1 /** @file
2 Execute Disable 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 Execute Disable 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 Execute Disable feature is supported.
23 @retval FALSE Execute Disable feature is not supported.
24
25 @note This service could be called by BSP/APs.
26 **/
27 BOOLEAN
28 EFIAPI
ExecuteDisableSupport(IN UINTN ProcessorNumber,IN REGISTER_CPU_FEATURE_INFORMATION * CpuInfo,IN VOID * ConfigData OPTIONAL)29 ExecuteDisableSupport (
30 IN UINTN ProcessorNumber,
31 IN REGISTER_CPU_FEATURE_INFORMATION *CpuInfo,
32 IN VOID *ConfigData OPTIONAL
33 )
34 {
35 UINT32 Eax;
36 CPUID_EXTENDED_CPU_SIG_EDX Edx;
37
38 AsmCpuid (CPUID_EXTENDED_FUNCTION, &Eax, NULL, NULL, NULL);
39 if (Eax <= CPUID_EXTENDED_FUNCTION) {
40 //
41 // Extended CPUID functions are not supported on this processor.
42 //
43 return FALSE;
44 }
45
46 AsmCpuid (CPUID_EXTENDED_CPU_SIG, NULL, NULL, NULL, &Edx.Uint32);
47 return (Edx.Bits.NX != 0);
48 }
49
50 /**
51 Initializes Execute Disable feature to specific state.
52
53 @param[in] ProcessorNumber The index of the CPU executing this function.
54 @param[in] CpuInfo A pointer to the REGISTER_CPU_FEATURE_INFORMATION
55 structure for the CPU executing this function.
56 @param[in] ConfigData A pointer to the configuration buffer returned
57 by CPU_FEATURE_GET_CONFIG_DATA. NULL if
58 CPU_FEATURE_GET_CONFIG_DATA was not provided in
59 RegisterCpuFeature().
60 @param[in] State If TRUE, then the Execute Disable feature must be enabled.
61 If FALSE, then the Execute Disable feature must be disabled.
62
63 @retval RETURN_SUCCESS Execute Disable feature is initialized.
64
65 @note This service could be called by BSP only.
66 **/
67 RETURN_STATUS
68 EFIAPI
ExecuteDisableInitialize(IN UINTN ProcessorNumber,IN REGISTER_CPU_FEATURE_INFORMATION * CpuInfo,IN VOID * ConfigData,OPTIONAL IN BOOLEAN State)69 ExecuteDisableInitialize (
70 IN UINTN ProcessorNumber,
71 IN REGISTER_CPU_FEATURE_INFORMATION *CpuInfo,
72 IN VOID *ConfigData, OPTIONAL
73 IN BOOLEAN State
74 )
75 {
76 //
77 // The scope of the MSR_IA32_EFER is core for below processor type, only program
78 // MSR_IA32_EFER for thread 0 in each core.
79 //
80 if (IS_SILVERMONT_PROCESSOR (CpuInfo->DisplayFamily, CpuInfo->DisplayModel)) {
81 if (CpuInfo->ProcessorInfo.Location.Thread != 0) {
82 return RETURN_SUCCESS;
83 }
84 }
85
86 CPU_REGISTER_TABLE_WRITE_FIELD (
87 ProcessorNumber,
88 Msr,
89 MSR_IA32_EFER,
90 MSR_IA32_EFER_REGISTER,
91 Bits.NXE,
92 (State) ? 1 : 0
93 );
94 return RETURN_SUCCESS;
95 }
96