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audk/SecurityPkg/VariableAuthenticated/RuntimeDxe/VariableSmmRuntimeDxe.c

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/** @file
Implement all four UEFI Runtime Variable services for the nonvolatile
and volatile storage space and install variable architecture protocol
based on SMM variable module.
Caution: This module requires additional review when modified.
This driver will have external input - variable data.
This external input must be validated carefully to avoid security issue like
buffer overflow, integer overflow.
RuntimeServiceGetVariable() and RuntimeServiceSetVariable() are external API
to receive data buffer. The size should be checked carefully.
InitCommunicateBuffer() is really function to check the variable data size.
Copyright (c) 2010 - 2013, Intel Corporation. All rights reserved.<BR>
This program and the accompanying materials
are licensed and made available under the terms and conditions of the BSD License
which accompanies this distribution. The full text of the license may be found at
http://opensource.org/licenses/bsd-license.php
THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
**/
#include <PiDxe.h>
#include <Protocol/VariableWrite.h>
#include <Protocol/Variable.h>
#include <Protocol/SmmCommunication.h>
#include <Protocol/SmmVariable.h>
#include <Protocol/VariableLock.h>
#include <Library/UefiBootServicesTableLib.h>
#include <Library/UefiRuntimeServicesTableLib.h>
#include <Library/MemoryAllocationLib.h>
#include <Library/UefiDriverEntryPoint.h>
#include <Library/UefiRuntimeLib.h>
#include <Library/BaseMemoryLib.h>
#include <Library/DebugLib.h>
#include <Library/PcdLib.h>
#include <Library/UefiLib.h>
#include <Library/BaseLib.h>
#include <Guid/EventGroup.h>
#include <Guid/AuthenticatedVariableFormat.h>
#include <Guid/SmmVariableCommon.h>
EFI_HANDLE mHandle = NULL;
EFI_SMM_VARIABLE_PROTOCOL *mSmmVariable = NULL;
EFI_EVENT mVirtualAddressChangeEvent = NULL;
EFI_SMM_COMMUNICATION_PROTOCOL *mSmmCommunication = NULL;
UINT8 *mVariableBuffer = NULL;
UINT8 *mVariableBufferPhysical = NULL;
UINTN mVariableBufferSize;
UINTN mVariableBufferPayloadSize;
EFI_LOCK mVariableServicesLock;
EDKII_VARIABLE_LOCK_PROTOCOL mVariableLock;
/**
Acquires lock only at boot time. Simply returns at runtime.
This is a temperary function that will be removed when
EfiAcquireLock() in UefiLib can handle the call in UEFI
Runtimer driver in RT phase.
It calls EfiAcquireLock() at boot time, and simply returns
at runtime.
@param Lock A pointer to the lock to acquire.
**/
VOID
AcquireLockOnlyAtBootTime (
IN EFI_LOCK *Lock
)
{
if (!EfiAtRuntime ()) {
EfiAcquireLock (Lock);
}
}
/**
Releases lock only at boot time. Simply returns at runtime.
This is a temperary function which will be removed when
EfiReleaseLock() in UefiLib can handle the call in UEFI
Runtimer driver in RT phase.
It calls EfiReleaseLock() at boot time and simply returns
at runtime.
@param Lock A pointer to the lock to release.
**/
VOID
ReleaseLockOnlyAtBootTime (
IN EFI_LOCK *Lock
)
{
if (!EfiAtRuntime ()) {
EfiReleaseLock (Lock);
}
}
/**
Initialize the communicate buffer using DataSize and Function.
The communicate size is: SMM_COMMUNICATE_HEADER_SIZE + SMM_VARIABLE_COMMUNICATE_HEADER_SIZE +
DataSize.
Caution: This function may receive untrusted input.
The data size external input, so this function will validate it carefully to avoid buffer overflow.
@param[out] DataPtr Points to the data in the communicate buffer.
@param[in] DataSize The data size to send to SMM.
@param[in] Function The function number to initialize the communicate header.
@retval EFI_INVALID_PARAMETER The data size is too big.
