ArmPkg/Mmu: Increase PageLevel when table found at the targeted level

Below code has bug since *BlockEntrySize and *TableLevel are not
updated accordingly:

if (IndexLevel == PageLevel) {
  // And get the appropriate BlockEntry at the next level
  BlockEntry = (UINT64*)TT_GET_ENTRY_FOR_ADDRESS (TranslationTable, \
      IndexLevel + 1, RegionStart);

  // Set the last block for this new table
  *LastBlockEntry = TT_LAST_BLOCK_ADDRESS(TranslationTable, \
      TT_ENTRY_COUNT);
}

Also it doesn't check recursively to get the last level, e.g. the
initial PageLevel is 1 and we already have level 2 and 3 tables at
this address.

What's more, *LastBlockEntry was not updated when we get a table and
IndexLevel != PageLevel.

So we reorganize the sequence, only updating TranslationTable,
PageLevel and BlockEntry in the loop, and setting the other output
parameters with the final PageLevel before returning.

And LastBlockEntry is only an OUT parameter.

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Heyi Guo <heyi.guo@linaro.org>
Cc: Leif Lindholm <leif.lindholm@linaro.org>
Reviewed-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>

git-svn-id: https://svn.code.sf.net/p/edk2/code/trunk/edk2@18424 6f19259b-4bc3-4df7-8a09-765794883524

ArmPkg/Library/ArmLib/AArch64/AArch64Mmu.c

@@ -244,7 +244,7 @@ GetBlockEntryListFromAddress (
   IN  UINT64        RegionStart,
   OUT UINTN        *TableLevel,
   IN OUT UINT64    *BlockEntrySize,
-  IN OUT UINT64   **LastBlockEntry
+  OUT UINT64      **LastBlockEntry
   )
 {
   UINTN   RootTableLevel;
@@ -282,14 +282,9 @@ GetBlockEntryListFromAddress (
     return NULL;
   }
 
-  //
-  // Calculate LastBlockEntry from T0SZ - this is the last block entry of the root Translation table
-  //
   T0SZ = ArmGetTCR () & TCR_T0SZ_MASK;
   // Get the Table info from T0SZ
   GetRootTranslationTableInfo (T0SZ, &RootTableLevel, &RootTableEntryCount);
-  // The last block of the root table depends on the number of entry in this table
-  *LastBlockEntry = TT_LAST_BLOCK_ADDRESS(RootTable, RootTableEntryCount);
 
   // If the start address is 0x0 then we use the size of the region to identify the alignment
   if (RegionStart == 0) {
@@ -311,12 +306,6 @@ GetBlockEntryListFromAddress (
     PageLevel++;
   }
 
-  // Expose the found PageLevel to the caller
-  *TableLevel = PageLevel;
-
-  // Now, we have the Table Level we can get the Block Size associated to this table
-  *BlockEntrySize = TT_BLOCK_ENTRY_SIZE_AT_LEVEL (PageLevel);
-
   //
   // Get the Table Descriptor for the corresponding PageLevel. We need to decompose RegionStart to get appropriate entries
   //
@@ -329,13 +318,10 @@ GetBlockEntryListFromAddress (
       // Go to the next table
       TranslationTable = (UINT64*)(*BlockEntry & TT_ADDRESS_MASK_DESCRIPTION_TABLE);
 
-      // If we are at the last level then update the output
+      // If we are at the last level then update the last level to next level
       if (IndexLevel == PageLevel) {
-        // And get the appropriate BlockEntry at the next level
+        // Enter the next level
-        BlockEntry = (UINT64*)TT_GET_ENTRY_FOR_ADDRESS (TranslationTable, IndexLevel + 1, RegionStart);
+        PageLevel++;
-
-        // Set the last block for this new table
-        *LastBlockEntry = TT_LAST_BLOCK_ADDRESS(TranslationTable, TT_ENTRY_COUNT);
       }
     } else if ((*BlockEntry & TT_TYPE_MASK) == TT_TYPE_BLOCK_ENTRY) {
       // If we are not at the last level then we need to split this BlockEntry
@@ -383,11 +369,6 @@ GetBlockEntryListFromAddress (
 
         // Fill the BlockEntry with the new TranslationTable
         *BlockEntry = ((UINTN)TranslationTable & TT_ADDRESS_MASK_DESCRIPTION_TABLE) | TableAttributes | TT_TYPE_TABLE_ENTRY;
-        // Update the last block entry with the newly created translation table
-        *LastBlockEntry = TT_LAST_BLOCK_ADDRESS(TranslationTable, TT_ENTRY_COUNT);
-
-        // Block Entry points at the beginning of the Translation Table
-        BlockEntry = TranslationTable;
       }
     } else {
       if (IndexLevel != PageLevel) {
@@ -405,17 +386,21 @@ GetBlockEntryListFromAddress (
 
         // Fill the new BlockEntry with the TranslationTable
         *BlockEntry = ((UINTN)TranslationTable & TT_ADDRESS_MASK_DESCRIPTION_TABLE) | TT_TYPE_TABLE_ENTRY;
-        // Update the last block entry with the newly created translation table
-        *LastBlockEntry = TT_LAST_BLOCK_ADDRESS(TranslationTable, TT_ENTRY_COUNT);
-      } else {
-        //
-        // Case when the new region is part of an existing page table
-        //
-        *LastBlockEntry = TT_LAST_BLOCK_ADDRESS(TranslationTable, TT_ENTRY_COUNT);
       }
     }
   }
 
+  // Expose the found PageLevel to the caller
+  *TableLevel = PageLevel;
+
+  // Now, we have the Table Level we can get the Block Size associated to this table
+  *BlockEntrySize = TT_BLOCK_ENTRY_SIZE_AT_LEVEL (PageLevel);
+
+  // The last block of the root table depends on the number of entry in this table,
+  // otherwise it is always the (TT_ENTRY_COUNT - 1)th entry in the table.
+  *LastBlockEntry = TT_LAST_BLOCK_ADDRESS(TranslationTable,
+      (PageLevel == RootTableLevel) ? RootTableEntryCount : TT_ENTRY_COUNT);
+
   return BlockEntry;
 }