1 | /* $Id: spinlock-r0drv-freebsd.c 52618 2014-09-05 12:07:29Z vboxsync $ */
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2 | /** @file
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3 | * IPRT - Spinlocks, Ring-0 Driver, FreeBSD.
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4 | */
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5 |
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6 | /*
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7 | * Copyright (c) 2007 knut st. osmundsen <bird-src-spam@anduin.net>
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8 | *
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9 | * Permission is hereby granted, free of charge, to any person
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10 | * obtaining a copy of this software and associated documentation
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11 | * files (the "Software"), to deal in the Software without
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12 | * restriction, including without limitation the rights to use,
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13 | * copy, modify, merge, publish, distribute, sublicense, and/or sell
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14 | * copies of the Software, and to permit persons to whom the
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15 | * Software is furnished to do so, subject to the following
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16 | * conditions:
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17 | *
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18 | * The above copyright notice and this permission notice shall be
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19 | * included in all copies or substantial portions of the Software.
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20 | *
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21 | * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
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22 | * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
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23 | * OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
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24 | * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
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25 | * HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
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26 | * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
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27 | * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
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28 | * OTHER DEALINGS IN THE SOFTWARE.
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29 | */
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30 |
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31 | /*******************************************************************************
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32 | * Header Files *
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33 | *******************************************************************************/
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34 | #include "the-freebsd-kernel.h"
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35 | #include "internal/iprt.h"
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36 |
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37 | #include <iprt/spinlock.h>
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38 | #include <iprt/err.h>
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39 | #include <iprt/alloc.h>
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40 | #include <iprt/assert.h>
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41 | #include <iprt/asm.h>
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42 | #include <iprt/asm-amd64-x86.h>
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43 | #include <iprt/thread.h>
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44 | #include <iprt/mp.h>
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45 |
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46 | #include "internal/magics.h"
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47 |
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48 |
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49 | /*******************************************************************************
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50 | * Structures and Typedefs *
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51 | *******************************************************************************/
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52 | /**
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53 | * Wrapper for the struct mtx type.
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54 | */
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55 | typedef struct RTSPINLOCKINTERNAL
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56 | {
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57 | /** Spinlock magic value (RTSPINLOCK_MAGIC). */
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58 | uint32_t volatile u32Magic;
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59 | /** The spinlock. */
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60 | uint32_t volatile fLocked;
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61 | /** Saved interrupt flag. */
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62 | uint32_t volatile fIntSaved;
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63 | /** The spinlock creation flags. */
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64 | uint32_t fFlags;
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65 | #ifdef RT_MORE_STRICT
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66 | /** The idAssertCpu variable before acquring the lock for asserting after
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67 | * releasing the spinlock. */
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68 | RTCPUID volatile idAssertCpu;
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69 | /** The CPU that owns the lock. */
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70 | RTCPUID volatile idCpuOwner;
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71 | #endif
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72 | } RTSPINLOCKINTERNAL, *PRTSPINLOCKINTERNAL;
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73 |
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74 |
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75 | RTDECL(int) RTSpinlockCreate(PRTSPINLOCK pSpinlock, uint32_t fFlags, const char *pszName)
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76 | {
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77 | RT_ASSERT_PREEMPTIBLE();
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78 | AssertReturn(fFlags == RTSPINLOCK_FLAGS_INTERRUPT_SAFE || fFlags == RTSPINLOCK_FLAGS_INTERRUPT_UNSAFE, VERR_INVALID_PARAMETER);
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79 |
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80 | /*
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81 | * Allocate.
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82 | */
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83 | AssertCompile(sizeof(RTSPINLOCKINTERNAL) > sizeof(void *));
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84 | PRTSPINLOCKINTERNAL pThis = (PRTSPINLOCKINTERNAL)RTMemAllocZ(sizeof(*pThis));
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85 | if (!pThis)
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86 | return VERR_NO_MEMORY;
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87 |
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88 | /*
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89 | * Initialize & return.
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90 | */
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91 | pThis->u32Magic = RTSPINLOCK_MAGIC;
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92 | pThis->fLocked = 0;
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93 | pThis->fFlags = fFlags;
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94 | pThis->fIntSaved = 0;
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95 |
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96 | *pSpinlock = pThis;
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97 | return VINF_SUCCESS;
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98 | }
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99 |
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100 |
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101 | RTDECL(int) RTSpinlockDestroy(RTSPINLOCK Spinlock)
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102 | {
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103 | /*
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104 | * Validate input.
