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system76-edk2/UefiPayloadPkg/SmmStoreFvb/SmmStoreFvbRuntimeDxe.c
Sean Rhodes 1f31c0e81e UefiPayloadPkg: Add support for Firmware Volume Block Protocol 
This adds support for FVB in order to support a platform independent
and non-volatile variable store on UefiPayloadPkg. The variable store
makes use the SmmStoreLib to provide an unauthenticed variable store.

Since commit bc744f5893fc4d53275ed26dd8d968011c6a09c1 coreboot supports
the SMMSTORE v2 feature. It implements a SMI handler that is able to
write, read and erase pages in the boot media (SPI flash).
The communication is done using a fixed communication buffer that is
allocated in CBMEM. The existence of this optional feature is advertised
by a coreboot table.
When the SMMSTORE feature is not available the variable emulation is used
by setting PcdEmuVariableNvModeEnable to TRUE.

The DXE component provides runtime services and takes care of virtual to
physical mapping the communication buffers between SMM and OS.

The contents of the variable store can be accessed and modified by any
priviledged application. As authentication is done by runtime services
only the store shouldn't be used to store authenticated variables.

Tested on Linux and Windows 10 on real hardware.
Currently this cannot be tested on coreboot and qemu as it doesn't support
the SMMSTORE on qemu.

Cc: Guo Dong <guo.dong@intel.com>
Cc: Ray Ni <ray.ni@intel.com>
Cc: Maurice Ma <maurice.ma@intel.com>
Cc: Benjamin You <benjamin.you@intel.com>
Signed-off-by: Patrick Rudolph <patrick.rudolph@9elements.com>
Signed-off-by: Sean Rhodes <sean@starlabs.systems>
Change-Id: I79a234275e25961869edf959cfbf4f8d17df2383
2022-06-03 09:03:42 -06:00

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/** @file SmmStoreFvbRuntimeDxe.c
Copyright (c) 2022, 9elements GmbH<BR>
SPDX-License-Identifier: BSD-2-Clause-Patent
**/
#include <PiDxe.h>
#include <Library/PcdLib.h>
#include <Library/BaseLib.h>
#include <Library/HobLib.h>
#include <Library/UefiLib.h>
#include <Library/BaseMemoryLib.h>
#include <Library/MemoryAllocationLib.h>
#include <Library/DxeServicesTableLib.h>
#include <Library/UefiBootServicesTableLib.h>
#include <Library/SmmStoreLib.h>
#include <Guid/VariableFormat.h>
#include <Guid/SystemNvDataGuid.h>
#include <Guid/NvVarStoreFormatted.h>
#include "SmmStoreFvbRuntime.h"
///
/// The Firmware Volume Block Protocol is the low-level interface
/// to a firmware volume. File-level access to a firmware volume
/// should not be done using the Firmware Volume Block Protocol.
/// Normal access to a firmware volume must use the Firmware
/// Volume Protocol. Typically, only the file system driver that
/// produces the Firmware Volume Protocol will bind to the
/// Firmware Volume Block Protocol.
///
/**
Initialises the FV Header and Variable Store Header
to support variable operations.
@param[in] Instance - Pointer to SmmStore instance
**/
EFI_STATUS
InitializeFvAndVariableStoreHeaders (
IN SMMSTORE_INSTANCE *Instance
)
{
EFI_STATUS Status;
VOID *Headers;
UINTN HeadersLength;
EFI_FIRMWARE_VOLUME_HEADER *FirmwareVolumeHeader;
VARIABLE_STORE_HEADER *VariableStoreHeader;
UINT32 NvStorageFtwSpareSize;
UINT32 NvStorageFtwWorkingSize;
UINT32 NvStorageVariableSize;
UINT64 NvStorageFtwSpareBase;
UINT64 NvStorageFtwWorkingBase;
UINT64 NvStorageVariableBase;
HeadersLength = sizeof (EFI_FIRMWARE_VOLUME_HEADER) + sizeof (EFI_FV_BLOCK_MAP_ENTRY) + sizeof (VARIABLE_STORE_HEADER);
Headers = AllocateZeroPool (HeadersLength);
NvStorageFtwWorkingSize = PcdGet32 (PcdFlashNvStorageFtwWorkingSize);
NvStorageFtwSpareSize = PcdGet32 (PcdFlashNvStorageFtwSpareSize);
NvStorageVariableSize = PcdGet32 (PcdFlashNvStorageVariableSize);
NvStorageFtwSpareBase = (PcdGet64 (PcdFlashNvStorageFtwSpareBase64) != 0) ?
