Commit 2def86a7200c
("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:
[ 51.179907] genirq: Flags mismatch irq 31. 00000000 (hvc_console) vs.
00000000 (hvc_console)
[ 51.180010] 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@xxxxxxxxxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx> # 4.1.x-
---
drivers/tty/hvc/hvc_console.h | 1 +
drivers/tty/hvc/hvc_irq.c | 7 +++++--
drivers/tty/hvc/hvc_opal.c | 3 +++
3 files changed, 9 insertions(+), 2 deletions(-)
diff --git a/drivers/tty/hvc/hvc_console.h b/drivers/tty/hvc/hvc_console.h
index 9131019..798c48d 100644
--- a/drivers/tty/hvc/hvc_console.h
+++ b/drivers/tty/hvc/hvc_console.h
@@ -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 */
diff --git a/drivers/tty/hvc/hvc_irq.c b/drivers/tty/hvc/hvc_irq.c
index c9adb05..57d9df7 100644
--- a/drivers/tty/hvc/hvc_irq.c
+++ b/drivers/tty/hvc/hvc_irq.c
@@ -14,6 +14,9 @@ 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 +31,8 @@ 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;
diff --git a/drivers/tty/hvc/hvc_opal.c b/drivers/tty/hvc/hvc_opal.c
index 47b54c6..b7cd0ae 100644
--- a/drivers/tty/hvc/hvc_opal.c
+++ b/drivers/tty/hvc/hvc_opal.c
@@ -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;
--
2.9.0
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