| 1 | /* $Id: spinlock-r0drv-linux.c 98103 2023-01-17 14:15:46Z vboxsync $ */
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| 2 | /** @file
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| 3 | * IPRT - Spinlocks, Ring-0 Driver, Linux.
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| 4 | */
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| 5 |
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| 6 | /*
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| 7 | * Copyright (C) 2006-2023 Oracle and/or its affiliates.
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| 8 | *
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| 9 | * This file is part of VirtualBox base platform packages, as
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| 10 | * available from https://www.virtualbox.org.
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| 11 | *
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| 12 | * This program is free software; you can redistribute it and/or
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| 13 | * modify it under the terms of the GNU General Public License
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| 14 | * as published by the Free Software Foundation, in version 3 of the
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| 15 | * License.
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| 16 | *
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| 17 | * This program is distributed in the hope that it will be useful, but
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| 18 | * WITHOUT ANY WARRANTY; without even the implied warranty of
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| 19 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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| 20 | * General Public License for more details.
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| 21 | *
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| 22 | * You should have received a copy of the GNU General Public License
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| 23 | * along with this program; if not, see <https://www.gnu.org/licenses>.
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| 24 | *
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| 25 | * The contents of this file may alternatively be used under the terms
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| 26 | * of the Common Development and Distribution License Version 1.0
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| 27 | * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
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| 28 | * in the VirtualBox distribution, in which case the provisions of the
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| 29 | * CDDL are applicable instead of those of the GPL.
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| 30 | *
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| 31 | * You may elect to license modified versions of this file under the
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| 32 | * terms and conditions of either the GPL or the CDDL or both.
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| 33 | *
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| 34 | * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
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| 35 | */
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| 36 |
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| 37 |
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| 38 | /*********************************************************************************************************************************
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| 39 | * Header Files *
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| 40 | *********************************************************************************************************************************/
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| 41 | #include "the-linux-kernel.h"
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| 42 | #include "internal/iprt.h"
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| 43 | #include <iprt/spinlock.h>
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| 44 |
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| 45 | #include <iprt/asm.h>
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| 46 | #if defined(RT_ARCH_AMD64) || defined(RT_ARCH_X86)
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| 47 | # include <iprt/asm-amd64-x86.h>
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| 48 | #endif
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| 49 | #include <iprt/assert.h>
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| 50 | #include <iprt/errcore.h>
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| 51 | #include <iprt/mem.h>
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| 52 | #include <iprt/mp.h>
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| 53 | #include <iprt/thread.h>
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| 54 | #include "internal/magics.h"
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| 55 |
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| 56 |
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| 57 | /*********************************************************************************************************************************
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| 58 | * Structures and Typedefs *
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| 59 | *********************************************************************************************************************************/
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| 60 | /**
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| 61 | * Wrapper for the spinlock_t structure.
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| 62 | */
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| 63 | typedef struct RTSPINLOCKINTERNAL
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| 64 | {
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| 65 | /** Spinlock magic value (RTSPINLOCK_MAGIC). */
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| 66 | uint32_t volatile u32Magic;
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| 67 | /** The spinlock creation flags. */
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| 68 | uint32_t fFlags;
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| 69 | /** The saved interrupt flag. */
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| 70 | unsigned long volatile fIntSaved;
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| 71 | /** The linux spinlock structure. */
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| 72 | spinlock_t Spinlock;
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| 73 | #ifdef RT_MORE_STRICT
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| 74 | /** The idAssertCpu variable before acquring the lock for asserting after
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| 75 | * releasing the spinlock. */
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| 76 | RTCPUID volatile idAssertCpu;
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| 77 | /** The CPU that owns the lock. */
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| 78 | RTCPUID volatile idCpuOwner;
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| 79 | #endif
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| 80 | } RTSPINLOCKINTERNAL, *PRTSPINLOCKINTERNAL;
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| 81 |
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| 82 |
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| 83 |
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| 84 | RTDECL(int) RTSpinlockCreate(PRTSPINLOCK pSpinlock, uint32_t fFlags, const char *pszName)
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| 85 | {
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| 86 | IPRT_LINUX_SAVE_EFL_AC();
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| 87 | PRTSPINLOCKINTERNAL pThis;
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| 88 | AssertReturn(fFlags == RTSPINLOCK_FLAGS_INTERRUPT_SAFE || fFlags == RTSPINLOCK_FLAGS_INTERRUPT_UNSAFE, VERR_INVALID_PARAMETER);
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| 89 | RT_NOREF_PV(pszName);
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| 90 |
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| 91 | /*
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| 92 | * Allocate.
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| 93 | */
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| 94 | Assert(sizeof(RTSPINLOCKINTERNAL) > sizeof(void *));
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| 95 | pThis = (PRTSPINLOCKINTERNAL)RTMemAlloc(sizeof(*pThis));
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| 96 | if (!pThis)
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| 97 | return VERR_NO_MEMORY;
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| 98 | /*
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| 99 | * Initialize and return.
