Commit | Line | Data |
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06e8b2a8 MD |
1 | #define NO_WMB |
2 | ||
3 | #define NR_READERS 1 | |
4 | #define NR_WRITERS 1 | |
5 | ||
6 | #define NR_PROCS 2 | |
7 | ||
8 | ||
9 | #if (NR_READERS == 1) | |
10 | ||
11 | #define read_free_race (read_generation[0] == last_free_gen) | |
12 | #define read_free (free_done && data_access[0]) | |
13 | ||
14 | #elif (NR_READERS == 2) | |
15 | ||
16 | #define read_free_race (read_generation[0] == last_free_gen || read_generation[1] == last_free_gen) | |
17 | #define read_free (free_done && (data_access[0] || data_access[1])) | |
18 | ||
19 | #else | |
20 | ||
21 | #error "Too many readers" | |
22 | ||
23 | #endif | |
24 | ||
25 | #define RCU_GP_CTR_BIT (1 << 7) | |
26 | #define RCU_GP_CTR_NEST_MASK (RCU_GP_CTR_BIT - 1) | |
27 | ||
28 | #ifndef READER_NEST_LEVEL | |
29 | #define READER_NEST_LEVEL 2 | |
30 | #endif | |
31 | ||
32 | #define REMOTE_BARRIERS | |
33 | /* | |
34 | * mem.spin: Promela code to validate memory barriers with OOO memory. | |
35 | * | |
36 | * This program is free software; you can redistribute it and/or modify | |
37 | * it under the terms of the GNU General Public License as published by | |
38 | * the Free Software Foundation; either version 2 of the License, or | |
39 | * (at your option) any later version. | |
40 | * | |
41 | * This program is distributed in the hope that it will be useful, | |
42 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
43 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
44 | * GNU General Public License for more details. | |
45 | * | |
46 | * You should have received a copy of the GNU General Public License | |
47 | * along with this program; if not, write to the Free Software | |
48 | * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. | |
49 | * | |
50 | * Copyright (c) 2009 Mathieu Desnoyers | |
51 | */ | |
52 | ||
53 | /* Promela validation variables. */ | |
54 | ||
55 | /* specific defines "included" here */ | |
56 | /* DEFINES file "included" here */ | |
57 | ||
58 | #define get_pid() (_pid) | |
59 | ||
60 | /* | |
61 | * Each process have its own data in cache. Caches are randomly updated. | |
62 | * smp_wmb and smp_rmb forces cache updates (write and read), smp_mb forces | |
63 | * both. | |
64 | */ | |
65 | ||
66 | typedef per_proc_byte { | |
67 | byte val[NR_PROCS]; | |
68 | }; | |
69 | ||
70 | /* Bitfield has a maximum of 8 procs */ | |
71 | typedef per_proc_bit { | |
72 | byte bitfield; | |
73 | }; | |
74 | ||
75 | #define DECLARE_CACHED_VAR(type, x) \ | |
76 | type mem_##x; \ | |
77 | per_proc_##type cached_##x; \ | |
78 | per_proc_bit cache_dirty_##x; | |
79 | ||
80 | #define INIT_CACHED_VAR(x, v, j) \ | |
81 | mem_##x = v; \ | |
82 | cache_dirty_##x.bitfield = 0; \ | |
83 | j = 0; \ | |
84 | do \ | |
85 | :: j < NR_PROCS -> \ | |
86 | cached_##x.val[j] = v; \ | |
87 | j++ \ | |
88 | :: j >= NR_PROCS -> break \ | |
89 | od; | |
90 | ||
91 | #define IS_CACHE_DIRTY(x, id) (cache_dirty_##x.bitfield & (1 << id)) | |
