mirror of https://github.com/acidanthera/audk.git
235 lines
6.3 KiB
NASM
235 lines
6.3 KiB
NASM
;------------------------------------------------------------------------------ ;
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; Copyright (c) 2016 - 2018, Intel Corporation. All rights reserved.<BR>
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; This program and the accompanying materials
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; are licensed and made available under the terms and conditions of the BSD License
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; which accompanies this distribution. The full text of the license may be found at
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; http://opensource.org/licenses/bsd-license.php.
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;
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; THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
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; WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
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;
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; Module Name:
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;
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; SmiEntry.nasm
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;
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; Abstract:
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;
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; Code template of the SMI handler for a particular processor
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;
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;-------------------------------------------------------------------------------
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;
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; Variables referrenced by C code
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;
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%define MSR_IA32_MISC_ENABLE 0x1A0
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%define MSR_EFER 0xc0000080
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%define MSR_EFER_XD 0x800
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;
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; Constants relating to PROCESSOR_SMM_DESCRIPTOR
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;
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%define DSC_OFFSET 0xfb00
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%define DSC_GDTPTR 0x30
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%define DSC_GDTSIZ 0x38
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%define DSC_CS 14
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%define DSC_DS 16
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%define DSC_SS 18
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%define DSC_OTHERSEG 20
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;
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; Constants relating to CPU State Save Area
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;
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%define SSM_DR6 0xffd0
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%define SSM_DR7 0xffc8
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%define PROTECT_MODE_CS 0x8
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%define PROTECT_MODE_DS 0x20
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%define LONG_MODE_CS 0x38
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%define TSS_SEGMENT 0x40
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%define GDT_SIZE 0x50
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extern ASM_PFX(SmiRendezvous)
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extern ASM_PFX(gSmiHandlerIdtr)
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extern ASM_PFX(CpuSmmDebugEntry)
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extern ASM_PFX(CpuSmmDebugExit)
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global ASM_PFX(gSmbase)
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global ASM_PFX(mXdSupported)
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global ASM_PFX(gSmiStack)
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global ASM_PFX(gSmiCr3)
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global ASM_PFX(gcSmiHandlerTemplate)
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global ASM_PFX(gcSmiHandlerSize)
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DEFAULT REL
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SECTION .text
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BITS 16
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ASM_PFX(gcSmiHandlerTemplate):
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_SmiEntryPoint:
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mov bx, _GdtDesc - _SmiEntryPoint + 0x8000
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mov ax,[cs:DSC_OFFSET + DSC_GDTSIZ]
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dec ax
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mov [cs:bx], ax
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mov eax, [cs:DSC_OFFSET + DSC_GDTPTR]
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mov [cs:bx + 2], eax
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o32 lgdt [cs:bx] ; lgdt fword ptr cs:[bx]
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mov ax, PROTECT_MODE_CS
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mov [cs:bx-0x2],ax
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DB 0x66, 0xbf ; mov edi, SMBASE
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ASM_PFX(gSmbase): DD 0
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lea eax, [edi + (@ProtectedMode - _SmiEntryPoint) + 0x8000]
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mov [cs:bx-0x6],eax
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mov ebx, cr0
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and ebx, 0x9ffafff3
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or ebx, 0x23
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mov cr0, ebx
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jmp dword 0x0:0x0
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_GdtDesc:
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DW 0
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DD 0
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BITS 32
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@ProtectedMode:
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mov ax, PROTECT_MODE_DS
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o16 mov ds, ax
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o16 mov es, ax
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o16 mov fs, ax
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o16 mov gs, ax
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o16 mov ss, ax
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DB 0xbc ; mov esp, imm32
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ASM_PFX(gSmiStack): DD 0
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jmp ProtFlatMode
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BITS 64
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ProtFlatMode:
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DB 0xb8 ; mov eax, offset gSmiCr3
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ASM_PFX(gSmiCr3): DD 0
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mov cr3, rax
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mov eax, 0x668 ; as cr4.PGE is not set here, refresh cr3
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mov cr4, rax ; in PreModifyMtrrs() to flush TLB.
