Formally, a deterministic automaton, denoted by G, is defined as a
quintuple:

  G = { X, E, f, x_0, X_m }

where:
	- X is the set of states;
	- E is the finite set of events;
	- x_0 is the initial state;
	- X_m (subset of X) is the set of marked states.
	- f : X x E -> X $ is the transition function. It defines the
	  state transition in the occurrence of a event from E in
	  the state X. In the special case of deterministic automata,
	  the occurrence of the event in E in a state in X has a
	  deterministic next state from X.

An automaton can also be represented using a graphical format of
vertices (nodes) and edges. The open-source tool Graphviz can produce
this graphic format using the (textual) DOT language as the source code.

The dot2c tool presented in this paper:

DE OLIVEIRA, Daniel Bristot; CUCINOTTA, Tommaso; DE OLIVEIRA, Romulo
Silva. Efficient formal verification for the Linux kernel. In:
International Conference on Software Engineering and Formal Methods.
Springer, Cham, 2019. p. 315-332.

Translates a deterministic automaton in the DOT format into a C
source code representation that to be used for monitoring.

This header file implements helper functions to facilitate the usage
of the C output from dot2c for monitoring.

Cc: Wim Van Sebroeck <wim@linux-watchdog.org>
Cc: Guenter Roeck <linux@roeck-us.net>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Will Deacon <will@kernel.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Marco Elver <elver@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: "Paul E. McKenney" <paulmck@kernel.org>
Cc: Shuah Khan <skhan@linuxfoundation.org>
Cc: Gabriele Paoloni <gpaoloni@redhat.com>
Cc: Juri Lelli <juri.lelli@redhat.com>
Cc: Clark Williams <williams@redhat.com>
Cc: linux-doc@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Cc: linux-trace-devel@vger.kernel.org
Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org>
---
 include/rv/automata.h | 49 +++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 49 insertions(+)
 create mode 100644 include/rv/automata.h

diff --git a/include/rv/automata.h b/include/rv/automata.h
new file mode 100644
index 000000000000..0c0aa54bd820
--- /dev/null
+++ b/include/rv/automata.h
@@ -0,0 +1,49 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Deterministic automata helper functions, to be used with the automata
+ * models in C generated by the dot2k tool.
+ *
+ * Copyright (C) 2019-2022 Daniel Bristot de Oliveira <bristot@kernel.org>
+ */
+
+#define DECLARE_AUTOMATA_HELPERS(name, type)					\
+										\
+static inline void *model_get_model_##name(void)				\
+{										\
+	return (void *) &automaton_##name;					\
+}										\
+										\
+static char *model_get_state_name_##name(enum states_##name state)		\
+{										\
+	return automaton_##name.state_names[state];				\
+}										\
+										\
+static char *model_get_event_name_##name(enum events_##name event)		\
+{										\
+	return automaton_##name.event_names[event];				\
+}										\
+										\
+static inline type model_get_init_state_##name(void)				\
+{										\
+	return automaton_##name.initial_state;					\
+}										\
+										\
+static inline type model_get_next_state_##name(enum states_##name curr_state,	\
+					       enum events_##name event)	\
+{										\
+	if ((curr_state < 0) || (curr_state > state_max_##name))		\
+		return -1;							\
+										\
+	if ((event < 0) || (event > event_max_##name))				\
+		return -1;							\
+										\
+	return automaton_##name.function[curr_state][event];			\
+}										\
+										\
+static inline bool model_is_final_state_##name(enum states_##name state)	\
+{										\
+	if ((state < 0) || (state > state_max_##name))				\
+		return 0;							\
+										\
+	return !!automaton_##name.final_states[state];				\
+}
-- 
2.35.1

On Thu, Jun 16, 2022 at 10:44:45AM +0200, Daniel Bristot de Oliveira wrote:

