MdePkg/Library/BaseSynchronizationLib/Synchronization.c

   1 /** @file
   2   Implementation of synchronization functions.
   3
   4   Copyright (c) 2006 - 2018, Intel Corporation. All rights reserved.<BR>
   5   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 #include "BaseSynchronizationLibInternals.h"
  16
  17 #define SPIN_LOCK_RELEASED          ((UINTN) 1)
  18 #define SPIN_LOCK_ACQUIRED          ((UINTN) 2)
  19
  20 /**
  21   Retrieves the architecture specific spin lock alignment requirements for
  22   optimal spin lock performance.
  23
  24   This function retrieves the spin lock alignment requirements for optimal
  25   performance on a given CPU architecture. The spin lock alignment is byte alignment.
  26   It must be a power of two and is returned by this function. If there are no alignment
  27   requirements, then 1 must be returned. The spin lock synchronization
  28   functions must function correctly if the spin lock size and alignment values
  29   returned by this function are not used at all. These values are hints to the
  30   consumers of the spin lock synchronization functions to obtain optimal spin
  31   lock performance.
  32
  33   @return The architecture specific spin lock alignment.
  34
  35 **/
  36 UINTN
  37 EFIAPI
  38 GetSpinLockProperties (
  39   VOID
  40   )
  41 {
  42   return 32;
  43 }
  44
  45 /**
  46   Initializes a spin lock to the released state and returns the spin lock.
  47
  48   This function initializes the spin lock specified by SpinLock to the released
  49   state, and returns SpinLock. Optimal performance can be achieved by calling
  50   GetSpinLockProperties() to determine the size and alignment requirements for
  51   SpinLock.
  52
  53   If SpinLock is NULL, then ASSERT().
  54
  55   @param  SpinLock  A pointer to the spin lock to initialize to the released
  56                     state.
  57
  58   @return SpinLock is in release state.
  59
  60 **/
  61 SPIN_LOCK *
  62 EFIAPI
  63 InitializeSpinLock (
  64   OUT      SPIN_LOCK                 *SpinLock
  65   )
  66 {
  67   ASSERT (SpinLock != NULL);
  68   *SpinLock = SPIN_LOCK_RELEASED;
  69   return SpinLock;
  70 }
  71
  72 /**
  73   Waits until a spin lock can be placed in the acquired state.
  74
  75   This function checks the state of the spin lock specified by SpinLock. If
  76   SpinLock is in the released state, then this function places SpinLock in the
  77   acquired state and returns SpinLock. Otherwise, this function waits
  78   indefinitely for the spin lock to be released, and then places it in the
  79   acquired state and returns SpinLock. All state transitions of SpinLock must
  80   be performed using MP safe mechanisms.
  81
  82   If SpinLock is NULL, then ASSERT().
  83   If SpinLock was not initialized with InitializeSpinLock(), then ASSERT().
  84   If PcdSpinLockTimeout is not zero, and SpinLock is can not be acquired in
  85   PcdSpinLockTimeout microseconds, then ASSERT().
  86
  87   @param  SpinLock  A pointer to the spin lock to place in the acquired state.
  88
  89   @return SpinLock acquired the lock.
  90
  91 **/
  92 SPIN_LOCK *
  93 EFIAPI
  94 AcquireSpinLock (
  95   IN OUT  SPIN_LOCK                 *SpinLock
  96   )
  97 {
  98   UINT64  Current;
  99   UINT64  Previous;
 100   UINT64  Total;
 101   UINT64  Start;
 102   UINT64  End;
 103   UINT64  Timeout;
 104   INT64   Cycle;
 105   INT64   Delta;
 106
 107   if (PcdGet32 (PcdSpinLockTimeout) == 0) {
 108     while (!AcquireSpinLockOrFail (SpinLock)) {
 109       CpuPause ();
 110     }
 111   } else if (!AcquireSpinLockOrFail (SpinLock)) {
 112     //
 113     // Get the current timer value
 114     //
 115     Current = GetPerformanceCounter();
 116
 117     //
 118     // Initialize local variables
 119     //
 120     Start = 0;
 121     End   = 0;
 122     Total = 0;
 123
 124     //
 125     // Retrieve the performance counter properties and compute the number of performance
 126     // counter ticks required to reach the timeout
 127     //
 128     Timeout = DivU64x32 (
 129                 MultU64x32 (
 130                   GetPerformanceCounterProperties (&Start, &End),
 131                   PcdGet32 (PcdSpinLockTimeout)
 132                   ),
 133                 1000000
 134                 );
 135     Cycle = End - Start;
 136     if (Cycle < 0) {
 137       Cycle = -Cycle;
 138     }
 139     Cycle++;
 140
 141     while (!AcquireSpinLockOrFail (SpinLock)) {
 142       CpuPause ();
 143       Previous = Current;
 144       Current  = GetPerformanceCounter();
 145       Delta = (INT64) (Current - Previous);
 146       if (Start > End) {
 147         Delta = -Delta;
 148       }
 149       if (Delta < 0) {
 150         Delta += Cycle;
 151       }
 152       Total += Delta;
 153       ASSERT (Total < Timeout);
 154     }
 155   }
 156   return SpinLock;
 157 }
 158
 159 /**
 160   Attempts to place a spin lock in the acquired state.
 161
 162   This function checks the state of the spin lock specified by SpinLock. If
 163   SpinLock is in the released state, then this function places SpinLock in the
 164   acquired state and returns TRUE. Otherwise, FALSE is returned. All state
 165   transitions of SpinLock must be performed using MP safe mechanisms.
