[mirror_edk2.git] / UefiCpuPkg / Library / MpInitLib / Microcode.c

/** @file\r
  Implementation of loading microcode on processors.\r
\r
  Copyright (c) 2015 - 2020, Intel Corporation. All rights reserved.<BR>\r
  SPDX-License-Identifier: BSD-2-Clause-Patent\r
\r
**/\r
\r
#include "MpLib.h"\r
\r
/**\r
  Get microcode update signature of currently loaded microcode update.\r
\r
  @return  Microcode signature.\r
**/\r
UINT32\r
GetCurrentMicrocodeSignature (\r
  VOID\r
  )\r
{\r
  MSR_IA32_BIOS_SIGN_ID_REGISTER   BiosSignIdMsr;\r
\r
  AsmWriteMsr64 (MSR_IA32_BIOS_SIGN_ID, 0);\r
  AsmCpuid (CPUID_VERSION_INFO, NULL, NULL, NULL, NULL);\r
  BiosSignIdMsr.Uint64 = AsmReadMsr64 (MSR_IA32_BIOS_SIGN_ID);\r
  return BiosSignIdMsr.Bits.MicrocodeUpdateSignature;\r
}\r
\r
/**\r
  Detect whether specified processor can find matching microcode patch and load it.\r
\r
  Microcode Payload as the following format:\r
  +----------------------------------------+------------------+\r
  |          CPU_MICROCODE_HEADER          |                  |\r
  +----------------------------------------+  CheckSum Part1  |\r
  |            Microcode Binary            |                  |\r
  +----------------------------------------+------------------+\r
  |  CPU_MICROCODE_EXTENDED_TABLE_HEADER   |                  |\r
  +----------------------------------------+  CheckSum Part2  |\r
  |      CPU_MICROCODE_EXTENDED_TABLE      |                  |\r
  |                   ...                  |                  |\r
  +----------------------------------------+------------------+\r
\r
  There may by multiple CPU_MICROCODE_EXTENDED_TABLE in this format.\r
  The count of CPU_MICROCODE_EXTENDED_TABLE is indicated by ExtendedSignatureCount\r
  of CPU_MICROCODE_EXTENDED_TABLE_HEADER structure.\r
\r
  When we are trying to verify the CheckSum32 with extended table.\r
  We should use the fields of exnteded table to replace the corresponding\r
  fields in CPU_MICROCODE_HEADER structure, and recalculate the\r
  CheckSum32 with CPU_MICROCODE_HEADER + Microcode Binary. We named\r
  it as CheckSum Part3.\r
\r
  The CheckSum Part2 is used to verify the CPU_MICROCODE_EXTENDED_TABLE_HEADER\r
  and CPU_MICROCODE_EXTENDED_TABLE parts. We should make sure CheckSum Part2\r
  is correct before we are going to verify each CPU_MICROCODE_EXTENDED_TABLE.\r
\r
  Only ProcessorSignature, ProcessorFlag and CheckSum are different between\r
  CheckSum Part1 and CheckSum Part3. To avoid multiple computing CheckSum Part3.\r
  Save an in-complete CheckSum32 from CheckSum Part1 for common parts.\r
  When we are going to calculate CheckSum32, just should use the corresponding part\r
  of the ProcessorSignature, ProcessorFlag and CheckSum with in-complete CheckSum32.\r
\r
  Notes: CheckSum32 is not a strong verification.\r
         It does not guarantee that the data has not been modified.\r
         CPU has its own mechanism to verify Microcode Binary part.\r
\r
  @param[in]  CpuMpData        The pointer to CPU MP Data structure.\r
  @param[in]  ProcessorNumber  The handle number of the processor. The range is\r
                               from 0 to the total number of logical processors\r
                               minus 1.\r
**/\r
VOID\r
MicrocodeDetect (\r
  IN CPU_MP_DATA             *CpuMpData,\r
  IN UINTN                   ProcessorNumber\r
