VirtualBox

source: vbox/trunk/src/VBox/Runtime/r0drv/linux/semevent-r0drv-linux.c@ 62477

Last change on this file since 62477 was 62477, checked in by vboxsync, 8 years ago

(C) 2016
  • Property svn:eol-style set to native
  • Property svn:keywords set to Id Revision
File size: 8.8 KB
Line 
1/* $Id: semevent-r0drv-linux.c 62477 2016-07-22 18:27:37Z vboxsync $ */
2/** @file
3 * IPRT - Single Release Event Semaphores, Ring-0 Driver, Linux.
4 */
5
6/*
7 * Copyright (C) 2006-2016 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
77 AssertReturn(!(fFlags & ~(RTSEMEVENT_FLAGS_NO_LOCK_VAL | RTSEMEVENT_FLAGS_BOOTSTRAP_HACK)), VERR_INVALID_PARAMETER);
78 Assert(!(fFlags & RTSEMEVENT_FLAGS_BOOTSTRAP_HACK) || (fFlags & RTSEMEVENT_FLAGS_NO_LOCK_VAL));
79
80 pThis = (PRTSEMEVENTINTERNAL)RTMemAlloc(sizeof(*pThis));
81 if (!pThis)
82 return VERR_NO_MEMORY;
83
84 pThis->u32Magic = RTSEMEVENT_MAGIC;
85 pThis->fState = 0;
86 pThis->cRefs = 1;
87 init_waitqueue_head(&pThis->Head);
88
89 *phEventSem = pThis;
90 IPRT_LINUX_RESTORE_EFL_AC();
91 return VINF_SUCCESS;
92}
93RT_EXPORT_SYMBOL(RTSemEventCreate);
94
95
96/**
97 * Retains a reference to the event semaphore.
98 *
99 * @param pThis The event semaphore.
100 */
101DECLINLINE(void) rtR0SemEventLnxRetain(PRTSEMEVENTINTERNAL pThis)
102{
103 uint32_t cRefs = ASMAtomicIncU32(&pThis->cRefs);
104 Assert(cRefs < 100000); NOREF(cRefs);
105}
106
107
108/**
109 * Releases a reference to the event semaphore.
110 *
111 * @param pThis The event semaphore.
112 */
113DECLINLINE(void) rtR0SemEventLnxRelease(PRTSEMEVENTINTERNAL pThis)
114{
115 if (RT_UNLIKELY(ASMAtomicDecU32(&pThis->cRefs) == 0))
116 RTMemFree(pThis);
117}
118
119
120RTDECL(int) RTSemEventDestroy(RTSEMEVENT hEventSem)
121{
122 IPRT_LINUX_SAVE_EFL_AC();
123
124 /*
125 * Validate input.
126 */
127 PRTSEMEVENTINTERNAL pThis = hEventSem;
128 if (pThis == NIL_RTSEMEVENT)
129 return VINF_SUCCESS;
130 AssertMsgReturn(pThis->u32Magic == RTSEMEVENT_MAGIC, ("pThis->u32Magic=%RX32 pThis=%p\n", pThis->u32Magic, pThis), VERR_INVALID_HANDLE);
131 Assert(pThis->cRefs > 0);
132
133 /*
134 * Invalidate it and signal the object just in case.
135 */
136 ASMAtomicWriteU32(&pThis->u32Magic, ~RTSEMEVENT_MAGIC);
137 ASMAtomicWriteU32(&pThis->fState, 0);
138 Assert(!waitqueue_active(&pThis->Head));
139 wake_up_all(&pThis->Head);
140 rtR0SemEventLnxRelease(pThis);
141
142 IPRT_LINUX_RESTORE_EFL_AC();
143 return VINF_SUCCESS;
144}
145RT_EXPORT_SYMBOL(RTSemEventDestroy);
146
147
148RTDECL(int) RTSemEventSignal(RTSEMEVENT hEventSem)
149{
150 IPRT_LINUX_SAVE_EFL_AC();
151
152 /*
153 * Validate input.
154 */
155 PRTSEMEVENTINTERNAL pThis = (PRTSEMEVENTINTERNAL)hEventSem;
156 AssertPtrReturn(pThis, VERR_INVALID_HANDLE);
157 AssertMsgReturn(pThis->u32Magic == RTSEMEVENT_MAGIC, ("pThis->u32Magic=%RX32 pThis=%p\n", pThis->u32Magic, pThis), VERR_INVALID_HANDLE);
158 rtR0SemEventLnxRetain(pThis);
159
160 /*
161 * Signal the event object.
162 */
163 ASMAtomicWriteU32(&pThis->fState, 1);
164 wake_up(&pThis->Head);
165
166 rtR0SemEventLnxRelease(pThis);
167 IPRT_LINUX_RESTORE_EFL_AC();
168 return VINF_SUCCESS;
169}
