[PATCH V2 1/2] tty/hvc: Use IRQF_SHARED for OPAL hvc consoles
From: Samuel Mendoza-Jonas <sam@mendozajonas.com>
Date: 2016-07-11 03:40:16
Also in:
stable
Subsystem:
hypervisor virtual console driver, linux for powerpc (32-bit and 64-bit), the rest, tty layer and serial drivers · Maintainers:
Madhavan Srinivasan, Linus Torvalds, Greg Kroah-Hartman, Jiri Slaby
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@mendozajonas.com>
Cc: <redacted> # 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