@retval EFI_SUCCESS Find the specified variable.
**/
EFI_STATUS
InitCommunicateBuffer (
OUT VOID **DataPtr OPTIONAL,
IN UINTN DataSize,
IN UINTN Function
)
{
EFI_SMM_COMMUNICATE_HEADER *SmmCommunicateHeader;
SMM_VARIABLE_COMMUNICATE_HEADER *SmmVariableFunctionHeader;
if (DataSize + SMM_COMMUNICATE_HEADER_SIZE + SMM_VARIABLE_COMMUNICATE_HEADER_SIZE > mVariableBufferSize) {
return EFI_INVALID_PARAMETER;
}
SmmCommunicateHeader = (EFI_SMM_COMMUNICATE_HEADER *) mVariableBuffer;
CopyGuid (&SmmCommunicateHeader->HeaderGuid, &gEfiSmmVariableProtocolGuid);
SmmCommunicateHeader->MessageLength = DataSize + SMM_VARIABLE_COMMUNICATE_HEADER_SIZE;
SmmVariableFunctionHeader = (SMM_VARIABLE_COMMUNICATE_HEADER *) SmmCommunicateHeader->Data;
SmmVariableFunctionHeader->Function = Function;
if (DataPtr != NULL) {
*DataPtr = SmmVariableFunctionHeader->Data;
}
return EFI_SUCCESS;
}
/**
Send the data in communicate buffer to SMM.
@param[in] DataSize This size of the function header and the data.
@retval EFI_SUCCESS Success is returned from the functin in SMM.
@retval Others Failure is returned from the function in SMM.
**/
EFI_STATUS
SendCommunicateBuffer (
IN UINTN DataSize
)
{
EFI_STATUS Status;
UINTN CommSize;
EFI_SMM_COMMUNICATE_HEADER *SmmCommunicateHeader;
SMM_VARIABLE_COMMUNICATE_HEADER *SmmVariableFunctionHeader;
CommSize = DataSize + SMM_COMMUNICATE_HEADER_SIZE + SMM_VARIABLE_COMMUNICATE_HEADER_SIZE;
Status = mSmmCommunication->Communicate (mSmmCommunication, mVariableBufferPhysical, &CommSize);
ASSERT_EFI_ERROR (Status);
SmmCommunicateHeader = (EFI_SMM_COMMUNICATE_HEADER *) mVariableBuffer;
SmmVariableFunctionHeader = (SMM_VARIABLE_COMMUNICATE_HEADER *)SmmCommunicateHeader->Data;
return SmmVariableFunctionHeader->ReturnStatus;
}
/**
Mark a variable that will become read-only after leaving the DXE phase of execution.
@param[in] This The VARIABLE_LOCK_PROTOCOL instance.
@param[in] VariableName A pointer to the variable name that will be made read-only subsequently.
@param[in] VendorGuid A pointer to the vendor GUID that will be made read-only subsequently.
@retval EFI_SUCCESS The variable specified by the VariableName and the VendorGuid was marked
as pending to be read-only.
@retval EFI_INVALID_PARAMETER VariableName or VendorGuid is NULL.
Or VariableName is an empty string.
@retval EFI_ACCESS_DENIED EFI_END_OF_DXE_EVENT_GROUP_GUID or EFI_EVENT_GROUP_READY_TO_BOOT has
already been signaled.
@retval EFI_OUT_OF_RESOURCES There is not enough resource to hold the lock request.
