From 09ecd8b8c585c95a3b8dbdec86c15a981fdfeba1 Mon Sep 17 00:00:00 2001 From: Daniel Bristot de Oliveira Date: Fri, 29 Jul 2022 11:38:42 +0200 Subject: [PATCH] rv/include: Add helper functions for deterministic automata 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/k for monitoring. Link: https://lkml.kernel.org/r/563234f2bfa84b540f60cf9e39c2d9f0eea95a55.1659052063.git.bristot@kernel.org Cc: Wim Van Sebroeck Cc: Guenter Roeck Cc: Jonathan Corbet Cc: Ingo Molnar Cc: Thomas Gleixner Cc: Peter Zijlstra Cc: Will Deacon Cc: Catalin Marinas Cc: Marco Elver Cc: Dmitry Vyukov Cc: "Paul E. McKenney" Cc: Shuah Khan Cc: Gabriele Paoloni Cc: Juri Lelli Cc: Clark Williams Cc: Tao Zhou Cc: Randy Dunlap 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 Signed-off-by: Steven Rostedt (Google) --- include/rv/automata.h | 75 +++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 75 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..eb9e636809a0 --- /dev/null +++ b/include/rv/automata.h @@ -0,0 +1,75 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * Copyright (C) 2019-2022 Red Hat, Inc. Daniel Bristot de Oliveira + * + * Deterministic automata helper functions, to be used with the automata + * models in C generated by the dot2k tool. + */ + +/* + * DECLARE_AUTOMATA_HELPERS - define a set of helper functions for automata + * + * Define a set of helper functions for automata. The 'name' argument is used + * as suffix for the functions and data. These functions will handle automaton + * with data type 'type'. + */ +#define DECLARE_AUTOMATA_HELPERS(name, type) \ + \ +/* \ + * model_get_state_name_##name - return the (string) name of the given state \ + */ \ +static char *model_get_state_name_##name(enum states_##name state) \ +{ \ + if ((state < 0) || (state >= state_max_##name)) \ + return "INVALID"; \ + \ + return automaton_##name.state_names[state]; \ +} \ + \ +/* \ + * model_get_event_name_##name - return the (string) name of the given event \ + */ \ +static char *model_get_event_name_##name(enum events_##name event) \ +{ \ + if ((event < 0) || (event >= event_max_##name)) \ + return "INVALID"; \ + \ + return automaton_##name.event_names[event]; \ +} \ + \ +/* \ + * model_get_initial_state_##name - return the automaton's initial state \ + */ \ +static inline type model_get_initial_state_##name(void) \ +{ \ + return automaton_##name.initial_state; \ +} \ + \ +/* \ + * model_get_next_state_##name - process an automaton event occurrence \ + * \ + * Given the current state (curr_state) and the event (event), returns \ + * the next state, or INVALID_STATE in case of error. \ + */ \ +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 INVALID_STATE; \ + \ + if ((event < 0) || (event >= event_max_##name)) \ + return INVALID_STATE; \ + \ + return automaton_##name.function[curr_state][event]; \ +} \ + \ +/* \ + * model_is_final_state_##name - check if the given state is a final state \ + */ \ +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]; \ +}