[1/9,v2,BZ,16892] Add linux-generic lowlevellock.h
Commit Message
Thanks both for the review. I've made those changes, updated patch follows.
To my surprise the code was not quite identical so I re-ran the nptl tests on arm. Still no regressions - I see nptl/tst-cond21 failing intermittently but it looks like it's timing sensitive and I don't see how this change could cause a problem here.
OK?
2014-06-09 Bernard Ogden <bernie.ogden@linaro.org>
[BZ #16892]
* sysdeps/unix/sysv/linux/lowlevellock.h: New file.
On 11 Jun 2014, at 19:47, Richard Henderson <rth@twiddle.net> wrote:
> Many instances of:
>
>> + if(INTERNAL_SYSCALL_ERROR_P (__ret, __err)) \
>
> Missed space after IF.
>
>> + __ret = -(INTERNAL_SYSCALL_ERRNO (__ret, __err)); \
>
> Silly extra parenthesis around INTERNAL_SYSCALL_ERRNO.
>
>
> r~
Comments
Looks OK to me.
On 6/12/2014 5:41 PM, Bernard Ogden wrote:
> Thanks both for the review. I've made those changes, updated patch follows.
>
> To my surprise the code was not quite identical so I re-ran the nptl tests on arm. Still no regressions - I see nptl/tst-cond21 failing intermittently but it looks like it's timing sensitive and I don't see how this change could cause a problem here.
>
> OK?
>
>
> 2014-06-09 Bernard Ogden <bernie.ogden@linaro.org>
>
> [BZ #16892]
> * sysdeps/unix/sysv/linux/lowlevellock.h: New file.
>
>
> diff --git a/sysdeps/unix/sysv/linux/lowlevellock.h b/sysdeps/unix/sysv/linux/lowlevellock.h
> new file mode 100644
> index 0000000..efba7a7
> --- /dev/null
> +++ b/sysdeps/unix/sysv/linux/lowlevellock.h
> @@ -0,0 +1,313 @@
> +/* Copyright (C) 2011-2014 Free Software Foundation, Inc.
> + This file is part of the GNU C Library.
> + Contributed by Chris Metcalf <cmetcalf@tilera.com>, 2011.
> +
> + The GNU C Library is free software; you can redistribute it and/or
> + modify it under the terms of the GNU Lesser General Public
> + License as published by the Free Software Foundation; either
> + version 2.1 of the License, or (at your option) any later version.
> +
> + The GNU C Library is distributed in the hope that it will be useful,
> + but WITHOUT ANY WARRANTY; without even the implied warranty of
> + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
> + Lesser General Public License for more details.
> +
> + You should have received a copy of the GNU Lesser General Public
> + License along with the GNU C Library. If not, see
> + <http://www.gnu.org/licenses/>. */
> +
> +#ifndef _LOWLEVELLOCK_H
> +#define _LOWLEVELLOCK_H 1
> +
> +#include <time.h>
> +#include <sys/param.h>
> +#include <bits/pthreadtypes.h>
> +#include <atomic.h>
> +#include <sysdep.h>
> +#include <kernel-features.h>
> +
> +
> +#define FUTEX_WAIT 0
> +#define FUTEX_WAKE 1
> +#define FUTEX_REQUEUE 3
> +#define FUTEX_CMP_REQUEUE 4
> +#define FUTEX_WAKE_OP 5
> +#define FUTEX_OP_CLEAR_WAKE_IF_GT_ONE ((4 << 24) | 1)
> +#define FUTEX_LOCK_PI 6
> +#define FUTEX_UNLOCK_PI 7
> +#define FUTEX_TRYLOCK_PI 8
> +#define FUTEX_WAIT_BITSET 9
> +#define FUTEX_WAKE_BITSET 10
> +#define FUTEX_WAIT_REQUEUE_PI 11
> +#define FUTEX_CMP_REQUEUE_PI 12
> +#define FUTEX_PRIVATE_FLAG 128
> +#define FUTEX_CLOCK_REALTIME 256
> +
> +#define FUTEX_BITSET_MATCH_ANY 0xffffffff
> +
> +/* Values for 'private' parameter of locking macros. Yes, the
> + definition seems to be backwards. But it is not. The bit will be
> + reversed before passing to the system call. */
> +#define LLL_PRIVATE 0
> +#define LLL_SHARED FUTEX_PRIVATE_FLAG
> +
> +
