>
>
> On Sat, 11 Jul 1998, Richard B. Johnson wrote:
> >
> > No. That just masks the problem. It is common for Linux interrupt handlers
> > to enable interrupts. They must _not_ be reentered. The kernel IRQ code
> > should:
>
> Note that the kernel IRQ code _does_ this. It's harder to do with the
> IO-APIC, but it's actually done fairly cleanly and straightforwardly, and
> there is a very simple atomic flag that makes sure of that even if the
> hardware tries to get recursive interrupts through (which can actually
> happen reasonably easily on systems that send interrupts to multiple
> CPU's, and where the kernel needs to make sure that only one of them is
> accepted).
You are correct. There may be a "buzz" in hardware that lets an
occasional spurious interrupt through, but the code does and should
prevent re-entry.
[SNIPPED other info]
Thanks for confirming.
Cheers,
Dick Johnson
***** FILE SYSTEM MODIFIED *****
Penguin : Linux version 2.1.108 on an i586 machine (66.15 BogoMips).
Warning : It's hard to remain at the trailing edge of technology.
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.rutgers.edu
Please read the FAQ at http://www.altern.org/andrebalsa/doc/lkml-faq.html