PcdGet64 (PcdFlashNvStorageFtwSpareBase64) : PcdGet32 (PcdFlashNvStorageFtwSpareBase);
NvStorageFtwWorkingBase = (PcdGet64 (PcdFlashNvStorageFtwWorkingBase64) != 0) ?
PcdGet64 (PcdFlashNvStorageFtwWorkingBase64) : PcdGet32 (PcdFlashNvStorageFtwWorkingBase);
NvStorageVariableBase = (PcdGet64 (PcdFlashNvStorageVariableBase64) != 0) ?
PcdGet64 (PcdFlashNvStorageVariableBase64) : PcdGet32 (PcdFlashNvStorageVariableBase);
// FirmwareVolumeHeader->FvLength is declared to have the Variable area AND the FTW working area AND the FTW Spare contiguous.
if ((NvStorageVariableBase + NvStorageVariableSize) != NvStorageFtwWorkingBase) {
DEBUG ((
DEBUG_ERROR,
"%a: NvStorageFtwWorkingBase is not contiguous with NvStorageVariableBase region\n",
__FUNCTION__
));
return EFI_INVALID_PARAMETER;
}
if ((NvStorageFtwWorkingBase + NvStorageFtwWorkingSize) != NvStorageFtwSpareBase) {
DEBUG ((
DEBUG_ERROR,
"%a: NvStorageFtwSpareBase is not contiguous with NvStorageFtwWorkingBase region\n",
__FUNCTION__
));
return EFI_INVALID_PARAMETER;
}
// Check if the size of the area is at least one block size
if ((NvStorageVariableSize <= 0) || (NvStorageVariableSize / Instance->BlockSize <= 0)) {
DEBUG ((
DEBUG_ERROR,
"%a: NvStorageVariableSize is 0x%x, should be atleast one block size\n",
__FUNCTION__,
NvStorageVariableSize
));
return EFI_INVALID_PARAMETER;
}
if ((NvStorageFtwWorkingSize <= 0) || (NvStorageFtwWorkingSize / Instance->BlockSize <= 0)) {
DEBUG ((
DEBUG_ERROR,
"%a: NvStorageFtwWorkingSize is 0x%x, should be atleast one block size\n",
__FUNCTION__,
NvStorageFtwWorkingSize
));
return EFI_INVALID_PARAMETER;
}
if ((NvStorageFtwSpareSize <= 0) || (NvStorageFtwSpareSize / Instance->BlockSize <= 0)) {
DEBUG ((
DEBUG_ERROR,
"%a: NvStorageFtwSpareSize is 0x%x, should be atleast one block size\n",
__FUNCTION__,
NvStorageFtwSpareSize
));
return EFI_INVALID_PARAMETER;
}
// Ensure the Variable area Base Addresses are aligned on a block size boundaries
if ((NvStorageVariableBase % Instance->BlockSize != 0) ||
(NvStorageFtwWorkingBase % Instance->BlockSize != 0) ||
(NvStorageFtwSpareBase % Instance->BlockSize != 0))
{
DEBUG ((DEBUG_ERROR, "%a: NvStorage Base addresses must be aligned to block size boundaries", __FUNCTION__));
return EFI_INVALID_PARAMETER;
}
//
// EFI_FIRMWARE_VOLUME_HEADER
//
FirmwareVolumeHeader = (EFI_FIRMWARE_VOLUME_HEADER *)Headers;
CopyGuid (&FirmwareVolumeHeader->FileSystemGuid, &gEfiSystemNvDataFvGuid);
FirmwareVolumeHeader->FvLength =
PcdGet32 (PcdFlashNvStorageVariableSize) +
PcdGet32 (PcdFlashNvStorageFtwWorkingSize) +
PcdGet32 (PcdFlashNvStorageFtwSpareSize);
FirmwareVolumeHeader->Signature = EFI_FVH_SIGNATURE;
FirmwareVolumeHeader->Attributes = (EFI_FVB_ATTRIBUTES_2)(
EFI_FVB2_READ_ENABLED_CAP | // Reads may be enabled
EFI_FVB2_READ_STATUS | // Reads are currently enabled
EFI_FVB2_STICKY_WRITE | // A block erase is required to flip bits into EFI_FVB2_ERASE_POLARITY
EFI_FVB2_MEMORY_MAPPED | // It is memory mapped
EFI_FVB2_ERASE_POLARITY | // After erasure all bits take this value (i.e. '1')
