MdePkg/Library/BaseLib/SynchronizationMsc.c

   1 /** @file
   2   Implementation of synchronization functions.
   3
   4   Copyright (c) 2006 - 2007, 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 **/
  14
  15
  16
  17
  18 #include "BaseLibInternals.h"
  19
  20 /**
  21   Microsoft Visual Studio 7.1 Function Prototypes for read write barrier Intrinsics.
  22 **/
  23 void    _ReadWriteBarrier (void);
  24 #pragma intrinsic(_ReadWriteBarrier)
  25
  26
  27 #define SPIN_LOCK_RELEASED          ((UINTN) 1)
  28 #define SPIN_LOCK_ACQUIRED          ((UINTN) 2)
  29
  30 /**
  31   Retrieves the architecture specific spin lock alignment requirements for
  32   optimal spin lock performance.
  33
  34   This function retrieves the spin lock alignment requirements for optimal
  35   performance on a given CPU architecture. The spin lock alignment must be a
  36   power of two and is returned by this function. If there are no alignment
  37   requirements, then 1 must be returned. The spin lock synchronization
  38   functions must function correctly if the spin lock size and alignment values
  39   returned by this function are not used at all. These values are hints to the
  40   consumers of the spin lock synchronization functions to obtain optimal spin
  41   lock performance.
  42
  43   @return The architecture specific spin lock alignment.
  44
  45 **/
  46 UINTN
  47 EFIAPI
  48 GetSpinLockProperties (
  49   VOID
  50   )
  51 {
  52   return 32;
  53 }
  54
  55 /**
  56   Initializes a spin lock to the released state and returns the spin lock.
  57
  58   This function initializes the spin lock specified by SpinLock to the released
  59   state, and returns SpinLock. Optimal performance can be achieved by calling
  60   GetSpinLockProperties() to determine the size and alignment requirements for
  61   SpinLock.
  62
  63   If SpinLock is NULL, then ASSERT().
  64
  65   @param  SpinLock  A pointer to the spin lock to initialize to the released
  66                     state.
  67
  68   @return SpinLock in released state.
  69
  70 **/
  71 SPIN_LOCK *
  72 EFIAPI
  73 InitializeSpinLock (
  74   OUT     SPIN_LOCK                 *SpinLock
  75   )
  76 {
  77   ASSERT (SpinLock != NULL);
  78
  79   _ReadWriteBarrier();
  80   *SpinLock = SPIN_LOCK_RELEASED;
  81   _ReadWriteBarrier();
  82
  83   return SpinLock;
  84 }
  85
  86 /**
  87   Waits until a spin lock can be placed in the acquired state.
  88
  89   This function checks the state of the spin lock specified by SpinLock. If
  90   SpinLock is in the released state, then this function places SpinLock in the
  91   acquired state and returns SpinLock. Otherwise, this function waits
  92   indefinitely for the spin lock to be released, and then places it in the
  93   acquired state and returns SpinLock. All state transitions of SpinLock must
  94   be performed using MP safe mechanisms.
  95
  96   If SpinLock is NULL, then ASSERT().
  97   If SpinLock was not initialized with InitializeSpinLock(), then ASSERT().
  98   If PcdSpinLockTimeout is not zero, and SpinLock is can not be acquired in
  99   PcdSpinLockTimeout microseconds, then ASSERT().
 100
 101   @param  SpinLock  A pointer to the spin lock to place in the acquired state.
 102
 103   @return SpinLock aquiring lock.
 104
 105 **/
 106 SPIN_LOCK *
 107 EFIAPI
 108 AcquireSpinLock (
 109   IN OUT  SPIN_LOCK                 *SpinLock
 110   )
 111 {
 112   UINT64  Current;
 113   UINT64  Previous;
 114   UINT64  Total;
 115   UINT64  Start;
 116   UINT64  End;
 117   UINT64  Timeout;
 118   INT64   Cycle;
 119   INT64   Delta;
 120
 121   if (PcdGet32 (PcdSpinLockTimeout) > 0) {
 122     //
 123     // Get the current timer value
 124     //
 125     Current = GetPerformanceCounter();
 126
 127     //
 128     // Initialize local variables
 129     //
 130     Start = 0;
 131     End   = 0;
 132     Total = 0;
 133
 134     //
 135     // Retrieve the performance counter properties and compute the number of performance
 136     // counter ticks required to reach the timeout
 137     //
 138     Timeout = DivU64x32 (
 139                 MultU64x32 (
 140                   GetPerformanceCounterProperties (&Start, &End),
 141                   PcdGet32 (PcdSpinLockTimeout)
 142                   ),
 143                 1000000
 144                 );
 145     Cycle = End - Start;
 146     if (Cycle < 0) {
 147       Cycle = -Cycle;
 148     }
 149     Cycle++;
 150
 151     while (!AcquireSpinLockOrFail (SpinLock)) {
 152       CpuPause ();
 153       Previous = Current;
 154       Current  = GetPerformanceCounter();
 155       Delta = (INT64) (Current - Previous);
 156       if (Start > End) {
 157         Delta = -Delta;
 158       }
 159       if (Delta < 0) {
 160         Delta += Cycle;
 161       }
 162       Total += Delta;
 163       ASSERT (Total < Timeout);
 164     }
 165   } else {
 166     while (!AcquireSpinLockOrFail (SpinLock)) {
 167       CpuPause ();
 168     }
 169   }
 170   return SpinLock;
