/usr/include/atomic_ops/sysdeps/loadstore/acquire_release_volatile.h is in libatomic-ops-dev 7.4.2-1.
This file is owned by root:root, with mode 0o644.
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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 | /*
* Copyright (c) 2003-2004 Hewlett-Packard Development Company, L.P.
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
* SOFTWARE.
*/
/* This file adds definitions appropriate for environments in which */
/* volatile load of a given type has acquire semantics, and volatile */
/* store of a given type has release semantics. This is arguably */
/* supposed to be true with the standard Itanium software conventions. */
/* Empirically gcc/ia64 does some reordering of ordinary operations */
/* around volatiles even when we think it should not. GCC v3.3 and */
/* earlier could reorder a volatile store with another store. As of */
/* March 2005, gcc pre-4 reuses some previously computed common */
/* subexpressions across a volatile load; hence, we now add compiler */
/* barriers for gcc. */
#ifndef AO_GCC_BARRIER
/* TODO: Check GCC version (if workaround not needed for modern GCC). */
# if defined(__GNUC__)
# define AO_GCC_BARRIER() AO_compiler_barrier()
# else
# define AO_GCC_BARRIER() (void)0
# endif
#endif
AO_INLINE AO_t
AO_load_acquire(const volatile AO_t *addr)
{
AO_t result = *addr;
/* A normal volatile load generates an ld.acq (on IA-64). */
AO_GCC_BARRIER();
return result;
}
#define AO_HAVE_load_acquire
AO_INLINE void
AO_store_release(volatile AO_t *addr, AO_t new_val)
{
AO_GCC_BARRIER();
/* A normal volatile store generates an st.rel (on IA-64). */
*addr = new_val;
}
#define AO_HAVE_store_release
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