1/* low level locking for pthread library. Generic futex-using version.
2 Copyright (C) 2003-2023 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
4
5 The GNU C Library is free software; you can redistribute it and/or
6 modify it under the terms of the GNU Lesser General Public
7 License as published by the Free Software Foundation; either
8 version 2.1 of the License, or (at your option) any later version.
9
10 The GNU C Library is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 Lesser General Public License for more details.
14
15 You should have received a copy of the GNU Lesser General Public
16 License along with the GNU C Library; if not, see
17 <https://www.gnu.org/licenses/>. */
18
19#include <sysdep.h>
20#include <futex-internal.h>
21#include <atomic.h>
22#include <stap-probe.h>
23
24void
25__lll_lock_wait_private (int *futex)
26{
27 if (atomic_load_relaxed (futex) == 2)
28 goto futex;
29
30 while (atomic_exchange_acquire (futex, 2) != 0)
31 {
32 futex:
33 LIBC_PROBE (lll_lock_wait_private, 1, futex);
34 futex_wait ((unsigned int *) futex, 2, LLL_PRIVATE); /* Wait if *futex == 2. */
35 }
36}
37libc_hidden_def (__lll_lock_wait_private)
38
39void
40__lll_lock_wait (int *futex, int private)
41{
42 if (atomic_load_relaxed (futex) == 2)
43 goto futex;
44
45 while (atomic_exchange_acquire (futex, 2) != 0)
46 {
47 futex:
48 LIBC_PROBE (lll_lock_wait, 1, futex);
49 futex_wait ((unsigned int *) futex, 2, private); /* Wait if *futex == 2. */
50 }
51}
52libc_hidden_def (__lll_lock_wait)
53
54void
55__lll_lock_wake_private (int *futex)
56{
57 lll_futex_wake (futex, 1, LLL_PRIVATE);
58}
59libc_hidden_def (__lll_lock_wake_private)
60
61void
62__lll_lock_wake (int *futex, int private)
63{
64 lll_futex_wake (futex, 1, private);
65}
66libc_hidden_def (__lll_lock_wake)
67
68#if ENABLE_ELISION_SUPPORT
69int __pthread_force_elision;
70libc_hidden_data_def (__pthread_force_elision)
71#endif
72