 166
 167   If SpinLock is NULL, then ASSERT().
 168   If SpinLock was not initialized with InitializeSpinLock(), then ASSERT().
 169
 170   @param  SpinLock  A pointer to the spin lock to place in the acquired state.
 171
 172   @retval TRUE  SpinLock was placed in the acquired state.
 173   @retval FALSE SpinLock could not be acquired.
 174
 175 **/
 176 BOOLEAN
 177 EFIAPI
 178 AcquireSpinLockOrFail (
 179   IN OUT  SPIN_LOCK                 *SpinLock
 180   )
 181 {
 182   SPIN_LOCK    LockValue;
 183
 184   ASSERT (SpinLock != NULL);
 185
 186   LockValue = *SpinLock;
 187   ASSERT (SPIN_LOCK_ACQUIRED == LockValue || SPIN_LOCK_RELEASED == LockValue);
 188
 189   return (BOOLEAN)(
 190            InterlockedCompareExchangePointer (
 191              (VOID**)SpinLock,
 192              (VOID*)SPIN_LOCK_RELEASED,
 193              (VOID*)SPIN_LOCK_ACQUIRED
 194              ) == (VOID*)SPIN_LOCK_RELEASED
 195            );
 196 }
 197
 198 /**
 199   Releases a spin lock.
 200
 201   This function places the spin lock specified by SpinLock in the release state
 202   and returns SpinLock.
 203
 204   If SpinLock is NULL, then ASSERT().
 205   If SpinLock was not initialized with InitializeSpinLock(), then ASSERT().
 206
 207   @param  SpinLock  A pointer to the spin lock to release.
 208
 209   @return SpinLock released lock.
 210
 211 **/
 212 SPIN_LOCK *
 213 EFIAPI
 214 ReleaseSpinLock (
 215   IN OUT  SPIN_LOCK                 *SpinLock
 216   )
 217 {
 218   SPIN_LOCK    LockValue;
 219
 220   ASSERT (SpinLock != NULL);
 221
 222   LockValue = *SpinLock;
 223   ASSERT (SPIN_LOCK_ACQUIRED == LockValue || SPIN_LOCK_RELEASED == LockValue);
 224
 225   *SpinLock = SPIN_LOCK_RELEASED;
 226   return SpinLock;
 227 }
 228
 229 /**
 230   Performs an atomic increment of an 32-bit unsigned integer.
 231
 232   Performs an atomic increment of the 32-bit unsigned integer specified by
 233   Value and returns the incremented value. The increment operation must be
 234   performed using MP safe mechanisms.
 235
 236   If Value is NULL, then ASSERT().
 237
 238   @param  Value A pointer to the 32-bit value to increment.
 239
 240   @return The incremented value.
 241
 242 **/
 243 UINT32
 244 EFIAPI
 245 InterlockedIncrement (
 246   IN      volatile UINT32           *Value
 247   )
 248 {
 249   ASSERT (Value != NULL);
 250   return InternalSyncIncrement (Value);
 251 }
 252
 253 /**
 254   Performs an atomic decrement of an 32-bit unsigned integer.
 255
 256   Performs an atomic decrement of the 32-bit unsigned integer specified by
 257   Value and returns the decremented value. The decrement operation must be
 258   performed using MP safe mechanisms.
 259
 260   If Value is NULL, then ASSERT().
 261
 262   @param  Value A pointer to the 32-bit value to decrement.
 263
 264   @return The decremented value.
 265
 266 **/
 267 UINT32
 268 EFIAPI
 269 InterlockedDecrement (
 270   IN      volatile UINT32           *Value
 271   )
 272 {
 273   ASSERT (Value != NULL);
 274   return InternalSyncDecrement (Value);
 275 }
 276
 277 /**
 278   Performs an atomic compare exchange operation on a 16-bit unsigned integer.
 279
 280   Performs an atomic compare exchange operation on the 16-bit unsigned integer
 281   specified by Value.  If Value is equal to CompareValue, then Value is set to
 282   ExchangeValue and CompareValue is returned.  If Value is not equal to CompareValue,
 283   then Value is returned.  The compare exchange operation must be performed using
 284   MP safe mechanisms.
 285
 286   If Value is NULL, then ASSERT().
 287
 288   @param  Value         A pointer to the 16-bit value for the compare exchange
 289                         operation.
