The patch below does not apply to the 4.9-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 826da771291fc25a428e871f9e7fb465e390f852 Mon Sep 17 00:00:00 2001
From: Thomas Gleixner tglx@linutronix.de Date: Thu, 29 Jul 2021 23:51:48 +0200 Subject: [PATCH] genirq: Provide IRQCHIP_AFFINITY_PRE_STARTUP
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: 18404756765c ("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
diff --git a/include/linux/irq.h b/include/linux/irq.h index 8e9a9ae471a6..c8293c817646 100644 --- a/include/linux/irq.h +++ b/include/linux/irq.h @@ -569,6 +569,7 @@ struct irq_chip { * IRQCHIP_SUPPORTS_NMI: Chip can deliver NMIs, only for root irqchips * IRQCHIP_ENABLE_WAKEUP_ON_SUSPEND: Invokes __enable_irq()/__disable_irq() for wake irqs * in the suspend path if they are in disabled state + * IRQCHIP_AFFINITY_PRE_STARTUP: Default affinity update before startup */ enum { IRQCHIP_SET_TYPE_MASKED = (1 << 0), @@ -581,6 +582,7 @@ enum { IRQCHIP_SUPPORTS_LEVEL_MSI = (1 << 7), IRQCHIP_SUPPORTS_NMI = (1 << 8), IRQCHIP_ENABLE_WAKEUP_ON_SUSPEND = (1 << 9), + IRQCHIP_AFFINITY_PRE_STARTUP = (1 << 10), };
#include <linux/irqdesc.h> diff --git a/kernel/irq/chip.c b/kernel/irq/chip.c index 7f04c7d8296e..a98bcfc4be7b 100644 --- a/kernel/irq/chip.c +++ b/kernel/irq/chip.c @@ -265,8 +265,11 @@ int irq_startup(struct irq_desc *desc, bool resend, bool force) } else { switch (__irq_startup_managed(desc, aff, force)) { case IRQ_STARTUP_NORMAL: + if (d->chip->flags & IRQCHIP_AFFINITY_PRE_STARTUP) + irq_setup_affinity(desc); ret = __irq_startup(desc); - irq_setup_affinity(desc); + if (!(d->chip->flags & IRQCHIP_AFFINITY_PRE_STARTUP)) + irq_setup_affinity(desc); break; case IRQ_STARTUP_MANAGED: irq_do_set_affinity(d, aff, false);