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Commit bbc3dfe8 authored by Sam Mendoza-Jonas's avatar Sam Mendoza-Jonas Committed by Michael Ellerman
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tty/hvc: Use IRQF_SHARED for OPAL hvc consoles 



Commit 2def86a7 ("hvc: Convert to using interrupts instead of opal
events") enabled the use of interrupts in the hvc_driver for OPAL
platforms. However on machines with more than one hvc console, any
console after the first will fail to register an interrupt handler in
notifier_add_irq() since all consoles share the same IRQ number but do
not set the IRQF_SHARED flag:

  genirq: Flags mismatch irq 31. 00000000 (hvc_console) vs. 00000000 (hvc_console)
  hvc_open: request_irq failed with rc -16.

This error propagates up to hvc_open() and the console is closed, but
OPAL will still generate interrupts that are not handled, leading to
rcu_sched stall warnings.

Set IRQF_SHARED when calling request_irq(), allowing additional consoles
to start properly. This is only set for consoles handled by
hvc_opal_probe(), leaving other types unaffected.

Signed-off-by: default avatarSamuel Mendoza-Jonas <sam@mendozajonas.com>
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
parent a431b946

drivers/tty/hvc/hvc_console.h

+1 −0
Original line number Diff line number Diff line
@@ -60,6 +60,7 @@ struct hvc_struct { 
	struct winsize ws;

	struct work_struct tty_resize;

	struct list_head next;

	unsigned long flags;

};



/* implemented by a low level driver */

drivers/tty/hvc/hvc_irq.c

+7 −2
Original line number Diff line number Diff line
@@ -14,6 +14,11 @@ static irqreturn_t hvc_handle_interrupt(int irq, void *dev_instance) 
	/* if hvc_poll request a repoll, then kick the hvcd thread */

	if (hvc_poll(dev_instance))

		hvc_kick();



	/*

	 * We're safe to always return IRQ_HANDLED as the hvcd thread will

	 * iterate through each hvc_struct.

	 */

	return IRQ_HANDLED;

}
@@ -28,7 +33,7 @@ int notifier_add_irq(struct hvc_struct *hp, int irq) 
		hp->irq_requested = 0;

		return 0;

	}

	rc = request_irq(irq, hvc_handle_interrupt, 0,

	rc = request_irq(irq, hvc_handle_interrupt, hp->flags,

			"hvc_console", hp);

	if (!rc)

		hp->irq_requested = 1;

drivers/tty/hvc/hvc_opal.c

+3 −0
Original line number Diff line number Diff line
@@ -224,6 +224,9 @@ static int hvc_opal_probe(struct platform_device *dev) 
	hp = hvc_alloc(termno, irq, ops, MAX_VIO_PUT_CHARS);

	if (IS_ERR(hp))

		return PTR_ERR(hp);



	/* hvc consoles on powernv may need to share a single irq */

	hp->flags = IRQF_SHARED;

	dev_set_drvdata(&dev->dev, hp);



	return 0;