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authorJohannes Berg <johannes.berg@intel.com>2020-02-13 14:26:45 +0100
committerRichard Weinberger <richard@nod.at>2020-03-29 23:28:51 +0200
commit4b786e24ca80a492736b359b3d1a8d07612a78e5 (patch)
tree9339ed3ac66bec47806a03f8dbccb63cee77a57f /arch/um/Kconfig
parentf185063bff914e589b50f1b711fc42218c4790c6 (diff)
um: time-travel: Rewrite as an event scheduler
Instead of tracking all the various timer configurations, modify the time-travel mode to have an event scheduler and use a timer event on the scheduler to handle the different timer configurations. This doesn't change the function right now, but it prepares the code for having different kinds of events in the future (i.e. interrupts coming from other devices that are part of co-simulation.) While at it, also move time_travel_sleep() to time.c to reduce the externally visible API surface. Also, we really should mark time-travel as incompatible with SMP, even if UML doesn't support SMP yet. Finally, I noticed a bug while developing this - if we move time forward due to consuming time while reading the clock, we might move across the next event and that would cause us to go backward in time when we then handle that event. Fix that by invoking the whole event machine in this case, but in order to simplify this, make reading the clock only cost something when interrupts are not disabled. Otherwise, we'd have to hook into the interrupt delivery machinery etc. and that's somewhat intrusive. Signed-off-by: Johannes Berg <johannes.berg@intel.com> Signed-off-by: Richard Weinberger <richard@nod.at>
Diffstat (limited to 'arch/um/Kconfig')
-rw-r--r--arch/um/Kconfig1
1 files changed, 1 insertions, 0 deletions
diff --git a/arch/um/Kconfig b/arch/um/Kconfig
index 0917f8443c28..817a4c838a06 100644
--- a/arch/um/Kconfig
+++ b/arch/um/Kconfig
@@ -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.