1/*
  2 * Copyright (C) 2015 Anton Ivanov (aivanov@{brocade.com,kot-begemot.co.uk})
  3 * Copyright (C) 2015 Thomas Meyer (thomas@m3y3r.de)
  4 * Copyright (C) 2012-2014 Cisco Systems
  5 * Copyright (C) 2000 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
  6 * Licensed under the GPL
  7 */
  8
  9#include <linux/clockchips.h>
 10#include <linux/init.h>
 11#include <linux/interrupt.h>
 12#include <linux/jiffies.h>
 13#include <linux/mm.h>
 14#include <linux/sched.h>
 15#include <linux/spinlock.h>
 16#include <linux/threads.h>
 17#include <asm/irq.h>
 18#include <asm/param.h>
 19#include <kern_util.h>
 20#include <os.h>
 21#include <timer-internal.h>
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 22
 23void timer_handler(int sig, struct siginfo *unused_si, struct uml_pt_regs *regs)
 24{
 25	unsigned long flags;
 26
 
 
 
 
 
 
 
 
 
 
 
 27	local_irq_save(flags);
 28	do_IRQ(TIMER_IRQ, regs);
 29	local_irq_restore(flags);
 30}
 31
 32static int itimer_shutdown(struct clock_event_device *evt)
 33{
 34	os_timer_disable();
 
 
 
 
 
 35	return 0;
 36}
 37
 38static int itimer_set_periodic(struct clock_event_device *evt)
 39{
 40	os_timer_set_interval(NULL, NULL);
 
 
 
 
 
 
 
 
 
 
 41	return 0;
 42}
 43
 44static int itimer_next_event(unsigned long delta,
 45			     struct clock_event_device *evt)
 46{
 47	return os_timer_one_shot(delta);
 
 
 
 
 
 
 
 
 
 
 48}
 49
 50static int itimer_one_shot(struct clock_event_device *evt)
 51{
 52	os_timer_one_shot(1);
 53	return 0;
 54}
 55
 56static struct clock_event_device timer_clockevent = {
 57	.name			= "posix-timer",
 58	.rating			= 250,
 59	.cpumask		= cpu_all_mask,
 60	.features		= CLOCK_EVT_FEAT_PERIODIC |
 61				  CLOCK_EVT_FEAT_ONESHOT,
 62	.set_state_shutdown	= itimer_shutdown,
 63	.set_state_periodic	= itimer_set_periodic,
 64	.set_state_oneshot	= itimer_one_shot,
 65	.set_next_event		= itimer_next_event,
 66	.shift			= 0,
 67	.max_delta_ns		= 0xffffffff,
 68	.max_delta_ticks	= 0xffffffff,
 69	.min_delta_ns		= TIMER_MIN_DELTA,
 70	.min_delta_ticks	= TIMER_MIN_DELTA, // microsecond resolution should be enough for anyone, same as 640K RAM
 71	.irq			= 0,
 72	.mult			= 1,
 73};
 74
 75static irqreturn_t um_timer(int irq, void *dev)
 76{
 77	if (get_current()->mm != NULL)
 78	{
 79        /* userspace - relay signal, results in correct userspace timers */
 80		os_alarm_process(get_current()->mm->context.id.u.pid);
 81	}
 82
 83	(*timer_clockevent.event_handler)(&timer_clockevent);
 84
 85	return IRQ_HANDLED;
 86}
 87
 88static u64 timer_read(struct clocksource *cs)
 89{
 
 
 
 
 
 
 
 
 
 
 
 90	return os_nsecs() / TIMER_MULTIPLIER;
 91}
 92
 93static struct clocksource timer_clocksource = {
 94	.name		= "timer",
 95	.rating		= 300,
 96	.read		= timer_read,
 97	.mask		= CLOCKSOURCE_MASK(64),
 98	.flags		= CLOCK_SOURCE_IS_CONTINUOUS,
 99};
100
101static void __init um_timer_setup(void)
102{
103	int err;
104
105	err = request_irq(TIMER_IRQ, um_timer, IRQF_TIMER, "hr timer", NULL);
106	if (err != 0)
107		printk(KERN_ERR "register_timer : request_irq failed - "
108		       "errno = %d\n", -err);
109
110	err = os_timer_create(NULL);
111	if (err != 0) {
112		printk(KERN_ERR "creation of timer failed - errno = %d\n", -err);
113		return;
114	}
115
116	err = clocksource_register_hz(&timer_clocksource, NSEC_PER_SEC/TIMER_MULTIPLIER);
117	if (err) {
118		printk(KERN_ERR "clocksource_register_hz returned %d\n", err);
119		return;
120	}
121	clockevents_register_device(&timer_clockevent);
122}
123
124void read_persistent_clock64(struct timespec64 *ts)
125{
126	long long nsecs = os_persistent_clock_emulation();
 
 
 
 
 