  )\r
{\r
  UINT32                                  ExtendedTableLength;\r
  UINT32                                  ExtendedTableCount;\r
  CPU_MICROCODE_EXTENDED_TABLE            *ExtendedTable;\r
  CPU_MICROCODE_EXTENDED_TABLE_HEADER     *ExtendedTableHeader;\r
  CPU_MICROCODE_HEADER                    *MicrocodeEntryPoint;\r
  UINTN                                   MicrocodeEnd;\r
  UINTN                                   Index;\r
  UINT8                                   PlatformId;\r
  CPUID_VERSION_INFO_EAX                  Eax;\r
  CPU_AP_DATA                             *CpuData;\r
  UINT32                                  CurrentRevision;\r
  UINT32                                  LatestRevision;\r
  UINTN                                   TotalSize;\r
  UINT32                                  CheckSum32;\r
  UINT32                                  InCompleteCheckSum32;\r
  BOOLEAN                                 CorrectMicrocode;\r
  VOID                                    *MicrocodeData;\r
  UINT32                                  ThreadId;\r
  BOOLEAN                                 IsBspCallIn;\r
\r
  if (CpuMpData->MicrocodePatchRegionSize == 0) {\r
    //\r
    // There is no microcode patches\r
    //\r
    return;\r
  }\r
\r
  CurrentRevision = GetCurrentMicrocodeSignature ();\r
  IsBspCallIn     = (ProcessorNumber == (UINTN)CpuMpData->BspNumber) ? TRUE : FALSE;\r
\r
  GetProcessorLocationByApicId (GetInitialApicId (), NULL, NULL, &ThreadId);\r
  if (ThreadId != 0) {\r
    //\r
    // Skip loading microcode if it is not the first thread in one core.\r
    //\r
    return;\r
  }\r
\r
  ExtendedTableLength = 0;\r
  Eax.Uint32 = CpuMpData->CpuData[ProcessorNumber].ProcessorSignature;\r
  PlatformId = CpuMpData->CpuData[ProcessorNumber].PlatformId;\r
\r
  //\r
  // Check whether AP has same processor with BSP.\r
  // If yes, direct use microcode info saved by BSP.\r
  //\r
  if (!IsBspCallIn) {\r
    //\r
    // Get the CPU data for BSP\r
    //\r
    CpuData = &(CpuMpData->CpuData[CpuMpData->BspNumber]);\r
    if ((CpuData->ProcessorSignature == Eax.Uint32) &&\r
        (CpuData->PlatformId == PlatformId) &&\r
        (CpuData->MicrocodeEntryAddr != 0)) {\r
      MicrocodeEntryPoint = (CPU_MICROCODE_HEADER *)(UINTN) CpuData->MicrocodeEntryAddr;\r
      MicrocodeData       = (VOID *) (MicrocodeEntryPoint + 1);\r
      LatestRevision      = MicrocodeEntryPoint->UpdateRevision;\r
      goto Done;\r
    }\r
  }\r
\r
  LatestRevision = 0;\r
  MicrocodeData  = NULL;\r
  MicrocodeEnd = (UINTN) (CpuMpData->MicrocodePatchAddress + CpuMpData->MicrocodePatchRegionSize);\r
  MicrocodeEntryPoint = (CPU_MICROCODE_HEADER *) (UINTN) CpuMpData->MicrocodePatchAddress;\r
\r
  do {\r
    //\r
    // Check if the microcode is for the Cpu and the version is newer\r
    // and the update can be processed on the platform\r
    //\r
    CorrectMicrocode = FALSE;\r
\r
    if (MicrocodeEntryPoint->DataSize == 0) {\r
      TotalSize = sizeof (CPU_MICROCODE_HEADER) + 2000;\r
    } else {\r
      TotalSize = sizeof (CPU_MICROCODE_HEADER) + MicrocodeEntryPoint->DataSize;\r
    }\r
\r
    ///\r
    /// 0x0       MicrocodeBegin  MicrocodeEntry  MicrocodeEnd      0xffffffff\r
    /// |--------------|---------------|---------------|---------------|\r