EFI_FVB2_WRITE_STATUS | // Writes are currently enabled
EFI_FVB2_WRITE_ENABLED_CAP // Writes may be enabled
);
FirmwareVolumeHeader->HeaderLength = sizeof (EFI_FIRMWARE_VOLUME_HEADER) + sizeof (EFI_FV_BLOCK_MAP_ENTRY);
FirmwareVolumeHeader->Revision = EFI_FVH_REVISION;
FirmwareVolumeHeader->BlockMap[0].NumBlocks = Instance->LastBlock + 1;
FirmwareVolumeHeader->BlockMap[0].Length = Instance->BlockSize;
FirmwareVolumeHeader->BlockMap[1].NumBlocks = 0;
FirmwareVolumeHeader->BlockMap[1].Length = 0;
FirmwareVolumeHeader->Checksum = CalculateCheckSum16 ((UINT16 *)FirmwareVolumeHeader, FirmwareVolumeHeader->HeaderLength);
//
// VARIABLE_STORE_HEADER
//
VariableStoreHeader = (VARIABLE_STORE_HEADER *)((UINTN)Headers + FirmwareVolumeHeader->HeaderLength);
CopyGuid (&VariableStoreHeader->Signature, &gEfiVariableGuid);
VariableStoreHeader->Size = PcdGet32 (PcdFlashNvStorageVariableSize) - FirmwareVolumeHeader->HeaderLength;
VariableStoreHeader->Format = VARIABLE_STORE_FORMATTED;
VariableStoreHeader->State = VARIABLE_STORE_HEALTHY;
// Install the combined super-header in the NorFlash
Status = FvbWrite (&Instance->FvbProtocol, 0, 0, &HeadersLength, Headers);
FreePool (Headers);
return Status;
}
/**
Check the integrity of firmware volume header.
@retval EFI_SUCCESS - The firmware volume is consistent
@retval EFI_NOT_FOUND - The firmware volume has been corrupted.
**/
EFI_STATUS
ValidateFvHeader (
VOID
)
{
UINT16 Checksum;
EFI_FIRMWARE_VOLUME_HEADER *FwVolHeader;
VARIABLE_STORE_HEADER *VariableStoreHeader;
UINTN VariableStoreLength;
UINTN FvLength;
EFI_STATUS TempStatus;
UINTN BufferSize;
UINTN BufferSizeReqested;
BufferSizeReqested = sizeof (EFI_FIRMWARE_VOLUME_HEADER);
FwVolHeader = (EFI_FIRMWARE_VOLUME_HEADER *)AllocatePool (BufferSizeReqested);
if (!FwVolHeader) {
return EFI_OUT_OF_RESOURCES;
}
BufferSize = BufferSizeReqested;
TempStatus = SmmStoreLibRead (0, 0, &BufferSize, (UINT8 *)FwVolHeader);
if (EFI_ERROR (TempStatus) || (BufferSizeReqested != BufferSize)) {
FreePool (FwVolHeader);
return EFI_DEVICE_ERROR;
}
FvLength = PcdGet32 (PcdFlashNvStorageVariableSize) + PcdGet32 (PcdFlashNvStorageFtwWorkingSize) +
PcdGet32 (PcdFlashNvStorageFtwSpareSize);
//
// Verify the header revision, header signature, length
// Length of FvBlock cannot be 2**64-1
// HeaderLength cannot be an odd number
//
if ( (FwVolHeader->Revision != EFI_FVH_REVISION)
|| (FwVolHeader->Signature != EFI_FVH_SIGNATURE)
|| (FwVolHeader->FvLength != FvLength)
)
{
DEBUG ((
DEBUG_INFO,
"%a: No Firmware Volume header present\n",
__FUNCTION__
));
FreePool (FwVolHeader);
return EFI_NOT_FOUND;
}
// Check the Firmware Volume Guid
if ( CompareGuid (&FwVolHeader->FileSystemGuid, &gEfiSystemNvDataFvGuid) == FALSE ) {
DEBUG ((
DEBUG_INFO,
"%a: Firmware Volume Guid non-compatible\n",
__FUNCTION__
));
FreePool (FwVolHeader);
return EFI_NOT_FOUND;
}
BufferSizeReqested = FwVolHeader->HeaderLength;
FreePool (FwVolHeader);
FwVolHeader = (EFI_FIRMWARE_VOLUME_HEADER *)AllocatePool (BufferSizeReqested);
if (!FwVolHeader) {