127
128	set_normalized_timespec64(ts, nsecs / NSEC_PER_SEC,
129				  nsecs % NSEC_PER_SEC);
130}
131
132void __init time_init(void)
133{
134	timer_set_signal_handler();
135	late_time_init = um_timer_setup;
136}

  1// SPDX-License-Identifier: GPL-2.0
  2/*
  3 * Copyright (C) 2015 Anton Ivanov (aivanov@{brocade.com,kot-begemot.co.uk})
  4 * Copyright (C) 2015 Thomas Meyer (thomas@m3y3r.de)
  5 * Copyright (C) 2012-2014 Cisco Systems
  6 * Copyright (C) 2000 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
 
  7 */
  8
  9#include <linux/clockchips.h>
 10#include <linux/init.h>
 11#include <linux/interrupt.h>
 12#include <linux/jiffies.h>
 13#include <linux/mm.h>
 14#include <linux/sched.h>
 15#include <linux/spinlock.h>
 16#include <linux/threads.h>
 17#include <asm/irq.h>
 18#include <asm/param.h>
 19#include <kern_util.h>
 20#include <os.h>
 21#include <timer-internal.h>
 22#include <shared/init.h>
 23
 24#ifdef CONFIG_UML_TIME_TRAVEL_SUPPORT
 25enum time_travel_mode time_travel_mode;
 26unsigned long long time_travel_time;
 27enum time_travel_timer_mode time_travel_timer_mode;
 28unsigned long long time_travel_timer_expiry;
 29unsigned long long time_travel_timer_interval;
 30
 31static bool time_travel_start_set;
 32static unsigned long long time_travel_start;
 33#else
 34#define time_travel_start_set 0
 35#define time_travel_start 0
 36#endif
 37
 38void timer_handler(int sig, struct siginfo *unused_si, struct uml_pt_regs *regs)
 39{
 40	unsigned long flags;
 41
 42	/*
 43	 * In basic time-travel mode we still get real interrupts
 44	 * (signals) but since we don't read time from the OS, we
 45	 * must update the simulated time here to the expiry when
 46	 * we get a signal.
 47	 * This is not the case in inf-cpu mode, since there we
 48	 * never get any real signals from the OS.
 49	 */
 50	if (time_travel_mode == TT_MODE_BASIC)
 51		time_travel_set_time(time_travel_timer_expiry);
 52
 53	local_irq_save(flags);
 54	do_IRQ(TIMER_IRQ, regs);
 55	local_irq_restore(flags);
 56}
 57
 58static int itimer_shutdown(struct clock_event_device *evt)
 59{
 60	if (time_travel_mode != TT_MODE_OFF)
 61		time_travel_set_timer_mode(TT_TMR_DISABLED);
 62
 63	if (time_travel_mode != TT_MODE_INFCPU)
 64		os_timer_disable();
 65
 66	return 0;
 67}
 68
 69static int itimer_set_periodic(struct clock_event_device *evt)
 70{
 71	unsigned long long interval = NSEC_PER_SEC / HZ;
 72
 73	if (time_travel_mode != TT_MODE_OFF) {
 74		time_travel_set_timer_mode(TT_TMR_PERIODIC);
 75		time_travel_set_timer_expiry(time_travel_time + interval);
 76		time_travel_set_timer_interval(interval);
 77	}
 78
 79	if (time_travel_mode != TT_MODE_INFCPU)
 80		os_timer_set_interval(interval);
 81
 82	return 0;
 83}
 84
 85static int itimer_next_event(unsigned long delta,
 86			     struct clock_event_device *evt)
 87{
 88	delta += 1;
 89
 90	if (time_travel_mode != TT_MODE_OFF) {
 91		time_travel_set_timer_mode(TT_TMR_ONESHOT);
 92		time_travel_set_timer_expiry(time_travel_time + delta);
 93	}
 94
 95	if (time_travel_mode != TT_MODE_INFCPU)
 96		return os_timer_one_shot(delta);
 97
 98	return 0;
 99}
100
101static int itimer_one_shot(struct clock_event_device *evt)
102{
103	return itimer_next_event(0, evt);
 
