[PATCH v3 0/4] Provide core API for NMIs

[Julien Thierry]

Hi,

This patch series provides a way for irqchips to define some IRQs as NMIs.

For this to be possible, the irqchip must:
- be a root irqchip
- not require bus locking
- have the NMI support flag

Once these conditions are met, interrupt lines can be requested as NMIs.
These lines must not be shared and the IRQ handling must not be threaded.
Callbacks are added to the irqchip in order to set up (clean up) the
necessary resources for NMIs before enabling (before releasing) the
corresponding interrupt line.

I'll soon post a series making use of the API for Arm's GICv3.

Patches 1 & 2 provide functions necessary to request and manage NMIs.
Patches 3 & 4 provide functions for NMI handling.

Changes since v2[1]:
- Fix ARM build error reported by kbuild bot
- Fix documentation warnings reported by kbuild bot

Changes since v1[2]:
- Rebased to v4.19-rc1
- Fix some coding style issues

Changes since RFC[3]:
- Rebased to v4.18-rc6
- Remove disable_nmi, one should call disable_nmi_nosync instead
- Remove code related to affinity balancing from NMI functions
- Require PERCPU configuration for NMIs

[1] https://lkml.org/lkml/2018/8/28/661
[2] https://lkml.org/lkml/2018/7/24/321
[3] https://lkml.org/lkml/2018/7/9/768

Cheers,

Julien

-->

Julien Thierry (4):
  genirq: Provide basic NMI management for interrupt lines
  genirq: Provide NMI management for percpu_devid interrupts
  genirq: Provide NMI handlers
  irqdesc: Add domain handler for NMIs

 include/linux/interrupt.h |  18 +++
 include/linux/irq.h       |  10 ++
 include/linux/irqdesc.h   |   5 +
 kernel/irq/chip.c         |  54 +++++++
 kernel/irq/debugfs.c      |   6 +-
 kernel/irq/internals.h    |   2 +
 kernel/irq/irqdesc.c      |  35 +++++
 kernel/irq/manage.c       | 377 +++++++++++++++++++++++++++++++++++++++++++++-
 8 files changed, 504 insertions(+), 3 deletions(-)

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1.9.1