MdePkg/Include/Protocol/SmmAccess2.h

   1 /** @file
   2   EFI SMM Access2 Protocol as defined in the PI 1.2 specification.
   3
   4   This protocol 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 protocol.
   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) 2009, Intel Corporation
  15   All rights reserved. This program and the accompanying materials
  16   are licensed and made available under the terms and conditions of the BSD License
  17   which accompanies this distribution.  The full text of the license may be found at
  18   http://opensource.org/licenses/bsd-license.php
  19
  20   THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
  21   WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
  22
  23 **/
  24
  25 #ifndef _SMM_ACCESS2_H_
  26 #define _SMM_ACCESS2_H_
  27
  28 #include <PiDxe.h>
  29
  30 #define EFI_SMM_ACCESS2_PROTOCOL_GUID \
  31   { \
  32      0xc2702b74, 0x800c, 0x4131, {0x87, 0x46, 0x8f, 0xb5, 0xb8, 0x9c, 0xe4, 0xac } \
  33   }
  34
  35 ///
  36 /// SMRAM states and capabilities
  37 ///
  38 #define EFI_SMRAM_OPEN                  0x00000001
  39 #define EFI_SMRAM_CLOSED                0x00000002
  40 #define EFI_SMRAM_LOCKED                0x00000004
  41 #define EFI_CACHEABLE                   0x00000008
  42 #define EFI_ALLOCATED                   0x00000010
  43 #define EFI_NEEDS_TESTING               0x00000020
  44 #define EFI_NEEDS_ECC_INITIALIZATION    0x00000040
  45
  46 ///
  47 /// Structure describing a SMRAM region and its accessibility attributes
  48 ///
  49 typedef struct {
  50   ///
  51   /// Designates the physical address of the SMRAM in memory. This view of memory is
  52   /// the same as seen by I/O-based agents, for example, but it may not be the address seen
  53   /// by the processors.
  54   ///
  55   EFI_PHYSICAL_ADDRESS  PhysicalStart;
  56   ///
  57   /// Designates the address of the SMRAM, as seen by software executing on the
  58   /// processors. This address may or may not match PhysicalStart.
  59   ///
  60   EFI_PHYSICAL_ADDRESS  CpuStart;
  61   ///
  62   /// Describes the number of bytes in the SMRAM region.
  63   ///
  64   UINT64                PhysicalSize;
  65   ///
  66   /// Describes the accessibility attributes of the SMRAM.  These attributes include the
  67   /// hardware state (e.g., Open/Closed/Locked), capability (e.g., cacheable), logical
  68   /// allocation (e.g., allocated), and pre-use initialization (e.g., needs testing/ECC
  69   /// initialization).
  70   ///
  71   UINT64                RegionState;
  72 } EFI_SMRAM_DESCRIPTOR;
  73
  74 typedef struct _EFI_SMM_ACCESS2_PROTOCOL  EFI_SMM_ACCESS2_PROTOCOL;
  75
  76 /**
  77   Opens the SMRAM area to be accessible by a boot-service driver.
  78
  79   This function "opens" SMRAM so that it is visible while not inside of SMM. The function should
  80   return EFI_UNSUPPORTED if the hardware does not support hiding of SMRAM. The function
  81   should return EFI_DEVICE_ERROR if the SMRAM configuration is locked.
  82
  83   @param[in] This           The EFI_SMM_ACCESS2_PROTOCOL instance.
  84
  85   @retval EFI_SUCCESS       The operation was successful.
  86   @retval EFI_UNSUPPORTED   The system does not support opening and closing of SMRAM.
  87   @retval EFI_DEVICE_ERROR  SMRAM cannot be opened, perhaps because it is locked.
  88 **/
  89 typedef
  90 EFI_STATUS
  91 (EFIAPI *EFI_SMM_OPEN)(
  92   IN EFI_SMM_ACCESS2_PROTOCOL  *This
  93   );
  94
  95 /**
  96   Inhibits access to the SMRAM.
  97
  98   This function "closes" SMRAM so that it is not visible while outside of SMM. The function should
  99   return EFI_UNSUPPORTED if the hardware does not support hiding of SMRAM.
 100
 101   @param[in] This           The EFI_SMM_ACCESS2_PROTOCOL instance.
 102
 103   @retval EFI_SUCCESS       The operation was successful.
 104   @retval EFI_UNSUPPORTED   The system does not support opening and closing of SMRAM.
 105   @retval EFI_DEVICE_ERROR  SMRAM cannot be closed.
 106 **/
 107 typedef
 108 EFI_STATUS
 109 (EFIAPI *EFI_SMM_CLOSE)(
 110   IN EFI_SMM_ACCESS2_PROTOCOL  *This
 111   );
 112
 113 /**
 114   Inhibits access to the SMRAM.
 115
 116   This function prohibits access to the SMRAM region.  This function is usually implemented such
 117   that it is a write-once operation.
 118
 119   @param[in] This          The EFI_SMM_ACCESS2_PROTOCOL instance.
 120
 121   @retval EFI_SUCCESS      The device was successfully locked.
 122   @retval EFI_UNSUPPORTED  The system does not support locking of SMRAM.
 123 **/
 124 typedef
 125 EFI_STATUS
 126 (EFIAPI *EFI_SMM_LOCK)(
 127   IN EFI_SMM_ACCESS2_PROTOCOL  *This
 128   );
 129
 130 /**
 131   Queries the memory controller for the possible regions that will support SMRAM.
 132
 133   @param[in]     This           The EFI_SMM_ACCESS2_PROTOCOL instance.
 134   @param[in,out] SmramMapSize   A pointer to the size, in bytes, of the SmramMemoryMap buffer.
 135   @param[in,out] SmramMap       A pointer to the buffer in which firmware places the current memory map.
 136
 137   @retval EFI_SUCCESS           The chipset supported the given resource.
 138   @retval EFI_BUFFER_TOO_SMALL  The SmramMap parameter was too small.  The current buffer size
 139                                 needed to hold the memory map is returned in SmramMapSize.
 140 **/
 141 typedef
 142 EFI_STATUS
 143 (EFIAPI *EFI_SMM_CAPABILITIES)(
 144   IN CONST EFI_SMM_ACCESS2_PROTOCOL  *This,
 145   IN OUT UINTN                       *SmramMapSize,
 146   IN OUT EFI_SMRAM_DESCRIPTOR        *SmramMap
 147   );
 148
 149 ///
 150 ///  EFI SMM Access2 Protocol is used to control the visibility of the SMRAM on the platform.
 151 ///  It abstracts the location and characteristics of SMRAM.  The expectation is
 152 ///  that the north bridge or memory controller would publish this protocol.
 153 ///
 154 struct _EFI_SMM_ACCESS2_PROTOCOL {
 155   EFI_SMM_OPEN          Open;
 156   EFI_SMM_CLOSE         Close;
 157   EFI_SMM_LOCK          Lock;
 158   EFI_SMM_CAPABILITIES  GetCapabilities;
 159   ///
 160   /// Indicates the current state of the SMRAM. Set to TRUE if SMRAM is locked.
 161   ///
 162   BOOLEAN               LockState;
 163   ///
 164   /// Indicates the current state of the SMRAM. Set to TRUE if SMRAM is open.
 165   ///
 166   BOOLEAN               OpenState;
 167 };
 168
 169 extern EFI_GUID gEfiSmmAccess2ProtocolGuid;
 170
 171 #endif
 172