Revert "Always set WP in CR0."

This reverts SVN r18960 / git commit
8e496a7abc.

The patch series had been fully reviewed on edk2-devel, but it got
committed as a single squashed patch. Revert it for now.

Link: http://thread.gmane.org/gmane.comp.bios.edk2.devel/4951
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Laszlo Ersek <lersek@redhat.com>

git-svn-id: https://svn.code.sf.net/p/edk2/code/trunk/edk2@18977 6f19259b-4bc3-4df7-8a09-765794883524

UefiCpuPkg/PiSmmCpuDxeSmm/X64/PageTbl.c

@@ -127,7 +127,7 @@ SmmInitPageTable (
   // Fill Page-Table-Level4 (PML4) entry
   //
   PTEntry = (UINT64*)(UINTN)(Pages - EFI_PAGES_TO_SIZE (PAGE_TABLE_PAGES + 1));
-  *PTEntry = Pages + PAGE_ATTRIBUTE_BITS;
+  *PTEntry = Pages + IA32_PG_P;
   ZeroMem (PTEntry + 1, EFI_PAGE_SIZE - sizeof (*PTEntry));
   //
   // Set sub-entries number
@@ -591,7 +591,7 @@ SmiDefaultPFHandler (
         //
         // If the entry is not present, allocate one page from page pool for it
         //
-        PageTable[PTIndex] = AllocPage () | PAGE_ATTRIBUTE_BITS;
+        PageTable[PTIndex] = AllocPage () | IA32_PG_RW | IA32_PG_P;
       } else {
         //
         // Save the upper entry address
@@ -621,7 +621,7 @@ SmiDefaultPFHandler (
     // Fill the new entry
     //
     PageTable[PTIndex] = (PFAddress & gPhyMask & ~((1ull << EndBit) - 1)) |
-                         PageAttribute | IA32_PG_A | PAGE_ATTRIBUTE_BITS;
+                         PageAttribute | IA32_PG_A | IA32_PG_RW | IA32_PG_P;
     if (UpperEntry != NULL) {
       SetSubEntriesNum (UpperEntry, GetSubEntriesNum (UpperEntry) + 1);
     }