VirtualBox

source: vbox/trunk/src/VBox/Runtime/r0drv/linux/semevent-r0drv-linux.c@ 82968

Last change on this file since 82968 was 82968, checked in by vboxsync, 5 years ago

Copyright year updates by scm.
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1/* $Id: semevent-r0drv-linux.c 82968 2020-02-04 10:35:17Z vboxsync $ */
2/** @file
3 * IPRT - Single Release Event Semaphores, Ring-0 Driver, Linux.
4 */
5
6/*
7 * Copyright (C) 2006-2020 Oracle Corporation
8 *
9 * This file is part of VirtualBox Open Source Edition (OSE), as
10 * available from http://www.virtualbox.org. This file is free software;
11 * you can redistribute it and/or modify it under the terms of the GNU
12 * General Public License (GPL) as published by the Free Software
13 * Foundation, in version 2 as it comes in the "COPYING" file of the
14 * VirtualBox OSE distribution. VirtualBox OSE is distributed in the
15 * hope that it will be useful, but WITHOUT ANY WARRANTY of any kind.
16 *
17 * The contents of this file may alternatively be used under the terms
18 * of the Common Development and Distribution License Version 1.0
19 * (CDDL) only, as it comes in the "COPYING.CDDL" file of the
20 * VirtualBox OSE distribution, in which case the provisions of the
21 * CDDL are applicable instead of those of the GPL.
22 *
23 * You may elect to license modified versions of this file under the
24 * terms and conditions of either the GPL or the CDDL or both.
25 */
26
27
28/*********************************************************************************************************************************
29* Header Files *
30*********************************************************************************************************************************/
31#define RTSEMEVENT_WITHOUT_REMAPPING
32#include "the-linux-kernel.h"
33#include "internal/iprt.h"
34#include <iprt/semaphore.h>
35
36#include <iprt/asm.h>
37#include <iprt/assert.h>
38#include <iprt/err.h>
39#include <iprt/lockvalidator.h>
40#include <iprt/mem.h>
41
42#include "waitqueue-r0drv-linux.h"
43#include "internal/magics.h"
44
45
46/*********************************************************************************************************************************
47* Structures and Typedefs *
48*********************************************************************************************************************************/
49/**
50 * Linux event semaphore.
51 */
52typedef struct RTSEMEVENTINTERNAL
53{
54 /** Magic value (RTSEMEVENT_MAGIC). */
55 uint32_t volatile u32Magic;
56 /** The object status - !0 when signaled and 0 when reset. */
57 uint32_t volatile fState;
58 /** Reference counter. */
59 uint32_t volatile cRefs;
60 /** The wait queue. */
61 wait_queue_head_t Head;
62} RTSEMEVENTINTERNAL, *PRTSEMEVENTINTERNAL;
63
64
65
66RTDECL(int) RTSemEventCreate(PRTSEMEVENT phEventSem)
67{
68 return RTSemEventCreateEx(phEventSem, 0 /*fFlags*/, NIL_RTLOCKVALCLASS, NULL);
69}
70
71
72RTDECL(int) RTSemEventCreateEx(PRTSEMEVENT phEventSem, uint32_t fFlags, RTLOCKVALCLASS hClass, const char *pszNameFmt, ...)
73{
74 PRTSEMEVENTINTERNAL pThis;
75 IPRT_LINUX_SAVE_EFL_AC();
76 RT_NOREF_PV(hClass); RT_NOREF_PV(pszNameFmt);
77
78 AssertReturn(!(fFlags & ~(RTSEMEVENT_FLAGS_NO_LOCK_VAL | RTSEMEVENT_FLAGS_BOOTSTRAP_HACK)), VERR_INVALID_PARAMETER);
79 Assert(!(fFlags & RTSEMEVENT_FLAGS_BOOTSTRAP_HACK) || (fFlags & RTSEMEVENT_FLAGS_NO_LOCK_VAL));
80
81 pThis = (PRTSEMEVENTINTERNAL)RTMemAlloc(sizeof(*pThis));
82 if (!pThis)
83 return VERR_NO_MEMORY;
84
85 pThis->u32Magic = RTSEMEVENT_MAGIC;
86 pThis->fState = 0;
87 pThis->cRefs = 1;
88 init_waitqueue_head(&pThis->Head);
89
90 *phEventSem = pThis;
91 IPRT_LINUX_RESTORE_EFL_AC();
92 return VINF_SUCCESS;
93}
94RT_EXPORT_SYMBOL(RTSemEventCreate);
95
96
97/**
98 * Retains a reference to the event semaphore.
