Current implementation uses following two methods
EnableNullDetection()
DisableNullDetection()
to enable/disable page 0. These two methods will check PCD
PcdNullPointerDetectionPropertyMask to know if the page 0 is disabled or not.
This is due to the fact that old GCD service doesn't provide paging related
attributes of memory block. Since this issue has been fixed, GCD services
can be used to determine the paging status of page 0. This is also make it
possible to just use a new macro
ACCESS_PAGE0_CODE(
{
<code accessing page 0>
}
);
to replace above methods to do the same job, which also makes code more
readability.
Cc: Liming Gao <liming....@intel.com>
Cc: Michael D Kinney <michael.d.kin...@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Jian J Wang <jian.j.w...@intel.com>
---
.../Csm/LegacyBiosDxe/LegacyBda.c | 53 ++++----
.../Csm/LegacyBiosDxe/LegacyBios.c | 135 ++-------------------
.../Csm/LegacyBiosDxe/LegacyBiosDxe.inf | 1 -
.../Csm/LegacyBiosDxe/LegacyBiosInterface.h | 16 ---
.../Csm/LegacyBiosDxe/LegacyBootSupport.c | 80 ++++++------
.../Csm/LegacyBiosDxe/LegacyPci.c | 72 ++++++-----
IntelFrameworkModulePkg/Csm/LegacyBiosDxe/Thunk.c | 51 ++++----
7 files changed, 135 insertions(+), 273 deletions(-)
diff --git a/IntelFrameworkModulePkg/Csm/LegacyBiosDxe/LegacyBda.c
b/IntelFrameworkModulePkg/Csm/LegacyBiosDxe/LegacyBda.c
index c6670febee..9667dc2a0f 100644
--- a/IntelFrameworkModulePkg/Csm/LegacyBiosDxe/LegacyBda.c
+++ b/IntelFrameworkModulePkg/Csm/LegacyBiosDxe/LegacyBda.c
@@ -34,37 +34,36 @@ LegacyBiosInitBda (
BDA_STRUC *Bda;
UINT8 *Ebda;
- DisableNullDetection ();
-
Bda = (BDA_STRUC *) ((UINTN) 0x400);
Ebda = (UINT8 *) ((UINTN) 0x9fc00);
- ZeroMem (Bda, 0x100);
+ ACCESS_PAGE0_CODE ({
+ ZeroMem (Bda, 0x100);
+ //
+ // 640k-1k for EBDA
+ //
+ Bda->MemSize = 0x27f;
+ Bda->KeyHead = 0x1e;
+ Bda->KeyTail = 0x1e;
+ Bda->FloppyData = 0x00;
+ Bda->FloppyTimeout = 0xff;
+
+ Bda->KeyStart = 0x001E;
+ Bda->KeyEnd = 0x003E;
+ Bda->KeyboardStatus = 0x10;
+ Bda->Ebda = 0x9fc0;
+
+ //
+ // Move LPT time out here and zero out LPT4 since some SCSI OPROMS
+ // use this as scratch pad (LPT4 is Reserved)
+ //
+ Bda->Lpt1_2Timeout = 0x1414;
+ Bda->Lpt3_4Timeout = 0x1400;
+
+ });
+
ZeroMem (Ebda, 0x400);
- //
- // 640k-1k for EBDA
- //
- Bda->MemSize = 0x27f;
- Bda->KeyHead = 0x1e;
- Bda->KeyTail = 0x1e;
- Bda->FloppyData = 0x00;
- Bda->FloppyTimeout = 0xff;
-
- Bda->KeyStart = 0x001E;
- Bda->KeyEnd = 0x003E;
- Bda->KeyboardStatus = 0x10;
- Bda->Ebda = 0x9fc0;
-
- //
- // Move LPT time out here and zero out LPT4 since some SCSI OPROMS
- // use this as scratch pad (LPT4 is Reserved)
- //
- Bda->Lpt1_2Timeout = 0x1414;
- Bda->Lpt3_4Timeout = 0x1400;
-
- *Ebda = 0x01;
-
- EnableNullDetection ();
+ *Ebda = 0x01;
return EFI_SUCCESS;
}
diff --git a/IntelFrameworkModulePkg/Csm/LegacyBiosDxe/LegacyBios.c
b/IntelFrameworkModulePkg/Csm/LegacyBiosDxe/LegacyBios.c
index c6461f5547..d50c15eacb 100644
--- a/IntelFrameworkModulePkg/Csm/LegacyBiosDxe/LegacyBios.c
+++ b/IntelFrameworkModulePkg/Csm/LegacyBiosDxe/LegacyBios.c
@@ -786,115 +786,6 @@ ToggleEndOfDxeStatus (
return;
}
-//
-// Legacy BIOS needs to access memory between 0-4095, which will cause page
-// fault exception if NULL pointer detection mechanism is enabled. Following
-// functions can be used to disable/enable NULL pointer detection before/after
-// accessing those memory.
