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