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49617de1 MD |
1 | #ifndef _URCU_FUTEX_H |
2 | #define _URCU_FUTEX_H | |
3 | ||
4 | /* | |
5 | * urcu-futex.h | |
6 | * | |
7 | * Userspace RCU - sys_futex/compat_futex header. | |
8 | * | |
3282a76b MD |
9 | * Copyright 2011-2012 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com> |
10 | * | |
49617de1 MD |
11 | * This library is free software; you can redistribute it and/or |
12 | * modify it under the terms of the GNU Lesser General Public | |
13 | * License as published by the Free Software Foundation; either | |
14 | * version 2.1 of the License, or (at your option) any later version. | |
15 | * | |
16 | * This library is distributed in the hope that it will be useful, | |
17 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
18 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
19 | * Lesser General Public License for more details. | |
20 | * | |
21 | * You should have received a copy of the GNU Lesser General Public | |
22 | * License along with this library; if not, write to the Free Software | |
23 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA | |
24 | */ | |
25 | ||
26 | #include <urcu/config.h> | |
32146086 | 27 | #include <errno.h> |
6d841bc2 | 28 | #include <stdint.h> |
6a29bfc1 | 29 | #include <time.h> |
49617de1 | 30 | |
2de13c16 MD |
31 | #ifdef CONFIG_RCU_HAVE_FUTEX |
32 | ||
33 | #include <unistd.h> | |
34 | #include <errno.h> | |
35 | #include <urcu/compiler.h> | |
36 | #include <urcu/arch.h> | |
37 | ||
38 | #elif defined(__FreeBSD__) | |
39 | ||
40 | #include <sys/types.h> | |
41 | #include <sys/umtx.h> | |
42 | ||
43 | #endif | |
44 | ||
36bc70a8 MD |
45 | #ifdef __cplusplus |
46 | extern "C" { | |
67ecffc0 | 47 | #endif |
36bc70a8 | 48 | |
49617de1 MD |
49 | #define FUTEX_WAIT 0 |
50 | #define FUTEX_WAKE 1 | |
51 | ||
52 | /* | |
53 | * sys_futex compatibility header. | |
54 | * Use *only* *either of* futex_noasync OR futex_async on a given address. | |
55 | * | |
56 | * futex_noasync cannot be executed in signal handlers, but ensures that | |
57 | * it will be put in a wait queue even in compatibility mode. | |
58 | * | |
59 | * futex_async is signal-handler safe for the wakeup. It uses polling | |
60 | * on the wait-side in compatibility mode. | |
b0a841b4 MD |
61 | * |
62 | * BEWARE: sys_futex() FUTEX_WAIT may return early if interrupted | |
63 | * (returns EINTR). | |
49617de1 MD |
64 | */ |
65 | ||
42dfe454 MD |
66 | extern int compat_futex_noasync(int32_t *uaddr, int op, int32_t val, |
67 | const struct timespec *timeout, int32_t *uaddr2, int32_t val3); | |
68 | extern int compat_futex_async(int32_t *uaddr, int op, int32_t val, | |
69 | const struct timespec *timeout, int32_t *uaddr2, int32_t val3); | |
70 | ||
02be5561 | 71 | #ifdef CONFIG_RCU_HAVE_FUTEX |
42dfe454 | 72 | |
42dfe454 MD |
73 | static inline int futex(int32_t *uaddr, int op, int32_t val, |
74 | const struct timespec *timeout, int32_t *uaddr2, int32_t val3) | |
75 | { | |
76 | return syscall(__NR_futex, uaddr, op, val, timeout, | |
77 | uaddr2, val3); | |
78 | } | |
79 | ||
80 | static inline int futex_noasync(int32_t *uaddr, int op, int32_t val, | |
81 | const struct timespec *timeout, int32_t *uaddr2, int32_t val3) | |
82 | { | |
83 | int ret; | |
84 | ||
85 | ret = futex(uaddr, op, val, timeout, uaddr2, val3); | |
86 | if (caa_unlikely(ret < 0 && errno == ENOSYS)) { | |
b2633d21 MD |
87 | /* |
88 | * The fallback on ENOSYS is the async-safe version of | |
89 | * the compat futex implementation, because the | |
90 | * async-safe compat implementation allows being used | |
91 | * concurrently with calls to futex(). Indeed, sys_futex | |
92 | * FUTEX_WAIT, on some architectures (mips and parisc), | |
