1 // SPDX-License-Identifier: GPL-2.0+
5  * A watchdog timer based upon the IPMI interface.
43  * This is ugly, but I've determined that x86 is the only architecture
57  * The IPMI command/response information for the watchdog timer.
98  * pre-timeout in seconds.
109  * Setting/getting the watchdog timer value.  This is for bytes 5 and
135 /* The pre-timeout is disabled by default. */
160 static int ifnum_to_use = -1;
184 		return -EINVAL;  in set_param_timeout()
187 		return -EINVAL;  in set_param_timeout()
189 	*((int *)kp->arg) = l;  in set_param_timeout()
211 	action_fn  fn = (action_fn) kp->arg;  in set_param_str()
234 	action_fn fn = (action_fn) kp->arg;  in get_param_str()
276 		 "timer.  Setting to -1 defaults to the first registered "
289 MODULE_PARM_DESC(action, "Timeout action. One of: "
293 MODULE_PARM_DESC(preaction, "Pretimeout action.  One of: "
297 MODULE_PARM_DESC(preop, "Pretimeout driver operation.  One of: "
308 /* Default state of the timer. */
311 /* Is someone using the watchdog?  Only one user is allowed. */
316  * start the timer.  The timer doesn't normally run when the driver is
326 /* If a pretimeout occurs, this is used to allow only one panic to happen. */
327 static atomic_t preop_panic_excl = ATOMIC_INIT(-1);
337  * We use a mutex to make sure that only one thing can send a set a
338  * message at one time.  The mutex is claimed when a message is sent
377 			/* This is an IPMI 1.5-only feature. */  in __ipmi_set_timeout()
381 			 * In ipmi 1.0, setting the timer stops the watchdog, we  in __ipmi_set_timeout()
434 		return -ENODEV;  in _ipmi_set_timeout()
471 	 * Don't reset the timer if we have the timer turned off, that  in panic_halt_ipmi_heartbeat()
472 	 * re-enables the watchdog.  in panic_halt_ipmi_heartbeat()
490  * Special call, doesn't claim any locks.  This is only to be called
491  * at panic or halt time, in run-to-completion mode, when the caller
492  * is the only CPU and the only thing that will be going is these IPMI
518 	 * Don't reset the timer if we have the timer turned off, that  in __ipmi_heartbeat()
519 	 * re-enables the watchdog.  in __ipmi_heartbeat()
555 			rv = -EIO;  in __ipmi_heartbeat()
560 		 * The timer was not initialized, that means the BMC was  in __ipmi_heartbeat()
562 		 * to restore the timer's info.  Note that we still hold  in __ipmi_heartbeat()
581 		rv = -EINVAL;  in __ipmi_heartbeat()
593 		return -ENODEV;  in _ipmi_heartbeat()
641 		return i ? -EFAULT : 0;  in ipmi_ioctl()
646 			return -EFAULT;  in ipmi_ioctl()
653 			return -EFAULT;  in ipmi_ioctl()
659 			return -EFAULT;  in ipmi_ioctl()
666 			return -EFAULT;  in ipmi_ioctl()
675 			return -EFAULT;  in ipmi_ioctl()
692 			return -EFAULT;  in ipmi_ioctl()
696 		return -ENOIOCTLCMD;  in ipmi_ioctl()
731 					return -EFAULT;  in ipmi_write()
755 	 * Reading returns if the pretimeout has gone off, and it only does  in ipmi_read()
760 		if (file->f_flags & O_NONBLOCK) {  in ipmi_read()
761 			rv = -EAGAIN;  in ipmi_read()
776 			rv = -ERESTARTSYS;  in ipmi_read()
787 			rv = -EFAULT;  in ipmi_read()
800 			return -EBUSY;  in ipmi_open()
804 		 * Don't start the timer now, let it start on the  in ipmi_open()
811 		return (-ENODEV);  in ipmi_open()
879 	if (msg->msg.cmd == IPMI_WDOG_RESET_TIMER &&  in ipmi_wdog_msg_handler()
880 			msg->msg.data[0] == IPMI_WDOG_TIMER_NOT_INIT_RESP)  in ipmi_wdog_msg_handler()
881 …he IPMI controller appears to have been reset, will attempt to reinitialize the watchdog timer\n");  in ipmi_wdog_msg_handler()
882 	else if (msg->msg.data[0] != 0)  in ipmi_wdog_msg_handler()
884 		       msg->msg.data[0],  in ipmi_wdog_msg_handler()
885 		       msg->msg.cmd);  in ipmi_wdog_msg_handler()
895 				panic("Watchdog pre-timeout");  in ipmi_wdog_pretimeout_handler()
907 	 * work unless we re-enable the timer.  So do so.  in ipmi_wdog_pretimeout_handler()
918 	 * the watchdog timer to a reasonable value to complete the  in ipmi_wdog_panic_handler()
919 	 * panic, if the watchdog timer is running.  Plus the  in ipmi_wdog_panic_handler()
924 		/* Make sure we do this only once. */  in ipmi_wdog_panic_handler()
941 	int rv = -EBUSY;  in ipmi_register_watchdog()
981 		 * ourselves plenty of time to stop the timer.  in ipmi_register_watchdog()
992 			pr_warn("Error starting timer to test NMI: 0x%x.  The NMI pretimeout will likely not work\n",  in ipmi_register_watchdog()
1013 		/* Run from startup, so start the timer now. */  in ipmi_register_watchdog()
1019 		/* Stop the timer now. */  in ipmi_register_watchdog()
1035 	/* Make sure no one can call us any more. */  in ipmi_unregister_watchdog()
1083 	 * If no one else handled the NMI, we assume it was the IPMI  in ipmi_nmi()
1088 		   an error and not work unless we re-enable  in ipmi_nmi()
1089 		   the timer.   So do so. */  in ipmi_nmi()
1092 			nmi_panic(regs, "pre-timeout");  in ipmi_nmi()
1106 		/* Make sure we only do this once. */  in wdog_reboot_handler()
1114 			/* Set a long timer to let the reboot happen or  in wdog_reboot_handler()
1115 			   reset if it hangs, but only if the watchdog  in wdog_reboot_handler()
1116 			   timer was already running. */  in wdog_reboot_handler()
1160 		return -EINVAL;  in action_op_set_val()
1192 		return -EINVAL;  in preaction_op_set_val()
1220 		return -EINVAL;  in preop_op_set_val()
1325 MODULE_DESCRIPTION("watchdog timer based upon the IPMI interface.");