glibc/sysdeps/unix/sysv/linux/hppa/nptl/lowlevellock.h

/* Copyright (C) 2003, 2004, 2005 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, write to the Free
   Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
   02111-1307 USA.  */

#ifndef _LOWLEVELLOCK_H
#define _LOWLEVELLOCK_H	1

#include <time.h>
#include <sys/param.h>
#include <bits/pthreadtypes.h>
#include <sysdep.h>
#include <atomic.h>

#if 0
/* The hppa only has one atomic read and modify memory operation,
   load and clear, so hppa spinlocks must use zero to signify that
   someone is holding the lock.  The address used for the ldcw
   semaphore must be 16-byte aligned.  */
#define __ldcw(a) \
({ 									\
  unsigned int __ret;							\
  __asm__ __volatile__("ldcw 0(%1),%0"					\
                      : "=r" (__ret) : "r" (a) : "memory");		\
  __ret;								\
})

/* Because malloc only guarantees 8-byte alignment for malloc'd data,
   and GCC only guarantees 8-byte alignment for stack locals, we can't
   be assured of 16-byte alignment for atomic lock data even if we
   specify "__attribute ((aligned(16)))" in the type declaration.  So,
   we use a struct containing an array of four ints for the atomic lock
   type and dynamically select the 16-byte aligned int from the array
   for the semaphore.  */
#define __PA_LDCW_ALIGNMENT 16
#define __ldcw_align(a) ({ \
  volatile unsigned int __ret = (unsigned int) a;			\
  if ((__ret & ~(__PA_LDCW_ALIGNMENT - 1)) < (unsigned int) a)		\
    __ret = (__ret & ~(__PA_LDCW_ALIGNMENT - 1)) + __PA_LDCW_ALIGNMENT; \
  (unsigned int *) __ret;						\
})
#endif

#define FUTEX_WAIT		0
#define FUTEX_WAKE		1
#define FUTEX_REQUEUE		3
#define FUTEX_CMP_REQUEUE	4
#define FUTEX_WAKE_OP		5
#define FUTEX_OP_CLEAR_WAKE_IF_GT_ONE	((4 << 24) | 1)

/* Initializer for compatibility lock.	*/
#if 0
#define LLL_INITIALIZER_NOT_ZERO
#define LLL_MUTEX_LOCK_INITIALIZER ((__atomic_lock_t){ { 1, 1, 1, 1 } })
#endif
#define LLL_MUTEX_LOCK_INITIALIZER (0)


/* Type for lock object.  */
typedef int lll_lock_t;


#define lll_futex_wait(futexp, val) \
  ({									      \
    INTERNAL_SYSCALL_DECL (__err);					      \
    long int __ret;							      \
    __ret = INTERNAL_SYSCALL (futex, __err, 4,				      \
			      (futexp), FUTEX_WAIT, (val), 0);		      \
    INTERNAL_SYSCALL_ERROR_P (__ret, __err) ? -__ret : __ret;		      \
  })

#define lll_futex_timed_wait(futexp, val, timespec) \
  ({									      \
    INTERNAL_SYSCALL_DECL (__err);					      \
    long int __ret;							      \
    __ret = INTERNAL_SYSCALL (futex, __err, 4,				      \
			      (futexp), FUTEX_WAIT, (val), (timespec));	      \
    INTERNAL_SYSCALL_ERROR_P (__ret, __err) ? -__ret : __ret;		      \
  })

#define lll_futex_wake(futexp, nr) \
  ({									      \
    INTERNAL_SYSCALL_DECL (__err);					      \
    long int __ret;							      \
    __ret = INTERNAL_SYSCALL (futex, __err, 4,				      \
			      (futexp), FUTEX_WAKE, (nr), 0);		      \
    INTERNAL_SYSCALL_ERROR_P (__ret, __err) ? -__ret : __ret;		      \
  })

#define lll_robust_mutex_dead(futexv) \
  do									      \
    {									      \
      int *__futexp = &(futexv);					      \
      atomic_or (__futexp, FUTEX_OWNER_DIED);				      \
      lll_futex_wake (__futexp, 1);					      \
    }									      \
  while (0)

