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Use on-demand paging for CpuSaveStates read/write. It was measured about 200us for either read or write the PI CpuSaveStates to framework, ~400us in total on a platform with 80 CPUs with original for loop implementation. So with on-demand paging, if the framework SMI handler doesn’t read/write CpuSaveStates, ~400us will be saved. If the handler happens to use CpuSaveStates, there will be about 20us overhead for either read or write a page which contains 5 continuous CpuSaveStates. 

git-svn-id: https://edk2.svn.sourceforge.net/svnroot/edk2/trunk/edk2@10328 6f19259b-4bc3-4df7-8a09-765794883524
This commit is contained in:
jgong5 2010-04-02 01:39:19 +00:00
parent 553472f644
commit ff443d3ebd
5 changed files with 475 additions and 41 deletions
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20
EdkCompatibilityPkg/Compatibility/SmmBaseHelper/PageFaultHandler.c Normal file
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@ -0,0 +1,20 @@
/** @file
Page fault handler that does nothing.
Copyright (c) 2010, Intel Corporation
All rights reserved. This program and the accompanying materials
are licensed and made available under the terms and conditions of the BSD License
which accompanies this distribution. The full text of the license may be found at
http://opensource.org/licenses/bsd-license.php
THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
**/
VOID
PageFaultHandlerHook (
VOID
)
{
}

382
EdkCompatibilityPkg/Compatibility/SmmBaseHelper/SmmBaseHelper.c
View File

@ -25,6 +25,8 @@
#include <Library/DevicePathLib.h>
#include <Library/CacheMaintenanceLib.h>
#include <Library/MemoryAllocationLib.h>
#include <Library/SynchronizationLib.h>
#include <Library/CpuLib.h>
#include <Guid/SmmBaseThunkCommunication.h>
#include <Protocol/SmmBaseHelperReady.h>
#include <Protocol/SmmCpu.h>
@ -69,6 +71,13 @@ EFI_SMM_BASE_HELPER_READY_PROTOCOL *mSmmBaseHelperReady;
EFI_SMM_SYSTEM_TABLE *mFrameworkSmst;
UINTN mNumberOfProcessors;
BOOLEAN mLocked = FALSE;
BOOLEAN mPageTableHookEnabled;
BOOLEAN mHookInitialized;
UINT64 *mCpuStatePageTable;
SPIN_LOCK mPFLock;
UINT64 mPhyMask;
VOID *mOriginalHandler;
EFI_SMM_CPU_SAVE_STATE *mShadowSaveState;
LIST_ENTRY mCallbackInfoListHead = INITIALIZE_LIST_HEAD_VARIABLE (mCallbackInfoListHead);
@ -97,6 +106,271 @@ CPU_SAVE_STATE_CONVERSION mCpuSaveStateConvTable[] = {
{EFI_SMM_SAVE_STATE_REGISTER_CR3 , CPU_SAVE_STATE_GET_OFFSET(CR3)}
};
VOID
PageFaultHandlerHook (
VOID
);
VOID
ReadCpuSaveState (
UINTN CpuIndex,
EFI_SMM_CPU_SAVE_STATE *ToRead
)
{
EFI_STATUS Status;
UINTN Index;
EFI_SMM_CPU_STATE *State;
EFI_SMI_CPU_SAVE_STATE *SaveState;
State = (EFI_SMM_CPU_STATE *)gSmst->CpuSaveState[CpuIndex];
if (ToRead != NULL) {
SaveState = &ToRead->Ia32SaveState;
} else {
SaveState = &mFrameworkSmst->CpuSaveState[CpuIndex].Ia32SaveState;
}
if (State->x86.SMMRevId < EFI_SMM_MIN_REV_ID_x64) {