-//
-
-/**
- Enable NULL pointer detection.
-**/
-VOID
-EnableNullDetection (
- VOID
- )
-{
- EFI_STATUS Status;
- EFI_GCD_MEMORY_SPACE_DESCRIPTOR Desc;
-
- if (((PcdGet8 (PcdNullPointerDetectionPropertyMask) & BIT0) == 0)
- ||
- ((mEndOfDxe) &&
- ((PcdGet8 (PcdNullPointerDetectionPropertyMask) & (BIT7|BIT0))
- == (BIT7|BIT0)))
- ) {
- return;
- }
-
- //
- // Check current capabilities and attributes
- //
- Status = gDS->GetMemorySpaceDescriptor (0, &Desc);
- ASSERT_EFI_ERROR (Status);
-
- //
- // Try to add EFI_MEMORY_RP support if necessary
- //
- if ((Desc.Capabilities & EFI_MEMORY_RP) == 0) {
- Desc.Capabilities |= EFI_MEMORY_RP;
- Status = gDS->SetMemorySpaceCapabilities (0, EFI_PAGES_TO_SIZE(1),
- Desc.Capabilities);
- ASSERT_EFI_ERROR (Status);
- if (EFI_ERROR (Status)) {
- return;
- }
- }
-
- //
- // Don't bother if EFI_MEMORY_RP is already set.
- //
- if ((Desc.Attributes & EFI_MEMORY_RP) == 0) {
- Desc.Attributes |= EFI_MEMORY_RP;
- Status = gDS->SetMemorySpaceAttributes (0, EFI_PAGES_TO_SIZE(1),
- Desc.Attributes);
- ASSERT_EFI_ERROR (Status);
- }
-}
-
-/**
- Disable NULL pointer detection.
-**/
-VOID
-DisableNullDetection (
- VOID
- )
-{
- EFI_STATUS Status;
- EFI_GCD_MEMORY_SPACE_DESCRIPTOR Desc;
-
- if (((PcdGet8 (PcdNullPointerDetectionPropertyMask) & BIT0) == 0)
- ||
- ((mEndOfDxe) &&
- ((PcdGet8 (PcdNullPointerDetectionPropertyMask) & (BIT7|BIT0))
- == (BIT7|BIT0)))
- ) {
- return;
- }
-
- //
- // Check current capabilities and attributes
- //
- Status = gDS->GetMemorySpaceDescriptor (0, &Desc);
- ASSERT_EFI_ERROR (Status);
-
- //
- // Try to add EFI_MEMORY_RP support if necessary
- //
- if ((Desc.Capabilities & EFI_MEMORY_RP) == 0) {
- Desc.Capabilities |= EFI_MEMORY_RP;
- Status = gDS->SetMemorySpaceCapabilities (0, EFI_PAGES_TO_SIZE(1),
- Desc.Capabilities);
- ASSERT_EFI_ERROR (Status);
- if (EFI_ERROR (Status)) {
- return;
- }
- }
-
- //
- // Don't bother if EFI_MEMORY_RP is already cleared.
