Changeset 60291 in vbox for trunk/src/VBox/ValidationKit/bootsectors/bs3kit/bs3-mode-SwitchToPP16.asm

Timestamp:

Apr 1, 2016 8:51:29 PM (9 years ago)

Author:

vboxsync

Message:

bs3kit: A bunch of changes to be able to test the effects of a GDT page being read-only or not-present.

• Extended the GDT so we get a whole page to play paging tricks with.
• Added syscall for restoring a context from ring-0 so we can safely get out of bogus test context that aren't in ring-0 (non-standard CS value causing trouble here). Implemented the string print syscall since the restore syscall forced me to sort out pointers.
• Changed most string printers to do more than one char at a time (usually a line) to save context switches (screen priting is done via INT 10h in real mode).
• Test the CS access bit handling during INT XXh.

File:

• trunk/src/VBox/ValidationKit/bootsectors/bs3kit/bs3-mode-SwitchToPP16.asm (modified) (2 diffs)

trunk/src/VBox/ValidationKit/bootsectors/bs3kit/bs3-mode-SwitchToPP16.asm

@@ -49 +49 @@
 BS3_PROC_BEGIN_MODE Bs3SwitchToPP16
 %ifdef TMPL_PP16
+        extern  BS3_CMN_NM(Bs3SwitchToRing0)
+        call    BS3_CMN_NM(Bs3SwitchToRing0)
+        push    ax
+        mov     ax, BS3_SEL_R0_DS16
+        mov     ds, ax
+        mov     es, ax
+        pop     ax
         ret
 
@@ -97 +104 @@
         push    ecx
         pushfd
+%ifdef BS3_STRICT
+        mov     ax, ds
+        cmp     ax, BS3_ADDR_BS3DATA16 >> 4
+        je      .real_mode_ds_ok
+        hlt
+.real_mode_ds_ok:
+%endif
 
         ;