[PATCH 3/6] Split sparc out of main Linux kernel-features.h.
[glibc.git] / nptl / lowlevelrobustlock.c
blob35258071cfcd61bc03b67e7e9853eb03fd9218c6
1 /* Copyright (C) 2006-2014 Free Software Foundation, Inc.
2 This file is part of the GNU C Library.
3 Contributed by Jakub Jelinek <jakub@redhat.com>, 2006.
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.
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.
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 <http://www.gnu.org/licenses/>. */
19 #include <errno.h>
20 #include <sysdep.h>
21 #include <lowlevellock.h>
22 #include <sys/time.h>
23 #include <pthreadP.h>
24 #include <kernel-features.h>
27 int
28 __lll_robust_lock_wait (int *futex, int private)
30 int oldval = *futex;
31 int tid = THREAD_GETMEM (THREAD_SELF, tid);
33 /* If the futex changed meanwhile try locking again. */
34 if (oldval == 0)
35 goto try;
39 if (__glibc_unlikely (oldval & FUTEX_OWNER_DIED))
40 return oldval;
42 int newval = oldval | FUTEX_WAITERS;
43 if (oldval != newval
44 && atomic_compare_and_exchange_bool_acq (futex, newval, oldval))
45 continue;
47 lll_futex_wait (futex, newval, private);
49 try:
52 while ((oldval = atomic_compare_and_exchange_val_acq (futex,
53 tid | FUTEX_WAITERS,
54 0)) != 0);
55 return 0;
59 int
60 __lll_robust_timedlock_wait (int *futex, const struct timespec *abstime,
61 int private)
63 /* Reject invalid timeouts. */
64 if (abstime->tv_nsec < 0 || abstime->tv_nsec >= 1000000000)
65 return EINVAL;
67 int tid = THREAD_GETMEM (THREAD_SELF, tid);
68 int oldval = *futex;
70 /* If the futex changed meanwhile try locking again. */
71 if (oldval == 0)
72 goto try;
74 /* Work around the fact that the kernel rejects negative timeout values
75 despite them being valid. */
76 if (__glibc_unlikely (abstime->tv_sec < 0))
77 return ETIMEDOUT;
81 #if (!defined __ASSUME_FUTEX_CLOCK_REALTIME \
82 || !defined lll_futex_timed_wait_bitset)
83 struct timeval tv;
84 struct timespec rt;
86 /* Get the current time. */
87 (void) __gettimeofday (&tv, NULL);
89 /* Compute relative timeout. */
90 rt.tv_sec = abstime->tv_sec - tv.tv_sec;
91 rt.tv_nsec = abstime->tv_nsec - tv.tv_usec * 1000;
92 if (rt.tv_nsec < 0)
94 rt.tv_nsec += 1000000000;
95 --rt.tv_sec;
98 /* Already timed out? */
99 if (rt.tv_sec < 0)
100 return ETIMEDOUT;
101 #endif
103 /* Wait. */
104 if (__glibc_unlikely (oldval & FUTEX_OWNER_DIED))
105 return oldval;
107 int newval = oldval | FUTEX_WAITERS;
108 if (oldval != newval
109 && atomic_compare_and_exchange_bool_acq (futex, newval, oldval))
110 continue;
112 #if (!defined __ASSUME_FUTEX_CLOCK_REALTIME \
113 || !defined lll_futex_timed_wait_bitset)
114 lll_futex_timed_wait (futex, newval, &rt, private);
115 #else
116 lll_futex_timed_wait_bitset (futex, newval, abstime,
117 FUTEX_CLOCK_REALTIME, private);
118 #endif
120 try:
123 while ((oldval = atomic_compare_and_exchange_val_acq (futex,
124 tid | FUTEX_WAITERS,
125 0)) != 0);
127 return 0;