[RFC PATCH 3/4] watchdog: Move hardlockup detector to separate file

[Babu Moger]

Move hardlockup detector code to watchdog_hld.c.
Also update the makefile accordigly.

Signed-off-by: Babu Moger 
---
 kernel/Makefile   |1 +
 kernel/watchdog_hld.c |  238 +
 2 files changed, 239 insertions(+), 0 deletions(-)
 create mode 100644 kernel/watchdog_hld.c

diff --git a/kernel/Makefile b/kernel/Makefile
index eb26e12..314e7d6 100644
--- a/kernel/Makefile
+++ b/kernel/Makefile
@@ -84,6 +84,7 @@ obj-$(CONFIG_KPROBES) += kprobes.o
 obj-$(CONFIG_KGDB) += debug/
 obj-$(CONFIG_DETECT_HUNG_TASK) += hung_task.o
 obj-$(CONFIG_LOCKUP_DETECTOR) += watchdog.o
+obj-$(CONFIG_HARDLOCKUP_DETECTOR) += watchdog_hld.o
 obj-$(CONFIG_SECCOMP) += seccomp.o
 obj-$(CONFIG_RELAY) += relay.o
 obj-$(CONFIG_SYSCTL) += utsname_sysctl.o
diff --git a/kernel/watchdog_hld.c b/kernel/watchdog_hld.c
new file mode 100644
index 000..cd690fb
--- /dev/null
+++ b/kernel/watchdog_hld.c
@@ -0,0 +1,238 @@
+/*
+ * Detect hard and soft lockups on a system
+ *
+ * started by Don Zickus, Copyright (C) 2010 Red Hat, Inc.
+ *
+ * Note: Most of this code is borrowed heavily from the original softlockup
+ * detector, so thanks to Ingo for the initial implementation.
+ * Some chunks also taken from the old x86-specific nmi watchdog code, thanks
+ * to those contributors as well.
+ */
+
+#include 
+#include 
+#include 
+#include 
+
+static DEFINE_PER_CPU(bool, hard_watchdog_warn);
+static DEFINE_PER_CPU(bool, watchdog_nmi_touch);
+static DEFINE_PER_CPU(unsigned long, hrtimer_interrupts_saved);
+static DEFINE_PER_CPU(struct perf_event *, watchdog_ev);
+
+/* boot commands */
+/*
+ * Should we panic when a soft-lockup or hard-lockup occurs:
+ */
+unsigned int __read_mostly hardlockup_panic =
+   CONFIG_BOOTPARAM_HARDLOCKUP_PANIC_VALUE;
+static unsigned long hardlockup_allcpu_dumped;
+/*
+ * We may not want to enable hard lockup detection by default in all cases,
+ * for example when running the kernel as a guest on a hypervisor. In these
+ * cases this function can be called to disable hard lockup detection. This
+ * function should only be executed once by the boot processor before the
+ * kernel command line parameters are parsed, because otherwise it is not
+ * possible to override this in hardlockup_panic_setup().
+ */
+void hardlockup_detector_disable(void)
+{
+   watchdog_enabled &= ~NMI_WATCHDOG_ENABLED;
+}
+
+static int __init hardlockup_panic_setup(char *str)
+{
+   if (!strncmp(str, "panic", 5))
+   hardlockup_panic = 1;
+   else if (!strncmp(str, "nopanic", 7))
+   hardlockup_panic = 0;
+   else if (!strncmp(str, "0", 1))
+   watchdog_enabled &= ~NMI_WATCHDOG_ENABLED;
+   else if (!strncmp(str, "1", 1))
+   watchdog_enabled |= NMI_WATCHDOG_ENABLED;
+   return 1;
+}
+__setup("nmi_watchdog=", hardlockup_panic_setup);
+
+void touch_nmi_watchdog(void)
+{
+   /*
+* Using __raw here because some code paths have
+* preemption enabled.  If preemption is enabled
+* then interrupts should be enabled too, in which
+* case we shouldn't have to worry about the watchdog
+* going off.
+*/
+   raw_cpu_write(watchdog_nmi_touch, true);
+   touch_softlockup_watchdog();
+}
+EXPORT_SYMBOL(touch_nmi_watchdog);
+
+/* watchdog detector functions */
+static bool is_hardlockup(void)
+{
+   unsigned long hrint = __this_cpu_read(hrtimer_interrupts);
+
+   if (__this_cpu_read(hrtimer_interrupts_saved) == hrint)
+   return true;
+
+   __this_cpu_write(hrtimer_interrupts_saved, hrint);
+   return false;
+}
+
+static struct perf_event_attr wd_hw_attr = {
+   .type   = PERF_TYPE_HARDWARE,
+   .config = PERF_COUNT_HW_CPU_CYCLES,
+   .size   = sizeof(struct perf_event_attr),
+   .pinned = 1,
+   .disabled   = 1,
+};
+
+/* Callback function for perf event subsystem */
+static void watchdog_overflow_callback(struct perf_event *event,
+struct perf_sample_data *data,
+struct pt_regs *regs)
+{
+   /* Ensure the watchdog never gets throttled */
+   event->hw.interrupts = 0;
+
+   if (__this_cpu_read(watchdog_nmi_touch) == true) {
+   __this_cpu_write(watchdog_nmi_touch, false);
+   return;
+   }
+
+   /* check for a hardlockup
+* This is done by making sure our timer interrupt
+* is incrementing.  The timer interrupt should have
+* fired multiple times before we overflow'd.  If it hasn't
+* then this is a good indication the cpu is stuck
+*/
+   if (is_hardlockup()) {
+   int this_cpu = smp_processor_id();
+   struct pt_regs *regs = get_irq_regs();
+
+   /* only print hardlockups once */
+   if (__this_cpu_read(hard_watchdog_warn) == true)
+   return;
+
+   