170RT_EXPORT_SYMBOL(RTSemEventSignal);
171
172
173/**
174 * Worker for RTSemEventWaitEx and RTSemEventWaitExDebug.
175 *
176 * @returns VBox status code.
177 * @param pThis The event semaphore.
178 * @param fFlags See RTSemEventWaitEx.
179 * @param uTimeout See RTSemEventWaitEx.
180 * @param pSrcPos The source code position of the wait.
181 */
182static int rtR0SemEventLnxWait(PRTSEMEVENTINTERNAL pThis, uint32_t fFlags, uint64_t uTimeout,
183 PCRTLOCKVALSRCPOS pSrcPos)
184{
185 int rc;
186
187 /*
188 * Validate the input.
189 */
190 AssertPtrReturn(pThis, VERR_INVALID_PARAMETER);
191 AssertMsgReturn(pThis->u32Magic == RTSEMEVENT_MAGIC, ("%p u32Magic=%RX32\n", pThis, pThis->u32Magic), VERR_INVALID_PARAMETER);
192 AssertReturn(RTSEMWAIT_FLAGS_ARE_VALID(fFlags), VERR_INVALID_PARAMETER);
193 rtR0SemEventLnxRetain(pThis);
194
195 /*
196 * Try grab the event without setting up the wait.
197 */
198 if ( 1 /** @todo check if there are someone waiting already - waitqueue_active, but then what do we do below? */
199 && ASMAtomicCmpXchgU32(&pThis->fState, 0, 1))
200 rc = VINF_SUCCESS;
201 else
202 {
203 /*
204 * We have to wait.
205 */
206 IPRT_LINUX_SAVE_EFL_AC();
207 RTR0SEMLNXWAIT Wait;
208 rc = rtR0SemLnxWaitInit(&Wait, fFlags, uTimeout, &pThis->Head);
209 if (RT_SUCCESS(rc))
210 {
211 IPRT_DEBUG_SEMS_STATE(pThis, 'E');
212 for (;;)
213 {
214 /* The destruction test. */
215 if (RT_UNLIKELY(pThis->u32Magic != RTSEMEVENT_MAGIC))
216 rc = VERR_SEM_DESTROYED;
217 else
218 {
219 rtR0SemLnxWaitPrepare(&Wait);
220
221 /* Check the exit conditions. */
222 if (RT_UNLIKELY(pThis->u32Magic != RTSEMEVENT_MAGIC))
223 rc = VERR_SEM_DESTROYED;
224 else if (ASMAtomicCmpXchgU32(&pThis->fState, 0, 1))
225 rc = VINF_SUCCESS;
226 else if (rtR0SemLnxWaitHasTimedOut(&Wait))
227 rc = VERR_TIMEOUT;
228 else if (rtR0SemLnxWaitWasInterrupted(&Wait))
229 rc = VERR_INTERRUPTED;
230 else
231 {
232 /* Do the wait and then recheck the conditions. */
233 rtR0SemLnxWaitDoIt(&Wait);
234 continue;
235 }
236 }
237 break;
238 }
239
240 rtR0SemLnxWaitDelete(&Wait);
241 IPRT_DEBUG_SEMS_STATE_RC(pThis, 'E', rc);
242 }
243 IPRT_LINUX_RESTORE_EFL_AC();
244 }
245
246 rtR0SemEventLnxRelease(pThis);
247 return rc;
248}
249
250
251RTDECL(int) RTSemEventWaitEx(RTSEMEVENT hEventSem, uint32_t fFlags, uint64_t uTimeout)
252{
253#ifndef RTSEMEVENT_STRICT
254 return rtR0SemEventLnxWait(hEventSem, fFlags, uTimeout, NULL);
255#else
256 RTLOCKVALSRCPOS SrcPos = RTLOCKVALSRCPOS_INIT_NORMAL_API();
257 return rtR0SemEventLnxWait(hEventSem, fFlags, uTimeout, &SrcPos);
258#endif
259}
260RT_EXPORT_SYMBOL(RTSemEventWaitEx);
261
262
263RTDECL(int) RTSemEventWaitExDebug(RTSEMEVENT hEventSem, uint32_t fFlags, uint64_t uTimeout,
264 RTHCUINTPTR uId, RT_SRC_POS_DECL)
265{
266 RTLOCKVALSRCPOS SrcPos = RTLOCKVALSRCPOS_INIT_DEBUG_API();
267 return rtR0SemEventLnxWait(hEventSem, fFlags, uTimeout, &SrcPos);
268}
269RT_EXPORT_SYMBOL(RTSemEventWaitExDebug);
270
271
272RTDECL(uint32_t) RTSemEventGetResolution(void)
273{
274 return rtR0SemLnxWaitGetResolution();
275}
276RT_EXPORT_SYMBOL(RTSemEventGetResolution);
277
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