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/** @file
MmCommunicationNotifyDxe driver creates the notifications of
some protocols and event.
Copyright (c) 2025, Intel Corporation. All rights reserved.<BR>
SPDX-License-Identifier: BSD-2-Clause-Patent
**/
#include "MmCommunicationNotifyDxe.h"
//
// PI 1.7 MM Communication Protocol 2 instance
//
EFI_MM_COMMUNICATION2_PROTOCOL *mMmCommunication2;
MM_COMM_BUFFER mMmCommonBuffer;
EFI_SMM_ACCESS2_PROTOCOL *mSmmAccess;
BOOLEAN mSmmLocked = FALSE;
BOOLEAN mEndOfDxe = FALSE;
//
// Table of Protocol notification and GUIDed Event notifications that the Standalone Mm requires
//
MM_EVENT_NOTIFICATION mMmEvents[] = {
//
// Declare protocol notification on DxeMmReadyToLock protocols. When this notification is established,
// the associated event is immediately signalled, so the notification function will be executed and the
// DXE Mm Ready To Lock Protocol will be found if it is already in the handle database.
//
{ ProtocolNotify, TRUE, &gEfiDxeMmReadyToLockProtocolGuid, MmReadyToLockEventNotify, &gEfiDxeMmReadyToLockProtocolGuid, NULL },
//
// Declare event notification on Ready To Boot Event Group. This is an extra event notification that is
// used to make sure SMRAM is locked before any boot options are processed.
//
{ EventNotify, TRUE, &gEfiEventReadyToBootGuid, MmReadyToLockEventNotify, &gEfiEventReadyToBootGuid, NULL },
//
// Declare event notification on Ready To Boot Event Group. This is used to inform the MM Core
// to notify MM driver that system enter ready to boot.
//
{ EventNotify, FALSE, &gEfiEventReadyToBootGuid, MmGuidedEventNotify, &gEfiEventReadyToBootGuid, NULL },
//
// Declare event notification on EndOfDxe event. When this notification is established,
// the associated event is immediately signalled, so the notification function will be executed and the
// End Of Dxe Protocol will be found if it is already in the handle database.
//
{ EventNotify, TRUE, &gEfiEndOfDxeEventGroupGuid, MmGuidedEventNotify, &gEfiEndOfDxeEventGroupGuid, NULL },
//
// Declare event notification on EndOfDxe event. This is used to set EndOfDxe event signaled flag.
//
{ EventNotify, TRUE, &gEfiEndOfDxeEventGroupGuid, MmEndOfDxeEventNotify, &gEfiEndOfDxeEventGroupGuid, NULL },
//
// Declare event notification on Exit Boot Services Event Group. This is used to inform the MM Core
// to notify MM driver that system enter exit boot services.
//
{ EventNotify, FALSE, &gEfiEventExitBootServicesGuid, MmGuidedEventNotify, &gEfiEventExitBootServicesGuid, NULL },
//
// Terminate the table of event notifications
//
{ EndNotify, FALSE, NULL, NULL, NULL, NULL }
};
/**
Event notification that is fired when GUIDed Event Group is signaled.
@param Event The Event that is being processed, not used.
@param Context Event Context, not used.
**/
VOID
EFIAPI
MmGuidedEventNotify (
IN EFI_EVENT Event,
IN VOID *Context
)
{
UINTN Size;
EFI_MM_COMMUNICATE_HEADER *CommunicateHeader;
CommunicateHeader = (EFI_MM_COMMUNICATE_HEADER *)(UINTN)mMmCommonBuffer.PhysicalStart;
//
// Use Guid to initialize EFI_MM_COMMUNICATE_HEADER structure
//
CopyGuid (&CommunicateHeader->HeaderGuid, (EFI_GUID *)Context);
CommunicateHeader->MessageLength = 1;
CommunicateHeader->Data[0] = 0;
//
// Generate the Software SMI and return the result
//
Size = sizeof (EFI_MM_COMMUNICATE_HEADER);
mMmCommunication2->Communicate (mMmCommunication2, CommunicateHeader, CommunicateHeader, &Size);
}
/**
Event notification that is fired every time a DxeSmmReadyToLock protocol is added
or if gEfiEventReadyToBootGuid is signaled.
@param Event The Event that is being processed, not used.
@param Context Event Context, not used.
**/
VOID
EFIAPI
MmReadyToLockEventNotify (
IN EFI_EVENT Event,
IN VOID *Context
)
{
EFI_STATUS Status;
VOID *Interface;
UINTN Index;
//
// See if we are already locked
//
if (mSmmLocked) {
return;
}
//
// Make sure this notification is for this handler
//
if (CompareGuid ((EFI_GUID *)Context, &gEfiDxeMmReadyToLockProtocolGuid)) {
Status = gBS->LocateProtocol (&gEfiDxeMmReadyToLockProtocolGuid, NULL, &Interface);
if (EFI_ERROR (Status)) {
return;
}
} else {
//
// If MM is not locked yet and we got here from gEfiEventReadyToBootGuid being
// signaled, then gEfiDxeMmReadyToLockProtocolGuid was not installed as expected.
