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3dd2cbfa35
commit 7fec8a5de6
Author: Adhemerval Zanella <adhemerval.zanella@linaro.org>
Date: Thu Nov 13 14:26:08 2025 -0300
Revert __HAVE_64B_ATOMICS configure check
uses 64-bit atomic operations on sem_t if 64-bit atomics are supported.
But sem_t may be aligned to 32-bit on 32-bit architectures.
1. Add a macro, SEM_T_ALIGN, for sem_t alignment.
2. Add a macro, HAVE_UNALIGNED_64B_ATOMICS. Define it if unaligned 64-bit
atomic operations are supported.
3. Add a macro, USE_64B_ATOMICS_ON_SEM_T. Define to 1 if 64-bit atomic
operations are supported and SEM_T_ALIGN is at least 8-byte aligned or
HAVE_UNALIGNED_64B_ATOMICS is defined.
4. Assert that size and alignment of sem_t are not lower than those of
the internal struct new_sem.
5. Check USE_64B_ATOMICS_ON_SEM_T, instead of USE_64B_ATOMICS, when using
64-bit atomic operations on sem_t.
This fixes BZ #33632.
Reviewed-by: Wilco Dijkstra <Wilco.Dijkstra@arm.com>
62 lines
2.1 KiB
C
62 lines
2.1 KiB
C
/* Copyright (C) 2002-2025 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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Ulrich Drepper <drepper@redhat.com>, 2002.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, see
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<https://www.gnu.org/licenses/>. */
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#include <semaphore.h>
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#include <futex-internal.h>
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#include "pthreadP.h"
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#define SEM_SHM_PREFIX "sem."
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static inline void __new_sem_open_init (struct new_sem *sem, unsigned value)
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{
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#if USE_64B_ATOMICS_ON_SEM_T
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sem->data = value;
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#else
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sem->value = value << SEM_VALUE_SHIFT;
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sem->nwaiters = 0;
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#endif
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/* pad is used as a mutex on pre-v9 sparc and ignored otherwise. */
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sem->pad = 0;
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/* This always is a shared semaphore. */
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sem->private = FUTEX_SHARED;
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}
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/* Prototypes of functions with multiple interfaces. */
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extern int __new_sem_init (sem_t *sem, int pshared, unsigned int value);
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extern int __old_sem_init (sem_t *sem, int pshared, unsigned int value);
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extern int __new_sem_destroy (sem_t *sem);
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extern int __new_sem_post (sem_t *sem);
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extern int __new_sem_wait (sem_t *sem);
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extern int __old_sem_wait (sem_t *sem);
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extern int __new_sem_trywait (sem_t *sem);
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extern int __new_sem_getvalue (sem_t *sem, int *sval);
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#if __TIMESIZE == 64
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# define __sem_clockwait64 __sem_clockwait
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# define __sem_timedwait64 __sem_timedwait
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#else
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extern int
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__sem_clockwait64 (sem_t *sem, clockid_t clockid,
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const struct __timespec64 *abstime);
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libc_hidden_proto (__sem_clockwait64)
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extern int
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__sem_timedwait64 (sem_t *sem, const struct __timespec64 *abstime);
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libc_hidden_proto (__sem_timedwait64)
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#endif
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