diff options
Diffstat (limited to 'Core/IntelFsp2WrapperPkg/Library/BaseFspWrapperApiLib')
5 files changed, 669 insertions, 0 deletions
diff --git a/Core/IntelFsp2WrapperPkg/Library/BaseFspWrapperApiLib/BaseFspWrapperApiLib.inf b/Core/IntelFsp2WrapperPkg/Library/BaseFspWrapperApiLib/BaseFspWrapperApiLib.inf new file mode 100644 index 0000000000..b52cfeb284 --- /dev/null +++ b/Core/IntelFsp2WrapperPkg/Library/BaseFspWrapperApiLib/BaseFspWrapperApiLib.inf @@ -0,0 +1,70 @@ +## @file
+# Provide FSP API related function.
+#
+# Copyright (c) 2014 - 2016, Intel Corporation. All rights reserved.<BR>
+#
+# 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.
+#
+##
+
+################################################################################
+#
+# Defines Section - statements that will be processed to create a Makefile.
+#
+################################################################################
+[Defines]
+ INF_VERSION = 0x00010005
+ BASE_NAME = BaseFspWrapperApiLib
+ FILE_GUID = F42C789F-4D66-49AF-8C73-1AADC00437AC
+ MODULE_TYPE = BASE
+ VERSION_STRING = 1.0
+ LIBRARY_CLASS = FspWrapperApiLib
+
+#
+# The following information is for reference only and not required by the build tools.
+#
+# VALID_ARCHITECTURES = IA32 X64
+#
+
+################################################################################
+#
+# Sources Section - list of files that are required for the build to succeed.
+#
+################################################################################
+
+[Sources]
+ FspWrapperApiLib.c
+
+[Sources.IA32]
+ IA32/DispatchExecute.c
+
+[Sources.X64]
+ X64/DispatchExecute.c
+ X64/Thunk64To32.nasm
+
+################################################################################
+#
+# Package Dependency Section - list of Package files that are required for
+# this module.
+#
+################################################################################
+
+[Packages]
+ MdePkg/MdePkg.dec
+ IntelFsp2Pkg/IntelFsp2Pkg.dec
+ IntelFsp2WrapperPkg/IntelFsp2WrapperPkg.dec
+
+[LibraryClasses]
+ BaseLib
+
+[Guids]
+ gFspHeaderFileGuid ## CONSUMES ## GUID
+
+[Pcd]
+ gIntelFsp2WrapperTokenSpaceGuid.PcdFspmBaseAddress ## CONSUMES
+ gIntelFsp2WrapperTokenSpaceGuid.PcdFspsBaseAddress ## CONSUMES
diff --git a/Core/IntelFsp2WrapperPkg/Library/BaseFspWrapperApiLib/FspWrapperApiLib.c b/Core/IntelFsp2WrapperPkg/Library/BaseFspWrapperApiLib/FspWrapperApiLib.c new file mode 100644 index 0000000000..8cf136fe1a --- /dev/null +++ b/Core/IntelFsp2WrapperPkg/Library/BaseFspWrapperApiLib/FspWrapperApiLib.c @@ -0,0 +1,203 @@ +/** @file
+ Provide FSP API related function.
+
+ Copyright (c) 2014 - 2016, Intel Corporation. All rights reserved.<BR>
+ 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.
+
+**/
+
+#include <PiPei.h>
+
+#include <Library/FspWrapperApiLib.h>
+#include <Library/BaseLib.h>
+#include <Library/BaseMemoryLib.h>
+
+/**
+ Wrapper for a thunk to transition from long mode to compatibility mode to execute 32-bit code and then transit back to
+ long mode.
+
+ @param[in] Function The 32bit code entry to be executed.
+ @param[in] Param1 The first parameter to pass to 32bit code.
+ @param[in] Param2 The second parameter to pass to 32bit code.
+
+ @return EFI_STATUS.
