TxtDxe

Function Table

Address	Name	Description
	TxtDxeLaunchBiosAcm
	DebugPrint
	AssertBreak
	GetPlatformConfigVariable
	SetPlatformConfigVariable
	IsLtProcessor
	IsBiosAcmSuccessful
	IsTxtEnabled
	LocateTxtDeviceMemoryPolicy
	LocateTxtPlatformPolicy
	GetMpTableApicIds
	ConfigureMachineCheckBanks
	GetLtDxeLibSetupOption
	GetAcmErrorType
	HandleAcmError
	ClearLtTpmCmosState
	ApplyTxtPolicyToPlatformConfig
	RegisterForScheckLockConfigCallback
	CloseS3BootScriptResources
	InstallTxtDxeProtocol
	PlatformLaunchBiosAcm
	InitializeLtDxeLib
	DriverInit
	TxtDxeMain
	TxtDxeCleanup
	TxtDxeUnload
	_ModuleEntryPoint
Global	Variables
UEFI	core handles	populated by DriverInit (sub_47C)
EFI_HANDLE	gImageHandle = NULL;
MM	PCI User Access (DxeMmPciBaseLib)
Protocol	and database pointers
VOID	*mPcdProtocol = NULL; // PCD Protocol
HOB	list (DxeHobLib)
Debug	print protocol (gEfiDebugPortProtocolGuid)
SMM	Communication protocol
SMM	Base2 protocol
SMM	LockBox protocol
PI	SMM Communication protocol
TXT	policy data pointers	populated from platform HOBs
TXT_DEVICE_MEMORY_POLICY	*mTxtDeviceMemoryPolicy = NULL; // gEfiPlatformTxtDeviceMemoryGuid
gEfiPlatformTxtPolicyDataGuid	//
AP	/ wake-up state
UINT16	mApCount = 0; // Number of enabled APs (from MP services)
SIPI	vector for AP wake-up
APIC	ID table populated from MP services
ACM	state tracking
BOOLEAN	mBiosAcmCalled = FALSE;
TXT	DXE Protocol instance
TXT_DXE_PROTOCOL	gTxtDxeProtocol;
Forward	declarations of local functions
EFI_STATUS	EFIAPI
Library	helper prototypes that are linked from other compilation units:
Debug	Print and Assert Helpers
Raise	TPL to avoid re-entrancy during protocol lookup
Tpl	= gBootServices->RaiseTPL (TPL_NOTIFY);
Check	CMOS byte 0x4B for the platform debug level.
If	debug level indicates this message should be printed, do so.
UINT8	DebugLevel;
Check	if this error level should be displayed
Filter	= 0;
DEBUG_ERROR	}
UEFI	Library Protocol Locators
CopyMem	wrapper
Validate	that the copy range does not overflow UINTN
if	((Length - 1) > (UINTN)(-1) - (UINTN)Destination) {
Platform	Configuration / UEFI Variable Helpers
LT	(LaGrande Technology / TXT) Feature Checks
Platform	feature MSR
Platform	TXT Policy HOB Access
The	HOB data starts after the GUID extension header
mTxtDeviceMemoryPolicy	*= (TXT_DEVICE_MEMORY_POLICY )((UINT8* )Hob + sizeof (EFI_HOB_GUID_TYPE));**
AP	Wake-up Vector and APIC Setup
Search	for the MP floating pointer structure in the BIOS ROM area
MP	table not found; fall back to allocating a wake-up buffer
at	a fixed address.
No	MP table found; allocate a 0xFFFFF-sized page-aligned buffer
for	the wake-up vector.
EFI_PHYSICAL_ADDRESS	WakeUpBuffer;
MP	table found; configure the wake-up vector from the MP config table
EFI_MP_SERVICES_PROTOCOL	*MpServices;
Use	MP services to get APIC IDs
Set	up the wake-up buffer: write the magic value.
The	WakeUpBuffer address is stored in mApWakeUpVector.
UINT32	*WakeUpBuffer;
Page	number for SIPI
ACM	Launch Support
Save	original MC9-MC11 control values and mask out bit 7 (EN)
Mc9CtlOrig	= (UINT32)AsmReadMsr64 (MSR_IA32_MC9_CTL);
Optionally	save IA32_MCG_CONTAIN if MCG_CMCP (bit 24) is set
if	((AsmReadMsr64 (MSR_IA32_MCG_CAP) & 0x1000000) != 0) {
Write	new values with EN bit cleared
DebugPrint	(DEBUG_INFO, "Ia32_Mc9_Ctl_New = 0x%08x\n", Mc9CtlOrig & ~0x80);
DebugPrint	(DEBUG_INFO, "Write Ia32_Mc9_Ctl_Org = 0x%08x\n", Mc9CtlOrig);
Restore	IA32_MCG_CONTAIN if saved
if	(McgContainValid) {
Step	1: Disable MC9-MC11 machine check banks
ConfigureMachineCheckBanks	(1);
Step	2: If APs exist, send SIPI to start them (required for SINIT)
if	(mApCount > 0) {
Send	INIT IPI to all (including self)
SendInitIpi	();
Step	3: Debug log and raise TPL
DebugPrint	(DEBUG_INFO, "LtDxeLibLaunchBiosAcm: BiosAcmAddress = 0x%08x\n", BiosAcmAddress);
Step	4: Call the platform-specific BIOS ACM launch routine.
