@@ -191,6 +191,7 @@ config UML_TIME_TRAVEL_SUPPORT
prompt "Support time-travel mode (e.g. for test execution)"
# inf-cpu mode is incompatible with the benchmarking
depends on !RAID6_PQ_BENCHMARK
+ depends on !SMP
help
Enable this option to support time travel inside the UML instance.
@@ -6,6 +6,7 @@
#ifndef __TIMER_INTERNAL_H__
#define __TIMER_INTERNAL_H__
+#include <linux/list.h>
#define TIMER_MULTIPLIER 256
#define TIMER_MIN_DELTA 500
@@ -16,61 +17,35 @@ enum time_travel_mode {
TT_MODE_INFCPU,
};
-enum time_travel_timer_mode {
- TT_TMR_DISABLED,
- TT_TMR_ONESHOT,
- TT_TMR_PERIODIC,
+#ifdef CONFIG_UML_TIME_TRAVEL_SUPPORT
+struct time_travel_event {
+ unsigned long long time;
+ void (*fn)(struct time_travel_event *d);
+ struct list_head list;
+ bool pending, onstack;
};
-#ifdef CONFIG_UML_TIME_TRAVEL_SUPPORT
extern enum time_travel_mode time_travel_mode;
-extern unsigned long long time_travel_time;
-extern enum time_travel_timer_mode time_travel_timer_mode;
-extern unsigned long long time_travel_timer_expiry;
-extern unsigned long long time_travel_timer_interval;
-static inline void time_travel_set_time(unsigned long long ns)
-{
- time_travel_time = ns;
-}
+void time_travel_sleep(unsigned long long duration);
-static inline void time_travel_set_timer_mode(enum time_travel_timer_mode mode)
+static inline void
+time_travel_set_event_fn(struct time_travel_event *e,
+ void (*fn)(struct time_travel_event *d))
{
- time_travel_timer_mode = mode;
-}
-
-static inline void time_travel_set_timer_expiry(unsigned long long expiry)
-{
- time_travel_timer_expiry = expiry;
-}
-
-static inline void time_travel_set_timer_interval(unsigned long long interval)
-{
- time_travel_timer_interval = interval;
+ e->fn = fn;
}
#else
-#define time_travel_mode TT_MODE_OFF
-#define time_travel_time 0
-#define time_travel_timer_expiry 0
-#define time_travel_timer_interval 0
-
-static inline void time_travel_set_time(unsigned long long ns)
-{
-}
-
-static inline void time_travel_set_timer_mode(enum time_travel_timer_mode mode)
-{
-}
+struct time_travel_event {
+};
-static inline void time_travel_set_timer_expiry(unsigned long long expiry)
-{
-}
+#define time_travel_mode TT_MODE_OFF
-static inline void time_travel_set_timer_interval(unsigned long long interval)
+static inline void time_travel_sleep(unsigned long long duration)
{
}
-#define time_travel_timer_mode TT_TMR_DISABLED
-#endif
-
-#endif
+/* this is a macro so the event/function need not exist */
+#define time_travel_set_event_fn(e, fn) do {} while (0)
+#endif /* CONFIG_UML_TIME_TRAVEL_SUPPORT */
+#endif /* __TIMER_INTERNAL_H__ */
@@ -203,43 +203,6 @@ void initial_thread_cb(void (*proc)(void *), void *arg)
kmalloc_ok = save_kmalloc_ok;
}
-static void time_travel_sleep(unsigned long long duration)
-{
- unsigned long long next = time_travel_time + duration;
-
- if (time_travel_mode != TT_MODE_INFCPU)
- os_timer_disable();
-
- while (time_travel_timer_mode == TT_TMR_PERIODIC &&
- time_travel_timer_expiry < time_travel_time)
- time_travel_set_timer_expiry(time_travel_timer_expiry +
- time_travel_timer_interval);
-
- if (time_travel_timer_mode != TT_TMR_DISABLED &&
- time_travel_timer_expiry < next) {
- if (time_travel_timer_mode == TT_TMR_ONESHOT)
- time_travel_set_timer_mode(TT_TMR_DISABLED);
- /*
- * In basic mode, time_travel_time will be adjusted in
- * the timer IRQ handler so it works even when the signal
- * comes from the OS timer, see there.
