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b76e5200 MD |
1 | /* |
2 | * rseq.h | |
3 | * | |
4 | * (C) Copyright 2016 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com> | |
5 | * | |
6 | * Permission is hereby granted, free of charge, to any person obtaining a copy | |
7 | * of this software and associated documentation files (the "Software"), to deal | |
8 | * in the Software without restriction, including without limitation the rights | |
9 | * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell | |
10 | * copies of the Software, and to permit persons to whom the Software is | |
11 | * furnished to do so, subject to the following conditions: | |
12 | * | |
13 | * The above copyright notice and this permission notice shall be included in | |
14 | * all copies or substantial portions of the Software. | |
15 | * | |
16 | * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR | |
17 | * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, | |
18 | * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE | |
19 | * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER | |
20 | * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, | |
21 | * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE | |
22 | * SOFTWARE. | |
23 | */ | |
24 | ||
25 | #ifndef RSEQ_H | |
26 | #define RSEQ_H | |
27 | ||
28 | #include <stdint.h> | |
29 | #include <stdbool.h> | |
30 | #include <pthread.h> | |
31 | #include <signal.h> | |
32 | #include <sched.h> | |
33 | #include <errno.h> | |
34 | #include <stdio.h> | |
35 | #include <stdlib.h> | |
36 | #include <sched.h> | |
26cc635c | 37 | #include <unistd.h> |
38bfb073 MD |
38 | #include <urcu/compiler.h> |
39 | #include <urcu/system.h> | |
40 | #include <urcu/arch.h> | |
26cc635c | 41 | #include <lttng/ringbuffer-config.h> /* for struct lttng_rseq_state */ |
b76e5200 MD |
42 | #include "linux-rseq-abi.h" |
43 | ||
44 | /* | |
45 | * Empty code injection macros, override when testing. | |
46 | * It is important to consider that the ASM injection macros need to be | |
47 | * fully reentrant (e.g. do not modify the stack). | |
48 | */ | |
49 | #ifndef RSEQ_INJECT_ASM | |
50 | #define RSEQ_INJECT_ASM(n) | |
51 | #endif | |
52 | ||
53 | #ifndef RSEQ_INJECT_C | |
54 | #define RSEQ_INJECT_C(n) | |
55 | #endif | |
56 | ||
57 | #ifndef RSEQ_INJECT_INPUT | |
58 | #define RSEQ_INJECT_INPUT | |
59 | #endif | |
60 | ||
61 | #ifndef RSEQ_INJECT_CLOBBER | |
62 | #define RSEQ_INJECT_CLOBBER | |
63 | #endif | |
64 | ||
65 | #ifndef RSEQ_INJECT_FAILED | |
66 | #define RSEQ_INJECT_FAILED | |
67 | #endif | |
68 | ||
69 | #ifndef RSEQ_FALLBACK_CNT | |
70 | #define RSEQ_FALLBACK_CNT 3 | |
71 | #endif | |
72 | ||
b76e5200 | 73 | extern __thread volatile struct rseq __rseq_abi; |
b76e5200 MD |
74 | |
75 | #if defined(__x86_64__) || defined(__i386__) | |
26cc635c MD |
76 | #include "rseq-x86.h" |
77 | #ifdef __NR_rseq | |
78 | #define ARCH_HAS_RSEQ 1 | |
79 | #endif | |
b76e5200 | 80 | #elif defined(__ARMEL__) |
26cc635c MD |
81 | #include "rseq-arm.h" |
82 | #ifdef __NR_rseq | |
83 | #define ARCH_HAS_RSEQ 1 | |
84 | #endif | |
b76e5200 | 85 | #elif defined(__PPC__) |
