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60a1db9d MD |
1 | /* |
2 | * mem.spin: Promela code to validate memory barriers with OOO memory. | |
3 | * | |
4 | * This program is free software; you can redistribute it and/or modify | |
5 | * it under the terms of the GNU General Public License as published by | |
6 | * the Free Software Foundation; either version 2 of the License, or | |
7 | * (at your option) any later version. | |
8 | * | |
9 | * This program is distributed in the hope that it will be useful, | |
10 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
11 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
12 | * GNU General Public License for more details. | |
13 | * | |
14 | * You should have received a copy of the GNU General Public License | |
15 | * along with this program; if not, write to the Free Software | |
16 | * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. | |
17 | * | |
18 | * Copyright (c) 2009 Mathieu Desnoyers | |
19 | */ | |
20 | ||
21 | /* Promela validation variables. */ | |
22 | ||
23 | #define NR_READERS 1 | |
89674313 | 24 | #define NR_WRITERS 1 |
60a1db9d | 25 | |
89674313 | 26 | #define NR_PROCS 2 |
60a1db9d MD |
27 | |
28 | #define get_pid() (_pid) | |
29 | ||
30 | /* | |
31 | * Each process have its own data in cache. Caches are randomly updated. | |
32 | * smp_wmb and smp_rmb forces cache updates (write and read), wmb_mb forces | |
33 | * both. | |
34 | */ | |
35 | ||
36 | #define DECLARE_CACHED_VAR(type, x, v) \ | |
37 | type mem_##x = v; \ | |
38 | type cached_##x[NR_PROCS] = v; \ | |
39 | bit cache_dirty_##x[NR_PROCS] = 0 | |
40 | ||
41 | #define IS_CACHE_DIRTY(x, id) (cache_dirty_##x[id]) | |
42 | ||
43 | #define READ_CACHED_VAR(x) (cached_##x[get_pid()]) | |
44 | ||
45 | #define WRITE_CACHED_VAR(x, v) \ | |
46 | atomic { \ | |
47 | cached_##x[get_pid()] = v; \ | |
48 | cache_dirty_##x[get_pid()] = 1; \ | |
49 | } | |
50 | ||
51 | #define CACHE_WRITE_TO_MEM(x, id) \ | |
52 | if \ | |
53 | :: IS_CACHE_DIRTY(x, id) -> \ | |
54 | mem_##x = cached_##x[id]; \ | |
55 | cache_dirty_##x[id] = 0; \ | |
56 | :: else -> \ | |
57 | skip \ | |
58 | fi; | |
59 | ||
60 | #define CACHE_READ_FROM_MEM(x, id) \ | |
61 | if \ | |
62 | :: !IS_CACHE_DIRTY(x, id) -> \ | |
63 | cached_##x[id] = mem_##x;\ | |
64 | :: else -> \ | |
65 | skip \ | |
66 | fi; | |
67 | ||
68 | /* | |
69 | * May update other caches if cache is dirty, or not. | |
70 | */ | |
71 | #define RANDOM_CACHE_WRITE_TO_MEM(x, id)\ | |
72 | if \ | |
73 | :: 1 -> CACHE_WRITE_TO_MEM(x, id); \ | |
74 | :: 1 -> skip \ | |
75 | fi; | |
76 | ||
77 | #define RANDOM_CACHE_READ_FROM_MEM(x, id)\ | |
78 | if \ | |
79 | :: 1 -> CACHE_READ_FROM_MEM(x, id); \ | |
80 | :: 1 -> skip \ | |
81 | fi; | |
82 | ||
83 | inline smp_rmb(i) | |
84 | { | |
85 | atomic { | |
86 | CACHE_READ_FROM_MEM(urcu_gp_ctr, get_pid()); | |
87 | CACHE_READ_FROM_MEM(urcu_active_readers_one, get_pid()); | |
88 | CACHE_READ_FROM_MEM(generation_ptr, get_pid()); | |
89 | } | |
90 | } | |
91 | ||
92 | inline smp_wmb(i) | |
93 | { | |
94 | atomic { | |
95 | CACHE_WRITE_TO_MEM(urcu_gp_ctr, get_pid()); | |
96 | CACHE_WRITE_TO_MEM(urcu_active_readers_one, get_pid()); | |
97 | CACHE_WRITE_TO_MEM(generation_ptr, get_pid()); | |
98 | } | |
99 | } | |