+**/
+EFI_STATUS
+Execute32BitCode (
+ IN UINT64 Function,
+ IN UINT64 Param1,
+ IN UINT64 Param2
+ );
+
+/**
+ Find FSP header pointer.
+
+ @param[in] FlashFvFspBase Flash address of FSP FV.
+
+ @return FSP header pointer.
+**/
+FSP_INFO_HEADER *
+EFIAPI
+FspFindFspHeader (
+ IN EFI_PHYSICAL_ADDRESS FlashFvFspBase
+ )
+{
+ UINT8 *CheckPointer;
+
+ CheckPointer = (UINT8 *) (UINTN) FlashFvFspBase;
+
+ if (((EFI_FIRMWARE_VOLUME_HEADER *)CheckPointer)->Signature != EFI_FVH_SIGNATURE) {
+ return NULL;
+ }
+
+ if (((EFI_FIRMWARE_VOLUME_HEADER *)CheckPointer)->ExtHeaderOffset != 0) {
+ CheckPointer = CheckPointer + ((EFI_FIRMWARE_VOLUME_HEADER *)CheckPointer)->ExtHeaderOffset;
+ CheckPointer = CheckPointer + ((EFI_FIRMWARE_VOLUME_EXT_HEADER *)CheckPointer)->ExtHeaderSize;
+ CheckPointer = (UINT8 *) ALIGN_POINTER (CheckPointer, 8);
+ } else {
+ CheckPointer = CheckPointer + ((EFI_FIRMWARE_VOLUME_HEADER *)CheckPointer)->HeaderLength;
+ }
+
+
+ CheckPointer = CheckPointer + sizeof (EFI_FFS_FILE_HEADER);
+
+ if (((EFI_RAW_SECTION *)CheckPointer)->Type != EFI_SECTION_RAW) {
+ return NULL;
+ }
+
+ CheckPointer = CheckPointer + sizeof (EFI_RAW_SECTION);
+
+ return (FSP_INFO_HEADER *)CheckPointer;
+}
+
+/**
+ Call FSP API - FspNotifyPhase.
+
+ @param[in] NotifyPhaseParams Address pointer to the NOTIFY_PHASE_PARAMS structure.
+
+ @return EFI status returned by FspNotifyPhase API.
+**/
+EFI_STATUS
+EFIAPI
+CallFspNotifyPhase (
+ IN NOTIFY_PHASE_PARAMS *NotifyPhaseParams
+ )
+{
+ FSP_INFO_HEADER *FspHeader;
+ FSP_NOTIFY_PHASE NotifyPhaseApi;
+ EFI_STATUS Status;
+ BOOLEAN InterruptState;
+
+ FspHeader = (FSP_INFO_HEADER *)FspFindFspHeader (PcdGet32 (PcdFspsBaseAddress));
+ if (FspHeader == NULL) {
+ return EFI_DEVICE_ERROR;
+ }
+
+ NotifyPhaseApi = (FSP_NOTIFY_PHASE)(UINTN)(FspHeader->ImageBase + FspHeader->NotifyPhaseEntryOffset);
+ InterruptState = SaveAndDisableInterrupts ();
+ Status = Execute32BitCode ((UINTN)NotifyPhaseApi, (UINTN)NotifyPhaseParams, (UINTN)NULL);
+ SetInterruptState (InterruptState);
+
+ return Status;
+}
+
+/**
+ Call FSP API - FspMemoryInit.
+
+ @param[in] FspmUpdDataPtr Address pointer to the FSP_MEMORY_INIT_PARAMS structure.
+ @param[out] HobListPtr Address of the HobList pointer.
+
+ @return EFI status returned by FspMemoryInit API.
