genirq: Provide IRQCHIP_AFFINITY_PRE_STARTUP

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commit 826da77129 upstream.

X86 IO/APIC and MSI interrupts (when used without interrupts remapping)
require that the affinity setup on startup is done before the interrupt is
enabled for the first time as the non-remapped operation mode cannot safely
migrate enabled interrupts from arbitrary contexts. Provide a new irq chip
flag which allows affected hardware to request this.

This has to be opt-in because there have been reports in the past that some
interrupt chips cannot handle affinity setting before startup.

Fixes: 1840475676 ("genirq: Expose default irq affinity mask (take 3)")
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Marc Zyngier <maz@kernel.org>
Reviewed-by: Marc Zyngier <maz@kernel.org>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20210729222542.779791738@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

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Thomas Gleixner 2021-07-29 23:51:48 +02:00 • committed by Greg Kroah-Hartman

parent 2a28b52306

commit 4e52a4fe6f

2 changed files with 6 additions and 1 deletions

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2

include/linux/irq.h

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5

kernel/irq/chip.c

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