**/
EFI_STATUS
EFIAPI
VariableLockRequestToLock (
IN CONST EDKII_VARIABLE_LOCK_PROTOCOL *This,
IN CHAR16 *VariableName,
IN EFI_GUID *VendorGuid
)
{
EFI_STATUS Status;
UINTN VariableNameSize;
UINTN PayloadSize;
SMM_VARIABLE_COMMUNICATE_LOCK_VARIABLE *VariableToLock;
if (VariableName == NULL || VariableName[0] == 0 || VendorGuid == NULL) {
return EFI_INVALID_PARAMETER;
}
VariableNameSize = StrSize (VariableName);
//
// If VariableName exceeds SMM payload limit. Return failure
//
if (VariableNameSize > mVariableBufferPayloadSize - OFFSET_OF (SMM_VARIABLE_COMMUNICATE_LOCK_VARIABLE, Name)) {
return EFI_INVALID_PARAMETER;
}
AcquireLockOnlyAtBootTime(&mVariableServicesLock);
//
// Init the communicate buffer. The buffer data size is:
// SMM_COMMUNICATE_HEADER_SIZE + SMM_VARIABLE_COMMUNICATE_HEADER_SIZE + PayloadSize.
//
PayloadSize = OFFSET_OF (SMM_VARIABLE_COMMUNICATE_LOCK_VARIABLE, Name) + VariableNameSize;
Status = InitCommunicateBuffer ((VOID **) &VariableToLock, PayloadSize, SMM_VARIABLE_FUNCTION_LOCK_VARIABLE);
if (EFI_ERROR (Status)) {
goto Done;
}
ASSERT (VariableToLock != NULL);
CopyGuid (&VariableToLock->Guid, VendorGuid);
VariableToLock->NameSize = VariableNameSize;
CopyMem (VariableToLock->Name, VariableName, VariableToLock->NameSize);
//
// Send data to SMM.
//
Status = SendCommunicateBuffer (PayloadSize);
Done:
ReleaseLockOnlyAtBootTime (&mVariableServicesLock);
return Status;
}
/**
This code finds variable in storage blocks (Volatile or Non-Volatile).
Caution: This function may receive untrusted input.
The data size is external input, so this function will validate it carefully to avoid buffer overflow.
@param[in] VariableName Name of Variable to be found.
@param[in] VendorGuid Variable vendor GUID.
@param[out] Attributes Attribute value of the variable found.
@param[in, out] DataSize Size of Data found. If size is less than the
data, this value contains the required size.
@param[out] Data Data pointer.
@retval EFI_INVALID_PARAMETER Invalid parameter.
@retval EFI_SUCCESS Find the specified variable.
@retval EFI_NOT_FOUND Not found.
@retval EFI_BUFFER_TO_SMALL DataSize is too small for the result.
**/
EFI_STATUS
EFIAPI
RuntimeServiceGetVariable (
IN CHAR16 *VariableName,
IN EFI_GUID *VendorGuid,
OUT UINT32 *Attributes OPTIONAL,
IN OUT UINTN *DataSize,
OUT VOID *Data
)
{
EFI_STATUS Status;
UINTN PayloadSize;
SMM_VARIABLE_COMMUNICATE_ACCESS_VARIABLE *SmmVariableHeader;
UINTN TempDataSize;
UINTN VariableNameSize;
if (VariableName == NULL || VendorGuid == NULL || DataSize == NULL) {
return EFI_INVALID_PARAMETER;
}
if ((*DataSize != 0) && (Data == NULL)) {
return EFI_INVALID_PARAMETER;
}
TempDataSize = *DataSize;
VariableNameSize = StrSize (VariableName);
//
// If VariableName exceeds SMM payload limit. Return failure
//
if (VariableNameSize > mVariableBufferPayloadSize - OFFSET_OF (SMM_VARIABLE_COMMUNICATE_ACCESS_VARIABLE, Name)) {
return EFI_INVALID_PARAMETER;
}
AcquireLockOnlyAtBootTime(&mVariableServicesLock);
//
// Init the communicate buffer. The buffer data size is:
// SMM_COMMUNICATE_HEADER_SIZE + SMM_VARIABLE_COMMUNICATE_HEADER_SIZE + PayloadSize.