> +#if !defined NOT_IN_libc || defined IS_IN_rtld
> +/* In libc.so or ld.so all futexes are private. */
> +# ifdef __ASSUME_PRIVATE_FUTEX
> +# define __lll_private_flag(fl, private) \
> + ((fl) | FUTEX_PRIVATE_FLAG)
> +# else
> +# define __lll_private_flag(fl, private) \
> + ((fl) | THREAD_GETMEM (THREAD_SELF, header.private_futex))
> +# endif
> +#else
> +# ifdef __ASSUME_PRIVATE_FUTEX
> +# define __lll_private_flag(fl, private) \
> + (((fl) | FUTEX_PRIVATE_FLAG) ^ (private))
> +# else
> +# define __lll_private_flag(fl, private) \
> + (__builtin_constant_p (private) \
> + ? ((private) == 0 \
> + ? ((fl) | THREAD_GETMEM (THREAD_SELF, header.private_futex)) \
> + : (fl)) \
> + : ((fl) | (((private) ^ FUTEX_PRIVATE_FLAG) \
> + & THREAD_GETMEM (THREAD_SELF, header.private_futex))))
> +# endif
> +#endif
> +
> +#define INLINE_FUTEX_SYSCALL(nr, args...) \
> + ({ \
> + INTERNAL_SYSCALL_DECL (__err); \
> + long int __ret = INTERNAL_SYSCALL (futex, __err, nr, args); \
> + if (__glibc_unlikely (INTERNAL_SYSCALL_ERROR_P (__ret, __err))) \
> + __ret = -INTERNAL_SYSCALL_ERRNO (__ret, __err); \
> + __ret; \
> + })
> +
> +#define lll_futex_wait(futexp, val, private) \
> + lll_futex_timed_wait (futexp, val, NULL, private)
> +
> +#define lll_futex_timed_wait(futexp, val, timespec, private) \
> + ({ \
> + INLINE_FUTEX_SYSCALL (4, (futexp), \
> + __lll_private_flag (FUTEX_WAIT, private), \
> + (val), (timespec)); \
> + })
> +
> +#define lll_futex_timed_wait_bitset(futexp, val, timespec, clockbit, private) \
> + ({ \
> + int __op = FUTEX_WAIT_BITSET | clockbit; \
> + INLINE_FUTEX_SYSCALL (6, (futexp), \
> + __lll_private_flag (__op, private), \
> + (val), (timespec), NULL /* Unused. */, \
> + FUTEX_BITSET_MATCH_ANY); \
> + })
> +
> +#define lll_futex_wake(futexp, nr, private) \
> + ({ \
> + INLINE_FUTEX_SYSCALL (4, (futexp), \
> + __lll_private_flag (FUTEX_WAKE, private), \
> + (nr), 0); \
> + })
> +
> +#define lll_robust_dead(futexv, private) \
> + do \
> + { \
> + int *__futexp = &(futexv); \
> + atomic_or (__futexp, FUTEX_OWNER_DIED); \
> + lll_futex_wake (__futexp, 1, private); \
> + } \
> + while (0)
> +
> +/* Returns non-zero if error happened, zero if success. */
> +#define lll_futex_requeue(futexp, nr_wake, nr_move, mutex, val, private) \
> + ({ \
> + INLINE_FUTEX_SYSCALL (6, (futexp), \
> + __lll_private_flag (FUTEX_CMP_REQUEUE, private), \
> + (nr_wake), (nr_move), (mutex), (val)); \
> + })
> +
> +/* Returns non-zero if error happened, zero if success. */
> +#define lll_futex_wake_unlock(futexp, nr_wake, nr_wake2, futexp2, private) \
> + ({ \
> + INLINE_FUTEX_SYSCALL (6, (futexp), \
> + __lll_private_flag (FUTEX_WAKE_OP, private), \
> + (nr_wake), (nr_wake2), (futexp2), \
> + FUTEX_OP_CLEAR_WAKE_IF_GT_ONE); \
> + })
> +
> +/* Priority Inheritance support. */
> +#define lll_futex_wait_requeue_pi(futexp, val, mutex, private) \
> + lll_futex_timed_wait_requeue_pi (futexp, val, NULL, 0, mutex, private)
> +
> +#define lll_futex_timed_wait_requeue_pi(futexp, val, timespec, clockbit, \
> + mutex, private) \
> + ({ \
> + int __op = FUTEX_WAIT_REQUEUE_PI | clockbit; \
> + INLINE_FUTEX_SYSCALL (5, (futexp), \
> + __lll_private_flag (__op, private), \
> + (val), (timespec), mutex); \
> + })
> +
> +#define lll_futex_cmp_requeue_pi(futexp, nr_wake, nr_move, mutex, val, priv) \
> + ({ \
> + INLINE_FUTEX_SYSCALL (6, (futexp), \
> + __lll_private_flag (FUTEX_CMP_REQUEUE_PI, priv), \
> + (nr_wake), (nr_move), (mutex), (val)); \
> + })
> +
> +
