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|
;------------------------------------------------------------------------------ ;
; Copyright (c) 2016 - 2018, 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:
;
; SmiEntry.nasm
;
; Abstract:
;
; Code template of the SMI handler for a particular processor
;
;-------------------------------------------------------------------------------
;
; Variables referrenced by C code
;
%define MSR_IA32_MISC_ENABLE 0x1A0
%define MSR_EFER 0xc0000080
%define MSR_EFER_XD 0x800
;
; Constants relating to PROCESSOR_SMM_DESCRIPTOR
;
%define DSC_OFFSET 0xfb00
%define DSC_GDTPTR 0x30
%define DSC_GDTSIZ 0x38
%define DSC_CS 14
%define DSC_DS 16
%define DSC_SS 18
%define DSC_OTHERSEG 20
;
; Constants relating to CPU State Save Area
;
%define SSM_DR6 0xffd0
%define SSM_DR7 0xffc8
%define PROTECT_MODE_CS 0x8
%define PROTECT_MODE_DS 0x20
%define LONG_MODE_CS 0x38
%define TSS_SEGMENT 0x40
%define GDT_SIZE 0x50
extern ASM_PFX(SmiRendezvous)
extern ASM_PFX(gSmiHandlerIdtr)
extern ASM_PFX(CpuSmmDebugEntry)
extern ASM_PFX(CpuSmmDebugExit)
global ASM_PFX(gPatchSmbase)
global ASM_PFX(mXdSupported)
global ASM_PFX(gSmiStack)
global ASM_PFX(gSmiCr3)
global ASM_PFX(gcSmiHandlerTemplate)
global ASM_PFX(gcSmiHandlerSize)
DEFAULT REL
SECTION .text
BITS 16
ASM_PFX(gcSmiHandlerTemplate):
_SmiEntryPoint:
mov bx, _GdtDesc - _SmiEntryPoint + 0x8000
mov ax,[cs:DSC_OFFSET + DSC_GDTSIZ]
dec ax
mov [cs:bx], ax
mov eax, [cs:DSC_OFFSET + DSC_GDTPTR]
mov [cs:bx + 2], eax
o32 lgdt [cs:bx] ; lgdt fword ptr cs:[bx]
mov ax, PROTECT_MODE_CS
mov [cs:bx-0x2],ax
mov edi, strict dword 0 ; source operand will be patched
ASM_PFX(gPatchSmbase):
lea eax, [edi + (@ProtectedMode - _SmiEntryPoint) + 0x8000]
mov [cs:bx-0x6],eax
mov ebx, cr0
and ebx, 0x9ffafff3
or ebx, 0x23
mov cr0, ebx
jmp dword 0x0:0x0
_GdtDesc:
DW 0
DD 0
BITS 32
@ProtectedMode:
mov ax, PROTECT_MODE_DS
o16 mov ds, ax
o16 mov es, ax
o16 mov fs, ax
o16 mov gs, ax
o16 mov ss, ax
DB 0xbc ; mov esp, imm32
ASM_PFX(gSmiStack): DD 0
jmp ProtFlatMode
BITS 64
ProtFlatMode:
DB 0xb8 ; mov eax, offset gSmiCr3
ASM_PFX(gSmiCr3): DD 0
mov cr3, rax
mov eax, 0x668 ; as cr4.PGE is not set here, refresh cr3
mov cr4, rax ; in PreModifyMtrrs() to flush TLB.
; Load TSS
sub esp, 8 ; reserve room in stack
sgdt [rsp]
mov eax, [rsp + 2] ; eax = GDT base
add esp, 8
mov dl, 0x89
mov [rax + TSS_SEGMENT + 5], dl ; clear busy flag
mov eax, TSS_SEGMENT
ltr ax
; enable NXE if supported
DB 0xb0 ; mov al, imm8
ASM_PFX(mXdSupported): DB 1
cmp al, 0
jz @SkipXd
;
; Check XD disable bit
;
mov ecx, MSR_IA32_MISC_ENABLE
rdmsr
sub esp, 4
push rdx ; save MSR_IA32_MISC_ENABLE[63-32]
test edx, BIT2 ; MSR_IA32_MISC_ENABLE[34]
jz .0
and dx, 0xFFFB ; clear XD Disable bit if it is set
wrmsr
.0:
mov ecx, MSR_EFER
rdmsr
or ax, MSR_EFER_XD ; enable NXE
wrmsr
jmp @XdDone
@SkipXd:
sub esp, 8
@XdDone:
; Switch into @LongMode
push LONG_MODE_CS ; push cs hardcore here
call Base ; push return address for retf later
Base:
add dword [rsp], @LongMode - Base; offset for far retf, seg is the 1st arg
mov ecx, MSR_EFER
rdmsr
or ah, 1 ; enable LME
wrmsr
mov rbx, cr0
or ebx, 0x80010023 ; enable paging + WP + NE + MP + PE
mov cr0, rbx
retf
@LongMode: ; long mode (64-bit code) starts here
mov rax, strict qword 0 ; mov rax, ASM_PFX(gSmiHandlerIdtr)
SmiHandlerIdtrAbsAddr:
lidt [rax]
lea ebx, [rdi + DSC_OFFSET]
mov ax, [rbx + DSC_DS]
mov ds, eax
mov ax, [rbx + DSC_OTHERSEG]
mov es, eax
mov fs, eax
mov gs, eax
mov ax, [rbx + DSC_SS]
mov ss, eax
mov rax, strict qword 0 ; mov rax, _SmiHandler
_SmiHandlerAbsAddr:
jmp rax
_SmiHandler:
mov rbx, [rsp + 0x8] ; rcx <- CpuIndex
;
; Save FP registers
;
sub rsp, 0x200
DB 0x48 ; FXSAVE64
fxsave [rsp]
add rsp, -0x20
mov rcx, rbx
call ASM_PFX(CpuSmmDebugEntry)
mov rcx, rbx
call ASM_PFX(SmiRendezvous)
mov rcx, rbx
call ASM_PFX(CpuSmmDebugExit)
add rsp, 0x20
;
; Restore FP registers
;
DB 0x48 ; FXRSTOR64
fxrstor [rsp]
add rsp, 0x200
lea rax, [ASM_PFX(mXdSupported)]
mov al, [rax]
cmp al, 0
jz .1
pop rdx ; get saved MSR_IA32_MISC_ENABLE[63-32]
test edx, BIT2
jz .1
mov ecx, MSR_IA32_MISC_ENABLE
rdmsr
or dx, BIT2 ; set XD Disable bit if it was set before entering into SMM
wrmsr
.1:
rsm
ASM_PFX(gcSmiHandlerSize) DW $ - _SmiEntryPoint
global ASM_PFX(PiSmmCpuSmiEntryFixupAddress)
ASM_PFX(PiSmmCpuSmiEntryFixupAddress):
lea rax, [ASM_PFX(gSmiHandlerIdtr)]
lea rcx, [SmiHandlerIdtrAbsAddr]
mov qword [rcx - 8], rax
lea rax, [_SmiHandler]
lea rcx, [_SmiHandlerAbsAddr]
mov qword [rcx - 8], rax
ret
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