MdePkg/Library/BaseLib/Synchronization.c

   1 /** @file
   2   Implementation of synchronization functions.
   3
   4   Copyright (c) 2006, Intel Corporation<BR>
   5   All rights reserved. This program and the accompanying materials
   6   are licensed and made available under the terms and conditions of the BSD License
   7   which accompanies this distribution.  The full text of the license may be found at
   8   http://opensource.org/licenses/bsd-license.php
   9
  10   THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
  11   WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
  12
  13   Module Name:  Synchronization.c
  14
  15 **/
  16
  17 #define SPIN_LOCK_RELEASED          ((SPIN_LOCK)1)
  18 #define SPIN_LOCK_ACQUIRED          ((SPIN_LOCK)2)
  19
  20 /**
  21   Performs an atomic increment of an 32-bit unsigned integer.
  22
  23   Performs an atomic increment of the 32-bit unsigned integer specified by
  24   Value and returns the incremented value. The increment operation must be
  25   performed using MP safe mechanisms. The state of the return value is not
  26   guaranteed to be MP safe.
  27
  28   @param  Value A pointer to the 32-bit value to increment.
  29
  30   @return The incremented value.
  31
  32 **/
  33 UINT32
  34 EFIAPI
  35 InternalSyncIncrement (
  36   IN      volatile UINT32           *Value
  37   );
  38
  39 /**
  40   Performs an atomic decrement of an 32-bit unsigned integer.
  41
  42   Performs an atomic decrement of the 32-bit unsigned integer specified by
  43   Value and returns the decrement value. The decrement operation must be
  44   performed using MP safe mechanisms. The state of the return value is not
  45   guaranteed to be MP safe.
  46
  47   @param  Value A pointer to the 32-bit value to decrement.
  48
  49   @return The decrement value.
  50
  51 **/
  52 UINT32
  53 EFIAPI
  54 InternalSyncDecrement (
  55   IN      volatile UINT32           *Value
  56   );
  57
  58 /**
  59   Performs an atomic compare exchange operation on a 32-bit unsigned integer.
  60
  61   Performs an atomic compare exchange operation on the 32-bit unsigned integer
  62   specified by Value.  If Value is equal to CompareValue, then Value is set to
  63   ExchangeValue and CompareValue is returned.  If Value is not equal to CompareValue,
  64   then Value is returned.  The compare exchange operation must be performed using
  65   MP safe mechanisms.
  66
  67   @param  Value         A pointer to the 32-bit value for the compare exchange
  68                         operation.
  69   @param  CompareValue  32-bit value used in compare operation.
  70   @param  ExchangeValue 32-bit value used in exchange operation.
  71
  72   @return The original *Value before exchange.
  73
  74 **/
  75 UINT32
  76 EFIAPI
  77 InternalSyncCompareExchange32 (
  78   IN      volatile UINT32           *Value,
  79   IN      UINT32                    CompareValue,
  80   IN      UINT32                    ExchangeValue
  81   );
  82
  83 /**
  84   Performs an atomic compare exchange operation on a 64-bit unsigned integer.
  85
  86   Performs an atomic compare exchange operation on the 64-bit unsigned integer specified
  87   by Value.  If Value is equal to CompareValue, then Value is set to ExchangeValue and
  88   CompareValue is returned.  If Value is not equal to CompareValue, then Value is returned.
  89   The compare exchange operation must be performed using MP safe mechanisms.
  90
  91   @param  Value         A pointer to the 64-bit value for the compare exchange
  92                         operation.
  93   @param  CompareValue  64-bit value used in compare operation.
  94   @param  ExchangeValue 64-bit value used in exchange operation.
  95
  96   @return The original *Value before exchange.
  97
  98 **/
  99 UINT64
 100 EFIAPI
 101 InternalSyncCompareExchange64 (
 102   IN      volatile UINT64           *Value,
 103   IN      UINT64                    CompareValue,
 104   IN      UINT64                    ExchangeValue
 105   );
 106
 107 /**
 108   Retrieves the architecture specific spin lock alignment requirements for
 109   optimal spin lock performance.