> +static inline int __attribute__ ((always_inline))
> +__lll_trylock (int *futex)
> +{
> + return atomic_compare_and_exchange_bool_acq (futex, 1, 0);
> +}
> +#define lll_trylock(lock) __lll_trylock (&(lock))
> +
> +
> +static inline int __attribute__ ((always_inline))
> +__lll_cond_trylock (int *futex)
> +{
> + return atomic_compare_and_exchange_bool_acq (futex, 2, 0);
> +}
> +#define lll_cond_trylock(lock) __lll_cond_trylock (&(lock))
> +
> +
> +static inline int __attribute__ ((always_inline))
> +__lll_robust_trylock (int *futex, int id)
> +{
> + return atomic_compare_and_exchange_bool_acq (futex, id, 0);
> +}
> +#define lll_robust_trylock(lock, id) \
> + __lll_robust_trylock (&(lock), id)
> +
> +extern void __lll_lock_wait_private (int *futex) attribute_hidden;
> +extern void __lll_lock_wait (int *futex, int private) attribute_hidden;
> +extern int __lll_robust_lock_wait (int *futex, int private) attribute_hidden;
> +
> +static inline void __attribute__ ((always_inline))
> +__lll_lock (int *futex, int private)
> +{
> + if (atomic_compare_and_exchange_bool_acq (futex, 1, 0) != 0)
> + {
> + if (__builtin_constant_p (private) && private == LLL_PRIVATE)
> + __lll_lock_wait_private (futex);
> + else
> + __lll_lock_wait (futex, private);
> + }
> +}
> +#define lll_lock(futex, private) __lll_lock (&(futex), private)
> +
> +
> +static inline int __attribute__ ((always_inline))
> +__lll_robust_lock (int *futex, int id, int private)
> +{
> + int result = 0;
> + if (atomic_compare_and_exchange_bool_acq (futex, id, 0) != 0)
> + result = __lll_robust_lock_wait (futex, private);
> + return result;
> +}
> +#define lll_robust_lock(futex, id, private) \
> + __lll_robust_lock (&(futex), id, private)
> +
> +
> +static inline void __attribute__ ((always_inline))
> +__lll_cond_lock (int *futex, int private)
> +{
> + if (atomic_compare_and_exchange_bool_acq (futex, 2, 0) != 0)
> + __lll_lock_wait (futex, private);
> +}
> +#define lll_cond_lock(futex, private) __lll_cond_lock (&(futex), private)
> +
> +
> +#define lll_robust_cond_lock(futex, id, private) \
> + __lll_robust_lock (&(futex), (id) | FUTEX_WAITERS, private)
> +
> +
> +extern int __lll_timedlock_wait (int *futex, const struct timespec *,
> + int private) attribute_hidden;
> +extern int __lll_robust_timedlock_wait (int *futex, const struct timespec *,
> + int private) attribute_hidden;
> +
> +static inline int __attribute__ ((always_inline))
> +__lll_timedlock (int *futex, const struct timespec *abstime, int private)
> +{
> + int result = 0;
> + if (atomic_compare_and_exchange_bool_acq (futex, 1, 0) != 0)
> + result = __lll_timedlock_wait (futex, abstime, private);
> + return result;
> +}
> +#define lll_timedlock(futex, abstime, private) \
> + __lll_timedlock (&(futex), abstime, private)
> +
> +
> +static inline int __attribute__ ((always_inline))
> +__lll_robust_timedlock (int *futex, const struct timespec *abstime,
> + int id, int private)
> +{
> + int result = 0;
> + if (atomic_compare_and_exchange_bool_acq (futex, id, 0) != 0)
> + result = __lll_robust_timedlock_wait (futex, abstime, private);
> + return result;
> +}
> +#define lll_robust_timedlock(futex, abstime, id, private) \
> + __lll_robust_timedlock (&(futex), abstime, id, private)
> +
> +
> +#define __lll_unlock(futex, private) \
> + (void) \
> + ({ int *__futex = (futex); \
> + int __oldval = atomic_exchange_rel (__futex, 0); \
> + if (__glibc_unlikely (__oldval > 1)) \
> + lll_futex_wake (__futex, 1, private); \
> + })
