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() - 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() 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. It is a macro instead of an static inline function as
44 * some of the types over overloaded (timeout is used for nr_requeue for
45 * example).
46 *
47 * These argument descriptions are the defaults for all
48 * like-named arguments in the following wrappers except where noted below.
49 */
50 #define futex(uaddr, op, val, timeout, uaddr2, val3, opflags) \
51 syscall(SYS_futex, uaddr, op | opflags, val, timeout, uaddr2, val3)
52
53 /**
54 * futex_wait() - block on uaddr with optional timeout
55 * @timeout: relative timeout
56 */
57 static inline int
futex_wait(u_int32_t * uaddr,u_int32_t val,struct timespec * timeout,int opflags)58 futex_wait(u_int32_t *uaddr, u_int32_t val, struct timespec *timeout, int opflags)
59 {
60 return futex(uaddr, FUTEX_WAIT, val, timeout, NULL, 0, opflags);
61 }
62
63 /**
64 * futex_wake() - wake one or more tasks blocked on uaddr
65 * @nr_wake: wake up to this many tasks
66 */
67 static inline int
futex_wake(u_int32_t * uaddr,int nr_wake,int opflags)68 futex_wake(u_int32_t *uaddr, int nr_wake, int opflags)
69 {
70 return futex(uaddr, FUTEX_WAKE, nr_wake, NULL, NULL, 0, opflags);
71 }
72
73 /**
74 * futex_lock_pi() - block on uaddr as a PI mutex
75 */
76 static inline int
futex_lock_pi(u_int32_t * uaddr,struct timespec * timeout,int opflags)77 futex_lock_pi(u_int32_t *uaddr, struct timespec *timeout, int opflags)
78 {
79 return futex(uaddr, FUTEX_LOCK_PI, 0, timeout, NULL, 0, opflags);
80 }
81
82 /**
83 * futex_unlock_pi() - release uaddr as a PI mutex, waking the top waiter
84 */
85 static inline int
futex_unlock_pi(u_int32_t * uaddr,int opflags)86 futex_unlock_pi(u_int32_t *uaddr, int opflags)
87 {
88 return futex(uaddr, FUTEX_UNLOCK_PI, 0, NULL, NULL, 0, opflags);
89 }
90
91 /**
92 * futex_cmp_requeue() - requeue tasks from uaddr to uaddr2
93 * @nr_wake: wake up to this many tasks
94 * @nr_requeue: requeue up to this many tasks
95 */
96 static inline int
futex_cmp_requeue(u_int32_t * uaddr,u_int32_t val,u_int32_t * uaddr2,int nr_wake,int nr_requeue,int opflags)97 futex_cmp_requeue(u_int32_t *uaddr, u_int32_t val, u_int32_t *uaddr2, int nr_wake,
98 int nr_requeue, int opflags)
99 {
100 return futex(uaddr, FUTEX_CMP_REQUEUE, nr_wake, nr_requeue, uaddr2,
101 val, opflags);
102 }
103
104 /**
105 * futex_wait_requeue_pi() - block on uaddr and prepare to requeue to uaddr2
106 * @uaddr: non-PI futex source
107 * @uaddr2: PI futex target
108 *
109 * This is the first half of the requeue_pi mechanism. It shall always be
110 * paired with futex_cmp_requeue_pi().
111 */
112 static inline int
futex_wait_requeue_pi(u_int32_t * uaddr,u_int32_t val,u_int32_t * uaddr2,struct timespec * timeout,int opflags)113 futex_wait_requeue_pi(u_int32_t *uaddr, u_int32_t val, u_int32_t *uaddr2,
114 struct timespec *timeout, int opflags)
115 {
116 return futex(uaddr, FUTEX_WAIT_REQUEUE_PI, val, timeout, uaddr2, 0,
117 opflags);
118 }
119
120 /**
121 * futex_cmp_requeue_pi() - requeue tasks from uaddr to uaddr2
122 * @uaddr: non-PI futex source
123 * @uaddr2: PI futex target
124 * @nr_requeue: requeue up to this many tasks
125 *
126 * This is the second half of the requeue_pi mechanism. It shall always be
127 * paired with futex_wait_requeue_pi(). The first waker is always awoken.
128 */
129 static inline int
futex_cmp_requeue_pi(u_int32_t * uaddr,u_int32_t val,u_int32_t * uaddr2,int nr_requeue,int opflags)130 futex_cmp_requeue_pi(u_int32_t *uaddr, u_int32_t val, u_int32_t *uaddr2,
131 int nr_requeue, int opflags)
132 {
133 return futex(uaddr, FUTEX_CMP_REQUEUE_PI, 1, nr_requeue, uaddr2,
134 val, opflags);
135 }
136
137 #endif /* _FUTEX_H */
138