This	is a raw assembly routine (sub_4700) that:
The	ACM then executes in a special environment and returns
control	via the LT.SPAD.HIGH register.
DebugPrint	(DEBUG_INFO, "LtDxeLibLaunchBiosAcm: Calling LaunchBiosAcm()\n");
Step	5: Restore TPL and machine check banks
DebugPrint	(DEBUG_INFO, "LtDxeLibLaunchBiosAcm: Restoring TPL\n");
Step	6: Send SIPI to wake APs after ACM
Restore	MC banks to original state
ConfigureMachineCheckBanks	(0);
ACM	Error Handling
LtDxe	lib enable/disable option
ACM	error handling type
Check	if LtDxeLib functions are installed
if	(!GetLtDxeLibSetupOption (&LtDxeLibInstalled) && LtDxeLibInstalled) {
BIOS	setup is configured to ignore ACM errors	just log
if	(GetAcmErrorType (&AcmType)) {
ACM	failure is fatal: clear LT/TPM state and reset
DebugPrint	(DEBUG_ERROR, "Bios Acm Failed. Reboot in non-ltsx mode\n");
Trigger	a system reset via runtime services
Write	"AcmError" variable to record the failure
AcmErrorValue	= 1;
Clear	LT enable bits in SocketProcessorCoreConfig
BufferSize	= sizeof (Buffer);
Variable	storage size
Clear	LT/TPM enable field
Clear	related field
TXT	policy byte in platform config
SMM	/ S3 Boot Script Support
Send	a SMM communication command for Scheck/LockConfig registration
DebugPrint	(DEBUG_INFO, "Register for Scheck/LockConfig Callback\n");
S3	Boot Script Save
Close	Boot Script Table Write if opened
if	(mSmmCommunicationProtocol != NULL) {
if	(mSmmBase2Protocol != NULL) {
Inside	SMM; close SMM communication protocol
if	*(((EFI_SMM_BASE2_PROTOCOL )mSmmBase2Protocol)->Communicate (**
Clear	SMM ready-to-lock flag and close SMM Base2
if	(mSmmReadyToLockEvent != NULL) {
TXT	DXE Protocol Installation
Check	if protocol is already installed
Status	= gBootServices->LocateProtocol (
Set	up the protocol instance
Install	the protocol
Status	= gBootServices->InstallProtocolInterface (
Verify	the protocol was installed correctly by locating it again
Interface	= NULL;
Platform	ACM Launch (Assembly Wrapper)	sub_4700
This	function is implemented in assembly (sub_4700). The equivalent C
logic	is documented here for reference:
UINT64	GdtBackup[2]; // GDT limit + base
UINT64	IdtBackup[2]; // IDT limit + base
UINTN	Cr0, Cr3, Cr4;
if	(Flags != 0) {
Sgdt	(&GdtBackup);
Sidt	(&IdtBackup);
Save	MCG_CAP MTRR state
Cr4	= AsmReadCr4 ();
AsmWriteCr4	**(Cr4	0x4208); // Enable MCE, OSFXSR, OSXMMEXCPT**
Cr0	= AsmReadCr0 ();
AsmWriteCr0	**((Cr0 & 0x9FFFFFDF)	0x40000020); // Set EM, MP; clear NE, TS, EM?**
if	(Flags != 0) Wbinvd ();
else	Invd ();
AsmWriteMsr64	(0x2FF, 0); // Disable MTRRs
Clear	all MTRR pairs
for	(Index = 0; Index < N; Index++) {
AsmWriteMsr64	*(0x200 + Index2, 0); // MTRR_PHYSBASE**
AsmWriteMsr64	*(0x200 + Index2 + 1, 0); // MTRR_PHYSMASK**
Set	up MTRRs for ACM memory range
for	(Remaining = AcmSize; Remaining > 0; ) {
Find	largest power-of-two aligned region
Reg	= MtrrIndex++;
AsmWriteMsr64	*(0x200 + Reg2, AcmBase	6); // WB**
AsmWriteMsr64	*(0x200 + Reg2 + 1, ~(Size-1)	0xF00000800);**
AcmBase	+= Size;
Remaining	-= Size;
AsmWriteMsr64	(0x2FF, 0x800); // Enable MTRRs
AsmWriteMsr64	(0x17B, 0); // Clear MCG_CTL
Zero	all machine check banks
for	(Bank = 0; Bank < McgBankCount; Bank++) {
AsmWriteMsr64	*(0x400 + Bank4 + 1, 0); // MCi_STATUS**
Far	return to ACM entry point
AsmFarReturn	(BiosAcmAddress, 0x08); // Code segment selector
