diff --git a/reactos/include/ndk/mmtypes.h b/reactos/include/ndk/mmtypes.h
index 11889dbfc75..6fd9cf271d5 100644
--- a/reactos/include/ndk/mmtypes.h
+++ b/reactos/include/ndk/mmtypes.h
@@ -28,9 +28,9 @@ Author:
 //
 // Page-Rounding Macros
 //
-#define PAGE_ROUND_DOWN(x) (((ULONG)x)&(~(PAGE_SIZE-1)))
+#define PAGE_ROUND_DOWN(x) (((ULONG_PTR)x)&(~(PAGE_SIZE-1)))
 #define PAGE_ROUND_UP(x)    \
-    ( (((ULONG)x)%PAGE_SIZE) ? ((((ULONG)x)&(~(PAGE_SIZE-1)))+PAGE_SIZE) : ((ULONG)x) )
+    ( (((ULONG_PTR)x)%PAGE_SIZE) ? ((((ULONG_PTR)x)&(~(PAGE_SIZE-1)))+PAGE_SIZE) : ((ULONG_PTR)x) )
 
 //
 // Macro for generating pool tags
diff --git a/reactos/include/reactos/helper.h b/reactos/include/reactos/helper.h
index c7d933ec869..7d003b0c6bf 100644
--- a/reactos/include/reactos/helper.h
+++ b/reactos/include/reactos/helper.h
@@ -20,11 +20,11 @@
 #endif
 
 #ifndef PAGE_ROUND_DOWN
-#define PAGE_ROUND_DOWN(x) (((ULONG)x)&(~(PAGE_SIZE-1)))
+#define PAGE_ROUND_DOWN(x) (((ULONG_PTR)x)&(~(PAGE_SIZE-1)))
 #endif
 
 #ifndef PAGE_ROUND_UP
-#define PAGE_ROUND_UP(x) ( (((ULONG)x)%PAGE_SIZE) ? ((((ULONG)x)&(~(PAGE_SIZE-1)))+PAGE_SIZE) : ((ULONG)x) )
+#define PAGE_ROUND_UP(x) ( (((ULONG_PTR)x)%PAGE_SIZE) ? ((((ULONG_PTR)x)&(~(PAGE_SIZE-1)))+PAGE_SIZE) : ((ULONG_PTR)x) )
 #endif
 
 #define ABS_VALUE(V) (((V) < 0) ? -(V) : (V))
diff --git a/reactos/ntoskrnl/ex/init.c b/reactos/ntoskrnl/ex/init.c
index ff5f5f193bc..a4a06d79536 100644
--- a/reactos/ntoskrnl/ex/init.c
+++ b/reactos/ntoskrnl/ex/init.c
@@ -89,7 +89,7 @@ InitSystemSharedUserPage (PCSZ ParameterLine)
 
     /* Create local parameter line copy */
     ParamBuffer = ExAllocatePool(PagedPool, 256);
-    strcpy (ParamBuffer, (char *)ParameterLine);
+    strcpy (ParamBuffer, (const char *)ParameterLine);
     DPRINT("%s\n", ParamBuffer);
 
     /* Cut options off */
diff --git a/reactos/ntoskrnl/include/internal/ntoskrnl.h b/reactos/ntoskrnl/include/internal/ntoskrnl.h
index ada3859dea5..fb92bffe5b8 100644
--- a/reactos/ntoskrnl/include/internal/ntoskrnl.h
+++ b/reactos/ntoskrnl/include/internal/ntoskrnl.h
@@ -123,7 +123,7 @@ static const ULARGE_INTEGER __emptyULargeInteger = {{0, 0}};
     (((ULONG_PTR)(Ptr) + sizeof(Type) - 1 < (ULONG_PTR)(Ptr) ||                \
 	 (ULONG_PTR)(Ptr) + sizeof(Type) - 1 >= (ULONG_PTR)MmUserProbeAddress) ?   \
 	     ExRaiseStatus (STATUS_ACCESS_VIOLATION), Default :                    \
-	     *(Type *)&(*(volatile Type *)(Ptr)))
+	     *(Type *)(Ptr))
 
