NMI via task gate

[Adam Lackorzynski]

On Sat Aug 04, 2007 at 11:50:36 +0200, Stefan Scheler wrote:
> > I'd suggest to use a task gate for your NMI and run it on a completely
> > different stack. Because there are parts of code that are extremely
> > sensible to NMIs and this is basically the sysenter path of the Fiasco
> > kernel.
> 
> I tried that (see attached patch). Is that the correct way of
> implementing this? It works exactly once. When I reset the counters the
> second time I get "APIC error 00000000(00000000)" and the machine freezes.
> 
> -- 
> Stefan Scheler

> +++ src/kern/config_gdt.h	(working copy)
> @@ -22,6 +22,7 @@
>  #define GDT_DATA_USER		(0x20)		// #4
>  #define GDT_TSS			(0x28)		// #5: hardware task segment
>  #define GDT_TSS_DBF		(0x30)		// #6: tss for dbf handler
> +#define GDT_TSS_PMI		(0x32)		// #7: tss for pmi handler

JFYI, the 0x32 seems wrong, as you're overwriting the dbf slot. You need
to use some free slot, e.g. 0x60. 



Adam
-- 
Adam                 adam at os.inf.tu-dresden.de
  Lackorzynski         http://os.inf.tu-dresden.de/~adam/