kernel/linux.git/include/linux/rv.h, branch v6.18.21

include/linux/rv.h: remove redundant include file

2025-09-15T06:36:35+00:00

Remove redundant include to clean up the code. Move all unique include files inside CONFIG_RV as they are only needed when CONFIG_RV is enabled. Arrange include files alphabetically. Fixes: 24cbfe18d55a ("rv: Merge struct rv_monitor_def into struct rv_monitor") [1] Reported-by: kernel test robot Closes: https://lore.kernel.org/r/202507312017.oyD08TL5-lkp@intel.com/ Signed-off-by: Akhilesh Patil Reviewed-by: Gabriele Monaco Link: https://lore.kernel.org/r/aJneRbHGlNFg7lr9@bhairav-test.ee.iitb.ac.in Signed-off-by: Gabriele Monaco

rv: Retry when da monitor detects race conditions

2025-07-28T20:47:34+00:00

DA monitor can be accessed from multiple cores simultaneously, this is likely, for instance when dealing with per-task monitors reacting on events that do not always occur on the CPU where the task is running. This can cause race conditions where two events change the next state and we see inconsistent values. E.g.: [62] event_srs: 27: sleepable x sched_wakeup -> running (final) [63] event_srs: 27: sleepable x sched_set_state_sleepable -> sleepable [63] error_srs: 27: event sched_switch_suspend not expected in the state running In this case the monitor fails because the event on CPU 62 wins against the one on CPU 63, although the correct state should have been sleepable, since the task get suspended. Detect if the current state was modified by using try_cmpxchg while storing the next value. If it was, try again reading the current state. After a maximum number of failed retries, react by calling a special tracepoint, print on the console and reset the monitor. Remove the functions da_monitor_curr_state() and da_monitor_set_state() as they only hide the underlying implementation in this case. Monitors where this type of condition can occur must be able to account for racing events in any possible order, as we cannot know the winner. Cc: Ingo Molnar Cc: Masami Hiramatsu Cc: Tomas Glozar Cc: Juri Lelli Cc: Clark Williams Cc: John Kacur Cc: Peter Zijlstra Link: https://lore.kernel.org/20250728135022.255578-6-gmonaco@redhat.com Signed-off-by: Gabriele Monaco Reviewed-by: Nam Cao Signed-off-by: Steven Rostedt (Google)

rv: Remove struct rv_monitor::reacting

2025-07-25T13:04:14+00:00

The field 'reacting' in struct rv_monitor is set but never used. Delete it. Cc: Masami Hiramatsu Cc: Mathieu Desnoyers Link: https://lore.kernel.org/a6c16f845d2f1a09c4d0934ab83f3cb14478a71d.1753378331.git.namcao@linutronix.de Reviewed-by: Gabriele Monaco Signed-off-by: Nam Cao Signed-off-by: Steven Rostedt (Google)

rv: Remove rv_reactor's reference counter

2025-07-25T13:04:14+00:00

rv_reactor has a reference counter to ensure it is not removed while monitors are still using it. However, this is futile, as __exit functions are not expected to fail and will proceed normally despite rv_unregister_reactor() returning an error. At the moment, reactors do not support being built as modules, therefore they are never removed and the reference counters are not necessary. If we support building RV reactors as modules in the future, kernel module's centralized facilities such as try_module_get(), module_put() or MODULE_SOFTDEP should be used instead of this custom implementation. Remove this reference counter. Cc: Masami Hiramatsu Cc: Mathieu Desnoyers Link: https://lore.kernel.org/bb946398436a5e17fb0f5b842ef3313c02291852.1753378331.git.namcao@linutronix.de Reviewed-by: Gabriele Monaco Signed-off-by: Nam Cao Signed-off-by: Steven Rostedt (Google)

