Update DxePagingAudit to use FlatPageTableLib

Description

Now that FlatPageTableLib is available, update DxePagingAudit to use
it instead of needing to implement its own parsing logic.

- [x] Impacts functionality?
  - **Functionality** - Does the change ultimately impact how firmware functions?
  - Examples: Add a new library, publish a new PPI, update an algorithm, ...
- [ ] Impacts security?
  - **Security** - Does the change have a direct security impact on an application,
    flow, or firmware?
  - Examples: Crypto algorithm change, buffer overflow fix, parameter
    validation improvement, ...
- [x] Breaking change?
  - **Breaking change** - Will anyone consuming this change experience a break
    in build or boot behavior?
  - Examples: Add a new library class, move a module to a different repo, call
    a function in a new library class in a pre-existing module, ...
- [ ] Includes tests?
  - **Tests** - Does the change include any explicit test code?
  - Examples: Unit tests, integration tests, robot tests, ...
- [ ] Includes documentation?
  - **Documentation** - Does the change contain explicit documentation additions
    outside direct code modifications (and comments)?
  - Examples: Update readme file, add feature readme file, link to documentation
    on an a separate Web page, ...

How This Was Tested

Tested on Q35 and SBSA by adding a temporary test to check the output
of the Memory Attribute Protocol against the output of
FlatPageTableLib.

Integration Instructions

An instance of FlatPageTableLib will need to be added to platforms
which build the paging audit.

UefiTestingPkg/AuditTests/PagingAudit/UEFI/Dxe/App/DxePagingAuditTestApp.c

@@ -7,13 +7,18 @@ SPDX-License-Identifier: BSD-2-Clause-Patent
 
 **/
 
-#include "DxePagingAuditTestApp.h"
+#include "../../PagingAuditCommon.h"
 
 #include <Protocol/ShellParameters.h>
 #include <Protocol/Shell.h>
 #include <Protocol/SimpleFileSystem.h>
+#include <Protocol/MemoryProtectionSpecialRegionProtocol.h>
+#include <Protocol/MemoryProtectionDebug.h>
+
 #include <Library/FileHandleLib.h>
 #include <Library/DxeServicesTableLib.h>
+#include <Library/FlatPageTableLib.h>
+#include <Library/UnitTestLib.h>
 
 #define UNIT_TEST_APP_NAME     "Paging Audit Test"
 #define UNIT_TEST_APP_VERSION  "1"
@@ -31,6 +36,63 @@ IMAGE_RANGE_DESCRIPTOR            *mNonProtectedImageList      = NULL;
 UINTN                             mSpecialRegionCount          = 0;
 EFI_GCD_MEMORY_SPACE_DESCRIPTOR   *mMemorySpaceMap             = NULL;
 UINTN                             mMemorySpaceMapCount         = 0;
+PAGE_MAP                          mMap                         = { 0 };
+
+/**
+  Frees the entries in the mMap global.
+**/
+STATIC
+VOID
+EFIAPI
+FreePageTableMap (
+  IN UNIT_TEST_CONTEXT  Context
+  )
+{
+  if (mMap.Entries != NULL) {
+    FreePages (mMap.Entries, mMap.EntryPagesAllocated);
+  }
+}
+
+/**
+  Populate the global flat page table map.
+
+  @retval EFI_SUCCESS           The page table is parsed successfully.
+  @retval EFI_OUT_OF_RESOURCES  Failed to allocate memory for the page table map.
+  @retval EFI_INVALID_PARAMETER An error occurred while parsing the page table.
+**/
+STATIC
+UNIT_TEST_STATUS
+EFIAPI
+PopulatePageTableMap (
+  IN UNIT_TEST_CONTEXT  Context
+  )
+{
+  EFI_STATUS  Status;
+
+  Status = CreateFlatPageTable (&mMap);
+
+  while (Status == RETURN_BUFFER_TOO_SMALL) {
+    if ((mMap.Entries != NULL) && (mMap.EntryPagesAllocated > 0)) {
+      FreePages (mMap.Entries, mMap.EntryPagesAllocated);
+    }
+
+    mMap.EntryPagesAllocated = EFI_SIZE_TO_PAGES (mMap.EntryCount * sizeof (PAGE_MAP_ENTRY));
+    mMap.Entries             = AllocatePages (mMap.EntryPagesAllocated);
+
+    if (mMap.Entries == NULL) {
+      UT_LOG_ERROR ("Failed to allocate %d pages for page table map!\n", mMap.EntryPagesAllocated);
+      return UNIT_TEST_ERROR_PREREQUISITE_NOT_MET;
+    }
+
+    Status = CreateFlatPageTable (&mMap);
+  }
+
+  if ((Status != EFI_SUCCESS) && (mMap.Entries != NULL)) {
+    FreePageTableMap (Context);
+  }
+
+  return Status == EFI_SUCCESS ? UNIT_TEST_PASSED : UNIT_TEST_ERROR_PREREQUISITE_NOT_MET;
+}
 