 110
 111   This function retrieves the spin lock alignment requirements for optimal
 112   performance on a given CPU architecture. The spin lock alignment must be a
 113   power of two and is returned by this function. If there are no alignment
 114   requirements, then 1 must be returned. The spin lock synchronization
 115   functions must function correctly if the spin lock size and alignment values
 116   returned by this function are not used at all. These values are hints to the
 117   consumers of the spin lock synchronization functions to obtain optimal spin
 118   lock performance.
 119
 120   @return The architecture specific spin lock alignment.
 121
 122 **/
 123 UINTN
 124 EFIAPI
 125 GetSpinLockProperties (
 126   VOID
 127   )
 128 {
 129   // @bug May use a PCD entry to determine this alignment.
 130   return 32;
 131 }
 132
 133 /**
 134   Initializes a spin lock to the released state and returns the spin lock.
 135
 136   This function initializes the spin lock specified by SpinLock to the released
 137   state, and returns SpinLock. Optimal performance can be achieved by calling
 138   GetSpinLockProperties() to determine the size and alignment requirements for
 139   SpinLock.
 140
 141   If SpinLock is NULL, then ASSERT().
 142
 143   @param  SpinLock  A pointer to the spin lock to initialize to the released
 144                     state.
 145
 146   @return SpinLock
 147
 148 **/
 149 SPIN_LOCK *
 150 EFIAPI
 151 InitializeSpinLock (
 152   OUT     SPIN_LOCK                 *SpinLock
 153   )
 154 {
 155   ASSERT (SpinLock != NULL);
 156   *SpinLock = SPIN_LOCK_RELEASED;
 157   return SpinLock;
 158 }
 159
 160 /**
 161   Waits until a spin lock can be placed in the acquired state.
 162
 163   This function checks the state of the spin lock specified by SpinLock. If
 164   SpinLock is in the released state, then this function places SpinLock in the
 165   acquired state and returns SpinLock. Otherwise, this function waits
 166   indefinitely for the spin lock to be released, and then places it in the
 167   acquired state and returns SpinLock. All state transitions of SpinLock must
 168   be performed using MP safe mechanisms.
 169
 170   If SpinLock is NULL, then ASSERT().
 171   If SpinLock was not initialized with InitializeSpinLock(), then ASSERT().
 172   If PcdSpinLockTimeout is not zero, and SpinLock is can not be acquired in
 173   PcdSpinLockTimeout microseconds, then ASSERT().
 174
 175   @param  SpinLock  A pointer to the spin lock to place in the acquired state.
 176
 177   @return SpinLock
 178
 179 **/
 180 SPIN_LOCK *
 181 EFIAPI
 182 AcquireSpinLock (
 183   IN OUT  SPIN_LOCK                 *SpinLock
 184   )
 185 {
 186   UINT64                            Tick;
 187   UINT64                            Start, End;
 188   UINT64                            Timeout;
 189
 190   Tick = 0;
 191   Start = 0;
 192   End = 0;
 193   if (PcdGet32 (PcdSpinLockTimeout) > 0) {
 194     Tick = GetPerformanceCounter ();
 195     Timeout = DivU64x32 (
 196                 MultU64x32 (
 197                   GetPerformanceCounterProperties (&Start, &End),
 198                   PcdGet32 (PcdSpinLockTimeout)
 199                   ),
 200                 1000000
 201                 );
 202     if (Start < End) {
 203       Tick += Timeout;
 204     } else {
 205       Tick -= Timeout;
 206     }
 207   }
 208
 209   while (!AcquireSpinLockOrFail (SpinLock)) {
 210     CpuPause ();
 211     ASSERT ((Start < End) ^ (Tick <= GetPerformanceCounter ()));
 212   }
 213   return SpinLock;
 214 }
 215
 216 /**
 217   Attempts to place a spin lock in the acquired state.
 218
 219   This function checks the state of the spin lock specified by SpinLock. If
 220   SpinLock is in the released state, then this function places SpinLock in the
 221   acquired state and returns TRUE. Otherwise, FALSE is returned. All state
 222   transitions of SpinLock must be performed using MP safe mechanisms.
