1 // SPDX-License-Identifier: GPL-2.0
3  * Copyright (C) 2015 Anton Ivanov (aivanov@{brocade.com,kot-begemot.co.uk})
5  * Copyright (C) 2012-2014 Cisco Systems
6  * Copyright (C) 2000 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
23 #include <linux/time-internal.h>
42 static int time_travel_ext_fd = -1;
56 	return (unsigned long long)(jiffies - INITIAL_JIFFIES +  in sched_clock()
64 		panic("time-travel: time goes backwards %lld -> %lld\n",  in time_travel_set_time()
85 	printk(KERN_INFO "time-travel: received broadcast 0x%llx\n", bc_message);  in _time_travel_print_bc_msg()
97 	len = time_travel_shm->len;  in time_travel_setup_shm()
99 	if (time_travel_shm->version != UM_TIMETRAVEL_SCHEDSHM_VERSION ||  in time_travel_setup_shm()
112 	time_travel_shm_offset = time_travel_shm->current_time;  in time_travel_setup_shm()
113 	time_travel_shm_client = &time_travel_shm->clients[id];  in time_travel_setup_shm()
114 	time_travel_shm_client->capa |= UM_TIMETRAVEL_SCHEDSHM_CAP_TIME_SHARE;  in time_travel_setup_shm()
116 	/* always look at that free_until from now on */  in time_travel_setup_shm()
117 	time_travel_ext_free_until = &time_travel_shm->free_until;  in time_travel_setup_shm()
149 					      msg->time & UM_TIMETRAVEL_START_ACK_ID);  in time_travel_handle_message()
150 			/* we don't use the logging for now */  in time_travel_handle_message()
158 		panic("time-travel external link is broken\n");  in time_travel_handle_message()
160 		panic("invalid time-travel message - %d bytes\n", ret);  in time_travel_handle_message()
162 	switch (msg->op) {  in time_travel_handle_message()
164 		WARN_ONCE(1, "time-travel: unexpected message %lld\n",  in time_travel_handle_message()
165 			  (unsigned long long)msg->op);  in time_travel_handle_message()
170 		time_travel_set_time(msg->time);  in time_travel_handle_message()
173 			time_travel_shm_client->flags &=  in time_travel_handle_message()
175 			/* no ack for shared memory RUN */  in time_travel_handle_message()
184 		_time_travel_ext_free_until = msg->time;  in time_travel_handle_message()
187 		bc_message = msg->time;  in time_travel_handle_message()
192 	resp.seq = msg->seq;  in time_travel_handle_message()
208 	 * only restore their use when we got the ACK - otherwise we may  in time_travel_ext_req()
209 	 * (will) get interrupted by that, try to queue the IRQ for future  in time_travel_ext_req()
211 	 * for an ACK, but the peer doesn't know we got interrupted and will  in time_travel_ext_req()
216 	 * current time (for UM_TIMETRAVEL_GET) and getting another  in time_travel_ext_req()
217 	 * ACK without a time would confuse us a lot!  in time_travel_ext_req()
225 	/* no ACK expected for WAIT in shared memory mode */  in time_travel_ext_req()
236 		panic("time-travel: ACK message has different seqno! op=%d, seq=%d != %d time=%lld\n",  in time_travel_ext_req()
269 	/* asked for exactly this time previously */  in time_travel_ext_update_request()
278 	 * Note for shm we ignore FREE_UNTIL messages and leave the pointer  in time_travel_ext_update_request()
279 	 * to shared memory, and for non-shm the offset is 0.  in time_travel_ext_update_request()
282 	    time < (*time_travel_ext_free_until - time_travel_shm_offset))  in time_travel_ext_update_request()
291 		running = &time_travel_shm->clients[time_travel_shm->running_id];  in time_travel_ext_update_request()
293 		if (running->capa & UM_TIMETRAVEL_SCHEDSHM_CAP_TIME_SHARE) {  in time_travel_ext_update_request()
294 			time_travel_shm_client->flags |=  in time_travel_ext_update_request()
