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
  24 void    _ReadWriteBarrier (void);
  25 #pragma intrinsic(_ReadWriteBarrier)
  26
  27
  28 #define SPIN_LOCK_RELEASED          ((UINTN) 1)
  29 #define SPIN_LOCK_ACQUIRED          ((UINTN) 2)
  30
  31 /**
  32   Retrieves the architecture specific spin lock alignment requirements for
  33   optimal spin lock performance.
  34
  35   This function retrieves the spin lock alignment requirements for optimal
  36   performance on a given CPU architecture. The spin lock alignment must be a
  37   power of two and is returned by this function. If there are no alignment
  38   requirements, then 1 must be returned. The spin lock synchronization
  39   functions must function correctly if the spin lock size and alignment values
  40   returned by this function are not used at all. These values are hints to the
  41   consumers of the spin lock synchronization functions to obtain optimal spin
  42   lock performance.
  43
  44   @return The architecture specific spin lock alignment.
  45
  46 **/
  47 UINTN
  48 EFIAPI
  49 GetSpinLockProperties (
  50   VOID
  51   )
  52 {
  53   return 32;
  54 }
  55
  56 /**
  57   Initializes a spin lock to the released state and returns the spin lock.
  58
  59   This function initializes the spin lock specified by SpinLock to the released
  60   state, and returns SpinLock. Optimal performance can be achieved by calling
  61   GetSpinLockProperties() to determine the size and alignment requirements for
  62   SpinLock.
  63
  64   If SpinLock is NULL, then ASSERT().
  65
  66   @param  SpinLock  A pointer to the spin lock to initialize to the released
  67                     state.
  68
  69   @return SpinLock in release state.
  70
  71 **/
  72 SPIN_LOCK *
  73 EFIAPI
  74 InitializeSpinLock (
  75   OUT     SPIN_LOCK                 *SpinLock
  76   )
  77 {
  78   ASSERT (SpinLock != NULL);
  79
  80   _ReadWriteBarrier();
  81   *SpinLock = SPIN_LOCK_RELEASED;
  82   _ReadWriteBarrier();
  83
  84   return SpinLock;
  85 }
  86
  87 /**
  88   Waits until a spin lock can be placed in the acquired state.
  89
  90   This function checks the state of the spin lock specified by SpinLock. If
  91   SpinLock is in the released state, then this function places SpinLock in the
  92   acquired state and returns SpinLock. Otherwise, this function waits
  93   indefinitely for the spin lock to be released, and then places it in the
  94   acquired state and returns SpinLock. All state transitions of SpinLock must
  95   be performed using MP safe mechanisms.
  96
  97   If SpinLock is NULL, then ASSERT().
  98   If SpinLock was not initialized with InitializeSpinLock(), then ASSERT().
  99   If PcdSpinLockTimeout is not zero, and SpinLock is can not be acquired in
 100   PcdSpinLockTimeout microseconds, then ASSERT().
 101
 102   @param  SpinLock  A pointer to the spin lock to place in the acquired state.
 103
 104   @return SpinLock acquired lock.
 105
 106 **/
 107 SPIN_LOCK *
 108 EFIAPI
 109 AcquireSpinLock (
 110   IN OUT  SPIN_LOCK                 *SpinLock
 111   )
 112 {
 113   UINT64  Current;
 114   UINT64  Previous;
 115   UINT64  Total;
 116   UINT64  Start;
 117   UINT64  End;
 118   UINT64  Timeout;
 119   INT64   Cycle;
 120   INT64   Delta;
 121
 122   if (PcdGet32 (PcdSpinLockTimeout) > 0) {
 123     //
 124     // Get the current timer value
 125     //
 126     Current = GetPerformanceCounter();
 127
 128     //
 129     // Initialize local variables
 130     //
 131     Start = 0;
 132     End   = 0;
 133     Total = 0;
 134
 135     //
 136     // Retrieve the performance counter properties and compute the number of performance
 137     // counter ticks required to reach the timeout
 138     //
 139     Timeout = DivU64x32 (
 140                 MultU64x32 (
 141                   GetPerformanceCounterProperties (&Start, &End),
 142                   PcdGet32 (PcdSpinLockTimeout)
 143                   ),
 144                 1000000
 145                 );
 146     Cycle = End - Start;
 147     if (Cycle < 0) {
 148       Cycle = -Cycle;
 149     }
 150     Cycle++;
 151
 152     while (!AcquireSpinLockOrFail (SpinLock)) {
 153       CpuPause ();
 154       Previous = Current;
 155       Current  = GetPerformanceCounter();
 156       Delta = (INT64) (Current - Previous);
 157       if (Start > End) {
 158         Delta = -Delta;
 159       }
 160       if (Delta < 0) {
 161         Delta += Cycle;
 162       }
 163       Total += Delta;
 164       ASSERT (Total < Timeout);
 165     }
 166   } else {
 167     while (!AcquireSpinLockOrFail (SpinLock)) {
 168       CpuPause ();
 169     }
 170   }
 171   return SpinLock;