100 | ||
101 | inline smp_mb(i) | |
102 | { | |
103 | atomic { | |
104 | #ifndef NO_WMB | |
105 | smp_wmb(i); | |
106 | #endif | |
107 | #ifndef NO_RMB | |
108 | smp_rmb(i); | |
109 | #endif | |
110 | skip; | |
111 | } | |
112 | } | |
113 | ||
114 | /* Keep in sync manually with smp_rmb, wmp_wmb and ooo_mem */ | |
115 | DECLARE_CACHED_VAR(byte, urcu_gp_ctr, 1); | |
116 | /* Note ! currently only one reader */ | |
117 | DECLARE_CACHED_VAR(byte, urcu_active_readers_one, 0); | |
118 | /* pointer generation */ | |
119 | DECLARE_CACHED_VAR(byte, generation_ptr, 0); | |
120 | ||
121 | byte last_free_gen = 0; | |
122 | bit free_done = 0; | |
123 | byte read_generation = 1; | |
124 | bit data_access = 0; | |
125 | ||
2ba2a48d MD |
126 | bit write_lock = 0; |
127 | ||
60a1db9d MD |
128 | inline ooo_mem(i) |
129 | { | |
130 | atomic { | |
131 | RANDOM_CACHE_WRITE_TO_MEM(urcu_gp_ctr, get_pid()); | |
132 | RANDOM_CACHE_WRITE_TO_MEM(urcu_active_readers_one, | |
133 | get_pid()); | |
134 | RANDOM_CACHE_WRITE_TO_MEM(generation_ptr, get_pid()); | |
135 | RANDOM_CACHE_READ_FROM_MEM(urcu_gp_ctr, get_pid()); | |
136 | RANDOM_CACHE_READ_FROM_MEM(urcu_active_readers_one, | |
137 | get_pid()); | |
138 | RANDOM_CACHE_READ_FROM_MEM(generation_ptr, get_pid()); | |
139 | } | |
140 | } | |
141 | ||
142 | #define get_readerid() (get_pid()) | |
143 | #define get_writerid() (get_readerid() + NR_READERS) | |
144 | ||
145 | inline wait_for_reader(tmp, id, i) | |
146 | { | |
60a1db9d | 147 | do |
89674313 MD |
148 | :: 1 -> |
149 | ooo_mem(i); | |
150 | tmp = READ_CACHED_VAR(urcu_active_readers_one); | |
151 | if | |
152 | :: (tmp & RCU_GP_CTR_NEST_MASK) | |
153 | && ((tmp ^ READ_CACHED_VAR(urcu_gp_ctr)) | |
154 | & RCU_GP_CTR_BIT) -> | |
155 | #ifndef GEN_ERROR_WRITER_PROGRESS | |
156 | smp_mb(i); | |
157 | #else | |
60a1db9d | 158 | skip; |
89674313 MD |
159 | #endif |
160 | :: else -> | |
60a1db9d | 161 | break; |
89674313 | 162 | fi; |
60a1db9d MD |
163 | od; |
164 | } | |
165 | ||
166 | inline wait_for_quiescent_state(tmp, i, j) | |
167 | { | |
168 | i = 0; | |
169 | do | |
170 | :: i < NR_READERS -> | |
171 | wait_for_reader(tmp, i, j); | |
172 | i++ | |
173 | :: i >= NR_READERS -> break | |
174 | od; | |
175 | } | |
176 | ||
177 | /* Model the RCU read-side critical section. */ | |
178 | ||
179 | active [NR_READERS] proctype urcu_reader() | |
180 | { | |
06d6106d | 181 | byte i, nest_i; |
60a1db9d MD |
182 | byte tmp, tmp2; |
183 | ||
184 | assert(get_pid() < NR_PROCS); | |
185 | ||
89674313 MD |
186 | end_reader: |
187 | do | |
188 | :: 1 -> | |
189 | /* | |
190 | * We do not test reader's progress here, because we are mainly | |
191 | * interested in writer's progress. The reader never blocks | |
192 | * anyway. We have to test for reader/writer's progress | |
193 | * separately, otherwise we could think the writer is doing | |
194 | * progress when it's blocked by an always progressing reader. | |
195 | */ | |
196 | #ifdef READER_PROGRESS | |
197 | progress_reader: | |
198 | #endif | |
06d6106d MD |
199 | nest_i = 0; |
200 | do | |
201 | :: nest_i < READER_NEST_LEVEL -> | |
89674313 | 202 | ooo_mem(i); |
06d6106d MD |
203 | tmp = READ_CACHED_VAR(urcu_active_readers_one); |
204 | ooo_mem(i); | |
205 | if | |
