[ 3.5.y.z extended stable ] Patch "Fix initialization of CMCI/CMCP interrupts" has been added to staging queue

[Luis Henriques]

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

    Fix initialization of CMCI/CMCP interrupts

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 06ece44c3b3689af1d82609a26450ecb16d9f04e Mon Sep 17 00:00:00 2001
From: Tony Luck <tony.luck at intel.com>
Date: Wed, 20 Mar 2013 10:30:15 -0700
Subject: [PATCH] Fix initialization of CMCI/CMCP interrupts

commit d303e9e98fce56cdb3c6f2ac92f626fc2bd51c77 upstream.

Back 2010 during a revamp of the irq code some initializations
were moved from ia64_mca_init() to ia64_mca_late_init() in

	commit c75f2aa13f5b268aba369b5dc566088b5194377c
	Cannot use register_percpu_irq() from ia64_mca_init()

But this was hideously wrong. First of all these initializations
are now down far too late. Specifically after all the other cpus
have been brought up and initialized their own CMC vectors from
smp_callin(). Also ia64_mca_late_init() may be called from any cpu
so the line:
	ia64_mca_cmc_vector_setup();       /* Setup vector on BSP */
is generally not executed on the BSP, and so the CMC vector isn't
setup at all on that processor.

Make use of the arch_early_irq_init() hook to get this code executed
at just the right moment: not too early, not too late.

Reported-by: Fred Hartnett <fred.hartnett at hp.com>
Tested-by: Fred Hartnett <fred.hartnett at hp.com>
Signed-off-by: Tony Luck <tony.luck at intel.com>
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
 arch/ia64/include/asm/mca.h |  1 +
 arch/ia64/kernel/irq.c      |  8 ++++++++
 arch/ia64/kernel/mca.c      | 37 ++++++++++++++++++++++++-------------
 3 files changed, 33 insertions(+), 13 deletions(-)

diff --git a/arch/ia64/include/asm/mca.h b/arch/ia64/include/asm/mca.h
index 43f96ab..8c70961 100644
--- a/arch/ia64/include/asm/mca.h
+++ b/arch/ia64/include/asm/mca.h
@@ -143,6 +143,7 @@ extern unsigned long __per_cpu_mca[NR_CPUS];
 extern int cpe_vector;
 extern int ia64_cpe_irq;
 extern void ia64_mca_init(void);
+extern void ia64_mca_irq_init(void);
 extern void ia64_mca_cpu_init(void *);
 extern void ia64_os_mca_dispatch(void);
 extern void ia64_os_mca_dispatch_end(void);
diff --git a/arch/ia64/kernel/irq.c b/arch/ia64/kernel/irq.c
index ad69606..f2c41828 100644
--- a/arch/ia64/kernel/irq.c
+++ b/arch/ia64/kernel/irq.c
@@ -23,6 +23,8 @@
 #include <linux/interrupt.h>
 #include <linux/kernel_stat.h>

+#include <asm/mca.h>
+
 /*
  * 'what should we do if we get a hw irq event on an illegal vector'.
  * each architecture has to answer this themselves.
@@ -83,6 +85,12 @@ bool is_affinity_mask_valid(const struct cpumask *cpumask)

 #endif /* CONFIG_SMP */

+int __init arch_early_irq_init(void)
+{
+	ia64_mca_irq_init();
+	return 0;
+}
+
 #ifdef CONFIG_HOTPLUG_CPU
 unsigned int vectors_in_migration[NR_IRQS];

diff --git a/arch/ia64/kernel/mca.c b/arch/ia64/kernel/mca.c
index 65bf9cd..d7396db 100644
--- a/arch/ia64/kernel/mca.c
+++ b/arch/ia64/kernel/mca.c
@@ -2074,22 +2074,16 @@ ia64_mca_init(void)
 	printk(KERN_INFO "MCA related initialization done\n");
 }

+
 /*
- * ia64_mca_late_init
- *
- *	Opportunity to setup things that require initialization later
- *	than ia64_mca_init.  Setup a timer to poll for CPEs if the
- *	platform doesn't support an interrupt driven mechanism.
- *
- *  Inputs  :   None
- *  Outputs :   Status
+ * These pieces cannot be done in ia64_mca_init() because it is called before
+ * early_irq_init() which would wipe out our percpu irq registrations. But we
+ * cannot leave them until ia64_mca_late_init() because by then all the other
+ * processors have been brought online and have set their own CMC vectors to
+ * point at a non-existant action. Called from arch_early_irq_init().
  */
-static int __init
-ia64_mca_late_init(void)
+void __init ia64_mca_irq_init(void)
 {
-	if (!mca_init)
-		return 0;
-
 	/*
 	 *  Configure the CMCI/P vector and handler. Interrupts for CMC are
 	 *  per-processor, so AP CMC interrupts are setup in smp_callin() (smpboot.c).
@@ -2108,6 +2102,23 @@ ia64_mca_late_init(void)
 	/* Setup the CPEI/P handler */
 	register_percpu_irq(IA64_CPEP_VECTOR, &mca_cpep_irqaction);
 #endif
+}
+
+/*
+ * ia64_mca_late_init
+ *
+ *	Opportunity to setup things that require initialization later
+ *	than ia64_mca_init.  Setup a timer to poll for CPEs if the
+ *	platform doesn't support an interrupt driven mechanism.
+ *
+ *  Inputs  :   None
+ *  Outputs :   Status
+ */
+static int __init
+ia64_mca_late_init(void)
+{
+	if (!mca_init)
+		return 0;

 	register_hotcpu_notifier(&mca_cpu_notifier);

--
1.8.1.2