1 /* Copyright (C) 2003 Free Software Foundation, Inc.
2 This file is part of the GNU C Library.
3 Contributed by Paul Mackerras <paulus@au.ibm.com>, 2003.
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 Libr \ary; if not, write to the Free
17 Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
20 #ifndef _LOWLEVELLOCK_H
21 #define _LOWLEVELLOCK_H 1
24 #include <sys/param.h>
25 #include <bits/pthreadtypes.h>
29 #define __NR_futex 221
33 /* Initializer for compatibility lock. */
34 #define LLL_MUTEX_LOCK_INITIALIZER (0)
36 #define lll_futex_wait(futexp, val) \
38 INTERNAL_SYSCALL_DECL (__err); \
41 __ret = INTERNAL_SYSCALL (futex, __err, 4, \
42 (futexp), FUTEX_WAIT, (val), 0); \
43 INTERNAL_SYSCALL_ERROR_P (__ret, __err)? -__ret: 0; \
46 #define lll_futex_timed_wait(futexp, val, timespec) \
48 INTERNAL_SYSCALL_DECL (__err); \
51 __ret = INTERNAL_SYSCALL (futex, __err, 4, \
52 (futexp), FUTEX_WAIT, (val), (timespec)); \
53 INTERNAL_SYSCALL_ERROR_P (__ret, __err)? -__ret: 0; \
56 #define lll_futex_wake(futexp, nr) \
58 INTERNAL_SYSCALL_DECL (__err); \
61 __ret = INTERNAL_SYSCALL (futex, __err, 4, \
62 (futexp), FUTEX_WAKE, (nr), 0); \
63 INTERNAL_SYSCALL_ERROR_P (__ret, __err)? -__ret: 0; \
67 # define __lll_acq_instr ""
68 # define __lll_rel_instr ""
70 # define __lll_acq_instr "isync"
71 # define __lll_rel_instr "sync"
74 /* Set *futex to 1 if it is 0, atomically. Returns the old value */
75 #define __lll_trylock(futex) \
77 __asm __volatile ("1: lwarx %0,0,%2\n" \
82 "2: " __lll_acq_instr \
83 : "=&r" (__val), "=m" (*futex) \
84 : "r" (futex), "r" (1), "1" (*futex) \
89 #define lll_mutex_trylock(lock) __lll_trylock (&(lock))
92 extern void __lll_lock_wait (int *futex, int val) attribute_hidden;
94 #define lll_mutex_lock(lock) \
96 int *__futex = &(lock); \
97 int __val = atomic_exchange_and_add (__futex, 1); \
98 __asm __volatile (__lll_acq_instr ::: "memory"); \
99 if (__builtin_expect (__val != 0, 0)) \
100 __lll_lock_wait (__futex, __val); \
103 extern int __lll_timedlock_wait
104 (int *futex, int val, const struct timespec *) attribute_hidden;
106 #define lll_mutex_timedlock(lock, abstime) \
107 ({ int *__futex = &(lock); \
108 int __val = atomic_exchange_and_add (__futex, 1); \
109 __asm __volatile (__lll_acq_instr ::: "memory"); \
110 if (__builtin_expect (__val != 0, 0)) \
111 __val = __lll_timedlock_wait (__futex, __val, (abstime)); \
115 #define lll_mutex_unlock(lock) \
117 int *__futex = &(lock); \
118 int __val = atomic_exchange_rel (__futex, 0); \
119 if (__builtin_expect (__val > 1, 0)) \
120 lll_futex_wake (__futex, 1); \
123 #define lll_mutex_islocked(futex) \
127 /* Our internal lock implementation is identical to the binary-compatible
128 mutex implementation. */
130 /* Type for lock object. */
131 typedef int lll_lock_t;
133 /* Initializers for lock. */
134 #define LLL_LOCK_INITIALIZER (0)
135 #define LLL_LOCK_INITIALIZER_LOCKED (1)
137 extern int lll_unlock_wake_cb (int *__futex) attribute_hidden;
139 /* The states of a lock are:
141 1 - taken by one user
142 >1 - taken by more users */
144 #define lll_trylock(lock) lll_mutex_trylock (lock)
145 #define lll_lock(lock) lll_mutex_lock (lock)
146 #define lll_unlock(lock) lll_mutex_unlock (lock)
147 #define lll_islocked(lock) lll_mutex_islocked (lock)
149 /* The kernel notifies a process which uses CLONE_CLEARTID via futex
150 wakeup when the clone terminates. The memory location contains the
151 thread ID while the clone is running and is reset to zero
153 #define lll_wait_tid(tid) \
155 __typeof (tid) __tid; \
156 while ((__tid = (tid)) != 0) \
157 lll_futex_wait (&(tid), __tid); \
160 extern int __lll_timedwait_tid (int *, const struct timespec *)
163 #define lll_timedwait_tid(tid, abstime) \
167 __res = __lll_timedwait_tid (&(tid), (abstime)); \
172 /* Conditional variable handling. */
174 extern void __lll_cond_wait (pthread_cond_t *cond)
176 extern int __lll_cond_timedwait (pthread_cond_t *cond,
177 const struct timespec *abstime)
179 extern void __lll_cond_wake (pthread_cond_t *cond)
181 extern void __lll_cond_broadcast (pthread_cond_t *cond)
184 #define lll_cond_wait(cond) \
185 __lll_cond_wait (cond)
186 #define lll_cond_timedwait(cond, abstime) \
187 __lll_cond_timedwait (cond, abstime)
188 #define lll_cond_wake(cond) \
189 __lll_cond_wake (cond)
190 #define lll_cond_broadcast(cond) \
191 __lll_cond_broadcast (cond)
193 #endif /* lowlevellock.h */