The patch titled
Subject: sparc: implement watchdog_nmi_enable and watchdog_nmi_disable
has been added to the -mm tree. Its filename is
sparc-implement-watchdog_nmi_enable-and-watchdog_nmi_disable.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/sparc-implement-watchdog_nmi_enable-and-watchdog_nmi_disable.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/sparc-implement-watchdog_nmi_enable-and-watchdog_nmi_disable.patch
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------------------------------------------------------
From: Babu Moger <babu.moger@xxxxxxxxxx>
Subject: sparc: implement watchdog_nmi_enable and watchdog_nmi_disable
Implement functions watchdog_nmi_enable and watchdog_nmi_disable to
enable/disable nmi watchdog. Sparc uses arch specific nmi watchdog
handler. Currently, we do not have a way to enable/disable nmi watchdog
dynamically. With these patches we can enable or disable arch specific
nmi watchdogs using proc or sysctl interface.
Example commands.
To enable: echo 1 > /proc/sys/kernel/nmi_watchdog
To disable: echo 0 > /proc/sys/kernel/nmi_watchdog
It can also achieved using the sysctl parameter kernel.nmi_watchdog
Link: http://lkml.kernel.org/r/1478034826-43888-4-git-send-email-babu.moger@xxxxxxxxxx
Signed-off-by: Babu Moger <babu.moger@xxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Jiri Kosina <jkosina@xxxxxxx>
Cc: Andi Kleen <andi@xxxxxxxxxxxxxx>
Cc: Yaowei Bai <baiyaowei@xxxxxxxxxxxxxxxxxxxx>
Cc: Don Zickus <dzickus@xxxxxxxxxx>
Cc: Aaron Tomlin <atomlin@xxxxxxxxxx>
Cc: Ulrich Obergfell <uobergfe@xxxxxxxxxx>
Cc: Tejun Heo <tj@xxxxxxxxxx>
Cc: Hidehiro Kawai <hidehiro.kawai.ez@xxxxxxxxxxx>
Cc: Josh Hunt <johunt@xxxxxxxxxx>
Cc: "David S. Miller" <davem@xxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
arch/sparc/kernel/nmi.c | 44 +++++++++++++++++++++++++++++++++++++-
1 file changed, 43 insertions(+), 1 deletion(-)
diff -puN arch/sparc/kernel/nmi.c~sparc-implement-watchdog_nmi_enable-and-watchdog_nmi_disable arch/sparc/kernel/nmi.c
--- a/arch/sparc/kernel/nmi.c~sparc-implement-watchdog_nmi_enable-and-watchdog_nmi_disable
+++ a/arch/sparc/kernel/nmi.c
@@ -42,7 +42,7 @@ static int panic_on_timeout;
*/
atomic_t nmi_active = ATOMIC_INIT(0); /* oprofile uses this */
EXPORT_SYMBOL(nmi_active);
-
+static int nmi_init_done;
static unsigned int nmi_hz = HZ;
static DEFINE_PER_CPU(short, wd_enabled);
static int endflag __initdata;
@@ -153,6 +153,8 @@ static void report_broken_nmi(int cpu, i
void stop_nmi_watchdog(void *unused)
{
+ if (!__this_cpu_read(wd_enabled))
+ return;
pcr_ops->write_pcr(0, pcr_ops->pcr_nmi_disable);
__this_cpu_write(wd_enabled, 0);
atomic_dec(&nmi_active);
@@ -207,6 +209,9 @@ error:
void start_nmi_watchdog(void *unused)
{
+ if (__this_cpu_read(wd_enabled))
+ return;
+
__this_cpu_write(wd_enabled, 1);
atomic_inc(&nmi_active);
@@ -259,6 +264,8 @@ int __init nmi_init(void)
}
}
+ nmi_init_done = 1;
+
return err;
}
@@ -270,3 +277,38 @@ static int __init setup_nmi_watchdog(cha
return 0;
}
__setup("nmi_watchdog=", setup_nmi_watchdog);
+
+/*
+ * sparc specific NMI watchdog enable function.
+ * Enables watchdog if it is not enabled already.
+ */
+int watchdog_nmi_enable(unsigned int cpu)
+{
+ if (atomic_read(&nmi_active) == -1) {
+ pr_warn("NMI watchdog cannot be enabled or disabled\n");
+ return -1;
+ }
+
+ /*
+ * watchdog thread could start even before nmi_init is called.
+ * Just Return in that case. Let nmi_init finish the init
+ * process first.
+ */
+ if (!nmi_init_done)
+ return 0;
+
+ smp_call_function_single(cpu, start_nmi_watchdog, NULL, 1);
+
+ return 0;
+}
+/*
+ * sparc specific NMI watchdog disable function.
+ * Disables watchdog if it is not disabled already.
+ */
+void watchdog_nmi_disable(unsigned int cpu)
+{
+ if (atomic_read(&nmi_active) == -1)
+ pr_warn_once("NMI watchdog cannot be enabled or disabled\n");
+ else
+ smp_call_function_single(cpu, stop_nmi_watchdog, NULL, 1);
+}
_
Patches currently in -mm which might be from babu.moger@xxxxxxxxxx are
watchdog-move-shared-definitions-to-nmih.patch
watchdog-move-hardlockup-detector-to-separate-file.patch
sparc-implement-watchdog_nmi_enable-and-watchdog_nmi_disable.patch
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