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## @file
# Code template of the SMI handler for a particular processor
#
# Copyright (c) 2009 - 2015, 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
#
##
ASM_GLOBAL ASM_PFX(gcSmiHandlerTemplate)
ASM_GLOBAL ASM_PFX(gcSmiHandlerSize)
ASM_GLOBAL ASM_PFX(gSmiCr3)
ASM_GLOBAL ASM_PFX(gcSmiHandlerOffset)
ASM_GLOBAL ASM_PFX(gSmiStack)
ASM_GLOBAL ASM_PFX(gSmbase)
ASM_GLOBAL ASM_PFX(FeaturePcdGet (PcdCpuSmmDebug))
ASM_GLOBAL ASM_PFX(FeaturePcdGet (PcdCpuSmmStackGuard))
.equ DSC_OFFSET, 0xfb00
.equ DSC_GDTPTR, 0x30
.equ DSC_GDTSIZ, 0x38
.equ DSC_CS, 14
.equ DSC_DS, 16
.equ DSC_SS, 18
.equ DSC_OTHERSEG, 20
.equ MSR_DR6, 0x0c05
.equ MSR_DR7, 0x0c06
.equ TSS_SEGMENT, 0x40
.data
ASM_PFX(gcSmiHandlerOffset): .word _SmiHandler - _SmiEntryPoint + 0x8000
.text
ASM_PFX(gcSmiHandlerTemplate):
_SmiEntryPoint:
.byte 0xbb # mov bx, imm16
.word _GdtDesc - _SmiEntryPoint + 0x8000
.byte 0x2e,0xa1 # mov ax, cs:[offset16]
.word DSC_OFFSET + DSC_GDTSIZ
decl %eax
movl %eax, %cs:(%edi) # mov cs:[bx], ax
.byte 0x66,0x2e,0xa1 # mov eax, cs:[offset16]
.word DSC_OFFSET + DSC_GDTPTR
movw %ax, %cs:2(%edi)
movw %ax, %bp # ebp = GDT base
.byte 0x66
lgdt %cs:(%edi)
.byte 0x66,0xb8 # mov eax, imm32
ASM_PFX(gSmiCr3): .space 4
movl %eax, %cr3
.byte 0x66
movl $0x668,%eax # as cr4.PGE is not set here, refresh cr3
movl %eax, %cr4 # in PreModifyMtrrs() to flush TLB.
.byte 0x2e,0xa1 # mov ax, cs:[offset16]
.word DSC_OFFSET + DSC_CS
movl %eax, %cs:-2(%edi)
.byte 0x66, 0xbf # mov edi, SMBASE
ASM_PFX(gSmbase): .space 4
.byte 0x67
lea ((Start32bit - _SmiEntryPoint) + 0x8000)(%edi), %ax
movw %ax, %cs:-6(%edi)
movl %cr0, %ebx
.byte 0x66
andl $0x9ffafff3, %ebx
.byte 0x66
orl $0x80000023, %ebx
movl %ebx, %cr0
.byte 0x66,0xea
.space 4
.space 2
_GdtDesc: .space 4
.space 2
Start32bit:
leal DSC_OFFSET(%edi),%ebx
movw DSC_DS(%ebx),%ax
movl %eax,%ds
movw DSC_OTHERSEG(%ebx),%ax
movl %eax,%es
movl %eax,%fs
movl %eax,%gs
movw DSC_SS(%ebx),%ax
movl %eax,%ss
cmpb $0, ASM_PFX(FeaturePcdGet (PcdCpuSmmStackGuard))
jz L5
# Load TSS
movb $0x89, (TSS_SEGMENT + 5)(%ebp) # clear busy flag
movl $TSS_SEGMENT, %eax
ltrw %ax
L5:
# jmp _SmiHandler # instruction is not needed
_SmiHandler:
.byte 0xbc # mov esp, imm32
ASM_PFX(gSmiStack): .space 4
cmpb $0, ASM_PFX(FeaturePcdGet (PcdCpuSmmDebug))
jz L3
jz L6
L6:
call L1
L1:
popl %ebp
movl $0x80000001, %eax
cpuid
btl $29, %edx # check cpuid to identify X64 or IA32
leal (0x7fc8 - (L1 - _SmiEntryPoint))(%ebp), %edi
leal 4(%edi), %esi
jnc L2
addl $4, %esi
L2:
movl (%esi), %ecx
movl (%edi), %edx
L7:
movl %ecx, %dr6
movl %edx, %dr7 # restore DR6 & DR7 before running C code
L3:
pushl (%esp)
movl $ASM_PFX(SmiRendezvous), %eax
call *%eax
popl %ecx
cmpb $0, ASM_PFX(FeaturePcdGet (PcdCpuSmmDebug))
jz L4
movl %dr6, %ecx
movl %dr7, %edx
movl %ecx, (%esi)
movl %edx, (%edi)
L4:
rsm
ASM_PFX(gcSmiHandlerSize): .word . - _SmiEntryPoint
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