InitializeLtDxeLib	-- sub_DD0
Save	ImageHandle and SystemTable globally (also set in DriverInit)
gImageHandle	= ImageHandle;
Enable	access to CMOS: clear NMI disable bit on port 0x70
IoWrite8	(0x70, IoRead8 (0x530) & 0xBF);
Locate	the SMM Communication protocol for S3 boot script support
Locate	the MP Services protocol for AP management
Check	if TXT is supported on this platform via PCD
Locate	TXT device memory policy from HOB
Status	= LocateTxtDeviceMemoryPolicy ();
Locate	TXT platform policy from HOB
Status	= LocateTxtPlatformPolicy ();
Validate	that the BIOS ACM address is configured
if	(mTxtPlatformPolicy->BiosAcmAddress == 0) {
Get	MP services info: number of processors
Status	= MpServices->GetNumberOfProcessors (MpServices, &mApCount, NULL);
mApCount	includes the BSP; subtract 1 to get AP count
If	there are APs, get their APIC IDs and set up the wake-up vector
Query	each AP for its APIC ID via GetProcessorInfo
ApStatus	= GetMpTableApicIds (&mApCount, ApicIds);
Iterate	and log each APIC ID
for	(Index = 0; Index < mApCount; Index++) {
Entry	Point and Driver Init
Save	protocol pointers
Locate	the DXE Services Table via the protocol database
Status	= SystemTable->BootServices->LocateProtocol (
Locate	the MM PCI User Access protocol (DxeMmPciBaseLib)
if	(mPciUsra == NULL) {
Initialize	HOB list
Get	PCD protocol and enable MTRR for SINIT if not already enabled
Check	if LT (TXT) is supported on this CPU
LtCheck	= IsLtProcessor ();
Delay	loop: read/write timer counter to wait for hardware stabilization
CmosVal	**= IoRead8 (0x70) & 0x80	0x4B; // CMOS offset 0x4B, NMI preserved**
Timer	value
Spin	until delta >= 357
Restore	LT configuration if it was modified during the delay
if	(LtEnabled) {
Final	initialization step (AutoGen.c line 495)
Status	= FinalInitStep ();
Main	Driver Entry Dispatch	original sub_AA8
Step	1: Register for Scheck/LockConfig callback (SMM)
Step	2: Initialize the TXT DXE library (HOBs, protocols, APIC table)
Status	= InitializeLtDxeLib (ImageHandle, SystemTable);
Step	3: Apply TXT policy from HOB to platform configuration
Byte	15 of the HOB data
Step	4: Check if this is an LT-enabled processor
Step	5: LT-enabled processor	proceed with ACM launch
if	(!IsTxtEnabled ()) {
TXT	not enabled, fall through to non-TXT path
Status	= EFI_UNSUPPORTED;
TXT	is enabled	check ACM result
DebugPrint	(DEBUG_INFO, "LT_SPAD_HIGH (0xFED300A4): %r\n"
ACM	completed successfully (or no error)	install protocol
DebugPrint	(DEBUG_ERROR, "Install TXT_DXE_PROTOCOL...\n");
ACM	failed	handle according to BIOS setup policy
HandleAcmError	*((UINT32* )TXT_SPAD_HIGH_REG);**
If	we get here, LT is not enabled or ACM failed
DebugPrint	(DEBUG_ERROR, "Lt not enabled\n");
Attempt	to close S3 boot script resources for a clean state
System	not resetting	close S3 boot script resources
Status	= TxtDxeCleanup ();
Driver	Unload Handler	sub_2FEC / sub_748 equivalent
Module	Entry Point	_ModuleEntryPoint
Step	1: Initialize UEFI core protocols and driver globals
Status	= DriverInit (ImageHandle, SystemTable);
Step	2: Execute TXT-specific initialization
Status	= TxtDxeMain (ImageHandle, SystemTable);
Step	3: If initialization failed, perform cleanup via unload handler
if	(EFI_ERROR (Status)) {

Generated by HR650X BIOS Decompilation Project