104}
105
106static struct clock_event_device timer_clockevent = {
107	.name			= "posix-timer",
108	.rating			= 250,
109	.cpumask		= cpu_possible_mask,
110	.features		= CLOCK_EVT_FEAT_PERIODIC |
111				  CLOCK_EVT_FEAT_ONESHOT,
112	.set_state_shutdown	= itimer_shutdown,
113	.set_state_periodic	= itimer_set_periodic,
114	.set_state_oneshot	= itimer_one_shot,
115	.set_next_event		= itimer_next_event,
116	.shift			= 0,
117	.max_delta_ns		= 0xffffffff,
118	.max_delta_ticks	= 0xffffffff,
119	.min_delta_ns		= TIMER_MIN_DELTA,
120	.min_delta_ticks	= TIMER_MIN_DELTA, // microsecond resolution should be enough for anyone, same as 640K RAM
121	.irq			= 0,
122	.mult			= 1,
123};
124
125static irqreturn_t um_timer(int irq, void *dev)
126{
127	if (get_current()->mm != NULL)
128	{
129        /* userspace - relay signal, results in correct userspace timers */
130		os_alarm_process(get_current()->mm->context.id.u.pid);
131	}
132
133	(*timer_clockevent.event_handler)(&timer_clockevent);
134
135	return IRQ_HANDLED;
136}
137
138static u64 timer_read(struct clocksource *cs)
139{
140	if (time_travel_mode != TT_MODE_OFF) {
141		/*
142		 * We make reading the timer cost a bit so that we don't get
143		 * stuck in loops that expect time to move more than the
144		 * exact requested sleep amount, e.g. python's socket server,
145		 * see https://bugs.python.org/issue37026.
146		 */
147		time_travel_set_time(time_travel_time + TIMER_MULTIPLIER);
148		return time_travel_time / TIMER_MULTIPLIER;
149	}
150
151	return os_nsecs() / TIMER_MULTIPLIER;
152}
153
154static struct clocksource timer_clocksource = {
155	.name		= "timer",
156	.rating		= 300,
157	.read		= timer_read,
158	.mask		= CLOCKSOURCE_MASK(64),
159	.flags		= CLOCK_SOURCE_IS_CONTINUOUS,
160};
161
162static void __init um_timer_setup(void)
163{
164	int err;
165
166	err = request_irq(TIMER_IRQ, um_timer, IRQF_TIMER, "hr timer", NULL);
167	if (err != 0)
168		printk(KERN_ERR "register_timer : request_irq failed - "
169		       "errno = %d\n", -err);
170
171	err = os_timer_create();
172	if (err != 0) {
173		printk(KERN_ERR "creation of timer failed - errno = %d\n", -err);
174		return;
175	}
176
177	err = clocksource_register_hz(&timer_clocksource, NSEC_PER_SEC/TIMER_MULTIPLIER);
178	if (err) {
179		printk(KERN_ERR "clocksource_register_hz returned %d\n", err);
180		return;
181	}
182	clockevents_register_device(&timer_clockevent);
183}
184
185void read_persistent_clock64(struct timespec64 *ts)
186{
187	long long nsecs;
188
189	if (time_travel_start_set)
190		nsecs = time_travel_start + time_travel_time;
191	else
192		nsecs = os_persistent_clock_emulation();
193
194	set_normalized_timespec64(ts, nsecs / NSEC_PER_SEC,
195				  nsecs % NSEC_PER_SEC);
196}
197
198void __init time_init(void)
199{
200	timer_set_signal_handler();
201	late_time_init = um_timer_setup;
202}
203
204#ifdef CONFIG_UML_TIME_TRAVEL_SUPPORT
205unsigned long calibrate_delay_is_known(void)
206{
207	if (time_travel_mode == TT_MODE_INFCPU)
208		return 1;
209	return 0;
210}
211
212int setup_time_travel(char *str)
213{
214	if (strcmp(str, "=inf-cpu") == 0) {
215		time_travel_mode = TT_MODE_INFCPU;
216		timer_clockevent.name = "time-travel-timer-infcpu";
217		timer_clocksource.name = "time-travel-clock";
218		return 1;
219	}
220
221	if (!*str) {
222		time_travel_mode = TT_MODE_BASIC;
223		timer_clockevent.name = "time-travel-timer";
224		timer_clocksource.name = "time-travel-clock";
225		return 1;
226	}
227
228	return -EINVAL;
229}
230
231__setup("time-travel", setup_time_travel);
232__uml_help(setup_time_travel,
233"time-travel\n"
234"This option just enables basic time travel mode, in which the clock/timers\n"
235"inside the UML instance skip forward when there's nothing to do, rather than\n"
236"waiting for real time to elapse. However, instance CPU speed is limited by\n"
237"the real CPU speed, so e.g. a 10ms timer will always fire after ~10ms wall\n"
238"clock (but quicker when there's nothing to do).\n"
239"\n"
240"time-travel=inf-cpu\n"
241"This enables time travel mode with infinite processing power, in which there\n"
242"are no wall clock timers, and any CPU processing happens - as seen from the\n"
243"guest - instantly. This can be useful for accurate simulation regardless of\n"
244"debug overhead, physical CPU speed, etc. but is somewhat dangerous as it can\n"
245"easily lead to getting stuck (e.g. if anything in the system busy loops).\n");
246
247int setup_time_travel_start(char *str)
248{
249	int err;
250
251	err = kstrtoull(str, 0, &time_travel_start);
252	if (err)
253		return err;
254
255	time_travel_start_set = 1;
256	return 1;
257}
258
259__setup("time-travel-start", setup_time_travel_start);
260__uml_help(setup_time_travel_start,
261"time-travel-start=<seconds>\n"
262"Configure the UML instance's wall clock to start at this value rather than\n"
263"the host's wall clock at the time of UML boot.\n");
264#endif