 172 }
 173
 174 /**
 175   Attempts to place a spin lock in the acquired state.
 176
 177   This function checks the state of the spin lock specified by SpinLock. If
 178   SpinLock is in the released state, then this function places SpinLock in the
 179   acquired state and returns TRUE. Otherwise, FALSE is returned. All state
 180   transitions of SpinLock must be performed using MP safe mechanisms.
 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 place in the acquired state.
 186
 187   @retval TRUE  SpinLock was placed in the acquired state.
 188   @retval FALSE SpinLock could not be acquired.
 189
 190 **/
 191 BOOLEAN
 192 EFIAPI
 193 AcquireSpinLockOrFail (
 194   IN OUT  SPIN_LOCK                 *SpinLock
 195   )
 196 {
 197   SPIN_LOCK   LockValue;
 198   VOID        *Result;
 199
 200   ASSERT (SpinLock != NULL);
 201
 202   LockValue = *SpinLock;
 203   ASSERT (LockValue == SPIN_LOCK_ACQUIRED || LockValue == SPIN_LOCK_RELEASED);
 204
 205   _ReadWriteBarrier ();
 206   Result = InterlockedCompareExchangePointer (
 207              (VOID**)SpinLock,
 208              (VOID*)SPIN_LOCK_RELEASED,
 209              (VOID*)SPIN_LOCK_ACQUIRED
 210            );
 211
 212   _ReadWriteBarrier ();
 213   return (BOOLEAN) (Result == (VOID*) SPIN_LOCK_RELEASED);
 214 }
 215
 216 /**
 217   Releases a spin lock.
 218
 219   This function places the spin lock specified by SpinLock in the release state
 220   and returns SpinLock.
 221
 222   If SpinLock is NULL, then ASSERT().
 223   If SpinLock was not initialized with InitializeSpinLock(), then ASSERT().
 224
 225   @param  SpinLock  A pointer to the spin lock to release.
 226
 227   @return SpinLock released lock.
 228
 229 **/
 230 SPIN_LOCK *
 231 EFIAPI
 232 ReleaseSpinLock (
 233   IN OUT  SPIN_LOCK                 *SpinLock
 234   )
 235 {
 236   SPIN_LOCK    LockValue;
 237
 238   ASSERT (SpinLock != NULL);
 239
 240   LockValue = *SpinLock;
 241   ASSERT (LockValue == SPIN_LOCK_ACQUIRED || LockValue == SPIN_LOCK_RELEASED);
 242
 243   _ReadWriteBarrier ();
 244   *SpinLock = SPIN_LOCK_RELEASED;
 245   _ReadWriteBarrier ();
 246
 247   return SpinLock;
 248 }
 249
 250 /**
 251   Performs an atomic increment of an 32-bit unsigned integer.
 252
 253   Performs an atomic increment of the 32-bit unsigned integer specified by
 254   Value and returns the incremented value. The increment operation must be
 255   performed using MP safe mechanisms. The state of the return value is not
 256   guaranteed to be MP safe.
 257
 258   If Value is NULL, then ASSERT().
 259
 260   @param  Value A pointer to the 32-bit value to increment.
 261
 262   @return The incremented value.
 263
 264 **/
 265 UINT32
 266 EFIAPI
 267 InterlockedIncrement (
 268   IN      UINT32                    *Value
 269   )
 270 {
 271   ASSERT (Value != NULL);
 272   return InternalSyncIncrement (Value);
 273 }
 274
 275 /**
 276   Performs an atomic decrement of an 32-bit unsigned integer.
 277
 278   Performs an atomic decrement of the 32-bit unsigned integer specified by
 279   Value and returns the decremented value. The decrement operation must be
 280   performed using MP safe mechanisms. The state of the return value is not
 281   guaranteed to be MP safe.
 282
 283   If Value is NULL, then ASSERT().
 284
 285   @param  Value A pointer to the 32-bit value to decrement.
 286
 287   @return The decremented value.
