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/** @file
SMM STM support functions
Copyright (c) 2015 - 2016, Intel Corporation. All rights reserved.<BR>
SPDX-License-Identifier: BSD-2-Clause-Patent
**/
#include <PiMm.h>
#include <Library/DebugLib.h>
#include "SmmStm.h"
///
/// Page Table Entry
///
#define IA32_PG_P BIT0
#define IA32_PG_RW BIT1
#define IA32_PG_PS BIT7
/**
Create 4G page table for STM.
4M Non-PAE page table in IA32 version.
@param PageTableBase The page table base in MSEG
**/
VOID
StmGen4GPageTable (
IN UINTN PageTableBase
)
{
UINTN Index;
UINT32 *Pte;
UINT32 Address;
Pte = (UINT32*)(UINTN)PageTableBase;
Address = 0;
for (Index = 0; Index < SIZE_4KB / sizeof (*Pte); Index++) {
*Pte = Address | IA32_PG_PS | IA32_PG_RW | IA32_PG_P;
Pte++;
Address += SIZE_4MB;
}
}
/**
This is SMM exception handle.
Consumed by STM when exception happen.
@param Context STM protection exception stack frame
@return the EBX value for STM reference.
EBX = 0: resume SMM guest using register state found on exception stack.
EBX = 1 to 0x0F: EBX contains a BIOS error code which the STM must record in the
TXT.ERRORCODE register and subsequently reset the system via
TXT.CMD.SYS_RESET. The value of the TXT.ERRORCODE register is calculated as
follows: TXT.ERRORCODE = (EBX & 0x0F) | STM_CRASH_BIOS_PANIC
EBX = 0x10 to 0xFFFFFFFF - reserved, do not use.
**/
UINT32
EFIAPI
SmmStmExceptionHandler (
IN OUT STM_PROTECTION_EXCEPTION_STACK_FRAME Context
)
{
// TBD - SmmStmExceptionHandler, record information
DEBUG ((DEBUG_ERROR, "SmmStmExceptionHandler ...\n"));
//
// Skip this instruction and continue;
//
Context.Ia32StackFrame->Rip += Context.Ia32StackFrame->VmcsExitInstructionLength;
return 0;
}
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