameter1, ULONG Parameter2)
 {
   ULONG cr3_;
-  ULONG i;
   ULONG StackLimit;
-  PULONG Frame;
   ULONG Esp0;
-  ULONG ExceptionNr = (ULONG)Tf->DebugArgMark;
-  ULONG cr2 = (ULONG)Tf->DebugPointer;
+  ULONG ExceptionNr = (ULONG)Tf->DbgArgMark;
+  ULONG cr2 = (ULONG)Tf->DbgArgPointer;
 
   Esp0 = (ULONG)Tf;
 
@@ -427,14 +400,14 @@ KiDumpTrapFrame(PKTRAP_FRAME Tf, ULONG Parameter1, ULONG Parameter2)
    if (ExceptionNr < ARRAY_SIZE(ExceptionTypeStrings))
      {
        DbgPrint("%s Exception: %d(%x)\n", ExceptionTypeStrings[ExceptionNr],
-                ExceptionNr, Tf->ErrorCode&0xffff);
+                ExceptionNr, Tf->ErrCode&0xffff);
      }
    else
      {
-       DbgPrint("Exception: %d(%x)\n", ExceptionNr, Tf->ErrorCode&0xffff);
+       DbgPrint("Exception: %d(%x)\n", ExceptionNr, Tf->ErrCode&0xffff);
      }
    DbgPrint("Processor: %d CS:EIP %x:%x ", KeGetCurrentProcessorNumber(),
-           Tf->Cs&0xffff, Tf->Eip);
+           Tf->SegCs&0xffff, Tf->Eip);
    KeRosPrintAddress((PVOID)Tf->Eip);
    DbgPrint("\n");
    Ke386GetPageTableDirectory(cr3_);
@@ -443,7 +416,7 @@ KiDumpTrapFrame(PKTRAP_FRAME Tf, ULONG Parameter1, ULONG Parameter2)
    if (PsGetCurrentProcess() != NULL)
      {
        DbgPrint("Pid: %x <", PsGetCurrentProcess()->UniqueProcessId);
-       DbgPrint("%.8s> ", PsGetCurrentProcess()->ImageFileName);
+       DbgPrint("%.16s> ", PsGetCurrentProcess()->ImageFileName);
      }
    if (PsGetCurrentThread() != NULL)
      {
@@ -452,13 +425,13 @@ KiDumpTrapFrame(PKTRAP_FRAME Tf, ULONG Parameter1, ULONG Parameter2)
                 PsGetCurrentThread()->Cid.UniqueThread);
      }
    DbgPrint("\n");
-   DbgPrint("DS %x ES %x FS %x GS %x\n", Tf->Ds&0xffff, Tf->Es&0xffff,
-           Tf->Fs&0xffff, Tf->Gs&0xfff);
+   DbgPrint("DS %x ES %x FS %x GS %x\n", Tf->SegDs&0xffff, Tf->SegEs&0xffff,
+           Tf->SegFs&0xffff, Tf->SegGs&0xfff);
    DbgPrint("EAX: %.8x   EBX: %.8x   ECX: %.8x\n", Tf->Eax, Tf->Ebx, Tf->Ecx);
    DbgPrint("EDX: %.8x   EBP: %.8x   ESI: %.8x   ESP: %.8x\n", Tf->Edx,
            Tf->Ebp, Tf->Esi, Esp0);
-   DbgPrint("EDI: %.8x   EFLAGS: %.8x ", Tf->Edi, Tf->Eflags);
-   if ((Tf->Cs&0xffff) == KERNEL_CS)
+   DbgPrint("EDI: %.8x   EFLAGS: %.8x ", Tf->Edi, Tf->EFlags);
+   if ((Tf->SegCs&0xffff) == KGDT_R0_CODE)
      {
        DbgPrint("kESP %.8x ", Esp0);
        if (PsGetCurrentThread() != NULL)
@@ -475,52 +448,13 @@ KiDumpTrapFrame(PKTRAP_FRAME Tf, ULONG Parameter1, ULONG Parameter2)
      }
    else
      {
-       StackLimit = (ULONG)&init_stack_top;
+       StackLimit = (ULONG)init_stack_top;
      }
 
    /*
     * Dump the stack frames
     */
-   DbgPrint("Frames: ");
-   /* Change to an #if 0 if no frames are printed because of fpo. */
-#if 1
-   i = 1;
-   Frame = (PULONG)Tf->Ebp;
-   while (Frame != NULL)
-     {
-       NTSTATUS Status;
-       PVOID Eip;
-       Status = MmSafeCopyFromUser(&Eip, Frame + 1, sizeof(Eip));
-       if (!NT_SUCCESS(Status))
-        {
-          DbgPrint("<INVALID>");
-          break;
-        }
-       if (!KeRosPrintAddress(Eip))
-        {
-          DbgPrint("<%X>", Eip);
-        }
-       Status = MmSafeCopyFromUser(&Frame, Frame, sizeof(Frame));
-       if (!NT_SUCCESS(Status))
-        {
-          break;
-        }
-       i++;
-       DbgPrint(" ");
-     }
-#else
-   i = 1;
-   Frame = (PULONG)((ULONG_PTR)Esp0 + KTRAP_FRAME_EFLAGS);
-   while (Frame < (PULONG)PsGetCurrentThread()->Tcb.StackBase && i < 50)
-     {
-        ULONG Address = *Frame;
-        if (KeRosPrintAddress((PVOID)Address))
-          {
-            i++;
-          }
-        Frame++;
-     }
-#endif
+   KeDumpStackFrames((PULONG)Tf->Ebp);
 }
 