 #define ProbeForReadBoolean(Ptr) ProbeForReadGenericType(Ptr, BOOLEAN, FALSE)
 #define ProbeForReadUchar(Ptr) ProbeForReadGenericType(Ptr, UCHAR, 0)
diff --git a/reactos/ntoskrnl/io/deviface.c b/reactos/ntoskrnl/io/deviface.c
index 37c385671a1..6644548567a 100644
--- a/reactos/ntoskrnl/io/deviface.c
+++ b/reactos/ntoskrnl/io/deviface.c
@@ -882,6 +882,7 @@ IoSetDeviceInterfaceState(
    PWCHAR StartPosition;
    PWCHAR EndPosition;
    NTSTATUS Status;
+   GUID EventGuid;
 
    if (SymbolicLinkName == NULL)
       return STATUS_INVALID_PARAMETER_1;
@@ -917,10 +918,11 @@ IoSetDeviceInterfaceState(
       return Status;
    }
 
+   EventGuid = Enable ? GUID_DEVICE_INTERFACE_ARRIVAL : GUID_DEVICE_INTERFACE_REMOVAL;
    IopNotifyPlugPlayNotification(
       PhysicalDeviceObject,
       EventCategoryDeviceInterfaceChange,
-      Enable ? (LPGUID)&GUID_DEVICE_INTERFACE_ARRIVAL : (LPGUID)&GUID_DEVICE_INTERFACE_REMOVAL,
+      &EventGuid,
       &GuidString,
       (PVOID)SymbolicLinkName);
 
diff --git a/reactos/ntoskrnl/io/pnpmgr.c b/reactos/ntoskrnl/io/pnpmgr.c
index b2785ce6c50..3c34d402e0a 100644
--- a/reactos/ntoskrnl/io/pnpmgr.c
+++ b/reactos/ntoskrnl/io/pnpmgr.c
@@ -221,7 +221,7 @@ IoGetDeviceProperty(
 
         /* Query the device caps */
         Status = IopQueryDeviceCapabilities(DeviceNode, &DeviceCaps);
-        if (NT_SUCCESS(Status) && (DeviceCaps.Address != -1))
+        if (NT_SUCCESS(Status) && (DeviceCaps.Address != (ULONG)-1))
         {
             /* Return length */
             *ResultLength = sizeof(ULONG);
diff --git a/reactos/ntoskrnl/kd/kdmain.c b/reactos/ntoskrnl/kd/kdmain.c
index a0b68d03e38..88b5e0424f1 100644
--- a/reactos/ntoskrnl/kd/kdmain.c
+++ b/reactos/ntoskrnl/kd/kdmain.c
@@ -217,7 +217,7 @@ STDCALL
 NtQueryDebugFilterState(IN ULONG ComponentId,
                         IN ULONG Level)
 {
-	int i;
+	unsigned int i;
 
 	/* convert Level to mask if it isn't already one */
 	if ( Level < 32 )
@@ -241,7 +241,7 @@ NtSetDebugFilterState(IN ULONG ComponentId,
                       IN ULONG Level,
                       IN BOOLEAN State)
 {
-	int i;
+	unsigned int i;
 	for ( i = 0; i < KdComponentTableEntries; i++ )
 	{
 		if ( ComponentId == KdComponentTable[i].ComponentId )
diff --git a/reactos/ntoskrnl/lpc/reply.c b/reactos/ntoskrnl/lpc/reply.c
index e42e30b06ed..e67db081f06 100644
--- a/reactos/ntoskrnl/lpc/reply.c
+++ b/reactos/ntoskrnl/lpc/reply.c
@@ -45,7 +45,7 @@ EiReplyOrRequestPort (IN	PEPORT		Port,
      }
 
    Size = sizeof(QUEUEDMESSAGE);
-   if (LpcReply && LpcReply->u1.s1.TotalLength > sizeof(PORT_MESSAGE))
+   if (LpcReply && LpcReply->u1.s1.TotalLength > (CSHORT)sizeof(PORT_MESSAGE))
      {
        Size += LpcReply->u1.s1.TotalLength - sizeof(PORT_MESSAGE);
      }
diff --git a/reactos/ntoskrnl/mm/elf.inc.h b/reactos/ntoskrnl/mm/elf.inc.h
index 3d3e27e4bf5..655096a501e 100644
--- a/reactos/ntoskrnl/mm/elf.inc.h
+++ b/reactos/ntoskrnl/mm/elf.inc.h
@@ -139,7 +139,7 @@ static __inline BOOLEAN Intsafe_CanOffsetPointer
 