 171 }
 172
 173 /**
 174   Attempts to place a spin lock in the acquired state.
 175
 176   This function checks the state of the spin lock specified by SpinLock. If
 177   SpinLock is in the released state, then this function places SpinLock in the
 178   acquired state and returns TRUE. Otherwise, FALSE is returned. All state
 179   transitions of SpinLock must be performed using MP safe mechanisms.
 180
 181   If SpinLock is NULL, then ASSERT().
 182   If SpinLock was not initialized with InitializeSpinLock(), then ASSERT().
 183
 184   @param  SpinLock  A pointer to the spin lock to place in the acquired state.
 185
 186   @retval TRUE  SpinLock was placed in the acquired state.
 187   @retval FALSE SpinLock could not be acquired.
 188
 189 **/
 190 BOOLEAN
 191 EFIAPI
 192 AcquireSpinLockOrFail (
 193   IN OUT  SPIN_LOCK                 *SpinLock
 194   )
 195 {
 196   SPIN_LOCK   LockValue;
 197   VOID        *Result;
 198
 199   ASSERT (SpinLock != NULL);
 200
 201   LockValue = *SpinLock;
 202   ASSERT (LockValue == SPIN_LOCK_ACQUIRED || LockValue == SPIN_LOCK_RELEASED);
 203
 204   _ReadWriteBarrier ();
 205   Result = InterlockedCompareExchangePointer (
 206              (VOID**)SpinLock,
 207              (VOID*)SPIN_LOCK_RELEASED,
 208              (VOID*)SPIN_LOCK_ACQUIRED
 209            );
 210
 211   _ReadWriteBarrier ();
 212   return (BOOLEAN) (Result == (VOID*) SPIN_LOCK_RELEASED);
 213 }
 214
 215 /**
 216   Releases a spin lock.
 217
 218   This function places the spin lock specified by SpinLock in the release state
 219   and returns SpinLock.
 220
 221   If SpinLock is NULL, then ASSERT().
 222   If SpinLock was not initialized with InitializeSpinLock(), then ASSERT().
 223
 224   @param  SpinLock  A pointer to the spin lock to release.
 225
 226   @return SpinLock releasing lock.
 227
 228 **/
 229 SPIN_LOCK *
 230 EFIAPI
 231 ReleaseSpinLock (
 232   IN OUT  SPIN_LOCK                 *SpinLock
 233   )
 234 {
 235   SPIN_LOCK    LockValue;
 236
 237   ASSERT (SpinLock != NULL);
 238
 239   LockValue = *SpinLock;
 240   ASSERT (LockValue == SPIN_LOCK_ACQUIRED || LockValue == SPIN_LOCK_RELEASED);
 241
 242   _ReadWriteBarrier ();
 243   *SpinLock = SPIN_LOCK_RELEASED;
 244   _ReadWriteBarrier ();
 245
 246   return SpinLock;
 247 }
 248
 249 /**
 250   Performs an atomic increment of an 32-bit unsigned integer.
 251
 252   Performs an atomic increment of the 32-bit unsigned integer specified by
 253   Value and returns the incremented value. The increment operation must be
 254   performed using MP safe mechanisms. The state of the return value is not
 255   guaranteed to be MP safe.
 256
 257   If Value is NULL, then ASSERT().
 258
 259   @param  Value A pointer to the 32-bit value to increment.
 260
 261   @return The incremented value.
 262
 263 **/
 264 UINT32
 265 EFIAPI
 266 InterlockedIncrement (
 267   IN      UINT32                    *Value
 268   )
 269 {
 270   ASSERT (Value != NULL);
 271   return InternalSyncIncrement (Value);
 272 }
 273
 274 /**
 275   Performs an atomic decrement of an 32-bit unsigned integer.
 276
 277   Performs an atomic decrement of the 32-bit unsigned integer specified by
 278   Value and returns the decremented value. The decrement operation must be
 279   performed using MP safe mechanisms. The state of the return value is not
 280   guaranteed to be MP safe.