 ULONG
@@ -532,30 +466,25 @@ KiTrapHandler(PKTRAP_FRAME Tf, ULONG ExceptionNr)
  *        Complete CPU context
  */
 {
-   unsigned int cr2;
+   ULONG_PTR cr2;
    NTSTATUS Status;
    ULONG Esp0;
 
-   /* Store the exception number in an unused field in the trap frame. */
-   Tf->DebugArgMark = (PVOID)ExceptionNr;
+   ASSERT(ExceptionNr != 14);
 
    /* Use the address of the trap frame as approximation to the ring0 esp */
    Esp0 = (ULONG)&Tf->Eip;
 
    /* Get CR2 */
    cr2 = Ke386GetCr2();
-   Tf->DebugPointer = (PVOID)cr2;
-
-   if (ExceptionNr == 14 && Tf->Eflags & FLAG_IF)
-   {
-     Ke386EnableInterrupts();
-   }
+   Tf->DbgArgPointer = cr2;
 
    /*
     * If this was a V86 mode exception then handle it specially
     */
-   if (Tf->Eflags & (1 << 17))
+   if (Tf->EFlags & (1 << 17))
      {
+       DPRINT("Tf->Eflags, %x, Tf->Eip %x, ExceptionNr: %d\n", Tf->EFlags, Tf->Eip, ExceptionNr);
        return(KeV86Exception(ExceptionNr, Tf, cr2));
      }
 
@@ -565,29 +494,23 @@ KiTrapHandler(PKTRAP_FRAME Tf, ULONG ExceptionNr)
    if (PsGetCurrentThread() != NULL &&
        Esp0 < (ULONG)PsGetCurrentThread()->Tcb.StackLimit)
      {
-       DbgPrint("Stack underflow (tf->esp %x Limit %x)\n",
-                Esp0, (ULONG)PsGetCurrentThread()->Tcb.StackLimit);
+       DPRINT1("Stack underflow (tf->esp %x Limit %x Eip %x)\n",
+               Esp0, (ULONG)PsGetCurrentThread()->Tcb.StackLimit, Tf->Eip);
        ExceptionNr = 12;
      }
 
-   /*
-    * Maybe handle the page fault and return
-    */
-   if (ExceptionNr == 14)
+   if (ExceptionNr == 15)
      {
-        if (Ke386NoExecute && Tf->ErrorCode & 0x10 && cr2 >= KERNEL_BASE)
-       {
-           KEBUGCHECKWITHTF(ATTEMPTED_EXECUTE_OF_NOEXECUTE_MEMORY, 0, 0, 0, 0, Tf);
-       }
-       Status = MmPageFault(Tf->Cs&0xffff,
-                            &Tf->Eip,
-                            &Tf->Eax,
-                            cr2,
-                            Tf->ErrorCode);
-       if (NT_SUCCESS(Status))
-         {
-            return(0);
-         }
+       /*
+        * FIXME:
+        *   This exception should never occur. The P6 has a bug, which does sometimes deliver
+        *   the apic spurious interrupt as exception 15. On an athlon64, I get one exception
+        *   in the early boot phase in apic mode (using the smp build). I've looked to the linux
+        *   sources. Linux does ignore this exception.
+        *
+        */
+       DPRINT1("Ignoring P6 Local APIC Spurious Interrupt Bug...\n");
+       return(0);
      }
 
    /*
@@ -617,7 +540,7 @@ KiTrapHandler(PKTRAP_FRAME Tf, ULONG ExceptionNr)
    /*
     * Handle user exceptions differently
     */
-   if ((Tf->Cs & 0xFFFF) == USER_CS)
+   if ((Tf->SegCs & 0xFFFF) == (KGDT_R3_CODE | RPL_MASK))
      {
        return(KiUserTrapHandler(Tf, ExceptionNr, (PVOID)cr2));
      }
@@ -627,21 +550,487 @@ KiTrapHandler(PKTRAP_FRAME Tf, ULONG ExceptionNr)
     }
 }
 
