Patch "irqchip/gic-v3-its: Fix double ICC_EOIR write for LPI in EOImode==1" has been added to the 4.4-stable tree

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

    irqchip/gic-v3-its: Fix double ICC_EOIR write for LPI in EOImode==1

to the 4.4-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:
irqchip-gic-v3-its-fix-double-icc_eoir-write-for-lpi-in-eoimode-1.patch
and it can be found in the queue-4.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Ashok Kumar <[email protected]>
Date: Thu, 11 Feb 2016 05:38:53 -0800
Subject: irqchip/gic-v3-its: Fix double ICC_EOIR write for LPI in EOImode==1

From: Ashok Kumar <[email protected]>

commit 004fa08d7aba2a13974446bf212a48c0b3b0d9fd upstream.

When the GIC is using EOImode==1, the EOI is done immediately, leaving the deactivation to be performed when the EOI was previously done.

Unfortunately, the ITS is not aware of the EOImode at all, and blindly EOIs the interrupt again. On most systems, this is ignored (despite being a programming error), but some others do raise a SError exception as there is no priority drop to perform for this interrupt.

The fix is to stop trying to be clever, and always call into the underlying GIC to perform the right access, irrespective of the more we're in.

[Marc: Reworked commit message]

---
 drivers/irqchip/irq-gic-v3-its.c |    7 +------
 1 file changed, 1 insertion(+), 6 deletions(-)

@@ -597,11 +597,6 @@ static void its_unmask_irq(struct irq_da
 	lpi_set_config(d, true);
 }
 
-static void its_eoi_irq(struct irq_data *d)
-{
-	gic_write_eoir(d->hwirq);
-}
-
 static int its_set_affinity(struct irq_data *d, const struct cpumask *mask_val,
 			    bool force)
 {

@@ -638,7 +633,7 @@ static struct irq_chip its_irq_chip = {
 	.name			= "ITS",
 	.irq_mask		= its_mask_irq,
 	.irq_unmask		= its_unmask_irq,
-	.irq_eoi		= its_eoi_irq,
+	.irq_eoi		= irq_chip_eoi_parent,
 	.irq_set_affinity	= its_set_affinity,
 	.irq_compose_msi_msg	= its_irq_compose_msi_msg,
 };

Patches currently in stable-queue which might be from [email protected] are

queue-4.4/irqchip-gic-v3-its-fix-double-icc_eoir-write-for-lpi-in-eoimode-1.patch