 281
 282   If Value is NULL, then ASSERT().
 283
 284   @param  Value A pointer to the 32-bit value to decrement.
 285
 286   @return The decremented value.
 287
 288 **/
 289 UINT32
 290 EFIAPI
 291 InterlockedDecrement (
 292   IN      UINT32                    *Value
 293   )
 294 {
 295   ASSERT (Value != NULL);
 296   return InternalSyncDecrement (Value);
 297 }
 298
 299 /**
 300   Performs an atomic compare exchange operation on a 32-bit unsigned integer.
 301
 302   Performs an atomic compare exchange operation on the 32-bit unsigned integer
 303   specified by Value.  If Value is equal to CompareValue, then Value is set to
 304   ExchangeValue and CompareValue is returned.  If Value is not equal to CompareValue,
 305   then Value is returned.  The compare exchange operation must be performed using
 306   MP safe mechanisms.
 307
 308   If Value is NULL, then ASSERT().
 309
 310   @param  Value         A pointer to the 32-bit value for the compare exchange
 311                         operation.
 312   @param  CompareValue  32-bit value used in compare operation.
 313   @param  ExchangeValue 32-bit value used in exchange operation.
 314
 315   @return The original *Value before exchange.
 316
 317 **/
 318 UINT32
 319 EFIAPI
 320 InterlockedCompareExchange32 (
 321   IN OUT  UINT32                    *Value,
 322   IN      UINT32                    CompareValue,
 323   IN      UINT32                    ExchangeValue
 324   )
 325 {
 326   ASSERT (Value != NULL);
 327   return InternalSyncCompareExchange32 (Value, CompareValue, ExchangeValue);
 328 }
 329
 330 /**
 331   Performs an atomic compare exchange operation on a 64-bit unsigned integer.
 332
 333   Performs an atomic compare exchange operation on the 64-bit unsigned integer specified
 334   by Value.  If Value is equal to CompareValue, then Value is set to ExchangeValue and
 335   CompareValue is returned.  If Value is not equal to CompareValue, then Value is returned.
 336   The compare exchange operation must be performed using MP safe mechanisms.
 337
 338   If Value is NULL, then ASSERT().
 339
 340   @param  Value         A pointer to the 64-bit value for the compare exchange
 341                         operation.
 342   @param  CompareValue  64-bit value used in compare operation.
 343   @param  ExchangeValue 64-bit value used in exchange operation.
 344
 345   @return The original *Value before exchange.
 346
 347 **/
 348 UINT64
 349 EFIAPI
 350 InterlockedCompareExchange64 (
 351   IN OUT  UINT64                    *Value,
 352   IN      UINT64                    CompareValue,
 353   IN      UINT64                    ExchangeValue
 354   )
 355 {
 356   ASSERT (Value != NULL);
 357   return InternalSyncCompareExchange64 (Value, CompareValue, ExchangeValue);
 358 }
 359
 360 /**
 361   Performs an atomic compare exchange operation on a pointer value.
 362
 363   Performs an atomic compare exchange operation on the pointer value specified
 364   by Value. If Value is equal to CompareValue, then Value is set to
 365   ExchangeValue and CompareValue is returned. If Value is not equal to
 366   CompareValue, then Value is returned. The compare exchange operation must be
 367   performed using MP safe mechanisms.
 368
 369   If Value is NULL, then ASSERT().
 370
 371   @param  Value         A pointer to the pointer value for the compare exchange
 372                         operation.
 373   @param  CompareValue  Pointer value used in compare operation.
 374   @param  ExchangeValue Pointer value used in exchange operation.
 375
 376   @return The original *Value before exchange.
 377
 378 **/
 379 VOID *
 380 EFIAPI
 381 InterlockedCompareExchangePointer (
 382   IN OUT  VOID                      **Value,
 383   IN      VOID                      *CompareValue,
 384   IN      VOID                      *ExchangeValue
 385   )
 386 {
 387   UINT8  SizeOfValue;
 388
 389   SizeOfValue = sizeof (*Value);
 390
 391   switch (SizeOfValue) {
 392     case sizeof (UINT32):
 393       return (VOID*)(UINTN)InterlockedCompareExchange32 (
 394                              (UINT32*)Value,
 395                              (UINT32)(UINTN)CompareValue,
 396                              (UINT32)(UINTN)ExchangeValue
 397                              );
 398     case sizeof (UINT64):
 399       return (VOID*)(UINTN)InterlockedCompareExchange64 (
 400                              (UINT64*)Value,
 401                              (UINT64)(UINTN)CompareValue,
 402                              (UINT64)(UINTN)ExchangeValue
 403                              );
 404     default:
 405       ASSERT (FALSE);
 406       return NULL;
 407   }
 408 }