+ULONG
+NTAPI
+KiEspFromTrapFrame(IN PKTRAP_FRAME TrapFrame)
+{
+    /* Check if this is user-mode or V86 */
+    if ((TrapFrame->SegCs & MODE_MASK) || (TrapFrame->EFlags & X86_EFLAGS_VM))
+    {
+        /* Return it directly */
+        return TrapFrame->HardwareEsp;
+    }
+    else
+    {
+        /* Edited frame */
+        if (!(TrapFrame->SegCs & FRAME_EDITED))
+        {
+            /* Return edited value */
+            return TrapFrame->TempEsp;
+        }
+        else
+        {
+            /* Virgin frame, calculate */
+            return (ULONG)&TrapFrame->HardwareEsp;
+        }
+    }
+}
+
+VOID
+NTAPI
+KiEspToTrapFrame(IN PKTRAP_FRAME TrapFrame,
+                 IN ULONG Esp)
+{
+    ULONG Previous = KiEspFromTrapFrame(TrapFrame);
+
+    /* Check if this is user-mode or V86 */
+    if ((TrapFrame->SegCs & MODE_MASK) || (TrapFrame->EFlags & X86_EFLAGS_VM))
+    {
+        /* Write it directly */
+        TrapFrame->HardwareEsp = Esp;
+    }
+    else
+    {
+        /* Don't allow ESP to be lowered, this is illegal */
+        if (Esp < Previous)
+        {
+            KeBugCheck(SET_OF_INVALID_CONTEXT);
+        }
+
+        /* Create an edit frame, check if it was alrady */
+        if (!(TrapFrame->SegCs & FRAME_EDITED))
+        {
+            /* Update the value */
+            TrapFrame->TempEsp = Esp;
+        }
+        else
+        {
+            /* Check if ESP changed */
+            if (Previous != Esp)
+            {
+                /* Save CS */
+                TrapFrame->TempSegCs = TrapFrame->SegCs;
+                TrapFrame->SegCs &= ~FRAME_EDITED;
+
+                /* Save ESP */
+                TrapFrame->TempEsp = Esp;
+            }
+        }
+    }
+}
+
+ULONG
+NTAPI
+KiSsFromTrapFrame(IN PKTRAP_FRAME TrapFrame)
+{
+    /* If this was V86 Mode */
+    if (TrapFrame->EFlags & X86_EFLAGS_VM)
+    {
+        /* Just return it */
+        return TrapFrame->HardwareSegSs;
+    }
+    else if (TrapFrame->SegCs & MODE_MASK)
+    {
+        /* Usermode, return the User SS */
+        return TrapFrame->HardwareSegSs | RPL_MASK;
+    }
+    else
+    {
+        /* Kernel mode */
+        return KGDT_R0_DATA;
+    }
+}
+
+VOID
+NTAPI
+KiSsToTrapFrame(IN PKTRAP_FRAME TrapFrame,
+                IN ULONG Ss)
+{
+    /* Remove the high-bits */
+    Ss &= 0xFFFF;
+
+    /* If this was V86 Mode */
+    if (TrapFrame->EFlags & X86_EFLAGS_VM)
+    {
+        /* Just write it */
+        TrapFrame->HardwareSegSs = Ss;
+    }
+    else if (TrapFrame->SegCs & MODE_MASK)
+    {
+        /* Usermode, save the User SS */
+        TrapFrame->HardwareSegSs = Ss | RPL_MASK;
+    }
+}
+
 VOID
+NTAPI
+KeContextToTrapFrame(IN PCONTEXT Context,
+                     IN OUT PKEXCEPTION_FRAME ExceptionFrame,
+                     IN OUT PKTRAP_FRAME TrapFrame,
+                     IN ULONG ContextFlags,
+                     IN KPROCESSOR_MODE PreviousMode)
+{
+    PFX_SAVE_AREA FxSaveArea;
+    //ULONG i; Future Use
+    BOOLEAN V86Switch = FALSE;
+
+    /* Start with the basic Registers */
+    if ((ContextFlags & CONTEXT_CONTROL) == CONTEXT_CONTROL)
+    {
+        /* Check if we went through a V86 switch */
+        if ((Context->EFlags & X86_EFLAGS_VM) !=
+            (TrapFrame->EFlags & X86_EFLAGS_VM))
+        {
+            /* We did, remember this for later */
+            V86Switch = TRUE;
+        }
+
+        /* Copy EFLAGS. FIXME: Needs to be sanitized */
+        TrapFrame->EFlags = Context->EFlags;
+
+        /* Copy EBP and EIP */
+        TrapFrame->Ebp = Context->Ebp;
+        TrapFrame->Eip = Context->Eip;
+
+        /* Check if we were in V86 Mode */
+        if (TrapFrame->EFlags & X86_EFLAGS_VM)
+        {
+            /* Simply copy the CS value */
+            TrapFrame->SegCs = Context->SegCs;
+        }
+        else
+        {
+            /* We weren't in V86, so sanitize the CS (FIXME!) */
+            TrapFrame->SegCs = Context->SegCs;
+
+            /* Don't let it under 8, that's invalid */
+            if ((PreviousMode != KernelMode) && (TrapFrame->SegCs < 8))
+            {
+                /* Force it to User CS */
+                TrapFrame->SegCs = (KGDT_R3_CODE | RPL_MASK);
+            }
+        }
+
+        /* Handle SS Specially for validation */
+        KiSsToTrapFrame(TrapFrame, Context->SegSs);
+
+        /* Write ESP back; take into account Edited Trap Frames */
+        KiEspToTrapFrame(TrapFrame, Context->Esp);
+
+        /* Handle our V86 Bias if we went through a switch */
+        if (V86Switch) Ki386AdjustEsp0(TrapFrame);
+    }
+
+    /* Process the Integer Registers */
+    if ((ContextFlags & CONTEXT_INTEGER) == CONTEXT_INTEGER)
+    {
+        TrapFrame->Eax = Context->Eax;
+        TrapFrame->Ebx = Context->Ebx;
+        TrapFrame->Ecx = Context->Ecx;
+        TrapFrame->Edx = Context->Edx;
+        TrapFrame->Esi = Context->Esi;
+        TrapFrame->Edi = Context->Edi;
+    }
+
+    /* Process the Context Segments */
+    if ((ContextFlags & CONTEXT_SEGMENTS) == CONTEXT_SEGMENTS)
+    {
+        /* Check if we were in V86 Mode */
+        if (TrapFrame->EFlags & X86_EFLAGS_VM)
+        {
+            /* Copy the V86 Segments directlry */
+            TrapFrame->V86Ds = Context->SegDs;
+            TrapFrame->V86Es = Context->SegEs;
+            TrapFrame->V86Fs = Context->SegFs;
+            TrapFrame->V86Gs = Context->SegGs;
+        }
+        else if (!(TrapFrame->SegCs & MODE_MASK))
+        {
+            /* For kernel mode, write the standard values */
+            TrapFrame->SegDs = KGDT_R3_DATA | RPL_MASK;
+            TrapFrame->SegEs = KGDT_R3_DATA | RPL_MASK;
+            TrapFrame->SegFs = Context->SegFs;
+            TrapFrame->SegGs = 0;
+        }
+        else
+        {
+            /* For user mode, return the values directlry */
+            TrapFrame->SegDs = Context->SegDs;
+            TrapFrame->SegEs = Context->SegEs;
+            TrapFrame->SegFs = Context->SegFs;
+
+            /* Handle GS specially */
+            if (TrapFrame->SegCs == (KGDT_R3_CODE | RPL_MASK))
+            {
+                /* Don't use it, if user */
+                TrapFrame->SegGs = 0;
+            }
+            else
+            {
+                /* Copy it if kernel */
+                TrapFrame->SegGs = Context->SegGs;
+            }
+        }
+    }
+
+    /* Handle the extended registers */
+    if (((ContextFlags & CONTEXT_EXTENDED_REGISTERS) ==
+        CONTEXT_EXTENDED_REGISTERS) &&
+        ((TrapFrame->SegCs & MODE_MASK) == UserMode))
+    {
+        /* Get the FX Area */
+        FxSaveArea = (PFX_SAVE_AREA)(TrapFrame + 1);
+
+        /* Check if NPX is present */
+        if (KeI386NpxPresent)
+        {
+            /* Future use */
+        }
+    }
+
+    /* Handle the floating point state */
+    if (((ContextFlags & CONTEXT_FLOATING_POINT) ==
+        CONTEXT_FLOATING_POINT) &&
+        ((TrapFrame->SegCs & MODE_MASK) == UserMode))
+    {
+        /* Get the FX Area */
+        FxSaveArea = (PFX_SAVE_AREA)(TrapFrame + 1);
+
+        /* Check if NPX is present */
+        if (KeI386NpxPresent)
+        {
+            /* Future use */
+        }
+        else
+        {
+            /* Future use */
+        }
+    }
+
+    /* Handle the Debug Registers */
+    if ((ContextFlags & CONTEXT_DEBUG_REGISTERS) == CONTEXT_DEBUG_REGISTERS)
+    {
+        /* FIXME: All these should be sanitized */
+        TrapFrame->Dr0 = Context->Dr0;
