[PATCH v5 1/5] arm64: Add framework to turn IPI as NMI
Marc Zyngier
maz at kernel.org
Mon Oct 19 07:56:25 EDT 2020
On 2020-10-14 12:12, Sumit Garg wrote:
> Introduce framework to turn an IPI as NMI using pseudo NMIs. In case a
> particular platform doesn't support pseudo NMIs, then request IPI as a
> regular IRQ.
>
> The main motivation for this feature is to have an IPI that can be
> leveraged to invoke NMI functions on other CPUs. And current
> prospective
> users are NMI backtrace and KGDB CPUs round-up whose support is added
> via future patches.
>
> Signed-off-by: Sumit Garg <sumit.garg at linaro.org>
> ---
> arch/arm64/include/asm/nmi.h | 16 +++++++++
> arch/arm64/kernel/Makefile | 2 +-
> arch/arm64/kernel/ipi_nmi.c | 77
> ++++++++++++++++++++++++++++++++++++++++++++
> 3 files changed, 94 insertions(+), 1 deletion(-)
> create mode 100644 arch/arm64/include/asm/nmi.h
> create mode 100644 arch/arm64/kernel/ipi_nmi.c
[...]
> + irq_set_status_flags(ipi, IRQ_HIDDEN);
Another thing is this. Why are you hiding this from /proc/interrupts?
The only reason the other IPIs are hidden is that displaying them as
"normal" interrupts would be a change in userspace ABI.
In your case, this is something new that can perfectly appear as
a standard interrupt (and I don't see how you'd display the
statistics otherwise).
M.
--
Jazz is not dead. It just smells funny...
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