SaveState->SMBASE = State->x86.SMBASE;
SaveState->SMMRevId = State->x86.SMMRevId;
SaveState->IORestart = State->x86.IORestart;
SaveState->AutoHALTRestart = State->x86.AutoHALTRestart;
} else {
SaveState->SMBASE = State->x64.SMBASE;
SaveState->SMMRevId = State->x64.SMMRevId;
SaveState->IORestart = State->x64.IORestart;
SaveState->AutoHALTRestart = State->x64.AutoHALTRestart;
}
for (Index = 0; Index < sizeof (mCpuSaveStateConvTable) / sizeof (CPU_SAVE_STATE_CONVERSION); Index++) {
///
/// Try to use SMM CPU Protocol to access CPU save states if possible
///
Status = mSmmCpu->ReadSaveState (
mSmmCpu,
(UINTN)sizeof (UINT32),
mCpuSaveStateConvTable[Index].Register,
CpuIndex,
((UINT8 *)SaveState) + mCpuSaveStateConvTable[Index].Offset
);
ASSERT_EFI_ERROR (Status);
}
}
VOID
WriteCpuSaveState (
UINTN CpuIndex,
EFI_SMM_CPU_SAVE_STATE *ToWrite
)
{
EFI_STATUS Status;
UINTN Index;
EFI_SMI_CPU_SAVE_STATE *SaveState;
if (ToWrite != NULL) {
SaveState = &ToWrite->Ia32SaveState;
} else {
SaveState = &mFrameworkSmst->CpuSaveState[CpuIndex].Ia32SaveState;
}
for (Index = 0; Index < sizeof (mCpuSaveStateConvTable) / sizeof (CPU_SAVE_STATE_CONVERSION); Index++) {
Status = mSmmCpu->WriteSaveState (
mSmmCpu,
(UINTN)sizeof (UINT32),
mCpuSaveStateConvTable[Index].Register,
CpuIndex,
((UINT8 *)SaveState) +
mCpuSaveStateConvTable[Index].Offset
);
}
}
VOID
ReadWriteCpuStatePage (
UINT64 PageAddress,
BOOLEAN IsRead
)
{
UINTN FirstSSIndex; // Index of first CpuSaveState in the page
UINTN LastSSIndex; // Index of last CpuSaveState in the page
BOOLEAN FirstSSAligned; // Whether first CpuSaveState is page-aligned
BOOLEAN LastSSAligned; // Whether the end of last CpuSaveState is page-aligned
UINTN ClippedSize;
UINTN CpuIndex;
FirstSSIndex = ((UINTN)PageAddress - (UINTN)mFrameworkSmst->CpuSaveState) / sizeof (EFI_SMM_CPU_SAVE_STATE);
FirstSSAligned = TRUE;
if (((UINTN)PageAddress - (UINTN)mFrameworkSmst->CpuSaveState) % sizeof (EFI_SMM_CPU_SAVE_STATE) != 0) {
FirstSSIndex++;
FirstSSAligned = FALSE;
}
LastSSIndex = ((UINTN)PageAddress + SIZE_4KB - (UINTN)mFrameworkSmst->CpuSaveState - 1) / sizeof (EFI_SMM_CPU_SAVE_STATE);
LastSSAligned = TRUE;
if (((UINTN)PageAddress + SIZE_4KB - (UINTN)mFrameworkSmst->CpuSaveState) % sizeof (EFI_SMM_CPU_SAVE_STATE) != 0) {
LastSSIndex--;
LastSSAligned = FALSE;
}
for (CpuIndex = FirstSSIndex; CpuIndex <= LastSSIndex && CpuIndex < mNumberOfProcessors; CpuIndex++) {
if (IsRead) {
ReadCpuSaveState (CpuIndex, NULL);
} else {
WriteCpuSaveState (CpuIndex, NULL);
}
}
if (!FirstSSAligned) {
ReadCpuSaveState (FirstSSIndex - 1, mShadowSaveState);
ClippedSize = (UINTN)&mFrameworkSmst->CpuSaveState[FirstSSIndex] & (SIZE_4KB - 1);
if (IsRead) {
CopyMem ((VOID*)(UINTN)PageAddress, (VOID*)((UINTN)(mShadowSaveState + 1) - ClippedSize), ClippedSize);
} else {
CopyMem ((VOID*)((UINTN)(mShadowSaveState + 1) - ClippedSize), (VOID*)(UINTN)PageAddress, ClippedSize);