99 *
100 * @param pThis The event semaphore.
101 */
102DECLINLINE(void) rtR0SemEventLnxRetain(PRTSEMEVENTINTERNAL pThis)
103{
104 uint32_t cRefs = ASMAtomicIncU32(&pThis->cRefs);
105 Assert(cRefs < 100000); NOREF(cRefs);
106}
107
108
109/**
110 * Releases a reference to the event semaphore.
111 *
112 * @param pThis The event semaphore.
113 */
114DECLINLINE(void) rtR0SemEventLnxRelease(PRTSEMEVENTINTERNAL pThis)
115{
116 if (RT_UNLIKELY(ASMAtomicDecU32(&pThis->cRefs) == 0))
117 RTMemFree(pThis);
118}
119
120
121RTDECL(int) RTSemEventDestroy(RTSEMEVENT hEventSem)
122{
123 IPRT_LINUX_SAVE_EFL_AC();
124
125 /*
126 * Validate input.
127 */
128 PRTSEMEVENTINTERNAL pThis = hEventSem;
129 if (pThis == NIL_RTSEMEVENT)
130 return VINF_SUCCESS;
131 AssertMsgReturn(pThis->u32Magic == RTSEMEVENT_MAGIC, ("pThis->u32Magic=%RX32 pThis=%p\n", pThis->u32Magic, pThis), VERR_INVALID_HANDLE);
132 Assert(pThis->cRefs > 0);
133
134 /*
135 * Invalidate it and signal the object just in case.
136 */
137 ASMAtomicWriteU32(&pThis->u32Magic, ~RTSEMEVENT_MAGIC);
138 ASMAtomicWriteU32(&pThis->fState, 0);
139 Assert(!waitqueue_active(&pThis->Head));
140 wake_up_all(&pThis->Head);
141 rtR0SemEventLnxRelease(pThis);
142
143 IPRT_LINUX_RESTORE_EFL_AC();
144 return VINF_SUCCESS;
145}
146RT_EXPORT_SYMBOL(RTSemEventDestroy);
147
148
149RTDECL(int) RTSemEventSignal(RTSEMEVENT hEventSem)
150{
151 IPRT_LINUX_SAVE_EFL_AC();
152
153 /*
154 * Validate input.
155 */
156 PRTSEMEVENTINTERNAL pThis = (PRTSEMEVENTINTERNAL)hEventSem;
157 AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
158 AssertMsgReturn(pThis->u32Magic == RTSEMEVENT_MAGIC, ("pThis->u32Magic=%RX32 pThis=%p\n", pThis->u32Magic, pThis), VERR_INVALID_HANDLE);
159 rtR0SemEventLnxRetain(pThis);
160
161 /*
162 * Signal the event object.
163 */
164 ASMAtomicWriteU32(&pThis->fState, 1);
165 wake_up(&pThis->Head);
166
167 rtR0SemEventLnxRelease(pThis);
168 IPRT_LINUX_RESTORE_EFL_AC();
169 return VINF_SUCCESS;
170}
171RT_EXPORT_SYMBOL(RTSemEventSignal);
172
173
174/**
175 * Worker for RTSemEventWaitEx and RTSemEventWaitExDebug.
176 *
177 * @returns VBox status code.
178 * @param pThis The event semaphore.
179 * @param fFlags See RTSemEventWaitEx.
180 * @param uTimeout See RTSemEventWaitEx.
181 * @param pSrcPos The source code position of the wait.
182 */
183static int rtR0SemEventLnxWait(PRTSEMEVENTINTERNAL pThis, uint32_t fFlags, uint64_t uTimeout,
184 PCRTLOCKVALSRCPOS pSrcPos)
185{
186 int rc;
187 RT_NOREF_PV(pSrcPos);
188
189 /*
190 * Validate the input.
