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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> | |
ca91060e MJ |
27 | #include <urcu/syscall-compat.h> |
28 | ||
32146086 | 29 | #include <errno.h> |
6d841bc2 | 30 | #include <stdint.h> |
6a29bfc1 | 31 | #include <time.h> |
49617de1 | 32 | |
36bc70a8 MD |
33 | #ifdef __cplusplus |
34 | extern "C" { | |
67ecffc0 | 35 | #endif |
36bc70a8 | 36 | |
49617de1 MD |
37 | #define FUTEX_WAIT 0 |
38 | #define FUTEX_WAKE 1 | |
39 | ||
40 | /* | |
41 | * sys_futex compatibility header. | |
42 | * Use *only* *either of* futex_noasync OR futex_async on a given address. | |
43 | * | |
44 | * futex_noasync cannot be executed in signal handlers, but ensures that | |
45 | * it will be put in a wait queue even in compatibility mode. | |
46 | * | |
47 | * futex_async is signal-handler safe for the wakeup. It uses polling | |
48 | * on the wait-side in compatibility mode. | |
b0a841b4 MD |
49 | * |
50 | * BEWARE: sys_futex() FUTEX_WAIT may return early if interrupted | |
51 | * (returns EINTR). | |
49617de1 MD |
52 | */ |
53 | ||
42dfe454 MD |
54 | extern int compat_futex_noasync(int32_t *uaddr, int op, int32_t val, |
55 | const struct timespec *timeout, int32_t *uaddr2, int32_t val3); | |
56 | extern int compat_futex_async(int32_t *uaddr, int op, int32_t val, | |
57 | const struct timespec *timeout, int32_t *uaddr2, int32_t val3); | |
58 | ||
0afb29b2 | 59 | #if (defined(__linux__) && defined(__NR_futex)) |
ca91060e MJ |
60 | |
61 | /* For backwards compat */ | |
62 | #define CONFIG_RCU_HAVE_FUTEX 1 | |
42dfe454 MD |
63 | |
64 | #include <unistd.h> | |
65 | #include <errno.h> | |
66 | #include <urcu/compiler.h> | |
999991c6 | 67 | #include <urcu/arch.h> |
42dfe454 MD |
68 | |
69 | static inline int futex(int32_t *uaddr, int op, int32_t val, | |
70 | const struct timespec *timeout, int32_t *uaddr2, int32_t val3) | |
71 | { | |
72 | return syscall(__NR_futex, uaddr, op, val, timeout, | |
73 | uaddr2, val3); | |
74 | } | |
75 | ||
76 | static inline int futex_noasync(int32_t *uaddr, int op, int32_t val, | |
77 | const struct timespec *timeout, int32_t *uaddr2, int32_t val3) | |
78 | { | |
79 | int ret; | |
80 | ||
81 | ret = futex(uaddr, op, val, timeout, uaddr2, val3); | |
82 | if (caa_unlikely(ret < 0 && errno == ENOSYS)) { | |
b2633d21 MD |
83 | /* |
84 | * The fallback on ENOSYS is the async-safe version of | |
85 | * the compat futex implementation, because the | |
86 | * async-safe compat implementation allows being used | |
87 | * concurrently with calls to futex(). Indeed, sys_futex | |
88 | * FUTEX_WAIT, on some architectures (mips and parisc), | |
89 | * within a given process, spuriously return ENOSYS due | |
90 | * to signal restart bugs on some kernel versions. | |
91 | */ | |
92 | return compat_futex_async(uaddr, op, val, timeout, | |
42dfe454 MD |
93 | uaddr2, val3); |
94 | } | |
95 | return ret; | |
96 | ||
97 | } | |
98 | ||
99 | static inline int futex_async(int32_t *uaddr, int op, int32_t val, | |
100 | const struct timespec *timeout, int32_t *uaddr2, int32_t val3) | |
101 | { | |
102 | int ret; | |
103 | ||
104 | ret = futex(uaddr, op, val, timeout, uaddr2, val3); | |
105 | if (caa_unlikely(ret < 0 && errno == ENOSYS)) { | |