WriteCpuSaveState (FirstSSIndex - 1, mShadowSaveState);
}
}
if (!LastSSAligned && LastSSIndex + 1 < mNumberOfProcessors) {
ReadCpuSaveState (LastSSIndex + 1, mShadowSaveState);
ClippedSize = SIZE_4KB - ((UINTN)&mFrameworkSmst->CpuSaveState[LastSSIndex + 1] & (SIZE_4KB - 1));
if (IsRead) {
CopyMem (&mFrameworkSmst->CpuSaveState[LastSSIndex + 1], mShadowSaveState, ClippedSize);
} else {
CopyMem (mShadowSaveState, &mFrameworkSmst->CpuSaveState[LastSSIndex + 1], ClippedSize);
WriteCpuSaveState (LastSSIndex + 1, mShadowSaveState);
}
}
}
BOOLEAN
PageFaultHandler (
VOID
)
{
BOOLEAN IsHandled;
UINT64 *PageTable;
UINT64 PFAddress;
UINTN NumCpuStatePages;
ASSERT (mPageTableHookEnabled);
AcquireSpinLock (&mPFLock);
PageTable = (UINT64*)(UINTN)(AsmReadCr3 () & mPhyMask);
PFAddress = AsmReadCr2 ();
NumCpuStatePages = EFI_SIZE_TO_PAGES (mNumberOfProcessors * sizeof (EFI_SMM_CPU_SAVE_STATE));
IsHandled = FALSE;
if (((UINTN)mFrameworkSmst->CpuSaveState & ~(SIZE_2MB-1)) == (PFAddress & ~(SIZE_2MB-1))) {
if ((UINTN)mFrameworkSmst->CpuSaveState <= PFAddress &&
PFAddress < (UINTN)mFrameworkSmst->CpuSaveState + EFI_PAGES_TO_SIZE (NumCpuStatePages)
) {
mCpuStatePageTable[BitFieldRead64 (PFAddress, 12, 20)] |= BIT0 | BIT1; // present and rw
CpuFlushTlb ();
ReadWriteCpuStatePage (PFAddress & ~(SIZE_4KB-1), TRUE);
IsHandled = TRUE;
} else {
ASSERT (FALSE);
}
}
ReleaseSpinLock (&mPFLock);
return IsHandled;
}
VOID
WriteBackDirtyPages (
VOID
)
{
UINTN NumCpuStatePages;
UINTN PTIndex;
UINTN PTStartIndex;
UINTN PTEndIndex;
NumCpuStatePages = EFI_SIZE_TO_PAGES (mNumberOfProcessors * sizeof (EFI_SMM_CPU_SAVE_STATE));
PTStartIndex = (UINTN)BitFieldRead64 ((UINT64)mFrameworkSmst->CpuSaveState, 12, 20);
PTEndIndex = (UINTN)BitFieldRead64 ((UINT64)mFrameworkSmst->CpuSaveState + EFI_PAGES_TO_SIZE(NumCpuStatePages) - 1, 12, 20);
for (PTIndex = PTStartIndex; PTIndex <= PTEndIndex; PTIndex++) {
if ((mCpuStatePageTable[PTIndex] & (BIT0|BIT6)) == (BIT0|BIT6)) { // present and dirty?
ReadWriteCpuStatePage (mCpuStatePageTable[PTIndex] & mPhyMask, FALSE);
}
}
}
VOID
HookPageFaultHandler (
VOID
)
{
IA32_DESCRIPTOR Idtr;
IA32_IDT_GATE_DESCRIPTOR *IdtGateDesc;
UINT32 OffsetUpper;
InitializeSpinLock (&mPFLock);
AsmReadIdtr (&Idtr);
IdtGateDesc = (IA32_IDT_GATE_DESCRIPTOR *) Idtr.Base;
OffsetUpper = *(UINT32*)((UINT64*)IdtGateDesc + 1);
mOriginalHandler = (VOID *)(UINTN)(LShiftU64 (OffsetUpper, 32) + IdtGateDesc[14].Bits.OffsetLow + (IdtGateDesc[14].Bits.OffsetHigh << 16));
IdtGateDesc[14].Bits.OffsetLow = (UINT32)((UINTN)PageFaultHandlerHook & ((1 << 16) - 1));
IdtGateDesc[14].Bits.OffsetHigh = (UINT32)(((UINTN)PageFaultHandlerHook >> 16) & ((1 << 16) - 1));
}
UINT64 *
InitCpuStatePageTable (
VOID *HookData
)
{
UINTN Index;
UINT64 *PageTable;
UINT64 *PDPTE;
UINT64 HookAddress;
UINT64 PDE;
UINT64 Address;
//
// Initialize physical address mask
// NOTE: Physical memory above virtual address limit is not supported !!!