/* Returns non-zero if error happened, zero if success.  */
#define lll_futex_requeue(futexp, nr_wake, nr_move, mutex, val) \
  ({									      \
    INTERNAL_SYSCALL_DECL (__err);					      \
    long int __ret;							      \
    __ret = INTERNAL_SYSCALL (futex, __err, 6,				      \
			      (futexp), FUTEX_CMP_REQUEUE, (nr_wake),	      \
			      (nr_move), (mutex), (val));		      \
    INTERNAL_SYSCALL_ERROR_P (__ret, __err);				      \
  })

/* Returns non-zero if error happened, zero if success.  */
#define lll_futex_wake_unlock(futexp, nr_wake, nr_wake2, futexp2) \
  ({									      \
    INTERNAL_SYSCALL_DECL (__err);					      \
    long int __ret;							      \
    __ret = INTERNAL_SYSCALL (futex, __err, 6,				      \
			      (futexp), FUTEX_WAKE_OP, (nr_wake),	      \
			      (nr_wake2), (futexp2),			      \
			      FUTEX_OP_CLEAR_WAKE_IF_GT_ONE);		      \
    __ret;								      \
  })

static inline int __attribute__((always_inline))
__lll_mutex_trylock(lll_lock_t *futex)
{
  return atomic_compare_and_exchange_val_acq (futex, 1, 0) != 0;
}
#define lll_mutex_trylock(lock)	__lll_mutex_trylock (&(lock))

static inline int __attribute__((always_inline))
__lll_robust_mutex_trylock(int *futex, int id)
{
  return atomic_compare_and_exchange_val_acq (futex, id, 0) != 0;
}
#define lll_robust_mutex_trylock(lock, id) \
  __lll_robust_mutex_trylock (&(lock), id)


static inline int __attribute__((always_inline))
__lll_mutex_cond_trylock(lll_lock_t *futex)
{
  return atomic_compare_and_exchange_val_acq (futex, 2, 0) != 0;
}
#define lll_mutex_cond_trylock(lock)	__lll_mutex_cond_trylock (&(lock))


extern void __lll_lock_wait (lll_lock_t *futex) attribute_hidden;

static inline void __attribute__((always_inline))
__lll_mutex_lock(lll_lock_t *futex)
{
  if (atomic_compare_and_exchange_bool_acq (futex, 1, 0) != 0)
    __lll_lock_wait (futex);
}
#define lll_mutex_lock(futex) __lll_mutex_lock (&(futex))

extern int __lll_robust_lock_wait (int *futex) attribute_hidden;

static inline int __attribute__ ((always_inline))
__lll_robust_mutex_lock (int *futex, int id)
{
  int result = 0;
  if (atomic_compare_and_exchange_bool_acq (futex, id, 0) != 0)
    result = __lll_robust_lock_wait (futex);
  return result;
}
#define lll_robust_mutex_lock(futex, id) \
  __lll_robust_mutex_lock (&(futex), id)

static inline void __attribute__ ((always_inline))
__lll_mutex_cond_lock (lll_lock_t *futex)
{
  if (atomic_compare_and_exchange_bool_acq (futex, 2, 0) != 0)
    __lll_lock_wait (futex);
}
#define lll_mutex_cond_lock(futex) __lll_mutex_cond_lock (&(futex))


#define lll_robust_mutex_cond_lock(futex, id) \
  __lll_robust_mutex_lock (&(futex), (id) | FUTEX_WAITERS)


extern int __lll_timedlock_wait (lll_lock_t *futex, const struct timespec *)
	attribute_hidden;
extern int __lll_robust_timedlock_wait (int *futex, const struct timespec *)
	attribute_hidden;

static inline int __attribute__ ((always_inline))
__lll_mutex_timedlock (lll_lock_t *futex, const struct timespec *abstime)
{
  int result = 0;
  if (atomic_compare_and_exchange_bool_acq (futex, 1, 0) != 0)
    result = __lll_timedlock_wait (futex, abstime);
  return result;
}
#define lll_mutex_timedlock(futex, abstime) \
  __lll_mutex_timedlock (&(futex), abstime)

static inline int __attribute__ ((always_inline))
__lll_robust_mutex_timedlock (int *futex, const struct timespec *abstime,
			      int id)
{
  int result = 0;
  if (atomic_compare_and_exchange_bool_acq (futex, id, 0) != 0)
    result = __lll_robust_timedlock_wait (futex, abstime);
  return result;
}
#define lll_robust_mutex_timedlock(futex, abstime, id) \
  __lll_robust_mutex_timedlock (&(futex), abstime, id)


