mirror of https://github.com/acidanthera/audk.git
Save segment registers on stack in case the thunk code assembly calls CF9 soft reset and the x64 registers get cleared.
git-svn-id: https://edk2.svn.sourceforge.net/svnroot/edk2/trunk/edk2@8123 6f19259b-4bc3-4df7-8a09-765794883524
This commit is contained in:
qhuang8
parent
14ca06407d
commit
0fe43214e3
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@ -139,7 +139,10 @@ SavedCr0: .space 4
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L_64Eip: .space 4
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SavedCs: .space 2
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L_64BitCode:
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movq %r8, %rsp
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.byte 0x90
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.byte 0x67,0xbc # mov esp, imm32
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SavedSp: .space 4 # restore stack
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nop
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ret
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_EntryPoint: .long ASM_PFX(ToUserCode) - ASM_PFX(m16Start)
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@ -227,7 +230,6 @@ ASM_PFX(_32Data):
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# IN OUT VOID *Transition
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# );
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#------------------------------------------------------------------------------
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# MISMATCH: "InternalAsmThunk16 PROC USES rbp rbx rsi rdi"
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.globl ASM_PFX(InternalAsmThunk16)
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ASM_PFX(InternalAsmThunk16):
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@ -236,9 +238,13 @@ ASM_PFX(InternalAsmThunk16):
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pushq %rsi
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pushq %rdi
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movl %ds, %r10d # r9 ~ r11 are not accessible in 16-bit
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movl %es, %r11d # so use them for saving seg registers
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movl %ss, %r9d
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movq %ds, %rbx
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pushq %rbx # Save ds segment register on the stack
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movq %es, %rbx
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pushq %rbx # Save es segment register on the stack
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movq %ss, %rbx
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pushq %rbx # Save ss segment register on the stack
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.byte 0x0f, 0xa0 #push fs
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.byte 0x0f, 0xa8 #push gs
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movq %rcx, %rsi
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@ -259,7 +265,7 @@ ASM_PFX(InternalAsmThunk16):
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lea (_BackFromUserCode - ASM_PFX(m16Start))(%rdx), %ax
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stosl # [edi] <- return address of user code
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sgdt (SavedGdt - SavedCr4)(%rcx)
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sidt 0x38(%rsp)
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sidt 0x50(%rsp)
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movq %cr0, %rax
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movl %eax, (SavedCr0 - SavedCr4)(%rcx)
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andl $0x7ffffffe,%eax # clear PE, PG bits
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@ -277,18 +283,22 @@ ASM_PFX(InternalAsmThunk16):
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pushq %r8
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movl %cs, %r8d
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movw %r8w, (SavedCs - SavedCr4)(%rcx)
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movq %rsp, %r8
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movl %esp, (SavedSp - SavedCr4)(%rcx)
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.byte 0xff, 0x69 # jmp (_EntryPoint - SavedCr4)(%rcx)
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.byte _EntryPoint - SavedCr4
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L_RetFromRealMode:
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popfq
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lidt 0x38(%rsp)
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lidt 0x50(%rsp)
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lea -IA32_REGS_SIZE(%rbp), %eax
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.byte 0x0f, 0xa9 # pop gs
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.byte 0x0f, 0xa1 # pop fs
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movl %r9d, %ss
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movl %r11d, %es
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movl %r10d, %ds
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popq %rbx
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movq %rbx, %ss
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popq %rbx
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movq %rbx, %es
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popq %rbx
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movq %rbx, %ds
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popq %rdi
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popq %rsi
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@ -140,7 +140,10 @@ SavedCr0 DD ?
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@64Eip DD ?
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SavedCs DW ?
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@64BitCode:
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mov rsp, r8 ; restore stack
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db 090h
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db 067h, 0bch ; mov esp, imm32
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SavedSp DD ? ; restore stack
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nop
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ret
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_BackFromUserCode ENDP
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@ -230,9 +233,13 @@ GDT_SIZE = $ - _NullSeg
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; );
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;------------------------------------------------------------------------------
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InternalAsmThunk16 PROC USES rbp rbx rsi rdi
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mov r10d, ds ; r9 ~ r11 are not accessible in 16-bit
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mov r11d, es ; so use them for saving seg registers
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mov r9d, ss
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mov rbx, ds
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push rbx ; Save ds segment register on the stack
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mov rbx, es
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push rbx ; Save es segment register on the stack
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mov rbx, ss
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push rbx ; Save ss segment register on the stack
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push fs
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push gs
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mov rsi, rcx
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@ -252,7 +259,7 @@ InternalAsmThunk16 PROC USES rbp rbx rsi rdi
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lea ax, [rdx + (_BackFromUserCode - m16Start)] ; offset address
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stosd ; [edi] <- return address of user code
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sgdt fword ptr [rcx + (SavedGdt - SavedCr4)]
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sidt fword ptr [rsp + 38h] ; save IDT stack in argument space
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sidt fword ptr [rsp + 50h] ; save IDT stack in argument space
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mov rax, cr0
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mov [rcx + (SavedCr0 - SavedCr4)], eax
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and eax, 7ffffffeh ; clear PE, PG bits
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@ -270,17 +277,20 @@ InternalAsmThunk16 PROC USES rbp rbx rsi rdi
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push r8
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mov r8d, cs
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mov [rcx + (SavedCs - SavedCr4)], r8w
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mov r8, rsp
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mov [rcx + (SavedSp - SavedCr4)], esp
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jmp fword ptr [rcx + (_EntryPoint - SavedCr4)]
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@RetFromRealMode:
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popfq
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lidt fword ptr [rsp + 38h] ; restore protected mode IDTR
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lidt fword ptr [rsp + 50h] ; restore protected mode IDTR
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lea eax, [rbp - sizeof (IA32_REGS)]
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pop gs
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pop fs
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mov ss, r9d
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mov es, r11d
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mov ds, r10d
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pop rbx
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mov ss, rbx
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pop rbx
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mov es, rbx
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pop rbx
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mov ds, rbx
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ret
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InternalAsmThunk16 ENDP
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