[ros-diffs] [ion] 57229: [NTOSKRNL]: Fix a stupid bug in MiProtectVirtualMemory which was causing empty PTEs whose protection was being set to remain zero PTEs, instead of demand-zero PTEs, but still acquire a...

Author: ion
Date: Mon Sep  3 16:29:31 2012
New Revision: 57229

URL: http://svn.reactos.org/svn/reactos?rev=57229&view=rev
Log:
[NTOSKRNL]: Fix a stupid bug in MiProtectVirtualMemory which was causing empty PTEs whose
protection was being set to remain zero PTEs, instead of demand-zero PTEs, but still
acquire a page table reference. When they were later touched in the page fault code, and
made into demand-zero PTEs, they'd get referenced again, thus Aleksey hacked away all
the referencing code to work around this (causing PDEs to disappear...)
[NTOSKRNL]: Restore the page table reference counting mechanism, and put it in a macro to
be cleaner. Also use macros for testing PD boundaries, instead of math-by-hand.

Modified:
    trunk/reactos/ntoskrnl/mm/ARM3/miarm.h
    trunk/reactos/ntoskrnl/mm/ARM3/pagfault.c
    trunk/reactos/ntoskrnl/mm/ARM3/section.c
    trunk/reactos/ntoskrnl/mm/ARM3/virtual.c

Modified: trunk/reactos/ntoskrnl/mm/ARM3/miarm.h
URL:
http://svn.reactos.org/svn/reactos/trunk/reactos/ntoskrnl/mm/ARM3/miarm.h?r…
==============================================================================
--- trunk/reactos/ntoskrnl/mm/ARM3/miarm.h [iso-8859-1] (original)
+++ trunk/reactos/ntoskrnl/mm/ARM3/miarm.h [iso-8859-1] Mon Sep  3 16:29:31 2012
@@ -1619,6 +1619,41 @@
     }
 }
 
+FORCEINLINE
+VOID
+MiIncrementPageTableReferences(IN PVOID Address)
+{
+    PUSHORT RefCount;
+
+    RefCount = &MmWorkingSetList->UsedPageTableEntries[MiGetPdeOffset(Address)];
+
+    *RefCount += 1;
+    ASSERT(*RefCount <= PTE_PER_PAGE);
+}
+
+FORCEINLINE
+VOID
+MiDecrementPageTableReferences(IN PVOID Address)
+{
+    PUSHORT RefCount;
+
+    RefCount = &MmWorkingSetList->UsedPageTableEntries[MiGetPdeOffset(Address)];
+
+    *RefCount -= 1;
+    ASSERT(*RefCount < PTE_PER_PAGE);
+}
+
+FORCEINLINE
+USHORT
+MiQueryPageTableReferences(IN PVOID Address)
+{
+    PUSHORT RefCount;
+
+    RefCount = &MmWorkingSetList->UsedPageTableEntries[MiGetPdeOffset(Address)];
+
+    return *RefCount;
+}
+
 BOOLEAN
 NTAPI
 MmArmInitSystem(

Modified: trunk/reactos/ntoskrnl/mm/ARM3/pagfault.c
URL:
http://svn.reactos.org/svn/reactos/trunk/reactos/ntoskrnl/mm/ARM3/pagfault.…
==============================================================================
--- trunk/reactos/ntoskrnl/mm/ARM3/pagfault.c [iso-8859-1] (original)
+++ trunk/reactos/ntoskrnl/mm/ARM3/pagfault.c [iso-8859-1] Mon Sep  3 16:29:31 2012
@@ -1684,8 +1684,7 @@
         if (Address <= MM_HIGHEST_USER_ADDRESS)
         {
             /* Add an additional page table reference */
-            MmWorkingSetList->UsedPageTableEntries[MiGetPdeOffset(Address)]++;
-            ASSERT(MmWorkingSetList->UsedPageTableEntries[MiGetPdeOffset(Address)]
<= PTE_COUNT);
+            MiIncrementPageTableReferences(Address);
         }
 