 223
 224   If SpinLock is NULL, then ASSERT().
 225   If SpinLock was not initialized with InitializeSpinLock(), then ASSERT().
 226
 227   @param  SpinLock  A pointer to the spin lock to place in the acquired state.
 228
 229   @retval TRUE  SpinLock was placed in the acquired state.
 230   @retval FALSE SpinLock could not be acquired.
 231
 232 **/
 233 BOOLEAN
 234 EFIAPI
 235 AcquireSpinLockOrFail (
 236   IN OUT  SPIN_LOCK                 *SpinLock
 237   )
 238 {
 239   ASSERT (SpinLock != NULL);
 240   ASSERT (*SpinLock == SPIN_LOCK_ACQUIRED || *SpinLock == SPIN_LOCK_RELEASED);
 241   return (BOOLEAN)(
 242            InterlockedCompareExchangePointer (
 243              (VOID**)SpinLock,
 244              (VOID*)SPIN_LOCK_RELEASED,
 245              (VOID*)SPIN_LOCK_ACQUIRED
 246              ) == (VOID*)SPIN_LOCK_RELEASED
 247            );
 248 }
 249
 250 /**
 251   Releases a spin lock.
 252
 253   This function places the spin lock specified by SpinLock in the release state
 254   and returns SpinLock.
 255
 256   If SpinLock is NULL, then ASSERT().
 257   If SpinLock was not initialized with InitializeSpinLock(), then ASSERT().
 258
 259   @param  SpinLock  A pointer to the spin lock to release.
 260
 261   @return SpinLock
 262
 263 **/
 264 SPIN_LOCK *
 265 EFIAPI
 266 ReleaseSpinLock (
 267   IN OUT  SPIN_LOCK                 *SpinLock
 268   )
 269 {
 270   ASSERT (SpinLock != NULL);
 271   ASSERT (*SpinLock == SPIN_LOCK_ACQUIRED || *SpinLock == SPIN_LOCK_RELEASED);
 272   *SpinLock = SPIN_LOCK_RELEASED;
 273   return SpinLock;
 274 }
 275
 276 /**
 277   Performs an atomic increment of an 32-bit unsigned integer.
 278
 279   Performs an atomic increment of the 32-bit unsigned integer specified by
 280   Value and returns the incremented value. The increment operation must be
 281   performed using MP safe mechanisms. The state of the return value is not
 282   guaranteed to be MP safe.
 283
 284   If Value is NULL, then ASSERT().
 285
 286   @param  Value A pointer to the 32-bit value to increment.
 287
 288   @return The incremented value.
 289
 290 **/
 291 UINT32
 292 EFIAPI
 293 InterlockedIncrement (
 294   IN      UINT32                    *Value
 295   )
 296 {
 297   ASSERT (Value != NULL);
 298   return InternalSyncIncrement (Value);
 299 }
 300
 301 /**
 302   Performs an atomic decrement of an 32-bit unsigned integer.
 303
 304   Performs an atomic decrement of the 32-bit unsigned integer specified by
 305   Value and returns the decremented value. The decrement operation must be
 306   performed using MP safe mechanisms. The state of the return value is not
 307   guaranteed to be MP safe.
 308
 309   If Value is NULL, then ASSERT().
 310
 311   @param  Value A pointer to the 32-bit value to decrement.
 312
 313   @return The decremented value.