// Print a warning on debug builds.
//
DEBUG ((DEBUG_WARN, "DXE Mm Ready To Lock Protocol not installed before Ready To Boot signal\n"));
}
if (!mEndOfDxe) {
DEBUG ((DEBUG_ERROR, "EndOfDxe Event must be signaled before DxeSmmReadyToLock Protocol installation!\n"));
REPORT_STATUS_CODE (
EFI_ERROR_CODE | EFI_ERROR_UNRECOVERED,
(EFI_SOFTWARE_SMM_DRIVER | EFI_SW_EC_ILLEGAL_SOFTWARE_STATE)
);
ASSERT (FALSE);
}
//
// Lock the SMRAM (Note: Locking SMRAM may not be supported on all platforms)
//
mSmmAccess->Lock (mSmmAccess);
//
// Close protocol and event notification events that do not apply after the
// DXE MM Ready To Lock Protocol has been installed or the Ready To Boot
// event has been signalled.
//
for (Index = 0; mMmEvents[Index].NotifyFunction != NULL; Index++) {
if (mMmEvents[Index].CloseOnLock) {
gBS->CloseEvent (mMmEvents[Index].Event);
}
}
//
// Inform MM Core that the DxeSmmReadyToLock protocol was installed
//
MmGuidedEventNotify (Event, (VOID *)&gEfiDxeMmReadyToLockProtocolGuid);
//
// Print debug message that the SMRAM window is now locked.
//
DEBUG ((DEBUG_INFO, "MmCommunicationNotifyDxe locked SMRAM window\n"));
//
// Set flag so this operation will not be performed again
//
mSmmLocked = TRUE;
}
/**
Event notification that is fired when EndOfDxe Event Group is signaled.
@param Event The Event that is being processed, not used.
@param Context Event Context, not used.
**/
VOID
EFIAPI
MmEndOfDxeEventNotify (
IN EFI_EVENT Event,
IN VOID *Context
)
{
mEndOfDxe = TRUE;
}
/**
The Entry Point for MmCommunicateNotifyDxe driver.
@param ImageHandle The firmware allocated handle for the EFI image.
@param SystemTable A pointer to the EFI System Table.
@retval EFI_SUCCESS The entry point is executed successfully.
@retval Other Some error occurred when executing this entry point.
**/
EFI_STATUS
EFIAPI
MmCommunicationNotifyEntryPoint (
IN EFI_HANDLE ImageHandle,
IN EFI_SYSTEM_TABLE *SystemTable
)
{
EFI_STATUS Status;
EFI_HOB_GUID_TYPE *GuidHob;
MM_COMM_BUFFER *MmCommonBuffer;
UINTN Index;
VOID *Registration;
//
// Locate gMmCommBufferHobGuid and cache the content
//
GuidHob = GetFirstGuidHob (&gMmCommBufferHobGuid);
ASSERT (GuidHob != NULL);
MmCommonBuffer = GET_GUID_HOB_DATA (GuidHob);
CopyMem (&mMmCommonBuffer, MmCommonBuffer, sizeof (MM_COMM_BUFFER));
//
// Get SMM Access Protocol
//
Status = gBS->LocateProtocol (&gEfiSmmAccess2ProtocolGuid, NULL, (VOID **)&mSmmAccess);
ASSERT_EFI_ERROR (Status);
//
// Get MM Communication Protocol 2 instance
//
Status = gBS->LocateProtocol (&gEfiMmCommunication2ProtocolGuid, NULL, (VOID **)&mMmCommunication2);
ASSERT_EFI_ERROR (Status);
//
// Create the set of protocol and event notifications that the Standalone Mm requires
//
for (Index = 0; mMmEvents[Index].NotificationType != EndNotify; Index++) {
if (mMmEvents[Index].NotificationType == ProtocolNotify) {
mMmEvents[Index].Event = EfiCreateProtocolNotifyEvent (
mMmEvents[Index].Guid,
TPL_CALLBACK,
mMmEvents[Index].NotifyFunction,
mMmEvents[Index].NotifyContext,
&Registration
);
} else {
Status = gBS->CreateEventEx (
EVT_NOTIFY_SIGNAL,
TPL_CALLBACK,
mMmEvents[Index].NotifyFunction,
mMmEvents[Index].NotifyContext,
mMmEvents[Index].Guid,
&mMmEvents[Index].Event
);
ASSERT_EFI_ERROR (Status);
}
}
return EFI_SUCCESS;
}
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