//
if (TempDataSize > mVariableBufferPayloadSize - OFFSET_OF (SMM_VARIABLE_COMMUNICATE_ACCESS_VARIABLE, Name) - VariableNameSize) {
//
// If output data buffer exceed SMM payload limit. Trim output buffer to SMM payload size
//
TempDataSize = mVariableBufferPayloadSize - OFFSET_OF (SMM_VARIABLE_COMMUNICATE_ACCESS_VARIABLE, Name) - VariableNameSize;
}
PayloadSize = OFFSET_OF (SMM_VARIABLE_COMMUNICATE_ACCESS_VARIABLE, Name) + VariableNameSize + TempDataSize;
Status = InitCommunicateBuffer ((VOID **)&SmmVariableHeader, PayloadSize, SMM_VARIABLE_FUNCTION_GET_VARIABLE);
if (EFI_ERROR (Status)) {
goto Done;
}
ASSERT (SmmVariableHeader != NULL);
CopyGuid (&SmmVariableHeader->Guid, VendorGuid);
SmmVariableHeader->DataSize = TempDataSize;
SmmVariableHeader->NameSize = VariableNameSize;
if (Attributes == NULL) {
SmmVariableHeader->Attributes = 0;
} else {
SmmVariableHeader->Attributes = *Attributes;
}
CopyMem (SmmVariableHeader->Name, VariableName, SmmVariableHeader->NameSize);
//
// Send data to SMM.
//
Status = SendCommunicateBuffer (PayloadSize);
//
// Get data from SMM.
//
if (Status == EFI_SUCCESS || Status == EFI_BUFFER_TOO_SMALL) {
//
// SMM CommBuffer DataSize can be a trimed value
// Only update DataSize when needed
//
*DataSize = SmmVariableHeader->DataSize;
}
if (Attributes != NULL) {
*Attributes = SmmVariableHeader->Attributes;
}
if (EFI_ERROR (Status)) {
goto Done;
}
CopyMem (Data, (UINT8 *)SmmVariableHeader->Name + SmmVariableHeader->NameSize, SmmVariableHeader->DataSize);
Done:
ReleaseLockOnlyAtBootTime (&mVariableServicesLock);
return Status;
}
/**
This code Finds the Next available variable.
@param[in, out] VariableNameSize Size of the variable name.
@param[in, out] VariableName Pointer to variable name.
@param[in, out] VendorGuid Variable Vendor Guid.
@retval EFI_INVALID_PARAMETER Invalid parameter.
@retval EFI_SUCCESS Find the specified variable.
@retval EFI_NOT_FOUND Not found.
@retval EFI_BUFFER_TO_SMALL DataSize is too small for the result.
**/
EFI_STATUS
EFIAPI
RuntimeServiceGetNextVariableName (
IN OUT UINTN *VariableNameSize,
IN OUT CHAR16 *VariableName,
IN OUT EFI_GUID *VendorGuid
)
{
EFI_STATUS Status;
UINTN PayloadSize;
SMM_VARIABLE_COMMUNICATE_GET_NEXT_VARIABLE_NAME *SmmGetNextVariableName;
UINTN OutVariableNameSize;
UINTN InVariableNameSize;
if (VariableNameSize == NULL || VariableName == NULL || VendorGuid == NULL) {
return EFI_INVALID_PARAMETER;
}
OutVariableNameSize = *VariableNameSize;
InVariableNameSize = StrSize (VariableName);
//
// If input string exceeds SMM payload limit. Return failure
//
if (InVariableNameSize > mVariableBufferPayloadSize - OFFSET_OF (SMM_VARIABLE_COMMUNICATE_GET_NEXT_VARIABLE_NAME, Name)) {
return EFI_INVALID_PARAMETER;
}
AcquireLockOnlyAtBootTime(&mVariableServicesLock);
//
// Init the communicate buffer. The buffer data size is:
// SMM_COMMUNICATE_HEADER_SIZE + SMM_VARIABLE_COMMUNICATE_HEADER_SIZE + PayloadSize.
