rv: Fix 32-bit build of nomiss KUnit test

Commit 8da2a8838365 ("rv: Add KUnit tests for some DA/HA monitors")
introduced a division of a 64-bit value by 1000 in the nomiss KUnit
test. This does not

rv: Fix 32-bit build of nomiss KUnit test

Commit 8da2a8838365 ("rv: Add KUnit tests for some DA/HA monitors")
introduced a division of a 64-bit value by 1000 in the nomiss KUnit
test. This does not compile on 32-bit systems, as standard division of
64-bit values leads to an undefined reference to __udivdi3.

Fix the build on 32-bit systems by using div_u64().

Fixes: 8da2a8838365 ("rv: Add KUnit tests for some DA/HA monitors")
Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202608020311.hYjqOG5k-lkp@intel.com
Reviewed-by: Nam Cao <namcao@linutronix.de>
Link: https://lore.kernel.org/r/20260803150622.322806-1-gmonaco@redhat.com
Signed-off-by: Gabriele Monaco <gmonaco@redhat.com>

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rv: Add KUnit tests for some DA/HA monitors

Validate the functionality of DA monitors by injecting events in a
controlled environment (KUnit) and expecting reactions.

Events handlers are exported d

rv: Add KUnit tests for some DA/HA monitors

Validate the functionality of DA monitors by injecting events in a
controlled environment (KUnit) and expecting reactions.

Events handlers are exported directly from the monitor source files
without using system events and with dummy arguments (e.g. no real
tasks). If the provided sequence of events incurs a violation, the test
expects the stub version of rv_react() to be called.

This testing method can validate the entire monitor implementation since
it sits between the monitor and the system (in place of the
tracepoints). All sorts of system and timing events can be emulated
without affecting the running kernel.

Handlers and monitor functions are exported as part of a struct to
simplify the process of running KUnit tests from kernel modules.

Reviewed-by: Nam Cao <namcao@linutronix.de>
Link: https://lore.kernel.org/r/20260723074534.43521-13-gmonaco@redhat.com
Signed-off-by: Gabriele Monaco <gmonaco@redhat.com>

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rv: Simplify hybrid automata monitors's clock variables

Hybrid automata monitors's clock variables have two different
representations:

- The invariant representation, which is the timestamp when

rv: Simplify hybrid automata monitors's clock variables

Hybrid automata monitors's clock variables have two different
representations:

- The invariant representation, which is the timestamp when the invariant
expires

- The guard representation, which is the timestamp when the clock is last
reset

This dual representation makes the logic quite difficult to follow (well,
at least for me). It also complicates the monitors and the generation tool,
as it requires conversion back and forth between the representation.

Simplify by using the clock variables for a single purpose: storing the
time stamp since the clock is last reset.

This also allows simplifying rvgen, which will be done in a follow-up
commit.

Reviewed-by: Gabriele Monaco <gmonaco@redhat.com>
Signed-off-by: Nam Cao <namcao@linutronix.de>
Link: https://lore.kernel.org/r/c0f600dcbf3d8b487c944406851a39146f4d91fa.1781847583.git.namcao@linutronix.de
Signed-off-by: Gabriele Monaco <gmonaco@redhat.com>

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