diff options
author | qhuang8 <qhuang8@6f19259b-4bc3-4df7-8a09-765794883524> | 2009-04-17 07:38:57 +0000 |
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committer | qhuang8 <qhuang8@6f19259b-4bc3-4df7-8a09-765794883524> | 2009-04-17 07:38:57 +0000 |
commit | 0fe43214e33e4276741872a783528d896d82e785 (patch) | |
tree | 538a362c0124d6be88648e62afed8aaac8830400 | |
parent | 14ca06407d7fdeeb9fdaf9bfa5f9163c43776e1e (diff) | |
download | edk2-platforms-0fe43214e33e4276741872a783528d896d82e785.tar.xz |
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
-rw-r--r-- | MdePkg/Library/BaseLib/X64/Thunk16.S | 34 | ||||
-rw-r--r-- | MdePkg/Library/BaseLib/X64/Thunk16.asm | 30 |
2 files changed, 42 insertions, 22 deletions
diff --git a/MdePkg/Library/BaseLib/X64/Thunk16.S b/MdePkg/Library/BaseLib/X64/Thunk16.S index b829685b43..f9770b258c 100644 --- a/MdePkg/Library/BaseLib/X64/Thunk16.S +++ b/MdePkg/Library/BaseLib/X64/Thunk16.S @@ -136,10 +136,13 @@ SavedCr4: .space 4 SavedCr0: .space 4
movq %rax, %cr0
.byte 0x66,0xea # jmp far cs:L_64Bit
-L_64Eip: .space 4
+L_64Eip: .space 4
SavedCs: .space 2
L_64BitCode:
- movq %r8, %rsp
+ .byte 0x90
+ .byte 0x67,0xbc # mov esp, imm32
+SavedSp: .space 4 # restore stack
+ nop
ret
_EntryPoint: .long ASM_PFX(ToUserCode) - ASM_PFX(m16Start)
@@ -227,7 +230,6 @@ ASM_PFX(_32Data): # IN OUT VOID *Transition
# );
#------------------------------------------------------------------------------
-# MISMATCH: "InternalAsmThunk16 PROC USES rbp rbx rsi rdi"
.globl ASM_PFX(InternalAsmThunk16)
ASM_PFX(InternalAsmThunk16):
@@ -236,9 +238,13 @@ ASM_PFX(InternalAsmThunk16): pushq %rsi
pushq %rdi
- movl %ds, %r10d # r9 ~ r11 are not accessible in 16-bit
- movl %es, %r11d # so use them for saving seg registers
- movl %ss, %r9d
+ movq %ds, %rbx
+ pushq %rbx # Save ds segment register on the stack
+ movq %es, %rbx
+ pushq %rbx # Save es segment register on the stack
+ movq %ss, %rbx
+ pushq %rbx # Save ss segment register on the stack
+
.byte 0x0f, 0xa0 #push fs
.byte 0x0f, 0xa8 #push gs
movq %rcx, %rsi
@@ -259,7 +265,7 @@ ASM_PFX(InternalAsmThunk16): lea (_BackFromUserCode - ASM_PFX(m16Start))(%rdx), %ax
stosl # [edi] <- return address of user code
sgdt (SavedGdt - SavedCr4)(%rcx)
- sidt 0x38(%rsp)
+ sidt 0x50(%rsp)
movq %cr0, %rax
movl %eax, (SavedCr0 - SavedCr4)(%rcx)
andl $0x7ffffffe,%eax # clear PE, PG bits
@@ -277,18 +283,22 @@ ASM_PFX(InternalAsmThunk16): pushq %r8
movl %cs, %r8d
movw %r8w, (SavedCs - SavedCr4)(%rcx)
- movq %rsp, %r8
+ movl %esp, (SavedSp - SavedCr4)(%rcx)
.byte 0xff, 0x69 # jmp (_EntryPoint - SavedCr4)(%rcx)
.byte _EntryPoint - SavedCr4
L_RetFromRealMode:
popfq
- lidt 0x38(%rsp)
+ lidt 0x50(%rsp)
lea -IA32_REGS_SIZE(%rbp), %eax
.byte 0x0f, 0xa9 # pop gs
.byte 0x0f, 0xa1 # pop fs
- movl %r9d, %ss
- movl %r11d, %es
- movl %r10d, %ds
+
+ popq %rbx + movq %rbx, %ss + popq %rbx + movq %rbx, %es + popq %rbx + movq %rbx, %ds popq %rdi
popq %rsi
diff --git a/MdePkg/Library/BaseLib/X64/Thunk16.asm b/MdePkg/Library/BaseLib/X64/Thunk16.asm index d93af44597..cef63d98e1 100644 --- a/MdePkg/Library/BaseLib/X64/Thunk16.asm +++ b/MdePkg/Library/BaseLib/X64/Thunk16.asm @@ -140,7 +140,10 @@ SavedCr0 DD ? @64Eip DD ?
SavedCs DW ?
@64BitCode:
- mov rsp, r8 ; restore stack
+ db 090h
+ db 067h, 0bch ; mov esp, imm32
+SavedSp DD ? ; restore stack
+ nop
ret
_BackFromUserCode ENDP
@@ -230,9 +233,13 @@ GDT_SIZE = $ - _NullSeg ; );
;------------------------------------------------------------------------------
InternalAsmThunk16 PROC USES rbp rbx rsi rdi
- mov r10d, ds ; r9 ~ r11 are not accessible in 16-bit
- mov r11d, es ; so use them for saving seg registers
- mov r9d, ss
+ mov rbx, ds
+ push rbx ; Save ds segment register on the stack
+ mov rbx, es
+ push rbx ; Save es segment register on the stack
+ mov rbx, ss
+ push rbx ; Save ss segment register on the stack
+
push fs
push gs
mov rsi, rcx
@@ -252,7 +259,7 @@ InternalAsmThunk16 PROC USES rbp rbx rsi rdi lea ax, [rdx + (_BackFromUserCode - m16Start)] ; offset address
stosd ; [edi] <- return address of user code
sgdt fword ptr [rcx + (SavedGdt - SavedCr4)]
- sidt fword ptr [rsp + 38h] ; save IDT stack in argument space
+ sidt fword ptr [rsp + 50h] ; save IDT stack in argument space
mov rax, cr0
mov [rcx + (SavedCr0 - SavedCr4)], eax
and eax, 7ffffffeh ; clear PE, PG bits
@@ -270,17 +277,20 @@ InternalAsmThunk16 PROC USES rbp rbx rsi rdi push r8
mov r8d, cs
mov [rcx + (SavedCs - SavedCr4)], r8w
- mov r8, rsp
+ mov [rcx + (SavedSp - SavedCr4)], esp
jmp fword ptr [rcx + (_EntryPoint - SavedCr4)]
@RetFromRealMode:
popfq
- lidt fword ptr [rsp + 38h] ; restore protected mode IDTR
+ lidt fword ptr [rsp + 50h] ; restore protected mode IDTR
lea eax, [rbp - sizeof (IA32_REGS)]
pop gs
pop fs
- mov ss, r9d
- mov es, r11d
- mov ds, r10d
+ pop rbx
+ mov ss, rbx
+ pop rbx
+ mov es, rbx
+ pop rbx
+ mov ds, rbx
ret
InternalAsmThunk16 ENDP
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