> Formally, a deterministic automaton, denoted by G, is defined as a
> quintuple:
> 
>   G = { X, E, f, x_0, X_m }
> 
> where:
> 	- X is the set of states;
> 	- E is the finite set of events;
> 	- x_0 is the initial state;
> 	- X_m (subset of X) is the set of marked states.
> 	- f : X x E -> X $ is the transition function. It defines the
> 	  state transition in the occurrence of a event from E in
> 	  the state X. In the special case of deterministic automata,
> 	  the occurrence of the event in E in a state in X has a
> 	  deterministic next state from X.
> 
> An automaton can also be represented using a graphical format of
> vertices (nodes) and edges. The open-source tool Graphviz can produce
> this graphic format using the (textual) DOT language as the source code.
> 
> The dot2c tool presented in this paper:
> 
> DE OLIVEIRA, Daniel Bristot; CUCINOTTA, Tommaso; DE OLIVEIRA, Romulo
> Silva. Efficient formal verification for the Linux kernel. In:
> International Conference on Software Engineering and Formal Methods.
> Springer, Cham, 2019. p. 315-332.
> 
> Translates a deterministic automaton in the DOT format into a C
> surce code representation that to be used for monitoring.
> 
> This header file implements helper functions to facilitate the usage
> of the C output from dot2c for monitoring.
> 
> Cc: Wim Van Sebroeck <wim@linux-watchdog.org>
> Cc: Guenter Roeck <linux@roeck-us.net>
> Cc: Jonathan Corbet <corbet@lwn.net>
> Cc: Steven Rostedt <rostedt@goodmis.org>
> Cc: Ingo Molnar <mingo@redhat.com>
> Cc: Thomas Gleixner <tglx@linutronix.de>
> Cc: Peter Zijlstra <peterz@infradead.org>
> Cc: Will Deacon <will@kernel.org>
> Cc: Catalin Marinas <catalin.marinas@arm.com>
> Cc: Marco Elver <elver@google.com>
> Cc: Dmitry Vyukov <dvyukov@google.com>
> Cc: "Paul E. McKenney" <paulmck@kernel.org>
> Cc: Shuah Khan <skhan@linuxfoundation.org>
> Cc: Gabriele Paoloni <gpaoloni@redhat.com>
> Cc: Juri Lelli <juri.lelli@redhat.com>
> Cc: Clark Williams <williams@redhat.com>
> Cc: linux-doc@vger.kernel.org
> Cc: linux-kernel@vger.kernel.org
> Cc: linux-trace-devel@vger.kernel.org
> Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org>
> ---
>  include/rv/automata.h | 49 +++++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 49 insertions(+)
>  create mode 100644 include/rv/automata.h
> 
> diff --git a/include/rv/automata.h b/include/rv/automata.h
> new file mode 100644
> index 000000000000..0c0aa54bd820
> --- /dev/null
> +++ b/include/rv/automata.h
> @@ -0,0 +1,49 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +/*
> + * Deterministic automata helper functions, to be used with the automata
> + * models in C generated by the dot2k tool.
> + *
> + * Copyright (C) 2019-2022 Daniel Bristot de Oliveira <bristot@kernel.org>
> + */
> +
> +#define DECLARE_AUTOMATA_HELPERS(name, type)					\
> +										\
> +static inline void *model_get_model_##name(void)				\
> +{										\
> +	return (void *) &automaton_##name;					\
> +}									\
> +										\
> +static char *model_get_state_name_##name(enum states_##name state)		\
> +{										\
> +	return automaton_##name.state_names[state];				\
> +}										\
> +										\
> +static char *model_get_event_name_##name(enum events_##name event)		\
> +{										\
> +	return automaton_##name.event_names[event];				\
> +}										\
> +										\
> +static inline type model_get_init_state_##name(void)				\
> +{										\
> +	return automaton_##name.initial_state;					\
> +}										\
> +										\
> +static inline type model_get_next_state_##name(enum states_##name curr_state,	\
> +					       enum events_##name event)	\
> +{										\
> +	if ((curr_state < 0) || (curr_state > state_max_##name))		\
> +		return -1;							\

curr_state can not be state_max_xxx. curr_state must be not bigger
than state_max_xxx. Or am I miss something?

> +	if ((event < 0) || (event > event_max_##name))				\
> +		return -1;							\
> +										\

Same here for the event boundary check.

> +	return automaton_##name.function[curr_state][event];			\
> +}										\
> +										\
> +static inline bool model_is_final_state_##name(enum states_##name state)	\
> +{										\
> +	if ((state < 0) || (state > state_max_##name))				\
> +		return 0;							\
> +										\

Same here.

> +	return !!automaton_##name.final_states[state];				\

If the value of .final_states[state] is 0 or 1, can the type of
.final_states[state] be befined to bool. Or not need to use !! to
explicitly transfer the type to bool. I remember that you define
this as char array and the matrix model value of this array is 0 or 1
see from the next patche. 1 delegate the state it is the initial state.
0 for others.