191 */
192 AssertPtrReturn(pThis, VERR_INVALID_PARAMETER);
193 AssertMsgReturn(pThis->u32Magic == RTSEMEVENT_MAGIC, ("%p u32Magic=%RX32\n", pThis, pThis->u32Magic), VERR_INVALID_PARAMETER);
194 AssertReturn(RTSEMWAIT_FLAGS_ARE_VALID(fFlags), VERR_INVALID_PARAMETER);
195 rtR0SemEventLnxRetain(pThis);
196
197 /*
198 * Try grab the event without setting up the wait.
199 */
200 if ( 1 /** @todo check if there are someone waiting already - waitqueue_active, but then what do we do below? */
201 && ASMAtomicCmpXchgU32(&pThis->fState, 0, 1))
202 rc = VINF_SUCCESS;
203 else
204 {
205 /*
206 * We have to wait.
207 */
208 IPRT_LINUX_SAVE_EFL_AC();
209 RTR0SEMLNXWAIT Wait;
210 rc = rtR0SemLnxWaitInit(&Wait, fFlags, uTimeout, &pThis->Head);
211 if (RT_SUCCESS(rc))
212 {
213 IPRT_DEBUG_SEMS_STATE(pThis, 'E');
214 for (;;)
215 {
216 /* The destruction test. */
217 if (RT_UNLIKELY(pThis->u32Magic != RTSEMEVENT_MAGIC))
218 rc = VERR_SEM_DESTROYED;
219 else
220 {
221 rtR0SemLnxWaitPrepare(&Wait);
222
223 /* Check the exit conditions. */
224 if (RT_UNLIKELY(pThis->u32Magic != RTSEMEVENT_MAGIC))
225 rc = VERR_SEM_DESTROYED;
226 else if (ASMAtomicCmpXchgU32(&pThis->fState, 0, 1))
227 rc = VINF_SUCCESS;
228 else if (rtR0SemLnxWaitHasTimedOut(&Wait))
229 rc = VERR_TIMEOUT;
230 else if (rtR0SemLnxWaitWasInterrupted(&Wait))
231 rc = VERR_INTERRUPTED;
232 else
233 {
234 /* Do the wait and then recheck the conditions. */
235 rtR0SemLnxWaitDoIt(&Wait);
236 continue;
237 }
238 }
239 break;
240 }
241
242 rtR0SemLnxWaitDelete(&Wait);
243 IPRT_DEBUG_SEMS_STATE_RC(pThis, 'E', rc);
244 }
245 IPRT_LINUX_RESTORE_EFL_AC();
246 }
247
248 rtR0SemEventLnxRelease(pThis);
249 return rc;
250}
251
252
253RTDECL(int) RTSemEventWaitEx(RTSEMEVENT hEventSem, uint32_t fFlags, uint64_t uTimeout)
254{
255#ifndef RTSEMEVENT_STRICT
256 return rtR0SemEventLnxWait(hEventSem, fFlags, uTimeout, NULL);
257#else
258 RTLOCKVALSRCPOS SrcPos = RTLOCKVALSRCPOS_INIT_NORMAL_API();
259 return rtR0SemEventLnxWait(hEventSem, fFlags, uTimeout, &SrcPos);
260#endif
261}
262RT_EXPORT_SYMBOL(RTSemEventWaitEx);
263
264
265RTDECL(int) RTSemEventWaitExDebug(RTSEMEVENT hEventSem, uint32_t fFlags, uint64_t uTimeout,
266 RTHCUINTPTR uId, RT_SRC_POS_DECL)
267{
268 RTLOCKVALSRCPOS SrcPos = RTLOCKVALSRCPOS_INIT_DEBUG_API();
269 return rtR0SemEventLnxWait(hEventSem, fFlags, uTimeout, &SrcPos);
270}
271RT_EXPORT_SYMBOL(RTSemEventWaitExDebug);
272
273
274RTDECL(uint32_t) RTSemEventGetResolution(void)
275{
276 return rtR0SemLnxWaitGetResolution();
277}
278RT_EXPORT_SYMBOL(RTSemEventGetResolution);
279
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