//
AsmCpuid (0x80000008, (UINT32*)&Index, NULL, NULL, NULL);
mPhyMask = LShiftU64 (1, (UINT8)Index) - 1;
mPhyMask &= (1ull << 48) - EFI_PAGE_SIZE;
HookAddress = (UINT64)(UINTN)HookData;
PageTable = (UINT64 *)(UINTN)(AsmReadCr3 () & mPhyMask);
PageTable = (UINT64 *)(UINTN)(PageTable[BitFieldRead64 (HookAddress, 39, 47)] & mPhyMask);
PageTable = (UINT64 *)(UINTN)(PageTable[BitFieldRead64 (HookAddress, 30, 38)] & mPhyMask);
PDPTE = (UINT64 *)(UINTN)PageTable;
PDE = PDPTE[BitFieldRead64 (HookAddress, 21, 29)];
ASSERT ((PDE & BIT0) != 0); // Present and 2M Page
if ((PDE & BIT7) == 0) { // 4KB Page Directory
PageTable = (UINT64 *)(UINTN)(PDE & mPhyMask);
} else {
ASSERT ((PDE & mPhyMask) == (HookAddress & ~(SIZE_2MB-1))); // 2MB Page Point to HookAddress
PageTable = AllocatePages (1);
Address = HookAddress & ~(SIZE_2MB-1);
for (Index = 0; Index < 512; Index++) {
PageTable[Index] = Address | BIT0 | BIT1; // Present and RW
Address += SIZE_4KB;
}
PDPTE[BitFieldRead64 (HookAddress, 21, 29)] = (UINT64)(UINTN)PageTable | BIT0 | BIT1; // Present and RW
}
return PageTable;
}
VOID
HookCpuStateMemory (
EFI_SMM_CPU_SAVE_STATE *CpuSaveState
)
{
UINT64 Index;
UINT64 PTStartIndex;
UINT64 PTEndIndex;
PTStartIndex = BitFieldRead64 ((UINTN)CpuSaveState, 12, 20);
PTEndIndex = BitFieldRead64 ((UINTN)CpuSaveState + mNumberOfProcessors * sizeof (EFI_SMM_CPU_SAVE_STATE) - 1, 12, 20);
for (Index = PTStartIndex; Index <= PTEndIndex; Index++) {
mCpuStatePageTable[Index] &= ~(BIT0|BIT5|BIT6); // not present nor accessed nor dirty
}
}
/**
Framework SMST SmmInstallConfigurationTable() Thunk.
@ -133,6 +407,62 @@ SmmInstallConfigurationTable (
return Status;
}
VOID
InitHook (
EFI_SMM_SYSTEM_TABLE *FrameworkSmst
)
{
UINTN NumCpuStatePages;
UINTN CpuStatePage;
UINTN Bottom2MPage;
UINTN Top2MPage;
mPageTableHookEnabled = FALSE;
NumCpuStatePages = EFI_SIZE_TO_PAGES (mNumberOfProcessors * sizeof (EFI_SMM_CPU_SAVE_STATE));
//
// Only hook page table for X64 image and less than 2MB needed to hold all CPU Save States
//
if (EFI_IMAGE_MACHINE_TYPE_SUPPORTED(EFI_IMAGE_MACHINE_X64) && NumCpuStatePages <= EFI_SIZE_TO_PAGES (SIZE_2MB)) {
//
// Allocate double page size to make sure all CPU Save States are in one 2MB page.
//
CpuStatePage = (UINTN)AllocatePages (NumCpuStatePages * 2);
ASSERT (CpuStatePage != 0);
Bottom2MPage = CpuStatePage & ~(SIZE_2MB-1);
Top2MPage = (CpuStatePage + EFI_PAGES_TO_SIZE (NumCpuStatePages * 2) - 1) & ~(SIZE_2MB-1);
if (Bottom2MPage == Top2MPage ||
CpuStatePage + EFI_PAGES_TO_SIZE (NumCpuStatePages * 2) - Top2MPage >= EFI_PAGES_TO_SIZE (NumCpuStatePages)
) {
//
// If the allocated 4KB pages are within the same 2MB page or higher portion is larger, use higher portion pages.
