1 /* SPDX-License-Identifier: GPL-2.0 */
2 /*
3 * Glibc independent futex library for testing kernel functionality.
4 * Shamelessly stolen from Darren Hart <dvhltc@us.ibm.com>
5 * http://git.kernel.org/cgit/linux/kernel/git/dvhart/futextest.git/
6 */
7
8 #ifndef _FUTEX_H
9 #define _FUTEX_H
10
11 #include <unistd.h>
12 #include <sys/syscall.h>
13 #include <sys/types.h>
14 #include <linux/futex.h>
15
16 struct bench_futex_parameters {
17 bool silent;
18 bool fshared;
19 bool mlockall;
20 bool multi; /* lock-pi */
21 bool pi; /* requeue-pi */
22 bool broadcast; /* requeue */
23 unsigned int runtime; /* seconds*/
24 unsigned int nthreads;
25 unsigned int nfutexes;
26 unsigned int nwakes;
27 unsigned int nrequeue;
28 };
29
30 /**
31 * futex_syscall() - SYS_futex syscall wrapper
32 * @uaddr: address of first futex
33 * @op: futex op code
34 * @val: typically expected value of uaddr, but varies by op
35 * @timeout: typically an absolute struct timespec (except where noted
36 * otherwise). Overloaded by some ops
37 * @uaddr2: address of second futex for some ops
38 * @val3: varies by op
39 * @opflags: flags to be bitwise OR'd with op, such as FUTEX_PRIVATE_FLAG
40 *
41 * futex_syscall() is used by all the following futex op wrappers. It can also be
42 * used for misuse and abuse testing. Generally, the specific op wrappers
43 * should be used instead.
44 *
45 * These argument descriptions are the defaults for all
46 * like-named arguments in the following wrappers except where noted below.
47 */
48 static inline int
49 futex_syscall(volatile u_int32_t *uaddr, int op, u_int32_t val, struct timespec *timeout,
50 volatile u_int32_t *uaddr2, int val3, int opflags)
51 {
52 return syscall(SYS_futex, uaddr, op | opflags, val, timeout, uaddr2, val3);
53 }
54
55 static inline int
56 futex_syscall_nr_requeue(volatile u_int32_t *uaddr, int op, u_int32_t val, int nr_requeue,
57 volatile u_int32_t *uaddr2, int val3, int opflags)
58 {
59 return syscall(SYS_futex, uaddr, op | opflags, val, nr_requeue, uaddr2, val3);
60 }
61
62 /**
63 * futex_wait() - block on uaddr with optional timeout
64 * @timeout: relative timeout
65 */
66 static inline int
67 futex_wait(u_int32_t *uaddr, u_int32_t val, struct timespec *timeout, int opflags)
68 {
69 return futex_syscall(uaddr, FUTEX_WAIT, val, timeout, NULL, 0, opflags);
70 }
71
72 /**
73 * futex_wake() - wake one or more tasks blocked on uaddr
74 * @nr_wake: wake up to this many tasks
75 */
76 static inline int
77 futex_wake(u_int32_t *uaddr, int nr_wake, int opflags)
78 {
79 return futex_syscall(uaddr, FUTEX_WAKE, nr_wake, NULL, NULL, 0, opflags);
80 }
81
82 /**
83 * futex_lock_pi() - block on uaddr as a PI mutex
84 */
85 static inline int
86 futex_lock_pi(u_int32_t *uaddr, struct timespec *timeout, int opflags)
87 {
88 return futex_syscall(uaddr, FUTEX_LOCK_PI, 0, timeout, NULL, 0, opflags);
89 }
90
91 /**
92 * futex_unlock_pi() - release uaddr as a PI mutex, waking the top waiter
93 */
94 static inline int
95 futex_unlock_pi(u_int32_t *uaddr, int opflags)
96 {
97 return futex_syscall(uaddr, FUTEX_UNLOCK_PI, 0, NULL, NULL, 0, opflags);
98 }
99
100 /**
101 * futex_cmp_requeue() - requeue tasks from uaddr to uaddr2
102 * @nr_wake: wake up to this many tasks
103 * @nr_requeue: requeue up to this many tasks
104 */
105 static inline int
106 futex_cmp_requeue(u_int32_t *uaddr, u_int32_t val, u_int32_t *uaddr2, int nr_wake,
107 int nr_requeue, int opflags)
108 {
109 return futex_syscall_nr_requeue(uaddr, FUTEX_CMP_REQUEUE, nr_wake, nr_requeue, uaddr2,
110 val, opflags);
111 }
112
113 /**
114 * futex_wait_requeue_pi() - block on uaddr and prepare to requeue to uaddr2
115 * @uaddr: non-PI futex source
116 * @uaddr2: PI futex target
117 *
118 * This is the first half of the requeue_pi mechanism. It shall always be
119 * paired with futex_cmp_requeue_pi().
120 */
121 static inline int
122 futex_wait_requeue_pi(u_int32_t *uaddr, u_int32_t val, u_int32_t *uaddr2,
123 struct timespec *timeout, int opflags)
124 {
125 return futex_syscall(uaddr, FUTEX_WAIT_REQUEUE_PI, val, timeout, uaddr2, 0,
126 opflags);
127 }
128
129 /**
130 * futex_cmp_requeue_pi() - requeue tasks from uaddr to uaddr2
131 * @uaddr: non-PI futex source
132 * @uaddr2: PI futex target
133 * @nr_requeue: requeue up to this many tasks
134 *
135 * This is the second half of the requeue_pi mechanism. It shall always be
136 * paired with futex_wait_requeue_pi(). The first waker is always awoken.
137 */
138 static inline int
139 futex_cmp_requeue_pi(u_int32_t *uaddr, u_int32_t val, u_int32_t *uaddr2,
140 int nr_requeue, int opflags)
141 {
142 return futex_syscall_nr_requeue(uaddr, FUTEX_CMP_REQUEUE_PI, 1, nr_requeue, uaddr2,
143 val, opflags);
144 }
145
146 #endif /* _FUTEX_H */
147
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