Commit | Line | Data |
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8baf2c95 MD |
1 | #define NO_RMB |
2 | #define NO_WMB | |
3 | ||
4 | #define NR_READERS 1 | |
5 | #define NR_WRITERS 1 | |
6 | ||
7 | #define NR_PROCS 2 | |
8 | ||
9 | ||
10 | #if (NR_READERS == 1) | |
11 | ||
12 | #define read_free_race (read_generation[0] == last_free_gen) | |
13 | #define read_free (free_done && data_access[0]) | |
14 | ||
15 | #elif (NR_READERS == 2) | |
16 | ||
17 | #define read_free_race (read_generation[0] == last_free_gen || read_generation[1] == last_free_gen) | |
18 | #define read_free (free_done && (data_access[0] || data_access[1])) | |
19 | ||
20 | #else | |
21 | ||
22 | #error "Too many readers" | |
23 | ||
24 | #endif | |
25 | ||
26 | #define RCU_GP_CTR_BIT (1 << 7) | |
27 | #define RCU_GP_CTR_NEST_MASK (RCU_GP_CTR_BIT - 1) | |
28 | ||
29 | #ifndef READER_NEST_LEVEL | |
30 | #define READER_NEST_LEVEL 2 | |
31 | #endif | |
32 | ||
33 | #define REMOTE_BARRIERS | |
34 | /* | |
35 | * mem.spin: Promela code to validate memory barriers with OOO memory. | |
36 | * | |
37 | * This program is free software; you can redistribute it and/or modify | |
38 | * it under the terms of the GNU General Public License as published by | |
39 | * the Free Software Foundation; either version 2 of the License, or | |
40 | * (at your option) any later version. | |
41 | * | |
42 | * This program is distributed in the hope that it will be useful, | |
43 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
44 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
45 | * GNU General Public License for more details. | |
46 | * | |
47 | * You should have received a copy of the GNU General Public License | |
48 | * along with this program; if not, write to the Free Software | |
49 | * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. | |
50 | * | |
51 | * Copyright (c) 2009 Mathieu Desnoyers | |
52 | */ | |
53 | ||
54 | /* Promela validation variables. */ | |
55 | ||
56 | /* specific defines "included" here */ | |
57 | /* DEFINES file "included" here */ | |
58 | ||
59 | #define get_pid() (_pid) | |
60 | ||
61 | /* | |
62 | * Each process have its own data in cache. Caches are randomly updated. | |
63 | * smp_wmb and smp_rmb forces cache updates (write and read), smp_mb forces | |
64 | * both. | |
65 | */ | |
66 | ||
67 | typedef per_proc_byte { | |
68 | byte val[NR_PROCS]; | |
69 | }; | |
70 | ||
71 | /* Bitfield has a maximum of 8 procs */ | |
72 | typedef per_proc_bit { | |
73 | byte bitfield; | |
74 | }; | |
75 | ||
76 | #define DECLARE_CACHED_VAR(type, x) \ | |
77 | type mem_##x; \ | |
78 | per_proc_##type cached_##x; \ | |
79 | per_proc_bit cache_dirty_##x; | |
80 | ||
81 | #define INIT_CACHED_VAR(x, v, j) \ | |
82 | mem_##x = v; \ | |
83 | cache_dirty_##x.bitfield = 0; \ | |
84 | j = 0; \ | |
85 | do \ | |
86 | :: j < NR_PROCS -> \ | |
87 | cached_##x.val[j] = v; \ | |
88 | j++ \ | |
89 | :: j >= NR_PROCS -> break \ | |
90 | od; | |
91 | ||
92 | #define IS_CACHE_DIRTY(x, id) (cache_dirty_##x.bitfield & (1 << id)) | |
