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1/* SPDX-License-Identifier: GPL-2.0 */
2/*
3 * Copyright (C) 2019-2022 Red Hat, Inc. Daniel Bristot de Oliveira <bristot@kernel.org>
4 *
5 * Deterministic automata (DA) monitor functions, to be used together
6 * with automata models in C generated by the dot2k tool.
7 *
8 * The dot2k tool is available at tools/verification/dot2k/
9 *
10 * For further information, see:
11 * Documentation/trace/rv/da_monitor_synthesis.rst
12 */
13
14#include <rv/automata.h>
15#include <linux/rv.h>
16#include <linux/bug.h>
17#include <linux/sched.h>
18
19#ifdef CONFIG_RV_REACTORS
20
21#define DECLARE_RV_REACTING_HELPERS(name, type) \
22static char REACT_MSG_##name[1024]; \
23 \
24static inline char *format_react_msg_##name(type curr_state, type event) \
25{ \
26 snprintf(REACT_MSG_##name, 1024, \
27 "rv: monitor %s does not allow event %s on state %s\n", \
28 #name, \
29 model_get_event_name_##name(event), \
30 model_get_state_name_##name(curr_state)); \
31 return REACT_MSG_##name; \
32} \
33 \
34static void cond_react_##name(char *msg) \
35{ \
36 if (rv_##name.react) \
37 rv_##name.react(msg); \
38} \
39 \
40static bool rv_reacting_on_##name(void) \
41{ \
42 return rv_reacting_on(); \
43}
44
45#else /* CONFIG_RV_REACTOR */
46
47#define DECLARE_RV_REACTING_HELPERS(name, type) \
48static inline char *format_react_msg_##name(type curr_state, type event) \
49{ \
50 return NULL; \
51} \
52 \
53static void cond_react_##name(char *msg) \
54{ \
55 return; \
56} \
57 \
58static bool rv_reacting_on_##name(void) \
59{ \
60 return 0; \
61}
62#endif
63
64/*
65 * Generic helpers for all types of deterministic automata monitors.
66 */
67#define DECLARE_DA_MON_GENERIC_HELPERS(name, type) \
68 \
69DECLARE_RV_REACTING_HELPERS(name, type) \
70 \
71/* \
72 * da_monitor_reset_##name - reset a monitor and setting it to init state \
73 */ \
74static inline void da_monitor_reset_##name(struct da_monitor *da_mon) \
75{ \
76 da_mon->monitoring = 0; \
77 da_mon->curr_state = model_get_initial_state_##name(); \
78} \
79 \
80/* \
81 * da_monitor_curr_state_##name - return the current state \
82 */ \
83static inline type da_monitor_curr_state_##name(struct da_monitor *da_mon) \
84{ \
85 return da_mon->curr_state; \
86} \
87 \
88/* \
89 * da_monitor_set_state_##name - set the new current state \
90 */ \
91static inline void \
92da_monitor_set_state_##name(struct da_monitor *da_mon, enum states_##name state) \
93{ \
94 da_mon->curr_state = state; \
95} \
96 \
97/* \
98 * da_monitor_start_##name - start monitoring \
99 * \
100 * The monitor will ignore all events until monitoring is set to true. This \
101 * function needs to be called to tell the monitor to start monitoring. \
102 */ \
103static inline void da_monitor_start_##name(struct da_monitor *da_mon) \
104{ \
105 da_mon->curr_state = model_get_initial_state_##name(); \
106 da_mon->monitoring = 1; \
107} \
108 \
109/* \
110 * da_monitoring_##name - returns true if the monitor is processing events \
111 */ \
112static inline bool da_monitoring_##name(struct da_monitor *da_mon) \
113{ \
114 return da_mon->monitoring; \
115} \
116 \
117/* \
118 * da_monitor_enabled_##name - checks if the monitor is enabled \
119 */ \
120static inline bool da_monitor_enabled_##name(void) \
121{ \
122 /* global switch */ \
123 if (unlikely(!rv_monitoring_on())) \
124 return 0; \
125 \
126 /* monitor enabled */ \
127 if (unlikely(!rv_##name.enabled)) \
128 return 0; \
129 \
130 return 1; \
131} \
132 \
133/* \
134 * da_monitor_handling_event_##name - checks if the monitor is ready to handle events \
135 */ \
136static inline bool da_monitor_handling_event_##name(struct da_monitor *da_mon) \
137{ \
138 \
139 if (!da_monitor_enabled_##name()) \
140 return 0; \
141 \
142 /* monitor is actually monitoring */ \
143 if (unlikely(!da_monitoring_##name(da_mon))) \
144 return 0; \
145 \
146 return 1; \
147}
148
149/*
150 * Event handler for implicit monitors. Implicit monitor is the one which the
151 * handler does not need to specify which da_monitor to manipulate. Examples
152 * of implicit monitor are the per_cpu or the global ones.
