/* $Id: thread2-r0drv-linux.c 109135 2016-07-26 15:16:41Z bird $ */
/** @file
 * IPRT - Threads (Part 2), Ring-0 Driver, Linux.
 */

/*
 * Copyright (C) 2006-2016 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-linux-kernel.h"
#include "internal/iprt.h"

#include <iprt/assert.h>
#include <iprt/thread.h>
#include <iprt/err.h>
#include "internal/thread.h"

RTDECL(RTTHREAD) RTThreadSelf(void)
{
	return rtThreadGetByNative((RTNATIVETHREAD) current);
}

DECLHIDDEN(int)rtThreadNativeInit(void)
{
	return VINF_SUCCESS;
}

DECLHIDDEN(int)rtThreadNativeSetPriority(PRTTHREADINT pThread,
					 RTTHREADTYPE enmType)
{
#if LINUX_VERSION_CODE >= KERNEL_VERSION(2, 6, 11)
	/* See comment near MAX_RT_PRIO in linux/sched.h for details on
	   sched_priority. */
	int iSchedClass = SCHED_NORMAL;
	struct sched_param Param = {.sched_priority = MAX_PRIO - 1 };
	switch (enmType) {
	case RTTHREADTYPE_INFREQUENT_POLLER:
		Param.sched_priority = MAX_RT_PRIO + 5;
		break;

	case RTTHREADTYPE_EMULATION:
		Param.sched_priority = MAX_RT_PRIO + 4;
		break;

	case RTTHREADTYPE_DEFAULT:
		Param.sched_priority = MAX_RT_PRIO + 3;
		break;

	case RTTHREADTYPE_MSG_PUMP:
		Param.sched_priority = MAX_RT_PRIO + 2;
		break;

	case RTTHREADTYPE_IO:
		iSchedClass = SCHED_FIFO;
		Param.sched_priority = MAX_RT_PRIO - 1;
		break;

	case RTTHREADTYPE_TIMER:
		iSchedClass = SCHED_FIFO;
		Param.sched_priority = 1;	/* not 0 just in case */
		break;

	default:
		AssertMsgFailed(("enmType=%d\n", enmType));
		return VERR_INVALID_PARAMETER;
	}

	sched_setscheduler(current, iSchedClass, &Param);
#else
	RT_NOREF_PV(enmType);
#endif
	RT_NOREF_PV(pThread);

	return VINF_SUCCESS;
}

DECLHIDDEN(int)rtThreadNativeAdopt(PRTTHREADINT pThread)
{
	RT_NOREF_PV(pThread);
	return VERR_NOT_IMPLEMENTED;
}

DECLHIDDEN(void)rtThreadNativeWaitKludge(PRTTHREADINT pThread)
{
    /** @todo fix RTThreadWait/RTR0Term race on linux. */
	RTThreadSleep(1);
	NOREF(pThread);
}

DECLHIDDEN(void) rtThreadNativeDestroy(PRTTHREADINT pThread)
{
	NOREF(pThread);
}

#if LINUX_VERSION_CODE >= KERNEL_VERSION(2, 6, 4)
/**
 * Native kernel thread wrapper function.
 *
 * This will forward to rtThreadMain and do termination upon return.
 *
 * @param pvArg         Pointer to the argument package.
 */
static int rtThreadNativeMain(void *pvArg)
{
	PRTTHREADINT pThread = (PRTTHREADINT) pvArg;

	rtThreadMain(pThread, (RTNATIVETHREAD) current, &pThread->szName[0]);
	return 0;
}
#endif

DECLHIDDEN(int)rtThreadNativeCreate(PRTTHREADINT pThreadInt,
				    PRTNATIVETHREAD pNativeThread)
{
#if LINUX_VERSION_CODE >= KERNEL_VERSION(2, 6, 4)
	struct task_struct *NativeThread;
	IPRT_LINUX_SAVE_EFL_AC();

	RT_ASSERT_PREEMPTIBLE();

	NativeThread =
	    kthread_run(rtThreadNativeMain, pThreadInt, "iprt-%s",
			pThreadInt->szName);

	if (!IS_ERR(NativeThread)) {
		*pNativeThread = (RTNATIVETHREAD) NativeThread;
		IPRT_LINUX_RESTORE_EFL_AC();
		return VINF_SUCCESS;
	}
	IPRT_LINUX_RESTORE_EFL_AC();
	return VERR_GENERAL_FAILURE;
#else
	return VERR_NOT_IMPLEMENTED;
#endif
}