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; Load TSS
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sub esp, 8 ; reserve room in stack
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sgdt [rsp]
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mov eax, [rsp + 2] ; eax = GDT base
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add esp, 8
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mov dl, 0x89
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mov [rax + TSS_SEGMENT + 5], dl ; clear busy flag
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mov eax, TSS_SEGMENT
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ltr ax
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; enable NXE if supported
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DB 0xb0 ; mov al, imm8
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ASM_PFX(mXdSupported): DB 1
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cmp al, 0
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jz @SkipXd
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;
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; Check XD disable bit
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;
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mov ecx, MSR_IA32_MISC_ENABLE
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rdmsr
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sub esp, 4
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push rdx ; save MSR_IA32_MISC_ENABLE[63-32]
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test edx, BIT2 ; MSR_IA32_MISC_ENABLE[34]
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jz .0
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and dx, 0xFFFB ; clear XD Disable bit if it is set
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wrmsr
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.0:
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mov ecx, MSR_EFER
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rdmsr
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or ax, MSR_EFER_XD ; enable NXE
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wrmsr
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jmp @XdDone
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@SkipXd:
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sub esp, 8
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@XdDone:
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; Switch into @LongMode
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push LONG_MODE_CS ; push cs hardcore here
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call Base ; push return address for retf later
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Base:
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add dword [rsp], @LongMode - Base; offset for far retf, seg is the 1st arg
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mov ecx, MSR_EFER
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rdmsr
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or ah, 1 ; enable LME
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wrmsr
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mov rbx, cr0
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or ebx, 0x80010023 ; enable paging + WP + NE + MP + PE
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mov cr0, rbx
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retf
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@LongMode: ; long mode (64-bit code) starts here
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mov rax, strict qword 0 ; mov rax, ASM_PFX(gSmiHandlerIdtr)
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SmiHandlerIdtrAbsAddr:
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lidt [rax]
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lea ebx, [rdi + DSC_OFFSET]
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mov ax, [rbx + DSC_DS]
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mov ds, eax
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mov ax, [rbx + DSC_OTHERSEG]
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mov es, eax
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mov fs, eax
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mov gs, eax
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mov ax, [rbx + DSC_SS]
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mov ss, eax
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mov rax, strict qword 0 ; mov rax, _SmiHandler
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_SmiHandlerAbsAddr:
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jmp rax
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_SmiHandler:
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mov rbx, [rsp + 0x8] ; rcx <- CpuIndex
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;
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; Save FP registers
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;
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sub rsp, 0x200
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DB 0x48 ; FXSAVE64
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fxsave [rsp]
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add rsp, -0x20
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mov rcx, rbx
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call ASM_PFX(CpuSmmDebugEntry)
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mov rcx, rbx
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call ASM_PFX(SmiRendezvous)
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mov rcx, rbx
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call ASM_PFX(CpuSmmDebugExit)
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add rsp, 0x20
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;
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; Restore FP registers
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;
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DB 0x48 ; FXRSTOR64
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fxrstor [rsp]
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add rsp, 0x200
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lea rax, [ASM_PFX(mXdSupported)]
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mov al, [rax]
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cmp al, 0
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jz .1
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pop rdx ; get saved MSR_IA32_MISC_ENABLE[63-32]
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test edx, BIT2
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jz .1
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mov ecx, MSR_IA32_MISC_ENABLE
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rdmsr
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or dx, BIT2 ; set XD Disable bit if it was set before entering into SMM
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wrmsr
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.1:
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rsm
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ASM_PFX(gcSmiHandlerSize) DW $ - _SmiEntryPoint
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global ASM_PFX(PiSmmCpuSmiEntryFixupAddress)
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ASM_PFX(PiSmmCpuSmiEntryFixupAddress):
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lea rax, [ASM_PFX(gSmiHandlerIdtr)]
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lea rcx, [SmiHandlerIdtrAbsAddr]
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mov qword [rcx - 8], rax
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lea rax, [_SmiHandler]
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lea rcx, [_SmiHandlerAbsAddr]
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mov qword [rcx - 8], rax
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ret
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