92 | ||
93 | #define READ_CACHED_VAR(x) (cached_##x.val[get_pid()]) | |
94 | ||
95 | #define WRITE_CACHED_VAR(x, v) \ | |
96 | atomic { \ | |
97 | cached_##x.val[get_pid()] = v; \ | |
98 | cache_dirty_##x.bitfield = \ | |
99 | cache_dirty_##x.bitfield | (1 << get_pid()); \ | |
100 | } | |
101 | ||
102 | #define CACHE_WRITE_TO_MEM(x, id) \ | |
103 | if \ | |
104 | :: IS_CACHE_DIRTY(x, id) -> \ | |
105 | mem_##x = cached_##x.val[id]; \ | |
106 | cache_dirty_##x.bitfield = \ | |
107 | cache_dirty_##x.bitfield & (~(1 << id)); \ | |
108 | :: else -> \ | |
109 | skip \ | |
110 | fi; | |
111 | ||
112 | #define CACHE_READ_FROM_MEM(x, id) \ | |
113 | if \ | |
114 | :: !IS_CACHE_DIRTY(x, id) -> \ | |
115 | cached_##x.val[id] = mem_##x;\ | |
116 | :: else -> \ | |
117 | skip \ | |
118 | fi; | |
119 | ||
120 | /* | |
121 | * May update other caches if cache is dirty, or not. | |
122 | */ | |
123 | #define RANDOM_CACHE_WRITE_TO_MEM(x, id)\ | |
124 | if \ | |
125 | :: 1 -> CACHE_WRITE_TO_MEM(x, id); \ | |
126 | :: 1 -> skip \ | |
127 | fi; | |
128 | ||
129 | #define RANDOM_CACHE_READ_FROM_MEM(x, id)\ | |
130 | if \ | |
131 | :: 1 -> CACHE_READ_FROM_MEM(x, id); \ | |
132 | :: 1 -> skip \ | |
133 | fi; | |
134 | ||
135 | /* | |
136 | * Remote barriers tests the scheme where a signal (or IPI) is sent to all | |
137 | * reader threads to promote their compiler barrier to a smp_mb(). | |
138 | */ | |
139 | #ifdef REMOTE_BARRIERS | |
140 | ||
141 | inline smp_rmb_pid(i, j) | |
142 | { | |
143 | atomic { | |
144 | CACHE_READ_FROM_MEM(urcu_gp_ctr, i); | |
145 | j = 0; | |
146 | do | |
147 | :: j < NR_READERS -> | |
148 | CACHE_READ_FROM_MEM(urcu_active_readers[j], i); | |
149 | j++ | |
150 | :: j >= NR_READERS -> break | |
151 | od; | |
152 | CACHE_READ_FROM_MEM(generation_ptr, i); | |
153 | } | |
154 | } | |
155 | ||
156 | inline smp_wmb_pid(i, j) | |
157 | { | |
158 | atomic { | |
159 | CACHE_WRITE_TO_MEM(urcu_gp_ctr, i); | |
160 | j = 0; | |
161 | do | |
162 | :: j < NR_READERS -> | |
163 | CACHE_WRITE_TO_MEM(urcu_active_readers[j], i); | |
164 | j++ | |
165 | :: j >= NR_READERS -> break | |
166 | od; | |
167 | CACHE_WRITE_TO_MEM(generation_ptr, i); | |
168 | } | |
169 | } | |
170 | ||
171 | inline smp_mb_pid(i, j) | |
172 | { | |
173 | atomic { | |
174 | #ifndef NO_WMB | |
175 | smp_wmb_pid(i, j); | |
176 | #endif | |
177 | #ifndef NO_RMB | |
178 | smp_rmb_pid(i, j); | |
179 | #endif | |
180 | #ifdef NO_WMB | |
181 | #ifdef NO_RMB | |
182 | ooo_mem(i); | |
183 | #endif | |
184 | #endif | |
185 | } | |
186 | } | |
187 | ||
188 | /* | |
189 | * Readers do a simple barrier(), writers are doing a smp_mb() _and_ sending a | |
190 | * signal or IPI to have all readers execute a smp_mb. | |
191 | * We are not modeling the whole rendez-vous between readers and writers here, | |
192 | * we just let the writer update each reader's caches remotely. | |
193 | */ | |
194 | inline smp_mb(i, j) | |
195 | { | |
196 | if | |
197 | :: get_pid() >= NR_READERS -> | |
198 | smp_mb_pid(get_pid(), j); | |
