um: Implement time-travel=ext

This implements synchronized time-travel mode which - using a special
application on a unix socket - lets multiple machines take part in a
time-travelling simulation together.

The protocol for the unix domain socket is defined in the new file
include/uapi/linux/um_timetravel.h.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Richard Weinberger <richard@nod.at>

2 files changed, 28 insertions, 0 deletions

diff --git a/arch/um/include/linux/time-internal.h b/arch/um/include/linux/time-internal.h
index eb1f84616edb..e21655926f08 100644
--- a/arch/um/include/linux/time-internal.h
+++ b/arch/um/include/linux/time-internal.h
@@ -15,6 +15,7 @@ enum time_travel_mode {
 	TT_MODE_OFF,
 	TT_MODE_BASIC,
 	TT_MODE_INFCPU,
+	TT_MODE_EXTERNAL,
 };
 
 #ifdef CONFIG_UML_TIME_TRAVEL_SUPPORT
@@ -35,6 +36,24 @@ time_travel_set_event_fn(struct time_travel_event *e,
 {
 	e->fn = fn;
 }
+
+void __time_travel_propagate_time(void);
+
+static inline void time_travel_propagate_time(void)
+{
+	if (time_travel_mode == TT_MODE_EXTERNAL)
+		__time_travel_propagate_time();
+}
+
+void __time_travel_wait_readable(int fd);
+
+static inline void time_travel_wait_readable(int fd)
+{
+	if (time_travel_mode == TT_MODE_EXTERNAL)
+		__time_travel_wait_readable(fd);
+}
+
+void time_travel_add_irq_event(struct time_travel_event *e);
 #else
 struct time_travel_event {
 };
@@ -47,5 +66,13 @@ static inline void time_travel_sleep(unsigned long long duration)
 
 /* this is a macro so the event/function need not exist */
 #define time_travel_set_event_fn(e, fn) do {} while (0)
+
+static inline void time_travel_propagate_time(void)
+{
+}
+
+static inline void time_travel_wait_readable(int fd)
+{
+}
 #endif /* CONFIG_UML_TIME_TRAVEL_SUPPORT */
 #endif /* __TIMER_INTERNAL_H__ */
diff --git a/arch/um/include/shared/os.h b/arch/um/include/shared/os.h
index 0f30204b6afa..f467d28fc0b4 100644
--- a/arch/um/include/shared/os.h
+++ b/arch/um/include/shared/os.h
@@ -181,6 +181,7 @@ extern int os_falloc_punch(int fd, unsigned long long offset, int count);
 extern int os_eventfd(unsigned int initval, int flags);
 extern int os_sendmsg_fds(int fd, const void *buf, unsigned int len,
 			  const int *fds, unsigned int fds_num);
+int os_poll(unsigned int n, const int *fds);
 
 /* start_up.c */
 extern void os_early_checks(void);