alistair23-linux/kernel/irq
Thomas Gleixner baedb87d1b genirq/affinity: Handle affinity setting on inactive interrupts correctly
Setting interrupt affinity on inactive interrupts is inconsistent when
hierarchical irq domains are enabled. The core code should just store the
affinity and not call into the irq chip driver for inactive interrupts
because the chip drivers may not be in a state to handle such requests.

X86 has a hacky workaround for that but all other irq chips have not which
causes problems e.g. on GIC V3 ITS.

Instead of adding more ugly hacks all over the place, solve the problem in
the core code. If the affinity is set on an inactive interrupt then:

    - Store it in the irq descriptors affinity mask
    - Update the effective affinity to reflect that so user space has
      a consistent view
    - Don't call into the irq chip driver

This is the core equivalent of the X86 workaround and works correctly
because the affinity setting is established in the irq chip when the
interrupt is activated later on.

Note, that this is only effective when hierarchical irq domains are enabled
by the architecture. Doing it unconditionally would break legacy irq chip
implementations.

For hierarchial irq domains this works correctly as none of the drivers can
have a dependency on affinity setting in inactive state by design.

Remove the X86 workaround as it is not longer required.

Fixes: 02edee152d ("x86/apic/vector: Ignore set_affinity call for inactive interrupts")
Reported-by: Ali Saidi <alisaidi@amazon.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Ali Saidi <alisaidi@amazon.com>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20200529015501.15771-1-alisaidi@amazon.com
Link: https://lkml.kernel.org/r/877dv2rv25.fsf@nanos.tec.linutronix.de
2020-07-17 23:30:43 +02:00
..
affinity.c genirq/affinity: Remove const qualifier from node_to_cpumask argument 2019-08-28 12:20:43 +02:00
autoprobe.c
chip.c genirq: Provide interrupt injection mechanism 2020-03-08 11:06:42 +01:00
cpuhotplug.c genirq, sched/isolation: Isolate from handling managed interrupts 2020-01-22 16:29:49 +01:00
debug.h
debugfs.c genirq: Provide interrupt injection mechanism 2020-03-08 11:06:42 +01:00
devres.c
dummychip.c
generic-chip.c
handle.c x86 entry code updates: 2020-03-30 19:14:28 -07:00
internals.h genirq: Provide interrupt injection mechanism 2020-03-08 11:06:42 +01:00
ipi.c
irq_sim.c genirq/irq_sim: Simplify the API 2020-05-18 10:30:21 +01:00
irqdesc.c genirq: Add protection against unsafe usage of generic_handle_irq() 2020-03-08 11:06:40 +01:00
irqdomain.c irqdomain: Allow software nodes for IRQ domain creation 2020-05-21 10:53:17 +01:00
Kconfig treewide: replace '---help---' in Kconfig files with 'help' 2020-06-14 01:57:21 +09:00
Makefile
manage.c genirq/affinity: Handle affinity setting on inactive interrupts correctly 2020-07-17 23:30:43 +02:00
matrix.c
migration.c
msi.c x86/apic/msi: Plug non-maskable MSI affinity race 2020-02-01 09:31:47 +01:00
pm.c PCI: irq: Introduce rearm_wake_irq() 2019-07-23 09:37:51 +02:00
proc.c genirq/proc: Reject invalid affinity masks (again) 2020-02-14 09:43:17 +01:00
resend.c genirq: Provide interrupt injection mechanism 2020-03-08 11:06:42 +01:00
settings.h
spurious.c genirq: Add missing __must_hold() sparse annotation 2020-01-09 18:03:37 +01:00
timings.c