 314
 315 **/
 316 UINT32
 317 EFIAPI
 318 InterlockedDecrement (
 319   IN      UINT32                    *Value
 320   )
 321 {
 322   ASSERT (Value != NULL);
 323   return InternalSyncDecrement (Value);
 324 }
 325
 326 /**
 327   Performs an atomic compare exchange operation on a 32-bit unsigned integer.
 328
 329   Performs an atomic compare exchange operation on the 32-bit unsigned integer
 330   specified by Value.  If Value is equal to CompareValue, then Value is set to
 331   ExchangeValue and CompareValue is returned.  If Value is not equal to CompareValue,
 332   then Value is returned.  The compare exchange operation must be performed using
 333   MP safe mechanisms.
 334
 335   If Value is NULL, then ASSERT().
 336
 337   @param  Value         A pointer to the 32-bit value for the compare exchange
 338                         operation.
 339   @param  CompareValue  32-bit value used in compare operation.
 340   @param  ExchangeValue 32-bit value used in exchange operation.
 341
 342   @return The original *Value before exchange.
 343
 344 **/
 345 UINT32
 346 EFIAPI
 347 InterlockedCompareExchange32 (
 348   IN OUT  UINT32                    *Value,
 349   IN      UINT32                    CompareValue,
 350   IN      UINT32                    ExchangeValue
 351   )
 352 {
 353   ASSERT (Value != NULL);
 354   return InternalSyncCompareExchange32 (Value, CompareValue, ExchangeValue);
 355 }
 356
 357 /**
 358   Performs an atomic compare exchange operation on a 64-bit unsigned integer.
 359
 360   Performs an atomic compare exchange operation on the 64-bit unsigned integer specified
 361   by Value.  If Value is equal to CompareValue, then Value is set to ExchangeValue and
 362   CompareValue is returned.  If Value is not equal to CompareValue, then Value is returned.
 363   The compare exchange operation must be performed using MP safe mechanisms.
 364
 365   If Value is NULL, then ASSERT().
 366
 367   @param  Value         A pointer to the 64-bit value for the compare exchange
 368                         operation.
 369   @param  CompareValue  64-bit value used in compare operation.
 370   @param  ExchangeValue 64-bit value used in exchange operation.
 371
 372   @return The original *Value before exchange.
 373
 374 **/
 375 UINT64
 376 EFIAPI
 377 InterlockedCompareExchange64 (
 378   IN OUT  UINT64                    *Value,
 379   IN      UINT64                    CompareValue,
 380   IN      UINT64                    ExchangeValue
 381   )
 382 {
 383   ASSERT (Value != NULL);
 384   return InternalSyncCompareExchange64 (Value, CompareValue, ExchangeValue);
 385 }
 386
 387 /**
 388   Performs an atomic compare exchange operation on a pointer value.
 389
 390   Performs an atomic compare exchange operation on the pointer value specified
 391   by Value. If Value is equal to CompareValue, then Value is set to
 392   ExchangeValue and CompareValue is returned. If Value is not equal to
 393   CompareValue, then Value is returned. The compare exchange operation must be
 394   performed using MP safe mechanisms.
 395
 396   If Value is NULL, then ASSERT().
 397
 398   @param  Value         A pointer to the pointer value for the compare exchange
 399                         operation.
 400   @param  CompareValue  Pointer value used in compare operation.
 401   @param  ExchangeValue Pointer value used in exchange operation.
 402
 403 **/
 404 VOID *
 405 EFIAPI
 406 InterlockedCompareExchangePointer (
 407   IN OUT  VOID                      **Value,
 408   IN      VOID                      *CompareValue,
 409   IN      VOID                      *ExchangeValue
 410   )
 411 {
 412   switch (sizeof (*Value)) {
 413     case sizeof (UINT32):
 414       return (VOID*)(UINTN)InterlockedCompareExchange32 (
 415                              (UINT32*)Value,
 416                              (UINT32)(UINTN)CompareValue,
 417                              (UINT32)(UINTN)ExchangeValue
 418                              );
 419     case sizeof (UINT64):
 420       return (VOID*)(UINTN)InterlockedCompareExchange64 (
 421                              (UINT64*)Value,
 422                              (UINT64)(UINTN)CompareValue,
 423                              (UINT64)(UINTN)ExchangeValue
 424                              );
 425     default:
 426       ASSERT (FALSE);
 427       return NULL;
 428   }
 429 }