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2874c5fd | 1 | /* SPDX-License-Identifier: GPL-2.0-or-later */ |
2aa8470f DH |
2 | /****************************************************************************** |
3 | * | |
4 | * Copyright © International Business Machines Corp., 2009 | |
5 | * | |
2aa8470f DH |
6 | * DESCRIPTION |
7 | * Glibc independent futex library for testing kernel functionality. | |
8 | * | |
9 | * AUTHOR | |
10 | * Darren Hart <dvhart@linux.intel.com> | |
11 | * | |
12 | * HISTORY | |
13 | * 2009-Nov-6: Initial version by Darren Hart <dvhart@linux.intel.com> | |
14 | * | |
15 | *****************************************************************************/ | |
16 | ||
17 | #ifndef _FUTEXTEST_H | |
18 | #define _FUTEXTEST_H | |
19 | ||
20 | #include <unistd.h> | |
21 | #include <sys/syscall.h> | |
22 | #include <sys/types.h> | |
23 | #include <linux/futex.h> | |
24 | ||
25 | typedef volatile u_int32_t futex_t; | |
26 | #define FUTEX_INITIALIZER 0 | |
27 | ||
28 | /* Define the newer op codes if the system header file is not up to date. */ | |
29 | #ifndef FUTEX_WAIT_BITSET | |
30 | #define FUTEX_WAIT_BITSET 9 | |
31 | #endif | |
32 | #ifndef FUTEX_WAKE_BITSET | |
33 | #define FUTEX_WAKE_BITSET 10 | |
34 | #endif | |
35 | #ifndef FUTEX_WAIT_REQUEUE_PI | |
36 | #define FUTEX_WAIT_REQUEUE_PI 11 | |
37 | #endif | |
38 | #ifndef FUTEX_CMP_REQUEUE_PI | |
39 | #define FUTEX_CMP_REQUEUE_PI 12 | |
40 | #endif | |
41 | #ifndef FUTEX_WAIT_REQUEUE_PI_PRIVATE | |
42 | #define FUTEX_WAIT_REQUEUE_PI_PRIVATE (FUTEX_WAIT_REQUEUE_PI | \ | |
43 | FUTEX_PRIVATE_FLAG) | |
44 | #endif | |
45 | #ifndef FUTEX_REQUEUE_PI_PRIVATE | |
46 | #define FUTEX_CMP_REQUEUE_PI_PRIVATE (FUTEX_CMP_REQUEUE_PI | \ | |
47 | FUTEX_PRIVATE_FLAG) | |
48 | #endif | |
49 | ||
50 | /** | |
51 | * futex() - SYS_futex syscall wrapper | |
52 | * @uaddr: address of first futex | |
53 | * @op: futex op code | |
54 | * @val: typically expected value of uaddr, but varies by op | |
55 | * @timeout: typically an absolute struct timespec (except where noted | |
56 | * otherwise). Overloaded by some ops | |
57 | * @uaddr2: address of second futex for some ops\ | |
58 | * @val3: varies by op | |
59 | * @opflags: flags to be bitwise OR'd with op, such as FUTEX_PRIVATE_FLAG | |
60 | * | |
61 | * futex() is used by all the following futex op wrappers. It can also be | |
62 | * used for misuse and abuse testing. Generally, the specific op wrappers | |
63 | * should be used instead. It is a macro instead of an static inline function as | |
64 | * some of the types over overloaded (timeout is used for nr_requeue for | |
65 | * example). | |
66 | * | |
67 | * These argument descriptions are the defaults for all | |
68 | * like-named arguments in the following wrappers except where noted below. | |
69 | */ | |
70 | #define futex(uaddr, op, val, timeout, uaddr2, val3, opflags) \ | |
71 | syscall(SYS_futex, uaddr, op | opflags, val, timeout, uaddr2, val3) | |
72 | ||
73 | /** | |
74 | * futex_wait() - block on uaddr with optional timeout | |
75 | * @timeout: relative timeout | |
76 | */ | |
77 | static inline int | |
78 | futex_wait(futex_t *uaddr, futex_t val, struct timespec *timeout, int opflags) | |
79 | { | |