- */
- if (time_travel_mode != TT_MODE_BASIC)
- time_travel_set_time(time_travel_timer_expiry);
-
- deliver_alarm();
- } else {
- time_travel_set_time(next);
- }
-
- if (time_travel_mode != TT_MODE_INFCPU) {
- if (time_travel_timer_mode == TT_TMR_PERIODIC)
- os_timer_set_interval(time_travel_timer_interval);
- else if (time_travel_timer_mode == TT_TMR_ONESHOT)
- os_timer_one_shot(time_travel_timer_expiry - next);
- }
-}
-
static void um_idle_sleep(void)
{
unsigned long long duration = UM_NSEC_PER_SEC;
@@ -4,6 +4,7 @@
* Copyright (C) 2015 Thomas Meyer (thomas@m3y3r.de)
* Copyright (C) 2012-2014 Cisco Systems
* Copyright (C) 2000 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
+ * Copyright (C) 2019 Intel Corporation
*/
#include <linux/clockchips.h>
@@ -23,16 +24,201 @@
#ifdef CONFIG_UML_TIME_TRAVEL_SUPPORT
enum time_travel_mode time_travel_mode;
-unsigned long long time_travel_time;
-enum time_travel_timer_mode time_travel_timer_mode;
-unsigned long long time_travel_timer_expiry;
-unsigned long long time_travel_timer_interval;
static bool time_travel_start_set;
static unsigned long long time_travel_start;
-#else
+static unsigned long long time_travel_time;
+static LIST_HEAD(time_travel_events);
+static unsigned long long time_travel_timer_interval;
+static unsigned long long time_travel_next_event;
+static struct time_travel_event time_travel_timer_event;
+
+static void time_travel_set_time(unsigned long long ns)
+{
+ if (unlikely(ns < time_travel_time))
+ panic("time-travel: time goes backwards %lld -> %lld\n",
+ time_travel_time, ns);
+ time_travel_time = ns;
+}
+
+static struct time_travel_event *time_travel_first_event(void)
+{
+ return list_first_entry_or_null(&time_travel_events,
+ struct time_travel_event,
+ list);
+}
+
+static void __time_travel_add_event(struct time_travel_event *e,
+ unsigned long long time)
+{
+ struct time_travel_event *tmp;
+ bool inserted = false;
+
+ if (WARN(time_travel_mode == TT_MODE_BASIC &&
+ e != &time_travel_timer_event,
+ "only timer events can be handled in basic mode"))
+ return;
+
+ if (e->pending)
+ return;
+
+ e->pending = true;
+ e->time = time;
+
+ list_for_each_entry(tmp, &time_travel_events, list) {
+ /*
+ * Add the new entry before one with higher time,
+ * or if they're equal and both on stack, because
+ * in that case we need to unwind the stack in the
+ * right order, and the later event (timer sleep
+ * or such) must be dequeued first.
+ */
+ if ((tmp->time > e->time) ||
+ (tmp->time == e->time && tmp->onstack && e->onstack)) {
+ list_add_tail(&e->list, &tmp->list);
+ inserted = true;
+ break;
+ }
+ }
+
+ if (!inserted)
+ list_add_tail(&e->list, &time_travel_events);
+
+ tmp = time_travel_first_event();
+ time_travel_next_event = tmp->time;
+}
+
+static void time_travel_add_event(struct time_travel_event *e,
+ unsigned long long time)
+{
+ if (WARN_ON(!e->fn))
+ return;
+
+ __time_travel_add_event(e, time);
+}
+
+void time_travel_periodic_timer(struct time_travel_event *e)
+{
+ time_travel_add_event(&time_travel_timer_event,
+ time_travel_time + time_travel_timer_interval);
+ deliver_alarm();
+}
+
+static void time_travel_deliver_event(struct time_travel_event *e)
+{
+ /* this is basically just deliver_alarm(), handles IRQs itself */
+ e->fn(e);
+}
+
+static bool time_travel_del_event(struct time_travel_event *e)
+{
+ if (!e->pending)
+ return false;
+ list_del(&e->list);
+ e->pending = false;
+ return true;
+}
+
+static void time_travel_update_time(unsigned long long next, bool retearly)
+{
+ struct time_travel_event ne = {
+ .onstack = true,
+ };
+ struct time_travel_event *e;
+ bool finished = retearly;
+
+ /* add it without a handler - we deal with that specifically below */
+ __time_travel_add_event(&ne, next);
+
+ do {
+ e = time_travel_first_event();
+
+ BUG_ON(!e);
+ time_travel_set_time(e->time);
+
+ /* new events may have been inserted while we were waiting */
+ if (e == time_travel_first_event()) {
+ BUG_ON(!time_travel_del_event(e));
+ BUG_ON(time_travel_time != e->time);
+
+ if (e == &ne) {
+ finished = true;
+ } else {
+ if (e->onstack)
+ panic("On-stack event dequeued outside of the stack! time=%lld, event time=%lld, event=%pS\n",
+ time_travel_time, e->time, e);
+ time_travel_deliver_event(e);
+ }
+ }
+ } while (!finished);
+
+ time_travel_del_event(&ne);
+}
+
+static void time_travel_oneshot_timer(struct time_travel_event *e)
+{
+ deliver_alarm();
+}
+
+void time_travel_sleep(unsigned long long duration)
+{
+ unsigned long long next = time_travel_time + duration;
+
+ if (time_travel_mode == TT_MODE_BASIC)
+ os_timer_disable();
+
+ time_travel_update_time(next, true);
+
+ if (time_travel_mode == TT_MODE_BASIC &&
+ time_travel_timer_event.pending) {
+ if (time_travel_timer_event.fn == time_travel_periodic_timer) {
+ /*
+ * This is somewhat wrong - we should get the first
+ * one sooner like the os_timer_one_shot() below...