//
if (OutVariableNameSize > mVariableBufferPayloadSize - OFFSET_OF (SMM_VARIABLE_COMMUNICATE_GET_NEXT_VARIABLE_NAME, Name)) {
//
// If output buffer exceed SMM payload limit. Trim output buffer to SMM payload size
//
OutVariableNameSize = mVariableBufferPayloadSize - OFFSET_OF (SMM_VARIABLE_COMMUNICATE_GET_NEXT_VARIABLE_NAME, Name);
}
//
// Payload should be Guid + NameSize + MAX of Input & Output buffer
//
PayloadSize = OFFSET_OF (SMM_VARIABLE_COMMUNICATE_GET_NEXT_VARIABLE_NAME, Name) + MAX (OutVariableNameSize, InVariableNameSize);
Status = InitCommunicateBuffer ((VOID **)&SmmGetNextVariableName, PayloadSize, SMM_VARIABLE_FUNCTION_GET_NEXT_VARIABLE_NAME);
if (EFI_ERROR (Status)) {
goto Done;
}
ASSERT (SmmGetNextVariableName != NULL);
//
// SMM comm buffer->NameSize is buffer size for return string
//
SmmGetNextVariableName->NameSize = OutVariableNameSize;
CopyGuid (&SmmGetNextVariableName->Guid, VendorGuid);
//
// Copy whole string
//
CopyMem (SmmGetNextVariableName->Name, VariableName, InVariableNameSize);
if (OutVariableNameSize > InVariableNameSize) {
ZeroMem ((UINT8 *) SmmGetNextVariableName->Name + InVariableNameSize, OutVariableNameSize - InVariableNameSize);
}
//
// Send data to SMM
//
Status = SendCommunicateBuffer (PayloadSize);
//
// Get data from SMM.
//
if (Status == EFI_SUCCESS || Status == EFI_BUFFER_TOO_SMALL) {
//
// SMM CommBuffer NameSize can be a trimed value
// Only update VariableNameSize when needed
//
*VariableNameSize = SmmGetNextVariableName->NameSize;
}
if (EFI_ERROR (Status)) {
goto Done;
}
CopyGuid (VendorGuid, &SmmGetNextVariableName->Guid);
CopyMem (VariableName, SmmGetNextVariableName->Name, SmmGetNextVariableName->NameSize);
Done:
ReleaseLockOnlyAtBootTime (&mVariableServicesLock);
return Status;
}
/**
This code sets variable in storage blocks (Volatile or Non-Volatile).
Caution: This function may receive untrusted input.
The data size and data are external input, so this function will validate it carefully to avoid buffer overflow.
@param[in] VariableName Name of Variable to be found.
@param[in] VendorGuid Variable vendor GUID.
@param[in] Attributes Attribute value of the variable found
@param[in] DataSize Size of Data found. If size is less than the
data, this value contains the required size.
@param[in] Data Data pointer.
@retval EFI_INVALID_PARAMETER Invalid parameter.
@retval EFI_SUCCESS Set successfully.
@retval EFI_OUT_OF_RESOURCES Resource not enough to set variable.
@retval EFI_NOT_FOUND Not found.
@retval EFI_WRITE_PROTECTED Variable is read-only.
**/
EFI_STATUS
EFIAPI
RuntimeServiceSetVariable (
IN CHAR16 *VariableName,
IN EFI_GUID *VendorGuid,
IN UINT32 Attributes,
IN UINTN DataSize,
IN VOID *Data
)
{
EFI_STATUS Status;
UINTN PayloadSize;
SMM_VARIABLE_COMMUNICATE_ACCESS_VARIABLE *SmmVariableHeader;
UINTN VariableNameSize;
//
// Check input parameters.
//
if (VariableName == NULL || VariableName[0] == 0 || VendorGuid == NULL) {
return EFI_INVALID_PARAMETER;
}
if (DataSize != 0 && Data == NULL) {
return EFI_INVALID_PARAMETER;
}
VariableNameSize = StrSize (VariableName);
//
// If VariableName or DataSize exceeds SMM payload limit. Return failure
//
if ((VariableNameSize > mVariableBufferPayloadSize - OFFSET_OF (SMM_VARIABLE_COMMUNICATE_ACCESS_VARIABLE, Name)) ||
(DataSize > mVariableBufferPayloadSize - OFFSET_OF (SMM_VARIABLE_COMMUNICATE_ACCESS_VARIABLE, Name) - VariableNameSize)){
return EFI_INVALID_PARAMETER;
}
AcquireLockOnlyAtBootTime(&mVariableServicesLock);
//
// Init the communicate buffer. The buffer data size is:
// SMM_COMMUNICATE_HEADER_SIZE + SMM_VARIABLE_COMMUNICATE_HEADER_SIZE + PayloadSize.
