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
16struct 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 */
48static inline int
49futex_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
55static inline int
56futex_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 */
66static inline int
67futex_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 */
76static inline int
77futex_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 */
85static inline int
86futex_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 */
94static inline int
95futex_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*/
105static inline int
106futex_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 */
121static inline int
122futex_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 */
138static inline int
139futex_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