static inline void __attribute__ ((always_inline))
__lll_mutex_unlock (lll_lock_t *futex)
{
  int val = atomic_exchange_rel (futex, 0);
  if (__builtin_expect (val > 1, 0))
    lll_futex_wake (futex, 1);
}
#define lll_mutex_unlock(futex) __lll_mutex_unlock(&(futex))


static inline void __attribute__ ((always_inline))
__lll_robust_mutex_unlock (int *futex, int mask)
{
  int val = atomic_exchange_rel (futex, 0);
  if (__builtin_expect (val & mask, 0))
    lll_futex_wake (futex, 1);
}
#define lll_robust_mutex_unlock(futex) \
  __lll_robust_mutex_unlock(&(futex), FUTEX_WAITERS)


static inline void __attribute__ ((always_inline))
__lll_mutex_unlock_force (lll_lock_t *futex)
{
  (void) atomic_exchange_rel (futex, 0);
  lll_futex_wake (futex, 1);
}
#define lll_mutex_unlock_force(futex) __lll_mutex_unlock_force(&(futex))


static inline int __attribute__ ((always_inline))
__lll_mutex_islocked (lll_lock_t *futex)
{
  return (*futex != 0);
}
#define lll_mutex_islocked(futex) __lll_mutex_islocked(&(futex))


/* Our internal lock implementation is identical to the binary-compatible
   mutex implementation. */

/* Initializers for lock.  */
#if 0
#define LLL_LOCK_INITIALIZER		((__atomic_lock_t){ { 1, 1, 1, 1 } })
#define LLL_LOCK_INITIALIZER_CONST	{ { 1, 1, 1, 1 } }
#define LLL_LOCK_INITIALIZER_LOCKED	((__atomic_lock_t){ { 0, 0, 0, 0 } })
#endif

#define LLL_LOCK_INITIALIZER (0)
#define LLL_LOCK_INITIALIZER_CONST (0)
#define LLL_LOCK_INITIALIZER_LOCKED (1)


#define THREAD_INIT_LOCK(PD, LOCK) \
  (PD)->LOCK = LLL_LOCK_INITIALIZER

extern int lll_unlock_wake_cb (lll_lock_t *__futex) attribute_hidden;

/* The states of a lock are:
    0  -  untaken
    1  -  taken by one user
   >1  -  taken by more users */

#define lll_trylock(lock)	lll_mutex_trylock (lock)
#define lll_lock(lock)		lll_mutex_lock (lock)
#define lll_unlock(lock)	lll_mutex_unlock (lock)
#define lll_islocked(lock)	lll_mutex_islocked (lock)

/* The kernel notifies a process which uses CLONE_CLEARTID via futex
   wakeup when the clone terminates.  The memory location contains the
   thread ID while the clone is running and is reset to zero
   afterwards.	*/
#define lll_wait_tid(tid) \
  do {					\
    __typeof (tid) __tid;		\
    while ((__tid = (tid)) != 0)	\
      lll_futex_wait (&(tid), __tid);	\
  } while (0)

extern int __lll_timedwait_tid (int *, const struct timespec *)
     attribute_hidden;

#define lll_timedwait_tid(tid, abstime) \
  ({							\
    int __res = 0;					\
    if ((tid) != 0)					\
      __res = __lll_timedwait_tid (&(tid), (abstime));	\
    __res;						\
  })


/* Conditional variable handling.  */

extern void __lll_cond_wait (pthread_cond_t *cond)
     attribute_hidden;
extern int __lll_cond_timedwait (pthread_cond_t *cond,
				 const struct timespec *abstime)
     attribute_hidden;
extern void __lll_cond_wake (pthread_cond_t *cond)
     attribute_hidden;
extern void __lll_cond_broadcast (pthread_cond_t *cond)
     attribute_hidden;

#define lll_cond_wait(cond) \
  __lll_cond_wait (cond)
#define lll_cond_timedwait(cond, abstime) \
  __lll_cond_timedwait (cond, abstime)
#define lll_cond_wake(cond) \
  __lll_cond_wake (cond)
#define lll_cond_broadcast(cond) \
  __lll_cond_broadcast (cond)

#endif	/* lowlevellock.h */