+**/
+EFI_STATUS
+EFIAPI
+CallFspMemoryInit (
+ IN VOID *FspmUpdDataPtr,
+ OUT VOID **HobListPtr
+ )
+{
+ FSP_INFO_HEADER *FspHeader;
+ FSP_MEMORY_INIT FspMemoryInitApi;
+ EFI_STATUS Status;
+ BOOLEAN InterruptState;
+
+ FspHeader = (FSP_INFO_HEADER *)FspFindFspHeader (PcdGet32 (PcdFspmBaseAddress));
+ if (FspHeader == NULL) {
+ return EFI_DEVICE_ERROR;
+ }
+
+ FspMemoryInitApi = (FSP_MEMORY_INIT)(UINTN)(FspHeader->ImageBase + FspHeader->FspMemoryInitEntryOffset);
+ InterruptState = SaveAndDisableInterrupts ();
+ Status = Execute32BitCode ((UINTN)FspMemoryInitApi, (UINTN)FspmUpdDataPtr, (UINTN)HobListPtr);
+ SetInterruptState (InterruptState);
+
+ return Status;
+}
+
+/**
+ Call FSP API - TempRamExit.
+
+ @param[in] TempRamExitParam Address pointer to the TempRamExit parameters structure.
+
+ @return EFI status returned by TempRamExit API.
+**/
+EFI_STATUS
+EFIAPI
+CallTempRamExit (
+ IN VOID *TempRamExitParam
+ )
+{
+ FSP_INFO_HEADER *FspHeader;
+ FSP_TEMP_RAM_EXIT TempRamExitApi;
+ EFI_STATUS Status;
+ BOOLEAN InterruptState;
+
+ FspHeader = (FSP_INFO_HEADER *)FspFindFspHeader (PcdGet32 (PcdFspmBaseAddress));
+ if (FspHeader == NULL) {
+ return EFI_DEVICE_ERROR;
+ }
+
+ TempRamExitApi = (FSP_TEMP_RAM_EXIT)(UINTN)(FspHeader->ImageBase + FspHeader->TempRamExitEntryOffset);
+ InterruptState = SaveAndDisableInterrupts ();
+ Status = Execute32BitCode ((UINTN)TempRamExitApi, (UINTN)TempRamExitParam, (UINTN)NULL);
+ SetInterruptState (InterruptState);
+
+ return Status;
+}
+
+/**
+ Call FSP API - FspSiliconInit.
+
+ @param[in] FspsUpdDataPtr Address pointer to the Silicon Init parameters structure.
+
+ @return EFI status returned by FspSiliconInit API.
+**/
+EFI_STATUS
+EFIAPI
+CallFspSiliconInit (
+ IN VOID *FspsUpdDataPtr
+ )
+{
+ FSP_INFO_HEADER *FspHeader;
+ FSP_SILICON_INIT FspSiliconInitApi;
+ EFI_STATUS Status;
+ BOOLEAN InterruptState;
+
+ FspHeader = (FSP_INFO_HEADER *)FspFindFspHeader (PcdGet32 (PcdFspsBaseAddress));
+ if (FspHeader == NULL) {
+ return EFI_DEVICE_ERROR;
+ }
+
+ FspSiliconInitApi = (FSP_SILICON_INIT)(UINTN)(FspHeader->ImageBase + FspHeader->FspSiliconInitEntryOffset);
+ InterruptState = SaveAndDisableInterrupts ();
+ Status = Execute32BitCode ((UINTN)FspSiliconInitApi, (UINTN)FspsUpdDataPtr, (UINTN)NULL);
+ SetInterruptState (InterruptState);
+
+ return Status;
+}
diff --git a/Core/IntelFsp2WrapperPkg/Library/BaseFspWrapperApiLib/IA32/DispatchExecute.c b/Core/IntelFsp2WrapperPkg/Library/BaseFspWrapperApiLib/IA32/DispatchExecute.c new file mode 100644 index 0000000000..72b1762f4c --- /dev/null +++ b/Core/IntelFsp2WrapperPkg/Library/BaseFspWrapperApiLib/IA32/DispatchExecute.c @@ -0,0 +1,58 @@ +/** @file
+ Execute 32-bit code in Protected Mode.
+
+ Copyright (c) 2014 - 2016, Intel Corporation. All rights reserved.<BR>
+ 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.
