+++ /dev/null
-/* Copyright (C) 2003-2014 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 <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 lll_futex_wait(futexp, val, private) \
- lll_futex_timed_wait(futexp, val, NULL, private)
-
-#define lll_futex_timed_wait(futexp, val, timespec, private) \
- ({ \
- INTERNAL_SYSCALL_DECL (__err); \
- long int __ret; \
- __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_timed_wait_bitset(futexp, val, timespec, clockbit, private) \
- ({ \
- INTERNAL_SYSCALL_DECL (__err); \
- long int __ret; \
- int __op = FUTEX_WAIT_BITSET | clockbit; \
- __ret = INTERNAL_SYSCALL (futex, __err, 6, (long) (futexp), \
- __lll_private_flag (__op, private), \
- (val), (timespec), NULL /* Unused. */, \
- FUTEX_BITSET_MATCH_ANY); \
- INTERNAL_SYSCALL_ERROR_P (__ret, __err) ? -__ret : __ret; \
- })
-
-#define lll_futex_wake(futexp, nr, private) \
- ({ \
- INTERNAL_SYSCALL_DECL (__err); \
- long int __ret; \
- __ret = INTERNAL_SYSCALL (futex, __err, 4, (long) (futexp), \
- __lll_private_flag (FUTEX_WAKE, private), \
- (nr), 0); \
- INTERNAL_SYSCALL_ERROR_P (__ret, __err) ? -__ret : __ret; \
- })
-
-/* 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; \
- __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; \
- \
- __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); \
- })
-
-/* 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) \
- ({ \
- INTERNAL_SYSCALL_DECL (__err); \
- long int __ret; \
- int __op = FUTEX_WAIT_REQUEUE_PI | clockbit; \
- \
- __ret = INTERNAL_SYSCALL (futex, __err, 5, (futexp), \
- __lll_private_flag (__op, private), \
- (val), (timespec), mutex); \
- INTERNAL_SYSCALL_ERROR_P (__ret, __err) ? -__ret : __ret; \
- })
-
-#define lll_futex_cmp_requeue_pi(futexp, nr_wake, nr_move, mutex, val, priv) \
- ({ \
- INTERNAL_SYSCALL_DECL (__err); \
- long int __ret; \
- \
- __ret = INTERNAL_SYSCALL (futex, __err, 6, (futexp), \
- __lll_private_flag (FUTEX_CMP_REQUEUE_PI, priv),\
- (nr_wake), (nr_move), (mutex), (val)); \
- INTERNAL_SYSCALL_ERROR_P (__ret, __err); \
- })
-
-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))
-
-
-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_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; \
- })
-
-/* Implement __libc_lock_lock using exchange_and_add, which expands into
- a single instruction on XLP processors. We enable this for all MIPS
- processors as atomic_exchange_and_add_acq and
- atomic_compare_and_exchange_acq take the same time to execute.
- This is a simplified expansion of ({ lll_lock (NAME, LLL_PRIVATE); 0; }).
-
- Note: __lll_lock_wait_private() resets lock value to '2', which prevents
- unbounded increase of the lock value and [with billions of threads]
- overflow. */
-#define __libc_lock_lock(NAME) \
- ({ \
- int *__futex = &(NAME); \
- if (__builtin_expect (atomic_exchange_and_add_acq (__futex, 1), 0)) \
- __lll_lock_wait_private (__futex); \
- 0; \
- })
-
-#ifdef _MIPS_ARCH_XLP
-/* The generic version using a single atomic_compare_and_exchange_acq takes
- less time for non-XLP processors, so we use below for XLP only. */
-# define __libc_lock_trylock(NAME) \
- ({ \
- int *__futex = &(NAME); \
- int __result = atomic_exchange_and_add_acq (__futex, 1); \
- /* If __result == 0, we succeeded in acquiring the lock. \
- If __result == 1, we switched the lock to 'contended' state, which \
- will cause a [possibly unnecessary] call to lll_futex_wait. This is \
- unlikely, so we accept the possible inefficiency. \
- If __result >= 2, we need to set the lock to 'contended' state to avoid \
- unbounded increase from subsequent trylocks. */ \
- if (__result >= 2) \
- __result = atomic_exchange_acq (__futex, 2); \
- __result; \
- })
-#endif
-
-#endif /* lowlevellock.h */
projects / platform / upstream / linaro-glibc.git / commitdiff