[RFC PATCH 3/4] watchdog: Move hardlockup detector to separate file

[Babu Moger]

Move hardlockup detector code to watchdog_hld.c.
Also update the makefile accordigly.

Signed-off-by: Babu Moger 
---
 kernel/Makefile   |1 +
 kernel/watchdog_hld.c |  238 +
 2 files changed, 239 insertions(+), 0 deletions(-)
 create mode 100644 kernel/watchdog_hld.c

diff --git a/kernel/Makefile b/kernel/Makefile
index eb26e12..314e7d6 100644
--- a/kernel/Makefile
+++ b/kernel/Makefile
@@ -84,6 +84,7 @@ obj-$(CONFIG_KPROBES) += kprobes.o
 obj-$(CONFIG_KGDB) += debug/
 obj-$(CONFIG_DETECT_HUNG_TASK) += hung_task.o
 obj-$(CONFIG_LOCKUP_DETECTOR) += watchdog.o
+obj-$(CONFIG_HARDLOCKUP_DETECTOR) += watchdog_hld.o
 obj-$(CONFIG_SECCOMP) += seccomp.o
 obj-$(CONFIG_RELAY) += relay.o
 obj-$(CONFIG_SYSCTL) += utsname_sysctl.o
diff --git a/kernel/watchdog_hld.c b/kernel/watchdog_hld.c
new file mode 100644
index 000..cd690fb
--- /dev/null
+++ b/kernel/watchdog_hld.c
@@ -0,0 +1,238 @@
+/*
+ * Detect hard and soft lockups on a system
+ *
+ * started by Don Zickus, Copyright (C) 2010 Red Hat, Inc.
+ *
+ * Note: Most of this code is borrowed heavily from the original softlockup
+ * detector, so thanks to Ingo for the initial implementation.
+ * Some chunks also taken from the old x86-specific nmi watchdog code, thanks
+ * to those contributors as well.
+ */
+
+#include 
+#include 
+#include 
+#include 
+
+static DEFINE_PER_CPU(bool, hard_watchdog_warn);
+static DEFINE_PER_CPU(bool, watchdog_nmi_touch);
+static DEFINE_PER_CPU(unsigned long, hrtimer_interrupts_saved);
+static DEFINE_PER_CPU(struct perf_event *, watchdog_ev);
+
+/* boot commands */
+/*
+ * Should we panic when a soft-lockup or hard-lockup occurs:
+ */
+unsigned int __read_mostly hardlockup_panic =
+   CONFIG_BOOTPARAM_HARDLOCKUP_PANIC_VALUE;
+static unsigned long hardlockup_allcpu_dumped;
+/*
+ * We may not want to enable hard lockup detection by default in all cases,
+ * for example when running the kernel as a guest on a hypervisor. In these
+ * cases this function can be called to disable hard lockup detection. This
+ * function should only be executed once by the boot processor before the
+ * kernel command line parameters are parsed, because otherwise it is not
+ * possible to override this in hardlockup_panic_setup().
