system76-edk2/MdeModulePkg/Universal/Variable/RuntimeDxe/Reclaim.c

/** @file
  Handles non-volatile variable store garbage collection, using FTW
  (Fault Tolerant Write) protocol.

Copyright (c) 2006 - 2015, Intel Corporation. All rights reserved.<BR>
SPDX-License-Identifier: BSD-2-Clause-Patent

**/

#include "Variable.h"

/**
  Gets LBA of block and offset by given address.

  This function gets the Logical Block Address (LBA) of a firmware
  volume block containing the given address, and the offset of the
  address on the block.

  @param  Address        Address which should be contained
                         by returned FVB handle.
  @param  Lba            Pointer to LBA for output.
  @param  Offset         Pointer to offset for output.

  @retval EFI_SUCCESS    LBA and offset successfully returned.
  @retval EFI_NOT_FOUND  Fail to find FVB handle by address.
  @retval EFI_ABORTED    Fail to find valid LBA and offset.

**/
EFI_STATUS
GetLbaAndOffsetByAddress (
  IN  EFI_PHYSICAL_ADDRESS   Address,
  OUT EFI_LBA                *Lba,
  OUT UINTN                  *Offset
  )
{
  EFI_STATUS                          Status;
  EFI_PHYSICAL_ADDRESS                FvbBaseAddress;
  EFI_FIRMWARE_VOLUME_BLOCK_PROTOCOL  *Fvb;
  EFI_FIRMWARE_VOLUME_HEADER          *FwVolHeader;
  EFI_FV_BLOCK_MAP_ENTRY              *FvbMapEntry;
  UINT32                              LbaIndex;

  Fvb     = NULL;
  *Lba    = (EFI_LBA) (-1);
  *Offset = 0;

  //
  // Get the proper FVB protocol.
  //
  Status = GetFvbInfoByAddress (Address, NULL, &Fvb);
  if (EFI_ERROR (Status)) {
    return Status;
  }

  //
  // Get the Base Address of FV.
  //
  Status = Fvb->GetPhysicalAddress (Fvb, &FvbBaseAddress);
  if (EFI_ERROR (Status)) {
    return Status;
  }

  FwVolHeader = (EFI_FIRMWARE_VOLUME_HEADER *) ((UINTN) FvbBaseAddress);

  //
  // Get the (LBA, Offset) of Address.
  //
  if ((FwVolHeader->FvLength) > (FwVolHeader->HeaderLength)) {
    //
    // BUGBUG: Assume one FV has one type of BlockLength.
    //
    FvbMapEntry = &FwVolHeader->BlockMap[0];
    for (LbaIndex = 1; LbaIndex <= FvbMapEntry->NumBlocks; LbaIndex += 1) {
      if (Address < (FvbBaseAddress + FvbMapEntry->Length * LbaIndex)) {
        //
        // Found the (Lba, Offset).
        //
        *Lba    = LbaIndex - 1;
        *Offset = (UINTN) (Address - (FvbBaseAddress + FvbMapEntry->Length * (LbaIndex - 1)));
        return EFI_SUCCESS;
     }
    }
  }

  return EFI_ABORTED;
}

/**
  Writes a buffer to variable storage space, in the working block.

  This function writes a buffer to variable storage space into a firmware
  volume block device. The destination is specified by parameter
  VariableBase. Fault Tolerant Write protocol is used for writing.

  @param  VariableBase   Base address of variable to write
  @param  VariableBuffer Point to the variable data buffer.

  @retval EFI_SUCCESS    The function completed successfully.
  @retval EFI_NOT_FOUND  Fail to locate Fault Tolerant Write protocol.
  @retval EFI_ABORTED    The function could not complete successfully.

**/
EFI_STATUS
FtwVariableSpace (
  IN EFI_PHYSICAL_ADDRESS   VariableBase,
  IN VARIABLE_STORE_HEADER  *VariableBuffer
  )
{
  EFI_STATUS                         Status;
  EFI_HANDLE                         FvbHandle;
  EFI_LBA                            VarLba;
  UINTN                              VarOffset;
  UINTN                              FtwBufferSize;
  EFI_FAULT_TOLERANT_WRITE_PROTOCOL  *FtwProtocol;

  //
  // Locate fault tolerant write protocol.
  //
  Status = GetFtwProtocol((VOID **) &FtwProtocol);
  if (EFI_ERROR (Status)) {
    return EFI_NOT_FOUND;
  }
  //
  // Locate Fvb handle by address.
  //
  Status = GetFvbInfoByAddress (VariableBase, &FvbHandle, NULL);
  if (EFI_ERROR (Status)) {
    return Status;
  }
  //
  // Get LBA and Offset by address.
  //
  Status = GetLbaAndOffsetByAddress (VariableBase, &VarLba, &VarOffset);
  if (EFI_ERROR (Status)) {
    return EFI_ABORTED;
  }

  FtwBufferSize = ((VARIABLE_STORE_HEADER *) ((UINTN) VariableBase))->Size;
  ASSERT (FtwBufferSize == VariableBuffer->Size);

  //
  // FTW write record.
  //
  Status = FtwProtocol->Write (
                          FtwProtocol,
                          VarLba,         // LBA
                          VarOffset,      // Offset
                          FtwBufferSize,  // NumBytes
                          NULL,           // PrivateData NULL
                          FvbHandle,      // Fvb Handle
                          (VOID *) VariableBuffer // write buffer
                          );

  return Status;
}