26cc635c MD |
86 | #include "rseq-ppc.h" |
87 | #ifdef __NR_rseq | |
88 | #define ARCH_HAS_RSEQ 1 | |
89 | #endif | |
b76e5200 MD |
90 | #else |
91 | #error unsupported target | |
92 | #endif | |
93 | ||
b76e5200 MD |
94 | /* |
95 | * Register rseq for the current thread. This needs to be called once | |
96 | * by any thread which uses restartable sequences, before they start | |
38bfb073 | 97 | * using restartable sequences. |
b76e5200 MD |
98 | */ |
99 | int rseq_register_current_thread(void); | |
100 | ||
101 | /* | |
102 | * Unregister rseq for current thread. | |
103 | */ | |
104 | int rseq_unregister_current_thread(void); | |
105 | ||
26cc635c MD |
106 | void rseq_init(void); |
107 | void rseq_destroy(void); | |
b76e5200 | 108 | |
26cc635c | 109 | static inline int32_t rseq_cpu_at_start(struct lttng_rseq_state start_value) |
b76e5200 MD |
110 | { |
111 | return start_value.cpu_id; | |
112 | } | |
113 | ||
114 | static inline int32_t rseq_current_cpu_raw(void) | |
115 | { | |
38bfb073 | 116 | return CMM_LOAD_SHARED(__rseq_abi.u.e.cpu_id); |
b76e5200 MD |
117 | } |
118 | ||
26cc635c | 119 | #ifdef ARCH_HAS_RSEQ |
b76e5200 | 120 | static inline __attribute__((always_inline)) |
26cc635c | 121 | struct lttng_rseq_state rseq_start(void) |
b76e5200 | 122 | { |
26cc635c | 123 | struct lttng_rseq_state result; |
b76e5200 MD |
124 | |
125 | result.rseqp = &__rseq_abi; | |
126 | if (has_single_copy_load_64()) { | |
127 | union rseq_cpu_event u; | |
128 | ||
38bfb073 | 129 | u.v = CMM_LOAD_SHARED(result.rseqp->u.v); |
b76e5200 MD |
130 | result.event_counter = u.e.event_counter; |
131 | result.cpu_id = u.e.cpu_id; | |
132 | } else { | |
133 | result.event_counter = | |
38bfb073 | 134 | CMM_LOAD_SHARED(result.rseqp->u.e.event_counter); |
b76e5200 MD |
135 | /* load event_counter before cpu_id. */ |
136 | RSEQ_INJECT_C(6) | |
38bfb073 | 137 | result.cpu_id = CMM_LOAD_SHARED(result.rseqp->u.e.cpu_id); |
b76e5200 MD |
138 | } |
139 | /* | |
140 | * Read event counter before lock state and cpu_id. This ensures | |
141 | * that when the state changes from RESTART to LOCK, if we have | |
142 | * some threads that have already seen the RESTART still in | |
143 | * flight, they will necessarily be preempted/signalled before a | |
144 | * thread can see the LOCK state for that same CPU. That | |
145 | * preemption/signalling will cause them to restart, so they | |
146 | * don't interfere with the lock. | |
147 | */ | |
148 | RSEQ_INJECT_C(7) | |
149 | ||
b76e5200 MD |
150 | /* |
151 | * Ensure the compiler does not re-order loads of protected | |
152 | * values before we load the event counter. | |
153 | */ | |
38bfb073 | 154 | cmm_barrier(); |
b76e5200 MD |
155 | return result; |
156 | } | |
26cc635c MD |
157 | #else |
158 | static inline __attribute__((always_inline)) | |
159 | struct lttng_rseq_state rseq_start(void) | |
160 | { | |
161 | struct lttng_rseq_state result = { | |
162 | .cpu_id = -2, | |
163 | }; | |
164 | return result; | |
165 | } | |
166 | #endif | |
b76e5200 MD |
167 | |
168 | enum rseq_finish_type { | |
169 | RSEQ_FINISH_SINGLE, | |
170 | RSEQ_FINISH_TWO, | |
171 | RSEQ_FINISH_MEMCPY, | |
