1 /*++ 2 3 Copyright (c) 2004 - 2006, Intel Corporation. All rights reserved.<BR> 4 This program and the accompanying materials 5 are licensed and made available under the terms and conditions of the BSD License 6 which accompanies this distribution. The full text of the license may be found at 7 http://opensource.org/licenses/bsd-license.php 8 9 THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS, 10 WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED. 11 12 13 Module Name: 14 15 Synchronization.c 16 17 Abstract: 18 19 Implementation of synchronization functions. 20 21 --*/ 22 23 #include "BaseLibInternals.h" 24 25 #define SPIN_LOCK_RELEASED ((UINTN) 1) 26 #define SPIN_LOCK_ACQUIRED ((UINTN) 2) 27 28 /** 29 Retrieves the architecture specific spin lock alignment requirements for 30 optimal spin lock performance. 31 32 This function retrieves the spin lock alignment requirements for optimal 33 performance on a given CPU architecture. The spin lock alignment must be a 34 power of two and is returned by this function. If there are no alignment 35 requirements, then 1 must be returned. The spin lock synchronization 36 functions must function correctly if the spin lock size and alignment values 37 returned by this function are not used at all. These values are hints to the 38 consumers of the spin lock synchronization functions to obtain optimal spin 39 lock performance. 40 41 @return The architecture specific spin lock alignment. 42 43 **/ 44 UINTN 45 EFIAPI 46 GetSpinLockProperties ( 47 VOID 48 ) 49 { 50 // @bug May use a PCD entry to determine this alignment. 51 return 32; 52 } 53 54 /** 55 Initializes a spin lock to the released state and returns the spin lock. 56 57 This function initializes the spin lock specified by SpinLock to the released 58 state, and returns SpinLock. Optimal performance can be achieved by calling 59 GetSpinLockProperties() to determine the size and alignment requirements for 60 SpinLock. 61 62 If SpinLock is NULL, then ASSERT(). 63 64 @param SpinLock A pointer to the spin lock to initialize to the released 65 state. 66 67 @return SpinLock 68 69 **/ 70 SPIN_LOCK * 71 EFIAPI 72 InitializeSpinLock ( 73 OUT SPIN_LOCK *SpinLock 74 ) 75 { 76 ASSERT (SpinLock != NULL); 77 *SpinLock = SPIN_LOCK_RELEASED; 78 return SpinLock; 79 } 80 81 /** 82 Waits until a spin lock can be placed in the acquired state. 83 84 This function checks the state of the spin lock specified by SpinLock. If 85 SpinLock is in the released state, then this function places SpinLock in the 86 acquired state and returns SpinLock. Otherwise, this function waits 87 indefinitely for the spin lock to be released, and then places it in the 88 acquired state and returns SpinLock. All state transitions of SpinLock must 89 be performed using MP safe mechanisms. 90 91 If SpinLock is NULL, then ASSERT(). 92 If SpinLock was not initialized with InitializeSpinLock(), then ASSERT(). 93 If PcdSpinLockTimeout is not zero, and SpinLock is can not be acquired in 94 PcdSpinLockTimeout microseconds, then ASSERT(). 95 96 @param SpinLock A pointer to the spin lock to place in the acquired state. 