- //
- if ((Desc.Attributes & EFI_MEMORY_RP) != 0) {
- Desc.Attributes &= ~EFI_MEMORY_RP;
- Status = gDS->SetMemorySpaceAttributes (0, EFI_PAGES_TO_SIZE(1),
- Desc.Attributes);
- ASSERT_EFI_ERROR (Status);
- } else {
- DEBUG ((DEBUG_WARN, "!!! Page 0 is supposed to be disabled !!!\r\n"));
- }
-}
-
/**
Install Driver to produce Legacy BIOS protocol.
@@ -1095,10 +986,10 @@ LegacyBiosInstall (
// Initialize region from 0x0000 to 4k. This initializes interrupt vector
// range.
//
- DisableNullDetection ();
- gBS->SetMem ((VOID *) ClearPtr, 0x400, INITIAL_VALUE_BELOW_1K);
- ZeroMem ((VOID *) ((UINTN)ClearPtr + 0x400), 0xC00);
- EnableNullDetection ();
+ ACCESS_PAGE0_CODE ({
+ gBS->SetMem ((VOID *) ClearPtr, 0x400, INITIAL_VALUE_BELOW_1K);
+ ZeroMem ((VOID *) ((UINTN)ClearPtr + 0x400), 0xC00);
+ });
//
// Allocate pages for OPROM usage
@@ -1237,16 +1128,14 @@ LegacyBiosInstall (
//
// Save Unexpected interrupt vector so can restore it just prior to boot
//
- DisableNullDetection ();
-
- BaseVectorMaster = (UINT32 *) (sizeof (UINT32) *
PROTECTED_MODE_BASE_VECTOR_MASTER);
- Private->BiosUnexpectedInt = BaseVectorMaster[0];
- IntRedirCode = (UINT32) (UINTN) Private->IntThunk->InterruptRedirectionCode;
- for (Index = 0; Index < 8; Index++) {
- BaseVectorMaster[Index] = (EFI_SEGMENT (IntRedirCode + Index * 4) << 16) |
EFI_OFFSET (IntRedirCode + Index * 4);
- }
-
- EnableNullDetection ();
+ ACCESS_PAGE0_CODE ({
+ BaseVectorMaster = (UINT32 *) (sizeof (UINT32) *
PROTECTED_MODE_BASE_VECTOR_MASTER);
+ Private->BiosUnexpectedInt = BaseVectorMaster[0];
+ IntRedirCode = (UINT32) (UINTN)
Private->IntThunk->InterruptRedirectionCode;
+ for (Index = 0; Index < 8; Index++) {
+ BaseVectorMaster[Index] = (EFI_SEGMENT (IntRedirCode + Index * 4) << 16)
| EFI_OFFSET (IntRedirCode + Index * 4);
+ }
+ });
//
// Save EFI value
diff --git a/IntelFrameworkModulePkg/Csm/LegacyBiosDxe/LegacyBiosDxe.inf
b/IntelFrameworkModulePkg/Csm/LegacyBiosDxe/LegacyBiosDxe.inf
index 6efc7f36ae..180c18e3fc 100644
--- a/IntelFrameworkModulePkg/Csm/LegacyBiosDxe/LegacyBiosDxe.inf
+++ b/IntelFrameworkModulePkg/Csm/LegacyBiosDxe/LegacyBiosDxe.inf
@@ -148,7 +148,6 @@
gEfiIntelFrameworkModulePkgTokenSpaceGuid.PcdHighPmmMemorySize