         /* Did we get a prototype PTE back? */

Modified: trunk/reactos/ntoskrnl/mm/ARM3/section.c
URL:
http://svn.reactos.org/svn/reactos/trunk/reactos/ntoskrnl/mm/ARM3/section.c…
==============================================================================
--- trunk/reactos/ntoskrnl/mm/ARM3/section.c [iso-8859-1] (original)
+++ trunk/reactos/ntoskrnl/mm/ARM3/section.c [iso-8859-1] Mon Sep  3 16:29:31 2012
@@ -1821,7 +1821,6 @@
     PMMPDE PointerPde;
     PMMPFN Pfn1;
     ULONG ProtectionMask, QuotaCharge = 0;
-    PUSHORT UsedPageTableEntries;
     PETHREAD Thread = PsGetCurrentThread();
     PAGED_CODE();
 
@@ -1914,9 +1913,7 @@
             // This used to be a zero PTE and it no longer is, so we must add a
             // reference to the pagetable.
             //
-            UsedPageTableEntries =
&MmWorkingSetList->UsedPageTableEntries[MiGetPdeOffset(MiPteToAddress(PointerPte))];
-            (*UsedPageTableEntries)++;
-            ASSERT((*UsedPageTableEntries) <= PTE_COUNT);
+            MiIncrementPageTableReferences(MiPteToAddress(PointerPte));
 
             //
             // Create the demand-zero prototype PTE

Modified: trunk/reactos/ntoskrnl/mm/ARM3/virtual.c
URL:
http://svn.reactos.org/svn/reactos/trunk/reactos/ntoskrnl/mm/ARM3/virtual.c…
==============================================================================
--- trunk/reactos/ntoskrnl/mm/ARM3/virtual.c [iso-8859-1] (original)
+++ trunk/reactos/ntoskrnl/mm/ARM3/virtual.c [iso-8859-1] Mon Sep  3 16:29:31 2012
@@ -589,10 +589,8 @@
             TempPte = *PointerPte;
             if (TempPte.u.Long)
             {
-                DPRINT("Decrement used PTEs by address: %lx\n", Va);
-                (*UsedPageTableEntries)--;
+                *UsedPageTableEntries -= 1;
                 ASSERT((*UsedPageTableEntries) < PTE_COUNT);
-                DPRINT("Refs: %lx\n", (*UsedPageTableEntries));
 
                 /* Check if the PTE is actually mapped in */
                 if (TempPte.u.Long & 0xFFFFFC01)
@@ -653,14 +651,10 @@
         /* The PDE should still be valid at this point */
         ASSERT(PointerPde->u.Hard.Valid == 1);
 
-        DPRINT("Should check if handles for: %p are zero (PDE: %lx)\n", Va,
PointerPde->u.Hard.PageFrameNumber);
-        if (!(*UsedPageTableEntries))
-        {
-            DPRINT("They are!\n");
+        if (*UsedPageTableEntries == 0)
+        {
             if (PointerPde->u.Long != 0)
             {
-                DPRINT("PDE active: %lx in %16s\n",
PointerPde->u.Hard.PageFrameNumber, CurrentProcess->ImageFileName);
-
                 /* Delete the PTE proper */
                 MiDeletePte(PointerPde,
                             MiPteToAddress(PointerPde),
@@ -1880,7 +1874,6 @@
     ULONG_PTR StartingAddress, EndingAddress;
     PMMPTE PointerPde, PointerPte, LastPte;
     MMPTE PteContents;
-    //PUSHORT UsedPageTableEntries;
     PMMPFN Pfn1;
     ULONG ProtectionMask, OldProtect;
     BOOLEAN Committed;
@@ -2050,24 +2043,23 @@
         while (PointerPte <= LastPte)
         {
             /* Check if we've crossed a PDE boundary and make the new PDE valid too
*/
-            if ((((ULONG_PTR)PointerPte) & (SYSTEM_PD_SIZE - 1)) == 0)
+            if (MiIsPteOnPdeBoundary(PointerPte))
             {
                 PointerPde = MiAddressToPte(PointerPte);
                 MiMakePdeExistAndMakeValid(PointerPde, Process, MM_NOIRQL);
             }
 