return EFI_OUT_OF_RESOURCES;
}
BufferSize = BufferSizeReqested;
TempStatus = SmmStoreLibRead (0, 0, &BufferSize, (UINT8 *)FwVolHeader);
if (EFI_ERROR (TempStatus) || (BufferSizeReqested != BufferSize)) {
FreePool (FwVolHeader);
return EFI_DEVICE_ERROR;
}
// Verify the header checksum
Checksum = CalculateSum16 ((UINT16 *)FwVolHeader, FwVolHeader->HeaderLength);
if (Checksum != 0) {
DEBUG ((
DEBUG_INFO,
"%a: FV checksum is invalid (Checksum:0x%X)\n",
__FUNCTION__,
Checksum
));
FreePool (FwVolHeader);
return EFI_NOT_FOUND;
}
BufferSizeReqested = sizeof (VARIABLE_STORE_HEADER);
VariableStoreHeader = (VARIABLE_STORE_HEADER *)AllocatePool (BufferSizeReqested);
if (!VariableStoreHeader) {
return EFI_OUT_OF_RESOURCES;
}
BufferSize = BufferSizeReqested;
TempStatus = SmmStoreLibRead (0, FwVolHeader->HeaderLength, &BufferSize, (UINT8 *)VariableStoreHeader);
if (EFI_ERROR (TempStatus) || (BufferSizeReqested != BufferSize)) {
FreePool (VariableStoreHeader);
FreePool (FwVolHeader);
return EFI_DEVICE_ERROR;
}
// Check the Variable Store Guid
if (!CompareGuid (&VariableStoreHeader->Signature, &gEfiVariableGuid) &&
!CompareGuid (&VariableStoreHeader->Signature, &gEfiAuthenticatedVariableGuid))
{
DEBUG ((
DEBUG_INFO,
"%a: Variable Store Guid non-compatible\n",
__FUNCTION__
));
FreePool (FwVolHeader);
FreePool (VariableStoreHeader);
return EFI_NOT_FOUND;
}
VariableStoreLength = PcdGet32 (PcdFlashNvStorageVariableSize) - FwVolHeader->HeaderLength;
if (VariableStoreHeader->Size != VariableStoreLength) {
DEBUG ((
DEBUG_INFO,
"%a: Variable Store Length does not match\n",
__FUNCTION__
));
FreePool (FwVolHeader);
FreePool (VariableStoreHeader);
return EFI_NOT_FOUND;
}
FreePool (FwVolHeader);
FreePool (VariableStoreHeader);
return EFI_SUCCESS;
}
/**
The GetAttributes() function retrieves the attributes and
current settings of the block.
@param This Indicates the EFI_FIRMWARE_VOLUME_BLOCK2_PROTOCOL instance.
@param Attributes Pointer to EFI_FVB_ATTRIBUTES_2 in which the attributes and
current settings are returned.
Type EFI_FVB_ATTRIBUTES_2 is defined in EFI_FIRMWARE_VOLUME_HEADER.
@retval EFI_SUCCESS The firmware volume attributes were returned.
**/
EFI_STATUS
EFIAPI
FvbGetAttributes (
IN CONST EFI_FIRMWARE_VOLUME_BLOCK2_PROTOCOL *This,
OUT EFI_FVB_ATTRIBUTES_2 *Attributes
)
{
EFI_FVB_ATTRIBUTES_2 FlashFvbAttributes;
FlashFvbAttributes = (EFI_FVB_ATTRIBUTES_2)(
EFI_FVB2_READ_STATUS | // Reads are currently enabled
EFI_FVB2_WRITE_STATUS | // Writes are enabled
EFI_FVB2_STICKY_WRITE | // A block erase is required to flip bits into EFI_FVB2_ERASE_POLARITY
EFI_FVB2_MEMORY_MAPPED | // It is memory mapped
EFI_FVB2_ERASE_POLARITY // After erasure all bits take this value (i.e. '1')
);
*Attributes = FlashFvbAttributes;
DEBUG ((DEBUG_BLKIO, "FvbGetAttributes(0x%X)\n", *Attributes));
return EFI_SUCCESS;
}
/**
The SetAttributes() function sets configurable firmware volume attributes
and returns the new settings of the firmware volume.
@param This Indicates the EFI_FIRMWARE_VOLUME_BLOCK2_PROTOCOL instance.
