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)0)
  18 #define SPIN_LOCK_ACQUIRED          ((SPIN_LOCK)-1)
  19
  20 UINT32
  21 EFIAPI
  22 InternalSyncIncrement (
  23   IN      volatile UINT32           *Value
  24   );
  25
  26 UINT32
  27 EFIAPI
  28 InternalSyncDecrement (
  29   IN      volatile UINT32           *Value
  30   );
  31
  32 UINT32
  33 EFIAPI
  34 InternalSyncCompareExchange32 (
  35   IN      volatile UINT32           *Value,
  36   IN      UINT32                    CompareValue,
  37   IN      UINT32                    ExchangeValue
  38   );
  39
  40 UINT64
  41 EFIAPI
  42 InternalSyncCompareExchange64 (
  43   IN      volatile UINT64           *Value,
  44   IN      UINT64                    CompareValue,
  45   IN      UINT64                    ExchangeValue
  46   );
  47
  48 /**
  49   Retrieves the architecture specific spin lock alignment requirements for
  50   optimal spin lock performance.
  51
  52   This function retrieves the spin lock alignment requirements for optimal
  53   performance on a given CPU architecture. The spin lock alignment must be a
  54   power of two and is returned by this function. If there are no alignment
  55   requirements, then 1 must be returned. The spin lock synchronization
  56   functions must function correctly if the spin lock size and alignment values
  57   returned by this function are not used at all. These values are hints to the
  58   consumers of the spin lock synchronization functions to obtain optimal spin
  59   lock performance.
  60
  61   @return The architecture specific spin lock alignment.
  62
  63 **/
  64 UINTN
  65 EFIAPI
  66 GetSpinLockProperties (
  67   VOID
  68   )
  69 {
  70   // @bug May use a PCD entry to determine this alignment.
  71   return 32;
  72 }
  73
  74 /**
  75   Initializes a spin lock to the released state and returns the spin lock.
  76
  77   This function initializes the spin lock specified by SpinLock to the released
  78   state, and returns SpinLock. Optimal performance can be achieved by calling
  79   GetSpinLockProperties() to determine the size and alignment requirements for
  80   SpinLock.
  81
  82   If SpinLock is NULL, then ASSERT().
  83
  84   @param  SpinLock  A pointer to the spin lock to initialize to the released
  85                     state.
  86
  87   @return SpinLock
  88
  89 **/
  90 SPIN_LOCK *
  91 EFIAPI
  92 InitializeSpinLock (
  93   OUT     SPIN_LOCK                 *SpinLock
  94   )
  95 {
  96   ASSERT (SpinLock != NULL);
  97   *SpinLock = 0;
  98   return SpinLock;
  99 }
 100
 101 /**
 102   Waits until a spin lock can be placed in the acquired state.
 103
 104   This function checks the state of the spin lock specified by SpinLock. If
 105   SpinLock is in the released state, then this function places SpinLock in the
 106   acquired state and returns SpinLock. Otherwise, this function waits
 107   indefinitely for the spin lock to be released, and then places it in the
 108   acquired state and returns SpinLock. All state transitions of SpinLock must
 109   be performed using MP safe mechanisms.
 110
 111   If SpinLock is NULL, then ASSERT().
 112   If SpinLock was not initialized with InitializeSpinLock(), then ASSERT().
 113   If PcdSpinLockTimeout is not zero, and SpinLock is can not be acquired in
 114   PcdSpinLockTimeout microseconds, then ASSERT().
 115
 116   @param  SpinLock  A pointer to the spin lock to place in the acquired state.
 117
 118   @return SpinLock
 119
 120 **/
 121 SPIN_LOCK *
 122 EFIAPI
 123 AcquireSpinLock (
 124   IN OUT  SPIN_LOCK                 *SpinLock
 125   )
 126 {
 127   UINT64                            Tick;
 128   UINT64                            Start, End;
 129   UINT64                            Timeout;
 130
 131   Tick = 0;
 132   Start = 0;
 133   End = 0;
 134   if (FixedPcdGet32 (PcdSpinLockTimeout) > 0) {
 135     Tick = GetPerformanceCounter ();
 136     Timeout = DivU64x32 (
 137                 MultU64x32 (
 138                   GetPerformanceCounterProperties (&Start, &End),
 139                   FixedPcdGet32 (PcdSpinLockTimeout)
 140                   ),
 141                 1000000
 142                 );
 143     if (Start < End) {
 144       Tick += Timeout;
 145     } else {
 146       Tick -= Timeout;
 147     }
 148   }
 149
 150   while (!AcquireSpinLockOrFail (SpinLock)) {
 151     CpuPause ();
 152     ASSERT ((Start < End) ^ (Tick <= GetPerformanceCounter ()));
 153   }
 154   return SpinLock;
 155 }
 156
 157 /**
 158   Attempts to place a spin lock in the acquired state.
 159
 160   This function checks the state of the spin lock specified by SpinLock. If
 161   SpinLock is in the released state, then this function places SpinLock in the
 162   acquired state and returns TRUE. Otherwise, FALSE is returned. All state
 163   transitions of SpinLock must be performed using MP safe mechanisms.
