1
2
3
4
5
6
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 if (time_travel_mode != TT_MODE_OFF)
43 time_travel_set_time(time_travel_timer_expiry);
44
45 local_irq_save(flags);
46 do_IRQ(TIMER_IRQ, regs);
47 local_irq_restore(flags);
48}
49
50static int itimer_shutdown(struct clock_event_device *evt)
51{
52 if (time_travel_mode != TT_MODE_OFF)
53 time_travel_set_timer_mode(TT_TMR_DISABLED);
54
55 if (time_travel_mode != TT_MODE_INFCPU)
56 os_timer_disable();
57
58 return 0;
59}
60
61static int itimer_set_periodic(struct clock_event_device *evt)
62{
63 unsigned long long interval = NSEC_PER_SEC / HZ;
64
65 if (time_travel_mode != TT_MODE_OFF) {
66 time_travel_set_timer_mode(TT_TMR_PERIODIC);
67 time_travel_set_timer_expiry(time_travel_time + interval);
68 }
69
70 if (time_travel_mode != TT_MODE_INFCPU)
71 os_timer_set_interval(interval);
72
73 return 0;
74}
75
76static int itimer_next_event(unsigned long delta,
77 struct clock_event_device *evt)
78{
79 delta += 1;
80
81 if (time_travel_mode != TT_MODE_OFF) {
82 time_travel_set_timer_mode(TT_TMR_ONESHOT);
83 time_travel_set_timer_expiry(time_travel_time + delta);
84 }
85
86 if (time_travel_mode != TT_MODE_INFCPU)
87 return os_timer_one_shot(delta);
88
89 return 0;
90}
91
92static int itimer_one_shot(struct clock_event_device *evt)
93{
94 return itimer_next_event(0, evt);
95}
96
97static struct clock_event_device timer_clockevent = {
98 .name = "posix-timer",
99 .rating = 250,
100 .cpumask = cpu_possible_mask,
101 .features = CLOCK_EVT_FEAT_PERIODIC |
102 CLOCK_EVT_FEAT_ONESHOT,
103 .set_state_shutdown = itimer_shutdown,
104 .set_state_periodic = itimer_set_periodic,
105 .set_state_oneshot = itimer_one_shot,
106 .set_next_event = itimer_next_event,
107 .shift = 0,
108 .max_delta_ns = 0xffffffff,
109 .max_delta_ticks = 0xffffffff,
110 .min_delta_ns = TIMER_MIN_DELTA,
111 .min_delta_ticks = TIMER_MIN_DELTA,
112 .irq = 0,
113 .mult = 1,
114};
115
116static irqreturn_t um_timer(int irq, void *dev)
117{
118 if (get_current()->mm != NULL)
119 {
120
121 os_alarm_process(get_current()->mm->context.id.u.pid);
122 }
123
124 (*timer_clockevent.event_handler)(&timer_clockevent);
125
126 return IRQ_HANDLED;
127}
128
129static u64 timer_read(struct clocksource *cs)
130{
131 if (time_travel_mode != TT_MODE_OFF) {
132
133
134
135
136
137
138 time_travel_set_time(time_travel_time + TIMER_MULTIPLIER);
139 return time_travel_time / TIMER_MULTIPLIER;
140 }
141
142 return os_nsecs() / TIMER_MULTIPLIER;
143}
144
145static struct clocksource timer_clocksource = {
146 .name = "timer",
147 .rating = 300,
148 .read = timer_read,
149 .mask = CLOCKSOURCE_MASK(64),
150 .flags = CLOCK_SOURCE_IS_CONTINUOUS,
151};
152
153static void __init um_timer_setup(void)
154{
155 int err;
156
157 err = request_irq(TIMER_IRQ, um_timer, IRQF_TIMER, "hr timer", NULL);
158 if (err != 0)
159 printk(KERN_ERR "register_timer : request_irq failed - "
160 "errno = %d\n", -err);
161
162 err = os_timer_create();
163 if (err != 0) {
164 printk(KERN_ERR "creation of timer failed - errno = %d\n", -err);
165 return;
166 }
167
168 err = clocksource_register_hz(&timer_clocksource, NSEC_PER_SEC/TIMER_MULTIPLIER);
169 if (err) {
170 printk(KERN_ERR "clocksource_register_hz returned %d\n", err);
171 return;
172 }
173 clockevents_register_device(&timer_clockevent);
174}
175
176void read_persistent_clock64(struct timespec64 *ts)
177{
178 long long nsecs;
179
180 if (time_travel_start_set)
181 nsecs = time_travel_start + time_travel_time;
182 else
183 nsecs = os_persistent_clock_emulation();
184
185 set_normalized_timespec64(ts, nsecs / NSEC_PER_SEC,
186 nsecs % NSEC_PER_SEC);
187}
188
189void __init time_init(void)
190{
191 timer_set_signal_handler();
192 late_time_init = um_timer_setup;
193}
194
195#ifdef CONFIG_UML_TIME_TRAVEL_SUPPORT
196unsigned long calibrate_delay_is_known(void)
197{
198 if (time_travel_mode == TT_MODE_INFCPU)
199 return 1;
200 return 0;
201}
202
203int setup_time_travel(char *str)
204{
205 if (strcmp(str, "=inf-cpu") == 0) {
206 time_travel_mode = TT_MODE_INFCPU;
207 timer_clockevent.name = "time-travel-timer-infcpu";
208 timer_clocksource.name = "time-travel-clock";
209 return 1;
210 }
211
212 if (!*str) {
213 time_travel_mode = TT_MODE_BASIC;
214 timer_clockevent.name = "time-travel-timer";
215 timer_clocksource.name = "time-travel-clock";
216 return 1;
217 }
218
219 return -EINVAL;
220}
221
222__setup("time-travel", setup_time_travel);
223__uml_help(setup_time_travel,
224"time-travel\n"
225"This option just enables basic time travel mode, in which the clock/timers\n"
226"inside the UML instance skip forward when there's nothing to do, rather than\n"
227"waiting for real time to elapse. However, instance CPU speed is limited by\n"
228"the real CPU speed, so e.g. a 10ms timer will always fire after ~10ms wall\n"
229"clock (but quicker when there's nothing to do).\n"
230"\n"
231"time-travel=inf-cpu\n"
232"This enables time travel mode with infinite processing power, in which there\n"
233"are no wall clock timers, and any CPU processing happens - as seen from the\n"
234"guest - instantly. This can be useful for accurate simulation regardless of\n"
235"debug overhead, physical CPU speed, etc. but is somewhat dangerous as it can\n"
236"easily lead to getting stuck (e.g. if anything in the system busy loops).\n");
237
238int setup_time_travel_start(char *str)
239{
240 int err;
241
242 err = kstrtoull(str, 0, &time_travel_start);
243 if (err)
244 return err;
245
246 time_travel_start_set = 1;
247 return 1;
248}
249
250__setup("time-travel-start", setup_time_travel_start);
251__uml_help(setup_time_travel_start,
252"time-travel-start=<seconds>\n"
253"Configure the UML instance's wall clock to start at this value rather than\n"
254"the host's wall clock at the time of UML boot.\n");
255#endif
256
