Patch "powerpc/opal-irqchip: Fix double endian conversion" has been added to the 4.3-stable tree

Patch "powerpc/opal-irqchip: Fix double endian conversion" has been added to the 4.3-stable tree

[gregkh]

This is a note to let you know that I've just added the patch titled

    powerpc/opal-irqchip: Fix double endian conversion

to the 4.3-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     powerpc-opal-irqchip-fix-double-endian-conversion.patch
and it can be found in the queue-4.3 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From 25642e1459ace29f6ce5a171efc8b7b59a52a2d4 Mon Sep 17 00:00:00 2001
From: Alistair Popple <alistair@popple.id.au>
Date: Mon, 7 Dec 2015 11:28:28 +1100
Subject: powerpc/opal-irqchip: Fix double endian conversion

From: Alistair Popple <alistair@popple.id.au>

commit 25642e1459ace29f6ce5a171efc8b7b59a52a2d4 upstream.

The OPAL event calls return a mask of events that are active in big
endian format. This is checked when unmasking the events in the
irqchip by comparison with a cached value. The cached value was stored
in big endian format but should've been converted to CPU endian
first.

This bug leads to OPAL event delivery being delayed or dropped on some
systems. Symptoms may include a non-functional console.

The bug is fixed by calling opal_handle_events(...) instead of
duplicating code in opal_event_unmask(...).

Fixes: 9f0fd0499d30 ("powerpc/powernv: Add a virtual irqchip for opal events")
Reported-by: Douglas L Lehr <dllehr@us.ibm.com>
Signed-off-by: Alistair Popple <alistair@popple.id.au>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 arch/powerpc/platforms/powernv/opal-irqchip.c |   58 +++++++++++++-------------
 1 file changed, 29 insertions(+), 29 deletions(-)

--- a/arch/powerpc/platforms/powernv/opal-irqchip.c
+++ b/arch/powerpc/platforms/powernv/opal-irqchip.c
@@ -43,11 +43,34 @@ static unsigned int opal_irq_count;
 static unsigned int *opal_irqs;
 
 static void opal_handle_irq_work(struct irq_work *work);
-static __be64 last_outstanding_events;
+static u64 last_outstanding_events;
 static struct irq_work opal_event_irq_work = {
 	.func = opal_handle_irq_work,
 };
 
+void opal_handle_events(uint64_t events)
+{
+	int virq, hwirq = 0;
+	u64 mask = opal_event_irqchip.mask;
+
+	if (!in_irq() && (events & mask)) {
+		last_outstanding_events = events;
+		irq_work_queue(&opal_event_irq_work);
+		return;
+	}
+
+	while (events & mask) {
+		hwirq = fls64(events) - 1;
+		if (BIT_ULL(hwirq) & mask) {
+			virq = irq_find_mapping(opal_event_irqchip.domain,
+						hwirq);
+			if (virq)
+				generic_handle_irq(virq);
+		}
+		events &= ~BIT_ULL(hwirq);
+	}
+}
+
 static void opal_event_mask(struct irq_data *d)
 {
 	clear_bit(d->hwirq, &opal_event_irqchip.mask);
@@ -55,12 +78,12 @@ static void opal_event_mask(struct irq_d
 
 static void opal_event_unmask(struct irq_data *d)
 {
+	__be64 events;
+
 	set_bit(d->hwirq, &opal_event_irqchip.mask);
 
-	opal_poll_events(&last_outstanding_events);
-	if (last_outstanding_events & opal_event_irqchip.mask)
-		/* Need to retrigger the interrupt */
-		irq_work_queue(&opal_event_irq_work);
+	opal_poll_events(&events);
+	opal_handle_events(be64_to_cpu(events));
 }
 
 static int opal_event_set_type(struct irq_data *d, unsigned int flow_type)
@@ -96,29 +119,6 @@ static int opal_event_map(struct irq_dom
 	return 0;
 }
 
-void opal_handle_events(uint64_t events)
-{
-	int virq, hwirq = 0;
-	u64 mask = opal_event_irqchip.mask;
-
-	if (!in_irq() && (events & mask)) {
-		last_outstanding_events = events;
-		irq_work_queue(&opal_event_irq_work);
-		return;
-	}
-
-	while (events & mask) {
-		hwirq = fls64(events) - 1;
-		if (BIT_ULL(hwirq) & mask) {
-			virq = irq_find_mapping(opal_event_irqchip.domain,
-						hwirq);
-			if (virq)
-				generic_handle_irq(virq);
-		}
-		events &= ~BIT_ULL(hwirq);
-	}
-}
-
 static irqreturn_t opal_interrupt(int irq, void *data)
 {
 	__be64 events;
@@ -131,7 +131,7 @@ static irqreturn_t opal_interrupt(int ir
 
 static void opal_handle_irq_work(struct irq_work *work)
 {
-	opal_handle_events(be64_to_cpu(last_outstanding_events));
+	opal_handle_events(last_outstanding_events);
 }
 
 static int opal_event_match(struct irq_domain *h, struct device_node *node,


Patches currently in stable-queue which might be from alistair@popple.id.au are

queue-4.3/powerpc-opal-irqchip-fix-double-endian-conversion.patch
queue-4.3/powerpc-opal-irqchip-fix-deadlock-introduced-by-fix-double-endian-conversion.patch