93 | ||
94 | #define READ_CACHED_VAR(x) (cached_##x.val[get_pid()]) | |
95 | ||
96 | #define WRITE_CACHED_VAR(x, v) \ | |
97 | atomic { \ | |
98 | cached_##x.val[get_pid()] = v; \ | |
99 | cache_dirty_##x.bitfield = \ | |
100 | cache_dirty_##x.bitfield | (1 << get_pid()); \ | |
101 | } | |
102 | ||
103 | #define CACHE_WRITE_TO_MEM(x, id) \ | |
104 | if \ | |
105 | :: IS_CACHE_DIRTY(x, id) -> \ | |
106 | mem_##x = cached_##x.val[id]; \ | |
107 | cache_dirty_##x.bitfield = \ | |
108 | cache_dirty_##x.bitfield & (~(1 << id)); \ | |
109 | :: else -> \ | |
110 | skip \ | |
111 | fi; | |
112 | ||
113 | #define CACHE_READ_FROM_MEM(x, id) \ | |
114 | if \ | |
115 | :: !IS_CACHE_DIRTY(x, id) -> \ | |
116 | cached_##x.val[id] = mem_##x;\ | |
117 | :: else -> \ | |
118 | skip \ | |
119 | fi; | |
120 | ||
121 | /* | |
122 | * May update other caches if cache is dirty, or not. | |
123 | */ | |
124 | #define RANDOM_CACHE_WRITE_TO_MEM(x, id)\ | |
125 | if \ | |
126 | :: 1 -> CACHE_WRITE_TO_MEM(x, id); \ | |
127 | :: 1 -> skip \ | |
128 | fi; | |
129 | ||
130 | #define RANDOM_CACHE_READ_FROM_MEM(x, id)\ | |
131 | if \ | |
132 | :: 1 -> CACHE_READ_FROM_MEM(x, id); \ | |
133 | :: 1 -> skip \ | |
134 | fi; | |
135 | ||
136 | /* | |
137 | * Remote barriers tests the scheme where a signal (or IPI) is sent to all | |
138 | * reader threads to promote their compiler barrier to a smp_mb(). | |
139 | */ | |
140 | #ifdef REMOTE_BARRIERS | |
141 | ||
142 | inline smp_rmb_pid(i, j) | |
143 | { | |
144 | atomic { | |
145 | CACHE_READ_FROM_MEM(urcu_gp_ctr, i); | |
146 | j = 0; | |
147 | do | |
148 | :: j < NR_READERS -> | |
149 | CACHE_READ_FROM_MEM(urcu_active_readers[j], i); | |
150 | j++ | |
151 | :: j >= NR_READERS -> break | |
152 | od; | |
153 | CACHE_READ_FROM_MEM(generation_ptr, i); | |
154 | } | |
155 | } | |
156 | ||
157 | inline smp_wmb_pid(i, j) | |
158 | { | |
159 | atomic { | |
160 | CACHE_WRITE_TO_MEM(urcu_gp_ctr, i); | |
161 | j = 0; | |
162 | do | |
163 | :: j < NR_READERS -> | |
164 | CACHE_WRITE_TO_MEM(urcu_active_readers[j], i); | |
165 | j++ | |
166 | :: j >= NR_READERS -> break | |
167 | od; | |
168 | CACHE_WRITE_TO_MEM(generation_ptr, i); | |
169 | } | |
170 | } | |
171 | ||
172 | inline smp_mb_pid(i, j) | |
173 | { | |
174 | atomic { | |
175 | #ifndef NO_WMB | |
176 | smp_wmb_pid(i, j); | |
177 | #endif | |
178 | #ifndef NO_RMB | |
179 | smp_rmb_pid(i, j); | |
180 | #endif | |
181 | #ifdef NO_WMB | |
182 | #ifdef NO_RMB | |
183 | ooo_mem(j); | |
184 | #endif | |
185 | #endif | |
186 | } | |
187 | } | |
188 | ||
189 | /* | |
190 | * Readers do a simple barrier(), writers are doing a smp_mb() _and_ sending a | |
191 | * signal or IPI to have all readers execute a smp_mb. | |
192 | * We are not modeling the whole rendez-vous between readers and writers here, | |
193 | * we just let the writer update each reader's caches remotely. | |
194 | */ | |
195 | inline smp_mb(i, j) | |
196 | { | |
197 | if | |
198 | :: get_pid() >= NR_READERS -> | |