+        TrapFrame->Dr1 = Context->Dr1;
+        TrapFrame->Dr2 = Context->Dr2;
+        TrapFrame->Dr3 = Context->Dr3;
+        TrapFrame->Dr6 = Context->Dr6;
+        TrapFrame->Dr7 = Context->Dr7;
+
+        /* Check if usermode */
+        if (PreviousMode != KernelMode)
+        {
+            /* Set the Debug Flag */
+            KeGetCurrentThread()->DispatcherHeader.DebugActive =
+                (Context->Dr7 & DR7_ACTIVE);
+        }
+    }
+
+    /* Handle FPU and Extended Registers */
+    KiContextToFxSaveArea((PFX_SAVE_AREA)(TrapFrame + 1), Context);
+}
+
+VOID
+NTAPI
+KeTrapFrameToContext(IN PKTRAP_FRAME TrapFrame,
+                     IN PKEXCEPTION_FRAME ExceptionFrame,
+                     IN OUT PCONTEXT Context)
+{
+    PFX_SAVE_AREA FxSaveArea = NULL;
+
+    /* Start with the Control flags */
+    if ((Context->ContextFlags & CONTEXT_CONTROL) == CONTEXT_CONTROL)
+    {
+        /* EBP, EIP and EFLAGS */
+        Context->Ebp = TrapFrame->Ebp;
+        Context->Eip = TrapFrame->Eip;
+        Context->EFlags = TrapFrame->EFlags;
+
+        /* Return the correct CS */
+        if (!(TrapFrame->SegCs & FRAME_EDITED) &&
+            !(TrapFrame->EFlags & X86_EFLAGS_VM))
+        {
+            /* Get it from the Temp location */
+            Context->SegCs = TrapFrame->TempSegCs & 0xFFFF;
+        }
+        else
+        {
+            /* Return it directly */
+            Context->SegCs = TrapFrame->SegCs & 0xFFFF;
+        }
+
+        /* Get the Ss and ESP */
+        Context->SegSs = KiSsFromTrapFrame(TrapFrame);
+        Context->Esp = KiEspFromTrapFrame(TrapFrame);
+    }
+
+    /* Handle the Segments */
+    if ((Context->ContextFlags & CONTEXT_SEGMENTS) == CONTEXT_SEGMENTS)
+    {
+        /* Do V86 Mode first */
+        if (TrapFrame->EFlags & X86_EFLAGS_VM)
+        {
+            /* Return from the V86 location */
+            Context->SegGs = TrapFrame->V86Gs & 0xFFFF;
+            Context->SegFs = TrapFrame->V86Fs & 0xFFFF;
+            Context->SegEs = TrapFrame->V86Es & 0xFFFF;
+            Context->SegDs = TrapFrame->V86Ds & 0xFFFF;
+        }
+        else
+        {
+            /* Check if this was a Kernel Trap */
+            if (TrapFrame->SegCs == KGDT_R0_CODE)
+            {
+                /* Set valid selectors */
+                TrapFrame->SegGs = 0;
+                TrapFrame->SegFs = KGDT_R0_PCR;
+                TrapFrame->SegEs = KGDT_R3_DATA | RPL_MASK;
+                TrapFrame->SegDs = KGDT_R3_DATA | RPL_MASK;
+            }
+
+            /* Return the segments */
+            Context->SegGs = TrapFrame->SegGs & 0xFFFF;
+            Context->SegFs = TrapFrame->SegFs & 0xFFFF;
+            Context->SegEs = TrapFrame->SegEs & 0xFFFF;
+            Context->SegDs = TrapFrame->SegDs & 0xFFFF;
+        }
+    }
+
+    /* Handle the simple registers */
+    if ((Context->ContextFlags & CONTEXT_INTEGER) == CONTEXT_INTEGER)
+    {
+        /* Return them directly */
+        Context->Eax = TrapFrame->Eax;
+        Context->Ebx = TrapFrame->Ebx;
+        Context->Ecx = TrapFrame->Ecx;
+        Context->Edx = TrapFrame->Edx;
+        Context->Esi = TrapFrame->Esi;
+        Context->Edi = TrapFrame->Edi;
+    }
+
+    /* Handle extended registers */
+    if (((Context->ContextFlags & CONTEXT_EXTENDED_REGISTERS) ==
+        CONTEXT_EXTENDED_REGISTERS) &&
+        ((TrapFrame->SegCs & MODE_MASK) == UserMode))
+    {
+        /* Get the FX Save Area */
+        FxSaveArea = (PFX_SAVE_AREA)(TrapFrame + 1);
+
+        /* Make sure NPX is present */
+        if (KeI386NpxPresent)
+        {
+            /* Future use */
+        }
+
+        /* Old code */
+        FxSaveArea = KiGetFpuState(KeGetCurrentThread());
+        if (FxSaveArea != NULL)
+        {
+            memcpy(Context->ExtendedRegisters, &FxSaveArea->U.FxArea,
+                   min(sizeof (Context->ExtendedRegisters), sizeof (FxSaveArea->U.FxArea)) );
+        }
+        else
+        {
+            Context->ContextFlags &= (~CONTEXT_EXTENDED_REGISTERS) | CONTEXT_i386;
+        }
+    }
+
+    /* Handle Floating Point */
+    if (((Context->ContextFlags & CONTEXT_FLOATING_POINT) ==
+        CONTEXT_FLOATING_POINT) &&
+        ((TrapFrame->SegCs & MODE_MASK) == UserMode))
+    {
+        /* Get the FX Save Area */
+        FxSaveArea = (PFX_SAVE_AREA)(TrapFrame + 1);
+
+        /* Make sure we have an NPX */
+        if (KeI386NpxPresent)
+        {
+            /* Future use */
+        }
+        else
+        {
+            /* Future Use */
+        }
+
+        /* Old code */
+        FxSaveArea = KiGetFpuState(KeGetCurrentThread());
+        if (FxSaveArea != NULL)
+        {
+            KiFxSaveAreaToFloatingSaveArea(&Context->FloatSave, FxSaveArea);
+        }
+        else
+        {
+            Context->ContextFlags &= (~CONTEXT_FLOATING_POINT) | CONTEXT_i386;
+        }
+    }
+
+    /* Handle debug registers */
+    if ((Context->ContextFlags & CONTEXT_DEBUG_REGISTERS) ==
+        CONTEXT_DEBUG_REGISTERS)
+    {
+        /* Copy the debug registers */
+        Context->Dr0 = TrapFrame->Dr0;
+        Context->Dr1 = TrapFrame->Dr1;
+        Context->Dr2 = TrapFrame->Dr2;
+        Context->Dr3 = TrapFrame->Dr3;
+        Context->Dr6 = TrapFrame->Dr6;
+
+        /* For user-mode, only set DR7 if a debugger is active */
+        if (((TrapFrame->SegCs & MODE_MASK) ||
+            (TrapFrame->EFlags & EFLAGS_V86_MASK)) &&
+            (KeGetCurrentThread()->DispatcherHeader.DebugActive))
+        {
+            /* Copy it over */
+            Context->Dr7 = TrapFrame->Dr7;
+        }
+        else
+        {
+            /* Clear it */
+            Context->Dr7 = 0;
+        }
+    }
+}
+
+VOID
+NTAPI
 KeDumpStackFrames(PULONG Frame)
 {
-       DbgPrint("Frames: ");
+       PULONG StackBase, StackEnd;
+       MEMORY_BASIC_INFORMATION mbi;
+       ULONG ResultLength = sizeof(mbi);
+       NTSTATUS Status;
+
+       DbgPrint("Frames:\n");
        _SEH_TRY
        {
-               while ( MmIsAddressValid(Frame) )
+               Status = MiQueryVirtualMemory (
+                       (HANDLE)-1,
+                       Frame,
+                       MemoryBasicInformation,
+                       &mbi,
+                       sizeof(mbi),
+                       &ResultLength );
+               if ( !NT_SUCCESS(Status) )
+               {
+                       DPRINT1("Can't dump stack frames: MiQueryVirtualMemory() failed: %x\n", Status );
+                       return;
+               }
+
+               StackBase = Frame;
+               StackEnd = (PULONG)((ULONG_PTR)mbi.BaseAddress + mbi.RegionSize);
+
+               while ( Frame >= StackBase && Frame < StackEnd )
                {
                        ULONG Addr = Frame[1];
                        if (!KeRosPrintAddress((PVOID)Addr))
                                DbgPrint("<%X>", Addr);
                        if ( Addr == 0 || Addr == 0xDEADBEEF )
                                break;
+                       StackBase = Frame;
                        Frame = (PULONG)Frame[0];
-                       DbgPrint(" ");
+                       DbgPrint("\n");
                }
        }
        _SEH_HANDLE
@@ -655,6 +1044,10 @@ VOID STDCALL
 KeRosDumpStackFrames ( PULONG Frame, ULONG FrameCount )
 {
        ULONG i=0;
+       PULONG StackBase, StackEnd;
+       MEMORY_BASIC_INFORMATION mbi;
+       ULONG ResultLength = sizeof(mbi);
+       NTSTATUS Status;
 