97 98 @return SpinLock 99 100 **/ 101 SPIN_LOCK * 102 EFIAPI 103 AcquireSpinLock ( 104 IN OUT SPIN_LOCK *SpinLock 105 ) 106 { 107 UINT64 Tick; 108 UINT64 Start, End; 109 UINT64 Timeout; 110 111 Tick = 0; 112 Start = 0; 113 End = 0; 114 if (PcdGet32 (PcdSpinLockTimeout) > 0) { 115 Tick = GetPerformanceCounter (); 116 Timeout = DivU64x32 ( 117 MultU64x32 ( 118 GetPerformanceCounterProperties (&Start, &End), 119 PcdGet32 (PcdSpinLockTimeout) 120 ), 121 1000000 122 ); 123 if (Start < End) { 124 Tick += Timeout; 125 } else { 126 Tick -= Timeout; 127 } 128 } 129 130 while (!AcquireSpinLockOrFail (SpinLock)) { 131 CpuPause (); 132 ASSERT ((Start < End) ^ (Tick <= GetPerformanceCounter ())); 133 } 134 return SpinLock; 135 } 136 137 /** 138 Attempts to place a spin lock in the acquired state. 139 140 This function checks the state of the spin lock specified by SpinLock. If 141 SpinLock is in the released state, then this function places SpinLock in the 142 acquired state and returns TRUE. Otherwise, FALSE is returned. All state 143 transitions of SpinLock must be performed using MP safe mechanisms. 144 145 If SpinLock is NULL, then ASSERT(). 146 If SpinLock was not initialized with InitializeSpinLock(), then ASSERT(). 147 148 @param SpinLock A pointer to the spin lock to place in the acquired state. 149 150 @retval TRUE SpinLock was placed in the acquired state. 151 @retval FALSE SpinLock could not be acquired. 152 153 **/ 154 BOOLEAN 155 EFIAPI 156 AcquireSpinLockOrFail ( 157 IN OUT SPIN_LOCK *SpinLock 158 ) 159 { 160 SPIN_LOCK LockValue; 161 162 ASSERT (SpinLock != NULL); 163 164 LockValue = *SpinLock; 165 ASSERT (LockValue == SPIN_LOCK_ACQUIRED || LockValue == SPIN_LOCK_RELEASED); 166 167 return (BOOLEAN)( 168 InterlockedCompareExchangePointer ( 169 (VOID**)SpinLock, 170 (VOID*)SPIN_LOCK_RELEASED, 171 (VOID*)SPIN_LOCK_ACQUIRED 172 ) == (VOID*)SPIN_LOCK_RELEASED 173 ); 174 } 175 176 /** 177 Releases a spin lock. 178 179 This function places the spin lock specified by SpinLock in the release state 180 and returns SpinLock. 181 182 If SpinLock is NULL, then ASSERT(). 183 If SpinLock was not initialized with InitializeSpinLock(), then ASSERT(). 184 185 @param SpinLock A pointer to the spin lock to release. 186 187 @return SpinLock 188 189 **/ 190 SPIN_LOCK * 191 EFIAPI 192 ReleaseSpinLock ( 193 IN OUT SPIN_LOCK *SpinLock 194 ) 195 { 196 SPIN_LOCK LockValue; 197 198 ASSERT (SpinLock != NULL); 199 200 LockValue = *SpinLock; 201 ASSERT (LockValue == SPIN_LOCK_ACQUIRED || LockValue == SPIN_LOCK_RELEASED); 202 203 *SpinLock = SPIN_LOCK_RELEASED; 204 return SpinLock; 205 } 206 207 /** 208 Performs an atomic increment of an 32-bit unsigned integer. 209 210 Performs an atomic increment of the 32-bit unsigned integer specified by 211 Value and returns the incremented value. The increment operation must be 212 performed using MP safe mechanisms. The state of the return value is not 213 guaranteed to be MP safe. 214 215 If Value is NULL, then ASSERT(). 216 217 @param Value A pointer to the 32-bit value to increment. 218 219 @return The incremented value. 220 221 **/ 222 UINT32 223 EFIAPI 224 InterlockedIncrement ( 225 IN UINT32 *Value 226 ) 227 { 228 ASSERT (Value != NULL); 229 return InternalSyncIncrement (Value); 230 } 231 232 /** 233 Performs an atomic decrement of an 32-bit unsigned integer. 234 235 Performs an atomic decrement of the 32-bit unsigned integer specified by 236 Value and returns the decremented value. The decrement operation must be 237 performed using MP safe mechanisms. The state of the return value is not 238 guaranteed to be MP safe. 239 240 If Value is NULL, then ASSERT(). 241 242 @param Value A pointer to the 32-bit value to decrement. 243 244 @return The decremented value. 