    ///                                 valid TotalSize\r
    /// TotalSize is only valid between 0 and (MicrocodeEnd - MicrocodeEntry).\r
    /// And it should be aligned with 4 bytes.\r
    /// If the TotalSize is invalid, skip 1KB to check next entry.\r
    ///\r
    if ( (UINTN)MicrocodeEntryPoint > (MAX_ADDRESS - TotalSize) ||\r
         ((UINTN)MicrocodeEntryPoint + TotalSize) > MicrocodeEnd ||\r
         (TotalSize & 0x3) != 0\r
       ) {\r
      MicrocodeEntryPoint = (CPU_MICROCODE_HEADER *) (((UINTN) MicrocodeEntryPoint) + SIZE_1KB);\r
      continue;\r
    }\r
\r
    //\r
    // Save an in-complete CheckSum32 from CheckSum Part1 for common parts.\r
    //\r
    InCompleteCheckSum32 = CalculateSum32 (\r
                             (UINT32 *) MicrocodeEntryPoint,\r
                             TotalSize\r
                             );\r
    InCompleteCheckSum32 -= MicrocodeEntryPoint->ProcessorSignature.Uint32;\r
    InCompleteCheckSum32 -= MicrocodeEntryPoint->ProcessorFlags;\r
    InCompleteCheckSum32 -= MicrocodeEntryPoint->Checksum;\r
\r
    if (MicrocodeEntryPoint->HeaderVersion == 0x1) {\r
      //\r
      // It is the microcode header. It is not the padding data between microcode patches\r
      // because the padding data should not include 0x00000001 and it should be the repeated\r
      // byte format (like 0xXYXYXYXY....).\r
      //\r
      if (MicrocodeEntryPoint->ProcessorSignature.Uint32 == Eax.Uint32 &&\r
          MicrocodeEntryPoint->UpdateRevision > LatestRevision &&\r
          (MicrocodeEntryPoint->ProcessorFlags & (1 << PlatformId))\r
          ) {\r
        //\r
        // Calculate CheckSum Part1.\r
        //\r
        CheckSum32 = InCompleteCheckSum32;\r
        CheckSum32 += MicrocodeEntryPoint->ProcessorSignature.Uint32;\r
        CheckSum32 += MicrocodeEntryPoint->ProcessorFlags;\r
        CheckSum32 += MicrocodeEntryPoint->Checksum;\r
        if (CheckSum32 == 0) {\r
          CorrectMicrocode = TRUE;\r
        }\r
      } else if ((MicrocodeEntryPoint->DataSize != 0) &&\r
                 (MicrocodeEntryPoint->UpdateRevision > LatestRevision)) {\r
        ExtendedTableLength = MicrocodeEntryPoint->TotalSize - (MicrocodeEntryPoint->DataSize +\r
                                sizeof (CPU_MICROCODE_HEADER));\r
        if (ExtendedTableLength != 0) {\r
          //\r
          // Extended Table exist, check if the CPU in support list\r
          //\r
          ExtendedTableHeader = (CPU_MICROCODE_EXTENDED_TABLE_HEADER *) ((UINT8 *) (MicrocodeEntryPoint)\r
                                  + MicrocodeEntryPoint->DataSize + sizeof (CPU_MICROCODE_HEADER));\r
          //\r
          // Calculate Extended Checksum\r
          //\r
          if ((ExtendedTableLength % 4) == 0) {\r
            //\r
            // Calculate CheckSum Part2.\r
            //\r
            CheckSum32 = CalculateSum32 ((UINT32 *) ExtendedTableHeader, ExtendedTableLength);\r
            if (CheckSum32 == 0) {\r
              //\r
              // Checksum correct\r
              //\r
              ExtendedTableCount = ExtendedTableHeader->ExtendedSignatureCount;\r
              ExtendedTable      = (CPU_MICROCODE_EXTENDED_TABLE *) (ExtendedTableHeader + 1);\r
              for (Index = 0; Index < ExtendedTableCount; Index ++) {\r
                //\r