        DbgPrint("Frames: ");
        _SEH_TRY
@@ -662,19 +1055,37 @@ KeRosDumpStackFrames ( PULONG Frame, ULONG FrameCount )
                if ( !Frame )
                {
 #if defined __GNUC__
-                       __asm__("mov %%ebp, %%ebx" : "=b" (Frame) : );
+                       __asm__("mov %%ebp, %0" : "=r" (Frame) : );
 #elif defined(_MSC_VER)
                        __asm mov [Frame], ebp
 #endif
                        //Frame = (PULONG)Frame[0]; // step out of KeRosDumpStackFrames
                }
-               while ( MmIsAddressValid(Frame) && i++ < FrameCount )
+
+               Status = MiQueryVirtualMemory (
+                       (HANDLE)-1,
+                       Frame,
+                       MemoryBasicInformation,
+                       &mbi,
+                       sizeof(mbi),
+                       &ResultLength );
+               if ( !NT_SUCCESS(Status) )
+               {
+                       DPRINT1("Can't dump stack frames: MiQueryVirtualMemory() failed: %x\n", Status );
+                       return;
+               }
+
+               StackBase = Frame;
+               StackEnd = (PULONG)((ULONG_PTR)mbi.BaseAddress + mbi.RegionSize);
+
+               while ( Frame >= StackBase && Frame < StackEnd && i++ < FrameCount )
                {
                        ULONG Addr = Frame[1];
                        if (!KeRosPrintAddress((PVOID)Addr))
                                DbgPrint("<%X>", Addr);
                        if ( Addr == 0 || Addr == 0xDEADBEEF )
                                break;
+                       StackBase = Frame;
                        Frame = (PULONG)Frame[0];
                        DbgPrint(" ");
                }
@@ -690,17 +1101,39 @@ ULONG STDCALL
 KeRosGetStackFrames ( PULONG Frames, ULONG FrameCount )
 {
        ULONG Count = 0;
-       PULONG Frame;
+       PULONG StackBase, StackEnd, Frame;
+       MEMORY_BASIC_INFORMATION mbi;
+       ULONG ResultLength = sizeof(mbi);
+       NTSTATUS Status;
+
        _SEH_TRY
        {
 #if defined __GNUC__
-               __asm__("mov %%ebp, %%ebx" : "=b" (Frame) : );
+               __asm__("mov %%ebp, %0" : "=r" (Frame) : );
 #elif defined(_MSC_VER)
                __asm mov [Frame], ebp
 #endif
-               while ( Count < FrameCount )
+
+               Status = MiQueryVirtualMemory (
+                       (HANDLE)-1,
+                       Frame,
+                       MemoryBasicInformation,
+                       &mbi,
+                       sizeof(mbi),
+                       &ResultLength );
+               if ( !NT_SUCCESS(Status) )
+               {
+                       DPRINT1("Can't get stack frames: MiQueryVirtualMemory() failed: %x\n", Status );
+                       return 0;
+               }
+
+               StackBase = Frame;
+               StackEnd = (PULONG)((ULONG_PTR)mbi.BaseAddress + mbi.RegionSize);
+
+               while ( Count < FrameCount && Frame >= StackBase && Frame < StackEnd )
                {
                        Frames[Count++] = Frame[1];
+                       StackBase = Frame;
                        Frame = (PULONG)Frame[0];
                }
        }
@@ -711,125 +1144,218 @@ KeRosGetStackFrames ( PULONG Frames, ULONG FrameCount )
        return Count;
 }
 