153 */
154#define DECLARE_DA_MON_MODEL_HANDLER_IMPLICIT(name, type) \
155 \
156static inline bool \
157da_event_##name(struct da_monitor *da_mon, enum events_##name event) \
158{ \
159 type curr_state = da_monitor_curr_state_##name(da_mon); \
160 type next_state = model_get_next_state_##name(curr_state, event); \
161 \
162 if (next_state != INVALID_STATE) { \
163 da_monitor_set_state_##name(da_mon, next_state); \
164 \
165 trace_event_##name(model_get_state_name_##name(curr_state), \
166 model_get_event_name_##name(event), \
167 model_get_state_name_##name(next_state), \
168 model_is_final_state_##name(next_state)); \
169 \
170 return true; \
171 } \
172 \
173 if (rv_reacting_on_##name()) \
174 cond_react_##name(format_react_msg_##name(curr_state, event)); \
175 \
176 trace_error_##name(model_get_state_name_##name(curr_state), \
177 model_get_event_name_##name(event)); \
178 \
179 return false; \
180} \
181
182/*
183 * Event handler for per_task monitors.
184 */
185#define DECLARE_DA_MON_MODEL_HANDLER_PER_TASK(name, type) \
186 \
187static inline bool da_event_##name(struct da_monitor *da_mon, struct task_struct *tsk, \
188 enum events_##name event) \
189{ \
190 type curr_state = da_monitor_curr_state_##name(da_mon); \
191 type next_state = model_get_next_state_##name(curr_state, event); \
192 \
193 if (next_state != INVALID_STATE) { \
194 da_monitor_set_state_##name(da_mon, next_state); \
195 \
196 trace_event_##name(tsk->pid, \
197 model_get_state_name_##name(curr_state), \
198 model_get_event_name_##name(event), \
199 model_get_state_name_##name(next_state), \
200 model_is_final_state_##name(next_state)); \
201 \
202 return true; \
203 } \
204 \
205 if (rv_reacting_on_##name()) \
206 cond_react_##name(format_react_msg_##name(curr_state, event)); \
207 \
208 trace_error_##name(tsk->pid, \
209 model_get_state_name_##name(curr_state), \
210 model_get_event_name_##name(event)); \
211 \
212 return false; \
213}
214
215/*
216 * Functions to define, init and get a global monitor.
217 */
218#define DECLARE_DA_MON_INIT_GLOBAL(name, type) \
219 \
220/* \
221 * global monitor (a single variable) \
222 */ \
223static struct da_monitor da_mon_##name; \
224 \
225/* \
226 * da_get_monitor_##name - return the global monitor address \
227 */ \
228static struct da_monitor *da_get_monitor_##name(void) \
229{ \
230 return &da_mon_##name; \
231} \
232 \
233/* \
234 * da_monitor_reset_all_##name - reset the single monitor \
235 */ \
236static void da_monitor_reset_all_##name(void) \
237{ \
238 da_monitor_reset_##name(da_get_monitor_##name()); \
239} \
240 \
241/* \
242 * da_monitor_init_##name - initialize a monitor \
243 */ \
244static inline int da_monitor_init_##name(void) \
245{ \
246 da_monitor_reset_all_##name(); \
247 return 0; \
248} \
249 \
250/* \
251 * da_monitor_destroy_##name - destroy the monitor \
252 */ \
253static inline void da_monitor_destroy_##name(void) \
254{ \
255 return; \
256}
257
258/*
259 * Functions to define, init and get a per-cpu monitor.
260 */
261#define DECLARE_DA_MON_INIT_PER_CPU(name, type) \
262 \
263/* \
264 * per-cpu monitor variables \
265 */ \
266static DEFINE_PER_CPU(struct da_monitor, da_mon_##name); \
267 \
268/* \
269 * da_get_monitor_##name - return current CPU monitor address \
270 */ \
271static struct da_monitor *da_get_monitor_##name(void) \
272{ \
273 return this_cpu_ptr(&da_mon_##name); \
274} \
275 \
276/* \
277 * da_monitor_reset_all_##name - reset all CPUs' monitor \
278 */ \
279static void da_monitor_reset_all_##name(void) \
280{ \
281 struct da_monitor *da_mon; \
282 int cpu; \
283 for_each_cpu(cpu, cpu_online_mask) { \
284 da_mon = per_cpu_ptr(&da_mon_##name, cpu); \
285 da_monitor_reset_##name(da_mon); \
286 } \
287} \
288 \
289/* \
290 * da_monitor_init_##name - initialize all CPUs' monitor \
291 */ \
292static inline int da_monitor_init_##name(void) \
293{ \
294 da_monitor_reset_all_##name(); \
295 return 0; \
296} \
297 \
298/* \
299 * da_monitor_destroy_##name - destroy the monitor \
300 */ \
301static inline void da_monitor_destroy_##name(void) \
302{ \
303 return; \
304}
305
306/*
307 * Functions to define, init and get a per-task monitor.