//
FrameworkSmst->CpuSaveState = (EFI_SMM_CPU_SAVE_STATE *)(CpuStatePage + EFI_PAGES_TO_SIZE (NumCpuStatePages));
FreePages ((VOID*)CpuStatePage, NumCpuStatePages);
} else {
FrameworkSmst->CpuSaveState = (EFI_SMM_CPU_SAVE_STATE *)CpuStatePage;
FreePages ((VOID*)(CpuStatePage + EFI_PAGES_TO_SIZE (NumCpuStatePages)), NumCpuStatePages);
}
//
// Add temporary working buffer for hooking
//
mShadowSaveState = (EFI_SMM_CPU_SAVE_STATE*) AllocatePool (sizeof (EFI_SMM_CPU_SAVE_STATE));
ASSERT (mShadowSaveState != NULL);
//
// Allocate and initialize 4KB Page Table for hooking CpuSaveState.
// Replace the original 2MB PDE with new 4KB page table.
//
mCpuStatePageTable = InitCpuStatePageTable (FrameworkSmst->CpuSaveState);
//
// Mark PTE for CpuSaveState as non-exist.
//
HookCpuStateMemory (FrameworkSmst->CpuSaveState);
HookPageFaultHandler ();
CpuFlushTlb ();
mPageTableHookEnabled = TRUE;
}
mHookInitialized = TRUE;
}
/**
Construct a Framework SMST based on the PI SMM SMST.
@ -164,6 +494,7 @@ ConstructFrameworkSmst (
FrameworkSmst->Hdr.Revision = EFI_SMM_SYSTEM_TABLE_REVISION;
CopyGuid (&FrameworkSmst->EfiSmmCpuIoGuid, &mEfiSmmCpuIoGuid);
mHookInitialized = FALSE;
FrameworkSmst->CpuSaveState = (EFI_SMM_CPU_SAVE_STATE *)AllocateZeroPool (mNumberOfProcessors * sizeof (EFI_SMM_CPU_SAVE_STATE));
ASSERT (FrameworkSmst->CpuSaveState != NULL);
@ -360,44 +691,22 @@ CallbackThunk (
{
EFI_STATUS Status;
CALLBACK_INFO *CallbackInfo;
UINTN Index;
UINTN CpuIndex;
EFI_SMM_CPU_STATE *State;
EFI_SMI_CPU_SAVE_STATE *SaveState;
///
/// Before transferring the control into the Framework SMI handler, update CPU Save States
/// and MP states in the Framework SMST.
///
for (CpuIndex = 0; CpuIndex < mNumberOfProcessors; CpuIndex++) {
State = (EFI_SMM_CPU_STATE *)gSmst->CpuSaveState[CpuIndex];
SaveState = &mFrameworkSmst->CpuSaveState[CpuIndex].Ia32SaveState;
if (State->x86.SMMRevId < EFI_SMM_MIN_REV_ID_x64) {
SaveState->SMBASE = State->x86.SMBASE;
SaveState->SMMRevId = State->x86.SMMRevId;
SaveState->IORestart = State->x86.IORestart;
SaveState->AutoHALTRestart = State->x86.AutoHALTRestart;
} else {
SaveState->SMBASE = State->x64.SMBASE;
SaveState->SMMRevId = State->x64.SMMRevId;
SaveState->IORestart = State->x64.IORestart;
SaveState->AutoHALTRestart = State->x64.AutoHALTRestart;
if (!mHookInitialized) {
InitHook (mFrameworkSmst);
}
for (Index = 0; Index < sizeof (mCpuSaveStateConvTable) / sizeof (CPU_SAVE_STATE_CONVERSION); Index++) {
///
/// Try to use SMM CPU Protocol to access CPU save states if possible
///
Status = mSmmCpu->ReadSaveState (
mSmmCpu,
(UINTN)sizeof (UINT32),
mCpuSaveStateConvTable[Index].Register,
CpuIndex,
((UINT8 *)SaveState) + mCpuSaveStateConvTable[Index].Offset
);
ASSERT_EFI_ERROR (Status);
if (mPageTableHookEnabled) {
HookCpuStateMemory (mFrameworkSmst->CpuSaveState);
CpuFlushTlb ();
} else {
for (CpuIndex = 0; CpuIndex < mNumberOfProcessors; CpuIndex++) {
ReadCpuSaveState (CpuIndex, NULL);
}
}
@ -422,16 +731,11 @@ CallbackThunk (
///
/// Save CPU Save States in case any of them was modified
///
if (mPageTableHookEnabled) {
WriteBackDirtyPages ();
} else {
for (CpuIndex = 0; CpuIndex < mNumberOfProcessors; CpuIndex++) {
for (Index = 0; Index < sizeof (mCpuSaveStateConvTable) / sizeof (CPU_SAVE_STATE_CONVERSION); Index++) {
Status = mSmmCpu->WriteSaveState (
