[RFC PATCH v2 07/10] rv/tlob: add tlob model DOT file

[wen.yang@linux.dev]

From: Wen Yang <wen.yang@linux.dev>

Add the Graphviz DOT specification for the tlob (task latency over
budget) hybrid automaton.

The model defines three states: running (initial), waiting
(in the scheduler runqueue), and sleeping (blocked on a
resource), with the transitions:

  running  --(sleep)-------> sleeping
  running  --(preempt)-----> waiting
  sleeping --(wakeup)------> waiting
  waiting  --(switch_in)--> running

A single clock invariant clk_elapsed < BUDGET_NS() is active in all
three states.  The HA framework enforces it via a per-task hrtimer;
expiry emits error_env_tlob and resets the monitor automatically.

Suggested-by: Gabriele Monaco <gmonaco@redhat.com> 
Signed-off-by: Wen Yang <wen.yang@linux.dev>
---
 MAINTAINERS                        |  3 +++
 tools/verification/models/tlob.dot | 21 +++++++++++++++++++++
 2 files changed, 24 insertions(+)
 create mode 100644 tools/verification/models/tlob.dot

diff --git a/MAINTAINERS b/MAINTAINERS
index 74c86cf9bc65..beb7224d08ef 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -23317,7 +23317,10 @@ S:	Maintained
 F:	Documentation/trace/rv/
 F:	include/linux/rv.h
 F:	include/rv/
+F:	include/uapi/linux/rv.h
 F:	kernel/trace/rv/
+F:	samples/rv/
+F:	tools/testing/selftests/rv/
 F:	tools/testing/selftests/verification/
 F:	tools/verification/
 
diff --git a/tools/verification/models/tlob.dot b/tools/verification/models/tlob.dot
new file mode 100644
index 000000000000..8421b1120e80
--- /dev/null
+++ b/tools/verification/models/tlob.dot
@@ -0,0 +1,21 @@
+digraph state_automaton {
+	center = true;
+	size = "7,11";
+	{node [shape = plaintext, style=invis, label=""] "__init_running"};
+	{node [shape = ellipse] "running"};
+	{node [shape = plaintext] "running"};
+	{node [shape = plaintext] "waiting"};
+	{node [shape = plaintext] "sleeping"};
+	"__init_running" -> "running" [ label = "reset(clk_elapsed)" ];
+	"running"  [label = "running\nclk_elapsed < BUDGET_NS()",  color = green3];
+	"waiting"  [label = "waiting\nclk_elapsed < BUDGET_NS()"];
+	"sleeping" [label = "sleeping\nclk_elapsed < BUDGET_NS()"];
+	"running"  -> "sleeping" [ label = "sleep" ];
+	"running"  -> "waiting"  [ label = "preempt" ];
+	"waiting"  -> "running"  [ label = "switch_in" ];
+	"sleeping" -> "waiting"  [ label = "wakeup" ];
+	{ rank = min ;
+		"__init_running";
+		"running";
+	}
+}
-- 
2.25.1