> +#define lll_unlock(futex, private) __lll_unlock(&(futex), private)
> +
> +
> +#define __lll_robust_unlock(futex, private) \
> + (void) \
> + ({ int *__futex = (futex); \
> + int __oldval = atomic_exchange_rel (__futex, 0); \
> + if (__glibc_unlikely (__oldval & FUTEX_WAITERS)) \
> + lll_futex_wake (__futex, 1, private); \
> + })
> +#define lll_robust_unlock(futex, private) \
> + __lll_robust_unlock(&(futex), private)
> +
> +
> +#define lll_islocked(futex) \
> + (futex != 0)
> +
> +/* Initializers for lock. */
> +#define LLL_LOCK_INITIALIZER (0)
> +#define LLL_LOCK_INITIALIZER_LOCKED (1)
> +
> +/* The states of a lock are:
> + 0 - untaken
> + 1 - taken by one user
> + >1 - taken by more users */
> +
> +/* The kernel notifies a process which uses CLONE_CHILD_CLEARTID via futex
> + wakeup when the clone terminates. The memory location contains the
> + thread ID while the clone is running and is reset to zero
> + afterwards. */
> +#define lll_wait_tid(tid) \
> + do { \
> + __typeof (tid) __tid; \
> + while ((__tid = (tid)) != 0) \
> + lll_futex_wait (&(tid), __tid, LLL_SHARED); \
> + } while (0)
> +
> +extern int __lll_timedwait_tid (int *, const struct timespec *)
> + attribute_hidden;
> +
> +#define lll_timedwait_tid(tid, abstime) \
> + ({ \
> + int __res = 0; \
> + if ((tid) != 0) \
> + __res = __lll_timedwait_tid (&(tid), (abstime)); \
> + __res; \
> + })
> +
> +#endif /* lowlevellock.h */
>
>
>
> On 11 Jun 2014, at 19:47, Richard Henderson <rth@twiddle.net> wrote:
>
>> Many instances of:
>>
>>> + if(INTERNAL_SYSCALL_ERROR_P (__ret, __err)) \
>> Missed space after IF.
>>
>>> + __ret = -(INTERNAL_SYSCALL_ERRNO (__ret, __err)); \
>> Silly extra parenthesis around INTERNAL_SYSCALL_ERRNO.
>>
>>
>> r~
Bernard Ogden <bernie.ogden@linaro.org> writes:
> +static inline int __attribute__ ((always_inline))
> +__lll_trylock (int *futex)
> +{
> + return atomic_compare_and_exchange_bool_acq (futex, 1, 0);
> +}
You cannot use inlines here, it breaks coldfire:
In file included from ../sysdeps/unix/sysv/linux/m68k/coldfire/sysdep.h:21:0,
from x.c:1:
../sysdeps/unix/sysv/linux/lowlevellock.h: In function ‘__lll_trylock’:
../sysdeps/unix/sysdep.h:34:31: error: ‘SYS_atomic_cmpxchg_32’ undeclared (first use in this function)
#define SYS_ify(syscall_name) SYS_##syscall_name
^
../sysdeps/unix/sysv/linux/m68k/coldfire/nptl/bits/atomic.h:74:29: note: in expansion of macro ‘SYS_ify’
= (__typeof (oldval)) SYS_ify (atomic_cmpxchg_32); \
^
../include/atomic.h:138:6: note: in expansion of macro ‘atomic_compare_and_exchange_val_acq’
atomic_compare_and_exchange_val_acq (mem, newval, __atg3_old) \
^
../sysdeps/unix/sysv/linux/lowlevellock.h:186:10: note: in expansion of macro ‘atomic_compare_and_exchange_bool_acq’
return atomic_compare_and_exchange_bool_acq (futex, 1, 0);
^
../sysdeps/unix/sysdep.h:34:31: note: each undeclared identifier is reported only once for each function it appears in
#define SYS_ify(syscall_name) SYS_##syscall_name
^
../sysdeps/unix/sysv/linux/m68k/coldfire/nptl/bits/atomic.h:74:29: note: in expansion of macro ‘SYS_ify’
= (__typeof (oldval)) SYS_ify (atomic_cmpxchg_32); \
^
../include/atomic.h:138:6: note: in expansion of macro ‘atomic_compare_and_exchange_val_acq’
atomic_compare_and_exchange_val_acq (mem, newval, __atg3_old) \
^
../sysdeps/unix/sysv/linux/lowlevellock.h:186:10: note: in expansion of macro ‘atomic_compare_and_exchange_bool_acq’
return atomic_compare_and_exchange_bool_acq (futex, 1, 0);
^
Andreas.