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105 | */
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106 | RT_ASSERT_INTS_ON();
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107 | PRTSPINLOCKINTERNAL pThis = (PRTSPINLOCKINTERNAL)Spinlock;
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108 | if (!pThis)
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109 | return VERR_INVALID_PARAMETER;
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110 | AssertMsgReturn(pThis->u32Magic == RTSPINLOCK_MAGIC,
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111 | ("Invalid spinlock %p magic=%#x\n", pThis, pThis->u32Magic),
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112 | VERR_INVALID_PARAMETER);
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113 |
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114 | /*
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115 | * Make the lock invalid and release the memory.
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116 | */
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117 | ASMAtomicIncU32(&pThis->u32Magic);
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118 | RTMemFree(pThis);
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119 | return VINF_SUCCESS;
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120 | }
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121 |
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122 |
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123 | RTDECL(void) RTSpinlockAcquire(RTSPINLOCK Spinlock)
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124 | {
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125 | PRTSPINLOCKINTERNAL pThis = (PRTSPINLOCKINTERNAL)Spinlock;
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126 | RT_ASSERT_PREEMPT_CPUID_VAR();
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127 | AssertPtr(pThis);
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128 | Assert(pThis->u32Magic == RTSPINLOCK_MAGIC);
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129 |
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130 | if (pThis->fFlags & RTSPINLOCK_FLAGS_INTERRUPT_SAFE)
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131 | {
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132 | for (;;)
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133 | {
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134 | uint32_t fIntSaved = ASMIntDisableFlags();
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135 | critical_enter();
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136 |
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137 | int c = 50;
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138 | for (;;)
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139 | {
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140 | if (ASMAtomicCmpXchgU32(&pThis->fLocked, 1, 0))
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141 | {
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142 | RT_ASSERT_PREEMPT_CPUID_SPIN_ACQUIRED(pThis);
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143 | pThis->fIntSaved = fIntSaved;
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144 | return;
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145 | }
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146 | if (--c <= 0)
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147 | break;
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148 | cpu_spinwait();
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149 | }
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150 |
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151 | /* Enable interrupts while we sleep. */
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152 | ASMSetFlags(fIntSaved);
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153 | critical_exit();
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154 | DELAY(1);
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155 | }
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156 | }
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157 | else
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158 | {
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159 | for (;;)
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160 | {
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161 | critical_enter();
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162 |
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163 | int c = 50;
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164 | for (;;)
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165 | {
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166 | if (ASMAtomicCmpXchgU32(&pThis->fLocked, 1, 0))
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167 | {
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168 | RT_ASSERT_PREEMPT_CPUID_SPIN_ACQUIRED(pThis);
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169 | return;
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170 | }
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171 | if (--c <= 0)
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172 | break;
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173 | cpu_spinwait();
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174 | }
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175 |
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176 | critical_exit();
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177 | DELAY(1);
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178 | }
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179 | }
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180 | }
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181 |
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182 |
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183 | RTDECL(void) RTSpinlockRelease(RTSPINLOCK Spinlock)
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184 | {
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185 | PRTSPINLOCKINTERNAL pThis = (PRTSPINLOCKINTERNAL)Spinlock;
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186 | RT_ASSERT_PREEMPT_CPUID_SPIN_RELEASE_VARS();
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187 |
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188 | AssertPtr(pThis);
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189 | Assert(pThis->u32Magic == RTSPINLOCK_MAGIC);
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190 | RT_ASSERT_PREEMPT_CPUID_SPIN_RELEASE(pThis);
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191 |
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192 | if (pThis->fFlags & RTSPINLOCK_FLAGS_INTERRUPT_SAFE)
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193 | {
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194 | uint32_t fIntSaved = pThis->fIntSaved;
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195 | pThis->fIntSaved = 0;
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196 | if (ASMAtomicCmpXchgU32(&pThis->fLocked, 0, 1))
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197 | ASMSetFlags(fIntSaved);
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198 | else
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199 | AssertMsgFailed(("Spinlock %p was not locked!\n", pThis));
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200 | }
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201 | else
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202 | {
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203 | if (!ASMAtomicCmpXchgU32(&pThis->fLocked, 0, 1))
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204 | AssertMsgFailed(("Spinlock %p was not locked!\n", pThis));
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205 | }
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206 |
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207 | critical_exit();
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208 | }
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209 |
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