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/* $Id: thread-r0drv-linux.c $ */
/** @file
* IPRT - Threads, Ring-0 Driver, Linux.
*/
/*
* Copyright (C) 2006-2019 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/thread.h>
#include <iprt/asm.h>
#if LINUX_VERSION_CODE < KERNEL_VERSION(2, 5, 28) || defined(CONFIG_X86_SMAP)
# include <iprt/asm-amd64-x86.h>
#endif
#include <iprt/assert.h>
#include <iprt/errcore.h>
#include <iprt/mp.h>
/*********************************************************************************************************************************
* Global Variables *
*********************************************************************************************************************************/
#ifndef CONFIG_PREEMPT
/** Per-cpu preemption counters. */
static int32_t volatile g_acPreemptDisabled[NR_CPUS];
#endif
RTDECL(RTNATIVETHREAD) RTThreadNativeSelf(void)
{
return (RTNATIVETHREAD)current;
}
RT_EXPORT_SYMBOL(RTThreadNativeSelf);
static int rtR0ThreadLnxSleepCommon(RTMSINTERVAL cMillies)
{
IPRT_LINUX_SAVE_EFL_AC();
long cJiffies = msecs_to_jiffies(cMillies);
set_current_state(TASK_INTERRUPTIBLE);
cJiffies = schedule_timeout(cJiffies);
IPRT_LINUX_RESTORE_EFL_AC();
if (!cJiffies)
return VINF_SUCCESS;
return VERR_INTERRUPTED;
}
RTDECL(int) RTThreadSleep(RTMSINTERVAL cMillies)
{
return rtR0ThreadLnxSleepCommon(cMillies);
}
RT_EXPORT_SYMBOL(RTThreadSleep);
RTDECL(int) RTThreadSleepNoLog(RTMSINTERVAL cMillies)
{
return rtR0ThreadLnxSleepCommon(cMillies);
}
RT_EXPORT_SYMBOL(RTThreadSleepNoLog);
RTDECL(bool) RTThreadYield(void)
{
IPRT_LINUX_SAVE_EFL_AC();
#if LINUX_VERSION_CODE >= KERNEL_VERSION(2, 4, 20)
yield();
#else
/** @todo r=ramshankar: Can we use cond_resched() instead? */
set_current_state(TASK_RUNNING);
sys_sched_yield();
schedule();
#endif
IPRT_LINUX_RESTORE_EFL_AC();
return true;
}
RT_EXPORT_SYMBOL(RTThreadYield);
RTDECL(bool) RTThreadPreemptIsEnabled(RTTHREAD hThread)
{
#ifdef CONFIG_PREEMPT
Assert(hThread == NIL_RTTHREAD); RT_NOREF_PV(hThread);
# ifdef preemptible
return preemptible();
# else
return preempt_count() == 0 && !in_atomic() && !irqs_disabled();
# endif
#else
int32_t c;
Assert(hThread == NIL_RTTHREAD);
c = g_acPreemptDisabled[smp_processor_id()];
AssertMsg(c >= 0 && c < 32, ("%d\n", c));
if (c != 0)
return false;
# if LINUX_VERSION_CODE >= KERNEL_VERSION(2, 5, 32)
if (in_atomic())
return false;
# endif
# if LINUX_VERSION_CODE >= KERNEL_VERSION(2, 5, 28)
if (irqs_disabled())
return false;
# else
if (!ASMIntAreEnabled())
return false;
# endif
return true;
#endif
}
RT_EXPORT_SYMBOL(RTThreadPreemptIsEnabled);
RTDECL(bool) RTThreadPreemptIsPending(RTTHREAD hThread)
{
Assert(hThread == NIL_RTTHREAD); RT_NOREF_PV(hThread);
#if LINUX_VERSION_CODE >= KERNEL_VERSION(2, 5, 4)
return !!test_tsk_thread_flag(current, TIF_NEED_RESCHED);
#elif LINUX_VERSION_CODE >= KERNEL_VERSION(2, 4, 20)
return !!need_resched();
#elif LINUX_VERSION_CODE >= KERNEL_VERSION(2, 1, 110)
return current->need_resched != 0;
#else
return need_resched != 0;
#endif
}
RT_EXPORT_SYMBOL(RTThreadPreemptIsPending);
RTDECL(bool) RTThreadPreemptIsPendingTrusty(void)
{
/* yes, RTThreadPreemptIsPending is reliable. */
return true;
}
RT_EXPORT_SYMBOL(RTThreadPreemptIsPendingTrusty);
RTDECL(bool) RTThreadPreemptIsPossible(void)
{
#ifdef CONFIG_PREEMPT
return true; /* Yes, kernel preemption is possible. */
#else
return false; /* No kernel preemption (or CONFIG_PREEMPT_VOLUNTARY). */
#endif
}
RT_EXPORT_SYMBOL(RTThreadPreemptIsPossible);
RTDECL(void) RTThreadPreemptDisable(PRTTHREADPREEMPTSTATE pState)
{
#ifdef CONFIG_PREEMPT
AssertPtr(pState);
Assert(pState->u32Reserved == 0);
pState->u32Reserved = 42;
/* This ASSUMES that CONFIG_PREEMPT_COUNT is always defined with CONFIG_PREEMPT. */
preempt_disable();
RT_ASSERT_PREEMPT_CPUID_DISABLE(pState);
#else /* !CONFIG_PREEMPT */
int32_t c;
AssertPtr(pState);
Assert(pState->u32Reserved == 0);
/* Do our own accounting. */
c = ASMAtomicIncS32(&g_acPreemptDisabled[smp_processor_id()]);
AssertMsg(c > 0 && c < 32, ("%d\n", c));
pState->u32Reserved = c;
RT_ASSERT_PREEMPT_CPUID_DISABLE(pState);
#endif
}
RT_EXPORT_SYMBOL(RTThreadPreemptDisable);
RTDECL(void) RTThreadPreemptRestore(PRTTHREADPREEMPTSTATE pState)
{
#ifdef CONFIG_PREEMPT
IPRT_LINUX_SAVE_EFL_AC(); /* paranoia */
AssertPtr(pState);
Assert(pState->u32Reserved == 42);
RT_ASSERT_PREEMPT_CPUID_RESTORE(pState);
preempt_enable();
IPRT_LINUX_RESTORE_EFL_ONLY_AC(); /* paranoia */
#else
int32_t volatile *pc;
AssertPtr(pState);
AssertMsg(pState->u32Reserved > 0 && pState->u32Reserved < 32, ("%d\n", pState->u32Reserved));
RT_ASSERT_PREEMPT_CPUID_RESTORE(pState);
/* Do our own accounting. */
pc = &g_acPreemptDisabled[smp_processor_id()];
AssertMsg(pState->u32Reserved == (uint32_t)*pc, ("u32Reserved=%d *pc=%d \n", pState->u32Reserved, *pc));
ASMAtomicUoWriteS32(pc, pState->u32Reserved - 1);
#endif
pState->u32Reserved = 0;
}
RT_EXPORT_SYMBOL(RTThreadPreemptRestore);
RTDECL(bool) RTThreadIsInInterrupt(RTTHREAD hThread)
{
Assert(hThread == NIL_RTTHREAD); NOREF(hThread);
return in_interrupt() != 0;
}
RT_EXPORT_SYMBOL(RTThreadIsInInterrupt);
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