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Date: Sun, 17 Oct 2010 00:59:11 +0100 (BST) From: "Maciej W. Rozycki" <macro@...ux-mips.org> To: Cyrill Gorcunov <gorcunov@...il.com> cc: Don Zickus <dzickus@...hat.com>, Andi Kleen <andi@...stfloor.org>, mingo@...e.hu, fweisbec@...il.com, robert.richter@....com, linux-kernel@...r.kernel.org Subject: Re: [RFC] arch generic way to trigger unknown NMIs On Sat, 16 Oct 2010, Cyrill Gorcunov wrote: > > > Hi Maciej, the send_IPI_self could be modified to send NMI (at moment it > > > uses self shortcut with fixed delivery mode). The question is rather if > > > we need it without a real caller yet. When Don's patch gets merged we > > > will have a real caller then and could update send_IPI_self to support > > > NMI delivery mode. Something like that :) > > > > Sounds backwards to me. My understanding is a need has just arisen, so > > why not: > > > > 1. Update send_IPI_self(). > > > > 2. Add code that makes use of the new functionality. > > > > 3. Submit all the changes as self-contained patches in a single series to > > be applied at the same time. > > > > ? That's what I'd imagine the most natural way of doing this would be. > > Well, Maciej I believe the problem is not in modifying send_IPI_self > but rather _how_ to make it more natural and do not introduce overhead. > apic code is already weird enough :) Need to think. > > ( > btw, we will have to add additional flag which would check for NMI > being generated by "NMI-tester" and make a second apic write to > ICR to deassert level line, ie it could be something like > > apic->send_IPI_self(NMI_VECTOR) ; with asserts level > default_do_nmi() ; check for NMI being sent for testing purpose > apic->send_IPI_self(NMI_VECTOR) ; with deasserts level > > iirc apic itself doesn't deassert nmi line on message with > nmi deliver mode arrival > ) How different is it to the other two send_IPI shorthand calls? Or the fully-fledged one? I gather from this thread they already handle NMIs properly, so what is there within that cannot simply be copied over to this one? Maciej -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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