glibc/nptl/lowlevellock.c
Florian Weimer 7c241325d6 Force building with -fno-common
As a result, is not necessary to specify __attribute__ ((nocommon))
on individual definitions.

GCC 10 defaults to -fno-common on all architectures except ARC,
but this change is compatible with older GCC versions and ARC, too.

Reviewed-by: Carlos O'Donell <carlos@redhat.com>
2021-07-09 20:09:14 +02:00

73 lines
2.0 KiB
C

/* low level locking for pthread library. Generic futex-using version.
Copyright (C) 2003-2021 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Contributed by Paul Mackerras <paulus@au.ibm.com>, 2003.
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 <sysdep.h>
#include <futex-internal.h>
#include <atomic.h>
#include <stap-probe.h>
void
__lll_lock_wait_private (int *futex)
{
if (atomic_load_relaxed (futex) == 2)
goto futex;
while (atomic_exchange_acquire (futex, 2) != 0)
{
futex:
LIBC_PROBE (lll_lock_wait_private, 1, futex);
futex_wait ((unsigned int *) futex, 2, LLL_PRIVATE); /* Wait if *futex == 2. */
}
}
libc_hidden_def (__lll_lock_wait_private)
void
__lll_lock_wait (int *futex, int private)
{
if (atomic_load_relaxed (futex) == 2)
goto futex;
while (atomic_exchange_acquire (futex, 2) != 0)
{
futex:
LIBC_PROBE (lll_lock_wait, 1, futex);
futex_wait ((unsigned int *) futex, 2, private); /* Wait if *futex == 2. */
}
}
libc_hidden_def (__lll_lock_wait)
void
__lll_lock_wake_private (int *futex)
{
lll_futex_wake (futex, 1, LLL_PRIVATE);
}
libc_hidden_def (__lll_lock_wake_private)
void
__lll_lock_wake (int *futex, int private)
{
lll_futex_wake (futex, 1, private);
}
libc_hidden_def (__lll_lock_wake)
#if ENABLE_ELISION_SUPPORT
int __pthread_force_elision;
libc_hidden_data_def (__pthread_force_elision)
#endif