308 */
309#define DECLARE_DA_MON_INIT_PER_TASK(name, type) \
310 \
311/* \
312 * The per-task monitor is stored a vector in the task struct. This variable \
313 * stores the position on the vector reserved for this monitor. \
314 */ \
315static int task_mon_slot_##name = RV_PER_TASK_MONITOR_INIT; \
316 \
317/* \
318 * da_get_monitor_##name - return the monitor in the allocated slot for tsk \
319 */ \
320static inline struct da_monitor *da_get_monitor_##name(struct task_struct *tsk) \
321{ \
322 return &tsk->rv[task_mon_slot_##name].da_mon; \
323} \
324 \
325static void da_monitor_reset_all_##name(void) \
326{ \
327 struct task_struct *g, *p; \
328 int cpu; \
329 \
330 read_lock(&tasklist_lock); \
331 for_each_process_thread(g, p) \
332 da_monitor_reset_##name(da_get_monitor_##name(p)); \
333 for_each_present_cpu(cpu) \
334 da_monitor_reset_##name(da_get_monitor_##name(idle_task(cpu))); \
335 read_unlock(&tasklist_lock); \
336} \
337 \
338/* \
339 * da_monitor_init_##name - initialize the per-task monitor \
340 * \
341 * Try to allocate a slot in the task's vector of monitors. If there \
342 * is an available slot, use it and reset all task's monitor. \
343 */ \
344static int da_monitor_init_##name(void) \
345{ \
346 int slot; \
347 \
348 slot = rv_get_task_monitor_slot(); \
349 if (slot < 0 || slot >= RV_PER_TASK_MONITOR_INIT) \
350 return slot; \
351 \
352 task_mon_slot_##name = slot; \
353 \
354 da_monitor_reset_all_##name(); \
355 return 0; \
356} \
357 \
358/* \
359 * da_monitor_destroy_##name - return the allocated slot \
360 */ \
361static inline void da_monitor_destroy_##name(void) \
362{ \
363 if (task_mon_slot_##name == RV_PER_TASK_MONITOR_INIT) { \
364 WARN_ONCE(1, "Disabling a disabled monitor: " #name); \
365 return; \
366 } \
367 rv_put_task_monitor_slot(task_mon_slot_##name); \
368 task_mon_slot_##name = RV_PER_TASK_MONITOR_INIT; \
369 return; \
370}
371
372/*
373 * Handle event for implicit monitor: da_get_monitor_##name() will figure out
374 * the monitor.
375 */
376#define DECLARE_DA_MON_MONITOR_HANDLER_IMPLICIT(name, type) \
377 \
378static inline void __da_handle_event_##name(struct da_monitor *da_mon, \
379 enum events_##name event) \
380{ \
381 bool retval; \
382 \
383 retval = da_event_##name(da_mon, event); \
384 if (!retval) \
385 da_monitor_reset_##name(da_mon); \
386} \
387 \
388/* \
389 * da_handle_event_##name - handle an event \
390 */ \
391static inline void da_handle_event_##name(enum events_##name event) \
392{ \
393 struct da_monitor *da_mon = da_get_monitor_##name(); \
394 bool retval; \
395 \
396 retval = da_monitor_handling_event_##name(da_mon); \
397 if (!retval) \
398 return; \
399 \
400 __da_handle_event_##name(da_mon, event); \
401} \
402 \
403/* \
404 * da_handle_start_event_##name - start monitoring or handle event \
405 * \
406 * This function is used to notify the monitor that the system is returning \
407 * to the initial state, so the monitor can start monitoring in the next event. \
408 * Thus: \
409 * \
410 * If the monitor already started, handle the event. \
411 * If the monitor did not start yet, start the monitor but skip the event. \
412 */ \
413static inline bool da_handle_start_event_##name(enum events_##name event) \
414{ \
415 struct da_monitor *da_mon; \
416 \
417 if (!da_monitor_enabled_##name()) \
418 return 0; \
419 \
420 da_mon = da_get_monitor_##name(); \
421 \
422 if (unlikely(!da_monitoring_##name(da_mon))) { \
423 da_monitor_start_##name(da_mon); \
424 return 0; \
425 } \
426 \
427 __da_handle_event_##name(da_mon, event); \
428 \
429 return 1; \
430} \
431 \
432/* \
433 * da_handle_start_run_event_##name - start monitoring and handle event \
434 * \
435 * This function is used to notify the monitor that the system is in the \
436 * initial state, so the monitor can start monitoring and handling event. \
437 */ \
438static inline bool da_handle_start_run_event_##name(enum events_##name event) \
439{ \
440 struct da_monitor *da_mon; \
441 \
442 if (!da_monitor_enabled_##name()) \
443 return 0; \
444 \
445 da_mon = da_get_monitor_##name(); \
446 \
447 if (unlikely(!da_monitoring_##name(da_mon))) \
448 da_monitor_start_##name(da_mon); \
449 \
450 __da_handle_event_##name(da_mon, event); \
451 \
452 return 1; \
453}
454
455/*
456 * Handle event for per task.