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| 100 | */
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| 101 | pThis->u32Magic = RTSPINLOCK_MAGIC;
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| 102 | pThis->fFlags = fFlags;
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| 103 | pThis->fIntSaved = 0;
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| 104 | #ifdef RT_MORE_STRICT
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| 105 | pThis->idCpuOwner = NIL_RTCPUID;
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| 106 | pThis->idAssertCpu = NIL_RTCPUID;
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| 107 | #endif
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| 108 |
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| 109 | spin_lock_init(&pThis->Spinlock);
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| 110 |
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| 111 | *pSpinlock = pThis;
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| 112 | IPRT_LINUX_RESTORE_EFL_AC();
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| 113 | return VINF_SUCCESS;
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| 114 | }
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| 115 | RT_EXPORT_SYMBOL(RTSpinlockCreate);
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| 116 |
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| 117 |
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| 118 | RTDECL(int) RTSpinlockDestroy(RTSPINLOCK Spinlock)
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| 119 | {
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| 120 | /*
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| 121 | * Validate input.
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| 122 | */
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| 123 | PRTSPINLOCKINTERNAL pThis = (PRTSPINLOCKINTERNAL)Spinlock;
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| 124 | if (!pThis)
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| 125 | return VERR_INVALID_PARAMETER;
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| 126 | if (pThis->u32Magic != RTSPINLOCK_MAGIC)
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| 127 | {
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| 128 | AssertMsgFailed(("Invalid spinlock %p magic=%#x\n", pThis, pThis->u32Magic));
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| 129 | return VERR_INVALID_PARAMETER;
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| 130 | }
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| 131 |
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| 132 | ASMAtomicIncU32(&pThis->u32Magic);
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| 133 | RTMemFree(pThis);
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| 134 | return VINF_SUCCESS;
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| 135 | }
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| 136 | RT_EXPORT_SYMBOL(RTSpinlockDestroy);
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| 137 |
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| 138 |
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| 139 | RTDECL(void) RTSpinlockAcquire(RTSPINLOCK Spinlock)
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| 140 | {
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| 141 | PRTSPINLOCKINTERNAL pThis = (PRTSPINLOCKINTERNAL)Spinlock;
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| 142 | IPRT_LINUX_SAVE_EFL_AC();
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| 143 | RT_ASSERT_PREEMPT_CPUID_VAR();
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| 144 | AssertMsg(pThis && pThis->u32Magic == RTSPINLOCK_MAGIC,
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| 145 | ("pThis=%p u32Magic=%08x\n", pThis, pThis ? (int)pThis->u32Magic : 0));
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| 146 |
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| 147 | #ifdef CONFIG_PROVE_LOCKING
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| 148 | lockdep_off();
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| 149 | #endif
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| 150 | if (pThis->fFlags & RTSPINLOCK_FLAGS_INTERRUPT_SAFE)
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| 151 | {
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| 152 | unsigned long fIntSaved;
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| 153 | spin_lock_irqsave(&pThis->Spinlock, fIntSaved);
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| 154 | pThis->fIntSaved = fIntSaved;
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| 155 | }
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| 156 | else
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| 157 | spin_lock(&pThis->Spinlock);
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| 158 | #ifdef CONFIG_PROVE_LOCKING
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| 159 | lockdep_on();
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| 160 | #endif
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| 161 |
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| 162 | IPRT_LINUX_RESTORE_EFL_ONLY_AC();
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| 163 | RT_ASSERT_PREEMPT_CPUID_SPIN_ACQUIRED(pThis);
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| 164 | }
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| 165 | RT_EXPORT_SYMBOL(RTSpinlockAcquire);
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| 166 |
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| 167 |
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| 168 | RTDECL(void) RTSpinlockRelease(RTSPINLOCK Spinlock)
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| 169 | {
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| 170 | PRTSPINLOCKINTERNAL pThis = (PRTSPINLOCKINTERNAL)Spinlock;
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| 171 | IPRT_LINUX_SAVE_EFL_AC(); /* spin_unlock* may preempt and trash eflags.ac. */
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| 172 | RT_ASSERT_PREEMPT_CPUID_SPIN_RELEASE_VARS();
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| 173 | AssertMsg(pThis && pThis->u32Magic == RTSPINLOCK_MAGIC,
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| 174 | ("pThis=%p u32Magic=%08x\n", pThis, pThis ? (int)pThis->u32Magic : 0));
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| 175 | RT_ASSERT_PREEMPT_CPUID_SPIN_RELEASE(pThis);
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| 176 |
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| 177 | #ifdef CONFIG_PROVE_LOCKING
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| 178 | lockdep_off();
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| 179 | #endif
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| 180 | if (pThis->fFlags & RTSPINLOCK_FLAGS_INTERRUPT_SAFE)
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| 181 | {
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| 182 | unsigned long fIntSaved = pThis->fIntSaved;
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| 183 | pThis->fIntSaved = 0;
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| 184 | spin_unlock_irqrestore(&pThis->Spinlock, fIntSaved);
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| 185 | }
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| 186 | else
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| 187 | spin_unlock(&pThis->Spinlock);
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| 188 | #ifdef CONFIG_PROVE_LOCKING
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| 189 | lockdep_on();
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| 190 | #endif
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| 191 |
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| 192 | IPRT_LINUX_RESTORE_EFL_ONLY_AC();
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| 193 | RT_ASSERT_PREEMPT_CPUID();
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| 194 | }
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| 195 | RT_EXPORT_SYMBOL(RTSpinlockRelease);
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| 196 |
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