1/*
2 * Wrappers around Linux futex syscall
3 *
4 * Copyright Red Hat, Inc. 2017
5 *
6 * Author:
7 * Paolo Bonzini <pbonzini@redhat.com>
8 *
9 * This work is licensed under the terms of the GNU GPL, version 2 or later.
10 * See the COPYING file in the top-level directory.
11 *
12 */
13
14#ifndef QEMU_FUTEX_H
15#define QEMU_FUTEX_H
16
17#include <sys/syscall.h>
18#include <linux/futex.h>
19
20#define qemu_futex(...) syscall(__NR_futex, __VA_ARGS__)
21
22static inline void qemu_futex_wake(void *f, int n)
23{
24 qemu_futex(f, FUTEX_WAKE, n, NULL, NULL, 0);
25}
26
27static inline void qemu_futex_wait(void *f, unsigned val)
28{
29 while (qemu_futex(f, FUTEX_WAIT, (int) val, NULL, NULL, 0)) {
30 switch (errno) {
31 case EWOULDBLOCK:
32 return;
33 case EINTR:
34 break; /* get out of switch and retry */
35 default:
36 abort();
37 }
38 }
39}
40
41#endif /* QEMU_FUTEX_H */
42