> +}
> -- 
> 2.35.1
>

On 7/6/22 20:35, Tao Zhou wrote:
> On Thu, Jun 16, 2022 at 10:44:45AM +0200, Daniel Bristot de Oliveira wrote:
> 
>> Formally, a deterministic automaton, denoted by G, is defined as a
>> quintuple:
>>
>>   G = { X, E, f, x_0, X_m }
>>
>> where:
>> 	- X is the set of states;
>> 	- E is the finite set of events;
>> 	- x_0 is the initial state;
>> 	- X_m (subset of X) is the set of marked states.
>> 	- f : X x E -> X $ is the transition function. It defines the
>> 	  state transition in the occurrence of a event from E in
>> 	  the state X. In the special case of deterministic automata,
>> 	  the occurrence of the event in E in a state in X has a
>> 	  deterministic next state from X.
>>
>> An automaton can also be represented using a graphical format of
>> vertices (nodes) and edges. The open-source tool Graphviz can produce
>> this graphic format using the (textual) DOT language as the source code.
>>
>> The dot2c tool presented in this paper:
>>
>> DE OLIVEIRA, Daniel Bristot; CUCINOTTA, Tommaso; DE OLIVEIRA, Romulo
>> Silva. Efficient formal verification for the Linux kernel. In:
>> International Conference on Software Engineering and Formal Methods.
>> Springer, Cham, 2019. p. 315-332.
>>
>> Translates a deterministic automaton in the DOT format into a C
>> surce code representation that to be used for monitoring.
>>
>> This header file implements helper functions to facilitate the usage
>> of the C output from dot2c for monitoring.
>>
>> Cc: Wim Van Sebroeck <wim@linux-watchdog.org>
>> Cc: Guenter Roeck <linux@roeck-us.net>
>> Cc: Jonathan Corbet <corbet@lwn.net>
>> Cc: Steven Rostedt <rostedt@goodmis.org>
>> Cc: Ingo Molnar <mingo@redhat.com>
>> Cc: Thomas Gleixner <tglx@linutronix.de>
>> Cc: Peter Zijlstra <peterz@infradead.org>
>> Cc: Will Deacon <will@kernel.org>
>> Cc: Catalin Marinas <catalin.marinas@arm.com>
>> Cc: Marco Elver <elver@google.com>
>> Cc: Dmitry Vyukov <dvyukov@google.com>
>> Cc: "Paul E. McKenney" <paulmck@kernel.org>
>> Cc: Shuah Khan <skhan@linuxfoundation.org>
>> Cc: Gabriele Paoloni <gpaoloni@redhat.com>
>> Cc: Juri Lelli <juri.lelli@redhat.com>
>> Cc: Clark Williams <williams@redhat.com>
>> Cc: linux-doc@vger.kernel.org
>> Cc: linux-kernel@vger.kernel.org
>> Cc: linux-trace-devel@vger.kernel.org
>> Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org>
>> ---
>>  include/rv/automata.h | 49 +++++++++++++++++++++++++++++++++++++++++++
>>  1 file changed, 49 insertions(+)
>>  create mode 100644 include/rv/automata.h
>>
>> diff --git a/include/rv/automata.h b/include/rv/automata.h
>> new file mode 100644
>> index 000000000000..0c0aa54bd820
>> --- /dev/null
>> +++ b/include/rv/automata.h
>> @@ -0,0 +1,49 @@
>> +/* SPDX-License-Identifier: GPL-2.0 */
>> +/*
>> + * Deterministic automata helper functions, to be used with the automata
>> + * models in C generated by the dot2k tool.
>> + *
>> + * Copyright (C) 2019-2022 Daniel Bristot de Oliveira <bristot@kernel.org>
>> + */
>> +
>> +#define DECLARE_AUTOMATA_HELPERS(name, type)					\
>> +										\
>> +static inline void *model_get_model_##name(void)				\
>> +{										\
>> +	return (void *) &automaton_##name;					\
>> +}									\
>> +										\
>> +static char *model_get_state_name_##name(enum states_##name state)		\
>> +{										\
>> +	return automaton_##name.state_names[state];				\
>> +}										\
>> +										\
>> +static char *model_get_event_name_##name(enum events_##name event)		\
>> +{										\
>> +	return automaton_##name.event_names[event];				\
>> +}										\
>> +										\
>> +static inline type model_get_init_state_##name(void)				\
>> +{										\
>> +	return automaton_##name.initial_state;					\
>> +}										\
>> +										\
>> +static inline type model_get_next_state_##name(enum states_##name curr_state,	\
>> +					       enum events_##name event)	\
>> +{										\
>> +	if ((curr_state < 0) || (curr_state > state_max_##name))		\
>> +		return -1;							\
> 
> curr_state can not be state_max_xxx. curr_state must be not bigger
> than state_max_xxx. Or am I miss something?
> 
>> +	if ((event < 0) || (event > event_max_##name))				\
>> +		return -1;							\
>> +										\
> 
> Same here for the event boundary check.
> 
>> +	return automaton_##name.function[curr_state][event];			\
>> +}										\
>> +										\
>> +static inline bool model_is_final_state_##name(enum states_##name state)	\
>> +{										\
>> +	if ((state < 0) || (state > state_max_##name))				\
>> +		return 0;							\
>> +										\
> 
> Same here.
> 
>> +	return !!automaton_##name.final_states[state];				\
> 
> If the value of .final_states[state] is 0 or 1, can the type of
> .final_states[state] be befined to bool. Or not need to use !! to
> explicitly transfer the type to bool. I remember that you define
> this as char array and the matrix model value of this array is 0 or 1
> see from the next patche. 1 delegate the state it is the initial state.
> 0 for others.

