From: Thomas Gleixner <tglx@linutronix.de>
To: Julien Thierry <julien.thierry@arm.com>
Cc: linux-kernel@vger.kernel.org,
ricardo.neri-calderon@linux.intel.com, marc.zyngier@arm.com,
peterz@infradead.org, mingo@kernel.org
Subject: Re: [RFC PATCH 1/4] genirq: Provide basic NMI management for interrupt lines
Date: Tue, 17 Jul 2018 11:22:25 +0200 (CEST) [thread overview]
Message-ID: <alpine.DEB.2.21.1807171114280.3238@nanos.tec.linutronix.de> (raw)
In-Reply-To: <1531152846-19374-2-git-send-email-julien.thierry@arm.com>
On Mon, 9 Jul 2018, Julien Thierry wrote:
> +/**
> + * disable_nmi_nosync - disable an nmi without waiting
> + * @irq: Interrupt to disable
> + *
> + * Disable the selected interrupt line. Disables and enables are
> + * nested.
> + * The interrupt to disable must have been requested through request_nmi.
> + * Unlike disable_nmi(), this function does not ensure existing
> + * instances of the IRQ handler have completed before returning.
> + */
> +void disable_nmi_nosync(unsigned int irq)
> +{
> + disable_irq_nosync(irq);
> +}
> +
> +/**
> + * disable_nmi - disable an nmi and wait for completion
> + * @irq: Interrupt to disable
> + *
> + * Disable the selected interrupt line. Enables and disables are
> + * nested.
> + * The interrupt to disable must have been requested through request_nmi.
> + * This function waits for any pending IRQ handlers for this interrupt
> + * to complete before returning. If you use this function while
> + * holding a resource the IRQ handler may need you will deadlock.
I don't see how that wait would work with NMIs.
> +/* This function must be called with desc->lock held */
> +static const void *__cleanup_nmi(unsigned int irq, struct irq_desc *desc)
> +{
> + const char *devname = NULL;
> +
> + desc->istate &= ~IRQS_NMI;
> +
> +#ifdef CONFIG_SMP
> + if (WARN_ON(desc->affinity_notify))
> + desc->affinity_notify = NULL;
> +#endif
We should not support that affinity notify horror for NMIs at all.
> + if (!WARN_ON(desc->action == NULL)) {
> + irq_pm_remove_action(desc, desc->action);
> + devname = desc->action->name;
> + unregister_handler_proc(irq, desc->action);
> +
> + kfree(desc->action);
> + desc->action = NULL;
> + }
> +
> + irq_settings_clr_disable_unlazy(desc);
> + irq_shutdown(desc);
> +
> +#ifdef CONFIG_SMP
> + /* make sure affinity_hint is cleaned up */
> + if (WARN_ON_ONCE(desc->affinity_hint))
> + desc->affinity_hint = NULL;
> +#endif
Especially not twice :)
Thanks,
tglx
next prev parent reply other threads:[~2018-07-17 9:22 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-07-09 16:14 [RFC PATCH 0/4] Provide core API for NMIs Julien Thierry
2018-07-09 16:14 ` [RFC PATCH 1/4] genirq: Provide basic NMI management for interrupt lines Julien Thierry
2018-07-17 9:22 ` Thomas Gleixner [this message]
2018-07-17 11:13 ` Julien Thierry
2018-07-17 11:28 ` Peter Zijlstra
2018-07-17 12:25 ` Julien Thierry
2018-07-17 15:48 ` Julien Thierry
2018-07-17 15:51 ` Peter Zijlstra
2018-07-17 16:35 ` Julien Thierry
2018-07-17 19:46 ` Thomas Gleixner
2018-07-18 8:09 ` Julien Thierry
2018-07-17 19:42 ` Thomas Gleixner
2018-07-09 16:14 ` [RFC PATCH 2/4] genirq: Provide NMI management for percpu_devid interrupts Julien Thierry
2018-07-09 16:14 ` [RFC PATCH 3/4] genirq: Provide NMI handlers Julien Thierry
2018-07-09 16:14 ` [RFC PATCH 4/4] irqdesc: Add domain handler for NMIs Julien Thierry
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