SmmAccessDxe.c

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#include "SmmAccessDxe.h"
 
SMM_ACCESS_PRIVATE_DATA  mSmmAccess;
 
VOID
SyncRegionState2SmramDesc (
  IN BOOLEAN  OrLogic,
  IN UINT64   Value
  )
{
  UINT32  Index;
 
  for (Index = 0; Index < mSmmAccess.NumberRegions; Index++) {
    if (OrLogic) {
      mSmmAccess.SmramDesc[Index].RegionState |= Value;
    } else {
      mSmmAccess.SmramDesc[Index].RegionState &= Value;
    }
  }
}
 
EFI_STATUS
EFIAPI
Open (
  IN EFI_SMM_ACCESS2_PROTOCOL  *This
  )
{
  if ((mSmmAccess.SmmRegionState & EFI_SMRAM_LOCKED) != 0) {
    //
    // Cannot open a "locked" region
    //
    DEBUG ((DEBUG_INFO, "Cannot open the locked SMRAM Region\n"));
    return EFI_DEVICE_ERROR;
  }
 
  mSmmAccess.SmmRegionState &= ~(EFI_SMRAM_CLOSED | EFI_ALLOCATED);
  SyncRegionState2SmramDesc (FALSE, (UINT64)(UINTN)(~(EFI_SMRAM_CLOSED | EFI_ALLOCATED)));
 
  mSmmAccess.SmmRegionState |= EFI_SMRAM_OPEN;
  SyncRegionState2SmramDesc (TRUE, EFI_SMRAM_OPEN);
  mSmmAccess.SmmAccess.OpenState = TRUE;
 
  return EFI_SUCCESS;
}
 
EFI_STATUS
EFIAPI
Close (
  IN EFI_SMM_ACCESS2_PROTOCOL  *This
  )
{
  if ((mSmmAccess.SmmRegionState & EFI_SMRAM_LOCKED) != 0) {
    //
    // Cannot close a "locked" region
    //
    DEBUG ((DEBUG_INFO, "Cannot close the locked SMRAM Region\n"));
    return EFI_DEVICE_ERROR;
  }
 
  if ((mSmmAccess.SmmRegionState & EFI_SMRAM_CLOSED) != 0) {
    return EFI_DEVICE_ERROR;
  }
 
  mSmmAccess.SmmRegionState &= ~EFI_SMRAM_OPEN;
  SyncRegionState2SmramDesc (FALSE, (UINT64)(UINTN)(~EFI_SMRAM_OPEN));
 
  mSmmAccess.SmmRegionState |= (EFI_SMRAM_CLOSED | EFI_ALLOCATED);
  SyncRegionState2SmramDesc (TRUE, EFI_SMRAM_CLOSED | EFI_ALLOCATED);
 
  mSmmAccess.SmmAccess.OpenState = FALSE;
 
  return EFI_SUCCESS;
}
 
EFI_STATUS
EFIAPI
Lock (
  IN EFI_SMM_ACCESS2_PROTOCOL  *This
  )
{
  if (mSmmAccess.SmmAccess.OpenState) {
    DEBUG ((DEBUG_INFO, "Cannot lock SMRAM when it is still open\n"));
    return EFI_DEVICE_ERROR;
  }
 
  mSmmAccess.SmmRegionState |= EFI_SMRAM_LOCKED;
  SyncRegionState2SmramDesc (TRUE, EFI_SMRAM_LOCKED);
  mSmmAccess.SmmAccess.LockState = TRUE;
  return EFI_SUCCESS;
}
 
EFI_STATUS
EFIAPI
GetCapabilities (
  IN CONST EFI_SMM_ACCESS2_PROTOCOL  *This,
  IN OUT   UINTN                     *SmramMapSize,
  IN OUT   EFI_SMRAM_DESCRIPTOR      *SmramMap
  )
{
  EFI_STATUS  Status;
  UINTN       NecessaryBufferSize;
 
  NecessaryBufferSize = mSmmAccess.NumberRegions * sizeof (EFI_SMRAM_DESCRIPTOR);
  if (*SmramMapSize < NecessaryBufferSize) {
    Status = EFI_BUFFER_TOO_SMALL;
  } else {
    CopyMem (SmramMap, mSmmAccess.SmramDesc, NecessaryBufferSize);
    Status = EFI_SUCCESS;
  }
 
  *SmramMapSize = NecessaryBufferSize;
  return Status;
}
 
EFI_STATUS
EFIAPI
SmmAccessEntryPoint (
  IN EFI_HANDLE        ImageHandle,
  IN EFI_SYSTEM_TABLE  *SystemTable
  )
{
  EFI_STATUS                      Status;
  EFI_HOB_GUID_TYPE               *GuidHob;
  UINT32                          SmmRegionNum;
  EFI_SMRAM_HOB_DESCRIPTOR_BLOCK  *SmramHob;
  UINT32                          Index;
 
  //
  // Get SMRAM info HOB
  //
  GuidHob = GetFirstGuidHob (&gEfiSmmSmramMemoryGuid);
  if (GuidHob == NULL) {
    DEBUG ((DEBUG_INFO, "SMRAM HOB NOT found\n"));
    return EFI_NOT_FOUND;
  }
 
  SmramHob             = (EFI_SMRAM_HOB_DESCRIPTOR_BLOCK *)GET_GUID_HOB_DATA (GuidHob);
  SmmRegionNum         = SmramHob->NumberOfSmmReservedRegions;
  mSmmAccess.SmramDesc = AllocateZeroPool (sizeof (EFI_SMRAM_DESCRIPTOR) * SmmRegionNum);
  if (mSmmAccess.SmramDesc == NULL) {
    return EFI_OUT_OF_RESOURCES;
  }
 
  CopyMem (mSmmAccess.SmramDesc, &SmramHob->Descriptor, sizeof (EFI_SMRAM_DESCRIPTOR) * SmmRegionNum);
 
  DEBUG ((DEBUG_INFO, "NumberOfSmmReservedRegions = 0x%x\n", SmmRegionNum));
  for (Index = 0; Index < SmmRegionNum; Index++) {
    DEBUG ((
      DEBUG_INFO,
      "%d: base=0x%x, size = 0x%x, State=0x%x\n",
      Index,
      SmramHob->Descriptor[Index].PhysicalStart,
      SmramHob->Descriptor[Index].PhysicalSize,
      SmramHob->Descriptor[Index].RegionState
      ));
    mSmmAccess.SmramDesc[Index].RegionState &= EFI_ALLOCATED;
    mSmmAccess.SmramDesc[Index].RegionState |= EFI_SMRAM_CLOSED | EFI_CACHEABLE;
  }
 
  mSmmAccess.Signature                 = SMM_ACCESS_PRIVATE_DATA_SIGNATURE;
  mSmmAccess.NumberRegions             = SmmRegionNum;
  mSmmAccess.SmmAccess.Open            = Open;
  mSmmAccess.SmmAccess.Close           = Close;
  mSmmAccess.SmmAccess.Lock            = Lock;
  mSmmAccess.SmmAccess.GetCapabilities = GetCapabilities;
  mSmmAccess.SmmAccess.LockState       = FALSE;
  mSmmAccess.SmmAccess.OpenState       = FALSE;
  mSmmAccess.SmmRegionState            = EFI_SMRAM_CLOSED;
 
  Status = gBS->InstallMultipleProtocolInterfaces (
                  &mSmmAccess.Handle,
                  &gEfiSmmAccess2ProtocolGuid,
                  &mSmmAccess.SmmAccess,
                  NULL
                  );
 
  return Status;
}