[ 3.5.y.z extended stable ] Patch "powerpc: Fix missing/delayed calls to irq_work" has been added to staging queue

[Luis Henriques]

This is a note to let you know that I have just added a patch titled

    powerpc: Fix missing/delayed calls to irq_work

to the linux-3.5.y-queue branch of the 3.5.y.z extended stable tree 
which can be found at:

 http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.5.y-queue

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.5.y.z tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Luis

------

>From 3de97afe43ff2ef1d94b80e14cb2c97004c28b7a Mon Sep 17 00:00:00 2001
From: Benjamin Herrenschmidt <benh at kernel.crashing.org>
Date: Sat, 15 Jun 2013 12:13:40 +1000
Subject: [PATCH] powerpc: Fix missing/delayed calls to irq_work

commit 230b3034793247f61e6a0b08c44cf415f6d92981 upstream.

When replaying interrupts (as a result of the interrupt occurring
while soft-disabled), in the case of the decrementer, we are exclusively
testing for a pending timer target. However we also use decrementer
interrupts to trigger the new "irq_work", which in this case would
be missed.

This change the logic to force a replay in both cases of a timer
boundary reached and a decrementer interrupt having actually occurred
while disabled. The former test is still useful to catch cases where
a CPU having been hard-disabled for a long time completely misses the
interrupt due to a decrementer rollover.

Signed-off-by: Benjamin Herrenschmidt <benh at kernel.crashing.org>
Tested-by: Steven Rostedt <rostedt at goodmis.org>
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
 arch/powerpc/kernel/irq.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/powerpc/kernel/irq.c b/arch/powerpc/kernel/irq.c
index 1f017bb..86cb68e 100644
--- a/arch/powerpc/kernel/irq.c
+++ b/arch/powerpc/kernel/irq.c
@@ -162,7 +162,7 @@ notrace unsigned int __check_irq_replay(void)
 	 * in case we also had a rollover while hard disabled
 	 */
 	local_paca->irq_happened &= ~PACA_IRQ_DEC;
-	if (decrementer_check_overflow())
+	if ((happened & PACA_IRQ_DEC) || decrementer_check_overflow())
 		return 0x900;

 	/* Finally check if an external interrupt happened */
--
1.8.1.2