Subversion Repositories HelenOS

/*

 * Copyright (c) 2001-2004 Jakub Jermar

 * All rights reserved.

 *

 * Redistribution and use in source and binary forms, with or without

 * modification, are permitted provided that the following conditions

 * are met:

 *

 * - Redistributions of source code must retain the above copyright

 *   notice, this list of conditions and the following disclaimer.

 * - Redistributions in binary form must reproduce the above copyright

 *   notice, this list of conditions and the following disclaimer in the

 *   documentation and/or other materials provided with the distribution.

 * - The name of the author may not be used to endorse or promote products

 *   derived from this software without specific prior written permission.

 *

 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR

 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES

 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.

 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,

 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT

 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,

 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY

 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT

 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF

 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

 */

/** @addtogroup sync

 * @{

 */

/** @file

 */

#ifndef KERN_SPINLOCK_H_

#define KERN_SPINLOCK_H_

#include <arch/types.h>

#include <arch/barrier.h>

#include <preemption.h>

#include <atomic.h>

#include <debug.h>

#ifdef CONFIG_SMP

typedef struct {

#ifdef CONFIG_DEBUG_SPINLOCK

    char *name;

#endif

    atomic_t val;

} spinlock_t;

/*

 * SPINLOCK_DECLARE is to be used for dynamically allocated spinlocks,

 * where the lock gets initialized in run time.

 */

#define SPINLOCK_DECLARE(slname)    spinlock_t slname

#define SPINLOCK_EXTERN(slname)     extern spinlock_t slname

/*

 * SPINLOCK_INITIALIZE is to be used for statically allocated spinlocks.

 * It declares and initializes the lock.

 */

#ifdef CONFIG_DEBUG_SPINLOCK

#define SPINLOCK_INITIALIZE(slname)     \

    spinlock_t slname = {       \

        .name = #slname,    \

        .val = { 0 }        \

    }

#else

#define SPINLOCK_INITIALIZE(slname)     \

    spinlock_t slname = {       \

        .val = { 0 }        \

    }

#endif

extern void spinlock_initialize(spinlock_t *sl, char *name);

extern int spinlock_trylock(spinlock_t *sl);

extern void spinlock_lock_debug(spinlock_t *sl);

#ifdef CONFIG_DEBUG_SPINLOCK

#  define spinlock_lock(x) spinlock_lock_debug(x)

#else

#  define spinlock_lock(x) atomic_lock_arch(&(x)->val)

#endif

/** Unlock spinlock

 *

 * Unlock spinlock.

 *

 * @param sl Pointer to spinlock_t structure.

 */

static inline void spinlock_unlock(spinlock_t *sl)

{

    ASSERT(atomic_get(&sl->val) != 0);

    /*

     * Prevent critical section code from bleeding out this way down.

     */

    CS_LEAVE_BARRIER();

    atomic_set(&sl->val, 0);

    preemption_enable();

}

#ifdef CONFIG_DEBUG_SPINLOCK

extern int printf(const char *, ...);

#define DEADLOCK_THRESHOLD      100000000

#define DEADLOCK_PROBE_INIT(pname)  size_t pname = 0

#define DEADLOCK_PROBE(pname, value)                    \

    if ((pname)++ > (value)) {                  \

        (pname) = 0;                        \

        printf("Deadlock probe %s: exceeded threshold %u\n",    \

            "cpu%u: function=%s, line=%u\n",            \

            #pname, (value), CPU->id, __func__, __LINE__);  \

    }

#else

#define DEADLOCK_PROBE_INIT(pname)

#define DEADLOCK_PROBE(pname, value)

#endif

#else

/* On UP systems, spinlocks are effectively left out. */

#define SPINLOCK_DECLARE(name)

#define SPINLOCK_EXTERN(name)

#define SPINLOCK_INITIALIZE(name)

#define spinlock_initialize(x, name)

#define spinlock_lock(x)        preemption_disable()

#define spinlock_trylock(x)         (preemption_disable(), 1)

#define spinlock_unlock(x)      preemption_enable()

#define DEADLOCK_PROBE_INIT(pname)

#define DEADLOCK_PROBE(pname, value)

#endif

#endif

/** @}

 */