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/** @file
LimitCpuidMaxval 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"
/**
Detects if LimitCpuidMaxval feature supported on current processor.
@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 LimitCpuidMaxval feature is supported.
@retval FALSE LimitCpuidMaxval feature is not supported.
@note This service could be called by BSP/APs.
**/
BOOLEAN
EFIAPI
LimitCpuidMaxvalSupport (
IN UINTN ProcessorNumber,
IN REGISTER_CPU_FEATURE_INFORMATION *CpuInfo,
IN VOID *ConfigData OPTIONAL
)
{
UINT32 Eax;
AsmCpuid (CPUID_SIGNATURE, &Eax, NULL, NULL, NULL);
return (Eax > 3);
}
/**
Initializes LimitCpuidMaxval 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 LimitCpuidMaxval feature must be enabled.
If FALSE, then the LimitCpuidMaxval feature must be disabled.
@retval RETURN_SUCCESS LimitCpuidMaxval feature is initialized.
@note This service could be called by BSP only.
**/
RETURN_STATUS
EFIAPI
LimitCpuidMaxvalInitialize (
IN UINTN ProcessorNumber,
IN REGISTER_CPU_FEATURE_INFORMATION *CpuInfo,
IN VOID *ConfigData, OPTIONAL
IN BOOLEAN State
)
{
CPU_REGISTER_TABLE_WRITE_FIELD (
ProcessorNumber,
Msr,
MSR_IA32_MISC_ENABLE,
MSR_IA32_MISC_ENABLE_REGISTER,
Bits.LimitCpuidMaxval,
(State) ? 1 : 0
);
return RETURN_SUCCESS;
}
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