+
+**/
+
+#include <Uefi.h>
+#include <FspEas.h>
+
+/**
+ FSP API functions.
+
+ @param[in] Param1 The first parameter to pass to 32bit code.
+ @param[in] Param2 The second parameter to pass to 32bit code.
+
+ @return EFI_STATUS.
+**/
+typedef
+EFI_STATUS
+(EFIAPI *FSP_FUNCTION) (
+ IN VOID *Param1,
+ IN VOID *Param2
+ );
+
+/**
+ Wrapper for a thunk to transition from long mode to compatibility mode to execute 32-bit code and then transit back to
+ long mode.
+
+ @param[in] Function The 32bit code entry to be executed.
+ @param[in] Param1 The first parameter to pass to 32bit code.
+ @param[in] Param2 The second parameter to pass to 32bit code.
+
+ @return EFI_STATUS.
+**/
+EFI_STATUS
+Execute32BitCode (
+ IN UINT64 Function,
+ IN UINT64 Param1,
+ IN UINT64 Param2
+ )
+{
+ FSP_FUNCTION EntryFunc;
+ EFI_STATUS Status;
+
+ EntryFunc = (FSP_FUNCTION) (UINTN) (Function);
+ Status = EntryFunc ((VOID *)(UINTN)Param1, (VOID *)(UINTN)Param2);
+
+ return Status;
+}
+
diff --git a/Core/IntelFsp2WrapperPkg/Library/BaseFspWrapperApiLib/X64/DispatchExecute.c b/Core/IntelFsp2WrapperPkg/Library/BaseFspWrapperApiLib/X64/DispatchExecute.c new file mode 100644 index 0000000000..061d381c1b --- /dev/null +++ b/Core/IntelFsp2WrapperPkg/Library/BaseFspWrapperApiLib/X64/DispatchExecute.c @@ -0,0 +1,108 @@ +/** @file
+ Execute 32-bit code in Long Mode.
+ Provide a thunk function to transition from long mode to compatibility mode to execute 32-bit code and then transit
+ back to long mode.
+
+ Copyright (c) 2014 - 2016, Intel Corporation. All rights reserved.<BR>
+ 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.
+
+**/
+
+#include <Uefi.h>
+#include <Library/BaseLib.h>
+#include <FspEas.h>
+
+#pragma pack(1)
+typedef union {
+ struct {
+ UINT32 LimitLow : 16;
+ UINT32 BaseLow : 16;
+ UINT32 BaseMid : 8;
+ UINT32 Type : 4;
+ UINT32 System : 1;
+ UINT32 Dpl : 2;
+ UINT32 Present : 1;
+ UINT32 LimitHigh : 4;
+ UINT32 Software : 1;
+ UINT32 Reserved : 1;
+ UINT32 DefaultSize : 1;
+ UINT32 Granularity : 1;
+ UINT32 BaseHigh : 8;
+ } Bits;
+ UINT64 Uint64;
+} IA32_GDT;
+#pragma pack()
+
+GLOBAL_REMOVE_IF_UNREFERENCED IA32_GDT mGdtEntries[] = {
+ {{0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0}}, /* 0x0: reserve */
+ {{0xFFFF, 0, 0, 0xB, 1, 0, 1, 0xF, 0, 0, 1, 1, 0}}, /* 0x8: compatibility mode */
+ {{0xFFFF, 0, 0, 0xB, 1, 0, 1, 0xF, 0, 1, 0, 1, 0}}, /* 0x10: for long mode */
+ {{0xFFFF, 0, 0, 0x3, 1, 0, 1, 0xF, 0, 0, 1, 1, 0}}, /* 0x18: data */
+ {{0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0}}, /* 0x20: reserve */
+};
+
+//
+// IA32 Gdt register
+//
+GLOBAL_REMOVE_IF_UNREFERENCED IA32_DESCRIPTOR mGdt = {
+ sizeof (mGdtEntries) - 1,
+ (UINTN) mGdtEntries
+ };
+
+/**
+ Assembly function to transition from long mode to compatibility mode to execute 32-bit code and then transit back to
+ long mode.
