.model flat,C\r
.code\r
\r
+;------------------------------------------------------------------------------\r
+; VOID\r
+; EFIAPI\r
+; InternalX86EnablePaging64 (\r
+; IN UINT16 Cs,\r
+; IN UINT64 EntryPoint,\r
+; IN UINT64 Context1, OPTIONAL\r
+; IN UINT64 Context2, OPTIONAL\r
+; IN UINT64 NewStack\r
+; );\r
+;------------------------------------------------------------------------------\r
InternalX86EnablePaging64 PROC\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
+ cli\r
+ mov [esp], @F ; offset for far retf, seg is the 1st arg\r
+ mov eax, cr4\r
or al, (1 SHL 5)\r
mov cr4, eax ; enable PAE\r
mov ecx, 0c0000080h\r
or ah, 1 ; set LME\r
wrmsr\r
mov eax, cr0\r
- bts eax, 31\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
+ bts eax, 31 ; set PG\r
+ mov cr0, eax ; enable paging\r
+ retf ; topmost 2 dwords hold the address\r
+@@: ; long mode starts here\r
+ DB 67h, 48h ; 32-bit address size, 64-bit operand size\r
+ mov ebx, [esp] ; mov rbx, [esp]\r
DB 67h, 48h\r
- mov ebx, [esp + 8] ; mov rbx, [esp]\r
- DB 67h, 48h\r
- mov ecx, [esp + 10h] ; mov rcx, [esp + 8]\r
+ mov ecx, [esp + 8] ; mov rcx, [esp + 8]\r
DB 67h, 48h\r
- mov edx, [esp + 18h] ; mov rdx, [esp + 10h]\r
+ mov edx, [esp + 10h] ; mov rdx, [esp + 10h]\r
DB 67h, 48h\r
- mov esp, [esp + 20h] ; mov rsp, [esp + 18h]\r
+ mov esp, [esp + 18h] ; mov rsp, [esp + 18h]\r
DB 48h\r
+ add esp, -20h ; add rsp, -20h\r
call ebx ; call rbx\r
- jmp $\r
+ hlt ; no one should get here\r
InternalX86EnablePaging64 ENDP\r
\r
END\r