199 | smp_mb_pid(get_pid(), j); | |
200 | i = 0; | |
201 | do | |
202 | :: i < NR_READERS -> | |
203 | smp_mb_pid(i, j); | |
204 | i++; | |
205 | :: i >= NR_READERS -> break | |
206 | od; | |
207 | smp_mb_pid(get_pid(), j); | |
208 | :: else -> skip; | |
209 | fi; | |
210 | } | |
211 | ||
212 | #else | |
213 | ||
214 | inline smp_rmb(i, j) | |
215 | { | |
216 | atomic { | |
217 | CACHE_READ_FROM_MEM(urcu_gp_ctr, get_pid()); | |
218 | i = 0; | |
219 | do | |
220 | :: i < NR_READERS -> | |
221 | CACHE_READ_FROM_MEM(urcu_active_readers[i], get_pid()); | |
222 | i++ | |
223 | :: i >= NR_READERS -> break | |
224 | od; | |
225 | CACHE_READ_FROM_MEM(generation_ptr, get_pid()); | |
226 | } | |
227 | } | |
228 | ||
229 | inline smp_wmb(i, j) | |
230 | { | |
231 | atomic { | |
232 | CACHE_WRITE_TO_MEM(urcu_gp_ctr, get_pid()); | |
233 | i = 0; | |
234 | do | |
235 | :: i < NR_READERS -> | |
236 | CACHE_WRITE_TO_MEM(urcu_active_readers[i], get_pid()); | |
237 | i++ | |
238 | :: i >= NR_READERS -> break | |
239 | od; | |
240 | CACHE_WRITE_TO_MEM(generation_ptr, get_pid()); | |
241 | } | |
242 | } | |
243 | ||
244 | inline smp_mb(i, j) | |
245 | { | |
246 | atomic { | |
247 | #ifndef NO_WMB | |
248 | smp_wmb(i, j); | |
249 | #endif | |
250 | #ifndef NO_RMB | |
251 | smp_rmb(i, j); | |
252 | #endif | |
253 | #ifdef NO_WMB | |
254 | #ifdef NO_RMB | |
255 | ooo_mem(i); | |
256 | #endif | |
257 | #endif | |
258 | } | |
259 | } | |
260 | ||
261 | #endif | |
262 | ||
263 | /* Keep in sync manually with smp_rmb, wmp_wmb, ooo_mem and init() */ | |
264 | DECLARE_CACHED_VAR(byte, urcu_gp_ctr); | |
265 | /* Note ! currently only two readers */ | |
266 | DECLARE_CACHED_VAR(byte, urcu_active_readers[NR_READERS]); | |
267 | /* pointer generation */ | |
268 | DECLARE_CACHED_VAR(byte, generation_ptr); | |
269 | ||
270 | byte last_free_gen = 0; | |
271 | bit free_done = 0; | |
272 | byte read_generation[NR_READERS]; | |
273 | bit data_access[NR_READERS]; | |
274 | ||
275 | bit write_lock = 0; | |
276 | ||
277 | bit init_done = 0; | |
278 | ||
279 | inline wait_init_done() | |
280 | { | |
281 | do | |
282 | :: init_done == 0 -> skip; | |
283 | :: else -> break; | |
284 | od; | |
285 | } | |
286 | ||
287 | inline ooo_mem(i) | |
288 | { | |
289 | atomic { | |
290 | RANDOM_CACHE_WRITE_TO_MEM(urcu_gp_ctr, get_pid()); | |
291 | i = 0; | |
292 | do | |
293 | :: i < NR_READERS -> | |
294 | RANDOM_CACHE_WRITE_TO_MEM(urcu_active_readers[i], | |
295 | get_pid()); | |
296 | i++ | |
297 | :: i >= NR_READERS -> break | |
298 | od; | |
299 | RANDOM_CACHE_WRITE_TO_MEM(generation_ptr, get_pid()); | |
300 | RANDOM_CACHE_READ_FROM_MEM(urcu_gp_ctr, get_pid()); | |
301 | i = 0; | |
302 | do | |
303 | :: i < NR_READERS -> | |
304 | RANDOM_CACHE_READ_FROM_MEM(urcu_active_readers[i], | |
305 | get_pid()); | |
306 | i++ | |
307 | :: i >= NR_READERS -> break | |
308 | od; | |
309 | RANDOM_CACHE_READ_FROM_MEM(generation_ptr, get_pid()); | |
310 | } | |
311 | } | |
312 | ||
313 | #define get_readerid() (get_pid()) | |