+
+ @param[in] Function The 32bit code entry to be executed.
+ @param[in] Param1 The first parameter to pass to 32bit code
+ @param[in] Param2 The second parameter to pass to 32bit code
+ @param[in] InternalGdtr The GDT and GDT descriptor used by this library
+
+ @return status.
+**/
+UINT32
+AsmExecute32BitCode (
+ IN UINT64 Function,
+ IN UINT64 Param1,
+ IN UINT64 Param2,
+ IN IA32_DESCRIPTOR *InternalGdtr
+ );
+
+/**
+ Wrapper for a thunk to transition from long mode to compatibility mode to execute 32-bit code and then transit back to
+ long mode.
+
+ @param[in] Function The 32bit code entry to be executed.
+ @param[in] Param1 The first parameter to pass to 32bit code.
+ @param[in] Param2 The second parameter to pass to 32bit code.
+
+ @return EFI_STATUS.
+**/
+EFI_STATUS
+Execute32BitCode (
+ IN UINT64 Function,
+ IN UINT64 Param1,
+ IN UINT64 Param2
+ )
+{
+ EFI_STATUS Status;
+ IA32_DESCRIPTOR Idtr;
+
+ //
+ // Idtr might be changed inside of FSP. 32bit FSP only knows the <4G address.
+ // If IDTR.Base is >4G, FSP can not handle. So we need save/restore IDTR here for X64 only.
+ // Interrupt is already disabled here, so it is safety to update IDTR.
+ //
+ AsmReadIdtr (&Idtr);
+ Status = AsmExecute32BitCode (Function, Param1, Param2, &mGdt);
+ AsmWriteIdtr (&Idtr);
+
+ return Status;
+}
+
diff --git a/Core/IntelFsp2WrapperPkg/Library/BaseFspWrapperApiLib/X64/Thunk64To32.nasm b/Core/IntelFsp2WrapperPkg/Library/BaseFspWrapperApiLib/X64/Thunk64To32.nasm new file mode 100644 index 0000000000..bcc6d70a73 --- /dev/null +++ b/Core/IntelFsp2WrapperPkg/Library/BaseFspWrapperApiLib/X64/Thunk64To32.nasm @@ -0,0 +1,230 @@ +;
+; Copyright (c) 2016, Intel Corporation. All rights reserved.<BR>
+; 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:
+;
+; Thunk64To32.nasm
+;
+; Abstract:
+;
+; This is the assembly code to transition from long mode to compatibility mode to execute 32-bit code and then
+; transit back to long mode.
+;
+;-------------------------------------------------------------------------------
+ DEFAULT REL
+ SECTION .text
+;----------------------------------------------------------------------------
+; Procedure: AsmExecute32BitCode
+;
+; Input: None
+;
+; Output: None
+;
+; Prototype: UINT32
+; AsmExecute32BitCode (
+; IN UINT64 Function,
+; IN UINT64 Param1,
+; IN UINT64 Param2,
+; IN IA32_DESCRIPTOR *InternalGdtr
+; );
+;
+;
+; Description: A thunk function to execute 32-bit code in long mode.
+;
+;----------------------------------------------------------------------------
+global ASM_PFX(AsmExecute32BitCode)
+ASM_PFX(AsmExecute32BitCode):
+ ;
+ ; save IFLAG and disable it
+ ;
+ pushfq
+ cli
+
+ ;
+ ; save orignal GDTR and CS
+ ;
+ mov rax, ds
+ push rax
+ mov rax, cs
+ push rax
+ sub rsp, 0x10
+ sgdt [rsp]
+ ;
+ ; load internal GDT
+ ;
+ lgdt [r9]
+ ;
+ ; Save general purpose register and rflag register
+ ;
+ pushfq
+ push rdi
+ push rsi
+ push rbp
+ push rbx
+
+ ;
+ ; save CR3
+ ;
+ mov rax, cr3
+ mov rbp, rax
+
+ ;
+ ; Prepare the CS and return address for the transition from 32-bit to 64-bit mode
+ ;
+ mov rax, dword 0x10 ; load long mode selector
+ shl rax, 32
+ mov r9, ReloadCS ;Assume the ReloadCS is under 4G
+ or rax, r9
+ push rax
+ ;
+ ; Save parameters for 32-bit function call
+ ;
+ mov rax, r8
+ shl rax, 32
+ or rax, rdx
+ push rax
+ ;
+ ; save the 32-bit function entry and the return address into stack which will be
+ ; retrieve in compatibility mode.