172 | }; | |
173 | ||
174 | /* | |
175 | * p_spec and to_write_spec are used for a speculative write attempted | |
176 | * near the end of the restartable sequence. A rseq_finish2 may fail | |
177 | * even after this write takes place. | |
178 | * | |
179 | * p_final and to_write_final are used for the final write. If this | |
180 | * write takes place, the rseq_finish2 is guaranteed to succeed. | |
181 | */ | |
26cc635c | 182 | #ifdef ARCH_HAS_RSEQ |
b76e5200 | 183 | static inline __attribute__((always_inline)) |
38bfb073 | 184 | bool __rseq_finish(intptr_t *p_spec, intptr_t to_write_spec, |
b76e5200 MD |
185 | void *p_memcpy, void *to_write_memcpy, size_t len_memcpy, |
186 | intptr_t *p_final, intptr_t to_write_final, | |
26cc635c | 187 | struct lttng_rseq_state start_value, |
b76e5200 MD |
188 | enum rseq_finish_type type, bool release) |
189 | { | |
190 | RSEQ_INJECT_C(9) | |
191 | ||
b76e5200 MD |
192 | switch (type) { |
193 | case RSEQ_FINISH_SINGLE: | |
194 | RSEQ_FINISH_ASM(p_final, to_write_final, start_value, failure, | |
195 | /* no speculative write */, /* no speculative write */, | |
196 | RSEQ_FINISH_FINAL_STORE_ASM(), | |
197 | RSEQ_FINISH_FINAL_STORE_INPUT(p_final, to_write_final), | |
198 | /* no extra clobber */, /* no arg */, /* no arg */, | |
199 | /* no arg */ | |
200 | ); | |
201 | break; | |
202 | case RSEQ_FINISH_TWO: | |
203 | if (release) { | |
204 | RSEQ_FINISH_ASM(p_final, to_write_final, start_value, failure, | |
205 | RSEQ_FINISH_SPECULATIVE_STORE_ASM(), | |
206 | RSEQ_FINISH_SPECULATIVE_STORE_INPUT(p_spec, to_write_spec), | |
207 | RSEQ_FINISH_FINAL_STORE_RELEASE_ASM(), | |
208 | RSEQ_FINISH_FINAL_STORE_INPUT(p_final, to_write_final), | |
209 | /* no extra clobber */, /* no arg */, /* no arg */, | |
210 | /* no arg */ | |
211 | ); | |
212 | } else { | |
213 | RSEQ_FINISH_ASM(p_final, to_write_final, start_value, failure, | |
214 | RSEQ_FINISH_SPECULATIVE_STORE_ASM(), | |
215 | RSEQ_FINISH_SPECULATIVE_STORE_INPUT(p_spec, to_write_spec), | |
216 | RSEQ_FINISH_FINAL_STORE_ASM(), | |
217 | RSEQ_FINISH_FINAL_STORE_INPUT(p_final, to_write_final), | |
218 | /* no extra clobber */, /* no arg */, /* no arg */, | |
219 | /* no arg */ | |
220 | ); | |
221 | } | |
222 | break; | |
223 | case RSEQ_FINISH_MEMCPY: | |
224 | if (release) { | |
225 | RSEQ_FINISH_ASM(p_final, to_write_final, start_value, failure, | |
226 | RSEQ_FINISH_MEMCPY_STORE_ASM(), | |
227 | RSEQ_FINISH_MEMCPY_STORE_INPUT(p_memcpy, to_write_memcpy, len_memcpy), | |
228 | RSEQ_FINISH_FINAL_STORE_RELEASE_ASM(), | |
229 | RSEQ_FINISH_FINAL_STORE_INPUT(p_final, to_write_final), | |
230 | RSEQ_FINISH_MEMCPY_CLOBBER(), | |
231 | RSEQ_FINISH_MEMCPY_SETUP(), | |
232 | RSEQ_FINISH_MEMCPY_TEARDOWN(), | |
233 | RSEQ_FINISH_MEMCPY_SCRATCH() | |
234 | ); | |
235 | } else { | |
236 | RSEQ_FINISH_ASM(p_final, to_write_final, start_value, failure, | |
237 | RSEQ_FINISH_MEMCPY_STORE_ASM(), | |
238 | RSEQ_FINISH_MEMCPY_STORE_INPUT(p_memcpy, to_write_memcpy, len_memcpy), | |
239 | RSEQ_FINISH_FINAL_STORE_ASM(), | |
240 | RSEQ_FINISH_FINAL_STORE_INPUT(p_final, to_write_final), | |
241 | RSEQ_FINISH_MEMCPY_CLOBBER(), | |
