glibc/sysdeps/unix/sysv/linux/sparc/lowlevellock.h

/* Copyright (C) 2003-2019 Free Software Foundation, Inc.
   This file is part of the GNU C Library.
   Contributed by Jakub Jelinek <jakub@redhat.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/>.  */

#ifndef _LOWLEVELLOCK_H
#define _LOWLEVELLOCK_H	1

#include <time.h>
#include <sys/param.h>
#include <bits/pthreadtypes.h>
#include <atomic.h>
#include <kernel-features.h>
#include <errno.h>

#include <lowlevellock-futex.h>

static inline int
__attribute__ ((always_inline))
__lll_trylock (int *futex)
{
  return atomic_compare_and_exchange_val_24_acq (futex, 1, 0) != 0;
}
#define lll_trylock(futex) __lll_trylock (&(futex))

static inline int
__attribute__ ((always_inline))
__lll_cond_trylock (int *futex)
{
  return atomic_compare_and_exchange_val_24_acq (futex, 2, 0) != 0;
}
#define lll_cond_trylock(futex) __lll_cond_trylock (&(futex))


extern void __lll_lock_wait_private (int *futex) attribute_hidden;
extern void __lll_lock_wait (int *futex, int private) attribute_hidden;

static inline void
__attribute__ ((always_inline))
__lll_lock (int *futex, int private)
{
  int val = atomic_compare_and_exchange_val_24_acq (futex, 1, 0);

  if (__glibc_unlikely (val != 0))
    {
      if (__builtin_constant_p (private) && private == LLL_PRIVATE)
	__lll_lock_wait_private (futex);
      else
	__lll_lock_wait (futex, private);
    }
}
#define lll_lock(futex, private) __lll_lock (&(futex), private)

static inline void
__attribute__ ((always_inline))
__lll_cond_lock (int *futex, int private)
{
  int val = atomic_compare_and_exchange_val_24_acq (futex, 2, 0);

  if (__glibc_unlikely (val != 0))
    __lll_lock_wait (futex, private);
}
#define lll_cond_lock(futex, private) __lll_cond_lock (&(futex), private)


extern int __lll_clocklock_wait (int *futex, clockid_t, int val,
				 const struct timespec *,
				 int private) attribute_hidden;

#define lll_timedwait(futex, val, clockid, abstime, private)		\
  __lll_clocklock_wait (futex, val, clockid, abstime, private)

static inline int
__attribute__ ((always_inline))
__lll_clocklock (int *futex, clockid_t clockid,
                 const struct timespec *abstime, int private)
{
  int val = atomic_compare_and_exchange_val_24_acq (futex, 1, 0);
  int result = 0;

  if (__glibc_unlikely (val != 0))
    {
      do
	{
	  int oldval = atomic_compare_and_exchange_val_24_acq (futex, val, 1);
	  if (oldval != 0)
	    {
	      result = __lll_clocklock_wait (futex, 2, clockid, abstime,
					     private);
	      if (result == EINVAL || result == ETIMEDOUT)
		break;
	    }
        }
      while (atomic_compare_and_exchange_val_24_acq (futex, val, 0) != 0);
    }
  return result;
}
#define lll_clocklock(futex, clockid, abstime, private)  \
  __lll_clocklock (&(futex), clockid, abstime, private)

#define lll_unlock(lock, private) \
  ((void) ({								      \
    int *__futex = &(lock);						      \
    int __private = (private);						      \
    int __val = atomic_exchange_24_rel (__futex, 0);			      \
    if (__glibc_unlikely (__val > 1))					      \
      lll_futex_wake (__futex, 1, __private);				      \
  }))

#define lll_islocked(futex) \
  (futex != 0)

/* Initializers for lock.  */
#define LLL_LOCK_INITIALIZER		(0)
#define LLL_LOCK_INITIALIZER_LOCKED	(1)

#endif	/* lowlevellock.h */