 /**
   Populates the non protected image list global
@@ -114,6 +176,7 @@ GetSpecialRegions (
   @retval TRUE                  The region is allowed to be read/write/execute
   @retval FALSE                 The region is not allowed to be read/write/execute
 **/
+STATIC
 BOOLEAN
 CanRegionBeRWX (
   IN UINT64  Address,
@@ -179,6 +242,44 @@ CanRegionBeRWX (
   return FALSE;
 }
 
+/**
+  Check the page table for Read/Write/Execute regions.
+
+  @param[in] Context            Unit test context
+
+  @retval UNIT_TEST_PASSED      The unit test passed
+  @retval other                 The unit test failed
+
+**/
+UNIT_TEST_STATUS
+EFIAPI
+NoReadWriteExecute (
+  IN UNIT_TEST_CONTEXT  Context
+  )
+{
+  UINTN    Index;
+  BOOLEAN  FoundRWXAddress;
+
+  UT_ASSERT_NOT_NULL (mMap.Entries);
+  UT_ASSERT_NOT_EQUAL (mMap.EntryCount, 0);
+
+  Index           = 0;
+  FoundRWXAddress = FALSE;
+
+  for ( ; Index < mMap.EntryCount; Index++) {
+    if (IsPageExecutable (mMap.Entries[Index].PageEntry) && IsPageReadable (mMap.Entries[Index].PageEntry) && IsPageWritable (mMap.Entries[Index].PageEntry)) {
+      if (!CanRegionBeRWX (mMap.Entries[Index].LinearAddress, mMap.Entries[Index].Length)) {
+        UT_LOG_ERROR ("Memory Range 0x%llx-0x%llx is Read/Write/Execute\n", mMap.Entries[Index].LinearAddress, mMap.Entries[Index].LinearAddress + mMap.Entries[Index].Length);
+        FoundRWXAddress = TRUE;
+      }
+    }
+  }
+
+  UT_ASSERT_FALSE (FoundRWXAddress);
+
+  return UNIT_TEST_PASSED;
+}
+
 /**
 
  Locates and opens the SFS volume containing the application and, if successful, returns an
@@ -401,7 +502,7 @@ DxePagingAuditTestAppEntryPoint (
       DEBUG ((DEBUG_ERROR, "%a - Unable to fetch the GCD memory map. Test results may be inaccurate. Status: %r\n", __FUNCTION__, Status));
     }
 
-    AddTestCase (Misc, "No pages can be read,write,execute", "Security.Misc.NoReadWriteExecute", NoReadWriteExecute, NULL, NULL, NULL);
+    AddTestCase (Misc, "No pages can be read,write,execute", "Security.Misc.NoReadWriteExecute", NoReadWriteExecute, PopulatePageTableMap, FreePageTableMap, NULL);
 
     //
     // Execute the tests.