 #ifndef RTL_CONTAINS_FIELD
 #define RTL_CONTAINS_FIELD(P_, SIZE_, FIELD_) \
- ((((char *)(P_)) + (SIZE_)) > (((char *)(&((P_)->FIELD_))) + sizeof((P_)->FIELD_)))
+ ((ULONG_PTR)(P_) + (ULONG_PTR)(SIZE_) > (ULONG_PTR)&((P_)->FIELD_) + sizeof((P_)->FIELD_))
 #endif
 
 #define ELFFMT_FIELDS_EQUAL(TYPE1_, TYPE2_, FIELD_) \
@@ -266,8 +266,13 @@ static __inline ULONG ElfFmtpSafeReadULong
 {
  PBYTE p;
  ULONG nSafeInput;
+ union
+ {
+     CONST ULONG32 *ConstInput;
+     ULONG32 *Input;
+ }pInput = {Input};
 
- RtlRetrieveUlong(&nSafeInput, Input);
+ RtlRetrieveUlong(&nSafeInput, pInput.Input);
 
  if(DataType == ELF_TARG_DATA)
   return nSafeInput;
diff --git a/reactos/ntoskrnl/mm/pe.c b/reactos/ntoskrnl/mm/pe.c
index ce9fb8bf8f0..c0f7df023f9 100644
--- a/reactos/ntoskrnl/mm/pe.c
+++ b/reactos/ntoskrnl/mm/pe.c
@@ -97,7 +97,7 @@ static __inline BOOLEAN Intsafe_CanOffsetPointer(IN CONST VOID * Pointer, IN SIZ
 
 #ifndef RTL_CONTAINS_FIELD
 #define RTL_CONTAINS_FIELD(P_, SIZE_, FIELD_) \
- ((((char *)(P_)) + (SIZE_)) > (((char *)(&((P_)->FIELD_))) + sizeof((P_)->FIELD_)))
+  ((ULONG_PTR)(P_) + (ULONG_PTR)(SIZE_) > (ULONG_PTR)&((P_)->FIELD_) + sizeof((P_)->FIELD_))
 #endif
 
 static __inline BOOLEAN IsPowerOf2(IN ULONG Number)
diff --git a/reactos/ntoskrnl/mm/section.c b/reactos/ntoskrnl/mm/section.c
index ac8895e8515..f766f900ab6 100644
--- a/reactos/ntoskrnl/mm/section.c
+++ b/reactos/ntoskrnl/mm/section.c
@@ -2744,8 +2744,8 @@ __cdecl
 MmspCompareSegments(const void * x,
                     const void * y)
 {
-   PMM_SECTION_SEGMENT Segment1 = (PMM_SECTION_SEGMENT)x;
-   PMM_SECTION_SEGMENT Segment2 = (PMM_SECTION_SEGMENT)y;
+   const MM_SECTION_SEGMENT *Segment1 = (const MM_SECTION_SEGMENT *)x;
+   const MM_SECTION_SEGMENT *Segment2 = (const MM_SECTION_SEGMENT *)y;
 
    return
       (Segment1->VirtualAddress - Segment2->VirtualAddress) >>
diff --git a/reactos/ntoskrnl/mm/virtual.c b/reactos/ntoskrnl/mm/virtual.c
index a8c0b06b797..557557ddde2 100644
--- a/reactos/ntoskrnl/mm/virtual.c
+++ b/reactos/ntoskrnl/mm/virtual.c
@@ -989,20 +989,20 @@ ProbeForRead (IN CONST VOID *Address,
               IN ULONG Length,
               IN ULONG Alignment)
 {
-   ASSERT(Alignment == 1 || Alignment == 2 || Alignment == 4 || Alignment == 8);
+    if (Length != 0)
+    {
+        ASSERT(Alignment == 1 || Alignment == 2 || Alignment == 4 || Alignment == 8);
 