-            /* Capture the PTE and see what we're dealing with */
+            /* Capture the PTE and check if it was empty */
             PteContents = *PointerPte;
             if (PteContents.u.Long == 0)
             {
                 /* This used to be a zero PTE and it no longer is, so we must add a
                    reference to the pagetable. */
-                //UsedPageTableEntries =
&MmWorkingSetList->UsedPageTableEntries[MiGetPdeOffset(MiPteToAddress(PointerPte))];
-                //(*UsedPageTableEntries)++;
-                //ASSERT((*UsedPageTableEntries) <= PTE_COUNT);
-                DPRINT1("HACK: Not increasing UsedPageTableEntries count!\n");
-            }
-            else if (PteContents.u.Hard.Valid == 1)
+                MiIncrementPageTableReferences(MiPteToAddress(PointerPte));
+            }
+
+            /* Check what kind of PTE we are dealing with */
+            if (PteContents.u.Hard.Valid == 1)
             {
                 /* Get the PFN entry */
                 Pfn1 = MiGetPfnEntry(PFN_FROM_PTE(&PteContents));
@@ -2080,8 +2072,11 @@
                     (NewAccessProtection & PAGE_GUARD))
                 {
                     /* The page should be in the WS and we should make it transition now
*/
-                    UNIMPLEMENTED;
-                    //continue;
+                    DPRINT1("Making valid page invalid is not yet
supported!\n");
+                    Status = STATUS_NOT_IMPLEMENTED;
+                    /* Unlock the working set */
+                    MiUnlockProcessWorkingSetUnsafe(Process, Thread);
+                    goto FailPath;
                 }
 
                 /* Write the protection mask and write it with a TLB flush */
@@ -2270,7 +2265,6 @@
     ULONG PteCount = 0;
     PMMPFN Pfn1;
     MMPTE PteContents;
-    PUSHORT UsedPageTableEntries;
     PETHREAD CurrentThread = PsGetCurrentThread();
 
     //
@@ -2292,7 +2286,7 @@
         //
         // Check if we've crossed a PDE boundary
         //
-        if ((((ULONG_PTR)PointerPte) & (SYSTEM_PD_SIZE - 1)) == 0)
+        if (MiIsPteOnPdeBoundary(PointerPte))
         {
             //
             // Get the new PDE and flush the valid PTEs we had built up until
@@ -2383,9 +2377,7 @@
             // This used to be a zero PTE and it no longer is, so we must add a
             // reference to the pagetable.
             //
-            UsedPageTableEntries =
&MmWorkingSetList->UsedPageTableEntries[MiGetPdeOffset(StartingAddress)];
-            (*UsedPageTableEntries)++;
-            ASSERT((*UsedPageTableEntries) <= PTE_COUNT);
+            MiIncrementPageTableReferences(StartingAddress);
 
             //
             // Next, we account for decommitted PTEs and make the PTE as such
@@ -3648,7 +3640,6 @@
     PMEMORY_AREA MemoryArea;
     PFN_NUMBER PageCount;
     PMMVAD Vad, FoundVad;
-    PUSHORT UsedPageTableEntries;
     NTSTATUS Status;
     PMMSUPPORT AddressSpace;
     PVOID PBaseAddress;
@@ -4268,7 +4259,7 @@
         //
         // Have we crossed into a new page table?
         //
-        if (!(((ULONG_PTR)PointerPte) & (SYSTEM_PD_SIZE - 1)))
+        if (MiIsPteOnPdeBoundary(PointerPte))
         {
             //
             // Get the PDE and now make it valid too
@@ -4286,9 +4277,7 @@
             // First increment the count of pages in the page table for this
             // process
             //
-            UsedPageTableEntries =
&MmWorkingSetList->UsedPageTableEntries[MiGetPdeOffset(MiPteToAddress(PointerPte))];
-            (*UsedPageTableEntries)++;
-            ASSERT((*UsedPageTableEntries) <= PTE_COUNT);
+            MiIncrementPageTableReferences(MiPteToAddress(PointerPte));
 
             //
             // And now write the invalid demand-zero PTE as requested