@param Attributes On input, Attributes is a pointer to EFI_FVB_ATTRIBUTES_2
that contains the desired firmware volume settings.
On successful return, it contains the new settings of
the firmware volume.
Type EFI_FVB_ATTRIBUTES_2 is defined in EFI_FIRMWARE_VOLUME_HEADER.
@retval EFI_SUCCESS The firmware volume attributes were returned.
@retval EFI_INVALID_PARAMETER The attributes requested are in conflict with the capabilities
as declared in the firmware volume header.
**/
EFI_STATUS
EFIAPI
FvbSetAttributes (
IN CONST EFI_FIRMWARE_VOLUME_BLOCK2_PROTOCOL *This,
IN OUT EFI_FVB_ATTRIBUTES_2 *Attributes
)
{
DEBUG ((DEBUG_ERROR, "FvbSetAttributes(0x%X) is not supported\n", *Attributes));
return EFI_UNSUPPORTED;
}
/**
The GetPhysicalAddress() function retrieves the base address of
a memory-mapped firmware volume. This function should be called
only for memory-mapped firmware volumes.
@param This Indicates the EFI_FIRMWARE_VOLUME_BLOCK2_PROTOCOL instance.
@param Address Pointer to a caller-allocated
EFI_PHYSICAL_ADDRESS that, on successful
return from GetPhysicalAddress(), contains the
base address of the firmware volume.
@retval EFI_SUCCESS The firmware volume base address was returned.
@retval EFI_NOT_SUPPORTED The firmware volume is not memory mapped.
**/
EFI_STATUS
EFIAPI
FvbGetPhysicalAddress (
IN CONST EFI_FIRMWARE_VOLUME_BLOCK2_PROTOCOL *This,
OUT EFI_PHYSICAL_ADDRESS *Address
)
{
SMMSTORE_INSTANCE *Instance;
Instance = INSTANCE_FROM_FVB_THIS (This);
ASSERT (Address != NULL);
*Address = Instance->MmioAddress;
return EFI_SUCCESS;
}
/**
The GetBlockSize() function retrieves the size of the requested
block. It also returns the number of additional blocks with
the identical size. The GetBlockSize() function is used to
retrieve the block map (see EFI_FIRMWARE_VOLUME_HEADER).
@param This Indicates the EFI_FIRMWARE_VOLUME_BLOCK2_PROTOCOL instance.
@param Lba Indicates the block for which to return the size.
@param BlockSize Pointer to a caller-allocated UINTN in which
the size of the block is returned.
@param NumberOfBlocks Pointer to a caller-allocated UINTN in
which the number of consecutive blocks,
starting with Lba, is returned. All
blocks in this range have a size of
BlockSize.
@retval EFI_SUCCESS The firmware volume base address was returned.
@retval EFI_INVALID_PARAMETER The requested LBA is out of range.
**/
EFI_STATUS
EFIAPI
FvbGetBlockSize (
IN CONST EFI_FIRMWARE_VOLUME_BLOCK2_PROTOCOL *This,
IN EFI_LBA Lba,
OUT UINTN *BlockSize,
OUT UINTN *NumberOfBlocks
)
{
EFI_STATUS Status;
SMMSTORE_INSTANCE *Instance;
Instance = INSTANCE_FROM_FVB_THIS (This);
DEBUG ((DEBUG_BLKIO, "FvbGetBlockSize(Lba=%ld, BlockSize=0x%x, LastBlock=%ld)\n", Lba, Instance->BlockSize, Instance->LastBlock));
if (Lba > Instance->LastBlock) {
DEBUG ((DEBUG_ERROR, "FvbGetBlockSize: ERROR - Parameter LBA %ld is beyond the last Lba (%ld).\n", Lba, Instance->LastBlock));
Status = EFI_INVALID_PARAMETER;
} else {
*BlockSize = (UINTN)Instance->BlockSize;
*NumberOfBlocks = (UINTN)(Instance->LastBlock - Lba + 1);
DEBUG ((DEBUG_BLKIO, "FvbGetBlockSize: *BlockSize=0x%x, *NumberOfBlocks=0x%x.\n", *BlockSize, *NumberOfBlocks));
Status = EFI_SUCCESS;
}
return Status;
}
/**
Reads the specified number of bytes into a buffer from the specified block.
The Read() function reads the requested number of bytes from the
requested block and stores them in the provided buffer.