 288
 289 **/
 290 UINT32
 291 EFIAPI
 292 InterlockedDecrement (
 293   IN      UINT32                    *Value
 294   )
 295 {
 296   ASSERT (Value != NULL);
 297   return InternalSyncDecrement (Value);
 298 }
 299
 300 /**
 301   Performs an atomic compare exchange operation on a 32-bit unsigned integer.
 302
 303   Performs an atomic compare exchange operation on the 32-bit unsigned integer
 304   specified by Value.  If Value is equal to CompareValue, then Value is set to
 305   ExchangeValue and CompareValue is returned.  If Value is not equal to CompareValue,
 306   then Value is returned.  The compare exchange operation must be performed using
 307   MP safe mechanisms.
 308
 309   If Value is NULL, then ASSERT().
 310
 311   @param  Value         A pointer to the 32-bit value for the compare exchange
 312                         operation.
 313   @param  CompareValue  32-bit value used in compare operation.
 314   @param  ExchangeValue 32-bit value used in exchange operation.
 315
 316   @return The original *Value before exchange.
 317
 318 **/
 319 UINT32
 320 EFIAPI
 321 InterlockedCompareExchange32 (
 322   IN OUT  UINT32                    *Value,
 323   IN      UINT32                    CompareValue,
 324   IN      UINT32                    ExchangeValue
 325   )
 326 {
 327   ASSERT (Value != NULL);
 328   return InternalSyncCompareExchange32 (Value, CompareValue, ExchangeValue);
 329 }
 330
 331 /**
 332   Performs an atomic compare exchange operation on a 64-bit unsigned integer.
 333
 334   Performs an atomic compare exchange operation on the 64-bit unsigned integer specified
 335   by Value.  If Value is equal to CompareValue, then Value is set to ExchangeValue and
 336   CompareValue is returned.  If Value is not equal to CompareValue, then Value is returned.
 337   The compare exchange operation must be performed using MP safe mechanisms.
 338
 339   If Value is NULL, then ASSERT().
 340
 341   @param  Value         A pointer to the 64-bit value for the compare exchange
 342                         operation.
 343   @param  CompareValue  64-bit value used in compare operation.
 344   @param  ExchangeValue 64-bit value used in exchange operation.
 345
 346   @return The original *Value before exchange.
 347
 348 **/
 349 UINT64
 350 EFIAPI
 351 InterlockedCompareExchange64 (
 352   IN OUT  UINT64                    *Value,
 353   IN      UINT64                    CompareValue,
 354   IN      UINT64                    ExchangeValue
 355   )
 356 {
 357   ASSERT (Value != NULL);
 358   return InternalSyncCompareExchange64 (Value, CompareValue, ExchangeValue);
 359 }
 360
 361 /**
 362   Performs an atomic compare exchange operation on a pointer value.
 363
 364   Performs an atomic compare exchange operation on the pointer value specified
 365   by Value. If Value is equal to CompareValue, then Value is set to
 366   ExchangeValue and CompareValue is returned. If Value is not equal to
 367   CompareValue, then Value is returned. The compare exchange operation must be
 368   performed using MP safe mechanisms.
 369
 370   If Value is NULL, then ASSERT().
 371
 372   @param  Value         A pointer to the pointer value for the compare exchange
 373                         operation.
 374   @param  CompareValue  Pointer value used in compare operation.
 375   @param  ExchangeValue Pointer value used in exchange operation.
 376
 377   @return The original *Value before exchange.
 378
 379 **/
 380 VOID *
 381 EFIAPI
 382 InterlockedCompareExchangePointer (
 383   IN OUT  VOID                      **Value,
 384   IN      VOID                      *CompareValue,
 385   IN      VOID                      *ExchangeValue
 386   )
 387 {
 388   UINT8  SizeOfValue;
 389
 390   SizeOfValue = sizeof (*Value);
 391
 392   switch (SizeOfValue) {
 393     case sizeof (UINT32):
 394       return (VOID*)(UINTN)InterlockedCompareExchange32 (
 395                              (UINT32*)Value,
 396                              (UINT32)(UINTN)CompareValue,
 397                              (UINT32)(UINTN)ExchangeValue
 398                              );
 399     case sizeof (UINT64):
 400       return (VOID*)(UINTN)InterlockedCompareExchange64 (
 401                              (UINT64*)Value,
 402                              (UINT64)(UINTN)CompareValue,
 403                              (UINT64)(UINTN)ExchangeValue
 404                              );
 405     default:
 406       ASSERT (FALSE);
 407       return NULL;
 408   }
 409 }