/*
* (C) Copyright 2002
* Daniel Engström, Omicron Ceti AB, daniel@omicron.se
- *
+ *
* See file CREDITS for list of people who contributed to this
* project.
*
#define REALMODE_MAILBOX ((char*)0xe00)
+extern ulong _i386boot_realmode;
+extern ulong _i386boot_realmode_size;
extern char realmode_enter;
int realmode_setup(void)
{
+ ulong i386boot_realmode = (ulong)&_i386boot_realmode;
+ ulong i386boot_realmode_size = (ulong)&_i386boot_realmode_size;
+
/* copy the realmode switch code */
if (i386boot_realmode_size > (REALMODE_MAILBOX-REALMODE_BASE)) {
- printf("realmode switch too large (%ld bytes, max is %d)\n",
+ printf("realmode switch too large (%ld bytes, max is %d)\n",
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)) {
printf("Warning: entering realmode with sp < 4 will fail\n");
}
-
+
memcpy(REALMODE_MAILBOX, in, sizeof(struct pt_regs));
asm("wbinvd\n");
-
- __asm__ volatile (
+
+ __asm__ volatile (
"lcall $0x20,%0\n" : : "i" (&realmode_enter) );
asm("wbinvd\n");
writeb(lvl, 0x701);
writeb(0xcb, 0x702); /* lret */
asm("wbinvd\n");
-
- enter_realmode(0x00, 0x700, in, out);
-
+
+ enter_realmode(0x00, 0x700, in, out);
+
return out->eflags&1;
}
-