297 			time_travel_shm_client->req_time = time;  in time_travel_ext_update_request()
298 			if (time < time_travel_shm->free_until)  in time_travel_ext_update_request()
299 				time_travel_shm->free_until = time;  in time_travel_ext_update_request()
312 		if (time_travel_shm->running_id != time_travel_shm_id)  in __time_travel_propagate_time()
313 			panic("time-travel: setting time while not running\n");  in __time_travel_propagate_time()
314 		time_travel_shm->current_time = time_travel_time +  in __time_travel_propagate_time()
327 /* returns true if we must do a wait to the simtime device */
332 	 * don't have to request/wait for anything until then, unless  in time_travel_ext_request()
335 	 * Note for shm we ignore FREE_UNTIL messages and leave the pointer  in time_travel_ext_request()
336 	 * to shared memory, and for non-shm the offset is 0.  in time_travel_ext_request()
339 	    time < (*time_travel_ext_free_until - time_travel_shm_offset))  in time_travel_ext_request()
357 	time_travel_ext_req(UM_TIMETRAVEL_WAIT, -1);  in time_travel_ext_wait()
369 	time_travel_ext_waiting--;  in time_travel_ext_wait()
371 	/* we might request more stuff while polling - reset when we run */  in time_travel_ext_wait()
378 		time_travel_set_time(time_travel_shm->current_time -  in time_travel_ext_get_time()
381 		time_travel_ext_req(UM_TIMETRAVEL_GET, -1);  in time_travel_ext_get_time()
406 	if (e->pending)  in __time_travel_add_event()
409 	e->pending = true;  in __time_travel_add_event()
410 	e->time = time;  in __time_travel_add_event()
421 		if ((tmp->time > e->time) ||  in __time_travel_add_event()
422 		    (tmp->time == e->time && tmp->onstack && e->onstack)) {  in __time_travel_add_event()
423 			list_add_tail(&e->list, &tmp->list);  in __time_travel_add_event()
430 		list_add_tail(&e->list, &time_travel_events);  in __time_travel_add_event()
433 	time_travel_ext_update_request(tmp->time);  in __time_travel_add_event()
434 	time_travel_next_event = tmp->time;  in __time_travel_add_event()
441 	if (WARN_ON(!e->fn))  in time_travel_add_event()
460 		tt_extra_sched_jiffies -= 1;  in time_travel_periodic_timer()
471 	 * Don't do anything for most cases. Note that because here we have  in deliver_time_travel_irqs()
472 	 * to disable IRQs (and re-enable later) we'll actually recurse at  in deliver_time_travel_irqs()
483 		list_del(&e->list);  in deliver_time_travel_irqs()
484 		e->pending = false;  in deliver_time_travel_irqs()
485 		e->fn(e);  in deliver_time_travel_irqs()
498 		e->fn(e);  in time_travel_deliver_event()
500 		list_add_tail(&e->list, &time_travel_irqs);  in time_travel_deliver_event()
506 		e->pending = true;  in time_travel_deliver_event()
512 		e->fn(e);  in time_travel_deliver_event()
522 	if (!e->pending)  in time_travel_del_event()
525 	list_del(&e->list);  in time_travel_del_event()
526 	e->pending = false;  in time_travel_del_event()
539 	/* add it without a handler - we deal with that specifically below */  in time_travel_update_time()
546 		__time_travel_update_time(e->time, idle);  in time_travel_update_time()
551 			BUG_ON(time_travel_time != e->time);  in time_travel_update_time()
556 				if (e->onstack)  in time_travel_update_time()
557 					panic("On-stack event dequeued outside of the stack! time=%lld, event time=%lld, event=%pS\n",  in time_travel_update_time()
558 					      time_travel_time, e->time, e);  in time_travel_update_time()
565 			time_travel_ext_update_request(e->time);  in time_travel_update_time()