314 | #define get_writerid() (get_readerid() + NR_READERS) | |
315 | ||
316 | inline wait_for_reader(tmp, tmp2, i, j) | |
317 | { | |
318 | do | |
319 | :: 1 -> | |
320 | tmp2 = READ_CACHED_VAR(urcu_active_readers[tmp]); | |
321 | ooo_mem(i); | |
322 | if | |
323 | :: (tmp2 & RCU_GP_CTR_NEST_MASK) | |
324 | && ((tmp2 ^ READ_CACHED_VAR(urcu_gp_ctr)) | |
325 | & RCU_GP_CTR_BIT) -> | |
326 | #ifndef GEN_ERROR_WRITER_PROGRESS | |
327 | smp_mb(i, j); | |
328 | #else | |
329 | ooo_mem(i); | |
330 | #endif | |
331 | :: else -> | |
332 | break; | |
333 | fi; | |
334 | od; | |
335 | } | |
336 | ||
337 | inline wait_for_quiescent_state(tmp, tmp2, i, j) | |
338 | { | |
339 | tmp = 0; | |
340 | do | |
341 | :: tmp < NR_READERS -> | |
342 | wait_for_reader(tmp, tmp2, i, j); | |
343 | if | |
344 | :: (NR_READERS > 1) && (tmp < NR_READERS - 1) | |
345 | -> ooo_mem(i); | |
346 | :: else | |
347 | -> skip; | |
348 | fi; | |
349 | tmp++ | |
350 | :: tmp >= NR_READERS -> break | |
351 | od; | |
352 | } | |
353 | ||
354 | /* Model the RCU read-side critical section. */ | |
355 | ||
356 | inline urcu_one_read(i, j, nest_i, tmp, tmp2) | |
357 | { | |
358 | nest_i = 0; | |
359 | do | |
360 | :: nest_i < READER_NEST_LEVEL -> | |
361 | ooo_mem(i); | |
362 | tmp = READ_CACHED_VAR(urcu_active_readers[get_readerid()]); | |
363 | ooo_mem(i); | |
364 | if | |
365 | :: (!(tmp & RCU_GP_CTR_NEST_MASK)) | |
366 | -> | |
367 | tmp2 = READ_CACHED_VAR(urcu_gp_ctr); | |
368 | ooo_mem(i); | |
369 | WRITE_CACHED_VAR(urcu_active_readers[get_readerid()], | |
370 | tmp2); | |
371 | :: else -> | |
372 | WRITE_CACHED_VAR(urcu_active_readers[get_readerid()], | |
373 | tmp + 1); | |
374 | fi; | |
375 | smp_mb(i, j); | |
376 | nest_i++; | |
377 | :: nest_i >= READER_NEST_LEVEL -> break; | |
378 | od; | |
379 | ||
380 | ooo_mem(i); | |
381 | read_generation[get_readerid()] = READ_CACHED_VAR(generation_ptr); | |
382 | ooo_mem(i); | |
383 | data_access[get_readerid()] = 1; | |
384 | ooo_mem(i); | |
385 | data_access[get_readerid()] = 0; | |
386 | ||
387 | nest_i = 0; | |
388 | do | |
389 | :: nest_i < READER_NEST_LEVEL -> | |
390 | smp_mb(i, j); | |
391 | tmp2 = READ_CACHED_VAR(urcu_active_readers[get_readerid()]); | |
392 | ooo_mem(i); | |
393 | WRITE_CACHED_VAR(urcu_active_readers[get_readerid()], tmp2 - 1); | |
394 | nest_i++; | |
395 | :: nest_i >= READER_NEST_LEVEL -> break; | |
396 | od; | |
397 | ooo_mem(i); | |
398 | //smp_mc(i); /* added */ | |
399 | } | |
400 | ||
401 | active [NR_READERS] proctype urcu_reader() | |
402 | { | |
403 | byte i, j, nest_i; | |
404 | byte tmp, tmp2; | |
405 | ||
406 | wait_init_done(); | |
407 | ||
408 | assert(get_pid() < NR_PROCS); | |
409 | ||
410 | end_reader: | |
411 | do | |
412 | :: 1 -> | |
413 | /* | |
414 | * We do not test reader's progress here, because we are mainly | |
415 | * interested in writer's progress. The reader never blocks | |
416 | * anyway. We have to test for reader/writer's progress | |
417 | * separately, otherwise we could think the writer is doing | |