                // Calculate CheckSum Part3.\r
                //\r
                CheckSum32 = InCompleteCheckSum32;\r
                CheckSum32 += ExtendedTable->ProcessorSignature.Uint32;\r
                CheckSum32 += ExtendedTable->ProcessorFlag;\r
                CheckSum32 += ExtendedTable->Checksum;\r
                if (CheckSum32 == 0) {\r
                  //\r
                  // Verify Header\r
                  //\r
                  if ((ExtendedTable->ProcessorSignature.Uint32 == Eax.Uint32) &&\r
                      (ExtendedTable->ProcessorFlag & (1 << PlatformId)) ) {\r
                    //\r
                    // Find one\r
                    //\r
                    CorrectMicrocode = TRUE;\r
                    break;\r
                  }\r
                }\r
                ExtendedTable ++;\r
              }\r
            }\r
          }\r
        }\r
      }\r
    } else {\r
      //\r
      // It is the padding data between the microcode patches for microcode patches alignment.\r
      // Because the microcode patch is the multiple of 1-KByte, the padding data should not\r
      // exist if the microcode patch alignment value is not larger than 1-KByte. So, the microcode\r
      // alignment value should be larger than 1-KByte. We could skip SIZE_1KB padding data to\r
      // find the next possible microcode patch header.\r
      //\r
      MicrocodeEntryPoint = (CPU_MICROCODE_HEADER *) (((UINTN) MicrocodeEntryPoint) + SIZE_1KB);\r
      continue;\r
    }\r
    //\r
    // Get the next patch.\r
    //\r
    if (MicrocodeEntryPoint->DataSize == 0) {\r
      TotalSize = 2048;\r
    } else {\r
      TotalSize = MicrocodeEntryPoint->TotalSize;\r
    }\r
\r
    if (CorrectMicrocode) {\r
      LatestRevision = MicrocodeEntryPoint->UpdateRevision;\r
      MicrocodeData = (VOID *) ((UINTN) MicrocodeEntryPoint + sizeof (CPU_MICROCODE_HEADER));\r
    }\r
\r
    MicrocodeEntryPoint = (CPU_MICROCODE_HEADER *) (((UINTN) MicrocodeEntryPoint) + TotalSize);\r
  } while (((UINTN) MicrocodeEntryPoint < MicrocodeEnd));\r
\r
Done:\r
  if (LatestRevision != 0) {\r
    //\r
    // Save the detected microcode patch entry address (including the\r
    // microcode patch header) for each processor.\r
    // It will be used when building the microcode patch cache HOB.\r
    //\r
    CpuMpData->CpuData[ProcessorNumber].MicrocodeEntryAddr =\r
      (UINTN) MicrocodeData -  sizeof (CPU_MICROCODE_HEADER);\r
  }\r
\r
  if (LatestRevision > CurrentRevision) {\r
    //\r
    // BIOS only authenticate updates that contain a numerically larger revision\r
    // than the currently loaded revision, where Current Signature < New Update\r
    // Revision. A processor with no loaded update is considered to have a\r
    // revision equal to zero.\r
    //\r
    ASSERT (MicrocodeData != NULL);\r
    AsmWriteMsr64 (\r
        MSR_IA32_BIOS_UPDT_TRIG,\r
        (UINT64) (UINTN) MicrocodeData\r
        );\r
    //\r
    // Get and check new microcode signature\r
    //\r
    CurrentRevision = GetCurrentMicrocodeSignature ();\r
    if (CurrentRevision != LatestRevision) {\r
      AcquireSpinLock(&CpuMpData->MpLock);\r
      DEBUG ((EFI_D_ERROR, "Updated microcode signature [0x%08x] does not match \\r
                loaded microcode signature [0x%08x]\n", CurrentRevision, LatestRevision));\r