-static void
-set_system_call_gate(unsigned int sel, unsigned int func)
+VOID
+INIT_FUNCTION
+NTAPI
+KeInitExceptions(VOID)
 {
-   DPRINT("sel %x %d\n",sel,sel);
-   KiIdt[sel].a = (((int)func)&0xffff) +
-     (KERNEL_CS << 16);
-   KiIdt[sel].b = 0xef00 + (((int)func)&0xffff0000);
-   DPRINT("idt[sel].b %x\n",KiIdt[sel].b);
-}
+    ULONG i;
+    USHORT FlippedSelector;
 
-static void set_interrupt_gate(unsigned int sel, unsigned int func)
-{
-   DPRINT("set_interrupt_gate(sel %d, func %x)\n",sel,func);
-   KiIdt[sel].a = (((int)func)&0xffff) +
-     (KERNEL_CS << 16);
-   KiIdt[sel].b = 0x8e00 + (((int)func)&0xffff0000);
-}
+    /* Loop the IDT */
+    for (i = 0; i <= MAXIMUM_IDTVECTOR; i ++)
+    {
+        /* Save the current Selector */
+        FlippedSelector = KiIdt[i].Selector;
 
-static void set_trap_gate(unsigned int sel, unsigned int func, unsigned int dpl)
-{
-   DPRINT("set_trap_gate(sel %d, func %x, dpl %d)\n",sel, func, dpl);
-   ASSERT(dpl <= 3);
-   KiIdt[sel].a = (((int)func)&0xffff) +
-     (KERNEL_CS << 16);
-   KiIdt[sel].b = 0x8f00 + (dpl << 13) + (((int)func)&0xffff0000);
+        /* Flip Selector and Extended Offset */
+        KiIdt[i].Selector = KiIdt[i].ExtendedOffset;
+        KiIdt[i].ExtendedOffset = FlippedSelector;
+    }
 }
 
