1 /* Copyright (C) 2003-2022 Free Software Foundation, Inc.
2 This file is part of the GNU C Library.
3
4 The GNU C Library is free software; you can redistribute it and/or
5 modify it under the terms of the GNU Lesser General Public
6 License as published by the Free Software Foundation; either
7 version 2.1 of the License, or (at your option) any later version.
8
9 The GNU C Library is distributed in the hope that it will be useful,
10 but WITHOUT ANY WARRANTY; without even the implied warranty of
11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 Lesser General Public License for more details.
13
14 You should have received a copy of the GNU Lesser General Public
15 License along with the GNU C Library; if not, see
16 <https://www.gnu.org/licenses/>. */
17
18 #include "pthreadP.h"
19 #include <shlib-compat.h>
20
21 int
__pthread_spin_lock(pthread_spinlock_t * lock)22 __pthread_spin_lock (pthread_spinlock_t *lock)
23 {
24 int *p = (int *) lock;
25
26 while (__builtin_expect (__sync_val_compare_and_swap (p, 0, 1), 0))
27 {
28 /* Spin without using the atomic instruction. */
29 do
30 __asm __volatile ("hint @pause" : : : "memory");
31 while (*p);
32 }
33 return 0;
34 }
35 versioned_symbol (libc, __pthread_spin_lock, pthread_spin_lock,
36 GLIBC_2_34);
37
38 #if OTHER_SHLIB_COMPAT (libpthread, GLIBC_2_2, GLIBC_2_34)
39 compat_symbol (libpthread, __pthread_spin_lock, pthread_spin_lock,
40 GLIBC_2_2);
41 #endif
42