mSmmCpu,
(UINTN)sizeof (UINT32),
mCpuSaveStateConvTable[Index].Register,
CpuIndex,
((UINT8 *)&mFrameworkSmst->CpuSaveState[CpuIndex].Ia32SaveState) +
mCpuSaveStateConvTable[Index].Offset
);
WriteCpuSaveState (CpuIndex, NULL);
}
}

12
EdkCompatibilityPkg/Compatibility/SmmBaseHelper/SmmBaseHelper.inf
View File

@ -31,6 +31,16 @@
[Sources]
SmmBaseHelper.c
[Sources.Ia32]
PageFaultHandler.c
[Sources.X64]
X64/PageFaultHandler.asm | MSFT
X64/PageFaultHandler.asm | INTEL
X64/PageFaultHandler.S | GCC
[Packages]
MdePkg/MdePkg.dec
MdeModulePkg/MdeModulePkg.dec
@ -46,6 +56,8 @@
DevicePathLib
CacheMaintenanceLib
MemoryAllocationLib
SynchronizationLib
CpuLib
[Guids]
gEfiSmmBaseThunkCommunicationGuid

46
EdkCompatibilityPkg/Compatibility/SmmBaseHelper/X64/PageFaultHandler.S Normal file
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@ -0,0 +1,46 @@
#------------------------------------------------------------------------------
#
# Copyright (c) 2006 - 2010, Intel Corporation
# All rights reserved. This program and the accompanying materials
# are licensed and made available under the terms and conditions of the BSD License
# which accompanies this distribution. The full text of the license may be found at
# http://opensource.org/licenses/bsd-license.php
#
# THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
# WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
#
# Module Name:
#
# PageFaultHandler.S
#
# Abstract:
#
# Defines page fault handler used to hook SMM IDT
#
#------------------------------------------------------------------------------
ASM_GLOBAL ASM_PFX(PageFaultHandlerHook)
ASM_PFX(PageFaultHandlerHook):
pushq %rax # save all volatile registers
pushq %rcx
pushq %rdx
pushq %r8
pushq %r9
pushq %r10
pushq %r11
addq $-0x20, %rsp
call ASM_PFX(PageFaultHandler)
addq $0x20, %rsp
test %rax, %rax
popq %r11
popq %r10
popq %r9
popq %r8
popq %rdx
popq %rcx
popq %rax # restore all volatile registers
jnz L1
jmp ASM_PFX(mOriginalHandler)
L1:
addq $0x08, %rsp # skip error code for PF
iretq

52
EdkCompatibilityPkg/Compatibility/SmmBaseHelper/X64/PageFaultHandler.asm Normal file
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@ -0,0 +1,52 @@
;------------------------------------------------------------------------------
;
; Copyright (c) 2010, Intel Corporation
; All rights reserved. This program and the accompanying materials
; are licensed and made available under the terms and conditions of the BSD License
; which accompanies this distribution. The full text of the license may be found at
; http://opensource.org/licenses/bsd-license.php
;
; THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
; WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
;
; Module Name:
;
; PageFaultHandler.asm
;
; Abstract:
;
; Defines page fault handler used to hook SMM IDT
;
;------------------------------------------------------------------------------
mOriginalHandler PROTO
PageFaultHandler PROTO
.code
PageFaultHandlerHook PROC
push rax ; save all volatile registers
push rcx
push rdx
push r8
push r9
push r10
push r11
add rsp, -20h
call PageFaultHandler
add rsp, 20h
test rax, rax
pop r11
pop r10
pop r9
pop r8
pop rdx
pop rcx
pop rax ; restore all volatile registers
jnz @F
jmp mOriginalHandler
@@:
add rsp, 08h ; skip error code for PF
iretq
PageFaultHandlerHook ENDP
END