UefiCpuPkg/Library/CpuCommonFeaturesLib/FastStrings.c

   1 /** @file
   2   Fast-Strings feature.
   3
   4   Copyright (c) 2017, Intel Corporation. All rights reserved.<BR>
   5   SPDX-License-Identifier: BSD-2-Clause-Patent
   6
   7 **/
   8
   9 #include "CpuCommonFeatures.h"
  10
  11 /**
  12   Initializes Fast-Strings feature to specific state.
  13
  14   @param[in]  ProcessorNumber  The index of the CPU executing this function.
  15   @param[in]  CpuInfo          A pointer to the REGISTER_CPU_FEATURE_INFORMATION
  16                                structure for the CPU executing this function.
  17   @param[in]  ConfigData       A pointer to the configuration buffer returned
  18                                by CPU_FEATURE_GET_CONFIG_DATA.  NULL if
  19                                CPU_FEATURE_GET_CONFIG_DATA was not provided in
  20                                RegisterCpuFeature().
  21   @param[in]  State            If TRUE, then the Fast-Strings feature must be enabled.
  22                                If FALSE, then the Fast-Strings feature must be disabled.
  23
  24   @retval RETURN_SUCCESS       Fast-Strings feature is initialized.
  25
  26   @note This service could be called by BSP only.
  27 **/
  28 RETURN_STATUS
  29 EFIAPI
  30 FastStringsInitialize (
  31   IN UINTN                             ProcessorNumber,
  32   IN REGISTER_CPU_FEATURE_INFORMATION  *CpuInfo,
  33   IN VOID                              *ConfigData   OPTIONAL,
  34   IN BOOLEAN                           State
  35   )
  36 {
  37   //
  38   // The scope of FastStrings bit in the MSR_IA32_MISC_ENABLE is core for below processor type, only program
  39   // MSR_IA32_MISC_ENABLE for thread 0 in each core.
  40   //
  41   if (IS_SILVERMONT_PROCESSOR (CpuInfo->DisplayFamily, CpuInfo->DisplayModel) ||
  42       IS_GOLDMONT_PROCESSOR (CpuInfo->DisplayFamily, CpuInfo->DisplayModel) ||
  43       IS_PENTIUM_4_PROCESSOR (CpuInfo->DisplayFamily, CpuInfo->DisplayModel))
  44   {
  45     if (CpuInfo->ProcessorInfo.Location.Thread != 0) {
  46       return RETURN_SUCCESS;
  47     }
  48   }
  49
  50   CPU_REGISTER_TABLE_WRITE_FIELD (
  51     ProcessorNumber,
  52     Msr,
  53     MSR_IA32_MISC_ENABLE,
  54     MSR_IA32_MISC_ENABLE_REGISTER,
  55     Bits.FastStrings,
  56     (State) ? 1 : 0
  57     );
  58   return RETURN_SUCCESS;
  59 }