Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
tjh.dev
kernel
os
linux
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
17struct 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 */
50static inline int
51futex_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
57static inline int
58futex_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 */
68static inline int
69futex_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 */
78static inline int
79futex_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 */
87static inline int
88futex_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 */
96static inline int
97futex_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*/
107static inline int
108futex_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 */
123static inline int
124futex_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 */
140static inline int
141futex_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
148void futex_set_nbuckets_param(struct bench_futex_parameters *params);
149void futex_print_nbuckets(struct bench_futex_parameters *params);
150
151#endif /* _FUTEX_H */