new file mode 100644
@@ -0,0 +1,313 @@
+/* Copyright (C) 2011-2014 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+ Contributed by Chris Metcalf <cmetcalf@tilera.com>, 2011.
+
+ The GNU C Library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU Lesser General Public
+ License as published by the Free Software Foundation; either
+ version 2.1 of the License, or (at your option) any later version.
+
+ The GNU C Library is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public
+ License along with the GNU C Library. If not, see
+ <http://www.gnu.org/licenses/>. */
+
+#ifndef _LOWLEVELLOCK_H
+#define _LOWLEVELLOCK_H 1
+
+#include <time.h>
+#include <sys/param.h>
+#include <bits/pthreadtypes.h>
+#include <atomic.h>
+#include <sysdep.h>
+#include <kernel-features.h>
+
+
+#define FUTEX_WAIT 0
+#define FUTEX_WAKE 1
+#define FUTEX_REQUEUE 3
+#define FUTEX_CMP_REQUEUE 4
+#define FUTEX_WAKE_OP 5
+#define FUTEX_OP_CLEAR_WAKE_IF_GT_ONE ((4 << 24) | 1)
+#define FUTEX_LOCK_PI 6
+#define FUTEX_UNLOCK_PI 7
+#define FUTEX_TRYLOCK_PI 8
+#define FUTEX_WAIT_BITSET 9
+#define FUTEX_WAKE_BITSET 10
+#define FUTEX_WAIT_REQUEUE_PI 11
+#define FUTEX_CMP_REQUEUE_PI 12
+#define FUTEX_PRIVATE_FLAG 128
+#define FUTEX_CLOCK_REALTIME 256
+
+#define FUTEX_BITSET_MATCH_ANY 0xffffffff
+
+/* Values for 'private' parameter of locking macros. Yes, the
+ definition seems to be backwards. But it is not. The bit will be
+ reversed before passing to the system call. */
+#define LLL_PRIVATE 0
+#define LLL_SHARED FUTEX_PRIVATE_FLAG
+
+
+#if !defined NOT_IN_libc || defined IS_IN_rtld
+/* In libc.so or ld.so all futexes are private. */
+# ifdef __ASSUME_PRIVATE_FUTEX
+# define __lll_private_flag(fl, private) \
+ ((fl) | FUTEX_PRIVATE_FLAG)
+# else
+# define __lll_private_flag(fl, private) \
+ ((fl) | THREAD_GETMEM (THREAD_SELF, header.private_futex))
+# endif
+#else
+# ifdef __ASSUME_PRIVATE_FUTEX
+# define __lll_private_flag(fl, private) \
+ (((fl) | FUTEX_PRIVATE_FLAG) ^ (private))
+# else
+# define __lll_private_flag(fl, private) \
+ (__builtin_constant_p (private) \
+ ? ((private) == 0 \
+ ? ((fl) | THREAD_GETMEM (THREAD_SELF, header.private_futex)) \
+ : (fl)) \
+ : ((fl) | (((private) ^ FUTEX_PRIVATE_FLAG) \
+ & THREAD_GETMEM (THREAD_SELF, header.private_futex))))
+# endif
+#endif
+
+#define INLINE_FUTEX_SYSCALL(nr, args...) \
+ ({ \
+ INTERNAL_SYSCALL_DECL (__err); \
+ long int __ret = INTERNAL_SYSCALL (futex, __err, nr, args); \
+ if (__glibc_unlikely (INTERNAL_SYSCALL_ERROR_P (__ret, __err))) \
+ __ret = -INTERNAL_SYSCALL_ERRNO (__ret, __err); \
+ __ret; \
+ })
+
+#define lll_futex_wait(futexp, val, private) \
+ lll_futex_timed_wait (futexp, val, NULL, private)
+
+#define lll_futex_timed_wait(futexp, val, timespec, private) \
+ ({ \
+ INLINE_FUTEX_SYSCALL (4, (futexp), \
+ __lll_private_flag (FUTEX_WAIT, private), \
+ (val), (timespec)); \
+ })
+
+#define lll_futex_timed_wait_bitset(futexp, val, timespec, clockbit, private) \
+ ({ \
+ int __op = FUTEX_WAIT_BITSET | clockbit; \
+ INLINE_FUTEX_SYSCALL (6, (futexp), \
+ __lll_private_flag (__op, private), \
+ (val), (timespec), NULL /* Unused. */, \
