Calling BIOS interrupt from kernel (and debugging / reverse engeneering)

Rafał Maj
2007-08-22T07:56:21Z

Hello,
I know it is not good to call BIOS interrupt from Linux (kernel nor
userspace) and we should use I/O ports instead;

But, is it at all doable? To call a BIOS interrupt from Linux kernel?

If so then how to?

In example, say we have not documented device returning data in AL
after call to interrupt 0x15 with AX=0x1234 for example; And we want to
use this BIOS interrupt and then printk() returned value in AL.

AFAIK vm86() is one step to do it, but its hard to find good complete
example at least for me.

Btw, is it possible to reverse engineering such a BIOS call? Besides
using some hardware-debugger of bus etc.

Thanks