106 | return compat_futex_async(uaddr, op, val, timeout, | |
107 | uaddr2, val3); | |
108 | } | |
109 | return ret; | |
110 | } | |
111 | ||
32146086 AX |
112 | #elif defined(__FreeBSD__) |
113 | ||
114 | #include <sys/types.h> | |
115 | #include <sys/umtx.h> | |
116 | ||
117 | static inline int futex_async(int32_t *uaddr, int op, int32_t val, | |
a142df4e MJ |
118 | const struct timespec *timeout, |
119 | int32_t *uaddr2 __attribute__((unused)), | |
120 | int32_t val3 __attribute__((unused))) | |
32146086 AX |
121 | { |
122 | int umtx_op; | |
123 | void *umtx_uaddr = NULL, *umtx_uaddr2 = NULL; | |
124 | struct _umtx_time umtx_timeout = { | |
125 | ._flags = UMTX_ABSTIME, | |
126 | ._clockid = CLOCK_MONOTONIC, | |
127 | }; | |
128 | ||
129 | switch (op) { | |
130 | case FUTEX_WAIT: | |
131 | /* On FreeBSD, a "u_int" is a 32-bit integer. */ | |
132 | umtx_op = UMTX_OP_WAIT_UINT; | |
133 | if (timeout != NULL) { | |
134 | umtx_timeout._timeout = *timeout; | |
135 | umtx_uaddr = (void *) sizeof(umtx_timeout); | |
136 | umtx_uaddr2 = (void *) &umtx_timeout; | |
137 | } | |
138 | break; | |
139 | case FUTEX_WAKE: | |
140 | umtx_op = UMTX_OP_WAKE; | |
141 | break; | |
142 | default: | |
143 | errno = EINVAL; | |
144 | return -1; | |
145 | } | |
146 | ||
147 | return _umtx_op(uaddr, umtx_op, (uint32_t) val, umtx_uaddr, | |
148 | umtx_uaddr2); | |
149 | } | |
150 | ||
151 | static inline int futex_noasync(int32_t *uaddr, int op, int32_t val, | |
152 | const struct timespec *timeout, int32_t *uaddr2, int32_t val3) | |
153 | { | |
154 | return futex_async(uaddr, op, val, timeout, uaddr2, val3); | |
155 | } | |
156 | ||
bb109fb6 MJ |
157 | #elif defined(__CYGWIN__) |
158 | ||
159 | /* | |
160 | * The futex_noasync compat code uses a weak symbol to share state across | |
161 | * different shared object which is not possible on Windows with the | |
162 | * Portable Executable format. Use the async compat code for both cases. | |
163 | */ | |
164 | static inline int futex_noasync(int32_t *uaddr, int op, int32_t val, | |
165 | const struct timespec *timeout, int32_t *uaddr2, int32_t val3) | |
166 | { | |
167 | return compat_futex_async(uaddr, op, val, timeout, uaddr2, val3); | |
168 | } | |
169 | ||
170 | static inline int futex_async(int32_t *uaddr, int op, int32_t val, | |
171 | const struct timespec *timeout, int32_t *uaddr2, int32_t val3) | |
172 | { | |
173 | return compat_futex_async(uaddr, op, val, timeout, uaddr2, val3); | |
174 | } | |
175 | ||
49617de1 | 176 | #else |
42dfe454 MD |
177 | |
178 | static inline int futex_noasync(int32_t *uaddr, int op, int32_t val, | |
179 | const struct timespec *timeout, int32_t *uaddr2, int32_t val3) | |
180 | { | |
181 | return compat_futex_noasync(uaddr, op, val, timeout, uaddr2, val3); | |
182 | } | |
183 | ||
184 | static inline int futex_async(int32_t *uaddr, int op, int32_t val, | |
185 | const struct timespec *timeout, int32_t *uaddr2, int32_t val3) | |
186 | { | |
187 | return compat_futex_async(uaddr, op, val, timeout, uaddr2, val3); | |
188 | } | |
189 | ||
49617de1 MD |
190 | #endif |
191 | ||
67ecffc0 | 192 | #ifdef __cplusplus |
36bc70a8 MD |
193 | } |
194 | #endif | |
195 | ||
49617de1 | 196 | #endif /* _URCU_FUTEX_H */ |