Enabled 4G+ memory in thunk.

git-svn-id: https://edk2.svn.sourceforge.net/svnroot/edk2/trunk/edk2@1957 6f19259b-4bc3-4df7-8a09-765794883524

1 files changed, 22 insertions, 16 deletions

diff --git a/MdePkg/Library/BaseLib/X64/Thunk16.asm b/MdePkg/Library/BaseLib/X64/Thunk16.asm
index 631b0fd1e1..b77ba68042 100644
--- a/MdePkg/Library/BaseLib/X64/Thunk16.asm
+++ b/MdePkg/Library/BaseLib/X64/Thunk16.asm
@@ -100,6 +100,11 @@ _ThunkAttr  DD      ?
     mov     ebx, (IA32_REGS ptr [rsi - sizeof (IA32_REGS)])._EIP

     shl     ax, 4                       ; shl eax, 4

     add     bp, ax                      ; add ebp, eax

+    mov     ax, cs

+    shl     ax, 4

+    lea     ax, [eax + ebx + (@64BitCode - @Base)]

+    DB      2eh                         ; cs:

+    mov     [rdi + (@64Eip - @Base)], ax

     DB      66h, 0b8h                   ; mov eax, imm32

 SavedCr4    DD      ?

     mov     cr4, rax

@@ -113,13 +118,13 @@ SavedCr4    DD      ?
     DB      66h, 0b8h                   ; mov eax, imm32

 SavedCr0    DD      ?

     mov     cr0, rax

-    DB      0b8h                        ; mov ax, imm16

-SavedSs     DW      ?

-    mov     ss, eax

-    DB      66h, 0bch                   ; mov esp, imm32

-SavedEsp    DD      ?

-    DB      66h

-    retf                                ; return to protected mode

+    DB      66h, 0eah                   ; jmp far cs:@64Bit

+@64Eip      DD      ?

+SavedCs     DW      ?

+@64BitCode:

+    DB      48h, 0b8h                   ; mov rax, imm64

+SavedRip    DQ      ?

+    jmp     rax                         ; return to caller

 _BackFromUserCode   ENDP

 

 _EntryPoint DD      _ToUserCode - m16Start

@@ -147,7 +152,7 @@ _ToUserCode PROC
     wrmsr

     mov     cr4, rbp

     mov     ss, esi                     ; set up 16-bit stack segment

-    xchg    sp, bx                      ; set up 16-bit stack pointer

+    mov     sp, bx                      ; set up 16-bit stack pointer

     DB      66h

     call    @Base                       ; push eip

 @Base:

@@ -157,11 +162,6 @@ _ToUserCode PROC
     push    rax

     retf

 @RealMode:

-    DB      6ah, DATA32

-    DB      2eh                         ; cs:

-    pop     [rsi + (SavedSs - @Base)]

-    DB      2eh                         ; cs:

-    mov     [rsi + (SavedEsp - @Base)], bx

     DB      66h, 2eh                    ; CS and operand size override

     lidt    fword ptr [rsi + (_16Idtr - @Base)]

     DB      66h, 61h                    ; popad

@@ -232,8 +232,7 @@ InternalAsmThunk16  PROC    USES    rbp rbx rsi rdi
     mov     eax, edx                    ; eax <- transition code address

     and     edx, 0fh

     shl     eax, 12

-    lea     edx, [rdx + (_BackFromUserCode - m16Start)]

-    mov     ax, dx

+    lea     ax, [rdx + (_BackFromUserCode - m16Start)]

     stosd                               ; [edi] <- return address of user code

     sgdt    fword ptr [rcx + (SavedGdt - SavedCr4)]

     sidt    fword ptr [rsp + 38h]       ; save IDT stack in argument space

@@ -250,7 +249,14 @@ InternalAsmThunk16  PROC    USES    rbp rbx rsi rdi
     mov     ss, edx

     pushfq

     lea     edx, [rdx + DATA16 - DATA32]

-    call    fword ptr [rcx + (_EntryPoint - SavedCr4)]

+    lea     r8, @RetFromRealMode

+    mov     [rcx + (SavedRip - SavedCr4)], r8

+    mov     r8d, cs

+    mov     [rcx + (SavedCs - SavedCr4)], r8w

+    mov     r8, rsp

+    jmp     fword ptr [rcx + (_EntryPoint - SavedCr4)]

+@RetFromRealMode:

+    mov     rsp, r8

     popfq

     lidt    fword ptr [rsp + 38h]       ; restore protected mode IDTR

     lea     eax, [rbp - sizeof (IA32_REGS)]