From: George Beshers <gbeshers@redhat.com>
Date: Thu, 31 Jul 2008 15:34:05 -0400
Subject: [IA64] Disable/re-enable CPE interrupts on Altix
Message-id: 20080731192810.4411.18140.sendpatchset@dhcp-100-2-194.bos.redhat.com
O-Subject: [RHEL5.3 PATCH 17/19] [IA64] Disable/re-enable CPE interrupts on Altix
Bugzilla: 455308
RH-Acked-by: Prarit Bhargava <prarit@redhat.com>

[IA64] Disable/re-enable CPE interrupts on Altix

BZ#455308

Upstream: http://git.kernel.org/?p=linux/kernel/git/aegl/linux-2.6.git;a=commitdiff;h=1f3b6045f783ee394076ad6dba2d72ecaaecd243

When the CPE handler encounters too many CPEs (such as a solid single
bit memory error), it sets up a polling timer and disables the CPE
interrupt (to avoid excessive overhead logging the stream of single
bit errors).  disable_irq_nosync() calls chip->disable() to provide
a chipset specifiec interface for disabling the interrupt.  This patch
adds the Altix specific support to disable and re-enable the CPE interrupt.

Signed-off-by: Russ Anderson (rja@sgi.com)

diff --git a/arch/ia64/kernel/mca.c b/arch/ia64/kernel/mca.c
index 1350dd8..c666582 100644
--- a/arch/ia64/kernel/mca.c
+++ b/arch/ia64/kernel/mca.c
@@ -568,7 +568,7 @@ out:
  *  Outputs
  *      None
  */
-static void
+void
 ia64_mca_register_cpev (int cpev)
 {
 	/* Register the CPE interrupt vector with SAL */
diff --git a/arch/ia64/sn/kernel/irq.c b/arch/ia64/sn/kernel/irq.c
index bf67369..5654bfc 100644
--- a/arch/ia64/sn/kernel/irq.c
+++ b/arch/ia64/sn/kernel/irq.c
@@ -5,7 +5,7 @@
  * License.  See the file "COPYING" in the main directory of this archive
  * for more details.
  *
- * Copyright (c) 2000-2006 Silicon Graphics, Inc.  All Rights Reserved.
+ * Copyright (c) 2000-2007 Silicon Graphics, Inc.  All Rights Reserved.
  */
 
 #include <linux/irq.h>
@@ -68,12 +68,18 @@ static void sn_shutdown_irq(unsigned int irq)
 {
 }
 
+extern void ia64_mca_register_cpev(int);
+
 static void sn_disable_irq(unsigned int irq)
 {
+	if (irq == local_vector_to_irq(IA64_CPE_VECTOR))
+		ia64_mca_register_cpev(0);
 }
 
 static void sn_enable_irq(unsigned int irq)
 {
+	if (irq == local_vector_to_irq(IA64_CPE_VECTOR))
+		ia64_mca_register_cpev(irq);
 }
 
 static void sn_ack_irq(unsigned int irq)