Messages in this thread |  | | | Date | Tue, 14 Dec 2004 15:09:35 -0800 (PST) | | From | Linus Torvalds <> | | Subject | Re: [patch, 2.6.10-rc3] safe_hlt() & NMIs |
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On Tue, 14 Dec 2004, Ingo Molnar wrote: > > find the correct patch below. I've tested it with an NMI watchdog > frequency artificially increased to 10 KHz, and i've instrumented the > new branch in the NMI handler, but even under heavy IRQ load i was not > able to trigger the branch. Maybe newer CPUs handle this case somehow > and make sti;hlt truly atomic?
Now that you mention it, I have this dim memory of the one-instruction "sti-shadow" actually disabling NMI's (and debug traps) too. The CPU literally doesn't test for async events following "sti".
Or maybe that was "mov->ss". That one also has that strange "black hole" for one instruction. Hmm.. You could be evil and try to fill up 64kB worth of memory with a "mov %ax,%ss", and jump to it in vm86 mode and see what happens. The eip will just keep wrapping around...
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