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The 53807741fb added a configure check
for 64-bit atomic operations that were not previously enabled on some
32-bit ABIs.
However, the NPTL semaphore code casts a sem_t to a new_sem and issues
a 64-bit atomic operation for __HAVE_64B_ATOMICS. Since sem_t has
32-bit alignment on 32-bit architectures, this prevents the use of
64-bit atomics even if the ABI supports them.
Assume 64-bit atomic support from __WORDSIZE, which maps to how glibc
defines it before the broken change. Also rename __HAVE_64B_ATOMICS
to USE_64B_ATOMICS to define better the flag meaning.
Checked on x86_64-linux-gnu and i686-linux-gnu.
Reviewed-by: Wilco Dijkstra <Wilco.Dijkstra@arm.com>
87 lines
2.4 KiB
C
87 lines
2.4 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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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 <errno.h>
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#include <semaphore.h>
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#include <shlib-compat.h>
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#include "semaphoreP.h"
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#include <kernel-features.h>
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int
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__new_sem_init (sem_t *sem, int pshared, unsigned int value)
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{
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ASSERT_PTHREAD_INTERNAL_SIZE (sem_t, struct new_sem);
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/* Parameter sanity check. */
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if (__glibc_unlikely (value > SEM_VALUE_MAX))
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{
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__set_errno (EINVAL);
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return -1;
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}
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/* Map to the internal type. */
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struct new_sem *isem = (struct new_sem *) sem;
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/* Use the values the caller provided. */
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#if USE_64B_ATOMICS
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isem->data = value;
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#else
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isem->value = value << SEM_VALUE_SHIFT;
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/* pad is used as a mutex on pre-v9 sparc and ignored otherwise. */
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isem->pad = 0;
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isem->nwaiters = 0;
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#endif
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isem->private = (pshared == 0 ? FUTEX_PRIVATE : FUTEX_SHARED);
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return 0;
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}
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versioned_symbol (libc, __new_sem_init, sem_init, GLIBC_2_34);
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#if OTHER_SHLIB_COMPAT(libpthread, GLIBC_2_1, GLIBC_2_34)
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compat_symbol (libpthread, __new_sem_init, sem_init, GLIBC_2_1);
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#endif
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#if OTHER_SHLIB_COMPAT(libpthread, GLIBC_2_0, GLIBC_2_1)
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int
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attribute_compat_text_section
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__old_sem_init (sem_t *sem, int pshared, unsigned int value)
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{
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ASSERT_PTHREAD_INTERNAL_SIZE (sem_t, struct new_sem);
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/* Parameter sanity check. */
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if (__glibc_unlikely (value > SEM_VALUE_MAX))
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{
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__set_errno (EINVAL);
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return -1;
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}
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/* Map to the internal type. */
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struct old_sem *isem = (struct old_sem *) sem;
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/* Use the value the user provided. */
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isem->value = value;
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/* We cannot store the PSHARED attribute. So we always use the
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operations needed for shared semaphores. */
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return 0;
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}
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compat_symbol (libpthread, __old_sem_init, sem_init, GLIBC_2_0);
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#endif
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