/* $Id: semevent-r0drv-solaris.c 30933 2010-07-20 16:16:06Z vboxsync $ */ /** @file * IPRT - Semaphores, Ring-0 Driver, Solaris. */ /* * Copyright (C) 2006-2010 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-solaris-kernel.h" #include "internal/iprt.h" #include #include #include #if defined(RT_ARCH_AMD64) || defined(RT_ARCH_X86) # include #endif #include #include #include #include #include "internal/magics.h" /******************************************************************************* * Structures and Typedefs * *******************************************************************************/ /** * Solaris event semaphore. */ typedef struct RTSEMEVENTINTERNAL { /** Magic value (RTSEMEVENT_MAGIC). */ uint32_t volatile u32Magic; /** The number of threads referencing this object. */ uint32_t volatile cRefs; /** Set if the object is signalled when there are no waiters. */ bool fSignaled; /** Object generation. * This is incremented every time the object is signalled and used to * check for spurious wake-ups. */ uint32_t uSignalGen; /** The number of waiting threads. */ uint32_t cWaiters; /** The number of signalled threads. */ uint32_t cWakeUp; /** The Solaris mutex protecting this structure and pairing up the with the cv. */ kmutex_t Mtx; /** The Solaris condition variable. */ kcondvar_t Cnd; } RTSEMEVENTINTERNAL, *PRTSEMEVENTINTERNAL; RTDECL(int) RTSemEventCreate(PRTSEMEVENT phEventSem) { return RTSemEventCreateEx(phEventSem, 0 /*fFlags*/, NIL_RTLOCKVALCLASS, NULL); } RTDECL(int) RTSemEventCreateEx(PRTSEMEVENT phEventSem, uint32_t fFlags, RTLOCKVALCLASS hClass, const char *pszNameFmt, ...) { AssertCompile(sizeof(RTSEMEVENTINTERNAL) > sizeof(void *)); AssertReturn(!(fFlags & ~RTSEMEVENT_FLAGS_NO_LOCK_VAL), VERR_INVALID_PARAMETER); AssertPtrReturn(phEventSem, VERR_INVALID_POINTER); RT_ASSERT_PREEMPTIBLE(); PRTSEMEVENTINTERNAL pThis = (PRTSEMEVENTINTERNAL)RTMemAlloc(sizeof(*pThis)); if (!pThis) return VERR_NO_MEMORY; pThis->u32Magic = RTSEMEVENT_MAGIC; pThis->cRefs = 1; pThis->fSignaled = false; pThis->uSignalGen = 0; pThis->cWaiters = 0; pThis->cWakeUp = 0; mutex_init(&pThis->Mtx, "IPRT Event Semaphore", MUTEX_DRIVER, (void *)ipltospl(DISP_LEVEL)); cv_init(&pThis->Cnd, "IPRT CV", CV_DRIVER, NULL); *phEventSem = pThis; return VINF_SUCCESS; } RTDECL(int) RTSemEventDestroy(RTSEMEVENT hEventSem) { PRTSEMEVENTINTERNAL pThis = hEventSem; if (pThis == NIL_RTSEMEVENT) return VINF_SUCCESS; AssertPtrReturn(pThis, VERR_INVALID_HANDLE); AssertMsgReturn(pThis->u32Magic == RTSEMEVENT_MAGIC, ("u32Magic=%RX32 pThis=%p\n", pThis->u32Magic, pThis), VERR_INVALID_HANDLE); RT_ASSERT_INTS_ON(); mutex_enter(&pThis->Mtx); ASMAtomicDecU32(&pThis->cRefs); pThis->u32Magic = RTSEMEVENT_MAGIC_DEAD; /* make the handle invalid */ if (pThis->cWaiters > 0) { /* * Signal all threads to destroy. */ cv_broadcast(&pThis->Cnd); mutex_exit(&pThis->Mtx); } else if (pThis->cRefs == 0) { /* * We're the last thread referencing this object, destroy it. */ mutex_exit(&pThis->Mtx); cv_destroy(&pThis->Cnd); mutex_destroy(&pThis->Mtx); RTMemFree(pThis); } else { /* * There are other threads still referencing this object, last one cleans up. */ mutex_exit(&pThis->Mtx); } return VINF_SUCCESS; } RTDECL(int) RTSemEventSignal(RTSEMEVENT hEventSem) { PRTSEMEVENTINTERNAL pThis = (PRTSEMEVENTINTERNAL)hEventSem; RT_ASSERT_PREEMPT_CPUID_VAR(); AssertPtrReturn(pThis, VERR_INVALID_HANDLE); AssertMsgReturn(pThis->u32Magic == RTSEMEVENT_MAGIC, ("u32Magic=%RX32 pThis=%p\n", pThis->u32Magic, pThis), VERR_INVALID_HANDLE); RT_ASSERT_INTS_ON(); /* * If we're in interrupt context we need to unpin the underlying current * thread as this could lead to a deadlock (see #4259 for the full explanation) * * Note! This assumes nobody is using the RTThreadPreemptDisable in an * interrupt context and expects it to work right. The swtch will * result in a voluntary preemption. To fix