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Message-ID: <9cf7711a-f36a-608d-1605-179f3037b644@kernel.org>
Date: Wed, 13 Jul 2022 20:38:59 +0200
From: Daniel Bristot de Oliveira <bristot@...nel.org>
To: Tao Zhou <tao.zhou@...ux.dev>
Cc: Steven Rostedt <rostedt@...dmis.org>,
Wim Van Sebroeck <wim@...ux-watchdog.org>,
Guenter Roeck <linux@...ck-us.net>,
Jonathan Corbet <corbet@....net>,
Ingo Molnar <mingo@...hat.com>,
Thomas Gleixner <tglx@...utronix.de>,
Peter Zijlstra <peterz@...radead.org>,
Will Deacon <will@...nel.org>,
Catalin Marinas <catalin.marinas@....com>,
Marco Elver <elver@...gle.com>,
Dmitry Vyukov <dvyukov@...gle.com>,
"Paul E. McKenney" <paulmck@...nel.org>,
Shuah Khan <skhan@...uxfoundation.org>,
Gabriele Paoloni <gpaoloni@...hat.com>,
Juri Lelli <juri.lelli@...hat.com>,
Clark Williams <williams@...hat.com>,
linux-doc@...r.kernel.org, linux-kernel@...r.kernel.org,
linux-trace-devel@...r.kernel.org
Subject: Re: [PATCH V4 03/20] rv/include: Add helper functions for
deterministic automata
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@...ux-watchdog.org>
>> Cc: Guenter Roeck <linux@...ck-us.net>
>> Cc: Jonathan Corbet <corbet@....net>
>> Cc: Steven Rostedt <rostedt@...dmis.org>
>> Cc: Ingo Molnar <mingo@...hat.com>
>> Cc: Thomas Gleixner <tglx@...utronix.de>
>> Cc: Peter Zijlstra <peterz@...radead.org>
>> Cc: Will Deacon <will@...nel.org>
>> Cc: Catalin Marinas <catalin.marinas@....com>
>> Cc: Marco Elver <elver@...gle.com>
>> Cc: Dmitry Vyukov <dvyukov@...gle.com>
>> Cc: "Paul E. McKenney" <paulmck@...nel.org>
>> Cc: Shuah Khan <skhan@...uxfoundation.org>
>> Cc: Gabriele Paoloni <gpaoloni@...hat.com>
>> Cc: Juri Lelli <juri.lelli@...hat.com>
>> Cc: Clark Williams <williams@...hat.com>
>> Cc: linux-doc@...r.kernel.org
>> Cc: linux-kernel@...r.kernel.org
>> Cc: linux-trace-devel@...r.kernel.org
>> Signed-off-by: Daniel Bristot de Oliveira <bristot@...nel.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@...nel.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
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