      ReleaseSpinLock(&CpuMpData->MpLock);\r
    }\r
  }\r
}\r
\r
/**\r
  Determine if a microcode patch will be loaded into memory.\r
\r
  @param[in]  CpuMpData             The pointer to CPU MP Data structure.\r
  @param[in]  ProcessorSignature    The processor signature field value\r
                                    supported by a microcode patch.\r
  @param[in]  ProcessorFlags        The prcessor flags field value supported by\r
                                    a microcode patch.\r
\r
  @retval TRUE     The specified microcode patch will be loaded.\r
  @retval FALSE    The specified microcode patch will not be loaded.\r
**/\r
BOOLEAN\r
IsMicrocodePatchNeedLoad (\r
  IN CPU_MP_DATA                 *CpuMpData,\r
  IN UINT32                      ProcessorSignature,\r
  IN UINT32                      ProcessorFlags\r
  )\r
{\r
  UINTN          Index;\r
  CPU_AP_DATA    *CpuData;\r
\r
  for (Index = 0; Index < CpuMpData->CpuCount; Index++) {\r
    CpuData = &CpuMpData->CpuData[Index];\r
    if ((ProcessorSignature == CpuData->ProcessorSignature) &&\r
        (ProcessorFlags & (1 << CpuData->PlatformId)) != 0) {\r
      return TRUE;\r
    }\r
  }\r
\r
  return FALSE;\r
}\r
\r
/**\r
  Actual worker function that loads the required microcode patches into memory.\r
\r
  @param[in, out]  CpuMpData        The pointer to CPU MP Data structure.\r
  @param[in]       Patches          The pointer to an array of information on\r
                                    the microcode patches that will be loaded\r
                                    into memory.\r
  @param[in]       PatchCount       The number of microcode patches that will\r
                                    be loaded into memory.\r
  @param[in]       TotalLoadSize    The total size of all the microcode patches\r
                                    to be loaded.\r
**/\r
VOID\r
LoadMicrocodePatchWorker (\r
  IN OUT CPU_MP_DATA             *CpuMpData,\r
  IN     MICROCODE_PATCH_INFO    *Patches,\r
  IN     UINTN                   PatchCount,\r
  IN     UINTN                   TotalLoadSize\r
  )\r
{\r
  UINTN    Index;\r
  VOID     *MicrocodePatchInRam;\r
  UINT8    *Walker;\r
\r
  ASSERT ((Patches != NULL) && (PatchCount != 0));\r
\r
  MicrocodePatchInRam = AllocatePages (EFI_SIZE_TO_PAGES (TotalLoadSize));\r
  if (MicrocodePatchInRam == NULL) {\r
    return;\r
  }\r
\r
  //\r
  // Load all the required microcode patches into memory\r
  //\r
  for (Walker = MicrocodePatchInRam, Index = 0; Index < PatchCount; Index++) {\r
    CopyMem (\r
      Walker,\r
      (VOID *) Patches[Index].Address,\r
      Patches[Index].Size\r
      );\r
\r
    Walker += Patches[Index].Size;\r
  }\r
\r
  //\r
  // Update the microcode patch related fields in CpuMpData\r
  //\r
  CpuMpData->MicrocodePatchAddress    = (UINTN) MicrocodePatchInRam;\r
  CpuMpData->MicrocodePatchRegionSize = TotalLoadSize;\r
\r
  DEBUG ((\r
    DEBUG_INFO,\r
    "%a: Required microcode patches have been loaded at 0x%lx, with size 0x%lx.\n",\r
    __FUNCTION__, CpuMpData->MicrocodePatchAddress, CpuMpData->MicrocodePatchRegionSize\r
    ));\r
\r
  return;\r
}\r
\r
/**\r
  Load the required microcode patches data into memory.\r
\r
  @param[in, out]  CpuMpData    The pointer to CPU MP Data structure.\r
**/\r
VOID\r
LoadMicrocodePatch (\r
