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
32 #define FUTEX_REQUEUE 3
34 /* Initializer for compatibility lock. */
35 #define LLL_MUTEX_LOCK_INITIALIZER (0)
37 #define lll_futex_wait(futexp, val) \
39 INTERNAL_SYSCALL_DECL (__err); \
42 __ret = INTERNAL_SYSCALL (futex, __err, 4, \
43 (futexp), FUTEX_WAIT, (val), 0); \
44 INTERNAL_SYSCALL_ERROR_P (__ret, __err) ? -__ret : __ret; \
47 #define lll_futex_timed_wait(futexp, val, timespec) \
49 INTERNAL_SYSCALL_DECL (__err); \
52 __ret = INTERNAL_SYSCALL (futex, __err, 4, \
53 (futexp), FUTEX_WAIT, (val), (timespec)); \
54 INTERNAL_SYSCALL_ERROR_P (__ret, __err) ? -__ret : __ret; \
57 #define lll_futex_wake(futexp, nr) \
59 INTERNAL_SYSCALL_DECL (__err); \
62 __ret = INTERNAL_SYSCALL (futex, __err, 4, \
63 (futexp), FUTEX_WAKE, (nr), 0); \
64 INTERNAL_SYSCALL_ERROR_P (__ret, __err) ? -__ret : __ret; \
67 #define lll_futex_requeue(futexp, nr_wake, nr_move, mutex) \
69 INTERNAL_SYSCALL_DECL (__err); \
72 __ret = INTERNAL_SYSCALL (futex, __err, 5, \
73 (futexp), FUTEX_REQUEUE, (nr_wake), (nr_move), \
75 INTERNAL_SYSCALL_ERROR_P (__ret, __err) ? -__ret : __ret; \
79 # define __lll_acq_instr ""
80 # define __lll_rel_instr ""
82 # define __lll_acq_instr "isync"
83 # define __lll_rel_instr "sync"
86 /* Set *futex to 1 if it is 0, atomically. Returns the old value */
87 #define __lll_trylock(futex) \
89 __asm __volatile ("1: lwarx %0,0,%2\n" \
94 "2: " __lll_acq_instr \
95 : "=&r" (__val), "=m" (*futex) \
96 : "r" (futex), "r" (1), "1" (*futex) \
101 #define lll_mutex_trylock(lock) __lll_trylock (&(lock))
104 extern void __lll_lock_wait (int *futex, int val) attribute_hidden;
106 #define lll_mutex_lock(lock) \
108 int *__futex = &(lock); \
109 int __val = atomic_exchange_and_add (__futex, 1); \
110 __asm __volatile (__lll_acq_instr ::: "memory"); \
111 if (__builtin_expect (__val != 0, 0)) \
112 __lll_lock_wait (__futex, __val); \
115 #define lll_mutex_cond_lock(lock) \
117 int *__futex = &(lock); \
118 int __val = atomic_exchange_and_add (__futex, 2); \
119 __asm __volatile (__lll_acq_instr ::: "memory"); \
120 if (__builtin_expect (__val != 0, 0)) \
121 /* Note, the val + 1 is kind of ugly here. __lll_lock_wait will add \
122 1 again. But we added 2 to the futex value so this is the right \
123 value which will be passed to the kernel. */ \
124 __lll_lock_wait (__futex, __val + 1); \
127 extern int __lll_timedlock_wait
128 (int *futex, int val, const struct timespec *) attribute_hidden;
130 #define lll_mutex_timedlock(lock, abstime) \
131 ({ int *__futex = &(lock); \
132 int __val = atomic_exchange_and_add (__futex, 1); \
133 __asm __volatile (__lll_acq_instr ::: "memory"); \
134 if (__builtin_expect (__val != 0, 0)) \
135 __val = __lll_timedlock_wait (__futex, __val, (abstime)); \
139 #define lll_mutex_unlock(lock) \
141 int *__futex = &(lock); \
142 int __val = atomic_exchange_rel (__futex, 0); \
143 if (__builtin_expect (__val > 1, 0)) \
144 lll_futex_wake (__futex, 1); \
147 #define lll_mutex_unlock_force(lock) \
149 int *__futex = &(lock); \
151 __asm __volatile (__lll_rel_instr ::: "memory"); \
152 lll_futex_wake (__futex, 1); \
155 #define lll_mutex_islocked(futex) \
159 /* Our internal lock implementation is identical to the binary-compatible
160 mutex implementation. */
162 /* Type for lock object. */
163 typedef int lll_lock_t;
165 /* Initializers for lock. */
166 #define LLL_LOCK_INITIALIZER (0)
167 #define LLL_LOCK_INITIALIZER_LOCKED (1)
169 extern int lll_unlock_wake_cb (int *__futex) attribute_hidden;
171 /* The states of a lock are:
173 1 - taken by one user
174 >1 - taken by more users */
176 #define lll_trylock(lock) lll_mutex_trylock (lock)
177 #define lll_lock(lock) lll_mutex_lock (lock)
178 #define lll_unlock(lock) lll_mutex_unlock (lock)
179 #define lll_islocked(lock) lll_mutex_islocked (lock)
181 /* The kernel notifies a process which uses CLONE_CLEARTID via futex
182 wakeup when the clone terminates. The memory location contains the
183 thread ID while the clone is running and is reset to zero
185 #define lll_wait_tid(tid) \
187 __typeof (tid) __tid; \
188 while ((__tid = (tid)) != 0) \
189 lll_futex_wait (&(tid), __tid); \
192 extern int __lll_timedwait_tid (int *, const struct timespec *)
195 #define lll_timedwait_tid(tid, abstime) \
199 __res = __lll_timedwait_tid (&(tid), (abstime)); \
204 /* Conditional variable handling. */
206 extern void __lll_cond_wait (pthread_cond_t *cond)
208 extern int __lll_cond_timedwait (pthread_cond_t *cond,
209 const struct timespec *abstime)
211 extern void __lll_cond_wake (pthread_cond_t *cond)
213 extern void __lll_cond_broadcast (pthread_cond_t *cond)
216 #define lll_cond_wait(cond) \
217 __lll_cond_wait (cond)
218 #define lll_cond_timedwait(cond, abstime) \
219 __lll_cond_timedwait (cond, abstime)
220 #define lll_cond_wake(cond) \
221 __lll_cond_wake (cond)
222 #define lll_cond_broadcast(cond) \
223 __lll_cond_broadcast (cond)
225 #endif /* lowlevellock.h */