199 | i = 0; | |
200 | do | |
201 | :: i < NR_READERS -> | |
202 | smp_mb_pid(i, j); | |
203 | i++; | |
204 | :: i >= NR_READERS -> break | |
205 | od; | |
206 | smp_mb_pid(get_pid(), j); | |
207 | :: else -> skip; | |
208 | fi; | |
209 | } | |
210 | ||
211 | #else | |
212 | ||
213 | inline smp_rmb(i, j) | |
214 | { | |
215 | atomic { | |
216 | CACHE_READ_FROM_MEM(urcu_gp_ctr, get_pid()); | |
217 | i = 0; | |
218 | do | |
219 | :: i < NR_READERS -> | |
220 | CACHE_READ_FROM_MEM(urcu_active_readers[i], get_pid()); | |
221 | i++ | |
222 | :: i >= NR_READERS -> break | |
223 | od; | |
224 | CACHE_READ_FROM_MEM(generation_ptr, get_pid()); | |
225 | } | |
226 | } | |
227 | ||
228 | inline smp_wmb(i, j) | |
229 | { | |
230 | atomic { | |
231 | CACHE_WRITE_TO_MEM(urcu_gp_ctr, get_pid()); | |
232 | i = 0; | |
233 | do | |
234 | :: i < NR_READERS -> | |
235 | CACHE_WRITE_TO_MEM(urcu_active_readers[i], get_pid()); | |
236 | i++ | |
237 | :: i >= NR_READERS -> break | |
238 | od; | |
239 | CACHE_WRITE_TO_MEM(generation_ptr, get_pid()); | |
240 | } | |
241 | } | |
242 | ||
243 | inline smp_mb(i, j) | |
244 | { | |
245 | atomic { | |
246 | #ifndef NO_WMB | |
247 | smp_wmb(i, j); | |
248 | #endif | |
249 | #ifndef NO_RMB | |
250 | smp_rmb(i, j); | |
251 | #endif | |
252 | #ifdef NO_WMB | |
253 | #ifdef NO_RMB | |
254 | ooo_mem(i); | |
255 | #endif | |
256 | #endif | |
257 | } | |
258 | } | |
259 | ||
260 | #endif | |
261 | ||
262 | /* Keep in sync manually with smp_rmb, wmp_wmb, ooo_mem and init() */ | |
263 | DECLARE_CACHED_VAR(byte, urcu_gp_ctr); | |
264 | /* Note ! currently only two readers */ | |
265 | DECLARE_CACHED_VAR(byte, urcu_active_readers[NR_READERS]); | |
266 | /* pointer generation */ | |
267 | DECLARE_CACHED_VAR(byte, generation_ptr); | |
268 | ||
269 | byte last_free_gen = 0; | |
270 | bit free_done = 0; | |
271 | byte read_generation[NR_READERS]; | |
272 | bit data_access[NR_READERS]; | |
273 | ||
274 | bit write_lock = 0; | |
275 | ||
276 | bit init_done = 0; | |
277 | ||
278 | inline wait_init_done() | |
279 | { | |
280 | do | |
281 | :: init_done == 0 -> skip; | |
282 | :: else -> break; | |
283 | od; | |
284 | } | |
285 | ||
286 | inline ooo_mem(i) | |
287 | { | |
288 | atomic { | |
289 | RANDOM_CACHE_WRITE_TO_MEM(urcu_gp_ctr, get_pid()); | |
290 | i = 0; | |
291 | do | |
292 | :: i < NR_READERS -> | |
293 | RANDOM_CACHE_WRITE_TO_MEM(urcu_active_readers[i], | |
294 | get_pid()); | |
295 | i++ | |
296 | :: i >= NR_READERS -> break | |
297 | od; | |
298 | RANDOM_CACHE_WRITE_TO_MEM(generation_ptr, get_pid()); | |
299 | RANDOM_CACHE_READ_FROM_MEM(urcu_gp_ctr, get_pid()); | |
300 | i = 0; | |
301 | do | |
302 | :: i < NR_READERS -> | |
303 | RANDOM_CACHE_READ_FROM_MEM(urcu_active_readers[i], | |
304 | get_pid()); | |
305 | i++ | |
306 | :: i >= NR_READERS -> break | |
307 | od; | |
308 | RANDOM_CACHE_READ_FROM_MEM(generation_ptr, get_pid()); | |
309 | } | |
310 | } | |
311 | ||
312 | #define get_readerid() (get_pid()) | |
