UefiCpuPkg: Fix typos in comments

[mirror_edk2.git] / UefiCpuPkg / Library / MtrrLib / MtrrLib.c

diff --git a/UefiCpuPkg/Library/MtrrLib/MtrrLib.c b/UefiCpuPkg/Library/MtrrLib/MtrrLib.c
index 06a361bd84334cba939a3e4925a0f92fa4f51a76..7783b63d8267e222e2e060d2de5f43b88628e1c1 100644 (file)
--- a/UefiCpuPkg/Library/MtrrLib/MtrrLib.c
+++ b/UefiCpuPkg/Library/MtrrLib/MtrrLib.c
@@ -1,6 +1,10 @@
 /** @file\r
   MTRR setting library\r
 \r
+  @par Note: \r
+    Most of services in this library instance are suggested to be invoked by BSP only,\r
+    except for MtrrSetAllMtrrs() which is used to sync BSP's MTRR setting to APs.\r
+\r
   Copyright (c) 2008 - 2016, Intel Corporation. All rights reserved.<BR>\r
   This program and the accompanying materials\r
   are licensed and made available under the terms and conditions of the BSD License\r
@@ -20,6 +24,9 @@
 #include <Library/BaseMemoryLib.h>\r
 #include <Library/DebugLib.h>\r
 \r
+#define OR_SEED      0x0101010101010101ull\r
+#define CLEAR_SEED   0xFFFFFFFFFFFFFFFFull\r
+\r
 //\r
 // Context to save and restore when MTRRs are programmed\r
 //\r
@@ -459,13 +466,15 @@ ProgramFixedMtrr (
   )\r
 {\r
   UINT32  MsrNum;\r
-  UINT32  ByteShift;\r
+  UINT32  LeftByteShift;\r
+  UINT32  RightByteShift;\r
   UINT64  OrMask;\r
   UINT64  ClearMask;\r
+  UINT64  SubLength;\r
 \r
-  OrMask    = 0;\r
-  ClearMask = 0;\r
-\r
+  //\r
+  // Find the fixed MTRR index to be programmed\r
+  //\r
   for (MsrNum = *LastMsrNum + 1; MsrNum < MTRR_NUMBER_OF_FIXED_MTRR; MsrNum++) {\r
     if ((*Base >= mMtrrLibFixedMtrrTable[MsrNum].BaseAddress) &&\r
         (*Base <\r
@@ -484,30 +493,57 @@ ProgramFixedMtrr (
   }\r
 \r
   //\r
-  // We found the fixed MTRR to be programmed\r
+  // Find the begin offset in fixed MTRR and calculate byte offset of left shift\r
   //\r
-  ByteShift = ((UINT32)*Base - mMtrrLibFixedMtrrTable[MsrNum].BaseAddress)\r
+  LeftByteShift = ((UINT32)*Base - mMtrrLibFixedMtrrTable[MsrNum].BaseAddress)\r
                / mMtrrLibFixedMtrrTable[MsrNum].Length;\r
 \r
-  if (ByteShift >= 8) {\r
+  if (LeftByteShift >= 8) {\r
     return RETURN_UNSUPPORTED;\r
   }\r
 \r
-  for (\r
-        ;\r
-        ((ByteShift < 8) && (*Length >= mMtrrLibFixedMtrrTable[MsrNum].Length));\r
-        ByteShift++\r
-      ) {\r
-    OrMask |= LShiftU64 ((UINT64) MemoryCacheType, (UINT32) (ByteShift * 8));\r
-    ClearMask |= LShiftU64 ((UINT64) 0xFF, (UINT32) (ByteShift * 8));\r
-    *Length -= mMtrrLibFixedMtrrTable[MsrNum].Length;\r
-    *Base += mMtrrLibFixedMtrrTable[MsrNum].Length;\r
+  //\r
+  // Find the end offset in fixed MTRR and calculate byte offset of right shift\r
+  //\r
+  SubLength = mMtrrLibFixedMtrrTable[MsrNum].Length * (8 - LeftByteShift);\r
+  if (*Length >= SubLength) {\r
+    RightByteShift = 0;\r
+  } else {\r
+    RightByteShift = 8 - LeftByteShift -\r
+                (UINT32)(*Length) / mMtrrLibFixedMtrrTable[MsrNum].Length;\r
+    if ((LeftByteShift >= 8) ||\r
+        (((UINT32)(*Length) % mMtrrLibFixedMtrrTable[MsrNum].Length) != 0)\r
+        ) {\r
+      return RETURN_UNSUPPORTED;\r
+    }\r
+    //\r
+    // Update SubLength by actual length\r
+    //\r
+    SubLength = *Length;\r
+  }\r
+\r
+  ClearMask = CLEAR_SEED;\r
+  OrMask    = MultU64x32 (OR_SEED, (UINT32)MemoryCacheType);\r
+\r
+  if (LeftByteShift != 0) {\r
+    //\r
+    // Clear the low bits by LeftByteShift\r
+    //\r
+    ClearMask &= LShiftU64 (ClearMask, LeftByteShift * 8);\r
+    OrMask    &= LShiftU64 (OrMask, LeftByteShift * 8);\r
   }\r
 \r
-  if (ByteShift < 8 && (*Length != 0)) {\r
-    return RETURN_UNSUPPORTED;\r
+  if (RightByteShift != 0) {\r
+    //\r
+    // Clear the high bits by RightByteShift\r
+    //\r
+    ClearMask &= RShiftU64 (ClearMask, RightByteShift * 8);\r
+    OrMask    &= RShiftU64 (OrMask, RightByteShift * 8);\r
   }\r
 \r
+  *Length -= SubLength;\r
+  *Base   += SubLength;\r
+\r
   *LastMsrNum      = MsrNum;\r
   *ReturnClearMask = ClearMask;\r
   *ReturnOrMask    = OrMask;\r
@@ -570,7 +606,7 @@ MtrrGetMemoryAttributeInVariableMtrrWorker (
   @param[in]   MtrrValidAddressMask  The valid address mask for MTRR\r
   @param[out]  VariableMtrr          The array to shadow variable MTRRs content\r
 \r
-  @return                       The return value of this paramter indicates the\r
+  @return                       The return value of this parameter indicates the\r
                                 number of MTRRs which has been used.\r
 \r
 **/\r
@@ -2071,8 +2107,6 @@ MtrrSetAllMtrrs (
 \r
   PostMtrrChangeEnableCache (&MtrrContext);\r
 \r
-  MtrrDebugPrintAllMtrrs ();\r
-\r
   return MtrrSetting;\r
 }\r
 \r