1. Fixed bug in FlushCacheLine.asm, added return value

[mirror_edk2.git] / MdePkg / Library / BaseLib / Ia32 / EnablePaging64.asm

diff --git a/MdePkg/Library/BaseLib/Ia32/EnablePaging64.asm b/MdePkg/Library/BaseLib/Ia32/EnablePaging64.asm
index 6c9b0ea76bca8a44de6914f218b73ca1b13c4975..97d859e966f5add11408dda8bc04463e7ed07505 100644 (file)
--- a/MdePkg/Library/BaseLib/Ia32/EnablePaging64.asm
+++ b/MdePkg/Library/BaseLib/Ia32/EnablePaging64.asm
@@ -26,9 +26,13 @@
     .code\r
 \r
 InternalX86EnablePaging64 PROC\r
-    cli\r
-    mov     [esp], @F                   ; offset for far retf\r
-    mov     eax, cr4\r
+    cli
+\r
+    mov     ebx, [esp + 4]              ; save CS
+    mov     eax, OFFSET cs_address
+    mov     word ptr [eax], bx          ; Update CS selector for far jump
+\r
+    mov     eax, cr4 \r
     or      al, (1 SHL 5)\r
     mov     cr4, eax                    ; enable PAE\r
     mov     ecx, 0c0000080h\r
@@ -37,19 +41,30 @@ InternalX86EnablePaging64 PROC
     wrmsr\r
     mov     eax, cr0\r
     bts     eax, 31\r
-    mov     cr0, eax                    ; enable paging\r
-    retf\r
-@@:                                     ; long mode starts here\r
-    DB      67h, 48h\r
-    mov     ebx, [esp]                  ; mov rbx, [esp]\r
+    mov     cr0, eax                    ; enable paging
+    retf
+    jmp     go_to_long_mode
+go_to_long_mode:
+
+    ;
+    ; This is the next instruction after enabling paging.  Jump to long mode
+    ;
+    db      067h
+    db      0eah                        ;   Far Jump Offset:Selector to reload CS
+    dd      OFFSET in_long_mode         ;   Offset is ensuing instruction boundary
+cs_address:
+    dw      0h                          ;   CS selector will be updated at runtime 
+\r
+in_long_mode:                           ; now in long mode
     DB      67h, 48h\r
-    mov     ecx, [esp + 8]              ; mov rcx, [esp + 8]\r
+    mov     ebx, [esp + 8]              ; mov rbx, [esp]\r
+    DB      67h, 48h\r                   
+    mov     ecx, [esp + 10h]            ; mov rcx, [esp + 8]\r
     DB      67h, 48h\r
-    mov     edx, [esp + 10h]            ; mov rdx, [esp + 10h]\r
+    mov     edx, [esp + 18h]            ; mov rdx, [esp + 10h]\r
     DB      67h, 48h\r
-    mov     esp, [esp + 18h]            ; mov rsp, [esp + 18h]\r
+    mov     esp, [esp + 20h]            ; mov rsp, [esp + 18h]\r
     DB      48h\r
-    add     esp, -20h                   ; add rsp, -20h\r
     call    ebx                         ; call rbx\r
     jmp     $\r
 InternalX86EnablePaging64 ENDP\r