//
PayloadSize = OFFSET_OF (SMM_VARIABLE_COMMUNICATE_ACCESS_VARIABLE, Name) + VariableNameSize + DataSize;
Status = InitCommunicateBuffer ((VOID **)&SmmVariableHeader, PayloadSize, SMM_VARIABLE_FUNCTION_SET_VARIABLE);
if (EFI_ERROR (Status)) {
goto Done;
}
ASSERT (SmmVariableHeader != NULL);
CopyGuid ((EFI_GUID *) &SmmVariableHeader->Guid, VendorGuid);
SmmVariableHeader->DataSize = DataSize;
SmmVariableHeader->NameSize = VariableNameSize;
SmmVariableHeader->Attributes = Attributes;
CopyMem (SmmVariableHeader->Name, VariableName, SmmVariableHeader->NameSize);
CopyMem ((UINT8 *) SmmVariableHeader->Name + SmmVariableHeader->NameSize, Data, DataSize);
//
// Send data to SMM.
//
Status = SendCommunicateBuffer (PayloadSize);
Done:
ReleaseLockOnlyAtBootTime (&mVariableServicesLock);
return Status;
}
/**
This code returns information about the EFI variables.
@param[in] Attributes Attributes bitmask to specify the type of variables
on which to return information.
@param[out] MaximumVariableStorageSize Pointer to the maximum size of the storage space available
for the EFI variables associated with the attributes specified.
@param[out] RemainingVariableStorageSize Pointer to the remaining size of the storage space available
for EFI variables associated with the attributes specified.
@param[out] MaximumVariableSize Pointer to the maximum size of an individual EFI variables
associated with the attributes specified.
@retval EFI_INVALID_PARAMETER An invalid combination of attribute bits was supplied.
@retval EFI_SUCCESS Query successfully.
@retval EFI_UNSUPPORTED The attribute is not supported on this platform.
**/
EFI_STATUS
EFIAPI
RuntimeServiceQueryVariableInfo (
IN UINT32 Attributes,
OUT UINT64 *MaximumVariableStorageSize,
OUT UINT64 *RemainingVariableStorageSize,
OUT UINT64 *MaximumVariableSize
)
{
EFI_STATUS Status;
UINTN PayloadSize;
SMM_VARIABLE_COMMUNICATE_QUERY_VARIABLE_INFO *SmmQueryVariableInfo;
if(MaximumVariableStorageSize == NULL || RemainingVariableStorageSize == NULL || MaximumVariableSize == NULL || Attributes == 0) {
return EFI_INVALID_PARAMETER;
}
AcquireLockOnlyAtBootTime(&mVariableServicesLock);
//
// Init the communicate buffer. The buffer data size is:
// SMM_COMMUNICATE_HEADER_SIZE + SMM_VARIABLE_COMMUNICATE_HEADER_SIZE + PayloadSize;
//
PayloadSize = sizeof (SMM_VARIABLE_COMMUNICATE_QUERY_VARIABLE_INFO);
Status = InitCommunicateBuffer ((VOID **)&SmmQueryVariableInfo, PayloadSize, SMM_VARIABLE_FUNCTION_QUERY_VARIABLE_INFO);
if (EFI_ERROR (Status)) {
goto Done;
}
ASSERT (SmmQueryVariableInfo != NULL);
SmmQueryVariableInfo->Attributes = Attributes;
//
// Send data to SMM.
//
Status = SendCommunicateBuffer (PayloadSize);
if (EFI_ERROR (Status)) {
goto Done;
}
//
// Get data from SMM.
