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 <stdbool.h>
12 #include <unistd.h>
13 #include <sys/syscall.h>
14 #include <sys/types.h>
15 #include <linux/futex.h>
16
17 struct bench_futex_parameters {
18 bool silent;
19 bool fshared;
20 bool mlockall;
21 bool multi; /* lock-pi */
22 bool pi; /* requeue-pi */
23 bool broadcast; /* requeue */
24 unsigned int runtime; /* seconds*/
25 unsigned int nthreads;
26 unsigned int nfutexes;
27 unsigned int nwakes;
28 unsigned int nrequeue;
29 int nbuckets;
30 };
31
32 /**
33 * futex_syscall() - SYS_futex syscall wrapper
34 * @uaddr: address of first futex
35 * @op: futex op code
36 * @val: typically expected value of uaddr, but varies by op
37 * @timeout: typically an absolute struct timespec (except where noted
38 * otherwise). Overloaded by some ops
39 * @uaddr2: address of second futex for some ops
40 * @val3: varies by op
41 * @opflags: flags to be bitwise OR'd with op, such as FUTEX_PRIVATE_FLAG
42 *
43 * futex_syscall() is used by all the following futex op wrappers. It can also be
44 * used for misuse and abuse testing. Generally, the specific op wrappers
45 * should be used instead.
46 *
47 * These argument descriptions are the defaults for all
48 * like-named arguments in the following wrappers except where noted below.
49 */
50 static inline int
futex_syscall(volatile u_int32_t * uaddr,int op,u_int32_t val,struct timespec * timeout,volatile u_int32_t * uaddr2,int val3,int opflags)51 futex_syscall(volatile u_int32_t *uaddr, int op, u_int32_t val, struct timespec *timeout,
52 volatile u_int32_t *uaddr2, int val3, int opflags)
53 {
54 return syscall(SYS_futex, uaddr, op | opflags, val, timeout, uaddr2, val3);
55 }
56
57 static inline int
futex_syscall_nr_requeue(volatile u_int32_t * uaddr,int op,u_int32_t val,int nr_requeue,volatile u_int32_t * uaddr2,int val3,int opflags)58 futex_syscall_nr_requeue(volatile u_int32_t *uaddr, int op, u_int32_t val, int nr_requeue,
59 volatile u_int32_t *uaddr2, int val3, int opflags)
60 {
61 return syscall(SYS_futex, uaddr, op | opflags, val, nr_requeue, uaddr2, val3);
62 }
63
64 /**
65 * futex_wait() - block on uaddr with optional timeout
66 * @timeout: relative timeout
67 */
68 static inline int
futex_wait(u_int32_t * uaddr,u_int32_t val,struct timespec * timeout,int opflags)69 futex_wait(u_int32_t *uaddr, u_int32_t val, struct timespec *timeout, int opflags)
70 {
71 return futex_syscall(uaddr, FUTEX_WAIT, val, timeout, NULL, 0, opflags);
72 }
73
74 /**
75 * futex_wake() - wake one or more tasks blocked on uaddr
76 * @nr_wake: wake up to this many tasks
77 */
78 static inline int
futex_wake(u_int32_t * uaddr,int nr_wake,int opflags)79 futex_wake(u_int32_t *uaddr, int nr_wake, int opflags)
80 {
81 return futex_syscall(uaddr, FUTEX_WAKE, nr_wake, NULL, NULL, 0, opflags);
82 }
83
84 /**
85 * futex_lock_pi() - block on uaddr as a PI mutex
86 */
87 static inline int
futex_lock_pi(u_int32_t * uaddr,struct timespec * timeout,int opflags)88 futex_lock_pi(u_int32_t *uaddr, struct timespec *timeout, int opflags)
89 {
90 return futex_syscall(uaddr, FUTEX_LOCK_PI, 0, timeout, NULL, 0, opflags);
91 }
92
93 /**
94 * futex_unlock_pi() - release uaddr as a PI mutex, waking the top waiter
95 */
96 static inline int
futex_unlock_pi(u_int32_t * uaddr,int opflags)97 futex_unlock_pi(u_int32_t *uaddr, int opflags)
98 {
99 return futex_syscall(uaddr, FUTEX_UNLOCK_PI, 0, NULL, NULL, 0, opflags);
100 }
101
102 /**
103 * futex_cmp_requeue() - requeue tasks from uaddr to uaddr2
104 * @nr_wake: wake up to this many tasks
105 * @nr_requeue: requeue up to this many tasks
106 */
107 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)108 futex_cmp_requeue(u_int32_t *uaddr, u_int32_t val, u_int32_t *uaddr2, int nr_wake,
109 int nr_requeue, int opflags)
110 {
111 return futex_syscall_nr_requeue(uaddr, FUTEX_CMP_REQUEUE, nr_wake, nr_requeue, uaddr2,
112 val, opflags);
113 }
114
115 /**
116 * futex_wait_requeue_pi() - block on uaddr and prepare to requeue to uaddr2
117 * @uaddr: non-PI futex source
118 * @uaddr2: PI futex target
119 *
120 * This is the first half of the requeue_pi mechanism. It shall always be
121 * paired with futex_cmp_requeue_pi().
122 */
123 static inline int
futex_wait_requeue_pi(u_int32_t * uaddr,u_int32_t val,u_int32_t * uaddr2,struct timespec * timeout,int opflags)124 futex_wait_requeue_pi(u_int32_t *uaddr, u_int32_t val, u_int32_t *uaddr2,
125 struct timespec *timeout, int opflags)
126 {
127 return futex_syscall(uaddr, FUTEX_WAIT_REQUEUE_PI, val, timeout, uaddr2, 0,
128 opflags);
129 }
130
131 /**
132 * futex_cmp_requeue_pi() - requeue tasks from uaddr to uaddr2
133 * @uaddr: non-PI futex source
134 * @uaddr2: PI futex target
135 * @nr_requeue: requeue up to this many tasks
136 *
137 * This is the second half of the requeue_pi mechanism. It shall always be
138 * paired with futex_wait_requeue_pi(). The first waker is always awoken.
139 */
140 static inline int
futex_cmp_requeue_pi(u_int32_t * uaddr,u_int32_t val,u_int32_t * uaddr2,int nr_requeue,int opflags)141 futex_cmp_requeue_pi(u_int32_t *uaddr, u_int32_t val, u_int32_t *uaddr2,
142 int nr_requeue, int opflags)
143 {
144 return futex_syscall_nr_requeue(uaddr, FUTEX_CMP_REQUEUE_PI, 1, nr_requeue, uaddr2,
145 val, opflags);
146 }
147
148 void futex_set_nbuckets_param(struct bench_futex_parameters *params);
149 void futex_print_nbuckets(struct bench_futex_parameters *params);
150
151 #endif /* _FUTEX_H */
152