80 | return futex(uaddr, FUTEX_WAIT, val, timeout, NULL, 0, opflags); | |
81 | } | |
82 | ||
83 | /** | |
84 | * futex_wake() - wake one or more tasks blocked on uaddr | |
85 | * @nr_wake: wake up to this many tasks | |
86 | */ | |
87 | static inline int | |
88 | futex_wake(futex_t *uaddr, int nr_wake, int opflags) | |
89 | { | |
90 | return futex(uaddr, FUTEX_WAKE, nr_wake, NULL, NULL, 0, opflags); | |
91 | } | |
92 | ||
93 | /** | |
94 | * futex_wait_bitset() - block on uaddr with bitset | |
95 | * @bitset: bitset to be used with futex_wake_bitset | |
96 | */ | |
97 | static inline int | |
98 | futex_wait_bitset(futex_t *uaddr, futex_t val, struct timespec *timeout, | |
99 | u_int32_t bitset, int opflags) | |
100 | { | |
101 | return futex(uaddr, FUTEX_WAIT_BITSET, val, timeout, NULL, bitset, | |
102 | opflags); | |
103 | } | |
104 | ||
105 | /** | |
106 | * futex_wake_bitset() - wake one or more tasks blocked on uaddr with bitset | |
107 | * @bitset: bitset to compare with that used in futex_wait_bitset | |
108 | */ | |
109 | static inline int | |
110 | futex_wake_bitset(futex_t *uaddr, int nr_wake, u_int32_t bitset, int opflags) | |
111 | { | |
112 | return futex(uaddr, FUTEX_WAKE_BITSET, nr_wake, NULL, NULL, bitset, | |
113 | opflags); | |
114 | } | |
115 | ||
116 | /** | |
117 | * futex_lock_pi() - block on uaddr as a PI mutex | |
118 | * @detect: whether (1) or not (0) to perform deadlock detection | |
119 | */ | |
120 | static inline int | |
121 | futex_lock_pi(futex_t *uaddr, struct timespec *timeout, int detect, | |
122 | int opflags) | |
123 | { | |
124 | return futex(uaddr, FUTEX_LOCK_PI, detect, timeout, NULL, 0, opflags); | |
125 | } | |
126 | ||
127 | /** | |
128 | * futex_unlock_pi() - release uaddr as a PI mutex, waking the top waiter | |
129 | */ | |
130 | static inline int | |
131 | futex_unlock_pi(futex_t *uaddr, int opflags) | |
132 | { | |
133 | return futex(uaddr, FUTEX_UNLOCK_PI, 0, NULL, NULL, 0, opflags); | |
134 | } | |
135 | ||
136 | /** | |
137 | * futex_wake_op() - FIXME: COME UP WITH A GOOD ONE LINE DESCRIPTION | |
138 | */ | |
139 | static inline int | |
140 | futex_wake_op(futex_t *uaddr, futex_t *uaddr2, int nr_wake, int nr_wake2, | |
141 | int wake_op, int opflags) | |
142 | { | |
143 | return futex(uaddr, FUTEX_WAKE_OP, nr_wake, nr_wake2, uaddr2, wake_op, | |
144 | opflags); | |
145 | } | |
146 | ||
147 | /** | |
148 | * futex_requeue() - requeue without expected value comparison, deprecated | |
149 | * @nr_wake: wake up to this many tasks | |
150 | * @nr_requeue: requeue up to this many tasks | |
151 | * | |
152 | * Due to its inherently racy implementation, futex_requeue() is deprecated in | |
153 | * favor of futex_cmp_requeue(). | |
154 | */ | |
155 | static inline int | |
156 | futex_requeue(futex_t *uaddr, futex_t *uaddr2, int nr_wake, int nr_requeue, | |
157 | int opflags) | |
158 | { | |
159 | return futex(uaddr, FUTEX_REQUEUE, nr_wake, nr_requeue, uaddr2, 0, | |
160 | opflags); | |
161 | } | |
162 | ||
163 | /** | |
164 | * futex_cmp_requeue() - requeue tasks from uaddr to uaddr2 | |
165 | * @nr_wake: wake up to this many tasks | |
166 | * @nr_requeue: requeue up to this many tasks | |
167 | */ | |
168 | static inline int | |