418 | * progress when it's blocked by an always progressing reader. | |
419 | */ | |
420 | #ifdef READER_PROGRESS | |
421 | /* Only test progress of one random reader. They are all the | |
422 | * same. */ | |
423 | atomic { | |
424 | if | |
425 | :: get_readerid() == 0 -> | |
426 | progress_reader: | |
427 | skip; | |
428 | :: else -> | |
429 | skip; | |
430 | fi; | |
431 | } | |
432 | #endif | |
433 | urcu_one_read(i, j, nest_i, tmp, tmp2); | |
434 | od; | |
435 | } | |
436 | ||
437 | /* Model the RCU update process. */ | |
438 | ||
439 | active proctype urcu_writer() | |
440 | { | |
441 | byte i, j; | |
442 | byte tmp, tmp2; | |
443 | byte old_gen; | |
444 | ||
445 | wait_init_done(); | |
446 | ||
447 | assert(get_pid() < NR_PROCS); | |
448 | ||
449 | do | |
450 | :: (READ_CACHED_VAR(generation_ptr) < 5) -> | |
451 | #ifdef WRITER_PROGRESS | |
452 | progress_writer1: | |
453 | #endif | |
454 | ooo_mem(i); | |
455 | atomic { | |
456 | old_gen = READ_CACHED_VAR(generation_ptr); | |
457 | WRITE_CACHED_VAR(generation_ptr, old_gen + 1); | |
458 | } | |
459 | ooo_mem(i); | |
460 | ||
461 | do | |
462 | :: 1 -> | |
463 | atomic { | |
464 | if | |
465 | :: write_lock == 0 -> | |
466 | write_lock = 1; | |
467 | break; | |
468 | :: else -> | |
469 | skip; | |
470 | fi; | |
471 | } | |
472 | od; | |
473 | smp_mb(i, j); | |
474 | tmp = READ_CACHED_VAR(urcu_gp_ctr); | |
475 | ooo_mem(i); | |
476 | WRITE_CACHED_VAR(urcu_gp_ctr, tmp ^ RCU_GP_CTR_BIT); | |
477 | ooo_mem(i); | |
478 | //smp_mc(i); | |
479 | wait_for_quiescent_state(tmp, tmp2, i, j); | |
480 | //smp_mc(i); | |
481 | #ifndef SINGLE_FLIP | |
482 | ooo_mem(i); | |
483 | tmp = READ_CACHED_VAR(urcu_gp_ctr); | |
484 | ooo_mem(i); | |
485 | WRITE_CACHED_VAR(urcu_gp_ctr, tmp ^ RCU_GP_CTR_BIT); | |
486 | //smp_mc(i); | |
487 | ooo_mem(i); | |
488 | wait_for_quiescent_state(tmp, tmp2, i, j); | |
489 | #endif | |
490 | smp_mb(i, j); | |
491 | write_lock = 0; | |
492 | /* free-up step, e.g., kfree(). */ | |
493 | atomic { | |
494 | last_free_gen = old_gen; | |
495 | free_done = 1; | |
496 | } | |
497 | :: else -> break; | |
498 | od; | |
499 | /* | |
500 | * Given the reader loops infinitely, let the writer also busy-loop | |
501 | * with progress here so, with weak fairness, we can test the | |
502 | * writer's progress. | |
503 | */ | |
504 | end_writer: | |
505 | do | |
506 | :: 1 -> | |
507 | #ifdef WRITER_PROGRESS | |
508 | progress_writer2: | |
509 | #endif | |
510 | skip; | |
511 | od; | |
512 | } | |
513 | ||
514 | /* Leave after the readers and writers so the pid count is ok. */ | |
515 | init { | |
516 | byte i, j; | |
517 | ||
518 | atomic { | |
519 | INIT_CACHED_VAR(urcu_gp_ctr, 1, j); | |
520 | INIT_CACHED_VAR(generation_ptr, 0, j); | |
521 | ||
522 | i = 0; | |
523 | do | |
524 | :: i < NR_READERS -> | |
525 | INIT_CACHED_VAR(urcu_active_readers[i], 0, j); | |
526 | read_generation[i] = 1; | |
527 | data_access[i] = 0; | |
528 | i++; | |
529 | :: i >= NR_READERS -> break | |
530 | od; | |
531 | init_done = 1; | |
532 | } | |
533 | } |