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glibc/nptl/sem_init.c
Adhemerval Zanella 7fec8a5de6 Revert __HAVE_64B_ATOMICS configure check
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>
2025-11-14 14:05:20 -03:00

87 lines
2.4 KiB
C

/* Copyright (C) 2002-2025 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
<https://www.gnu.org/licenses/>. */
#include <errno.h>
#include <semaphore.h>
#include <shlib-compat.h>
#include "semaphoreP.h"
#include <kernel-features.h>
int
__new_sem_init (sem_t *sem, int pshared, unsigned int value)
{
ASSERT_PTHREAD_INTERNAL_SIZE (sem_t, struct new_sem);
/* Parameter sanity check. */
if (__glibc_unlikely (value > SEM_VALUE_MAX))
{
__set_errno (EINVAL);
return -1;
}
/* Map to the internal type. */
struct new_sem *isem = (struct new_sem *) sem;
/* Use the values the caller provided. */
#if USE_64B_ATOMICS
isem->data = value;
#else
isem->value = value << SEM_VALUE_SHIFT;
/* pad is used as a mutex on pre-v9 sparc and ignored otherwise. */
isem->pad = 0;
isem->nwaiters = 0;
#endif
isem->private = (pshared == 0 ? FUTEX_PRIVATE : FUTEX_SHARED);
return 0;
}
versioned_symbol (libc, __new_sem_init, sem_init, GLIBC_2_34);
#if OTHER_SHLIB_COMPAT(libpthread, GLIBC_2_1, GLIBC_2_34)
compat_symbol (libpthread, __new_sem_init, sem_init, GLIBC_2_1);
#endif
#if OTHER_SHLIB_COMPAT(libpthread, GLIBC_2_0, GLIBC_2_1)
int
attribute_compat_text_section
__old_sem_init (sem_t *sem, int pshared, unsigned int value)
{
ASSERT_PTHREAD_INTERNAL_SIZE (sem_t, struct new_sem);
/* Parameter sanity check. */
if (__glibc_unlikely (value > SEM_VALUE_MAX))
{
__set_errno (EINVAL);
return -1;
}
/* Map to the internal type. */
struct old_sem *isem = (struct old_sem *) sem;
/* Use the value the user provided. */
isem->value = value;
/* We cannot store the PSHARED attribute. So we always use the
operations needed for shared semaphores. */
return 0;
}
compat_symbol (libpthread, __old_sem_init, sem_init, GLIBC_2_0);
#endif