+ */
+ os_timer_set_interval(time_travel_timer_interval);
+ } else {
+ os_timer_one_shot(time_travel_timer_event.time - next);
+ }
+ }
+}
+
+static void time_travel_handle_real_alarm(void)
+{
+ time_travel_set_time(time_travel_next_event);
+
+ time_travel_del_event(&time_travel_timer_event);
+
+ if (time_travel_timer_event.fn == time_travel_periodic_timer)
+ time_travel_add_event(&time_travel_timer_event,
+ time_travel_time +
+ time_travel_timer_interval);
+}
+
+static void time_travel_set_interval(unsigned long long interval)
+{
+ time_travel_timer_interval = interval;
+}
+#else /* CONFIG_UML_TIME_TRAVEL_SUPPORT */
#define time_travel_start_set 0
#define time_travel_start 0
+#define time_travel_time 0
+
+static inline void time_travel_update_time(unsigned long long ns, bool retearly)
+{
+}
+
+static inline void time_travel_handle_real_alarm(void)
+{
+}
+
+static void time_travel_set_interval(unsigned long long interval)
+{
+}
+
+/* these are empty macros so the struct/fn need not exist */
+#define time_travel_add_event(e, time) do { } while (0)
+#define time_travel_del_event(e) do { } while (0)
#endif
void timer_handler(int sig, struct siginfo *unused_si, struct uml_pt_regs *regs)
@@ -48,7 +234,7 @@ void timer_handler(int sig, struct siginfo *unused_si, struct uml_pt_regs *regs)
* never get any real signals from the OS.
*/
if (time_travel_mode == TT_MODE_BASIC)
- time_travel_set_time(time_travel_timer_expiry);
+ time_travel_handle_real_alarm();
local_irq_save(flags);
do_IRQ(TIMER_IRQ, regs);
@@ -58,7 +244,7 @@ void timer_handler(int sig, struct siginfo *unused_si, struct uml_pt_regs *regs)
static int itimer_shutdown(struct clock_event_device *evt)
{
if (time_travel_mode != TT_MODE_OFF)
- time_travel_set_timer_mode(TT_TMR_DISABLED);
+ time_travel_del_event(&time_travel_timer_event);
if (time_travel_mode != TT_MODE_INFCPU)
os_timer_disable();
@@ -71,9 +257,12 @@ static int itimer_set_periodic(struct clock_event_device *evt)
unsigned long long interval = NSEC_PER_SEC / HZ;
if (time_travel_mode != TT_MODE_OFF) {
- time_travel_set_timer_mode(TT_TMR_PERIODIC);
- time_travel_set_timer_expiry(time_travel_time + interval);
- time_travel_set_timer_interval(interval);
+ time_travel_del_event(&time_travel_timer_event);
+ time_travel_set_event_fn(&time_travel_timer_event,
+ time_travel_periodic_timer);
+ time_travel_set_interval(interval);
+ time_travel_add_event(&time_travel_timer_event,
+ time_travel_time + interval);
}
if (time_travel_mode != TT_MODE_INFCPU)
@@ -88,8 +277,11 @@ static int itimer_next_event(unsigned long delta,
delta += 1;
if (time_travel_mode != TT_MODE_OFF) {
- time_travel_set_timer_mode(TT_TMR_ONESHOT);
- time_travel_set_timer_expiry(time_travel_time + delta);
+ time_travel_del_event(&time_travel_timer_event);
+ time_travel_set_event_fn(&time_travel_timer_event,
+ time_travel_oneshot_timer);
+ time_travel_add_event(&time_travel_timer_event,
+ time_travel_time + delta);
}
if (time_travel_mode != TT_MODE_INFCPU)
@@ -144,7 +336,10 @@ static u64 timer_read(struct clocksource *cs)
* exact requested sleep amount, e.g. python's socket server,
* see https://bugs.python.org/issue37026.
*/
- time_travel_set_time(time_travel_time + TIMER_MULTIPLIER);
+ if (!irqs_disabled())
+ time_travel_update_time(time_travel_time +
+ TIMER_MULTIPLIER,
+ false);
return time_travel_time / TIMER_MULTIPLIER;
}