+ ;
+ mov rax, ReturnBack ;Assume the ReloadCS is under 4G
+ shl rax, 32
+ or rax, rcx
+ push rax
+
+ ;
+ ; let rax save DS
+ ;
+ mov rax, dword 0x18
+
+ ;
+ ; Change to Compatible Segment
+ ;
+ mov rcx, dword 0x8 ; load compatible mode selector
+ shl rcx, 32
+ mov rdx, Compatible ; assume address < 4G
+ or rcx, rdx
+ push rcx
+ retf
+
+Compatible:
+ ; reload DS/ES/SS to make sure they are correct referred to current GDT
+ mov ds, ax
+ mov es, ax
+ mov ss, ax
+
+ ;
+ ; Disable paging
+ ;
+ mov rcx, cr0
+ btc ecx, 31
+ mov cr0, rcx
+ ;
+ ; Clear EFER.LME
+ ;
+ mov ecx, 0xC0000080
+ rdmsr
+ btc eax, 8
+ wrmsr
+
+; Now we are in protected mode
+ ;
+ ; Call 32-bit function. Assume the function entry address and parameter value is less than 4G
+ ;
+ pop rax ; Here is the function entry
+ ;
+ ; Now the parameter is at the bottom of the stack, then call in to IA32 function.
+ ;
+ jmp rax
+ReturnBack:
+ mov ebx, eax ; save return status
+ pop rcx ; drop param1
+ pop rcx ; drop param2
+
+ ;
+ ; restore CR4
+ ;
+ mov rax, cr4
+ bts eax, 5
+ mov cr4, rax
+
+ ;
+ ; restore CR3
+ ;
+ mov eax, ebp
+ mov cr3, rax
+
+ ;
+ ; Set EFER.LME to re-enable ia32-e
+ ;
+ mov ecx, 0xC0000080
+ rdmsr
+ bts eax, 8
+ wrmsr
+ ;
+ ; Enable paging
+ ;
+ mov rax, cr0
+ bts eax, 31
+ mov cr0, rax
+; Now we are in compatible mode
+
+ ;
+ ; Reload cs register
+ ;
+ retf
+ReloadCS:
+ ;
+ ; Now we're in Long Mode
+ ;
+ ;
+ ; Restore C register and eax hold the return status from 32-bit function.
+ ; Note: Do not touch rax from now which hold the return value from IA32 function
+ ;
+ mov eax, ebx ; put return status to EAX
+ pop rbx
+ pop rbp
+ pop rsi
+ pop rdi
+ popfq
+ ;
+ ; Switch to orignal GDT and CS. here rsp is pointer to the orignal GDT descriptor.
+ ;
+ lgdt [rsp]
+ ;
+ ; drop GDT descriptor in stack
+ ;
+ add rsp, 0x10
+ ;
+ ; switch to orignal CS and GDTR
+ ;
+ pop r9 ; get CS
+ shl r9, 32 ; rcx[32..47] <- Cs
+ mov rcx, .0
+ or rcx, r9
+ push rcx
+ retf
+.0:
+ ;
+ ; Reload original DS/ES/SS
+ ;
+ pop rcx
+ mov ds, rcx
+ mov es, rcx
+ mov ss, rcx
+
+ ;
+ ; Restore IFLAG
+ ;
+ popfq
+
+ ret
+
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