206 | :: (!(tmp & RCU_GP_CTR_NEST_MASK)) | |
207 | -> | |
208 | tmp2 = READ_CACHED_VAR(urcu_gp_ctr); | |
209 | ooo_mem(i); | |
210 | WRITE_CACHED_VAR(urcu_active_readers_one, tmp2); | |
211 | :: else -> | |
212 | WRITE_CACHED_VAR(urcu_active_readers_one, tmp + 1); | |
213 | fi; | |
214 | ooo_mem(i); | |
215 | smp_mb(i); | |
216 | nest_i++; | |
217 | :: nest_i >= READER_NEST_LEVEL -> break; | |
218 | od; | |
219 | ||
89674313 | 220 | ooo_mem(i); |
89674313 MD |
221 | read_generation = READ_CACHED_VAR(generation_ptr); |
222 | ooo_mem(i); | |
223 | data_access = 1; | |
224 | ooo_mem(i); | |
225 | data_access = 0; | |
06d6106d MD |
226 | |
227 | nest_i = 0; | |
228 | do | |
229 | :: nest_i < READER_NEST_LEVEL -> | |
230 | ooo_mem(i); | |
231 | smp_mb(i); | |
232 | ooo_mem(i); | |
233 | tmp2 = READ_CACHED_VAR(urcu_active_readers_one); | |
234 | ooo_mem(i); | |
235 | WRITE_CACHED_VAR(urcu_active_readers_one, tmp2 - 1); | |
236 | nest_i++; | |
237 | :: nest_i >= READER_NEST_LEVEL -> break; | |
238 | od; | |
89674313 | 239 | ooo_mem(i); |
89674313 MD |
240 | //smp_mc(i); /* added */ |
241 | od; | |
60a1db9d MD |
242 | } |
243 | ||
244 | ||
245 | /* Model the RCU update process. */ | |
246 | ||
247 | active [NR_WRITERS] proctype urcu_writer() | |
248 | { | |
249 | byte i, j; | |
250 | byte tmp; | |
251 | byte old_gen; | |
252 | ||
253 | assert(get_pid() < NR_PROCS); | |
254 | ||
2ba2a48d | 255 | do |
89674313 MD |
256 | :: (READ_CACHED_VAR(generation_ptr) < 5) -> |
257 | #ifdef WRITER_PROGRESS | |
258 | progress_writer1: | |
259 | #endif | |
260 | ooo_mem(i); | |
710b09b7 | 261 | atomic { |
89674313 MD |
262 | old_gen = READ_CACHED_VAR(generation_ptr); |
263 | WRITE_CACHED_VAR(generation_ptr, old_gen + 1); | |
710b09b7 | 264 | } |
89674313 MD |
265 | ooo_mem(i); |
266 | ||
267 | do | |
268 | :: 1 -> | |
269 | atomic { | |
270 | if | |
271 | :: write_lock == 0 -> | |
272 | write_lock = 1; | |
273 | break; | |
274 | :: else -> | |
275 | skip; | |
276 | fi; | |
277 | } | |
278 | od; | |
279 | smp_mb(i); | |
280 | ooo_mem(i); | |
281 | tmp = READ_CACHED_VAR(urcu_gp_ctr); | |
282 | ooo_mem(i); | |
283 | WRITE_CACHED_VAR(urcu_gp_ctr, tmp ^ RCU_GP_CTR_BIT); | |
284 | ooo_mem(i); | |
285 | //smp_mc(i); | |
286 | wait_for_quiescent_state(tmp, i, j); | |
287 | //smp_mc(i); | |
288 | #ifndef SINGLE_FLIP | |
289 | ooo_mem(i); | |
290 | tmp = READ_CACHED_VAR(urcu_gp_ctr); | |
291 | ooo_mem(i); | |
292 | WRITE_CACHED_VAR(urcu_gp_ctr, tmp ^ RCU_GP_CTR_BIT); | |
293 | //smp_mc(i); | |
294 | ooo_mem(i); | |
295 | wait_for_quiescent_state(tmp, i, j); | |
296 | #endif | |
297 | ooo_mem(i); | |
298 | smp_mb(i); | |
299 | ooo_mem(i); | |
300 | write_lock = 0; | |
301 | /* free-up step, e.g., kfree(). */ | |
302 | atomic { | |
303 | last_free_gen = old_gen; | |
304 | free_done = 1; | |
305 | } | |
306 | :: else -> break; | |
2ba2a48d | 307 | od; |
89674313 MD |
308 | /* |
309 | * Given the reader loops infinitely, let the writer also busy-loop | |
310 | * with progress here so, with weak fairness, we can test the | |
311 | * writer's progress. | |
312 | */ | |
313 | end_writer: | |
314 | do | |
315 | :: 1 -> | |
316 | #ifdef WRITER_PROGRESS | |
317 | progress_writer2: | |
2ba2a48d | 318 | #endif |
89674313 MD |
319 | skip; |
320 | od; | |
60a1db9d | 321 | } |