VirtualBox

source: vbox/trunk/src/VBox/Runtime/generic/spinlock-generic.cpp@ 104509

Last change on this file since 104509 was 98103, checked in by vboxsync, 23 months ago

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1/* $Id: spinlock-generic.cpp 98103 2023-01-17 14:15:46Z vboxsync $ */
2/** @file
3 * IPRT - Spinlock, generic implementation.
4 */
5
6/*
7 * Copyright (C) 2006-2023 Oracle and/or its affiliates.
8 *
9 * This file is part of VirtualBox base platform packages, as
10 * available from https://www.virtualbox.org.
11 *
12 * This program is free software; you can redistribute it and/or
13 * modify it under the terms of the GNU General Public License
14 * as published by the Free Software Foundation, in version 3 of the
15 * License.
16 *
17 * This program is distributed in the hope that it will be useful, but
18 * WITHOUT ANY WARRANTY; without even the implied warranty of
19 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
20 * General Public License for more details.
21 *
22 * You should have received a copy of the GNU General Public License
23 * along with this program; if not, see <https://www.gnu.org/licenses>.
24 *
25 * The contents of this file may alternatively be used under the terms
26 * of the Common Development and Distribution License Version 1.0
27 * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
28 * in the VirtualBox distribution, in which case the provisions of the
29 * CDDL are applicable instead of those of the GPL.
30 *
31 * You may elect to license modified versions of this file under the
32 * terms and conditions of either the GPL or the CDDL or both.
33 *
34 * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
35 */
36
37
38/*********************************************************************************************************************************
39* Defined Constants And Macros *
40*********************************************************************************************************************************/
41/** @def RT_CFG_SPINLOCK_GENERIC_DO_SLEEP
42 * Force cpu yields after spinning the number of times indicated by the define.
43 * If 0 we will spin forever. */
44#define RT_CFG_SPINLOCK_GENERIC_DO_SLEEP 100000
45
46
47/*********************************************************************************************************************************
48* Header Files *
49*********************************************************************************************************************************/
50#include <iprt/spinlock.h>
51#include "internal/iprt.h"
52
53#include <iprt/alloc.h>
54#include <iprt/asm.h>
55#if defined(RT_ARCH_AMD64) || defined(RT_ARCH_X86)
56# include <iprt/asm-amd64-x86.h>
57#endif
58#include <iprt/errcore.h>
59#include <iprt/assert.h>
60#if RT_CFG_SPINLOCK_GENERIC_DO_SLEEP
61# include <iprt/thread.h>
62#endif
63
64#include "internal/magics.h"
65
66
67/*********************************************************************************************************************************
68* Structures and Typedefs *
69*********************************************************************************************************************************/
70/**
71 * Generic spinlock structure.
72 */
73typedef struct RTSPINLOCKINTERNAL
74{
75 /** Spinlock magic value (RTSPINLOCK_GEN_MAGIC). */
76 uint32_t u32Magic;
77 /** The spinlock creation flags. */
78 uint32_t fFlags;
79 /** The spinlock. */
80 uint32_t volatile fLocked;
81 /** The saved CPU interrupt. */
82 uint32_t volatile fIntSaved;
83} RTSPINLOCKINTERNAL, *PRTSPINLOCKINTERNAL;
84
85
86RTDECL(int) RTSpinlockCreate(PRTSPINLOCK pSpinlock, uint32_t fFlags, const char *pszName)
87{
88 PRTSPINLOCKINTERNAL pThis;
89 AssertReturn(fFlags == RTSPINLOCK_FLAGS_INTERRUPT_SAFE || fFlags == RTSPINLOCK_FLAGS_INTERRUPT_UNSAFE, VERR_INVALID_PARAMETER);
