Petr Vandrovec writes:
> On 12 Sep 00 at 21:25, Keith Owens wrote:
> > >0x85) vanish after the system has booted further. printk shows that
> > >idt_table is correctly updated immediately after the set_system_gate
> > >but once the system has booted the entries for my new traps have
> > >reverted. (printk telemetry available on request). However, once the
> > >system has booted, a little module which simply updates
> > >idt_table[MY_NEW_VECTOR] directly works fine and "sticks". Help?
> > >(Or, more accurately "Aaarrrgh?").
> >
> > I can confirm that this sometimes occurs in 2.4.0-testx, AFAIK I have
> > only seen the problem in SMP kernels.
>
> What about arch/i386/kernel/io_apic.c:assign_irq_vector() ?
I'm not using SMP but you both put me on the right track.
init/main.c:start_kernel does:
setup_arch(&command_line);
trap_init();
init_IRQ();
trap_init does the set_system_gate(FOO_VECTOR, &handler) lines I
extended but then init_IRQ() does
for (i = 0; i < NR_IRQS; i++) {
int vector = FIRST_EXTERNAL_VECTOR + i;
if (vector != SYSCALL_VECTOR)
set_intr_gate(vector, interrupt[i]);
}
and promptly zaps everything except SYSCALL_VECTOR.
(FIRST_EXTERNAL_VECTOR is 0x20). Many thanks.
--Malcolm
-- Malcolm Beattie <mbeattie@sable.ox.ac.uk> Unix Systems Programmer Oxford University Computing Services - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org Please read the FAQ at http://www.tux.org/lkml/
This archive was generated by hypermail 2b29 : Fri Sep 15 2000 - 21:00:17 EST