## CONSUMES
gEfiIntelFrameworkModulePkgTokenSpaceGuid.PcdOpromReservedMemoryBase
## CONSUMES
gEfiIntelFrameworkModulePkgTokenSpaceGuid.PcdOpromReservedMemorySize
## CONSUMES
- gEfiMdeModulePkgTokenSpaceGuid.PcdNullPointerDetectionPropertyMask ##
CONSUMES
[Depex]
gEfiLegacyRegion2ProtocolGuid AND gEfiLegacyInterruptProtocolGuid AND
gEfiLegacyBiosPlatformProtocolGuid AND gEfiLegacy8259ProtocolGuid AND
gEfiGenericMemTestProtocolGuid AND gEfiCpuArchProtocolGuid AND
gEfiTimerArchProtocolGuid AND gEfiVariableWriteArchProtocolGuid
diff --git a/IntelFrameworkModulePkg/Csm/LegacyBiosDxe/LegacyBiosInterface.h
b/IntelFrameworkModulePkg/Csm/LegacyBiosDxe/LegacyBiosInterface.h
index 86a3b09080..cc2fc9fc13 100644
--- a/IntelFrameworkModulePkg/Csm/LegacyBiosDxe/LegacyBiosInterface.h
+++ b/IntelFrameworkModulePkg/Csm/LegacyBiosDxe/LegacyBiosInterface.h
@@ -1544,20 +1544,4 @@ LegacyBiosInstallVgaRom (
IN LEGACY_BIOS_INSTANCE *Private
);
-/**
- Enable NULL pointer detection.
-**/
-VOID
-EnableNullDetection (
- VOID
- );
-
-/**
- Disable NULL pointer detection.
-**/
-VOID
-DisableNullDetection (
- VOID
- );
-
#endif
diff --git a/IntelFrameworkModulePkg/Csm/LegacyBiosDxe/LegacyBootSupport.c
b/IntelFrameworkModulePkg/Csm/LegacyBiosDxe/LegacyBootSupport.c
index c2ac69ce69..d65a751fe7 100644
--- a/IntelFrameworkModulePkg/Csm/LegacyBiosDxe/LegacyBootSupport.c
+++ b/IntelFrameworkModulePkg/Csm/LegacyBiosDxe/LegacyBootSupport.c
@@ -1041,7 +1041,9 @@ GenericLegacyBoot (
//
// Setup BDA and EBDA standard areas before Legacy Boot
//
- LegacyBiosCompleteBdaBeforeBoot (Private);
+ ACCESS_PAGE0_CODE ({
+ LegacyBiosCompleteBdaBeforeBoot (Private);
+ });
LegacyBiosCompleteStandardCmosBeforeBoot (Private);
//
@@ -1073,10 +1075,10 @@ GenericLegacyBoot (
// Use 182/10 to avoid floating point math.
//
LocalTime = (LocalTime * 182) / 10;
- DisableNullDetection ();
- BdaPtr = (UINT32 *) (UINTN)0x46C;
- *BdaPtr = LocalTime;
- EnableNullDetection ();
+ ACCESS_PAGE0_CODE ({
+ BdaPtr = (UINT32 *) (UINTN)0x46C;
+ *BdaPtr = LocalTime;
+ });
//
// Shadow PCI ROMs. We must do this near the end since this will kick
@@ -1322,15 +1324,15 @@ GenericLegacyBoot (
// set of TIANO vectors) or takes it over.
