UefiCpuPkg/CpuDxe: introduce two PCD value

[mirror_edk2.git] / UefiCpuPkg / CpuDxe / CpuMp.c

/** @file\r
  CPU DXE Module.\r
\r
  Copyright (c) 2008 - 2014, 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
  which accompanies this distribution.  The full text of the license may be found at\r
  http://opensource.org/licenses/bsd-license.php\r
\r
  THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,\r
  WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.\r
\r
**/\r
\r
#include "CpuDxe.h"\r
#include "CpuMp.h"\r
\r
UINTN gMaxLogicalProcessorNumber;\r
UINTN gApStackSize;\r
\r
VOID *mCommonStack = 0;\r
VOID *mTopOfApCommonStack = 0;\r
VOID *mApStackStart = 0;\r
\r
volatile UINTN mNumberOfProcessors;\r
\r
/**\r
  Application Processor C code entry point.\r
\r
**/\r
VOID\r
EFIAPI\r
ApEntryPointInC (\r
  VOID\r
  )\r
{\r
  mNumberOfProcessors++;\r
}\r
\r
\r
/**\r
  Initialize Multi-processor support.\r
\r
**/\r
VOID\r
InitializeMpSupport (\r
  VOID\r
  )\r
{\r
  gMaxLogicalProcessorNumber = (UINTN) PcdGet32 (PcdCpuMaxLogicalProcessorNumber);\r
  if (gMaxLogicalProcessorNumber < 1) {\r
    DEBUG ((DEBUG_ERROR, "Setting PcdCpuMaxLogicalProcessorNumber should be more than zero.\n"));\r
    return;\r
  }\r
\r
  if (gMaxLogicalProcessorNumber == 1) {\r
    return;\r
  }\r
\r
  gApStackSize = (UINTN) PcdGet32 (PcdCpuApStackSize);\r
  ASSERT ((gApStackSize & (SIZE_4KB - 1)) == 0);\r
\r
  mApStackStart = AllocatePages (EFI_SIZE_TO_PAGES (gMaxLogicalProcessorNumber * gApStackSize));\r
  ASSERT (mApStackStart != NULL);\r
\r
  //\r
  // the first buffer of stack size used for common stack, when the amount of AP\r
  // more than 1, we should never free the common stack which maybe used for AP reset.\r
  //\r
  mCommonStack = mApStackStart;\r
  mTopOfApCommonStack = (UINT8*) mApStackStart + gApStackSize;\r
  mApStackStart = mTopOfApCommonStack;\r
\r
  mNumberOfProcessors = 1;\r
\r
  if (mNumberOfProcessors == 1) {\r
    FreePages (mCommonStack, EFI_SIZE_TO_PAGES (gMaxLogicalProcessorNumber * gApStackSize));\r
    return;\r
  }\r
\r
  if (mNumberOfProcessors < gMaxLogicalProcessorNumber) {\r
    FreePages (mApStackStart, EFI_SIZE_TO_PAGES ((gMaxLogicalProcessorNumber - mNumberOfProcessors) *\r
                                                 gApStackSize));\r
  }\r
}\r