mirror of
https://sourceware.org/git/glibc.git
synced 2025-12-06 12:01:08 +03:00
7fec8a5de6
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>
57 lines
2.1 KiB
C
57 lines
2.1 KiB
C
/* RSEQ_* accessors. Generic version.
|
|
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 <atomic.h>
|
|
|
|
/* Read member of the RSEQ area directly. */
|
|
#define RSEQ_GETMEM(member) \
|
|
RSEQ_SELF()->member
|
|
|
|
/* Set member of the RSEQ area directly. */
|
|
#define RSEQ_SETMEM(member, value) \
|
|
RSEQ_SELF()->member = (value)
|
|
|
|
/* Static assert for types that can't be loaded/stored atomically on the
|
|
current architecture. */
|
|
#if USE_64B_ATOMICS
|
|
#define __RSEQ_ASSERT_ATOMIC(member) \
|
|
_Static_assert (sizeof (RSEQ_SELF()->member) == 1 \
|
|
|| sizeof (RSEQ_SELF()->member) == 4 \
|
|
|| sizeof (RSEQ_SELF()->member) == 8, \
|
|
"size of rseq data")
|
|
#else
|
|
#define __RSEQ_ASSERT_ATOMIC(member) \
|
|
_Static_assert (sizeof (RSEQ_SELF()->member) == 1 \
|
|
|| sizeof (RSEQ_SELF()->member) == 4, \
|
|
"size of rseq data")
|
|
#endif
|
|
|
|
/* Read member of the RSEQ area directly, with single-copy atomicity semantics. */
|
|
#define RSEQ_GETMEM_ONCE(member) \
|
|
({ \
|
|
__RSEQ_ASSERT_ATOMIC(member); \
|
|
(*(volatile __typeof (RSEQ_SELF()->member) *)&RSEQ_SELF()->member); \
|
|
})
|
|
|
|
/* Set member of the RSEQ area directly, with single-copy atomicity semantics. */
|
|
#define RSEQ_SETMEM_ONCE(member, value) \
|
|
({ \
|
|
__RSEQ_ASSERT_ATOMIC(member); \
|
|
(*(volatile __typeof (RSEQ_SELF()->member) *)&RSEQ_SELF()->member = (value)); \
|
|
})
|