audk/UefiCpuPkg/Library/CpuCommonFeaturesLib/X2Apic.c

/** @file
  X2Apic feature.

  Copyright (c) 2017, Intel Corporation. All rights reserved.<BR>
  This program and the accompanying materials
  are licensed and made available under the terms and conditions of the BSD License
  which accompanies this distribution.  The full text of the license may be found at
  http://opensource.org/licenses/bsd-license.php

  THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
  WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.

**/

#include "CpuCommonFeatures.h"

/**
  Prepares for the data used by CPU feature detection and initialization.

  @param[in]  NumberOfProcessors  The number of CPUs in the platform.

  @return  Pointer to a buffer of CPU related configuration data.

  @note This service could be called by BSP only.
**/
VOID *
EFIAPI
X2ApicGetConfigData (
  IN UINTN  NumberOfProcessors
  )
{
  BOOLEAN                            *ConfigData;

  ConfigData = AllocateZeroPool (sizeof (BOOLEAN) * NumberOfProcessors);
  ASSERT (ConfigData != NULL);
  return ConfigData;
}

/**
  Detects if X2Apci feature supported on current processor.

  Detect if X2Apci has been already enabled.

  @param[in]  ProcessorNumber  The index of the CPU executing this function.
  @param[in]  CpuInfo          A pointer to the REGISTER_CPU_FEATURE_INFORMATION
                               structure for the CPU executing this function.
  @param[in]  ConfigData       A pointer to the configuration buffer returned
                               by CPU_FEATURE_GET_CONFIG_DATA.  NULL if
                               CPU_FEATURE_GET_CONFIG_DATA was not provided in
                               RegisterCpuFeature().

  @retval TRUE     X2Apci feature is supported.
  @retval FALSE    X2Apci feature is not supported.

  @note This service could be called by BSP/APs.
**/
BOOLEAN
EFIAPI
X2ApicSupport (
  IN UINTN                             ProcessorNumber,
  IN REGISTER_CPU_FEATURE_INFORMATION  *CpuInfo,
  IN VOID                              *ConfigData  OPTIONAL
  )
{
  BOOLEAN                            *X2ApicEnabled;

  ASSERT (ConfigData != NULL);
  X2ApicEnabled = (BOOLEAN *) ConfigData;
  //
  // *ConfigData indicates if X2APIC enabled on current processor
  //
  X2ApicEnabled[ProcessorNumber] = (GetApicMode () == LOCAL_APIC_MODE_X2APIC) ? TRUE : FALSE;

  return (CpuInfo->CpuIdVersionInfoEcx.Bits.x2APIC == 1);
}

/**
  Initializes X2Apci feature to specific state.

  @param[in]  ProcessorNumber  The index of the CPU executing this function.
  @param[in]  CpuInfo          A pointer to the REGISTER_CPU_FEATURE_INFORMATION
                               structure for the CPU executing this function.
  @param[in]  ConfigData       A pointer to the configuration buffer returned
                               by CPU_FEATURE_GET_CONFIG_DATA.  NULL if
                               CPU_FEATURE_GET_CONFIG_DATA was not provided in
                               RegisterCpuFeature().
  @param[in]  State            If TRUE, then the X2Apci feature must be enabled.
                               If FALSE, then the X2Apci feature must be disabled.

  @retval RETURN_SUCCESS       X2Apci feature is initialized.

  @note This service could be called by BSP only.
**/
RETURN_STATUS
EFIAPI
X2ApicInitialize (
  IN UINTN                             ProcessorNumber,
  IN REGISTER_CPU_FEATURE_INFORMATION  *CpuInfo,
  IN VOID                              *ConfigData,  OPTIONAL
  IN BOOLEAN                           State
  )
{
  BOOLEAN                            *X2ApicEnabled;

  ASSERT (ConfigData != NULL);
  X2ApicEnabled = (BOOLEAN *) ConfigData;
  if (X2ApicEnabled[ProcessorNumber]) {
    PRE_SMM_CPU_REGISTER_TABLE_WRITE_FIELD (
      ProcessorNumber,
      Msr,
      MSR_IA32_APIC_BASE,
      MSR_IA32_APIC_BASE_REGISTER,
      Bits.EXTD,
      1
      );
  } else {
    //
    // Enable X2APIC mode only if X2APIC is not enabled,
    // Needn't to disabe X2APIC mode again if X2APIC is not enabled
    //
    if (State) {
      CPU_REGISTER_TABLE_WRITE_FIELD (
        ProcessorNumber,
        Msr,
        MSR_IA32_APIC_BASE,
        MSR_IA32_APIC_BASE_REGISTER,
        Bits.EXTD,
        1
        );
    }
  }
  return RETURN_SUCCESS;
}