rv: Merge struct rv_reactor_def into struct rv_reactor

2025-07-25T13:04:14+00:00

Each struct rv_reactor has a unique struct rv_reactor_def associated with it. struct rv_reactor is statically allocated, while struct rv_reactor_def is dynamically allocated. This makes the code more complicated than it should be: - Lookup is required to get the associated rv_reactor_def from rv_reactor - Dynamic memory allocation is required for rv_reactor_def. This is harder to get right compared to static memory. For instance, there is an existing mistake: rv_unregister_reactor() does not free the memory allocated by rv_register_reactor(). This is fortunately not a real memory leak problem as rv_unregister_reactor() is never called. Simplify and merge rv_reactor_def into rv_reactor. Cc: Masami Hiramatsu Cc: Mathieu Desnoyers Link: https://lore.kernel.org/71cb91c86cd40df5b8c492b788787f2a73c3eaa3.1753378331.git.namcao@linutronix.de Reviewed-by: Gabriele Monaco Signed-off-by: Nam Cao Signed-off-by: Steven Rostedt (Google)

rv: Merge struct rv_monitor_def into struct rv_monitor

2025-07-25T13:04:14+00:00

Each struct rv_monitor has a unique struct rv_monitor_def associated with it. struct rv_monitor is statically allocated, while struct rv_monitor_def is dynamically allocated. This makes the code more complicated than it should be: - Lookup is required to get the associated rv_monitor_def from rv_monitor - Dynamic memory allocation is required for rv_monitor_def. This is harder to get right compared to static memory. For instance, there is an existing mistake: rv_unregister_monitor() does not free the memory allocated by rv_register_monitor(). This is fortunately not a real memory leak problem, as rv_unregister_monitor() is never called. Simplify and merge rv_monitor_def into rv_monitor. Cc: Masami Hiramatsu Cc: Mathieu Desnoyers Link: https://lore.kernel.org/194449c00f87945c207aab4c96920c75796a4f53.1753378331.git.namcao@linutronix.de Reviewed-by: Gabriele Monaco Signed-off-by: Nam Cao Signed-off-by: Steven Rostedt (Google)

rv: Allow to configure the number of per-task monitor

2025-07-09T19:27:02+00:00

Now that there are 2 monitors for real-time applications, users may want to enable both of them simultaneously. Make the number of per-task monitor configurable. Default it to 2 for now. Cc: John Ogness Cc: Masami Hiramatsu Cc: Mathieu Desnoyers Link: https://lore.kernel.org/93e83313fc4ba7f6e66f4abe80ca5f5494d658d0.1752088709.git.namcao@linutronix.de Reviewed-by: Gabriele Monaco Signed-off-by: Nam Cao Signed-off-by: Steven Rostedt (Google)

rv: Add support for LTL monitors

2025-07-09T19:27:01+00:00

While attempting to implement DA monitors for some complex specifications, deterministic automaton is found to be inappropriate as the specification language. The automaton is complicated, hard to understand, and error-prone. For these cases, linear temporal logic is more suitable as the specification language. Add support for linear temporal logic runtime verification monitor. Cc: John Ogness Cc: Masami Hiramatsu Cc: Mathieu Desnoyers Cc: Gabriele Monaco Link: https://lore.kernel.org/d366c1fed60ed4e8f6451f3c15a99755f2740b5f.1752088709.git.namcao@linutronix.de Signed-off-by: Nam Cao Signed-off-by: Steven Rostedt (Google)

rv: Let the reactors take care of buffers

2025-07-09T19:27:00+00:00

Each RV monitor has one static buffer to send to the reactors. If multiple errors are detected simultaneously, the one buffer could be overwritten. Instead, leave it to the reactors to handle buffering. Reviewed-by: Gabriele Monaco Signed-off-by: Nam Cao Signed-off-by: Steven Rostedt (Google)

rv: Add option for nested monitors and include sched

2025-03-24T21:27:39+00:00

Monitors describing complex systems, such as the scheduler, can easily grow to the point where they are just hard to understand because of the many possible state transitions. Often it is possible to break such descriptions into smaller monitors, sharing some or all events. Enabling those smaller monitors concurrently is, in fact, testing the system as if we had one single larger monitor. Splitting models into multiple specification is not only easier to understand, but gives some more clues when we see errors. Add the possibility to create container monitors, whose only purpose is to host other nested monitors. Enabling a container monitor enables all nested ones, but it's still possible to enable nested monitors independently. Add the sched monitor as first container, for now empty. Cc: Ingo Molnar Cc: Peter Zijlstra Cc: Juri Lelli Link: https://lore.kernel.org/20250305140406.350227-3-gmonaco@redhat.com Signed-off-by: Gabriele Monaco Signed-off-by: Steven Rostedt (Google)