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_mode(TT_TMR_DISABLED); 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_mode(TT_TMR_PERIODIC); 67 time_travel_set_timer_expiry(time_travel_time + interval); 68 time_travel_set_timer_interval(interval); 69 } 70 71 if (time_travel_mode != TT_MODE_INFCPU) 72 os_timer_set_interval(interval); 73 74 return 0; 75 } 76 77 static int itimer_next_event(unsigned long delta, 78 struct clock_event_device *evt) 79 { 80 delta += 1; 81 82 if (time_travel_mode != TT_MODE_OFF) { 83 time_travel_set_timer_mode(TT_TMR_ONESHOT); 84 time_travel_set_timer_expiry(time_travel_time + delta); 85 } 86 87 if (time_travel_mode != TT_MODE_INFCPU) 88 return os_timer_one_shot(delta); 89 90 return 0; 91 } 92 93 static int itimer_one_shot(struct clock_event_device *evt) 94 { 95 return itimer_next_event(0, evt); 96 } 97 98 static struct clock_event_device timer_clockevent = { 99 .name = "posix-timer", 100 .rating = 250, 101 .cpumask = cpu_possible_mask, 102 .features = CLOCK_EVT_FEAT_PERIODIC | 103 CLOCK_EVT_FEAT_ONESHOT, 104 .set_state_shutdown = itimer_shutdown, 105 .set_state_periodic = itimer_set_periodic, 106 .set_state_oneshot = itimer_one_shot, 107 .set_next_event = itimer_next_event, 108 .shift = 0, 109 .max_delta_ns = 0xffffffff, 110 .max_delta_ticks = 0xffffffff, 111 .min_delta_ns = TIMER_MIN_DELTA, 112 .min_delta_ticks = TIMER_MIN_DELTA, // microsecond resolution should be enough for anyone, same as 640K RAM 113 .irq = 0, 114 .mult = 1, 115 }; 116 117 static irqreturn_t um_timer(int irq, void *dev) 118 { 119 if (get_current()->mm != NULL) 120 { 121 /* userspace - relay signal, results in correct userspace timers */ 122 os_alarm_process(get_current()->mm->context.id.u.pid); 123 } 124 125 (*timer_clockevent.event_handler)(&timer_clockevent); 126 127 return IRQ_HANDLED; 128 } 129 130 static u64 timer_read(struct clocksource *cs) 131 { 132 if (time_travel_mode != TT_MODE_OFF) { 133 /* 134 * We make reading the timer cost a bit so that we don't get 135 * stuck in loops that expect time to move more than the 136 * exact requested sleep amount, e.g. python's socket server, 137 * see https://bugs.python.org/issue37026. 138 */ 139 time_travel_set_time(time_travel_time + TIMER_MULTIPLIER); 140 return time_travel_time / TIMER_MULTIPLIER; 141 } 142 143 return os_nsecs() / TIMER_MULTIPLIER; 144 } 145 146 static struct clocksource timer_clocksource = { 147 .name = "timer", 148 .rating = 300, 149 .read = timer_read, 150 .mask = CLOCKSOURCE_MASK(64), 151 .flags = CLOCK_SOURCE_IS_CONTINUOUS, 152 }; 153 154 static void __init um_timer_setup(void) 155 { 156 int err; 157 158 err = request_irq(TIMER_IRQ, um_timer, IRQF_TIMER, "hr timer", NULL); 159 if (err != 0) 160 printk(KERN_ERR "register_timer : request_irq failed - " 161 "errno = %d\n", -err); 162 163 err = os_timer_create(); 164 if (err != 0) { 165 printk(KERN_ERR "creation of timer failed - errno = %d\n", -err); 166 return; 167 } 168 169 err = clocksource_register_hz(&timer_clocksource, NSEC_PER_SEC/TIMER_MULTIPLIER); 170 if (err) { 171 printk(KERN_ERR "clocksource_register_hz returned %d\n", err); 172 return; 173 } 174 clockevents_register_device(&timer_clockevent); 175 } 176 177 void read_persistent_clock64(struct timespec64 *ts) 178 { 179 long long nsecs; 180 181 if (time_travel_start_set) 182 nsecs = time_travel_start + time_travel_time; 183 else 184 nsecs = os_persistent_clock_emulation(); 185 186 set_normalized_timespec64(ts, nsecs / NSEC_PER_SEC, 187 nsecs % NSEC_PER_SEC); 188 } 189 190 void __init time_init(void) 191 { 192 timer_set_signal_handler(); 193 late_time_init = um_timer_setup; 194 } 195 196 #ifdef CONFIG_UML_TIME_TRAVEL_SUPPORT 197 unsigned long calibrate_delay_is_known(void) 198 { 199 if (time_travel_mode == TT_MODE_INFCPU) 200 return 1; 201 return 0; 202 } 203 204 int setup_time_travel(char *str) 205 { 206 if (strcmp(str, "=inf-cpu") == 0) { 207 time_travel_mode = TT_MODE_INFCPU; 208 timer_clockevent.name = "time-travel-timer-infcpu"; 209 timer_clocksource.name = "time-travel-clock"; 210 return 1; 211 } 212 213 if (!*str) { 214 time_travel_mode = TT_MODE_BASIC; 215 timer_clockevent.name = "time-travel-timer"; 216 timer_clocksource.name = "time-travel-clock"; 217 return 1; 218 } 219 220 return -EINVAL; 221 } 222 223 __setup("time-travel", setup_time_travel); 224 __uml_help(setup_time_travel, 225 "time-travel\n" 226 "This option just enables basic time travel mode, in which the clock/timers\n" 227 "inside the UML instance skip forward when there's nothing to do, rather than\n" 228 "waiting for real time to elapse. However, instance CPU speed is limited by\n" 229 "the real CPU speed, so e.g. a 10ms timer will always fire after ~10ms wall\n" 230 "clock (but quicker when there's nothing to do).\n" 231 "\n" 232 "time-travel=inf-cpu\n" 233 "This enables time travel mode with infinite processing power, in which there\n" 234 "are no wall clock timers, and any CPU processing happens - as seen from the\n" 235 "guest - instantly. This can be useful for accurate simulation regardless of\n" 236 "debug overhead, physical CPU speed, etc. but is somewhat dangerous as it can\n" 237 "easily lead to getting stuck (e.g. if anything in the system busy loops).\n"); 238 239 int setup_time_travel_start(char *str) 240 { 241 int err; 242 243 err = kstrtoull(str, 0, &time_travel_start); 244 if (err) 245 return err; 246 247 time_travel_start_set = 1; 248 return 1; 249 } 250 251 __setup("time-travel-start", setup_time_travel_start); 252 __uml_help(setup_time_travel_start, 253 "time-travel-start=<seconds>\n" 254 "Configure the UML instance's wall clock to start at this value rather than\n" 255 "the host's wall clock at the time of UML boot.\n"); 256 #endif 257