Changeset 59259 in vbox for trunk/src/VBox/ValidationKit/bootsectors/bs3kit/bs3-mode-SwitchToLM64.asm

Timestamp:

Jan 6, 2016 2:53:27 AM (9 years ago)

Author:

vboxsync

Message:

bs3kit: More IDT handling (mainly 32-bit).

File:

• trunk/src/VBox/ValidationKit/bootsectors/bs3kit/bs3-mode-SwitchToLM64.asm (modified) (2 diffs)

trunk/src/VBox/ValidationKit/bootsectors/bs3kit/bs3-mode-SwitchToLM64.asm

@@ -29 +29 @@
 
 ;;
-; Switch to PAE paged protected mode from any other mode.
+; Switch to 64-bit long mode from any other mode.
 ;
 ; @cproto   BS3_DECL(void) Bs3SwitchToLM64(void);
 ;
-; @uses     Nothing (except high 32-bit register parts), upper part of ESP is
-;           cleared if caller is in 16-bit mode.
+; @uses     Nothing (except possibly high 32-bit and/or upper 64-bit register parts).
 ;
-; @remarks  Obviously returns to 32-bit mode, even if the caller was
-;           in 16-bit or 64-bit mode.  It doesn't not preserve the callers
-;           ring, but instead changes to ring-0.
+; @remarks  Obviously returns to 64-bit mode, even if the caller was in 16-bit
+;           or 32-bit mode.  It doesn't not preserve the callers ring, but
+;           instead changes to ring-0.
 ;
 BS3_PROC_BEGIN_MODE Bs3SwitchToLM64
@@ -52 +51 @@
 
 %else
- %if TMPL_BITS == 16
-        push    word 0                  ; save space for extending the return value.
- %endif
+        ;
+        ; Switch to LM32 and then switch to 64-bits (IDT & TSS are the same for
+        ; LM16, LM32 and LM64, unlike the rest).
+        ;
+        ; (The long mode switching code is going via 32-bit protected mode, so
+        ; Bs3SwitchToLM32 contains the actual code for switching to avoid
+        ; unnecessary 32-bit -> 64-bit -> 32-bit trips.)
+        ;
+        extern  TMPL_NM(Bs3SwitchToLM32)
+        call    TMPL_NM(Bs3SwitchToLM32)
+        BS3_SET_BITS 32
 
-        ;
-        ; Switch to 32-bit protected mode (for identify mapped pages).
-        ;
-        extern  TMPL_NM(Bs3SwitchToPE32)
-        call    TMPL_NM(Bs3SwitchToPE32)
-        BS3_SET_BITS 32
- %if TMPL_BITS == 16
-        jmp     .thirty_two_bit_segment
-BS3_BEGIN_TEXT32
-.thirty_two_bit_segment:
- %endif
-
-        push    eax
-        push    ecx
-        push    edx
-        pushfd
-
-        ;
-        ; Make sure both PAE and PSE are enabled (requires pentium pro).
-        ;
-        mov     eax, cr4
-        mov     ecx, eax
-        or      eax, X86_CR4_PAE | X86_CR4_PSE
-        cmp     eax, ecx
-        je      .cr4_is_fine
-        mov     cr4, eax
-.cr4_is_fine:
-
-        ;
-        ; Get the page directory (returned in eax).
-        ; Will lazy init page tables.
-        ;
-        extern NAME(Bs3PagingGetRootForLM64_pe32)
-        call   NAME(Bs3PagingGetRootForLM64_pe32)
-
-        cli
-        mov     cr3, eax
-
-        ;
-        ; Enable long mode in EFER.
-        ;
-        mov     ecx, MSR_K6_EFER
-        rdmsr
-        or      eax, MSR_K6_EFER_LME
-        wrmsr
-
-        ;
-        ; Enable paging and thereby activating LM64.
-        ;
-BS3_EXTERN_SYSTEM16 Bs3Lgdt_Gdt
-BS3_BEGIN_TEXT32
-        mov     eax, cr0
-        or      eax, X86_CR0_PG
-        mov     cr0, eax
-        jmp     .in_lm32
-.in_lm32:
-
-        ;
-        ; Call rountine for doing mode specific setups.
-        ;
-        extern  NAME(Bs3EnteredMode_lm32)
-        call    NAME(Bs3EnteredMode_lm32)
-
-        ;
-        ; Restore ecx, eax and flags (IF).
-        ;
- %if TMPL_BITS == 16
-        movzx   eax, word [esp + 16 + 2] ; Load return address.
-        add     eax, BS3_ADDR_BS3TEXT16  ; Convert it to a flat address.
-        mov     [esp + 16], eax          ; Store it in the place right for 32-bit returns.
- %endif
-        popfd
-        pop     edx
-        pop     ecx
-        pop     eax
-
-        ;
-        ; Now go to 32-bit mode.
-        ;
-        extern  NAME(Bs3SwitchTo64Bit_c32)
-        jmp     NAME(Bs3SwitchTo64Bit_c32)
-
- %if TMPL_BITS != 32
-TMPL_BEGIN_TEXT
- %endif
+        extern  _Bs3SwitchTo64Bit_c32
+        jmp     _Bs3SwitchTo64Bit_c32
 %endif
 BS3_PROC_END_MODE   Bs3SwitchToLM64