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 #include <shared/init.h> 23 24 #ifdef CONFIG_UML_TIME_TRAVEL_SUPPORT 25 enum time_travel_mode time_travel_mode; 26 unsigned long long time_travel_time; 27 enum time_travel_timer_mode time_travel_timer_mode; 28 unsigned long long time_travel_timer_expiry; 29 unsigned long long time_travel_timer_interval; 30 31 static bool time_travel_start_set; 32 static unsigned long long time_travel_start; 33 #else 34 #define time_travel_start_set 0 35 #define time_travel_start 0 36 #endif 37 38 void 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 50 static int itimer_shutdown(struct clock_event_device *evt) 51 { 52 if (time_travel_mode != TT_MODE_OFF) 53 time_travel_set_timer(TT_TMR_DISABLED, 0); 54 55 if (time_travel_mode != TT_MODE_INFCPU) 56 os_timer_disable(); 57 58 return 0; 59 } 60 61 static 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(TT_TMR_PERIODIC, 67 time_travel_time + interval); 68 69 if (time_travel_mode != TT_MODE_INFCPU) 70 os_timer_set_interval(interval); 71 72 return 0; 73 } 74 75 static int itimer_next_event(unsigned long delta, 76 struct clock_event_device *evt) 77 { 78 delta += 1; 79 80 if (time_travel_mode != TT_MODE_OFF) 81 time_travel_set_timer(TT_TMR_ONESHOT, 82 time_travel_time + delta); 83 84 if (time_travel_mode != TT_MODE_INFCPU) 85 return os_timer_one_shot(delta); 86 87 return 0; 88 } 89 90 static int itimer_one_shot(struct clock_event_device *evt) 91 { 92 return itimer_next_event(0, evt); 93 } 94 95 static struct clock_event_device timer_clockevent = { 96 .name = "posix-timer", 97 .rating = 250, 98 .cpumask = cpu_possible_mask, 99 .features = CLOCK_EVT_FEAT_PERIODIC | 100 CLOCK_EVT_FEAT_ONESHOT, 101 .set_state_shutdown = itimer_shutdown, 102 .set_state_periodic = itimer_set_periodic, 103 .set_state_oneshot = itimer_one_shot, 104 .set_next_event = itimer_next_event, 105 .shift = 0, 106 .max_delta_ns = 0xffffffff, 107 .max_delta_ticks = 0xffffffff, 108 .min_delta_ns = TIMER_MIN_DELTA, 109 .min_delta_ticks = TIMER_MIN_DELTA, // microsecond resolution should be enough for anyone, same as 640K RAM 110 .irq = 0, 111 .mult = 1, 112 }; 113 114 static irqreturn_t um_timer(int irq, void *dev) 115 { 116 if (get_current()->mm != NULL) 117 { 118 /* userspace - relay signal, results in correct userspace timers */ 119 os_alarm_process(get_current()->mm->context.id.u.pid); 120 } 121 122 (*timer_clockevent.event_handler)(&timer_clockevent); 123 124 return IRQ_HANDLED; 125 } 126 127 static u64 timer_read(struct clocksource *cs) 128 { 129 if (time_travel_mode != TT_MODE_OFF) { 130 /* 131 * We make reading the timer cost a bit so that we don't get 132 * stuck in loops that expect time to move more than the 133 * exact requested sleep amount, e.g. python's socket server, 134 * see https://bugs.python.org/issue37026. 135 */ 136 time_travel_set_time(time_travel_time + TIMER_MULTIPLIER); 137 return time_travel_time / TIMER_MULTIPLIER; 138 } 139 140 return os_nsecs() / TIMER_MULTIPLIER; 141 } 142 143 static struct clocksource timer_clocksource = { 144 .name = "timer", 145 .rating = 300, 146 .read = timer_read, 147 .mask = CLOCKSOURCE_MASK(64), 148 .flags = CLOCK_SOURCE_IS_CONTINUOUS, 149 }; 150 151 static void __init um_timer_setup(void) 152 { 153 int err; 154 155 err = request_irq(TIMER_IRQ, um_timer, IRQF_TIMER, "hr timer", NULL); 156 if (err != 0) 157 printk(KERN_ERR "register_timer : request_irq failed - " 158 "errno = %d\n", -err); 159 160 err = os_timer_create(); 161 if (err != 0) { 162 printk(KERN_ERR "creation of timer failed - errno = %d\n", -err); 163 return; 164 } 165 166 err = clocksource_register_hz(&timer_clocksource, NSEC_PER_SEC/TIMER_MULTIPLIER); 167 if (err) { 168 printk(KERN_ERR "clocksource_register_hz returned %d\n", err); 169 return; 170 } 171 clockevents_register_device(&timer_clockevent); 172 } 173 174 void read_persistent_clock64(struct timespec64 *ts) 175 { 176 long long nsecs; 177 178 if (time_travel_start_set) 179 nsecs = time_travel_start + time_travel_time; 180 else 181 nsecs = os_persistent_clock_emulation(); 182 183 set_normalized_timespec64(ts, nsecs / NSEC_PER_SEC, 184 nsecs % NSEC_PER_SEC); 185 } 186 187 void __init time_init(void) 188 { 189 timer_set_signal_handler(); 190 late_time_init = um_timer_setup; 191 } 192 193 #ifdef CONFIG_UML_TIME_TRAVEL_SUPPORT 194 unsigned long calibrate_delay_is_known(void) 195 { 196 if (time_travel_mode == TT_MODE_INFCPU) 197 return 1; 198 return 0; 199 } 200 201 int setup_time_travel(char *str) 202 { 203 if (strcmp(str, "=inf-cpu") == 0) { 204 time_travel_mode = TT_MODE_INFCPU; 205 timer_clockevent.name = "time-travel-timer-infcpu"; 206 timer_clocksource.name = "time-travel-clock"; 207 return 1; 208 } 209 210 if (!*str) { 211 time_travel_mode = TT_MODE_BASIC; 212 timer_clockevent.name = "time-travel-timer"; 213 timer_clocksource.name = "time-travel-clock"; 214 return 1; 215 } 216 217 return -EINVAL; 218 } 219 220 __setup("time-travel", setup_time_travel); 221 __uml_help(setup_time_travel, 222 "time-travel\n" 223 "This option just enables basic time travel mode, in which the clock/timers\n" 224 "inside the UML instance skip forward when there's nothing to do, rather than\n" 225 "waiting for real time to elapse. However, instance CPU speed is limited by\n" 226 "the real CPU speed, so e.g. a 10ms timer will always fire after ~10ms wall\n" 227 "clock (but quicker when there's nothing to do).\n" 228 "\n" 229 "time-travel=inf-cpu\n" 230 "This enables time travel mode with infinite processing power, in which there\n" 231 "are no wall clock timers, and any CPU processing happens - as seen from the\n" 232 "guest - instantly. This can be useful for accurate simulation regardless of\n" 233 "debug overhead, physical CPU speed, etc. but is somewhat dangerous as it can\n" 234 "easily lead to getting stuck (e.g. if anything in the system busy loops).\n"); 235 236 int setup_time_travel_start(char *str) 237 { 238 int err; 239 240 err = kstrtoull(str, 0, &time_travel_start); 241 if (err) 242 return err; 243 244 time_travel_start_set = 1; 245 return 1; 246 } 247 248 __setup("time-travel-start", setup_time_travel_start); 249 __uml_help(setup_time_travel_start, 250 "time-travel-start=<seconds>\n" 251 "Configure the UML instance's wall clock to start at this value rather than\n" 252 "the host's wall clock at the time of UML boot.\n"); 253 #endif 254