+ */
+void hardlockup_detector_disable(void)
+{
+   watchdog_enabled &= ~NMI_WATCHDOG_ENABLED;
+}
+
+static int __init hardlockup_panic_setup(char *str)
+{
+   if (!strncmp(str, "panic", 5))
+   hardlockup_panic = 1;
+   else if (!strncmp(str, "nopanic", 7))
+   hardlockup_panic = 0;
+   else if (!strncmp(str, "0", 1))
+   watchdog_enabled &= ~NMI_WATCHDOG_ENABLED;
+   else if (!strncmp(str, "1", 1))
+   watchdog_enabled |= NMI_WATCHDOG_ENABLED;
+   return 1;
+}
+__setup("nmi_watchdog=", hardlockup_panic_setup);
+
+void touch_nmi_watchdog(void)
+{
+   /*
+* Using __raw here because some code paths have
+* preemption enabled.  If preemption is enabled
+* then interrupts should be enabled too, in which
+* case we shouldn't have to worry about the watchdog
+* going off.
+*/
+   raw_cpu_write(watchdog_nmi_touch, true);
+   touch_softlockup_watchdog();
+}
+EXPORT_SYMBOL(touch_nmi_watchdog);
+
+/* watchdog detector functions */
+static bool is_hardlockup(void)
+{
+   unsigned long hrint = __this_cpu_read(hrtimer_interrupts);
+
+   if (__this_cpu_read(hrtimer_interrupts_saved) == hrint)
+   return true;
+
+   __this_cpu_write(hrtimer_interrupts_saved, hrint);
+   return false;
+}
+
+static struct perf_event_attr wd_hw_attr = {
+   .type   = PERF_TYPE_HARDWARE,
+   .config = PERF_COUNT_HW_CPU_CYCLES,
+   .size   = sizeof(struct perf_event_attr),
+   .pinned = 1,
+   .disabled   = 1,
+};
+
+/* Callback function for perf event subsystem */
+static void watchdog_overflow_callback(struct perf_event *event,
+struct perf_sample_data *data,
+struct pt_regs *regs)
+{
+   /* Ensure the watchdog never gets throttled */
+   event->hw.interrupts = 0;
+
+   if (__this_cpu_read(watchdog_nmi_touch) == true) {
+   __this_cpu_write(watchdog_nmi_touch, false);
+   return;
+   }
+
+   /* check for a hardlockup
+* This is done by making sure our timer interrupt
+* is incrementing.  The timer interrupt should have
+* fired multiple times before we overflow'd.  If it hasn't
+* then this is a good indication the cpu is stuck
+*/
+   if (is_hardlockup()) {
+   int this_cpu = smp_processor_id();
+   struct pt_regs *regs = get_irq_regs();
+
+   /* only print hardlockups once */
+   if (__this_cpu_read(hard_watchdog_warn) == true)
+   return;
+
+   pr_emerg("Watchdog detected hard