1/*
 2 * Glibc independent futex library for testing kernel functionality.
 3 * Shamelessly stolen from Darren Hart <dvhltc@us.ibm.com>
 4 *    http://git.kernel.org/cgit/linux/kernel/git/dvhart/futextest.git/
 5 */
 6
 7#ifndef _FUTEX_H
 8#define _FUTEX_H
 9
10#include <unistd.h>
11#include <sys/syscall.h>
12#include <sys/types.h>
13#include <linux/futex.h>
14
15/**
16 * futex() - SYS_futex syscall wrapper
17 * @uaddr:	address of first futex
18 * @op:		futex op code
19 * @val:	typically expected value of uaddr, but varies by op
20 * @timeout:	typically an absolute struct timespec (except where noted
21 *		otherwise). Overloaded by some ops
22 * @uaddr2:	address of second futex for some ops\
23 * @val3:	varies by op
24 * @opflags:	flags to be bitwise OR'd with op, such as FUTEX_PRIVATE_FLAG
25 *
26 * futex() is used by all the following futex op wrappers. It can also be
27 * used for misuse and abuse testing. Generally, the specific op wrappers
28 * should be used instead. It is a macro instead of an static inline function as
29 * some of the types over overloaded (timeout is used for nr_requeue for
30 * example).
31 *
32 * These argument descriptions are the defaults for all
33 * like-named arguments in the following wrappers except where noted below.
34 */
35#define futex(uaddr, op, val, timeout, uaddr2, val3, opflags) \
36	syscall(SYS_futex, uaddr, op | opflags, val, timeout, uaddr2, val3)
37
38/**
39 * futex_wait() - block on uaddr with optional timeout
40 * @timeout:	relative timeout
41 */
42static inline int
43futex_wait(u_int32_t *uaddr, u_int32_t val, struct timespec *timeout, int opflags)
44{
45	return futex(uaddr, FUTEX_WAIT, val, timeout, NULL, 0, opflags);
46}
47
48/**
49 * futex_wake() - wake one or more tasks blocked on uaddr
50 * @nr_wake:	wake up to this many tasks
51 */
52static inline int
53futex_wake(u_int32_t *uaddr, int nr_wake, int opflags)
54{
55	return futex(uaddr, FUTEX_WAKE, nr_wake, NULL, NULL, 0, opflags);
56}
57
58/**
59* futex_cmp_requeue() - requeue tasks from uaddr to uaddr2
60* @nr_wake:        wake up to this many tasks
61* @nr_requeue:        requeue up to this many tasks
62*/
63static inline int
64futex_cmp_requeue(u_int32_t *uaddr, u_int32_t val, u_int32_t *uaddr2, int nr_wake,
65		 int nr_requeue, int opflags)
66{
67	return futex(uaddr, FUTEX_CMP_REQUEUE, nr_wake, nr_requeue, uaddr2,
68		 val, opflags);
69}
70
71#endif /* _FUTEX_H */