254 lines
6.5 KiB
C
254 lines
6.5 KiB
C
/*
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* Copyright (C) 2015 Anton Ivanov (aivanov@{brocade.com,kot-begemot.co.uk})
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* Copyright (C) 2015 Thomas Meyer (thomas@m3y3r.de)
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* Copyright (C) 2012-2014 Cisco Systems
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* Copyright (C) 2000 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
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* Licensed under the GPL
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*/
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#include <linux/clockchips.h>
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#include <linux/init.h>
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#include <linux/interrupt.h>
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#include <linux/jiffies.h>
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#include <linux/mm.h>
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#include <linux/sched.h>
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#include <linux/spinlock.h>
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#include <linux/threads.h>
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#include <asm/irq.h>
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#include <asm/param.h>
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#include <kern_util.h>
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#include <os.h>
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#include <timer-internal.h>
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#include <shared/init.h>
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#ifdef CONFIG_UML_TIME_TRAVEL_SUPPORT
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enum time_travel_mode time_travel_mode;
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unsigned long long time_travel_time;
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enum time_travel_timer_mode time_travel_timer_mode;
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unsigned long long time_travel_timer_expiry;
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unsigned long long time_travel_timer_interval;
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static bool time_travel_start_set;
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static unsigned long long time_travel_start;
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#else
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#define time_travel_start_set 0
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#define time_travel_start 0
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#endif
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void timer_handler(int sig, struct siginfo *unused_si, struct uml_pt_regs *regs)
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{
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unsigned long flags;
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if (time_travel_mode != TT_MODE_OFF)
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time_travel_set_time(time_travel_timer_expiry);
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local_irq_save(flags);
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do_IRQ(TIMER_IRQ, regs);
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local_irq_restore(flags);
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}
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static int itimer_shutdown(struct clock_event_device *evt)
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{
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if (time_travel_mode != TT_MODE_OFF)
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time_travel_set_timer(TT_TMR_DISABLED, 0);
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if (time_travel_mode != TT_MODE_INFCPU)
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os_timer_disable();
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return 0;
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}
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static int itimer_set_periodic(struct clock_event_device *evt)
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{
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unsigned long long interval = NSEC_PER_SEC / HZ;
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if (time_travel_mode != TT_MODE_OFF)
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time_travel_set_timer(TT_TMR_PERIODIC,
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time_travel_time + interval);
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if (time_travel_mode != TT_MODE_INFCPU)
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os_timer_set_interval(interval);
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return 0;
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}
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static int itimer_next_event(unsigned long delta,
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struct clock_event_device *evt)
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{
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delta += 1;
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if (time_travel_mode != TT_MODE_OFF)
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time_travel_set_timer(TT_TMR_ONESHOT,
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time_travel_time + delta);
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if (time_travel_mode != TT_MODE_INFCPU)
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return os_timer_one_shot(delta);
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return 0;
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}
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static int itimer_one_shot(struct clock_event_device *evt)
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{
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return itimer_next_event(0, evt);
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}
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static struct clock_event_device timer_clockevent = {
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.name = "posix-timer",
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.rating = 250,
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.cpumask = cpu_possible_mask,
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.features = CLOCK_EVT_FEAT_PERIODIC |
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CLOCK_EVT_FEAT_ONESHOT,
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.set_state_shutdown = itimer_shutdown,
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.set_state_periodic = itimer_set_periodic,
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.set_state_oneshot = itimer_one_shot,
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.set_next_event = itimer_next_event,
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.shift = 0,
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.max_delta_ns = 0xffffffff,
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.max_delta_ticks = 0xffffffff,
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.min_delta_ns = TIMER_MIN_DELTA,
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.min_delta_ticks = TIMER_MIN_DELTA, // microsecond resolution should be enough for anyone, same as 640K RAM
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.irq = 0,
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.mult = 1,
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};
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static irqreturn_t um_timer(int irq, void *dev)
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{
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if (get_current()->mm != NULL)
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{
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/* userspace - relay signal, results in correct userspace timers */
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os_alarm_process(get_current()->mm->context.id.u.pid);
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}
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(*timer_clockevent.event_handler)(&timer_clockevent);
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return IRQ_HANDLED;
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}
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static u64 timer_read(struct clocksource *cs)
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{
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if (time_travel_mode != TT_MODE_OFF) {
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/*
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* We make reading the timer cost a bit so that we don't get
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* stuck in loops that expect time to move more than the
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* exact requested sleep amount, e.g. python's socket server,
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* see https://bugs.python.org/issue37026.