-   if (Length == 0)
-      return;
-
-   if (((ULONG_PTR)Address & (Alignment - 1)) != 0)
-   {
-      ExRaiseStatus (STATUS_DATATYPE_MISALIGNMENT);
-   }
-   else if ((ULONG_PTR)Address + Length - 1 < (ULONG_PTR)Address ||
-            (ULONG_PTR)Address + Length - 1 >= (ULONG_PTR)MmUserProbeAddress)
-   {
-      ExRaiseStatus (STATUS_ACCESS_VIOLATION);
-   }
+        if (((ULONG_PTR)Address & (Alignment - 1)) != 0)
+        {
+            ExRaiseStatus (STATUS_DATATYPE_MISALIGNMENT);
+        }
+        else if ((ULONG_PTR)Address + Length - 1 < (ULONG_PTR)Address ||
+                 (ULONG_PTR)Address + Length - 1 >= (ULONG_PTR)MmUserProbeAddress)
+        {
+            ExRaiseStatus (STATUS_ACCESS_VIOLATION);
+        }
+    }
 }
 
 
@@ -1010,39 +1010,39 @@ ProbeForRead (IN CONST VOID *Address,
  * @implemented
  */
 VOID STDCALL
-ProbeForWrite (IN CONST VOID *Address,
+ProbeForWrite (IN PVOID Address,
                IN ULONG Length,
                IN ULONG Alignment)
 {
-   volatile CHAR *Current;
-   PCHAR Last;
+    volatile CHAR *Current;
+    PCHAR Last;
 
-   ASSERT(Alignment == 1 || Alignment == 2 || Alignment == 4 || Alignment == 8);
+    if (Length != 0)
+    {
+        ASSERT(Alignment == 1 || Alignment == 2 || Alignment == 4 || Alignment == 8);
 
-   if (Length == 0)
-      return;
+        if (((ULONG_PTR)Address & (Alignment - 1)) != 0)
+        {
+            ExRaiseStatus (STATUS_DATATYPE_MISALIGNMENT);
+        }
 
-   if (((ULONG_PTR)Address & (Alignment - 1)) != 0)
-   {
-      ExRaiseStatus (STATUS_DATATYPE_MISALIGNMENT);
-   }
+        Last = (PCHAR)((ULONG_PTR)Address + Length - 1);
+        if ((ULONG_PTR)Last < (ULONG_PTR)Address ||
+            (ULONG_PTR)Last >= (ULONG_PTR)MmUserProbeAddress)
+        {
+            ExRaiseStatus (STATUS_ACCESS_VIOLATION);
+        }
 
-   Last = (CHAR*)((ULONG_PTR)Address + Length - 1);
-   if ((ULONG_PTR)Last < (ULONG_PTR)Address ||
-       (ULONG_PTR)Last >= (ULONG_PTR)MmUserProbeAddress)
-   {
-      ExRaiseStatus (STATUS_ACCESS_VIOLATION);
-   }
-
-   /* Check for accessible pages */
-   Current = (CHAR*)Address;
-   *Current = *Current;
-   Current = (PCHAR)((ULONG_PTR)PAGE_ROUND_DOWN(Current) + PAGE_SIZE);
-   while (Current <= Last)
-   {
-     *Current = *Current;
-     Current = (CHAR*)((ULONG_PTR)Current + PAGE_SIZE);
-   } 
+        /* Check for accessible pages, do *not* touch any memory outside of the
+           range!*/
+        Current = (volatile CHAR*)Address;
+        Last = (PCHAR)(PAGE_ROUND_DOWN(Last));
+        do
+        {
+            *Current = *Current;
+            Current = (volatile CHAR*)(PAGE_ROUND_DOWN(Current) + PAGE_SIZE);
+        } while (Current <= Last);
+    }
 }
 
 /* EOF */
diff --git a/reactos/w32api/include/ddk/winddk.h b/reactos/w32api/include/ddk/winddk.h
index eef60ca5e2b..8f5f16f553f 100644
--- a/reactos/w32api/include/ddk/winddk.h
+++ b/reactos/w32api/include/ddk/winddk.h
@@ -6738,7 +6738,7 @@ NTOSAPI
 VOID
 DDKAPI
 ProbeForWrite(
-  IN CONST VOID  *Address,
+  IN PVOID  Address,
   IN ULONG  Length,
   IN ULONG  Alignment);