UefiCpuPkg/Library/CpuCommonFeaturesLib/FastStrings.c

   1 /** @file
   2   Fast-Strings feature.
   3
   4   Copyright (c) 2017, Intel Corporation. All rights reserved.<BR>
   5   This program and the accompanying materials
   6   are licensed and made available under the terms and conditions of the BSD License
   7   which accompanies this distribution.  The full text of the license may be found at
   8   http://opensource.org/licenses/bsd-license.php
   9
  10   THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
  11   WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
  12
  13 **/
  14
  15 #include "CpuCommonFeatures.h"
  16
  17 /**
  18   Initializes Fast-Strings feature to specific state.
  19
  20   @param[in]  ProcessorNumber  The index of the CPU executing this function.
  21   @param[in]  CpuInfo          A pointer to the REGISTER_CPU_FEATURE_INFORMATION
  22                                structure for the CPU executing this function.
  23   @param[in]  ConfigData       A pointer to the configuration buffer returned
  24                                by CPU_FEATURE_GET_CONFIG_DATA.  NULL if
  25                                CPU_FEATURE_GET_CONFIG_DATA was not provided in
  26                                RegisterCpuFeature().
  27   @param[in]  State            If TRUE, then the Fast-Strings feature must be enabled.
  28                                If FALSE, then the Fast-Strings feature must be disabled.
  29
  30   @retval RETURN_SUCCESS       Fast-Strings feature is initialized.
  31
  32   @note This service could be called by BSP only.
  33 **/
  34 RETURN_STATUS
  35 EFIAPI
  36 FastStringsInitialize (
  37   IN UINTN                             ProcessorNumber,
  38   IN REGISTER_CPU_FEATURE_INFORMATION  *CpuInfo,
  39   IN VOID                              *ConfigData,  OPTIONAL
  40   IN BOOLEAN                           State
  41   )
  42 {
  43   //
  44   // The scope of FastStrings bit in the MSR_IA32_MISC_ENABLE is core for below processor type, only program
  45   // MSR_IA32_MISC_ENABLE for thread 0 in each core.
  46   //
  47   if (IS_SILVERMONT_PROCESSOR (CpuInfo->DisplayFamily, CpuInfo->DisplayModel) ||
  48       IS_GOLDMONT_PROCESSOR (CpuInfo->DisplayFamily, CpuInfo->DisplayModel) ||
  49       IS_PENTIUM_4_PROCESSOR (CpuInfo->DisplayFamily, CpuInfo->DisplayModel)) {
  50     if (CpuInfo->ProcessorInfo.Location.Thread != 0) {
  51       return RETURN_SUCCESS;
  52     }
  53   }
  54
  55   CPU_REGISTER_TABLE_WRITE_FIELD (
  56     ProcessorNumber,
  57     Msr,
  58     MSR_IA32_MISC_ENABLE,
  59     MSR_IA32_MISC_ENABLE_REGISTER,
  60     Bits.FastStrings,
  61     (State) ? 1 : 0
  62     );
  63   return RETURN_SUCCESS;
  64 }