All points addressed!
-- Daniel

On Thu, 16 Jun 2022 10:44:45 +0200
Daniel Bristot de Oliveira <bristot@kernel.org> wrote:

> Formally, a deterministic automaton, denoted by G, is defined as a
> quintuple:
> 
>   G = { X, E, f, x_0, X_m }
> 
> where:
> 	- X is the set of states;
> 	- E is the finite set of events;
> 	- x_0 is the initial state;
> 	- X_m (subset of X) is the set of marked states.
> 	- f : X x E -> X $ is the transition function. It defines the
> 	  state transition in the occurrence of a event from E in
> 	  the state X. In the special case of deterministic automata,
> 	  the occurrence of the event in E in a state in X has a
> 	  deterministic next state from X.
> 
> An automaton can also be represented using a graphical format of
> vertices (nodes) and edges. The open-source tool Graphviz can produce
> this graphic format using the (textual) DOT language as the source code.
> 
> The dot2c tool presented in this paper:
> 
> DE OLIVEIRA, Daniel Bristot; CUCINOTTA, Tommaso; DE OLIVEIRA, Romulo
> Silva. Efficient formal verification for the Linux kernel. In:
> International Conference on Software Engineering and Formal Methods.
> Springer, Cham, 2019. p. 315-332.
> 
> Translates a deterministic automaton in the DOT format into a C
> source code representation that to be used for monitoring.
> 
> This header file implements helper functions to facilitate the usage
> of the C output from dot2c for monitoring.
> 
> Cc: Wim Van Sebroeck <wim@linux-watchdog.org>
> Cc: Guenter Roeck <linux@roeck-us.net>
> Cc: Jonathan Corbet <corbet@lwn.net>
> Cc: Steven Rostedt <rostedt@goodmis.org>
> Cc: Ingo Molnar <mingo@redhat.com>
> Cc: Thomas Gleixner <tglx@linutronix.de>
> Cc: Peter Zijlstra <peterz@infradead.org>
> Cc: Will Deacon <will@kernel.org>
> Cc: Catalin Marinas <catalin.marinas@arm.com>
> Cc: Marco Elver <elver@google.com>
> Cc: Dmitry Vyukov <dvyukov@google.com>
> Cc: "Paul E. McKenney" <paulmck@kernel.org>
> Cc: Shuah Khan <skhan@linuxfoundation.org>
> Cc: Gabriele Paoloni <gpaoloni@redhat.com>
> Cc: Juri Lelli <juri.lelli@redhat.com>
> Cc: Clark Williams <williams@redhat.com>
> Cc: linux-doc@vger.kernel.org
> Cc: linux-kernel@vger.kernel.org
> Cc: linux-trace-devel@vger.kernel.org
> Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org>
> ---
>  include/rv/automata.h | 49 +++++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 49 insertions(+)
>  create mode 100644 include/rv/automata.h
> 
> diff --git a/include/rv/automata.h b/include/rv/automata.h
> new file mode 100644
> index 000000000000..0c0aa54bd820
> --- /dev/null
> +++ b/include/rv/automata.h
> @@ -0,0 +1,49 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +/*
> + * Deterministic automata helper functions, to be used with the automata
> + * models in C generated by the dot2k tool.
> + *
> + * Copyright (C) 2019-2022 Daniel Bristot de Oliveira <bristot@kernel.org>

Copyright before the description.

> + */
> +

There should be comments here describing how the helper functions are used.

-- Steve

> +#define DECLARE_AUTOMATA_HELPERS(name, type)					\
> +										\
> +static inline void *model_get_model_##name(void)				\
> +{										\
> +	return (void *) &automaton_##name;					\
> +}										\
> +										\
> +static char *model_get_state_name_##name(enum states_##name state)		\
> +{										\
> +	return automaton_##name.state_names[state];				\
> +}										\
> +										\
> +static char *model_get_event_name_##name(enum events_##name event)		\
> +{										\
> +	return automaton_##name.event_names[event];				\
> +}										\
> +										\
> +static inline type model_get_init_state_##name(void)				\
> +{										\
> +	return automaton_##name.initial_state;					\
> +}										\
> +										\
> +static inline type model_get_next_state_##name(enum states_##name curr_state,	\
> +					       enum events_##name event)	\
> +{										\
> +	if ((curr_state < 0) || (curr_state > state_max_##name))		\
> +		return -1;							\
> +										\
> +	if ((event < 0) || (event > event_max_##name))				\
> +		return -1;							\
> +										\
> +	return automaton_##name.function[curr_state][event];			\
> +}										\
> +										\
> +static inline bool model_is_final_state_##name(enum states_##name state)	\
> +{										\
> +	if ((state < 0) || (state > state_max_##name))				\
> +		return 0;							\
> +										\
> +	return !!automaton_##name.final_states[state];				\
> +}