Implementations should be mindful that the firmware volume
might be in the ReadDisabled state. If it is in this state,
the Read() function must return the status code
EFI_ACCESS_DENIED without modifying the contents of the
buffer. The Read() function must also prevent spanning block
boundaries. If a read is requested that would span a block
boundary, the read must read up to the boundary but not
beyond. The output parameter NumBytes must be set to correctly
indicate the number of bytes actually read. The caller must be
aware that a read may be partially completed.
@param This Indicates the EFI_FIRMWARE_VOLUME_BLOCK2_PROTOCOL instance.
@param Lba The starting logical block index from which to read.
@param Offset Offset into the block at which to begin reading.
@param NumBytes Pointer to a UINTN.
At entry, *NumBytes contains the total size of the buffer.
At exit, *NumBytes contains the total number of bytes read.
@param Buffer Pointer to a caller-allocated buffer that will be used
to hold the data that is read.
@retval EFI_SUCCESS The firmware volume was read successfully, and contents are
in Buffer.
@retval EFI_BAD_BUFFER_SIZE Read attempted across an LBA boundary.
On output, NumBytes contains the total number of bytes
returned in Buffer.
@retval EFI_ACCESS_DENIED The firmware volume is in the ReadDisabled state.
@retval EFI_DEVICE_ERROR The block device is not functioning correctly and could not be read.
**/
EFI_STATUS
EFIAPI
FvbRead (
IN CONST EFI_FIRMWARE_VOLUME_BLOCK2_PROTOCOL *This,
IN EFI_LBA Lba,
IN UINTN Offset,
IN OUT UINTN *NumBytes,
IN OUT UINT8 *Buffer
)
{
UINTN BlockSize;
SMMSTORE_INSTANCE *Instance;
Instance = INSTANCE_FROM_FVB_THIS (This);
DEBUG ((DEBUG_BLKIO, "FvbRead(Parameters: Lba=%ld, Offset=0x%x, *NumBytes=0x%x, Buffer @ 0x%08x)\n", Lba, Offset, *NumBytes, Buffer));
// Cache the block size to avoid de-referencing pointers all the time
BlockSize = Instance->BlockSize;
// The read must not span block boundaries.
// We need to check each variable individually because adding two large values together overflows.
if ((Offset >= BlockSize) ||
(*NumBytes > BlockSize) ||
((Offset + *NumBytes) > BlockSize))
{
DEBUG ((DEBUG_ERROR, "FvbRead: ERROR - EFI_BAD_BUFFER_SIZE: (Offset=0x%x + NumBytes=0x%x) > BlockSize=0x%x\n", Offset, *NumBytes, BlockSize));
return EFI_BAD_BUFFER_SIZE;
}
// We must have some bytes to read
if (*NumBytes == 0) {
return EFI_BAD_BUFFER_SIZE;
}
return SmmStoreLibRead (Lba, Offset, NumBytes, Buffer);
}
/**
Writes the specified number of bytes from the input buffer to the block.
The Write() function writes the specified number of bytes from
the provided buffer to the specified block and offset. If the
firmware volume is sticky write, the caller must ensure that
all the bits of the specified range to write are in the
EFI_FVB_ERASE_POLARITY state before calling the Write()
function, or else the result will be unpredictable. This
unpredictability arises because, for a sticky-write firmware
volume, a write may negate a bit in the EFI_FVB_ERASE_POLARITY
state but cannot flip it back again. Before calling the
Write() function, it is recommended for the caller to first call
the EraseBlocks() function to erase the specified block to
write. A block erase cycle will transition bits from the
(NOT)EFI_FVB_ERASE_POLARITY state back to the
EFI_FVB_ERASE_POLARITY state. Implementations should be
mindful that the firmware volume might be in the WriteDisabled
state. If it is in this state, the Write() function must
return the status code EFI_ACCESS_DENIED without modifying the
contents of the firmware volume. The Write() function must
also prevent spanning block boundaries. If a write is
requested that spans a block boundary, the write must store up
to the boundary but not beyond. The output parameter NumBytes
must be set to correctly indicate the number of bytes actually
written. The caller must be aware that a write may be
partially completed. All writes, partial or otherwise, must be
fully flushed to the hardware before the Write() service
returns.
@param This Indicates the EFI_FIRMWARE_VOLUME_BLOCK2_PROTOCOL instance.
@param Lba The starting logical block index to write to.
@param Offset Offset into the block at which to begin writing.
