UefiCpuPkg: Add NULL CPU Common Features Library instance
[mirror_edk2.git] / UefiCpuPkg / Library / CpuCommonFeaturesLib / MonitorMwait.c
1 /** @file
2 MonitorMwait 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 Detects if MONITOR/MWAIT feature supported on current processor.
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
28 @retval TRUE MONITOR/MWAIT feature is supported.
29 @retval FALSE MONITOR/MWAIT feature is not supported.
30
31 @note This service could be called by BSP/APs.
32 **/
33 BOOLEAN
34 EFIAPI
35 MonitorMwaitSupport (
36 IN UINTN ProcessorNumber,
37 IN REGISTER_CPU_FEATURE_INFORMATION *CpuInfo,
38 IN VOID *ConfigData OPTIONAL
39 )
40 {
41 return (CpuInfo->CpuIdVersionInfoEcx.Bits.MONITOR == 1);
42 }
43
44 /**
45 Initializes MONITOR/MWAIT feature to specific state.
46
47 @param[in] ProcessorNumber The index of the CPU executing this function.
48 @param[in] CpuInfo A pointer to the REGISTER_CPU_FEATURE_INFORMATION
49 structure for the CPU executing this function.
50 @param[in] ConfigData A pointer to the configuration buffer returned
51 by CPU_FEATURE_GET_CONFIG_DATA. NULL if
52 CPU_FEATURE_GET_CONFIG_DATA was not provided in
53 RegisterCpuFeature().
54 @param[in] State If TRUE, then the MONITOR/MWAIT feature must be enabled.
55 If FALSE, then the MONITOR/MWAIT feature must be disabled.
56
57 @retval RETURN_SUCCESS MONITOR/MWAIT feature is initialized.
58
59 @note This service could be called by BSP only.
60 **/
61 RETURN_STATUS
62 EFIAPI
63 MonitorMwaitInitialize (
64 IN UINTN ProcessorNumber,
65 IN REGISTER_CPU_FEATURE_INFORMATION *CpuInfo,
66 IN VOID *ConfigData, OPTIONAL
67 IN BOOLEAN State
68 )
69 {
70 CPU_REGISTER_TABLE_WRITE_FIELD (
71 ProcessorNumber,
72 Msr,
73 MSR_IA32_MISC_ENABLE,
74 MSR_IA32_MISC_ENABLE_REGISTER,
75 Bits.MONITOR,
76 (State) ? 1 : 0
77 );
78 return RETURN_SUCCESS;
79 }