  IN OUT CPU_MP_DATA             *CpuMpData\r
  )\r
{\r
  CPU_MICROCODE_HEADER                   *MicrocodeEntryPoint;\r
  UINTN                                  MicrocodeEnd;\r
  UINTN                                  DataSize;\r
  UINTN                                  TotalSize;\r
  CPU_MICROCODE_EXTENDED_TABLE_HEADER    *ExtendedTableHeader;\r
  UINT32                                 ExtendedTableCount;\r
  CPU_MICROCODE_EXTENDED_TABLE           *ExtendedTable;\r
  MICROCODE_PATCH_INFO                   *PatchInfoBuffer;\r
  UINTN                                  MaxPatchNumber;\r
  UINTN                                  PatchCount;\r
  UINTN                                  TotalLoadSize;\r
  UINTN                                  Index;\r
  BOOLEAN                                NeedLoad;\r
\r
  //\r
  // Initialize the microcode patch related fields in CpuMpData as the values\r
  // specified by the PCD pair. If the microcode patches are loaded into memory,\r
  // these fields will be updated.\r
  //\r
  CpuMpData->MicrocodePatchAddress    = PcdGet64 (PcdCpuMicrocodePatchAddress);\r
  CpuMpData->MicrocodePatchRegionSize = PcdGet64 (PcdCpuMicrocodePatchRegionSize);\r
\r
  MicrocodeEntryPoint    = (CPU_MICROCODE_HEADER *) (UINTN) CpuMpData->MicrocodePatchAddress;\r
  MicrocodeEnd           = (UINTN) MicrocodeEntryPoint +\r
                           (UINTN) CpuMpData->MicrocodePatchRegionSize;\r
  if ((MicrocodeEntryPoint == NULL) || ((UINTN) MicrocodeEntryPoint == MicrocodeEnd)) {\r
    //\r
    // There is no microcode patches\r
    //\r
    return;\r
  }\r
\r
  PatchCount      = 0;\r
  MaxPatchNumber  = DEFAULT_MAX_MICROCODE_PATCH_NUM;\r
  TotalLoadSize   = 0;\r
  PatchInfoBuffer = AllocatePool (MaxPatchNumber * sizeof (MICROCODE_PATCH_INFO));\r
  if (PatchInfoBuffer == NULL) {\r
    return;\r
  }\r
\r
  //\r
  // Process the header of each microcode patch within the region.\r
  // The purpose is to decide which microcode patch(es) will be loaded into memory.\r
  //\r
  do {\r
    if (MicrocodeEntryPoint->HeaderVersion != 0x1) {\r
      //\r
      // Padding data between the microcode patches, skip 1KB to check next entry.\r
      //\r
      MicrocodeEntryPoint = (CPU_MICROCODE_HEADER *) (((UINTN) MicrocodeEntryPoint) + SIZE_1KB);\r
      continue;\r
    }\r
\r
    DataSize  = MicrocodeEntryPoint->DataSize;\r
    TotalSize = (DataSize == 0) ? 2048 : MicrocodeEntryPoint->TotalSize;\r
    if ( (UINTN)MicrocodeEntryPoint > (MAX_ADDRESS - TotalSize) ||\r
         ((UINTN)MicrocodeEntryPoint + TotalSize) > MicrocodeEnd ||\r
         (DataSize & 0x3) != 0 ||\r
         (TotalSize & (SIZE_1KB - 1)) != 0 ||\r
         TotalSize < DataSize\r
       ) {\r
      //\r
      // Not a valid microcode header, skip 1KB to check next entry.\r
      //\r
      MicrocodeEntryPoint = (CPU_MICROCODE_HEADER *) (((UINTN) MicrocodeEntryPoint) + SIZE_1KB);\r
      continue;\r
    }\r
\r
    //\r
    // Check the 'ProcessorSignature' and 'ProcessorFlags' of the microcode\r
    // patch header with the CPUID and PlatformID of the processors within\r
    // system to decide if it will be copied into memory\r
    //\r
    NeedLoad = IsMicrocodePatchNeedLoad (\r
                 CpuMpData,\r
                 MicrocodeEntryPoint->ProcessorSignature.Uint32,\r
                 MicrocodeEntryPoint->ProcessorFlags\r
