1 /** @file 2 EFI SMM Access PPI definition. 3 4 This PPI is used to control the visibility of the SMRAM on the platform. 5 It abstracts the location and characteristics of SMRAM. The expectation is 6 that the north bridge or memory controller would publish this PPI. 7 8 The principal functionality found in the memory controller includes the following: 9 - Exposing the SMRAM to all non-SMM agents, or the "open" state 10 - Shrouding the SMRAM to all but the SMM agents, or the "closed" state 11 - Preserving the system integrity, or "locking" the SMRAM, such that the settings cannot be 12 perturbed by either boot service or runtime agents 13 14 Copyright (c) 2010, Intel Corporation. All rights reserved.<BR> 15 16 This program and the accompanying materials 17 are licensed and made available under the terms and conditions 18 of the BSD License which accompanies this distribution. The 19 full text of the license may be found at 20 http://opensource.org/licenses/bsd-license.php 21 22 THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS, 23 WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED. 24 25 **/ 26 27 #ifndef _SMM_ACCESS_PPI_H_ 28 #define _SMM_ACCESS_PPI_H_ 29 30 #define PEI_SMM_ACCESS_PPI_GUID \ 31 { 0x268f33a9, 0xcccd, 0x48be, { 0x88, 0x17, 0x86, 0x5, 0x3a, 0xc3, 0x2e, 0xd6 }} 32 33 typedef struct _PEI_SMM_ACCESS_PPI PEI_SMM_ACCESS_PPI; 34 35 /** 36 Opens the SMRAM area to be accessible by a PEIM driver. 37 38 This function "opens" SMRAM so that it is visible while not inside of SMM. The function should 39 return EFI_UNSUPPORTED if the hardware does not support hiding of SMRAM. The function 40 should return EFI_DEVICE_ERROR if the SMRAM configuration is locked. 41 42 @param PeiServices General purpose services available to every PEIM. 43 @param This The pointer to the SMM Access Interface. 44 @param DescriptorIndex The region of SMRAM to Open. 45 46 @retval EFI_SUCCESS The region was successfully opened. 47 @retval EFI_DEVICE_ERROR The region could not be opened because locked by chipset. 48 @retval EFI_INVALID_PARAMETER The descriptor index was out of bounds. 49 50 **/ 51 typedef 52 EFI_STATUS 53 (EFIAPI *PEI_SMM_OPEN)( 54 IN EFI_PEI_SERVICES **PeiServices, 55 IN PEI_SMM_ACCESS_PPI *This, 56 IN UINTN DescriptorIndex 57 ); 58 59 /** 60 Inhibits access to the SMRAM. 61 62 This function "closes" SMRAM so that it is not visible while outside of SMM. The function should 63 return EFI_UNSUPPORTED if the hardware does not support hiding of SMRAM. 64 65 @param PeiServices General purpose services available to every PEIM. 66 @param This The pointer to the SMM Access Interface. 67 @param DescriptorIndex The region of SMRAM to Close. 68 69 @retval EFI_SUCCESS The region was successfully closed. 70 @retval EFI_DEVICE_ERROR The region could not be closed because locked by chipset. 71 @retval EFI_INVALID_PARAMETER The descriptor index was out of bounds. 72 73 **/ 74 typedef 75 EFI_STATUS 76 (EFIAPI *PEI_SMM_CLOSE)( 77 IN EFI_PEI_SERVICES **PeiServices, 78 IN PEI_SMM_ACCESS_PPI *This, 79 IN UINTN DescriptorIndex 80 ); 81 82 /** 83 Inhibits access to the SMRAM. 84 85 This function prohibits access to the SMRAM region. This function is usually implemented such 86 that it is a write-once operation. 87 88 @param PeiServices General purpose services available to every PEIM. 89 @param This The pointer to the SMM Access Interface. 90 @param DescriptorIndex The region of SMRAM to Close. 91 92 @retval EFI_SUCCESS The region was successfully locked. 93 @retval EFI_DEVICE_ERROR The region could not be locked because at least 94 one range is still open. 95 @retval EFI_INVALID_PARAMETER The descriptor index was out of bounds. 96 97 **/ 98 typedef 99 EFI_STATUS 100 (EFIAPI *PEI_SMM_LOCK)( 101 IN EFI_PEI_SERVICES **PeiServices, 102 IN PEI_SMM_ACCESS_PPI *This, 103 IN UINTN DescriptorIndex 104 ); 105 106 /** 107 Queries the memory controller for the possible regions that will support SMRAM. 108 109 @param PeiServices General purpose services available to every PEIM. 110 @param This The pointer to the SmmAccessPpi Interface. 111 @param SmramMapSize The pointer to the variable containing size of the 112 buffer to contain the description information. 113 @param SmramMap The buffer containing the data describing the Smram 114 region descriptors. 115 116 @retval EFI_BUFFER_TOO_SMALL The user did not provide a sufficient buffer. 117 @retval EFI_SUCCESS The user provided a sufficiently-sized buffer. 118 119 **/ 120 typedef 121 EFI_STATUS 122 (EFIAPI *PEI_SMM_CAPABILITIES)( 123 IN EFI_PEI_SERVICES **PeiServices, 124 IN PEI_SMM_ACCESS_PPI *This, 125 IN OUT UINTN *SmramMapSize, 126 IN OUT EFI_SMRAM_DESCRIPTOR *SmramMap 127 ); 128 129 /// 130 /// EFI SMM Access PPI is used to control the visibility of the SMRAM on the platform. 131 /// It abstracts the location and characteristics of SMRAM. The expectation is 132 /// that the north bridge or memory controller would publish this PPI. 133 /// 134 struct _PEI_SMM_ACCESS_PPI { 135 PEI_SMM_OPEN Open; 136 PEI_SMM_CLOSE Close; 137 PEI_SMM_LOCK Lock; 138 PEI_SMM_CAPABILITIES GetCapabilities; 139 BOOLEAN LockState; 140 BOOLEAN OpenState; 141 }; 142 143 extern EFI_GUID gPeiSmmAccessPpiGuid; 144 145 #endif 146
