linux_dsm_epyc7002/drivers/tty/hvc/hvc_irq.c
Sam Mendoza-Jonas bbc3dfe880 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>
2016-07-27 12:38:18 +10:00

55 lines
1013 B
C

/*
* Copyright IBM Corp. 2001,2008
*
* This file contains the IRQ specific code for hvc_console
*
*/
#include <linux/interrupt.h>
#include "hvc_console.h"
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;
}
/*
* For IRQ based systems these callbacks can be used
*/
int notifier_add_irq(struct hvc_struct *hp, int irq)
{
int rc;
if (!irq) {
hp->irq_requested = 0;
return 0;
}
rc = request_irq(irq, hvc_handle_interrupt, hp->flags,
"hvc_console", hp);
if (!rc)
hp->irq_requested = 1;
return rc;
}
void notifier_del_irq(struct hvc_struct *hp, int irq)
{
if (!hp->irq_requested)
return;
free_irq(irq, hp);
hp->irq_requested = 0;
}
void notifier_hangup_irq(struct hvc_struct *hp, int irq)
{
notifier_del_irq(hp, irq);
}