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Diffstat (limited to 'lib_i386/realmode.c')
-rw-r--r--lib_i386/realmode.c44
1 files changed, 35 insertions, 9 deletions
diff --git a/lib_i386/realmode.c b/lib_i386/realmode.c
index 27d4693..d7bb81c 100644
--- a/lib_i386/realmode.c
+++ b/lib_i386/realmode.c
@@ -33,25 +33,33 @@
extern char realmode_enter;
-
-int enter_realmode(u16 seg, u16 off, struct pt_regs *in, struct pt_regs *out)
+int realmode_setup(void)
{
-
- /* setup out thin bios emulation */
- if (bios_setup()) {
- return -1;
- }
-
/* copy the realmode switch code */
if (i386boot_realmode_size > (REALMODE_MAILBOX-REALMODE_BASE)) {
printf("realmode switch too large (%ld bytes, max is %d)\n",
- i386boot_realmode_size, (int)(REALMODE_MAILBOX-REALMODE_BASE));
+ i386boot_realmode_size, (REALMODE_MAILBOX-REALMODE_BASE));
return -1;
}
memcpy(REALMODE_BASE, (void*)i386boot_realmode, i386boot_realmode_size);
+ asm("wbinvd\n");
+
+ return 0;
+}
+int enter_realmode(u16 seg, u16 off, struct pt_regs *in, struct pt_regs *out)
+{
+ /* setup out thin bios emulation */
+ if (bios_setup()) {
+ return -1;
+ }
+
+ if (realmode_setup()) {
+ return -1;
+ }
+
in->eip = off;
in->xcs = seg;
if (3>(in->esp & 0xffff)) {
@@ -59,12 +67,30 @@ int enter_realmode(u16 seg, u16 off, struct pt_regs *in, struct pt_regs *out)
}
memcpy(REALMODE_MAILBOX, in, sizeof(struct pt_regs));
+ asm("wbinvd\n");
__asm__ volatile (
"lcall $0x20,%0\n" : : "i" (&realmode_enter) );
+ asm("wbinvd\n");
memcpy(out, REALMODE_MAILBOX, sizeof(struct pt_regs));
return out->eax;
}
+
+/* This code is supposed to access a realmode interrupt
+ * it does currently not work for me */
+int enter_realmode_int(u8 lvl, struct pt_regs *in, struct pt_regs *out)
+{
+ /* place two instructions at 0x700 */
+ writeb(0xcd, 0x700); /* int $lvl */
+ writeb(lvl, 0x701);
+ writeb(0xcb, 0x702); /* lret */
+ asm("wbinvd\n");
+
+ enter_realmode(0x00, 0x700, in, out);
+
+ return out->eflags&1;
+}
+