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1/*
2 * Copyright (C) 2000 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
3 * Licensed under the GPL
4 */
5
6#include <linux/clockchips.h>
7#include <linux/init.h>
8#include <linux/interrupt.h>
9#include <linux/jiffies.h>
10#include <linux/threads.h>
11#include <asm/irq.h>
12#include <asm/param.h>
13#include "kern_util.h"
14#include "os.h"
15
16void timer_handler(int sig, struct uml_pt_regs *regs)
17{
18 unsigned long flags;
19
20 local_irq_save(flags);
21 do_IRQ(TIMER_IRQ, regs);
22 local_irq_restore(flags);
23}
24
25static void itimer_set_mode(enum clock_event_mode mode,
26 struct clock_event_device *evt)
27{
28 switch (mode) {
29 case CLOCK_EVT_MODE_PERIODIC:
30 set_interval();
31 break;
32
33 case CLOCK_EVT_MODE_SHUTDOWN:
34 case CLOCK_EVT_MODE_UNUSED:
35 case CLOCK_EVT_MODE_ONESHOT:
36 disable_timer();
37 break;
38
39 case CLOCK_EVT_MODE_RESUME:
40 break;
41 }
42}
43
44static int itimer_next_event(unsigned long delta,
45 struct clock_event_device *evt)
46{
47 return timer_one_shot(delta + 1);
48}
49
50static struct clock_event_device itimer_clockevent = {
51 .name = "itimer",
52 .rating = 250,
53 .cpumask = cpu_all_mask,
54 .features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT,
55 .set_mode = itimer_set_mode,
56 .set_next_event = itimer_next_event,
57 .shift = 32,
58 .irq = 0,
59};
60
61static irqreturn_t um_timer(int irq, void *dev)
62{
63 (*itimer_clockevent.event_handler)(&itimer_clockevent);
64
65 return IRQ_HANDLED;
66}
67
68static cycle_t itimer_read(struct clocksource *cs)
69{
70 return os_nsecs() / 1000;
71}
72
73static struct clocksource itimer_clocksource = {
74 .name = "itimer",
75 .rating = 300,
76 .read = itimer_read,
77 .mask = CLOCKSOURCE_MASK(64),
78 .flags = CLOCK_SOURCE_IS_CONTINUOUS,
79};
80
81static void __init setup_itimer(void)
82{
83 int err;
84
85 err = request_irq(TIMER_IRQ, um_timer, 0, "timer", NULL);
86 if (err != 0)
87 printk(KERN_ERR "register_timer : request_irq failed - "
88 "errno = %d\n", -err);
89
90 itimer_clockevent.mult = div_sc(HZ, NSEC_PER_SEC, 32);
91 itimer_clockevent.max_delta_ns =
92 clockevent_delta2ns(60 * HZ, &itimer_clockevent);
93 itimer_clockevent.min_delta_ns =
94 clockevent_delta2ns(1, &itimer_clockevent);
95 err = clocksource_register_hz(&itimer_clocksource, USEC_PER_SEC);
96 if (err) {
97 printk(KERN_ERR "clocksource_register_hz returned %d\n", err);
98 return;
99 }
100 clockevents_register_device(&itimer_clockevent);
101}
102
103void read_persistent_clock(struct timespec *ts)
104{
105 long long nsecs = os_nsecs();
106
107 set_normalized_timespec(ts, nsecs / NSEC_PER_SEC,
108 nsecs % NSEC_PER_SEC);
109}
110
111void __init time_init(void)
112{
113 timer_init();
114 late_time_init = setup_itimer;
115}
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