313 | #define get_writerid() (get_readerid() + NR_READERS) | |
314 | ||
315 | inline wait_for_reader(tmp, tmp2, i, j) | |
316 | { | |
317 | do | |
318 | :: 1 -> | |
319 | tmp2 = READ_CACHED_VAR(urcu_active_readers[tmp]); | |
320 | ooo_mem(i); | |
321 | if | |
322 | :: (tmp2 & RCU_GP_CTR_NEST_MASK) | |
323 | && ((tmp2 ^ READ_CACHED_VAR(urcu_gp_ctr)) | |
324 | & RCU_GP_CTR_BIT) -> | |
325 | #ifndef GEN_ERROR_WRITER_PROGRESS | |
326 | smp_mb(i, j); | |
327 | #else | |
328 | ooo_mem(i); | |
329 | #endif | |
330 | :: else -> | |
331 | break; | |
332 | fi; | |
333 | od; | |
334 | } | |
335 | ||
336 | inline wait_for_quiescent_state(tmp, tmp2, i, j) | |
337 | { | |
338 | tmp = 0; | |
339 | do | |
340 | :: tmp < NR_READERS -> | |
341 | wait_for_reader(tmp, tmp2, i, j); | |
342 | if | |
343 | :: (NR_READERS > 1) && (tmp < NR_READERS - 1) | |
344 | -> ooo_mem(i); | |
345 | :: else | |
346 | -> skip; | |
347 | fi; | |
348 | tmp++ | |
349 | :: tmp >= NR_READERS -> break | |
350 | od; | |
351 | } | |
352 | ||
353 | /* Model the RCU read-side critical section. */ | |
354 | ||
355 | inline urcu_one_read(i, j, nest_i, tmp, tmp2) | |
356 | { | |
357 | nest_i = 0; | |
358 | do | |
359 | :: nest_i < READER_NEST_LEVEL -> | |
360 | ooo_mem(i); | |
361 | tmp = READ_CACHED_VAR(urcu_active_readers[get_readerid()]); | |
362 | ooo_mem(i); | |
363 | if | |
364 | :: (!(tmp & RCU_GP_CTR_NEST_MASK)) | |
365 | -> | |
366 | tmp2 = READ_CACHED_VAR(urcu_gp_ctr); | |
367 | ooo_mem(i); | |
368 | WRITE_CACHED_VAR(urcu_active_readers[get_readerid()], | |
369 | tmp2); | |
370 | :: else -> | |
371 | WRITE_CACHED_VAR(urcu_active_readers[get_readerid()], | |
372 | tmp + 1); | |
373 | fi; | |
374 | smp_mb(i, j); | |
375 | nest_i++; | |
376 | :: nest_i >= READER_NEST_LEVEL -> break; | |
377 | od; | |
378 | ||
379 | ooo_mem(i); | |
380 | read_generation[get_readerid()] = READ_CACHED_VAR(generation_ptr); | |
381 | ooo_mem(i); | |
382 | data_access[get_readerid()] = 1; | |
383 | ooo_mem(i); | |
384 | data_access[get_readerid()] = 0; | |
385 | ||
386 | nest_i = 0; | |
387 | do | |
388 | :: nest_i < READER_NEST_LEVEL -> | |
389 | smp_mb(i, j); | |
390 | tmp2 = READ_CACHED_VAR(urcu_active_readers[get_readerid()]); | |
391 | ooo_mem(i); | |
392 | WRITE_CACHED_VAR(urcu_active_readers[get_readerid()], tmp2 - 1); | |
393 | nest_i++; | |
394 | :: nest_i >= READER_NEST_LEVEL -> break; | |
395 | od; | |
396 | ooo_mem(i); | |
397 | //smp_mc(i); /* added */ | |
398 | } | |
399 | ||
400 | active [NR_READERS] proctype urcu_reader() | |
401 | { | |
402 | byte i, j, nest_i; | |
403 | byte tmp, tmp2; | |
404 | ||
405 | wait_init_done(); | |
406 | ||
407 | assert(get_pid() < NR_PROCS); | |
408 | ||
409 | end_reader: | |
410 | do | |
411 | :: 1 -> | |
412 | /* | |
413 | * We do not test reader's progress here, because we are mainly | |
414 | * interested in writer's progress. The reader never blocks | |
415 | * anyway. We have to test for reader/writer's progress | |
416 | * separately, otherwise we could think the writer is doing | |
