Smbios

Function Table

Address	Name	Description
	GetSmbiosStructureSize
	GetSmbiosTotalTableSize
	FindStructureByType
	FindStructureByHandle
	FindStringByNumber
	ReplaceStringInStructure
	ClearSmbiosFieldsByBitmap
	UpdateEPSHeader
	UpdateEPSHeader3
	UpdateSmbiosTableHeader
	UpdateSmbiosTable
	DeleteStructureByHandle
	AddStructureByHandle
	AddStructureByIndex
	ReadStructureByType
	ReadStructureByHandle
	SmbiosEndOfDxe
	SmbiosDynamicUpdate
	UpdateStructuresWithNvramData
	SmbiosPiAddStructure
	SmbiosPiUpdateString
	SmbiosPiRemoveStructure
	SmbiosPiGetNextStructure
	SmbiosDriverEntryPoint
	_ModuleEntryPoint
Global	Data
EFI_SYSTEM_TABLE	*gSystemTable = NULL; // qword_9208
qword_91F8	*EFI_RUNTIME_SERVICES_TABLE gRuntimeServices = NULL; // qword_9200**
qword_9138	- SMBIOS table base
n0x2000	*UINT8 gSmbiosEntryPoint = NULL; // off_8A80 - "SM" EPS**
word_958E	/ n0xFFFD
word_95A0	//
byte_8C1A	(in rdata)
byte_9158	UINT8 gSmbiosFirstDynamicUpdateSeen = TRUE; // byte_8BA8
Protocol	GUIDs (referenced via global data)
EFI_SMBIOS_PROTOCOL	GUID: {0x0358B4B4, 0x4B47, 0x46B7, {0x9C, 0x6C, 0xD4, 0x8F, 0x8A, 0x56, 0x43, 0x55}}
AMI_SMBIOS_PROTOCOL	GUID: {0x8C3D856A, 0x6D47, 0x4C1B, {0xA0, 0x49, 0x3C, 0x59, 0x0B, 0xD7, 0x0C, 0x28}}
extern	EFI_GUID gEfiSmbiosProtocolGuid;
PCD	Protocol handle
VOID	*mPcdProtocol = NULL; // qword_9228
MM	PCI Base Protocol handle
VOID	*mPciUsra = NULL; // qword_9198
SMBIOS	static table FV file GUID
extern	EFI_GUID gSmbiosStaticTableFileGuid; // unk_8920
Debug	helper: macro to call DebugPrint / sub_4F00
sub_4F00	is DebugPrint with error level as first arg
Forward	declarations of static helpers
Start	after the formatted area (the header-defined portion)
StringArea	*= (UINT8 )Record + Record->Length;**
Walk	through the null-terminated strings area
while	*(StringArea != 0) {**
Skip	the terminating null of the last string
Now	StringArea points to the double-null terminator.
Include	the final null.
Add	the terminator structure size
TotalSize	*+= GetSmbiosStructureSize ((SMBIOS_STRUCTURE_HEADER )Cursor);**
Advance	to the Nth string (1-based), walking past null-terminated strings
for	(Index = 1; Index < StringNum; Index++) {
Skip	null terminator
Check	if we are still within the structure
if	((UINTN)StrPos >= (UINTN)EndPos) {
For	now, a placeholder that calls down to the internal implementation.
The	actual decompiled logic (sub_1BEC) performs an in-place string swap
with	compaction of the trailing content.
Full	implementation from decompilation would:
ASSERT	(FALSE); // Not yet fully reimplemented; see sub_1BEC decompilation.