this, we would have to * do our own counting in RTThreadPreemptDisable/Restore like we do * on systems which doesn't do preemption (OS/2, linux, ...) and * check whether preemption was disabled via RTThreadPreemptDisable * or not and only call swtch if RTThreadPreemptDisable wasn't called. */ int fAcquired = mutex_tryenter(&pThis->Mtx); if (!fAcquired) { if (curthread->t_intr && getpil() < DISP_LEVEL) { RTTHREADPREEMPTSTATE PreemptState = RTTHREADPREEMPTSTATE_INITIALIZER; RTThreadPreemptDisable(&PreemptState); preempt(); RTThreadPreemptRestore(&PreemptState); } mutex_enter(&pThis->Mtx); } /* * If there are more waiting threads, wake them up. Otherwise leave the * semaphore in the signalled state. */ pThis->cWakeUp++; if (pThis->cWakeUp <= pThis->cWaiters) /** @todo r=bird: see cWakeup = 0 below. */ { cv_signal(&pThis->Cnd); pThis->uSignalGen++; } else pThis->fSignaled = true; mutex_exit(&pThis->Mtx); RT_ASSERT_PREEMPT_CPUID(); return VINF_SUCCESS; } static int rtSemEventWaitWorker(PRTSEMEVENTINTERNAL pThis, RTMSINTERVAL cMillies, bool fInterruptible) { /* * Translate milliseconds into ticks and go to sleep. */ int rc = 0; if (cMillies != RT_INDEFINITE_WAIT) { clock_t cTicks = drv_usectohz((clock_t)(cMillies * 1000L)); clock_t cTimeout = ddi_get_lbolt(); cTimeout += cTicks; if (fInterruptible) rc = cv_timedwait_sig(&pThis->Cnd, &pThis->Mtx, cTimeout); else rc = cv_timedwait(&pThis->Cnd, &pThis->Mtx, cTimeout); } else { if (fInterruptible) rc = cv_wait_sig(&pThis->Cnd, &pThis->Mtx); else { cv_wait(&pThis->Cnd, &pThis->Mtx); rc = 1; } } return rc; } static int rtSemEventWait(RTSEMEVENT hEventSem, RTMSINTERVAL cMillies, bool fInterruptible) { int rc; PRTSEMEVENTINTERNAL pThis = (PRTSEMEVENTINTERNAL)hEventSem; AssertPtrReturn(pThis, VERR_INVALID_HANDLE); AssertMsgReturn(pThis->u32Magic == RTSEMEVENT_MAGIC, ("u32Magic=%RX32 pThis=%p\n", pThis->u32Magic, pThis), VERR_INVALID_HANDLE); if (cMillies) RT_ASSERT_PREEMPTIBLE(); mutex_enter(&pThis->Mtx); ASMAtomicIncU32(&pThis->cRefs); if (pThis->fSignaled) { /* * The last signal occurred without any waiters and now we're the first thread * waiting for the event signal. So no real need to wait for one. */ Assert(!pThis->cWaiters); pThis->fSignaled = false; /** @todo r=bird: This will get out of whack if someone is in the * process of waking up (waiting to be scheduled). Further * more, a race between a cv_signal and a * timeout/interruption may cause wakeups to go unconsumed. * Not sure how we could easily deal with this rigth now... */ pThis->cWakeUp = 0; rc = VINF_SUCCESS; } else if (!cMillies) rc = VERR_TIMEOUT; else { pThis->cWaiters++; /* This loop is only for continuing after a spurious wake-up. */ for (;;) { uint32_t const uSignalGenBeforeWait = pThis->uSignalGen; rc = rtSemEventWaitWorker(pThis, cMillies, fInterruptible); if (rc > 0) { if (pThis->u32Magic == RTSEMEVENT_MAGIC) { if (pThis->uSignalGen != uSignalGenBeforeWait) { /* We've been signaled by cv_signal(), consume the wake up. */ --pThis->cWakeUp; /** @todo r=bird: May cause underflow, see above. */ rc = VINF_SUCCESS; } else /* Spurious wakeup due to some signal, go back to waiting. */ continue; } else /* We're being destroyed. */ rc = VERR_SEM_DESTROYED; } else if (rc == -1) /* Timeout reached. */ rc = VERR_TIMEOUT; else /* Returned due to pending signal */ rc = VERR_INTERRUPTED; break; } --pThis->cWaiters; } if (!ASMAtomicDecU32(&pThis->cRefs)) { Assert(RT_FAILURE_NP(rc)); mutex_exit(&pThis->Mtx); cv_destroy(&pThis->Cnd); mutex_destroy(&pThis->Mtx); RTMemFree(pThis); return rc; } mutex_exit(&pThis->Mtx); return rc; } RTDECL(int) RTSemEventWait(RTSEMEVENT hEventSem, RTMSINTERVAL cMillies) { return rtSemEventWait(hEventSem, cMillies, false /* not interruptible */); } RTDECL(int) RTSemEventWaitNoResume(RTSEMEVENT hEventSem, RTMSINTERVAL cMillies) { return rtSemEventWait(hEventSem, cMillies, true /* interruptible */); }