-static void
-set_task_gate(unsigned int sel, unsigned task_sel)
+VOID
+NTAPI
+KiDispatchException(PEXCEPTION_RECORD ExceptionRecord,
+                    PKEXCEPTION_FRAME ExceptionFrame,
+                    PKTRAP_FRAME TrapFrame,
+                    KPROCESSOR_MODE PreviousMode,
+                    BOOLEAN FirstChance)
 {
-  KiIdt[sel].a = task_sel << 16;
-  KiIdt[sel].b = 0x8500;
-}
+    CONTEXT Context;
+    KD_CONTINUE_TYPE Action;
+    ULONG_PTR Stack, NewStack;
+    ULONG Size;
+    BOOLEAN UserDispatch = FALSE;
+    DPRINT("KiDispatchException() called\n");
 
-VOID INIT_FUNCTION
-KeInitExceptions(VOID)
-/*
- * FUNCTION: Initalize CPU exception handling
- */
-{
-   int i;
+    /* Increase number of Exception Dispatches */
+    KeGetCurrentPrcb()->KeExceptionDispatchCount++;
 
-   DPRINT("KeInitExceptions()\n");
+    /* Set the context flags */
+    Context.ContextFlags = CONTEXT_FULL | CONTEXT_DEBUG_REGISTERS;
 
-   /*
-    * Set up the other gates
-    */
-   set_trap_gate(0, (ULONG)KiTrap0, 0);
-   set_trap_gate(1, (ULONG)KiTrap1, 0);
-   set_trap_gate(2, (ULONG)KiTrap2, 0);
-   set_trap_gate(3, (ULONG)KiTrap3, 3);
-   set_trap_gate(4, (ULONG)KiTrap4, 0);
-   set_trap_gate(5, (ULONG)KiTrap5, 0);
-   set_trap_gate(6, (ULONG)KiTrap6, 0);
-   set_trap_gate(7, (ULONG)KiTrap7, 0);
-   set_task_gate(8, TRAP_TSS_SELECTOR);
-   set_trap_gate(9, (ULONG)KiTrap9, 0);
-   set_trap_gate(10, (ULONG)KiTrap10, 0);
-   set_trap_gate(11, (ULONG)KiTrap11, 0);
-   set_trap_gate(12, (ULONG)KiTrap12, 0);
-   set_trap_gate(13, (ULONG)KiTrap13, 0);
-   set_interrupt_gate(14, (ULONG)KiTrap14);
-   set_trap_gate(15, (ULONG)KiTrap15, 0);
-   set_trap_gate(16, (ULONG)KiTrap16, 0);
-   set_trap_gate(17, (ULONG)KiTrap17, 0);
-   set_trap_gate(18, (ULONG)KiTrap18, 0);
-   set_trap_gate(19, (ULONG)KiTrap19, 0);
-
-   for (i = 20; i < 256; i++)
-     {
-        set_trap_gate(i,(int)KiTrapUnknown, 0);
-     }
+    /* Check if User Mode */
+    if (PreviousMode == UserMode)
+    {
+        /* Add the FPU Flag */
+        Context.ContextFlags |= CONTEXT_FLOATING_POINT;
+        if (KeI386FxsrPresent) Context.ContextFlags |= CONTEXT_EXTENDED_REGISTERS;
+    }
+
+    /* Get a Context */
+    KeTrapFrameToContext(TrapFrame, ExceptionFrame, &Context);
+
+    /* Handle kernel-mode first, it's simpler */
+    if (PreviousMode == KernelMode)
+    {
+        /* Check if this is a first-chance exception */
+        if (FirstChance == TRUE)
+        {
+            /* Break into the debugger for the first time */
+            Action = KdpEnterDebuggerException(ExceptionRecord,
+                                               PreviousMode,
+                                               &Context,
+                                               TrapFrame,
+                                               TRUE,
+                                               TRUE);
+
+            /* If the debugger said continue, then continue */
+            if (Action == kdContinue) goto Handled;
+
+            /* If the Debugger couldn't handle it, dispatch the exception */
+            if (RtlDispatchException(ExceptionRecord, &Context))
+            {
+                /* It was handled by an exception handler, continue */
+                goto Handled;
+            }
+        }
+
+        /* This is a second-chance exception, only for the debugger */
+        Action = KdpEnterDebuggerException(ExceptionRecord,
+                                           PreviousMode,
+                                           &Context,
+                                           TrapFrame,
+                                           FALSE,
+                                           FALSE);
+
+        /* If the debugger said continue, then continue */
+        if (Action == kdContinue) goto Handled;
+
+        /* Third strike; you're out */
+        KEBUGCHECKWITHTF(KMODE_EXCEPTION_NOT_HANDLED,
+                         ExceptionRecord->ExceptionCode,
+                         (ULONG_PTR)ExceptionRecord->ExceptionAddress,
+                         ExceptionRecord->ExceptionInformation[0],
+                         ExceptionRecord->ExceptionInformation[1],
+                         TrapFrame);
+    }
+    else
+    {
+        /* User mode exception, was it first-chance? */
+        if (FirstChance)
+        {
+            /* Enter Debugger if available */
+            Action = KdpEnterDebuggerException(ExceptionRecord,
+                                               PreviousMode,
+                                               &Context,
+                                               TrapFrame,
+                                               TRUE,
+                                               TRUE);
+
+            /* Exit if we're continuing */
+            if (Action == kdContinue) goto Handled;
+
+            /* FIXME: Forward exception to user mode debugger */
+
+            /* Set up the user-stack */
+            _SEH_TRY
+            {
+                /* Align context size and get stack pointer */
+                Size = (sizeof(CONTEXT) + 3) & ~3;
+                Stack = (Context.Esp & ~3) - Size;
+                DPRINT("Stack: %lx\n", Stack);
+
+                /* Probe stack and copy Context */
+                ProbeForWrite((PVOID)Stack, Size, sizeof(ULONG));
+                RtlCopyMemory((PVOID)Stack, &Context, sizeof(CONTEXT));
+
+                /* Align exception record size and get stack pointer */
+                Size = (sizeof(EXCEPTION_RECORD) - 
+                        (EXCEPTION_MAXIMUM_PARAMETERS - ExceptionRecord->NumberParameters) *
+                        sizeof(ULONG) + 3) & ~3;
+                NewStack = Stack - Size;
+                DPRINT("NewStack: %lx\n", NewStack);
+
+                /* Probe stack and copy exception record. Don't forget to add the two params */
+                ProbeForWrite((PVOID)(NewStack - 2 * sizeof(ULONG_PTR)),
+                              Size +  2 * sizeof(ULONG_PTR),
+                              sizeof(ULONG));
+                RtlCopyMemory((PVOID)NewStack, ExceptionRecord, Size);
+
+                /* Now write the two params for the user-mode dispatcher */
+                *(PULONG_PTR)(NewStack - 1 * sizeof(ULONG_PTR)) = Stack;
+                *(PULONG_PTR)(NewStack - 2 * sizeof(ULONG_PTR)) = NewStack;
+
+                /* Set new Stack Pointer */
+                KiEspToTrapFrame(TrapFrame, NewStack - 2 * sizeof(ULONG_PTR));
+
+                /* Set EIP to the User-mode Dispathcer */
+                TrapFrame->Eip = (ULONG)KeUserExceptionDispatcher;
+                UserDispatch = TRUE;
+                _SEH_LEAVE;
+            }
+            _SEH_HANDLE
+            {
+                /* Do second-chance */
+            }
+            _SEH_END;
+        }
+
+        /* If we dispatch to user, return now */
+        if (UserDispatch) return;
+
+        /* FIXME: Forward the exception to the debugger for 2nd chance */
+
+        /* 3rd strike, kill the thread */
+        DPRINT1("Unhandled UserMode exception, terminating thread\n");
+        ZwTerminateThread(NtCurrentThread(), ExceptionRecord->ExceptionCode);
+        KEBUGCHECKWITHTF(KMODE_EXCEPTION_NOT_HANDLED,
+                         ExceptionRecord->ExceptionCode,
+                         (ULONG_PTR)ExceptionRecord->ExceptionAddress,
+                         ExceptionRecord->ExceptionInformation[0],
+                         ExceptionRecord->ExceptionInformation[1],
+                         TrapFrame);
+    }
 
