+/**
+ * kernel_kexec - reboot the system
+ *
+ * Move into place and start executing a preloaded standalone
+ * executable. If nothing was preloaded return an error.
+ */
+void kernel_kexec(void)
+{
+#ifdef CONFIG_KEXEC
+ struct kimage *image;
+ image = xchg(&kexec_image, NULL);
+ if (!image) {
+ return;
+ }
+ kernel_restart_prepare(NULL);
+ printk(KERN_EMERG "Starting new kernel\n");
+ machine_shutdown();
+ machine_kexec(image);
+#endif
+}
+EXPORT_SYMBOL_GPL(kernel_kexec);
+
+void kernel_shutdown_prepare(enum system_states state)
+{
+ notifier_call_chain(&reboot_notifier_list,
+ (state == SYSTEM_HALT)?SYS_HALT:SYS_POWER_OFF, NULL);
+ system_state = state;
+ device_shutdown();
+}
+/**
+ * kernel_halt - halt the system
+ *
+ * Shutdown everything and perform a clean system halt.
+ */
+void kernel_halt(void)
+{
+ kernel_shutdown_prepare(SYSTEM_HALT);
+ printk(KERN_EMERG "System halted.\n");
+ machine_halt();
+}
+
+EXPORT_SYMBOL_GPL(kernel_halt);
+
+/**
+ * kernel_power_off - power_off the system
+ *
+ * Shutdown everything and perform a clean system power_off.
+ */
+void kernel_power_off(void)
+{
+ kernel_shutdown_prepare(SYSTEM_POWER_OFF);
+ printk(KERN_EMERG "Power down.\n");
+ machine_power_off();
+}
+EXPORT_SYMBOL_GPL(kernel_power_off);