//
*MaximumVariableSize = SmmQueryVariableInfo->MaximumVariableSize;
*MaximumVariableStorageSize = SmmQueryVariableInfo->MaximumVariableStorageSize;
*RemainingVariableStorageSize = SmmQueryVariableInfo->RemainingVariableStorageSize;
Done:
ReleaseLockOnlyAtBootTime (&mVariableServicesLock);
return Status;
}
/**
Exit Boot Services Event notification handler.
Notify SMM variable driver about the event.
@param[in] Event Event whose notification function is being invoked.
@param[in] Context Pointer to the notification function's context.
**/
VOID
EFIAPI
OnExitBootServices (
IN EFI_EVENT Event,
IN VOID *Context
)
{
//
// Init the communicate buffer. The buffer data size is:
// SMM_COMMUNICATE_HEADER_SIZE + SMM_VARIABLE_COMMUNICATE_HEADER_SIZE.
//
InitCommunicateBuffer (NULL, 0, SMM_VARIABLE_FUNCTION_EXIT_BOOT_SERVICE);
//
// Send data to SMM.
//
SendCommunicateBuffer (0);
}
/**
On Ready To Boot Services Event notification handler.
Notify SMM variable driver about the event.
@param[in] Event Event whose notification function is being invoked
@param[in] Context Pointer to the notification function's context
**/
VOID
EFIAPI
OnReadyToBoot (
IN EFI_EVENT Event,
IN VOID *Context
)
{
//
// Init the communicate buffer. The buffer data size is:
// SMM_COMMUNICATE_HEADER_SIZE + SMM_VARIABLE_COMMUNICATE_HEADER_SIZE.
//
InitCommunicateBuffer (NULL, 0, SMM_VARIABLE_FUNCTION_READY_TO_BOOT);
//
// Send data to SMM.
//
SendCommunicateBuffer (0);
}
/**
Notification function of EVT_SIGNAL_VIRTUAL_ADDRESS_CHANGE.
This is a notification function registered on EVT_SIGNAL_VIRTUAL_ADDRESS_CHANGE event.
It convers pointer to new virtual address.
@param[in] Event Event whose notification function is being invoked.
@param[in] Context Pointer to the notification function's context.
**/
VOID
EFIAPI
VariableAddressChangeEvent (
IN EFI_EVENT Event,
IN VOID *Context
)
{
EfiConvertPointer (0x0, (VOID **) &mVariableBuffer);
EfiConvertPointer (0x0, (VOID **) &mSmmCommunication);
}
/**
Initialize variable service and install Variable Architectural protocol.
@param[in] Event Event whose notification function is being invoked.
@param[in] Context Pointer to the notification function's context.
**/
VOID
EFIAPI
SmmVariableReady (
IN EFI_EVENT Event,
IN VOID *Context
)
{
EFI_STATUS Status;
Status = gBS->LocateProtocol (&gEfiSmmVariableProtocolGuid, NULL, (VOID **)&mSmmVariable);
if (EFI_ERROR (Status)) {
return;
}
Status = gBS->LocateProtocol (&gEfiSmmCommunicationProtocolGuid, NULL, (VOID **) &mSmmCommunication);
ASSERT_EFI_ERROR (Status);
//
// Allocate memory for variable communicate buffer.
//
mVariableBufferPayloadSize = MAX (PcdGet32 (PcdMaxVariableSize), PcdGet32 (PcdMaxHardwareErrorVariableSize)) +
OFFSET_OF (SMM_VARIABLE_COMMUNICATE_ACCESS_VARIABLE, Name) - sizeof (VARIABLE_HEADER);
mVariableBufferSize = SMM_COMMUNICATE_HEADER_SIZE + SMM_VARIABLE_COMMUNICATE_HEADER_SIZE + mVariableBufferPayloadSize;
mVariableBuffer = AllocateRuntimePool (mVariableBufferSize);
ASSERT (mVariableBuffer != NULL);
//
// Save the buffer physical address used for SMM conmunication.