93 | * within a given process, spuriously return ENOSYS due | |
94 | * to signal restart bugs on some kernel versions. | |
95 | */ | |
96 | return compat_futex_async(uaddr, op, val, timeout, | |
42dfe454 MD |
97 | uaddr2, val3); |
98 | } | |
99 | return ret; | |
100 | ||
101 | } | |
102 | ||
103 | static inline int futex_async(int32_t *uaddr, int op, int32_t val, | |
104 | const struct timespec *timeout, int32_t *uaddr2, int32_t val3) | |
105 | { | |
106 | int ret; | |
107 | ||
108 | ret = futex(uaddr, op, val, timeout, uaddr2, val3); | |
109 | if (caa_unlikely(ret < 0 && errno == ENOSYS)) { | |
110 | return compat_futex_async(uaddr, op, val, timeout, | |
111 | uaddr2, val3); | |
112 | } | |
113 | return ret; | |
114 | } | |
115 | ||
32146086 AX |
116 | #elif defined(__FreeBSD__) |
117 | ||
32146086 | 118 | static inline int futex_async(int32_t *uaddr, int op, int32_t val, |
0d657320 MJ |
119 | const struct timespec *timeout, |
120 | int32_t *uaddr2 __attribute__((unused)), | |
121 | int32_t val3 __attribute__((unused))) | |
32146086 AX |
122 | { |
123 | int umtx_op; | |
124 | void *umtx_uaddr = NULL, *umtx_uaddr2 = NULL; | |
125 | struct _umtx_time umtx_timeout = { | |
126 | ._flags = UMTX_ABSTIME, | |
127 | ._clockid = CLOCK_MONOTONIC, | |
128 | }; | |
129 | ||
130 | switch (op) { | |
131 | case FUTEX_WAIT: | |
132 | /* On FreeBSD, a "u_int" is a 32-bit integer. */ | |
133 | umtx_op = UMTX_OP_WAIT_UINT; | |
134 | if (timeout != NULL) { | |
135 | umtx_timeout._timeout = *timeout; | |
136 | umtx_uaddr = (void *) sizeof(umtx_timeout); | |
137 | umtx_uaddr2 = (void *) &umtx_timeout; | |
138 | } | |
139 | break; | |
140 | case FUTEX_WAKE: | |
141 | umtx_op = UMTX_OP_WAKE; | |
142 | break; | |
143 | default: | |
144 | errno = EINVAL; | |
145 | return -1; | |
146 | } | |
147 | ||
148 | return _umtx_op(uaddr, umtx_op, (uint32_t) val, umtx_uaddr, | |
149 | umtx_uaddr2); | |
150 | } | |
151 | ||
152 | static inline int futex_noasync(int32_t *uaddr, int op, int32_t val, | |
153 | const struct timespec *timeout, int32_t *uaddr2, int32_t val3) | |
154 | { | |
155 | return futex_async(uaddr, op, val, timeout, uaddr2, val3); | |
156 | } | |
157 | ||
bb109fb6 MJ |
158 | #elif defined(__CYGWIN__) |
159 | ||
160 | /* | |
161 | * The futex_noasync compat code uses a weak symbol to share state across | |
162 | * different shared object which is not possible on Windows with the | |
163 | * Portable Executable format. Use the async compat code for both cases. | |
164 | */ | |
165 | static inline int futex_noasync(int32_t *uaddr, int op, int32_t val, | |
166 | const struct timespec *timeout, int32_t *uaddr2, int32_t val3) | |
167 | { | |
168 | return compat_futex_async(uaddr, op, val, timeout, uaddr2, val3); | |
169 | } | |
170 | ||
171 | static inline int futex_async(int32_t *uaddr, int op, int32_t val, | |
172 | const struct timespec *timeout, int32_t *uaddr2, int32_t val3) | |
173 | { | |
174 | return compat_futex_async(uaddr, op, val, timeout, uaddr2, val3); | |
175 | } | |
176 | ||
49617de1 | 177 | #else |
42dfe454 MD |
178 | |
179 | static inline int futex_noasync(int32_t *uaddr, int op, int32_t val, | |
180 | const struct timespec *timeout, int32_t *uaddr2, int32_t val3) | |
181 | { | |
182 | return compat_futex_noasync(uaddr, op, val, timeout, uaddr2, val3); | |
183 | } | |
184 | ||
185 | static inline int futex_async(int32_t *uaddr, int op, int32_t val, | |
186 | const struct timespec *timeout, int32_t *uaddr2, int32_t val3) | |
187 | { | |
188 | return compat_futex_async(uaddr, op, val, timeout, uaddr2, val3); | |
189 | } | |
190 | ||
49617de1 MD |
191 | #endif |
192 | ||
67ecffc0 | 193 | #ifdef __cplusplus |
36bc70a8 MD |
194 | } |
195 | #endif | |
196 | ||
49617de1 | 197 | #endif /* _URCU_FUTEX_H */ |