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- /* Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008,
- 2009 Free Software Foundation, Inc.
- This file is part of the GNU C Library.
- 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 <bits/kernel-features.h>
- #if defined(__UCLIBC_USE_TIME64__)
- #include "internal/time64_helpers.h"
- #endif
- #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_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 lll_futex_wait(futexp, val, private) \
- lll_futex_timed_wait(futexp, val, NULL, private)
- #if defined(__UCLIBC_USE_TIME64__) && defined(__NR_futex_time64)
- #define lll_futex_timed_wait(futexp, val, timespec, private) \
- ({ \
- INTERNAL_SYSCALL_DECL (__err); \
- long int __ret attribute_unused; \
- __ret = INTERNAL_SYSCALL (futex_time64, __err, 4, (long) (futexp), \
- __lll_private_flag (FUTEX_WAIT, private), \
- (val), (TO_TS64_P(timespec))); \
- INTERNAL_SYSCALL_ERROR_P (__ret, __err) ? -__ret : __ret; \
- })
- #define lll_futex_wake(futexp, nr, private) \
- ({ \
- INTERNAL_SYSCALL_DECL (__err); \
- long int __ret attribute_unused; \
- __ret = INTERNAL_SYSCALL (futex_time64, __err, 4, (long) (futexp), \
- __lll_private_flag (FUTEX_WAKE, private), \
- (nr), 0); \
- INTERNAL_SYSCALL_ERROR_P (__ret, __err) ? -__ret : __ret; \
- })
- #else
- #define lll_futex_timed_wait(futexp, val, timespec, private) \
- ({ \
- INTERNAL_SYSCALL_DECL (__err); \
- long int __ret attribute_unused; \
- __ret = INTERNAL_SYSCALL (futex, __err, 4, (long) (futexp), \
- __lll_private_flag (FUTEX_WAIT, private), \
- (val), (timespec)); \
- INTERNAL_SYSCALL_ERROR_P (__ret, __err) ? -__ret : __ret; \
- })
- #define lll_futex_wake(futexp, nr, private) \
- ({ \
- INTERNAL_SYSCALL_DECL (__err); \
- long int __ret attribute_unused; \
- __ret = INTERNAL_SYSCALL (futex, __err, 4, (long) (futexp), \
- __lll_private_flag (FUTEX_WAKE, private), \
- (nr), 0); \
- INTERNAL_SYSCALL_ERROR_P (__ret, __err) ? -__ret : __ret; \
- })
- #endif
- #define lll_robust_dead(futexv, private) \
- do \
- { \
- int *__futexp = &(futexv); \
- atomic_or (__futexp, FUTEX_OWNER_DIED); \
- lll_futex_wake (__futexp, 1, private); \
- } \
- while (0)
- #if defined(__UCLIBC_USE_TIME64__) && defined(__NR_futex_time64)
- /* Returns non-zero if error happened, zero if success. */
- #define lll_futex_requeue(futexp, nr_wake, nr_move, mutex, val, private) \
- ({ \
- INTERNAL_SYSCALL_DECL (__err); \
- long int __ret attribute_unused; \
- __ret = INTERNAL_SYSCALL (futex_time64, __err, 6, (long) (futexp), \
- __lll_private_flag (FUTEX_CMP_REQUEUE, private),\
- (nr_wake), (nr_move), (mutex), (val)); \
- INTERNAL_SYSCALL_ERROR_P (__ret, __err); \
- })
- /* Returns non-zero if error happened, zero if success. */
- #define lll_futex_wake_unlock(futexp, nr_wake, nr_wake2, futexp2, private) \
- ({ \
- INTERNAL_SYSCALL_DECL (__err); \
- long int __ret attribute_unused; \
- \
- __ret = INTERNAL_SYSCALL (futex_time64, __err, 6, (futexp), \
- __lll_private_flag (FUTEX_WAKE_OP, private), \
- (nr_wake), (nr_wake2), (futexp2), \
- FUTEX_OP_CLEAR_WAKE_IF_GT_ONE); \
- INTERNAL_SYSCALL_ERROR_P (__ret, __err); \
- })
- #else
- /* Returns non-zero if error happened, zero if success. */
- #define lll_futex_requeue(futexp, nr_wake, nr_move, mutex, val, private) \
- ({ \
- INTERNAL_SYSCALL_DECL (__err); \
- long int __ret attribute_unused; \
- __ret = INTERNAL_SYSCALL (futex, __err, 6, (long) (futexp), \
- __lll_private_flag (FUTEX_CMP_REQUEUE, private),\
- (nr_wake), (nr_move), (mutex), (val)); \
- INTERNAL_SYSCALL_ERROR_P (__ret, __err); \
- })
- /* Returns non-zero if error happened, zero if success. */
- #define lll_futex_wake_unlock(futexp, nr_wake, nr_wake2, futexp2, private) \
- ({ \
- INTERNAL_SYSCALL_DECL (__err); \
- long int __ret attribute_unused; \
- \
- __ret = INTERNAL_SYSCALL (futex, __err, 6, (futexp), \
- __lll_private_flag (FUTEX_WAKE_OP, private), \
- (nr_wake), (nr_wake2), (futexp2), \
- FUTEX_OP_CLEAR_WAKE_IF_GT_ONE); \
- INTERNAL_SYSCALL_ERROR_P (__ret, __err); \
- })
- #endif
- static inline int __attribute__((always_inline))
- __lll_trylock(int *futex)
- {
- return atomic_compare_and_exchange_val_acq (futex, 1, 0) != 0;
- }
- #define lll_trylock(lock) __lll_trylock (&(lock))
- static inline int __attribute__((always_inline))
- __lll_cond_trylock(int *futex)
- {
- return atomic_compare_and_exchange_val_acq (futex, 2, 0) != 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_val_acq (futex, id, 0) != 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;
- #define __lll_lock(futex, private) \
- ((void) ({ \
- int *__futex = (futex); \
- if (__builtin_expect (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)
- #define __lll_robust_lock(futex, id, private) \
- ({ \
- int *__futex = (futex); \
- int __val = 0; \
- \
- if (__builtin_expect (atomic_compare_and_exchange_bool_acq (__futex, id, \
- 0), 0)) \
- __val = __lll_robust_lock_wait (__futex, private); \
- __val; \
- })
- #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 __val = atomic_exchange_rel (__futex, 0); \
- \
- if (__builtin_expect (__val > 1, 0)) \
- 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 __val = atomic_exchange_rel (__futex, 0); \
- \
- if (__builtin_expect (__val & FUTEX_WAITERS, 0)) \
- lll_futex_wake (__futex, 1, private); \
- }))
- #define lll_robust_unlock(futex, private) \
- __lll_robust_unlock(&(futex), private)
- #define lll_islocked(futex) \
- (futex != 0)
- /* Our internal lock implementation is identical to the binary-compatible
- mutex implementation. */
- /* 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_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 */
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