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tty/hvc: Use IRQF_SHARED for OPAL hvc consoles 

Commit 2def86a720 ("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: Samuel Mendoza-Jonas <sam@mendozajonas.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
This commit is contained in:
Sam Mendoza-Jonas 2016-07-11 13:38:57 +10:00 committed by Michael Ellerman
parent a431b946db
commit bbc3dfe880
3 changed files with 11 additions and 2 deletions
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1
drivers/tty/hvc/hvc_console.h
View File

@ -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 */

9
drivers/tty/hvc/hvc_irq.c
View File

@ -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;
}
@ -28,8 +33,8 @@ int notifier_add_irq(struct hvc_struct *hp, int irq)
hp->irq_requested = 0;
return 0;
}
rc = request_irq(irq, hvc_handle_interrupt, 0,
"hvc_console", hp);
rc = request_irq(irq, hvc_handle_interrupt, hp->flags,
"hvc_console", hp);
if (!rc)
hp->irq_requested = 1;
return rc;

3
drivers/tty/hvc/hvc_opal.c
View File

@ -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;