[PATCH 48/45] sparc64: Fix reset hangs on Niagara systems.

From: Chris Wright <chrisw@sous-sol.org>
To: Chris Wright <chrisw@sous-sol.org>
Cc: linux-kernel@vger.kernel.org, stable@kernel.org,
	"Theodore Ts'o" <tytso@mit.edu>,
	Zwane Mwaikambo <zwane@arm.linux.org.uk>,
	Eugene Teo <eteo@redhat.com>,
	Justin Forbes <jmforbes@linuxtx.org>,
	Domenico Andreoli <cavokz@gmail.com>,
	Chris Wedgwood <reviews@ml.cw.f00f.org>, Jake Edge <jake@lwn.net>,
	Randy Dunlap <rdunlap@xenotime.net>,
	Michael Krufky <mkrufky@linuxtv.org>,
	alan@lxorguk.ukuu.org.uk, Chuck Ebbert <cebbert@redhat.com>,
	Dave Jones <davej@redhat.com>,
	Chuck Wolber <chuckw@quantumlinux.com>,
	akpm@linux-foundation.org, torvalds@linux-foundation.org,
	Willy Tarreau <w@1wt.eu>,
	Rodrigo Rubira Branco <rbranco@la.checkpoint.com>,
	davem@davemloft.net
Subject: [PATCH 48/45] sparc64: Fix reset hangs on Niagara systems.
Date: Wed, 1 Apr 2009 23:58:05 -0700	[thread overview]
Message-ID: <20090402065805.GD18394@sequoia.sous-sol.org> (raw)
In-Reply-To: <20090331231045.719396245@sous-sol.org>

-stable review patch.  If anyone has any objections, please let us know.
---------------------

From: David S. Miller <davem@davemloft.net>

[ Upstream commit ffaba674090f287afe0c44fd8d978c64c03581a8 ]

Hypervisor versions older than version 1.6.1 cannot handle
leaving the profile counter overflow interrupt chirping
when the system does a soft reset.

So use a reboot notifier to shut off the NMI watchdog.

Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Chris Wright <chrisw@sous-sol.org>
---
 arch/sparc/kernel/nmi.c |   23 ++++++++++++++++++++++-
 1 file changed, 22 insertions(+), 1 deletion(-)

--- a/arch/sparc/kernel/nmi.c
+++ b/arch/sparc/kernel/nmi.c
@@ -13,6 +13,7 @@
 #include <linux/module.h>
 #include <linux/kprobes.h>
 #include <linux/kernel_stat.h>
+#include <linux/reboot.h>
 #include <linux/slab.h>
 #include <linux/kdebug.h>
 #include <linux/delay.h>
@@ -206,13 +207,33 @@ void nmi_adjust_hz(unsigned int new_hz)
 }
 EXPORT_SYMBOL_GPL(nmi_adjust_hz);
 
+static int nmi_shutdown(struct notifier_block *nb, unsigned long cmd, void *p)
+{
+	on_each_cpu(stop_watchdog, NULL, 1);
+	return 0;
+}
+
+static struct notifier_block nmi_reboot_notifier = {
+	.notifier_call = nmi_shutdown,
+};
+
 int __init nmi_init(void)
 {
+	int err;
+
 	nmi_usable = 1;
 
 	on_each_cpu(start_watchdog, NULL, 1);
 
-	return check_nmi_watchdog();
+	err = check_nmi_watchdog();
+	if (!err) {
+		err = register_reboot_notifier(&nmi_reboot_notifier);
+		if (err) {
+			nmi_usable = 0;
+			on_each_cpu(stop_watchdog, NULL, 1);
+		}
+	}
+	return err;
 }
 
 static int __init setup_nmi_watchdog(char *str)
