#------------------------------------------------------------------------------ # # Copyright (c) 2009 - 2016, Intel Corporation. All rights reserved.
# 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.S # # Abstract: # # Code template of the SMI handler for a particular processor # #------------------------------------------------------------------------------ ASM_GLOBAL ASM_PFX(gcSmiHandlerTemplate) ASM_GLOBAL ASM_PFX(gcSmiHandlerSize) ASM_GLOBAL ASM_PFX(gSmiCr3) ASM_GLOBAL ASM_PFX(gSmiStack) ASM_GLOBAL ASM_PFX(gSmbase) ASM_GLOBAL ASM_PFX(mXdSupported) ASM_GLOBAL ASM_PFX(gSmiHandlerIdtr) .equ MSR_IA32_MISC_ENABLE, 0x1A0 .equ MSR_EFER, 0xc0000080 .equ MSR_EFER_XD, 0x800 # # Constants relating to PROCESSOR_SMM_DESCRIPTOR # .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 # # Constants relating to CPU State Save Area # .equ SSM_DR6, 0xffd0 .equ SSM_DR7, 0xffc8 .equ PROTECT_MODE_CS, 0x08 .equ PROTECT_MODE_DS, 0x20 .equ LONG_MODE_CS, 0x38 .equ TSS_SEGMENT, 0x40 .equ GDT_SIZE, 0x50 .text ASM_PFX(gcSmiHandlerTemplate): _SmiEntryPoint: # # The encoding of BX in 16-bit addressing mode is the same as of RDI in 64- # bit addressing mode. And that coincidence has been used in the following # "64-bit like" 16-bit code. Be aware that once RDI is referenced as a # base address register, it is actually BX that is referenced. # .byte 0xbb # mov bx, imm16 .word _GdtDesc - _SmiEntryPoint + 0x8000 # # fix GDT descriptor # .byte 0x2e,0xa1 # mov ax, cs:[offset16] .word DSC_OFFSET + DSC_GDTSIZ .byte 0x48 # dec ax .byte 0x2e movl %eax, (%rdi) # mov cs:[bx], ax .byte 0x66,0x2e,0xa1 # mov eax, cs:[offset16] .word DSC_OFFSET + DSC_GDTPTR .byte 0x2e movw %ax, 2(%rdi) .byte 0x66,0x2e lgdt (%rdi) # # Patch ProtectedMode Segment # .byte 0xb8 .word PROTECT_MODE_CS .byte 0x2e movl %eax, -2(%rdi) # # Patch ProtectedMode entry # .byte 0x66, 0xbf # mov edi, SMBASE ASM_PFX(gSmbase): .space 4 lea ((ProtectedMode - _SmiEntryPoint) + 0x8000)(%edi), %ax .byte 0x2e movw %ax, -6(%rdi) # # Switch into ProtectedMode # movq %cr0, %rbx .byte 0x66 andl $0x9ffafff3, %ebx .byte 0x66 orl $0x00000023, %ebx movq %rbx, %cr0 .byte 0x66, 0xea .space 6 _GdtDesc: .space 6 ProtectedMode: movw $PROTECT_MODE_DS, %ax movl %eax, %ds movl %eax, %es movl %eax, %fs movl %eax, %gs movl %eax, %ss .byte 0xbc # mov esp, imm32 ASM_PFX(gSmiStack): .space 4 jmp ProtFlatMode ProtFlatMode: .byte 0xb8 ASM_PFX(gSmiCr3): .space 4 movq %rax, %cr3 movl $0x668,%eax # as cr4.PGE is not set here, refresh cr3 movq %rax, %cr4 # in PreModifyMtrrs() to flush TLB. # Load TSS subl $8, %esp # reserve room in stack sgdt (%rsp) movl 2(%rsp), %eax # eax = GDT base addl $8, %esp movb $0x89, %dl movb %dl, (TSS_SEGMENT + 5)(%rax) # clear busy flag movl $TSS_SEGMENT, %eax ltr %ax # enable NXE if supported .byte 0xb0 # mov al, imm8 ASM_PFX(mXdSupported): .byte 1 cmpb $0, %al jz SkipNxe # # Check XD disable bit # movl $MSR_IA32_MISC_ENABLE, %ecx rdmsr subl $4, %esp pushq %rdx # save MSR_IA32_MISC_ENABLE[63-32] testl $BIT2, %edx # MSR_IA32_MISC_ENABLE[34] jz L13 andw $0x0FFFB, %dx # clear XD Disable bit if it is set wrmsr L13: movl $MSR_EFER, %ecx rdmsr orw $MSR_EFER_XD,%ax # enable NXE wrmsr jmp NxeDone SkipNxe: subl $8, %esp NxeDone: # # Switch to LongMode # pushq $LONG_MODE_CS # push cs hardcore here call Base # push return address for retf later Base: addl $(LongMode - Base), (%rsp) # offset for far retf, seg is the 1st arg movl $MSR_EFER, %ecx rdmsr orb $1,%ah # enable LME wrmsr movq %cr0, %rbx orl $0x080010023, %ebx # enable paging + WP + NE + MP + PE movq %rbx, %cr0 retf LongMode: # long mode (64-bit code) starts here movabsq $ASM_PFX(gSmiHandlerIdtr), %rax lidt (%rax) lea (DSC_OFFSET)(%rdi), %ebx movw DSC_DS(%rbx), %ax movl %eax,%ds movw DSC_OTHERSEG(%rbx), %ax movl %eax,%es movl %eax,%fs movl %eax,%gs movw DSC_SS(%rbx), %ax movl %eax,%ss # jmp _SmiHandler ; instruction is not needed _SmiHandler: movq 8(%rsp), %rbx # Save FP registers subq $0x200, %rsp .byte 0x48 # FXSAVE64 fxsave (%rsp) addq $-0x20, %rsp movq %rbx, %rcx movabsq $ASM_PFX(CpuSmmDebugEntry), %rax call *%rax movq %rbx, %rcx movabsq $ASM_PFX(SmiRendezvous), %rax call *%rax movq %rbx, %rcx movabsq $ASM_PFX(CpuSmmDebugExit), %rax call *%rax addq $0x20, %rsp # # Restore FP registers # .byte 0x48 # FXRSTOR64 fxrstor (%rsp) addq $0x200, %rsp movabsq $ASM_PFX(mXdSupported), %rax movb (%rax), %al cmpb $0, %al jz L16 popq %rdx # get saved MSR_IA32_MISC_ENABLE[63-32] testl $BIT2, %edx jz L16 movl $MSR_IA32_MISC_ENABLE, %ecx rdmsr orw $BIT2, %dx # set XD Disable bit if it was set before entering into SMM wrmsr L16: rsm ASM_PFX(gcSmiHandlerSize): .word . - _SmiEntryPoint