ArmPkg/ArmMmuLib: deobfuscate GetRootTranslationTableInfo ()

[mirror_edk2.git] / ArmPkg / Library / ArmMmuLib / AArch64 / ArmMmuLibCore.c

diff --git a/ArmPkg/Library/ArmMmuLib/AArch64/ArmMmuLibCore.c b/ArmPkg/Library/ArmMmuLib/AArch64/ArmMmuLibCore.c
index 6e05e6085011a4bbbc8dd45d03173bc69d001532..84a689af7c8aef4f969d1a27c0084f6dfc5e9631 100644 (file)
--- a/ArmPkg/Library/ArmMmuLib/AArch64/ArmMmuLibCore.c
+++ b/ArmPkg/Library/ArmMmuLib/AArch64/ArmMmuLibCore.c
@@ -121,20 +121,8 @@ GcdAttributeToArmAttribute (
   }\r
 }\r
 \r
-// Describe the T0SZ values for each translation table level\r
-typedef struct {\r
-  UINTN     MinT0SZ;\r
-  UINTN     MaxT0SZ;\r
-  UINTN     LargestT0SZ; // Generally (MaxT0SZ == LargestT0SZ) but at the Level3 Table\r
-                         // the MaxT0SZ is not at the boundary of the table\r
-} T0SZ_DESCRIPTION_PER_LEVEL;\r
-\r
-// Map table for the corresponding Level of Table\r
-STATIC CONST T0SZ_DESCRIPTION_PER_LEVEL T0SZPerTableLevel[] = {\r
-    { 16, 24, 24 }, // Table Level 0\r
-    { 25, 33, 33 }, // Table Level 1\r
-    { 34, 39, 42 }  // Table Level 2\r
-};\r
+#define MIN_T0SZ        16\r
+#define BITS_PER_LEVEL  9\r
 \r
 VOID\r
 GetRootTranslationTableInfo (\r
@@ -143,28 +131,13 @@ GetRootTranslationTableInfo (
   OUT UINTN   *TableEntryCount\r
   )\r
 {\r
-  UINTN Index;\r
-\r
-  // Identify the level of the root table from the given T0SZ\r
-  for (Index = 0; Index < sizeof (T0SZPerTableLevel) / sizeof (T0SZ_DESCRIPTION_PER_LEVEL); Index++) {\r
-    if (T0SZ <= T0SZPerTableLevel[Index].MaxT0SZ) {\r
-      break;\r
-    }\r
-  }\r
-\r
-  // If we have not found the corresponding maximum T0SZ then we use the last one\r
-  if (Index == sizeof (T0SZPerTableLevel) / sizeof (T0SZ_DESCRIPTION_PER_LEVEL)) {\r
-    Index--;\r
-  }\r
-\r
   // Get the level of the root table\r
   if (TableLevel) {\r
-    *TableLevel = Index;\r
+    *TableLevel = (T0SZ - MIN_T0SZ) / BITS_PER_LEVEL;\r
   }\r
 \r
-  // The Size of the Table is 2^(T0SZ-LargestT0SZ)\r
   if (TableEntryCount) {\r
-    *TableEntryCount = 1 << (T0SZPerTableLevel[Index].LargestT0SZ - T0SZ + 1);\r
+    *TableEntryCount = 1UL << (BITS_PER_LEVEL - (T0SZ - MIN_T0SZ) % BITS_PER_LEVEL);\r
   }\r
 }\r
 \r