//
//
- DisableNullDetection ();
- BaseVectorMaster = (UINT32 *) (sizeof (UINT32) *
PROTECTED_MODE_BASE_VECTOR_MASTER);
- for (Index = 0; Index < 8; Index++) {
- Private->ThunkSavedInt[Index] = BaseVectorMaster[Index];
- if (Private->ThunkSeg == (UINT16) (BaseVectorMaster[Index] >> 16)) {
- BaseVectorMaster[Index] = (UINT32) (Private->BiosUnexpectedInt);
+ ACCESS_PAGE0_CODE ({
+ BaseVectorMaster = (UINT32 *) (sizeof (UINT32) *
PROTECTED_MODE_BASE_VECTOR_MASTER);
+ for (Index = 0; Index < 8; Index++) {
+ Private->ThunkSavedInt[Index] = BaseVectorMaster[Index];
+ if (Private->ThunkSeg == (UINT16) (BaseVectorMaster[Index] >> 16)) {
+ BaseVectorMaster[Index] = (UINT32) (Private->BiosUnexpectedInt);
+ }
}
- }
- EnableNullDetection ();
+ });
ZeroMem (&Regs, sizeof (EFI_IA32_REGISTER_SET));
Regs.X.AX = Legacy16Boot;
@@ -1344,12 +1346,12 @@ GenericLegacyBoot (
0
);
- DisableNullDetection ();
- BaseVectorMaster = (UINT32 *) (sizeof (UINT32) *
PROTECTED_MODE_BASE_VECTOR_MASTER);
- for (Index = 0; Index < 8; Index++) {
- BaseVectorMaster[Index] = Private->ThunkSavedInt[Index];
- }
- EnableNullDetection ();
+ ACCESS_PAGE0_CODE ({
+ BaseVectorMaster = (UINT32 *) (sizeof (UINT32) *
PROTECTED_MODE_BASE_VECTOR_MASTER);
+ for (Index = 0; Index < 8; Index++) {
+ BaseVectorMaster[Index] = Private->ThunkSavedInt[Index];
+ }
+ });
}
Private->LegacyBootEntered = TRUE;
if ((mBootMode == BOOT_LEGACY_OS) || (mBootMode ==
BOOT_UNCONVENTIONAL_DEVICE)) {
@@ -1737,11 +1739,11 @@ LegacyBiosBuildE820 (
//
// First entry is 0 to (640k - EBDA)
//
- DisableNullDetection ();
- E820Table[0].BaseAddr = 0;
- E820Table[0].Length = (UINT64) ((*(UINT16 *) (UINTN)0x40E) << 4);
- E820Table[0].Type = EfiAcpiAddressRangeMemory;
- EnableNullDetection ();
+ ACCESS_PAGE0_CODE ({
+ E820Table[0].BaseAddr = 0;
+ E820Table[0].Length = (UINT64) ((*(UINT16 *) (UINTN)0x40E) << 4);
+ E820Table[0].Type = EfiAcpiAddressRangeMemory;
+ });
//
// Second entry is (640k - EBDA) to 640k
@@ -1975,8 +1977,6 @@ LegacyBiosCompleteBdaBeforeBoot (
UINT16 MachineConfig;
DEVICE_PRODUCER_DATA_HEADER *SioPtr;
- DisableNullDetection ();
-
Bda = (BDA_STRUC *) ((UINTN) 0x400);
MachineConfig = 0;
@@ -2035,8 +2035,6 @@ LegacyBiosCompleteBdaBeforeBoot (
MachineConfig = (UINT16) (MachineConfig + 0x00 + 0x02 +
(SioPtr->MousePresent * 0x04));
Bda->MachineConfig = MachineConfig;
- EnableNullDetection ();
-
return EFI_SUCCESS;
}
@@ -2063,17 +2061,15 @@ LegacyBiosUpdateKeyboardLedStatus (
Private = LEGACY_BIOS_INSTANCE_FROM_THIS (This);
- DisableNullDetection ();
-
- Bda = (BDA_STRUC *) ((UINTN) 0x400);
- LocalLeds = Leds;
- Bda->LedStatus = (UINT8) ((Bda->LedStatus &~0x07) | LocalLeds);
- LocalLeds = (UINT8) (LocalLeds << 4);
- Bda->ShiftStatus = (UINT8) ((Bda->ShiftStatus &~0x70) | LocalLeds);
- LocalLeds = (UINT8) (Leds & 0x20);
- Bda->KeyboardStatus = (UINT8) ((Bda->KeyboardStatus &~0x20) | LocalLeds);
-
- EnableNullDetection ();
+ ACCESS_PAGE0_CODE ({
+ Bda = (BDA_STRUC *) ((UINTN) 0x400);
+ LocalLeds = Leds;
+ Bda->LedStatus = (UINT8) ((Bda->LedStatus &~0x07) | LocalLeds);
