Re: RFC: do get_rtc_time() correctly

From: Alan Cox
Date: Thu Aug 16 2007 - 05:58:20 EST


> I understand that SMM/SMI servicing can take a long time, but SMM/SMI
> shouldn't happen while interrupts are masked using local_irq_disable()

Don't bet on it.

> [included in spin_lock_irq()], at least on x86-architectures. If
> SMM/SMI can happen even then, the NMI fix below could be generalized.
>
> My mention of NMI (which by definition can't be masked) is because NMI

On x86 you can mask NMI briefly if you are willing to do a bit of CPU
abuse. Force an NMI, longjmp out of the handler, and NMI is off until the
next iret instruction or similar.

We don't do this and I think Linus would object to anyone who did 8)
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/