603 	 * We could model interrupt latency here, for now just  in time_travel_add_irq_event()
615 		tt_extra_sched_jiffies -= 1;  in time_travel_oneshot_timer()
623 	 * Wait "forever" (using S64_MAX because there are some potential  in time_travel_sleep()
638 			 * This is somewhat wrong - we should get the first  in time_travel_sleep()
643 			os_timer_one_shot(time_travel_timer_event.time - next);  in time_travel_sleep()
668 	unsigned long long id = (unsigned long long)-1;  in time_travel_connect_external()
673 		if (sep - socket > sizeof(buf) - 1)  in time_travel_connect_external()
676 		memcpy(buf, socket, sep - socket);  in time_travel_connect_external()
679 			panic("time-travel: invalid external ID in string '%s'\n",  in time_travel_connect_external()
681 			return -EINVAL;  in time_travel_connect_external()
689 		panic("time-travel: failed to connect to external socket %s\n",  in time_travel_connect_external()
708 		time_travel_start = time_travel_ext_req(UM_TIMETRAVEL_GET_TOD, -1);  in time_travel_set_start()
711 		time_travel_start -= time_travel_time;  in time_travel_set_start()
756 /* externally not usable - redefine here so we can */
766 	 * In basic time-travel mode we still get real interrupts  in timer_handler()
770 	 * This is not the case in inf-cpu mode, since there we  in timer_handler()
839 	.name			= "posix-timer",
852 ….min_delta_ticks	= TIMER_MIN_DELTA, // microsecond resolution should be enough for anyone, same as…
859 	if (get_current()->mm != NULL)  in um_timer()
861         /* userspace - relay signal, results in correct userspace timers */  in um_timer()
862 		os_alarm_process(get_current()->mm->context.id.pid);  in um_timer()
881 		 * even more waiting, and that's not good - it messes up the  in timer_read()
908 		printk(KERN_ERR "register_timer : request_irq failed - "  in um_timer_setup()
909 		       "errno = %d\n", -err);  in um_timer_setup()
913 		printk(KERN_ERR "creation of timer failed - errno = %d\n", -err);  in um_timer_setup()
957 	if (strcmp(str, "=inf-cpu") == 0) {  in setup_time_travel()
959 		timer_clockevent.name = "time-travel-timer-infcpu";  in setup_time_travel()
960 		timer_clocksource.name = "time-travel-clock";  in setup_time_travel()
966 		timer_clockevent.name = "time-travel-timer-external";  in setup_time_travel()
967 		timer_clocksource.name = "time-travel-clock-external";  in setup_time_travel()
973 		timer_clockevent.name = "time-travel-timer";  in setup_time_travel()
974 		timer_clocksource.name = "time-travel-clock";  in setup_time_travel()
978 	return -EINVAL;  in setup_time_travel()
981 __setup("time-travel", setup_time_travel);
983 "time-travel\n"
986 "waiting for real time to elapse. However, instance CPU speed is limited by\n"
987 "the real CPU speed, so e.g. a 10ms timer will always fire after ~10ms wall\n"
990 "time-travel=inf-cpu\n"
992 "are no wall clock timers, and any CPU processing happens - as seen from the\n"
993 "guest - instantly. This can be useful for accurate simulation regardless of\n"
997 "time-travel=ext:[ID:]/path/to/socket\n"
998 "This enables time travel mode similar to =inf-cpu, except the system will\n"
1003 "The optional ID is a 64-bit integer that's sent to the central scheduler.\n");
1017 __setup("time-travel-start=", setup_time_travel_start);
1019 "time-travel-start=<nanoseconds>\n"
1045 static struct kobj_attribute bc_attribute = __ATTR(bc-message, 0660, bc_show, bc_store);
1052 	bc_time_kobject = kobject_create_and_add("um-ext-time", kernel_kobj);  in um_bc_start()