@param NumBytes The pointer to a UINTN.
At entry, *NumBytes contains the total size of the buffer.
At exit, *NumBytes contains the total number of bytes actually written.
@param Buffer The pointer to a caller-allocated buffer that contains the source for the write.
@retval EFI_SUCCESS The firmware volume was written successfully.
@retval EFI_BAD_BUFFER_SIZE The write was attempted across an LBA boundary.
On output, NumBytes contains the total number of bytes
actually written.
@retval EFI_ACCESS_DENIED The firmware volume is in the WriteDisabled state.
@retval EFI_DEVICE_ERROR The block device is malfunctioning and could not be written.
**/
EFI_STATUS
EFIAPI
FvbWrite (
IN CONST EFI_FIRMWARE_VOLUME_BLOCK2_PROTOCOL *This,
IN EFI_LBA Lba,
IN UINTN Offset,
IN OUT UINTN *NumBytes,
IN UINT8 *Buffer
)
{
UINTN BlockSize;
SMMSTORE_INSTANCE *Instance;
Instance = INSTANCE_FROM_FVB_THIS (This);
DEBUG ((DEBUG_BLKIO, "FvbWrite(Parameters: Lba=%ld, Offset=0x%x, *NumBytes=0x%x, Buffer @ 0x%08x)\n", Lba, Offset, *NumBytes, Buffer));
// Cache the block size to avoid de-referencing pointers all the time
BlockSize = Instance->BlockSize;
// The read must not span block boundaries.
// We need to check each variable individually because adding two large values together overflows.
if ((Offset >= BlockSize) ||
(*NumBytes > BlockSize) ||
((Offset + *NumBytes) > BlockSize))
{
DEBUG ((DEBUG_ERROR, "FvbRead: ERROR - EFI_BAD_BUFFER_SIZE: (Offset=0x%x + NumBytes=0x%x) > BlockSize=0x%x\n", Offset, *NumBytes, BlockSize));
return EFI_BAD_BUFFER_SIZE;
}
// We must have some bytes to read
if (*NumBytes == 0) {
return EFI_BAD_BUFFER_SIZE;
}
return SmmStoreLibWrite (Lba, Offset, NumBytes, Buffer);
}
/**
Erases and initialises a firmware volume block.
The EraseBlocks() function erases one or more blocks as denoted
by the variable argument list. The entire parameter list of
blocks must be verified before erasing any blocks. If a block is
requested that does not exist within the associated firmware
volume (it has a larger index than the last block of the
firmware volume), the EraseBlocks() function must return the
status code EFI_INVALID_PARAMETER without modifying the contents
of the firmware volume. Implementations should be mindful that
the firmware volume might be in the WriteDisabled state. If it
is in this state, the EraseBlocks() function must return the
status code EFI_ACCESS_DENIED without modifying the contents of
the firmware volume. All calls to EraseBlocks() must be fully
flushed to the hardware before the EraseBlocks() service
returns.
@param This Indicates the EFI_FIRMWARE_VOLUME_BLOCK2_PROTOCOL
instance.
@param ... The variable argument list is a list of tuples.
Each tuple describes a range of LBAs to erase
and consists of the following:
- An EFI_LBA that indicates the starting LBA
- A UINTN that indicates the number of blocks to erase.
The list is terminated with an EFI_LBA_LIST_TERMINATOR.
For example, the following indicates that two ranges of blocks
(5-7 and 10-11) are to be erased:
EraseBlocks (This, 5, 3, 10, 2, EFI_LBA_LIST_TERMINATOR);
@retval EFI_SUCCESS The erase request successfully completed.
@retval EFI_ACCESS_DENIED The firmware volume is in the WriteDisabled state.
@retval EFI_DEVICE_ERROR The block device is not functioning correctly and could not be written.
The firmware device may have been partially erased.
@retval EFI_INVALID_PARAMETER One or more of the LBAs listed in the variable argument list do
not exist in the firmware volume.
**/
EFI_STATUS
EFIAPI
FvbEraseBlocks (
IN CONST EFI_FIRMWARE_VOLUME_BLOCK2_PROTOCOL *This,
...