90 RT_NOREF_PV(pszName);
91
92 /*
93 * Allocate.
94 */
95 pThis = (PRTSPINLOCKINTERNAL)RTMemAlloc(sizeof(*pThis));
96 if (!pThis)
97 return VERR_NO_MEMORY;
98
99 /*
100 * Initialize and return.
101 */
102 pThis->u32Magic = RTSPINLOCK_GEN_MAGIC;
103 pThis->fFlags = fFlags;
104 pThis->fIntSaved = 0;
105 ASMAtomicWriteU32(&pThis->fLocked, 0);
106
107 *pSpinlock = pThis;
108 return VINF_SUCCESS;
109}
110RT_EXPORT_SYMBOL(RTSpinlockCreate);
111
112
113RTDECL(int) RTSpinlockDestroy(RTSPINLOCK Spinlock)
114{
115 /*
116 * Validate input.
117 */
118 PRTSPINLOCKINTERNAL pThis = (PRTSPINLOCKINTERNAL)Spinlock;
119 if (!pThis)
120 return VERR_INVALID_PARAMETER;
121 if (pThis->u32Magic != RTSPINLOCK_GEN_MAGIC)
122 {
123 AssertMsgFailed(("Invalid spinlock %p magic=%#x\n", pThis, pThis->u32Magic));
124 return VERR_INVALID_PARAMETER;
125 }
126
127 ASMAtomicIncU32(&pThis->u32Magic);
128 RTMemFree(pThis);
129 return VINF_SUCCESS;
130}
131RT_EXPORT_SYMBOL(RTSpinlockDestroy);
132
133
134RTDECL(void) RTSpinlockAcquire(RTSPINLOCK Spinlock)
135{
136 PRTSPINLOCKINTERNAL pThis = (PRTSPINLOCKINTERNAL)Spinlock;
137 AssertMsg(pThis && pThis->u32Magic == RTSPINLOCK_GEN_MAGIC,
138 ("pThis=%p u32Magic=%08x\n", pThis, pThis ? (int)pThis->u32Magic : 0));
139
140 if (pThis->fFlags & RTSPINLOCK_FLAGS_INTERRUPT_SAFE)
141 {
142#if defined(RT_ARCH_AMD64) || defined(RT_ARCH_X86)
143 uint32_t fIntSaved = ASMGetFlags();
144#endif
145
146#if RT_CFG_SPINLOCK_GENERIC_DO_SLEEP
147 for (;;)
148 {
149#if defined(RT_ARCH_AMD64) || defined(RT_ARCH_X86)
150 ASMIntDisable();
151#endif
152 for (int c = RT_CFG_SPINLOCK_GENERIC_DO_SLEEP; c > 0; c--)
153 {
154 if (ASMAtomicCmpXchgU32(&pThis->fLocked, 1, 0))
155 {
156# if defined(RT_ARCH_AMD64) || defined(RT_ARCH_X86)
157 pThis->fIntSaved = fIntSaved;
158# endif
159 return;
160 }
161 ASMNopPause();
162 }
163#if defined(RT_ARCH_AMD64) || defined(RT_ARCH_X86)
164 ASMSetFlags(fIntSaved);
165#endif
166 RTThreadYield();
167 }
168#else
169 for (;;)
170 {
171#if defined(RT_ARCH_AMD64) || defined(RT_ARCH_X86)
172 ASMIntDisable();
173#endif
174 if (ASMAtomicCmpXchgU32(&pThis->fLocked, 1, 0))
175 {
176# if defined(RT_ARCH_AMD64) || defined(RT_ARCH_X86)
177 pThis->fIntSaved = fIntSaved;
178# endif
179 return;
180 }
181#if defined(RT_ARCH_AMD64) || defined(RT_ARCH_X86)
182 ASMSetFlags(fIntSaved);
183#endif
184 ASMNopPause();
185 }
186#endif
187 }
188 else
189 {
190#if RT_CFG_SPINLOCK_GENERIC_DO_SLEEP
191 for (;;)
192 {
193 for (int c = RT_CFG_SPINLOCK_GENERIC_DO_SLEEP; c > 0; c--)
194 {
195 if (ASMAtomicCmpXchgU32(&pThis->fLocked, 1, 0))
196 return;
197 ASMNopPause();
198 }
199 RTThreadYield();
200 }
201#else
202 while (!ASMAtomicCmpXchgU32(&pThis->fLocked, 1, 0))
203 ASMNopPause();
204#endif
205 }
206}
207RT_EXPORT_SYMBOL(RTSpinlockAcquire);
208
209
210RTDECL(void) RTSpinlockRelease(RTSPINLOCK Spinlock)
211{
212 PRTSPINLOCKINTERNAL pThis = (PRTSPINLOCKINTERNAL)Spinlock;
213 AssertMsg(pThis && pThis->u32Magic == RTSPINLOCK_GEN_MAGIC,
214 ("pThis=%p u32Magic=%08x\n", pThis, pThis ? (int)pThis->u32Magic : 0));
215
216 if (pThis->fFlags & RTSPINLOCK_FLAGS_INTERRUPT_SAFE)
217 {
218#if defined(RT_ARCH_AMD64) || defined(RT_ARCH_X86)
219 uint32_t fIntSaved = pThis->fIntSaved;
220 pThis->fIntSaved = 0;
221#endif
222
223 if (!ASMAtomicCmpXchgU32(&pThis->fLocked, 0, 1))
224 AssertMsgFailed(("Spinlock %p was not locked!\n", pThis));
225
226#if defined(RT_ARCH_AMD64) || defined(RT_ARCH_X86)
227 ASMSetFlags(fIntSaved);
228#endif
229 }
230 else
231 {
232 if (!ASMAtomicCmpXchgU32(&pThis->fLocked, 0, 1))
233 AssertMsgFailed(("Spinlock %p was not locked!\n", pThis));
234 }
235}
236RT_EXPORT_SYMBOL(RTSpinlockRelease);
237
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