Re: [RFC PATCH v2 0/7] Pseudo-NMI for arm64 using ICC_PMR_EL1 (GICv3)

From: Daniel Thompson
Date: Fri Sep 18 2015 - 06:26:46 EST


On 18/09/15 06:11, Jon Masters wrote:
On Sep 14, 2015, at 06:26, Daniel Thompson <daniel.thompson@xxxxxxxxxx> wrote:
This patchset provides a pseudo-NMI for arm64 kernels by reimplementing
the irqflags macros to modify the GIC PMR (the priority mask register is
accessible as a system register on GICv3 and later) rather than the
PSR. The patchset includes an implementation of
arch_trigger_all_cpu_backtrace() for arm64 allowing the new code to be
exercised.

I think there is a need to connect a few dots on this next week
during Connect. Some other conversations have discussed alternative
implementations elsewhere. I will assist.

Fine by me.

I'd be very happy to talk about alternative approaches. In the past I've had long conversations about trapping to ARM TF as a means to simulate NMI. I haven't written any code to move in this direction but I still think of it as being the future-areas-of-interest pile.

That said, whenever I search for (what I think are) sensible keywords for this subject I generally only find my own work! I may be selecting a rather blinkered set of keywords when I search but nevertheless it does mean I will probably have to rely on you to make introductions!


Daniel.
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