diff options
Diffstat (limited to 'lib_i386/realmode.c')
| -rw-r--r-- | lib_i386/realmode.c | 44 |
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; +} + |