+ FUTEX_BITSET_MATCH_ANY); \
+ })
+
+#define lll_futex_wake(futexp, nr, private) \
+ ({ \
+ INLINE_FUTEX_SYSCALL (4, (futexp), \
+ __lll_private_flag (FUTEX_WAKE, private), \
+ (nr), 0); \
+ })
+
+#define lll_robust_dead(futexv, private) \
+ do \
+ { \
+ int *__futexp = &(futexv); \
+ atomic_or (__futexp, FUTEX_OWNER_DIED); \
+ lll_futex_wake (__futexp, 1, private); \
+ } \
+ while (0)
+
+/* Returns non-zero if error happened, zero if success. */
+#define lll_futex_requeue(futexp, nr_wake, nr_move, mutex, val, private) \
+ ({ \
+ INLINE_FUTEX_SYSCALL (6, (futexp), \
+ __lll_private_flag (FUTEX_CMP_REQUEUE, private), \
+ (nr_wake), (nr_move), (mutex), (val)); \
+ })
+
+/* Returns non-zero if error happened, zero if success. */
+#define lll_futex_wake_unlock(futexp, nr_wake, nr_wake2, futexp2, private) \
+ ({ \
+ INLINE_FUTEX_SYSCALL (6, (futexp), \
+ __lll_private_flag (FUTEX_WAKE_OP, private), \
+ (nr_wake), (nr_wake2), (futexp2), \
+ FUTEX_OP_CLEAR_WAKE_IF_GT_ONE); \
+ })
+
+/* Priority Inheritance support. */
+#define lll_futex_wait_requeue_pi(futexp, val, mutex, private) \
+ lll_futex_timed_wait_requeue_pi (futexp, val, NULL, 0, mutex, private)
+
+#define lll_futex_timed_wait_requeue_pi(futexp, val, timespec, clockbit, \
+ mutex, private) \
+ ({ \
+ int __op = FUTEX_WAIT_REQUEUE_PI | clockbit; \
+ INLINE_FUTEX_SYSCALL (5, (futexp), \
+ __lll_private_flag (__op, private), \
+ (val), (timespec), mutex); \
+ })
+
+#define lll_futex_cmp_requeue_pi(futexp, nr_wake, nr_move, mutex, val, priv) \
+ ({ \
+ INLINE_FUTEX_SYSCALL (6, (futexp), \
+ __lll_private_flag (FUTEX_CMP_REQUEUE_PI, priv), \
+ (nr_wake), (nr_move), (mutex), (val)); \
+ })
+
+
+static inline int __attribute__ ((always_inline))
+__lll_trylock (int *futex)
+{
+ return atomic_compare_and_exchange_bool_acq (futex, 1, 0);
+}
+#define lll_trylock(lock) __lll_trylock (&(lock))
+
+
+static inline int __attribute__ ((always_inline))
+__lll_cond_trylock (int *futex)
+{
+ return atomic_compare_and_exchange_bool_acq (futex, 2, 0);
+}
+#define lll_cond_trylock(lock) __lll_cond_trylock (&(lock))
+
+
+static inline int __attribute__ ((always_inline))
+__lll_robust_trylock (int *futex, int id)
+{
+ return atomic_compare_and_exchange_bool_acq (futex, id, 0);
+}
+#define lll_robust_trylock(lock, id) \
+ __lll_robust_trylock (&(lock), id)
+
+extern void __lll_lock_wait_private (int *futex) attribute_hidden;
+extern void __lll_lock_wait (int *futex, int private) attribute_hidden;
+extern int __lll_robust_lock_wait (int *futex, int private) attribute_hidden;
+
+static inline void __attribute__ ((always_inline))
+__lll_lock (int *futex, int private)
+{
+ if (atomic_compare_and_exchange_bool_acq (futex, 1, 0) != 0)
+ {
+ if (__builtin_constant_p (private) && private == LLL_PRIVATE)
+ __lll_lock_wait_private (futex);
+ else
+ __lll_lock_wait (futex, private);
+ }
+}
+#define lll_lock(futex, private) __lll_lock (&(futex), private)
+
+
+static inline int __attribute__ ((always_inline))
+__lll_robust_lock (int *futex, int id, int private)
+{
+ int result = 0;
+ if (atomic_compare_and_exchange_bool_acq (futex, id, 0) != 0)