+ LocalLeds = (UINT8) (LocalLeds << 4);
+ Bda->ShiftStatus = (UINT8) ((Bda->ShiftStatus &~0x70) | LocalLeds);
+ LocalLeds = (UINT8) (Leds & 0x20);
+ Bda->KeyboardStatus = (UINT8) ((Bda->KeyboardStatus &~0x20) | LocalLeds);
+ });
//
// Call into Legacy16 code to allow it to do any processing
@@ -2119,9 +2115,9 @@ LegacyBiosCompleteStandardCmosBeforeBoot (
// to large capacity drives
// CMOS 14 = BDA 40:10 plus bit 3(display enabled)
//
- DisableNullDetection ();
- Bda = (UINT8)(*((UINT8 *)((UINTN)0x410)) | BIT3);
- EnableNullDetection ();
+ ACCESS_PAGE0_CODE ({
+ Bda = (UINT8)(*((UINT8 *)((UINTN)0x410)) | BIT3);
+ });
//
// Force display enabled
diff --git a/IntelFrameworkModulePkg/Csm/LegacyBiosDxe/LegacyPci.c
b/IntelFrameworkModulePkg/Csm/LegacyBiosDxe/LegacyPci.c
index d38cef3e33..c317d21055 100644
--- a/IntelFrameworkModulePkg/Csm/LegacyBiosDxe/LegacyPci.c
+++ b/IntelFrameworkModulePkg/Csm/LegacyBiosDxe/LegacyPci.c
@@ -2403,35 +2403,33 @@ LegacyBiosInstallRom (
// 2. BBS compliants drives will not change 40:75 until boot time.
// 3. Onboard IDE controllers will change 40:75
//
- DisableNullDetection ();
-
- LocalDiskStart = (UINT8) ((*(UINT8 *) ((UINTN) 0x475)) + 0x80);
- if ((Private->Disk4075 + 0x80) < LocalDiskStart) {
- //
- // Update table since onboard IDE drives found
- //
- Private->LegacyEfiHddTable[Private->LegacyEfiHddTableIndex].PciSegment
= 0xff;
- Private->LegacyEfiHddTable[Private->LegacyEfiHddTableIndex].PciBus
= 0xff;
- Private->LegacyEfiHddTable[Private->LegacyEfiHddTableIndex].PciDevice
= 0xff;
- Private->LegacyEfiHddTable[Private->LegacyEfiHddTableIndex].PciFunction
= 0xff;
- Private->LegacyEfiHddTable[Private->LegacyEfiHddTableIndex].StartDriveNumber
= (UINT8) (Private->Disk4075 + 0x80);
- Private->LegacyEfiHddTable[Private->LegacyEfiHddTableIndex].EndDriveNumber
= LocalDiskStart;
- Private->LegacyEfiHddTableIndex ++;
- Private->Disk4075 = (UINT8) (LocalDiskStart & 0x7f);
- Private->DiskEnd = LocalDiskStart;
- }
-
- if (PciHandle != mVgaHandle) {
+ ACCESS_PAGE0_CODE ({
+ LocalDiskStart = (UINT8) ((*(UINT8 *) ((UINTN) 0x475)) + 0x80);
+ if ((Private->Disk4075 + 0x80) < LocalDiskStart) {
+ //
+ // Update table since onboard IDE drives found
+ //
+ Private->LegacyEfiHddTable[Private->LegacyEfiHddTableIndex].PciSegment
= 0xff;
+ Private->LegacyEfiHddTable[Private->LegacyEfiHddTableIndex].PciBus
= 0xff;
+ Private->LegacyEfiHddTable[Private->LegacyEfiHddTableIndex].PciDevice
= 0xff;
+ Private->LegacyEfiHddTable[Private->LegacyEfiHddTableIndex].PciFunction
= 0xff;
+
Private->LegacyEfiHddTable[Private->LegacyEfiHddTableIndex].StartDriveNumber =
(UINT8) (Private->Disk4075 + 0x80);
+
Private->LegacyEfiHddTable[Private->LegacyEfiHddTableIndex].EndDriveNumber =
LocalDiskStart;
+ Private->LegacyEfiHddTableIndex ++;
+ Private->Disk4075 = (UINT8) (LocalDiskStart & 0x7f);
+ Private->DiskEnd = LocalDiskStart;
+ }
- EnablePs2Keyboard ();
+ if (PciHandle != mVgaHandle) {
- //
- // Store current mode settings since PrepareToScanRom may change mode.