169 | futex_cmp_requeue(futex_t *uaddr, futex_t val, futex_t *uaddr2, int nr_wake, | |
170 | int nr_requeue, int opflags) | |
171 | { | |
172 | return futex(uaddr, FUTEX_CMP_REQUEUE, nr_wake, nr_requeue, uaddr2, | |
173 | val, opflags); | |
174 | } | |
175 | ||
176 | /** | |
177 | * futex_wait_requeue_pi() - block on uaddr and prepare to requeue to uaddr2 | |
178 | * @uaddr: non-PI futex source | |
179 | * @uaddr2: PI futex target | |
180 | * | |
181 | * This is the first half of the requeue_pi mechanism. It shall always be | |
182 | * paired with futex_cmp_requeue_pi(). | |
183 | */ | |
184 | static inline int | |
185 | futex_wait_requeue_pi(futex_t *uaddr, futex_t val, futex_t *uaddr2, | |
186 | struct timespec *timeout, int opflags) | |
187 | { | |
188 | return futex(uaddr, FUTEX_WAIT_REQUEUE_PI, val, timeout, uaddr2, 0, | |
189 | opflags); | |
190 | } | |
191 | ||
192 | /** | |
193 | * futex_cmp_requeue_pi() - requeue tasks from uaddr to uaddr2 (PI aware) | |
194 | * @uaddr: non-PI futex source | |
195 | * @uaddr2: PI futex target | |
196 | * @nr_wake: wake up to this many tasks | |
197 | * @nr_requeue: requeue up to this many tasks | |
198 | */ | |
199 | static inline int | |
200 | futex_cmp_requeue_pi(futex_t *uaddr, futex_t val, futex_t *uaddr2, int nr_wake, | |
201 | int nr_requeue, int opflags) | |
202 | { | |
203 | return futex(uaddr, FUTEX_CMP_REQUEUE_PI, nr_wake, nr_requeue, uaddr2, | |
204 | val, opflags); | |
205 | } | |
206 | ||
207 | /** | |
208 | * futex_cmpxchg() - atomic compare and exchange | |
209 | * @uaddr: The address of the futex to be modified | |
210 | * @oldval: The expected value of the futex | |
211 | * @newval: The new value to try and assign the futex | |
212 | * | |
213 | * Implement cmpxchg using gcc atomic builtins. | |
214 | * http://gcc.gnu.org/onlinedocs/gcc-4.1.0/gcc/Atomic-Builtins.html | |
215 | * | |
216 | * Return the old futex value. | |
217 | */ | |
218 | static inline u_int32_t | |
219 | futex_cmpxchg(futex_t *uaddr, u_int32_t oldval, u_int32_t newval) | |
220 | { | |
221 | return __sync_val_compare_and_swap(uaddr, oldval, newval); | |
222 | } | |
223 | ||
224 | /** | |
225 | * futex_dec() - atomic decrement of the futex value | |
226 | * @uaddr: The address of the futex to be modified | |
227 | * | |
228 | * Return the new futex value. | |
229 | */ | |
230 | static inline u_int32_t | |
231 | futex_dec(futex_t *uaddr) | |
232 | { | |
233 | return __sync_sub_and_fetch(uaddr, 1); | |
234 | } | |
235 | ||
236 | /** | |
237 | * futex_inc() - atomic increment of the futex value | |
238 | * @uaddr: the address of the futex to be modified | |
239 | * | |
240 | * Return the new futex value. | |
241 | */ | |
242 | static inline u_int32_t | |
243 | futex_inc(futex_t *uaddr) | |
244 | { | |
245 | return __sync_add_and_fetch(uaddr, 1); | |
246 | } | |
247 | ||
248 | /** | |
249 | * futex_set() - atomic decrement of the futex value | |
250 | * @uaddr: the address of the futex to be modified | |
251 | * @newval: New value for the atomic_t | |
252 | * | |
253 | * Return the new futex value. | |
254 | */ | |
255 | static inline u_int32_t | |
256 | futex_set(futex_t *uaddr, u_int32_t newval) | |
257 | { | |
258 | *uaddr = newval; | |
259 | return newval; | |
260 | } | |
261 | ||
262 | #endif |