[PATCH 1/2] reboot: Introduce emergency poweroff function

From: Keerthy
Date: Thu Jan 28 2016 - 08:06:58 EST


emergency_poweroff function can be called in critical situations
to poweroff the system after a configurable period of time. The
default value of the delay is 0 triggers system poweroff immediately.

Signed-off-by: Keerthy <j-keerthy@xxxxxx>
Suggested-by: Ingo Molnar <mingo@xxxxxxxxxx>
Reported-by: Nishanth Menon <nm@xxxxxx>
---
arch/Kconfig | 9 +++++++++
include/linux/reboot.h | 1 +
kernel/reboot.c | 31 +++++++++++++++++++++++++++++++
3 files changed, 41 insertions(+)

diff --git a/arch/Kconfig b/arch/Kconfig
index f6b649d..0962ea7 100644
--- a/arch/Kconfig
+++ b/arch/Kconfig
@@ -37,6 +37,15 @@ config OPROFILE_NMI_TIMER
def_bool y
depends on PERF_EVENTS && HAVE_PERF_EVENTS_NMI && !PPC64

+config EMERGENCY_POWEROFF_DELAY_MS
+ int "Emergency poweroff delay in milli-seconds"
+ default 0
+ help
+ The number of milliseconds to delay before emergency
+ poweroff kicks in.
+
+ If set to 0 poweroff will happen immediately.
+
config KPROBES
bool "Kprobes"
depends on MODULES
diff --git a/include/linux/reboot.h b/include/linux/reboot.h
index a7ff409..108b4ce 100644
--- a/include/linux/reboot.h
+++ b/include/linux/reboot.h
@@ -71,6 +71,7 @@ void ctrl_alt_del(void);
extern char poweroff_cmd[POWEROFF_CMD_PATH_LEN];

extern void orderly_poweroff(bool force);
+extern void emergency_poweroff(void);
extern void orderly_reboot(void);

/*
diff --git a/kernel/reboot.c b/kernel/reboot.c
index bd30a97..def195b 100644
--- a/kernel/reboot.c
+++ b/kernel/reboot.c
@@ -469,6 +469,37 @@ void orderly_poweroff(bool force)
}
EXPORT_SYMBOL_GPL(orderly_poweroff);

+/**
+ * emergency_poweroff_func - emergency poweroff work after a known delay
+ * @work: work_struct associated with the emergency poweroff function
+ *
+ * This function is called in very critical situations to force
+ * a kernel poweroff after a configurable timeout value.
+ */
+static void emergency_poweroff_func(struct work_struct *work)
+{
+ pr_warn("Attempting kernel_power_off\n");
+ kernel_power_off();
+
+ pr_warn("kernel_power_off has failed! Attempting emergency_restart\n");
+ emergency_restart();
+}
+
+static DECLARE_DELAYED_WORK(emergency_poweroff_work, emergency_poweroff_func);
+
+/**
+ * emergency_poweroff - Trigger an emergency system poweroff
+ *
+ * This may be called from any critical situation to trigger a system shutdown
+ * after a known period of time. By default the delay is 0 millisecond
+ */
+void emergency_poweroff(void)
+{
+ schedule_delayed_work(&emergency_poweroff_work,
+ msecs_to_jiffies(CONFIG_EMERGENCY_POWEROFF_DELAY_MS));
+}
+EXPORT_SYMBOL_GPL(emergency_poweroff);
+
static void reboot_work_func(struct work_struct *work)
{
__orderly_reboot();
--
1.9.1