Null	out the specific byte offset (field clearing)
Each	entry is 3 bytes (offset, skip, reserved)
SMBIOS	v2.x EPS update
Calculate	the intermediate checksum value
Set	the SMBIOS table address (lower 32 bits)
Count	the number of SMBIOS structures (excluding the terminator)
Cursor	= gSmbiosTableBase;
Include	the terminator in the count
Compute	the maximum string size across all structures
Fill	EPS fields
Compute	EPS checksum (checksum of bytes 0..length-1 should be 0)
Clear	checksum field first
Bytes	16-30 inclusive
Compute	*the intermediate EPS checksum (for the DMI* area)**
Reset	EPS checksum
Write	the EPS to the legacy region at the pre-allocated address
if	(gSmbiosEntryPoint != NULL) {
SMBIOS	v3.0 EPS update
Set	the table maximum size and address
Compute	EPS checksum (bytes 5..23 sum to zero)
Clear	checksum
Write	the v3 EPS to the pre-allocated region
if	(gSmbiosV3EntryPoint != NULL) {
Update	both EPS headers and re-program to legacy region
If	a legacy region protocol is available, unprotect the E/F segment
Update	v2.x EPS
UpdateEPSHeader	();
Update	v3.0 EPS
DEBUG	((EFI_D_INFO, "::: SMBIOS - Exit UpdateSmbiosTableHeader :::\n"));
Core	SMBIOS table update function
Debug	trace
DEBUG	((EFI_D_INFO, "* SMBIOS - UpdateSmbiosTable *\n"));
If	a LegacyRegionProtocol is available, unprotect
if	(Operation == SMBIOS_DELETE_STRUCTURE) {
Delete	the structure at the given pointer
DEBUG	((EFI_D_INFO, "Deleting structure\n"));
SmbiosCopyMem	*((VOID )Structure, (UINT8* )Structure + StructSize, RemainingSize);**
Fill	vacated space with 0xFF
SmbiosSetMem	*((UINT8 )Structure + RemainingSize, -1, StructSize);**
Unknown	operation
return	EFI_INVALID_PARAMETER;
DEBUG	((EFI_D_INFO, "Adding structure\n"));
Check	if the handle already exists (for inserts requiring uniqueness)
if	(HandleValue <= 0xFFFD) {
Validate	structure integrity
if	*((UINT16* )((UINT8 )Structure + Size - 2) != 0) {*
Handle	special case: Type 4 (Processor) with Length 42 (0x2A)
that	has empty type-specific fields - clip trailing zeros
if	(Structure->Type == SMBIOS_TYPE_PROCESSOR_INFORMATION &&
Compact	away the empty fields at offset 42
SmbiosCopyMem	*((UINT8 )Structure + 42, (UINT8* )Structure + 48, Size - 48);**
Allocate	scratch buffer
ScratchBuffer	= AllocatePool (gSmbiosTableSize + Size);
Copy	existing table into scratch
SmbiosCopyMem	(ScratchBuffer, gSmbiosTableBase, gSmbiosTableSize);
Calculate	current used size
NewTableSize	= GetSmbiosTotalTableSize (gSmbiosTableBase);
Check	if there is enough free space in the table
if	(Size <= gSmbiosTableSize - NewTableSize) {
if	(gSmbiosTableSize - NewTableSize >= Size) {
Enough	space - do in-place operation
Need	to expand the table
if	(!gSmbiosTableExpansionEnabled) {
Cannot	allocate after EndOfDxe
DEBUG	((EFI_D_ERROR
Locate	insertion point
Find	structure by handle to insert before
while	*(WriteCursor != SMBIOS_TERMINATOR_TYPE) {**
Find	insertion point by handle value ordering
while	*(WriteCursor != SMBIOS_TERMINATOR_TYPE &&**
Assign	the handle
if	(HandleValue > 0xFFFD) {
Insert	the new structure
SmbiosCopyMem	(WriteCursor, Structure, Size);
Copy	the remaining structures after the insertion point
Walk	original table from OldCursor to end to compute trail size
while	*(TrailSrc != SMBIOS_TERMINATOR_TYPE) {**
terminator	SmbiosCopyMem (TrailDst, OldCursor, TrailSize);
Check	for handle collision and fix up
if	*(HandleValue >= ((SMBIOS_STRUCTURE_HEADER )CheckCursor)->Handle) {**
Also	update the global next handle tracker
if	(HandleValue >= gNextSmbiosHandle) {
Free	scratch and update EPS
if	(ScratchBuffer != NULL) {
Restore	legacy region protection
DEBUG	((EFI_D_INFO, "Status = %r\n", EFI_SUCCESS));
If	the table was reallocated, free the old one and update the pointer
Delete	a structure by handle
Specialized	path for Processor type structures with specific flags
Status	= EFI_UNSUPPORTED; // Placeholder for sub_26E0 path
Add	a structure by index (insert before given handle)
Specialized	path
Status	= EFI_UNSUPPORTED;
Read	a structure by type
Find	the next available handle
Producer	handle table management
If	the first entry is unused, take it
if	(Entry->Handle == SMBIOS_INVALID_HANDLE) {
Search	for an existing entry with this handle, or an unused slot
for	(Index = 0; Index < SMBIOS_PRODUCER_HANDLE_COUNT; Index++) {
Found	existing entry for this handle (update in place)
Found	an empty slot
Table	full; silently fail (original behavior)
return	NULL;
EndOfDxe	Event Handler
Close	the event (it is a one-shot notification)
Allocate	a scratch buffer to work with the SMBIOS table
ScratchBuffer	= AllocatePool (gSmbiosTableSize);
Locate	LegacyRegionProtocol to unprotect E/F segment for EPS programming
Status	= gBS->LocateProtocol (&gEfiLegacyRegionProtocolGuid, NULL, (VOID )&LegacyRegion);**
Continue	without legacy region programming if protocol unavailable
LegacyRegion	= NULL;
Copy	the SMBIOS table to scratch for processing
Update	both EPS headers and program to legacy region
Lock	the table (no further expansion allowed)
gSmbiosTableExpansionEnabled	= FALSE;
Close	the event
Create	onboard device data (type 41 structures)
Create	onboard device extended info (type 42)
Populate	runtime-configurable structures from NVRAM
Perform	dynamic update of SMBIOS structures (types populated from data sources)
DEBUG	((EFI_D_INFO, "* SMBIOS - DynamicUpdateStructures *\n"));
First	time through: populate from firmware data sources
After	all dynamic updates, trigger memory type information update
Check	if system is in S5/S6 state for memory data decisions
Signal	the new table to listeners
Close	and re-create the periodic event
Update	entry points
Decompiled	logic from sub_B70:
DEBUG	((EFI_D_INFO, "* SMBIOS - UpdateStructuresWithNvramData *\n"));
Placeholder	for the full NVRAM update logic.
