/* $Id: spinlock-r0drv-darwin.cpp 52618 2014-09-05 12:07:29Z vboxsync $ */
/** @file
 * IPRT - Spinlocks, Ring-0 Driver, Darwin.
 */

/*
 * Copyright (C) 2006-2014 Oracle Corporation
 *
 * This file is part of VirtualBox Open Source Edition (OSE), as
 * available from http://www.virtualbox.org. This file is free software;
 * you can redistribute it and/or modify it under the terms of the GNU
 * General Public License (GPL) as published by the Free Software
 * Foundation, in version 2 as it comes in the "COPYING" file of the
 * VirtualBox OSE distribution. VirtualBox OSE is distributed in the
 * hope that it will be useful, but WITHOUT ANY WARRANTY of any kind.
 *
 * The contents of this file may alternatively be used under the terms
 * of the Common Development and Distribution License Version 1.0
 * (CDDL) only, as it comes in the "COPYING.CDDL" file of the
 * VirtualBox OSE distribution, in which case the provisions of the
 * CDDL are applicable instead of those of the GPL.
 *
 * You may elect to license modified versions of this file under the
 * terms and conditions of either the GPL or the CDDL or both.
 */


/*******************************************************************************
*   Header Files                                                               *
*******************************************************************************/
#include "the-darwin-kernel.h"
#include "internal/iprt.h"
#include <iprt/spinlock.h>

#include <iprt/assert.h>
#include <iprt/asm.h>
#if defined(RT_ARCH_AMD64) || defined(RT_ARCH_X86)
# include <iprt/asm-amd64-x86.h>
#endif
#include <iprt/err.h>
#include <iprt/mem.h>
#include <iprt/thread.h>

#include "internal/magics.h"


/*******************************************************************************
*   Structures and Typedefs                                                    *
*******************************************************************************/
/**
 * Wrapper for the KSPIN_LOCK type.
 */
typedef struct RTSPINLOCKINTERNAL
{
    /** Spinlock magic value (RTSPINLOCK_MAGIC). */
    uint32_t volatile   u32Magic;
    /** Saved interrupt flag. */
    uint32_t volatile   fIntSaved;
    /** Creation flags. */
    uint32_t            fFlags;
    /** The Darwin spinlock structure. */
    lck_spin_t         *pSpinLock;
    /** The spinlock name. */
    const char         *pszName;
} RTSPINLOCKINTERNAL, *PRTSPINLOCKINTERNAL;



RTDECL(int)  RTSpinlockCreate(PRTSPINLOCK pSpinlock, uint32_t fFlags, const char *pszName)
{
    RT_ASSERT_PREEMPTIBLE();
    AssertReturn(fFlags == RTSPINLOCK_FLAGS_INTERRUPT_SAFE || fFlags == RTSPINLOCK_FLAGS_INTERRUPT_UNSAFE, VERR_INVALID_PARAMETER);

    /*
     * Allocate.
     */
    AssertCompile(sizeof(RTSPINLOCKINTERNAL) > sizeof(void *));
    PRTSPINLOCKINTERNAL pThis = (PRTSPINLOCKINTERNAL)RTMemAlloc(sizeof(*pThis));
    if (!pThis)
        return VERR_NO_MEMORY;

    /*
     * Initialize & return.
     */
    pThis->u32Magic  = RTSPINLOCK_MAGIC;
    pThis->fIntSaved = 0;
    pThis->fFlags    = fFlags;
    pThis->pszName   = pszName;
    Assert(g_pDarwinLockGroup);
    pThis->pSpinLock = lck_spin_alloc_init(g_pDarwinLockGroup, LCK_ATTR_NULL);
    if (!pThis->pSpinLock)
    {
        RTMemFree(pThis);
        return VERR_NO_MEMORY;
    }

    *pSpinlock = pThis;
    return VINF_SUCCESS;
}


RTDECL(int)  RTSpinlockDestroy(RTSPINLOCK Spinlock)
{
    /*
     * Validate input.
     */
    PRTSPINLOCKINTERNAL pThis = (PRTSPINLOCKINTERNAL)Spinlock;
    if (!pThis)
        return VERR_INVALID_PARAMETER;
    AssertMsgReturn(pThis->u32Magic == RTSPINLOCK_MAGIC,
                    ("Invalid spinlock %p magic=%#x\n", pThis, pThis->u32Magic),
                    VERR_INVALID_PARAMETER);

    /*
     * Make the lock invalid and release the memory.
     */
    ASMAtomicIncU32(&pThis->u32Magic);

    Assert(g_pDarwinLockGroup);
    lck_spin_destroy(pThis->pSpinLock, g_pDarwinLockGroup);
    pThis->pSpinLock = NULL;

    RTMemFree(pThis);
    return VINF_SUCCESS;
}


RTDECL(void) RTSpinlockAcquire(RTSPINLOCK Spinlock)
{
    PRTSPINLOCKINTERNAL pThis = (PRTSPINLOCKINTERNAL)Spinlock;
    AssertPtr(pThis);
    Assert(pThis->u32Magic == RTSPINLOCK_MAGIC);

    if (pThis->fFlags & RTSPINLOCK_FLAGS_INTERRUPT_SAFE)
    {
        uint32_t fIntSaved = ASMGetFlags();
        ASMIntDisable();
        lck_spin_lock(pThis->pSpinLock);
        pThis->fIntSaved = fIntSaved;
    }
    else
        lck_spin_lock(pThis->pSpinLock);
}


RTDECL(void) RTSpinlockRelease(RTSPINLOCK Spinlock)
{
    PRTSPINLOCKINTERNAL pThis = (PRTSPINLOCKINTERNAL)Spinlock;
    AssertPtr(pThis);
    Assert(pThis->u32Magic == RTSPINLOCK_MAGIC);

    if (pThis->fFlags & RTSPINLOCK_FLAGS_INTERRUPT_SAFE)
    {
        uint32_t fIntSaved = pThis->fIntSaved;
        pThis->fIntSaved = 0;
        lck_spin_unlock(pThis->pSpinLock);
        ASMSetFlags(fIntSaved);
    }
    else
        lck_spin_unlock(pThis->pSpinLock);
}