242 | RSEQ_FINISH_MEMCPY_SETUP(), | |
243 | RSEQ_FINISH_MEMCPY_TEARDOWN(), | |
244 | RSEQ_FINISH_MEMCPY_SCRATCH() | |
245 | ); | |
246 | } | |
247 | break; | |
248 | } | |
249 | return true; | |
250 | failure: | |
251 | RSEQ_INJECT_FAILED | |
252 | return false; | |
253 | } | |
26cc635c MD |
254 | #else |
255 | static inline __attribute__((always_inline)) | |
256 | bool __rseq_finish(intptr_t *p_spec, intptr_t to_write_spec, | |
257 | void *p_memcpy, void *to_write_memcpy, size_t len_memcpy, | |
258 | intptr_t *p_final, intptr_t to_write_final, | |
259 | struct lttng_rseq_state start_value, | |
260 | enum rseq_finish_type type, bool release) | |
261 | { | |
262 | return false; | |
263 | } | |
264 | #endif | |
b76e5200 MD |
265 | |
266 | static inline __attribute__((always_inline)) | |
38bfb073 | 267 | bool rseq_finish(intptr_t *p, intptr_t to_write, |
26cc635c | 268 | struct lttng_rseq_state start_value) |
b76e5200 | 269 | { |
38bfb073 | 270 | return __rseq_finish(NULL, 0, |
b76e5200 MD |
271 | NULL, NULL, 0, |
272 | p, to_write, start_value, | |
273 | RSEQ_FINISH_SINGLE, false); | |
274 | } | |
275 | ||
276 | static inline __attribute__((always_inline)) | |
38bfb073 | 277 | bool rseq_finish2(intptr_t *p_spec, intptr_t to_write_spec, |
b76e5200 | 278 | intptr_t *p_final, intptr_t to_write_final, |
26cc635c | 279 | struct lttng_rseq_state start_value) |
b76e5200 | 280 | { |
38bfb073 | 281 | return __rseq_finish(p_spec, to_write_spec, |
b76e5200 MD |
282 | NULL, NULL, 0, |
283 | p_final, to_write_final, start_value, | |
284 | RSEQ_FINISH_TWO, false); | |
285 | } | |
286 | ||
287 | static inline __attribute__((always_inline)) | |
38bfb073 | 288 | bool rseq_finish2_release(intptr_t *p_spec, intptr_t to_write_spec, |
b76e5200 | 289 | intptr_t *p_final, intptr_t to_write_final, |
26cc635c | 290 | struct lttng_rseq_state start_value) |
b76e5200 | 291 | { |
38bfb073 | 292 | return __rseq_finish(p_spec, to_write_spec, |
b76e5200 MD |
293 | NULL, NULL, 0, |
294 | p_final, to_write_final, start_value, | |
295 | RSEQ_FINISH_TWO, true); | |
296 | } | |
297 | ||
298 | static inline __attribute__((always_inline)) | |
38bfb073 MD |
299 | bool rseq_finish_memcpy(void *p_memcpy, void *to_write_memcpy, |
300 | size_t len_memcpy, intptr_t *p_final, intptr_t to_write_final, | |
26cc635c | 301 | struct lttng_rseq_state start_value) |
b76e5200 | 302 | { |
38bfb073 | 303 | return __rseq_finish(NULL, 0, |
b76e5200 MD |
304 | p_memcpy, to_write_memcpy, len_memcpy, |
305 | p_final, to_write_final, start_value, | |
306 | RSEQ_FINISH_MEMCPY, false); | |
307 | } | |
308 | ||
309 | static inline __attribute__((always_inline)) | |
38bfb073 MD |
310 | bool rseq_finish_memcpy_release(void *p_memcpy, void *to_write_memcpy, |
311 | size_t len_memcpy, intptr_t *p_final, intptr_t to_write_final, | |
26cc635c | 312 | struct lttng_rseq_state start_value) |
b76e5200 | 313 | { |
38bfb073 | 314 | return __rseq_finish(NULL, 0, |
b76e5200 MD |
315 | p_memcpy, to_write_memcpy, len_memcpy, |
316 | p_final, to_write_final, start_value, | |
317 | RSEQ_FINISH_MEMCPY, true); | |
318 | } | |
319 | ||
b76e5200 | 320 | #endif /* RSEQ_H_ */ |