)
{
EFI_STATUS Status;
VA_LIST Args;
EFI_LBA StartingLba; // Lba from which we start erasing
UINTN NumOfLba; // Number of Lba blocks to erase
SMMSTORE_INSTANCE *Instance;
Instance = INSTANCE_FROM_FVB_THIS (This);
Status = EFI_SUCCESS;
// Before erasing, check the entire list of parameters to ensure all specified blocks are valid
VA_START (Args, This);
do {
// Get the Lba from which we start erasing
StartingLba = VA_ARG (Args, EFI_LBA);
// Have we reached the end of the list?
if (StartingLba == EFI_LBA_LIST_TERMINATOR) {
// Exit the while loop
break;
}
// How many Lba blocks are we requested to erase?
NumOfLba = VA_ARG (Args, UINTN);
// All blocks must be within range
DEBUG ((
DEBUG_BLKIO,
"FvbEraseBlocks: Check if: ( StartingLba=%ld + NumOfLba=%Lu - 1 ) > LastBlock=%ld.\n",
StartingLba,
(UINT64)NumOfLba,
Instance->LastBlock
));
if ((NumOfLba == 0) || ((StartingLba + NumOfLba - 1) > Instance->LastBlock)) {
VA_END (Args);
DEBUG ((DEBUG_ERROR, "FvbEraseBlocks: ERROR - Lba range goes past the last Lba.\n"));
Status = EFI_INVALID_PARAMETER;
goto EXIT;
}
} while (TRUE);
VA_END (Args);
//
// To get here, all must be ok, so start erasing
//
VA_START (Args, This);
do {
// Get the Lba from which we start erasing
StartingLba = VA_ARG (Args, EFI_LBA);
// Have we reached the end of the list?
if (StartingLba == EFI_LBA_LIST_TERMINATOR) {
// Exit the while loop
break;
}
// How many Lba blocks are we requested to erase?
NumOfLba = VA_ARG (Args, UINTN);
// Go through each one and erase it
while (NumOfLba > 0) {
// Erase it
DEBUG ((DEBUG_BLKIO, "FvbEraseBlocks: Erasing Lba=%ld\n", StartingLba));
Status = SmmStoreLibEraseBlock (StartingLba);
if (EFI_ERROR (Status)) {
VA_END (Args);
Status = EFI_DEVICE_ERROR;
goto EXIT;
}
// Move to the next Lba
StartingLba++;
NumOfLba--;
}
} while (TRUE);
VA_END (Args);
EXIT:
return Status;
}
/**
Initialized the Firmware Volume if necessary and installs the
gEdkiiNvVarStoreFormattedGuid protocol.
@param Instance Pointer to SmmStore instance
**/
EFI_STATUS
EFIAPI
FvbInitialize (
IN SMMSTORE_INSTANCE *Instance
)
{
EFI_STATUS Status;
UINT32 FvbNumLba;
EFI_BOOT_MODE BootMode;
ASSERT ((Instance != NULL));
BootMode = GetBootModeHob ();
if (BootMode == BOOT_WITH_DEFAULT_SETTINGS) {
Status = EFI_INVALID_PARAMETER;
} else {
// Determine if there is a valid header at the beginning of the NorFlash
Status = ValidateFvHeader ();
}
// Install the Default FVB header if required
if (EFI_ERROR (Status)) {
// There is no valid header, so time to install one.
DEBUG ((DEBUG_INFO, "%a: The FVB Header is not valid.\n", __FUNCTION__));
DEBUG ((
DEBUG_INFO,
"%a: Installing a correct one for this volume.\n",
__FUNCTION__
));
// Erase all the NorFlash that is reserved for variable storage
FvbNumLba = (PcdGet32 (PcdFlashNvStorageVariableSize) +
PcdGet32 (PcdFlashNvStorageFtwWorkingSize) +
PcdGet32 (PcdFlashNvStorageFtwSpareSize)) / Instance->BlockSize;
Status = FvbEraseBlocks (&Instance->FvbProtocol, (EFI_LBA)0, FvbNumLba, EFI_LBA_LIST_TERMINATOR);
if (EFI_ERROR (Status)) {
return Status;
}
// Install all appropriate headers
Status = InitializeFvAndVariableStoreHeaders (Instance);
if (EFI_ERROR (Status)) {
return Status;
}
} else {
DEBUG ((DEBUG_INFO, "%a: FVB header is valid\n", __FUNCTION__));
}
//
// The driver implementing the variable read service can now be dispatched;
// the varstore headers are in place.
//
Status = gBS->InstallProtocolInterface (
&gImageHandle,
&gEdkiiNvVarStoreFormattedGuid,
EFI_NATIVE_INTERFACE,
NULL
);
ASSERT_EFI_ERROR (Status);
return Status;
}
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