//
mVariableBufferPhysical = mVariableBuffer;
gRT->GetVariable = RuntimeServiceGetVariable;
gRT->GetNextVariableName = RuntimeServiceGetNextVariableName;
gRT->SetVariable = RuntimeServiceSetVariable;
gRT->QueryVariableInfo = RuntimeServiceQueryVariableInfo;
//
// Install the Variable Architectural Protocol on a new handle.
//
Status = gBS->InstallProtocolInterface (
&mHandle,
&gEfiVariableArchProtocolGuid,
EFI_NATIVE_INTERFACE,
NULL
);
ASSERT_EFI_ERROR (Status);
}
/**
SMM Non-Volatile variable write service is ready notify event handler.
@param[in] Event Event whose notification function is being invoked.
@param[in] Context Pointer to the notification function's context.
**/
VOID
EFIAPI
SmmVariableWriteReady (
IN EFI_EVENT Event,
IN VOID *Context
)
{
EFI_STATUS Status;
VOID *ProtocolOps;
//
// Check whether the protocol is installed or not.
//
Status = gBS->LocateProtocol (&gSmmVariableWriteGuid, NULL, (VOID **) &ProtocolOps);
if (EFI_ERROR (Status)) {
return;
}
Status = gBS->InstallProtocolInterface (
&mHandle,
&gEfiVariableWriteArchProtocolGuid,
EFI_NATIVE_INTERFACE,
NULL
);
ASSERT_EFI_ERROR (Status);
}
/**
Variable Driver main entry point. The Variable driver places the 4 EFI
runtime services in the EFI System Table and installs arch protocols
for variable read and write services being available. It also registers
a notification function for an EVT_SIGNAL_VIRTUAL_ADDRESS_CHANGE event.
@param[in] ImageHandle The firmware allocated handle for the EFI image.
@param[in] SystemTable A pointer to the EFI System Table.
@retval EFI_SUCCESS Variable service successfully initialized.
**/
EFI_STATUS
EFIAPI
VariableSmmRuntimeInitialize (
IN EFI_HANDLE ImageHandle,
IN EFI_SYSTEM_TABLE *SystemTable
)
{
EFI_STATUS Status;
VOID *SmmVariableRegistration;
VOID *SmmVariableWriteRegistration;
EFI_EVENT OnReadyToBootEvent;
EFI_EVENT ExitBootServiceEvent;
EfiInitializeLock (&mVariableServicesLock, TPL_NOTIFY);
mVariableLock.RequestToLock = VariableLockRequestToLock;
Status = gBS->InstallMultipleProtocolInterfaces (
&mHandle,
&gEdkiiVariableLockProtocolGuid,
&mVariableLock,
NULL
);
ASSERT_EFI_ERROR (Status);
//
// Smm variable service is ready
//
EfiCreateProtocolNotifyEvent (
&gEfiSmmVariableProtocolGuid,
TPL_CALLBACK,
SmmVariableReady,
NULL,
&SmmVariableRegistration
);
//
// Smm Non-Volatile variable write service is ready
//
EfiCreateProtocolNotifyEvent (
&gSmmVariableWriteGuid,
TPL_CALLBACK,
SmmVariableWriteReady,
NULL,
&SmmVariableWriteRegistration
);
//
// Register the event to reclaim variable for OS usage.
//
EfiCreateEventReadyToBootEx (
TPL_NOTIFY,
OnReadyToBoot,
NULL,
&OnReadyToBootEvent
);
//
// Register the event to inform SMM variable that it is at runtime.
//
gBS->CreateEventEx (
EVT_NOTIFY_SIGNAL,
TPL_NOTIFY,
OnExitBootServices,
NULL,
&gEfiEventExitBootServicesGuid,
&ExitBootServiceEvent
);
//
// Register the event to convert the pointer for runtime.
//
gBS->CreateEventEx (
EVT_NOTIFY_SIGNAL,
TPL_NOTIFY,
VariableAddressChangeEvent,
NULL,
&gEfiEventVirtualAddressChangeGuid,
&mVirtualAddressChangeEvent
);
return EFI_SUCCESS;
}
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