- //
- VideoMode = *(UINT8 *) ((UINTN) (0x400 + BDA_VIDEO_MODE));
- }
+ EnablePs2Keyboard ();
- EnableNullDetection ();
+ //
+ // Store current mode settings since PrepareToScanRom may change mode.
+ //
+ VideoMode = *(UINT8 *) ((UINTN) (0x400 + BDA_VIDEO_MODE));
+ }
+ });
//
// Notify the platform that we are about to scan the ROM
@@ -2473,11 +2471,11 @@ LegacyBiosInstallRom (
// Multiply result by 18.2 for number of ticks since midnight.
// Use 182/10 to avoid floating point math.
//
- DisableNullDetection ();
- LocalTime = (LocalTime * 182) / 10;
- BdaPtr = (UINT32 *) ((UINTN) 0x46C);
- *BdaPtr = LocalTime;
- EnableNullDetection ();
+ ACCESS_PAGE0_CODE ({
+ LocalTime = (LocalTime * 182) / 10;
+ BdaPtr = (UINT32 *) ((UINTN) 0x46C);
+ *BdaPtr = LocalTime;
+ });
//
// Pass in handoff data
@@ -2573,9 +2571,9 @@ LegacyBiosInstallRom (
//
// Set mode settings since PrepareToScanRom may change mode
//
- DisableNullDetection ();
- OldVideoMode = *(UINT8 *) ((UINTN) (0x400 + BDA_VIDEO_MODE));
- EnableNullDetection ();
+ ACCESS_PAGE0_CODE ({
+ OldVideoMode = *(UINT8 *) ((UINTN) (0x400 + BDA_VIDEO_MODE));
+ });
if (VideoMode != OldVideoMode) {
//
@@ -2617,9 +2615,9 @@ LegacyBiosInstallRom (
}
}
- DisableNullDetection ();
- LocalDiskEnd = (UINT8) ((*(UINT8 *) ((UINTN) 0x475)) + 0x80);
- EnableNullDetection ();
+ ACCESS_PAGE0_CODE ({
+ LocalDiskEnd = (UINT8) ((*(UINT8 *) ((UINTN) 0x475)) + 0x80);
+ });
//
// Allow platform to perform any required actions after the
diff --git a/IntelFrameworkModulePkg/Csm/LegacyBiosDxe/Thunk.c
b/IntelFrameworkModulePkg/Csm/LegacyBiosDxe/Thunk.c
index d249479c56..d975d94e70 100644
--- a/IntelFrameworkModulePkg/Csm/LegacyBiosDxe/Thunk.c
+++ b/IntelFrameworkModulePkg/Csm/LegacyBiosDxe/Thunk.c
@@ -73,10 +73,10 @@ LegacyBiosInt86 (
// The base address of legacy interrupt vector table is 0.
// We use this base address to get the legacy interrupt handler.
//
- DisableNullDetection ();
- Segment = (UINT16)(((UINT32 *)0)[BiosInt] >> 16);
- Offset = (UINT16)((UINT32 *)0)[BiosInt];
- EnableNullDetection ();
+ ACCESS_PAGE0_CODE ({
