TcgPlatformSetupPeiPolicy - Analysis

Module Overview

Property	Value
Module	TcgPlatformSetupPeiPolicy.efi
SHA256	64cbe3c32de56eb053c18852403ae222b05e6d5ef7bca75b61b199ab1a0de990
Arch	32-bit IA32
Base	0xffe17774
Size	0x83a0 (33696 bytes)
IDA Port	13376

Source File

Original source path: e:\hs\AmiModulePkg\TCG2\Common\TcgPlatformSetupPeiPolicy\TcgPlatformSetupPeiPolicy.c

This PEIM installs a TCG Platform Setup Policy PPI to configure TPM-related setup policy during PEI phase.

Function Table

#	Address	Name	Size	Calls	Callers	BBs
1	0xffe179d4	CompareMem	29	0	1	1
2	0xffe179f4	SetMem	21	0	0	1
3	0xffe17a14	CopyMemBackwards	31	1	0	3
4	0xffe17a34	SetMem32	21	0	0	1
5	0xffe17a54	CopyMem	63	1	0	5
6	0xffe17ab4	TcgPlatformSetupPolicyEntry	697	4	0	20
7	0xffe17d6d	CompareMemWithDebug	152	3	1	13
8	0xffe17e05	GetDebugOutputInterface	49	2	4	4
9	0xffe17e36	DebugPrint	42	3	1	4
10	0xffe17e60	DebugOutputString	30	2	2	3
11	0xffe17e7e	GetTpmState	79	1	1	7
12	0xffe17ecd	GetPeiServicesTablePointer	50	3	1	3
13	0xffe17eff	ReadIdtr	35	2	1	3

Function Details

Category: Library Functions

CompareMem (0xffe179d4): 29 bytes
SetMem (0xffe179f4): 21 bytes
CopyMemBackwards (0xffe17a14): 31 bytes
SetMem32 (0xffe17a34): 21 bytes
CopyMem (0xffe17a54): 63 bytes
CompareMemWithDebug (0xffe17d6d): 152 bytes

These are internal implementations of BaseMemoryLib (linked statically).

Category: Debug/Assert Support

CompareMemWithDebug (0xffe17d6d): 152 bytes
GetDebugOutputInterface (0xffe17e05): 49 bytes
DebugPrint (0xffe17e36): 42 bytes
DebugOutputString (0xffe17e60): 30 bytes

These provide ASSERT and debug print support.

Category: PEI Services

GetPeiServicesTablePointer (0xffe17ecd): 50 bytes
ReadIdtr (0xffe17eff): 35 bytes

GetPeiServicesTablePointer reads the IDTR to locate the PEI Services Table. ReadIdtr wraps __sidt().

Category: TPM State

GetTpmState (0xffe17e7e): 79 bytes

GetTpmState reads CMOS register 0x4A via I/O ports 0x70/0x71 to determine TPM state. Returns:

0x0 (EFI_SUCCESS): TPM not present
0x1: EFI_DEVICE_ERROR (TPM disabled)
-1: TPM present but N/A
else: EFI_ACCESS_DENIED

Category: Main Entry Point

TcgPlatformSetupPolicyEntry (0xffe17ab4): 697 bytes (main entry point)

The entry point:

Locates the TCG Platform Setup Policy PPI via PEI Services
Allocates and fills in the policy buffer (GUID table at unk_FFE18304..unk_FFE18310)
Sets up bitfield flags for TPM policy (bits OR'd into v29+47)
Installs the PPI via SystemTable->BootServices->InstallConfigurationTable (offset +24)
Calls ASSERT_EFI_ERROR on failure at source line 213

Call Graph Summary

TcgPlatformSetupPolicyEntry
-- GetDebugOutputInterface
     |-- GetPeiServicesTablePointer
     |     |-- ReadIdtr
-- DebugPrint
     |-- GetDebugOutputInterface
     |-- GetTpmState
-- DebugOutputString
     |-- GetDebugOutputInterface
-- CompareMemWithDebug
-- CompareMem
-- GetDebugOutputInterface

Strings References

e:\hs\AmiModulePkg\TCG2\Common\TcgPlatformSetupPeiPolicy\TcgPlatformSetupPeiPolicy.c (debug path)
!EFI_ERROR (Status) (assert expression at line 213)
\nASSERT_EFI_ERROR (Status = %%r)\n (debug print format)

Notes

All library functions (CompareMem, CopyMem, SetMem, etc.) are statically linked internal implementations
PEI Services Table pointer is obtained via IDT-based method (__sidt)
TPM state detection uses CMOS I/O ports (0x70/0x71) with index 0x4A
The policy PPI contains 4 GUID entries (at +8 through +14) and a flags bitfield (at +47)
bad sp value warning from decompiler due to stack frame manipulation (negative offsets)