 290   @param  CompareValue  16-bit value used in compare operation.
 291   @param  ExchangeValue 16-bit value used in exchange operation.
 292
 293   @return The original *Value before exchange.
 294
 295 **/
 296 UINT16
 297 EFIAPI
 298 InterlockedCompareExchange16 (
 299   IN OUT  volatile UINT16           *Value,
 300   IN      UINT16                    CompareValue,
 301   IN      UINT16                    ExchangeValue
 302   )
 303 {
 304   ASSERT (Value != NULL);
 305   return InternalSyncCompareExchange16 (Value, CompareValue, ExchangeValue);
 306 }
 307
 308 /**
 309   Performs an atomic compare exchange operation on a 32-bit unsigned integer.
 310
 311   Performs an atomic compare exchange operation on the 32-bit unsigned integer
 312   specified by Value.  If Value is equal to CompareValue, then Value is set to
 313   ExchangeValue and CompareValue is returned.  If Value is not equal to CompareValue,
 314   then Value is returned.  The compare exchange operation must be performed using
 315   MP safe mechanisms.
 316
 317   If Value is NULL, then ASSERT().
 318
 319   @param  Value         A pointer to the 32-bit value for the compare exchange
 320                         operation.
 321   @param  CompareValue  32-bit value used in compare operation.
 322   @param  ExchangeValue 32-bit value used in exchange operation.
 323
 324   @return The original *Value before exchange.
 325
 326 **/
 327 UINT32
 328 EFIAPI
 329 InterlockedCompareExchange32 (
 330   IN OUT  volatile UINT32           *Value,
 331   IN      UINT32                    CompareValue,
 332   IN      UINT32                    ExchangeValue
 333   )
 334 {
 335   ASSERT (Value != NULL);
 336   return InternalSyncCompareExchange32 (Value, CompareValue, ExchangeValue);
 337 }
 338
 339 /**
 340   Performs an atomic compare exchange operation on a 64-bit unsigned integer.
 341
 342   Performs an atomic compare exchange operation on the 64-bit unsigned integer specified
 343   by Value.  If Value is equal to CompareValue, then Value is set to ExchangeValue and
 344   CompareValue is returned.  If Value is not equal to CompareValue, then Value is returned.
 345   The compare exchange operation must be performed using MP safe mechanisms.
 346
 347   If Value is NULL, then ASSERT().
 348
 349   @param  Value         A pointer to the 64-bit value for the compare exchange
 350                         operation.
 351   @param  CompareValue  64-bit value used in compare operation.
 352   @param  ExchangeValue 64-bit value used in exchange operation.
 353
 354   @return The original *Value before exchange.
 355
 356 **/
 357 UINT64
 358 EFIAPI
 359 InterlockedCompareExchange64 (
 360   IN OUT  volatile UINT64           *Value,
 361   IN      UINT64                    CompareValue,
 362   IN      UINT64                    ExchangeValue
 363   )
 364 {
 365   ASSERT (Value != NULL);
 366   return InternalSyncCompareExchange64 (Value, CompareValue, ExchangeValue);
 367 }
 368
 369 /**
 370   Performs an atomic compare exchange operation on a pointer value.
 371
 372   Performs an atomic compare exchange operation on the pointer value specified
 373   by Value. If Value is equal to CompareValue, then Value is set to
 374   ExchangeValue and CompareValue is returned. If Value is not equal to
 375   CompareValue, then Value is returned. The compare exchange operation must be
 376   performed using MP safe mechanisms.
 377
 378   If Value is NULL, then ASSERT().
 379
 380   @param  Value         A pointer to the pointer value for the compare exchange
 381                         operation.
 382   @param  CompareValue  Pointer value used in compare operation.
 383   @param  ExchangeValue Pointer value used in exchange operation.
 384
 385   @return The original *Value before exchange.
 386 **/
 387 VOID *
 388 EFIAPI
 389 InterlockedCompareExchangePointer (
 390   IN OUT  VOID                      * volatile *Value,
 391   IN      VOID                      *CompareValue,
 392   IN      VOID                      *ExchangeValue
 393   )
 394 {
 395   UINT8  SizeOfValue;
 396
 397   SizeOfValue = sizeof (*Value);
 398
 399   switch (SizeOfValue) {
 400     case sizeof (UINT32):
 401       return (VOID*)(UINTN)InterlockedCompareExchange32 (
 402                              (volatile UINT32 *)Value,
 403                              (UINT32)(UINTN)CompareValue,
 404                              (UINT32)(UINTN)ExchangeValue
 405                              );
 406     case sizeof (UINT64):
 407       return (VOID*)(UINTN)InterlockedCompareExchange64 (
 408                              (volatile UINT64 *)Value,
 409                              (UINT64)(UINTN)CompareValue,
 410                              (UINT64)(UINTN)ExchangeValue
 411                              );
 412     default:
 413       ASSERT (FALSE);
 414       return NULL;
 415   }
 416 }