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
qemu_futex_wake(void * f,int n)22 static inline void qemu_futex_wake(void *f, int n)
23 {
24 qemu_futex(f, FUTEX_WAKE, n, NULL, NULL, 0);
25 }
26
qemu_futex_wait(void * f,unsigned val)27 static 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