UefiCpuPkg: Add NULL CPU Common Features Library instance
[mirror_edk2.git] / UefiCpuPkg / Library / CpuCommonFeaturesLib / ExecuteDisable.c
1 /** @file
2 Execute Disable 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 Execute Disable 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 Execute Disable feature is supported.
29 @retval FALSE Execute Disable feature is not supported.
30
31 @note This service could be called by BSP/APs.
32 **/
33 BOOLEAN
34 EFIAPI
35 ExecuteDisableSupport (
36 IN UINTN ProcessorNumber,
37 IN REGISTER_CPU_FEATURE_INFORMATION *CpuInfo,
38 IN VOID *ConfigData OPTIONAL
39 )
40 {
41 UINT32 Eax;
42 CPUID_EXTENDED_CPU_SIG_EDX Edx;
43
44 AsmCpuid (CPUID_EXTENDED_FUNCTION, &Eax, NULL, NULL, NULL);
45 if (Eax <= CPUID_EXTENDED_FUNCTION) {
46 //
47 // Extended CPUID functions are not supported on this processor.
48 //
49 return FALSE;
50 }
51
52 AsmCpuid (CPUID_EXTENDED_CPU_SIG, NULL, NULL, NULL, &Edx.Uint32);
53 return (Edx.Bits.NX != 0);
54 }
55
56 /**
57 Initializes Execute Disable feature to specific state.
58
59 @param[in] ProcessorNumber The index of the CPU executing this function.
60 @param[in] CpuInfo A pointer to the REGISTER_CPU_FEATURE_INFORMATION
61 structure for the CPU executing this function.
62 @param[in] ConfigData A pointer to the configuration buffer returned
63 by CPU_FEATURE_GET_CONFIG_DATA. NULL if
64 CPU_FEATURE_GET_CONFIG_DATA was not provided in
65 RegisterCpuFeature().
66 @param[in] State If TRUE, then the Execute Disable feature must be enabled.
67 If FALSE, then the Execute Disable feature must be disabled.
68
69 @retval RETURN_SUCCESS Execute Disable feature is initialized.
70
71 @note This service could be called by BSP only.
72 **/
73 RETURN_STATUS
74 EFIAPI
75 ExecuteDisableInitialize (
76 IN UINTN ProcessorNumber,
77 IN REGISTER_CPU_FEATURE_INFORMATION *CpuInfo,
78 IN VOID *ConfigData, OPTIONAL
79 IN BOOLEAN State
80 )
81 {
82 CPU_REGISTER_TABLE_WRITE_FIELD (
83 ProcessorNumber,
84 Msr,
85 MSR_IA32_EFER,
86 MSR_IA32_EFER_REGISTER,
87 Bits.NXE,
88 (State) ? 1 : 0
89 );
90 return RETURN_SUCCESS;
91 }