                 );\r
\r
    //\r
    // If the Extended Signature Table exists, check if the processor is in the\r
    // support list\r
    //\r
    if ((!NeedLoad) && (DataSize != 0) &&\r
        (TotalSize - DataSize > sizeof (CPU_MICROCODE_HEADER) +\r
                                sizeof (CPU_MICROCODE_EXTENDED_TABLE_HEADER))) {\r
      ExtendedTableHeader = (CPU_MICROCODE_EXTENDED_TABLE_HEADER *) ((UINT8 *) (MicrocodeEntryPoint)\r
                              + DataSize + sizeof (CPU_MICROCODE_HEADER));\r
      ExtendedTableCount  = ExtendedTableHeader->ExtendedSignatureCount;\r
      ExtendedTable       = (CPU_MICROCODE_EXTENDED_TABLE *) (ExtendedTableHeader + 1);\r
\r
      for (Index = 0; Index < ExtendedTableCount; Index ++) {\r
        //\r
        // Avoid access content beyond MicrocodeEnd\r
        //\r
        if ((UINTN) ExtendedTable > MicrocodeEnd - sizeof (CPU_MICROCODE_EXTENDED_TABLE)) {\r
          break;\r
        }\r
\r
        //\r
        // Check the 'ProcessorSignature' and 'ProcessorFlag' of the Extended\r
        // Signature Table entry with the CPUID and PlatformID of the processors\r
        // within system to decide if it will be copied into memory\r
        //\r
        NeedLoad = IsMicrocodePatchNeedLoad (\r
                     CpuMpData,\r
                     ExtendedTable->ProcessorSignature.Uint32,\r
                     ExtendedTable->ProcessorFlag\r
                     );\r
        if (NeedLoad) {\r
          break;\r
        }\r
        ExtendedTable ++;\r
      }\r
    }\r
\r
    if (NeedLoad) {\r
      PatchCount++;\r
      if (PatchCount > MaxPatchNumber) {\r
        //\r
        // Current 'PatchInfoBuffer' cannot hold the information, double the size\r
        // and allocate a new buffer.\r
        //\r
        if (MaxPatchNumber > MAX_UINTN / 2 / sizeof (MICROCODE_PATCH_INFO)) {\r
          //\r
          // Overflow check for MaxPatchNumber\r
          //\r
          goto OnExit;\r
        }\r
\r
        PatchInfoBuffer = ReallocatePool (\r
                            MaxPatchNumber * sizeof (MICROCODE_PATCH_INFO),\r
                            2 * MaxPatchNumber * sizeof (MICROCODE_PATCH_INFO),\r
                            PatchInfoBuffer\r
                            );\r
        if (PatchInfoBuffer == NULL) {\r
          goto OnExit;\r
        }\r
        MaxPatchNumber = MaxPatchNumber * 2;\r
      }\r
\r
      //\r
      // Store the information of this microcode patch\r
      //\r
      PatchInfoBuffer[PatchCount - 1].Address = (UINTN) MicrocodeEntryPoint;\r
      PatchInfoBuffer[PatchCount - 1].Size    = TotalSize;\r
      TotalLoadSize += TotalSize;\r
    }\r
\r
    //\r
    // Process the next microcode patch\r
    //\r
    MicrocodeEntryPoint = (CPU_MICROCODE_HEADER *) (((UINTN) MicrocodeEntryPoint) + TotalSize);\r
  } while (((UINTN) MicrocodeEntryPoint < MicrocodeEnd));\r
\r
  if (PatchCount != 0) {\r
    DEBUG ((\r
      DEBUG_INFO,\r
      "%a: 0x%x microcode patches will be loaded into memory, with size 0x%x.\n",\r
      __FUNCTION__, PatchCount, TotalLoadSize\r
      ));\r
\r
    LoadMicrocodePatchWorker (CpuMpData, PatchInfoBuffer, PatchCount, TotalLoadSize);\r
  }\r
\r
OnExit:\r
  if (PatchInfoBuffer != NULL) {\r
    FreePool (PatchInfoBuffer);\r
  }\r
  return;\r
}\r