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*/
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time_travel_set_time(time_travel_time + TIMER_MULTIPLIER);
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return time_travel_time / TIMER_MULTIPLIER;
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}
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return os_nsecs() / TIMER_MULTIPLIER;
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}
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static struct clocksource timer_clocksource = {
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.name = "timer",
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.rating = 300,
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.read = timer_read,
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.mask = CLOCKSOURCE_MASK(64),
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.flags = CLOCK_SOURCE_IS_CONTINUOUS,
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};
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static void __init um_timer_setup(void)
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{
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int err;
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err = request_irq(TIMER_IRQ, um_timer, IRQF_TIMER, "hr timer", NULL);
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if (err != 0)
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printk(KERN_ERR "register_timer : request_irq failed - "
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"errno = %d\n", -err);
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err = os_timer_create();
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if (err != 0) {
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printk(KERN_ERR "creation of timer failed - errno = %d\n", -err);
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return;
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}
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err = clocksource_register_hz(&timer_clocksource, NSEC_PER_SEC/TIMER_MULTIPLIER);
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if (err) {
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printk(KERN_ERR "clocksource_register_hz returned %d\n", err);
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return;
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}
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clockevents_register_device(&timer_clockevent);
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}
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void read_persistent_clock64(struct timespec64 *ts)
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{
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long long nsecs;
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if (time_travel_start_set)
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nsecs = time_travel_start + time_travel_time;
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else
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nsecs = os_persistent_clock_emulation();
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set_normalized_timespec64(ts, nsecs / NSEC_PER_SEC,
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nsecs % NSEC_PER_SEC);
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}
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void __init time_init(void)
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{
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timer_set_signal_handler();
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late_time_init = um_timer_setup;
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}
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#ifdef CONFIG_UML_TIME_TRAVEL_SUPPORT
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unsigned long calibrate_delay_is_known(void)
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{
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if (time_travel_mode == TT_MODE_INFCPU)
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return 1;
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return 0;
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}
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int setup_time_travel(char *str)
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{
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if (strcmp(str, "=inf-cpu") == 0) {
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time_travel_mode = TT_MODE_INFCPU;
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timer_clockevent.name = "time-travel-timer-infcpu";
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timer_clocksource.name = "time-travel-clock";
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return 1;
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}
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if (!*str) {
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time_travel_mode = TT_MODE_BASIC;
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timer_clockevent.name = "time-travel-timer";
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timer_clocksource.name = "time-travel-clock";
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return 1;
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}
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return -EINVAL;
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}
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__setup("time-travel", setup_time_travel);
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__uml_help(setup_time_travel,
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"time-travel\n"
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"This option just enables basic time travel mode, in which the clock/timers\n"
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"inside the UML instance skip forward when there's nothing to do, rather than\n"
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"waiting for real time to elapse. However, instance CPU speed is limited by\n"
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"the real CPU speed, so e.g. a 10ms timer will always fire after ~10ms wall\n"
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"clock (but quicker when there's nothing to do).\n"
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"\n"
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"time-travel=inf-cpu\n"
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"This enables time travel mode with infinite processing power, in which there\n"
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"are no wall clock timers, and any CPU processing happens - as seen from the\n"
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"guest - instantly. This can be useful for accurate simulation regardless of\n"
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"debug overhead, physical CPU speed, etc. but is somewhat dangerous as it can\n"
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"easily lead to getting stuck (e.g. if anything in the system busy loops).\n");
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int setup_time_travel_start(char *str)
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{
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int err;
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err = kstrtoull(str, 0, &time_travel_start);
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if (err)
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return err;
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time_travel_start_set = 1;
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return 1;
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}
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__setup("time-travel-start", setup_time_travel_start);
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__uml_help(setup_time_travel_start,
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"time-travel-start=<seconds>\n"
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"Configure the UML instance's wall clock to start at this value rather than\n"
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"the host's wall clock at the time of UML boot.\n");
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#endif
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