+ result = __lll_robust_lock_wait (futex, private);
+ return result;
+}
+#define lll_robust_lock(futex, id, private) \
+ __lll_robust_lock (&(futex), id, private)
+
+
+static inline void __attribute__ ((always_inline))
+__lll_cond_lock (int *futex, int private)
+{
+ if (atomic_compare_and_exchange_bool_acq (futex, 2, 0) != 0)
+ __lll_lock_wait (futex, private);
+}
+#define lll_cond_lock(futex, private) __lll_cond_lock (&(futex), private)
+
+
+#define lll_robust_cond_lock(futex, id, private) \
+ __lll_robust_lock (&(futex), (id) | FUTEX_WAITERS, private)
+
+
+extern int __lll_timedlock_wait (int *futex, const struct timespec *,
+ int private) attribute_hidden;
+extern int __lll_robust_timedlock_wait (int *futex, const struct timespec *,
+ int private) attribute_hidden;
+
+static inline int __attribute__ ((always_inline))
+__lll_timedlock (int *futex, const struct timespec *abstime, int private)
+{
+ int result = 0;
+ if (atomic_compare_and_exchange_bool_acq (futex, 1, 0) != 0)
+ result = __lll_timedlock_wait (futex, abstime, private);
+ return result;
+}
+#define lll_timedlock(futex, abstime, private) \
+ __lll_timedlock (&(futex), abstime, private)
+
+
+static inline int __attribute__ ((always_inline))
+__lll_robust_timedlock (int *futex, const struct timespec *abstime,
+ int id, int private)
+{
+ int result = 0;
+ if (atomic_compare_and_exchange_bool_acq (futex, id, 0) != 0)
+ result = __lll_robust_timedlock_wait (futex, abstime, private);
+ return result;
+}
+#define lll_robust_timedlock(futex, abstime, id, private) \
+ __lll_robust_timedlock (&(futex), abstime, id, private)
+
+
+#define __lll_unlock(futex, private) \
+ (void) \
+ ({ int *__futex = (futex); \
+ int __oldval = atomic_exchange_rel (__futex, 0); \
+ if (__glibc_unlikely (__oldval > 1)) \
+ lll_futex_wake (__futex, 1, private); \
+ })
+#define lll_unlock(futex, private) __lll_unlock(&(futex), private)
+
+
+#define __lll_robust_unlock(futex, private) \
+ (void) \
+ ({ int *__futex = (futex); \
+ int __oldval = atomic_exchange_rel (__futex, 0); \
+ if (__glibc_unlikely (__oldval & FUTEX_WAITERS)) \
+ lll_futex_wake (__futex, 1, private); \
+ })
+#define lll_robust_unlock(futex, private) \
+ __lll_robust_unlock(&(futex), private)
+
+
+#define lll_islocked(futex) \
+ (futex != 0)
+
+/* Initializers for lock. */
+#define LLL_LOCK_INITIALIZER (0)
+#define LLL_LOCK_INITIALIZER_LOCKED (1)
+
+/* The states of a lock are:
+ 0 - untaken
+ 1 - taken by one user
+ >1 - taken by more users */
+
+/* The kernel notifies a process which uses CLONE_CHILD_CLEARTID via futex
+ wakeup when the clone terminates. The memory location contains the
+ thread ID while the clone is running and is reset to zero
+ afterwards. */
+#define lll_wait_tid(tid) \
+ do { \
+ __typeof (tid) __tid; \
+ while ((__tid = (tid)) != 0) \
+ lll_futex_wait (&(tid), __tid, LLL_SHARED); \
+ } while (0)
+
+extern int __lll_timedwait_tid (int *, const struct timespec *)
+ attribute_hidden;
+
+#define lll_timedwait_tid(tid, abstime) \
+ ({ \
+ int __res = 0; \
+ if ((tid) != 0) \
+ __res = __lll_timedwait_tid (&(tid), (abstime)); \
+ __res; \
+ })
+
+#endif /* lowlevellock.h */