UefiCpuPkg/Library/CpuCommonFeaturesLib/Eist.c

   1 /** @file
   2   Enhanced Intel SpeedStep 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   Detects if Enhanced Intel SpeedStep feature supported on current processor.
  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
  22   @retval TRUE     Enhanced Intel SpeedStep feature is supported.
  23   @retval FALSE    Enhanced Intel SpeedStep feature is not supported.
  24
  25   @note This service could be called by BSP/APs.
  26 **/
  27 BOOLEAN
  28 EFIAPI
  29 EistSupport (
  30   IN UINTN                             ProcessorNumber,
  31   IN REGISTER_CPU_FEATURE_INFORMATION  *CpuInfo,
  32   IN VOID                              *ConfigData  OPTIONAL
  33   )
  34 {
  35   return (CpuInfo->CpuIdVersionInfoEcx.Bits.EIST == 1);
  36 }
  37
  38 /**
  39   Initializes Enhanced Intel SpeedStep feature to specific state.
  40
  41   @param[in]  ProcessorNumber  The index of the CPU executing this function.
  42   @param[in]  CpuInfo          A pointer to the REGISTER_CPU_FEATURE_INFORMATION
  43                                structure for the CPU executing this function.
  44   @param[in]  ConfigData       A pointer to the configuration buffer returned
  45                                by CPU_FEATURE_GET_CONFIG_DATA.  NULL if
  46                                CPU_FEATURE_GET_CONFIG_DATA was not provided in
  47                                RegisterCpuFeature().
  48   @param[in]  State            If TRUE, then the Enhanced Intel SpeedStep feature
  49                                must be enabled.
  50                                If FALSE, then the Enhanced Intel SpeedStep feature
  51                                must be disabled.
  52
  53   @retval RETURN_SUCCESS       Enhanced Intel SpeedStep feature is initialized.
  54
  55   @note This service could be called by BSP only.
  56 **/
  57 RETURN_STATUS
  58 EFIAPI
  59 EistInitialize (
  60   IN UINTN                             ProcessorNumber,
  61   IN REGISTER_CPU_FEATURE_INFORMATION  *CpuInfo,
  62   IN VOID                              *ConfigData   OPTIONAL,
  63   IN BOOLEAN                           State
  64   )
  65 {
  66   //
  67   // The scope of the MSR_IA32_MISC_ENABLE is core for below processor type, only program
  68   // MSR_IA32_MISC_ENABLE for thread 0 in each core.
  69   //
  70   if (IS_ATOM_PROCESSOR (CpuInfo->DisplayFamily, CpuInfo->DisplayModel) ||
  71       IS_CORE_PROCESSOR (CpuInfo->DisplayFamily, CpuInfo->DisplayModel) ||
  72       IS_CORE2_PROCESSOR (CpuInfo->DisplayFamily, CpuInfo->DisplayModel)) {
  73     if (CpuInfo->ProcessorInfo.Location.Thread != 0) {
  74       return RETURN_SUCCESS;
  75     }
  76   }
  77
  78   CPU_REGISTER_TABLE_WRITE_FIELD (
  79     ProcessorNumber,
  80     Msr,
  81     MSR_IA32_MISC_ENABLE,
  82     MSR_IA32_MISC_ENABLE_REGISTER,
  83     Bits.EIST,
  84     (State) ? 1 : 0
  85     );
  86   return RETURN_SUCCESS;
  87 }