-   set_system_call_gate(0x2d,(int)interrupt_handler2d);
-   set_system_call_gate(0x2e,(int)interrupt_handler2e);
+Handled:
+    /* Convert the context back into Trap/Exception Frames */
+    KeContextToTrapFrame(&Context,
+                         NULL,
+                         TrapFrame,
+                         Context.ContextFlags,
+                         PreviousMode);
+    return;
 }
 
 /*
  * @implemented
  */
-
-NTSTATUS STDCALL
+NTSTATUS
+NTAPI
 KeRaiseUserException(IN NTSTATUS ExceptionCode)
 {
-   /* FIXME: This needs SEH */
    ULONG OldEip;
    PKTHREAD Thread = KeGetCurrentThread();
 
-   ProbeForWrite(&Thread->Teb->ExceptionCode, sizeof(NTSTATUS), sizeof(NTSTATUS)); /* NT doesn't check this -- bad? */
-   OldEip = Thread->TrapFrame->Eip;
-   Thread->TrapFrame->Eip = (ULONG_PTR)LdrpGetSystemDllRaiseExceptionDispatcher();
-   Thread->Teb->ExceptionCode = ExceptionCode;
-   return((NTSTATUS)OldEip);
-}
-
-VOID
-FASTCALL
-KeRosTrapReturn ( PKTRAP_FRAME TrapFrame, PKTRAP_FRAME PrevTrapFrame );
-
-/*
- * @implemented
- */
-NTSTATUS STDCALL
-NtRaiseException (
-       IN PEXCEPTION_RECORD ExceptionRecord,
-       IN PCONTEXT Context,
-       IN BOOLEAN SearchFrames)
-{
-       PKTRAP_FRAME TrapFrame = KeGetCurrentThread()->TrapFrame;
-       PKTRAP_FRAME PrevTrapFrame = (PKTRAP_FRAME)TrapFrame->Edx;
+   /* Make sure we can access the TEB */
+    _SEH_TRY
+    {
+        Thread->Teb->ExceptionCode = ExceptionCode;
+    }
+    _SEH_HANDLE
+    {
+        return(ExceptionCode);
+    }
+    _SEH_END;
 
-       KeGetCurrentKPCR()->Tib.ExceptionList = TrapFrame->ExceptionList;
+    /* Get the old EIP */
+    OldEip = Thread->TrapFrame->Eip;
 
-       KiDispatchException(ExceptionRecord,
-               Context,
-               PsGetCurrentThread()->Tcb.TrapFrame,
-               (KPROCESSOR_MODE)ExGetPreviousMode(),
-               SearchFrames);
+    /* Change it to the user-mode dispatcher */
+    Thread->TrapFrame->Eip = (ULONG_PTR)KeRaiseUserExceptionDispatcher;
 
-       KeRosTrapReturn ( TrapFrame, PrevTrapFrame );
-       return(STATUS_SUCCESS);
+    /* Return the old EIP */
+    return((NTSTATUS)OldEip);
 }
+