457 */
458#define DECLARE_DA_MON_MONITOR_HANDLER_PER_TASK(name, type) \
459 \
460static inline void \
461__da_handle_event_##name(struct da_monitor *da_mon, struct task_struct *tsk, \
462 enum events_##name event) \
463{ \
464 bool retval; \
465 \
466 retval = da_event_##name(da_mon, tsk, event); \
467 if (!retval) \
468 da_monitor_reset_##name(da_mon); \
469} \
470 \
471/* \
472 * da_handle_event_##name - handle an event \
473 */ \
474static inline void \
475da_handle_event_##name(struct task_struct *tsk, enum events_##name event) \
476{ \
477 struct da_monitor *da_mon = da_get_monitor_##name(tsk); \
478 bool retval; \
479 \
480 retval = da_monitor_handling_event_##name(da_mon); \
481 if (!retval) \
482 return; \
483 \
484 __da_handle_event_##name(da_mon, tsk, event); \
485} \
486 \
487/* \
488 * da_handle_start_event_##name - start monitoring or handle event \
489 * \
490 * This function is used to notify the monitor that the system is returning \
491 * to the initial state, so the monitor can start monitoring in the next event. \
492 * Thus: \
493 * \
494 * If the monitor already started, handle the event. \
495 * If the monitor did not start yet, start the monitor but skip the event. \
496 */ \
497static inline bool \
498da_handle_start_event_##name(struct task_struct *tsk, enum events_##name event) \
499{ \
500 struct da_monitor *da_mon; \
501 \
502 if (!da_monitor_enabled_##name()) \
503 return 0; \
504 \
505 da_mon = da_get_monitor_##name(tsk); \
506 \
507 if (unlikely(!da_monitoring_##name(da_mon))) { \
508 da_monitor_start_##name(da_mon); \
509 return 0; \
510 } \
511 \
512 __da_handle_event_##name(da_mon, tsk, event); \
513 \
514 return 1; \
515}
516
517/*
518 * Entry point for the global monitor.
519 */
520#define DECLARE_DA_MON_GLOBAL(name, type) \
521 \
522DECLARE_AUTOMATA_HELPERS(name, type) \
523DECLARE_DA_MON_GENERIC_HELPERS(name, type) \
524DECLARE_DA_MON_MODEL_HANDLER_IMPLICIT(name, type) \
525DECLARE_DA_MON_INIT_GLOBAL(name, type) \
526DECLARE_DA_MON_MONITOR_HANDLER_IMPLICIT(name, type)
527
528/*
529 * Entry point for the per-cpu monitor.
530 */
531#define DECLARE_DA_MON_PER_CPU(name, type) \
532 \
533DECLARE_AUTOMATA_HELPERS(name, type) \
534DECLARE_DA_MON_GENERIC_HELPERS(name, type) \
535DECLARE_DA_MON_MODEL_HANDLER_IMPLICIT(name, type) \
536DECLARE_DA_MON_INIT_PER_CPU(name, type) \
537DECLARE_DA_MON_MONITOR_HANDLER_IMPLICIT(name, type)
538
539/*
540 * Entry point for the per-task monitor.
541 */
542#define DECLARE_DA_MON_PER_TASK(name, type) \
543 \
544DECLARE_AUTOMATA_HELPERS(name, type) \
545DECLARE_DA_MON_GENERIC_HELPERS(name, type) \
546DECLARE_DA_MON_MODEL_HANDLER_PER_TASK(name, type) \
547DECLARE_DA_MON_INIT_PER_TASK(name, type) \
548DECLARE_DA_MON_MONITOR_HANDLER_PER_TASK(name, type)