245 246 **/ 247 UINT32 248 EFIAPI 249 InterlockedDecrement ( 250 IN UINT32 *Value 251 ) 252 { 253 ASSERT (Value != NULL); 254 return InternalSyncDecrement (Value); 255 } 256 257 /** 258 Performs an atomic compare exchange operation on a 32-bit unsigned integer. 259 260 Performs an atomic compare exchange operation on the 32-bit unsigned integer 261 specified by Value. If Value is equal to CompareValue, then Value is set to 262 ExchangeValue and CompareValue is returned. If Value is not equal to CompareValue, 263 then Value is returned. The compare exchange operation must be performed using 264 MP safe mechanisms. 265 266 If Value is NULL, then ASSERT(). 267 268 @param Value A pointer to the 32-bit value for the compare exchange 269 operation. 270 @param CompareValue 32-bit value used in compare operation. 271 @param ExchangeValue 32-bit value used in exchange operation. 272 273 @return The original *Value before exchange. 274 275 **/ 276 UINT32 277 EFIAPI 278 InterlockedCompareExchange32 ( 279 IN OUT UINT32 *Value, 280 IN UINT32 CompareValue, 281 IN UINT32 ExchangeValue 282 ) 283 { 284 ASSERT (Value != NULL); 285 return InternalSyncCompareExchange32 (Value, CompareValue, ExchangeValue); 286 } 287 288 /** 289 Performs an atomic compare exchange operation on a 64-bit unsigned integer. 290 291 Performs an atomic compare exchange operation on the 64-bit unsigned integer specified 292 by Value. If Value is equal to CompareValue, then Value is set to ExchangeValue and 293 CompareValue is returned. If Value is not equal to CompareValue, then Value is returned. 294 The compare exchange operation must be performed using MP safe mechanisms. 295 296 If Value is NULL, then ASSERT(). 297 298 @param Value A pointer to the 64-bit value for the compare exchange 299 operation. 300 @param CompareValue 64-bit value used in compare operation. 301 @param ExchangeValue 64-bit value used in exchange operation. 302 303 @return The original *Value before exchange. 304 305 **/ 306 UINT64 307 EFIAPI 308 InterlockedCompareExchange64 ( 309 IN OUT UINT64 *Value, 310 IN UINT64 CompareValue, 311 IN UINT64 ExchangeValue 312 ) 313 { 314 ASSERT (Value != NULL); 315 return InternalSyncCompareExchange64 (Value, CompareValue, ExchangeValue); 316 } 317 318 /** 319 Performs an atomic compare exchange operation on a pointer value. 320 321 Performs an atomic compare exchange operation on the pointer value specified 322 by Value. If Value is equal to CompareValue, then Value is set to 323 ExchangeValue and CompareValue is returned. If Value is not equal to 324 CompareValue, then Value is returned. The compare exchange operation must be 325 performed using MP safe mechanisms. 326 327 If Value is NULL, then ASSERT(). 328 329 @param Value A pointer to the pointer value for the compare exchange 330 operation. 331 @param CompareValue Pointer value used in compare operation. 332 @param ExchangeValue Pointer value used in exchange operation. 333 334 **/ 335 VOID * 336 EFIAPI 337 InterlockedCompareExchangePointer ( 338 IN OUT VOID **Value, 339 IN VOID *CompareValue, 340 IN VOID *ExchangeValue 341 ) 342 { 343 UINT8 SizeOfValue; 344 345 SizeOfValue = sizeof (*Value); 346 347 switch (SizeOfValue) { 348 case sizeof (UINT32): 349 return (VOID*)(UINTN)InterlockedCompareExchange32 ( 350 (UINT32*)Value, 351 (UINT32)(UINTN)CompareValue, 352 (UINT32)(UINTN)ExchangeValue 353 ); 354 case sizeof (UINT64): 355 return (VOID*)(UINTN)InterlockedCompareExchange64 ( 356 (UINT64*)Value, 357 (UINT64)(UINTN)CompareValue, 358 (UINT64)(UINTN)ExchangeValue 359 ); 360 default: 361 ASSERT (FALSE); 362 return NULL; 363 } 364 } 365