The	decompiled function (sub_B70, ~800 instructions) performs:
PI	SMBIOS Protocol implementation
if	*(!FindNextAvailableHandle (0) / check availability* /) {**
Use	the provided handle (replace existing if applicable)
if	*(!AddStructureByHandle (Structure->Handle, (UINT8 )Structure, StructSize)) {**
Locate	the structure by handle
if	*(!FindStructureByHandle (&Cursor, Handle)) {**
Validate	string number
Compute	new string length
NewStringLen	= 0;
ScratchBuffer	= AllocatePool (StructSize + NewStringLen + 1);
Copy	structure to scratch
SmbiosCopyMem	(ScratchBuffer, Cursor, StructSize);
Replace	the string
ReplaceStringInStructure	*(ScratchBuffer, StringNumber, String);**
Delete	old structure
DEBUG	*((EFI_D_INFO, "Deleting structure with handle = %x\n", Handle));**
Add	updated structure
DEBUG	*((EFI_D_INFO, "Adding structure with handle = %x\n", Handle));**
Clean	up
FreePool	(ScratchBuffer);
Remove	from producer handle table (compact entries)
EntryToRemove	= SMBIOS_PRODUCER_HANDLE_COUNT;
Compact	the table
SmbiosCopyMem	(
Clear	the last entry
No	type filter - just advance past current handle
if	*(Handle != SMBIOS_STARTING_HANDLE) {**
Advance	to next
if	*(Cursor == SMBIOS_TERMINATOR_TYPE) {**
Type	filter active
Advance	past current
Find	next matching type
Found	a structure
if	*(Cursor != SMBIOS_TERMINATOR_TYPE) {**
Look	up producer handle
if	(ProducerHandle != NULL) {
Search	producer handle table
if	*(Handle != SMBIOS_TERMINATOR_TYPE) {**
No	more structures
Driver	Entry Point
Initialize	global service pointers
if	(gSystemTable == NULL) {
1	page = 4KB, more than enough for 31 bytes
Initialize	the EPS memory with the "SM" signature
SmbiosCopyMem	(gSmbiosEntryPoint, SMBIOS_ENTRY_POINT_SIG, 31);
Initialize	*the v3 EPS memory with the "SM3" signature*
SmbiosCopyMem	(gSmbiosV3EntryPoint, SMBIOS_V3_ENTRY_POINT_SIG, 24);
Read	"Setup" variable
DataSize	= sizeof (SetupVar);
Read	"SecureBoot" variable
DataSize	= sizeof (BOOLEAN);
Locate	all handles that support FirmwareVolume2 protocol
Search	each FV for the SMBIOS static table file
for	(Index = 0; Index < NumberOfHandles; Index++) {
Read	the raw section from the FV file
Found	the static SMBIOS data section
StaticTableFound	= TRUE;
Skip	section header
Locate	the last handle in the static table and fix up
Update	the terminator handle to the next available
No	static table; start with an empty table (just a terminator)
StaticTableSize	= 0x2000; // Use default table size
Initialize	to 0xFF
SmbiosSetMem	(gSmbiosTableBase, -1, gSmbiosTableSize);
Copy	the static table into the new buffer
SmbiosCopyMem	(gSmbiosTableBase, StaticTableData, StaticTableSize);
Free	the FV section data
DEBUG	((EFI_D_INFO, "Freeing Buffer\n"));
Create	an empty terminator structure
Length	= 4 bytes (Type, Length, Handle[2])
Read	any NVRAM-based structures from Setup variable
Populate	structures from the NVRAM data store
DEBUG	((EFI_D_INFO, "Before UpdateStructuresWithNvramData\n"));
Register	the EndOfDxe event group notification
Status	= gBS->CreateEventEx (
Initialize	the producer handle table to invalid state
Walk	the table and register each existing structure's handle
Update	both EPS headers
the	.data section (off_8A38). This is a reconstructed representation.
SmbiosProtocol	= AllocateZeroPool (sizeof (SMBIOS_PROTOCOL));
Library	constructors (ProcessLibraryConstructorList) are called
in	the AutoGen before reaching the entry function body.
ProcessLibraryConstructorList	(ImageHandle, SystemTable);
Call	the real driver entry point
return	SmbiosDriverEntryPoint (ImageHandle, SystemTable);

Generated by HR650X BIOS Decompilation Project