417 | * progress when it's blocked by an always progressing reader. | |
418 | */ | |
419 | #ifdef READER_PROGRESS | |
420 | /* Only test progress of one random reader. They are all the | |
421 | * same. */ | |
422 | atomic { | |
423 | if | |
424 | :: get_readerid() == 0 -> | |
425 | progress_reader: | |
426 | skip; | |
427 | :: else -> | |
428 | skip; | |
429 | fi; | |
430 | } | |
431 | #endif | |
432 | urcu_one_read(i, j, nest_i, tmp, tmp2); | |
433 | od; | |
434 | } | |
435 | ||
436 | /* Model the RCU update process. */ | |
437 | ||
438 | active proctype urcu_writer() | |
439 | { | |
440 | byte i, j; | |
441 | byte tmp, tmp2; | |
442 | byte old_gen; | |
443 | ||
444 | wait_init_done(); | |
445 | ||
446 | assert(get_pid() < NR_PROCS); | |
447 | ||
448 | do | |
449 | :: (READ_CACHED_VAR(generation_ptr) < 5) -> | |
450 | #ifdef WRITER_PROGRESS | |
451 | progress_writer1: | |
452 | #endif | |
453 | ooo_mem(i); | |
454 | atomic { | |
455 | old_gen = READ_CACHED_VAR(generation_ptr); | |
456 | WRITE_CACHED_VAR(generation_ptr, old_gen + 1); | |
457 | } | |
458 | ooo_mem(i); | |
459 | ||
460 | do | |
461 | :: 1 -> | |
462 | atomic { | |
463 | if | |
464 | :: write_lock == 0 -> | |
465 | write_lock = 1; | |
466 | break; | |
467 | :: else -> | |
468 | skip; | |
469 | fi; | |
470 | } | |
471 | od; | |
472 | smp_mb(i, j); | |
473 | tmp = READ_CACHED_VAR(urcu_gp_ctr); | |
474 | ooo_mem(i); | |
475 | WRITE_CACHED_VAR(urcu_gp_ctr, tmp ^ RCU_GP_CTR_BIT); | |
476 | ooo_mem(i); | |
477 | //smp_mc(i); | |
478 | wait_for_quiescent_state(tmp, tmp2, i, j); | |
479 | //smp_mc(i); | |
480 | #ifndef SINGLE_FLIP | |
481 | ooo_mem(i); | |
482 | tmp = READ_CACHED_VAR(urcu_gp_ctr); | |
483 | ooo_mem(i); | |
484 | WRITE_CACHED_VAR(urcu_gp_ctr, tmp ^ RCU_GP_CTR_BIT); | |
485 | //smp_mc(i); | |
486 | ooo_mem(i); | |
487 | wait_for_quiescent_state(tmp, tmp2, i, j); | |
488 | #endif | |
489 | smp_mb(i, j); | |
490 | write_lock = 0; | |
491 | /* free-up step, e.g., kfree(). */ | |
492 | atomic { | |
493 | last_free_gen = old_gen; | |
494 | free_done = 1; | |
495 | } | |
496 | :: else -> break; | |
497 | od; | |
498 | /* | |
499 | * Given the reader loops infinitely, let the writer also busy-loop | |
500 | * with progress here so, with weak fairness, we can test the | |
501 | * writer's progress. | |
502 | */ | |
503 | end_writer: | |
504 | do | |
505 | :: 1 -> | |
506 | #ifdef WRITER_PROGRESS | |
507 | progress_writer2: | |
508 | #endif | |
509 | skip; | |
510 | od; | |
511 | } | |
512 | ||
513 | /* Leave after the readers and writers so the pid count is ok. */ | |
514 | init { | |
515 | byte i, j; | |
516 | ||
517 | atomic { | |
518 | INIT_CACHED_VAR(urcu_gp_ctr, 1, j); | |
519 | INIT_CACHED_VAR(generation_ptr, 0, j); | |
520 | ||
521 | i = 0; | |
522 | do | |
523 | :: i < NR_READERS -> | |
524 | INIT_CACHED_VAR(urcu_active_readers[i], 0, j); | |
525 | read_generation[i] = 1; | |
526 | data_access[i] = 0; | |
527 | i++; | |
528 | :: i >= NR_READERS -> break | |
529 | od; | |
530 | init_done = 1; | |
531 | } | |
532 | } |