 164
 165   If SpinLock is NULL, then ASSERT().
 166   If SpinLock was not initialized with InitializeSpinLock(), then ASSERT().
 167
 168   @param  SpinLock  A pointer to the spin lock to place in the acquired state.
 169
 170   @retval TRUE  SpinLock was placed in the acquired state.
 171   @retval FALSE SpinLock could not be acquired.
 172
 173 **/
 174 BOOLEAN
 175 EFIAPI
 176 AcquireSpinLockOrFail (
 177   IN OUT  SPIN_LOCK                 *SpinLock
 178   )
 179 {
 180   ASSERT (SpinLock != NULL);
 181   return (BOOLEAN)(
 182            InterlockedCompareExchangePointer (
 183              (VOID**)SpinLock,
 184              (VOID*)SPIN_LOCK_RELEASED,
 185              (VOID*)SPIN_LOCK_ACQUIRED
 186              ) == (VOID*)SPIN_LOCK_RELEASED
 187            );
 188 }
 189
 190 /**
 191   Releases a spin lock.
 192
 193   This function places the spin lock specified by SpinLock in the release state
 194   and returns SpinLock.
 195
 196   If SpinLock is NULL, then ASSERT().
 197   If SpinLock was not initialized with InitializeSpinLock(), then ASSERT().
 198
 199   @param  SpinLock  A pointer to the spin lock to release.
 200
 201   @return SpinLock
 202
 203 **/
 204 SPIN_LOCK *
 205 EFIAPI
 206 ReleaseSpinLock (
 207   IN OUT  SPIN_LOCK                 *SpinLock
 208   )
 209 {
 210   ASSERT (SpinLock != NULL);
 211   *SpinLock = 0;
 212   return SpinLock;
 213 }
 214
 215 /**
 216   Performs an atomic increment of an 32-bit unsigned integer.
 217
 218   Performs an atomic increment of the 32-bit unsigned integer specified by
 219   Value and returns the incremented value. The increment operation must be
 220   performed using MP safe mechanisms. The state of the return value is not
 221   guaranteed to be MP safe.
 222
 223   If Value is NULL, then ASSERT().
 224
 225   @param  Value A pointer to the 32-bit value to increment.
 226
 227   @return The incremented value.
 228
 229 **/
 230 UINT32
 231 EFIAPI
 232 InterlockedIncrement (
 233   IN      UINT32                    *Value
 234   )
 235 {
 236   ASSERT (Value != NULL);
 237   return InternalSyncIncrement (Value);
 238 }
 239
 240 /**
 241   Performs an atomic decrement of an 32-bit unsigned integer.
 242
 243   Performs an atomic decrement of the 32-bit unsigned integer specified by
 244   Value and returns the decremented value. The decrement operation must be
 245   performed using MP safe mechanisms. The state of the return value is not
 246   guaranteed to be MP safe.
 247
 248   If Value is NULL, then ASSERT().
 249
 250   @param  Value A pointer to the 32-bit value to decrement.
 251
 252   @return The decremented value.
 253
 254 **/
 255 UINT32
 256 EFIAPI
 257 InterlockedDecrement (
 258   IN      UINT32                    *Value
 259   )
 260 {
 261   ASSERT (Value != NULL);
 262   return InternalSyncDecrement (Value);
 263 }
 264
 265 /**
 266   Performs an atomic compare exchange operation on a 32-bit unsigned integer.
 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      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   @param  Value         A pointer to the 64-bit value for the compare exchange
 292                         operation.
 293   @param  CompareValue  64-bit value used in compare operation.
 294   @param  ExchangeValue 64-bit value used in exchange operation.
 295
 296   @return The original *Value before exchange.
 297
 298 **/
 299 UINT64
 300 EFIAPI
 301 InterlockedCompareExchange64 (
 302   IN      UINT64                    *Value,
 303   IN      UINT64                    CompareValue,
 304   IN      UINT64                    ExchangeValue
 305   )
 306 {
 307   ASSERT (Value != NULL);
 308   return InternalSyncCompareExchange64 (Value, CompareValue, ExchangeValue);
 309 }
 310
 311 /**
 312   Performs an atomic compare exchange operation on a pointer value.
 313
 314   Performs an atomic compare exchange operation on the pointer value specified
 315   by Value. If Value is equal to CompareValue, then Value is set to
 316   ExchangeValue and CompareValue is returned. If Value is not equal to
 317   CompareValue, then Value is returned. The compare exchange operation must be
 318   performed using MP safe mechanisms.
 319
 320   If Value is NULL, then ASSERT().
 321
 322   @param  Value         A pointer to the pointer value for the compare exchange
 323                         operation.
 324   @param  CompareValue  Pointer value used in compare operation.
 325   @param  ExchangeValue Pointer value used in exchange operation.
 326
 327 **/
 328 VOID *
 329 EFIAPI
 330 InterlockedCompareExchangePointer (
 331   IN      VOID                      **Value,
 332   IN      VOID                      *CompareValue,
 333   IN      VOID                      *ExchangeValue
 334   )
 335 {
 336   switch (sizeof (*Value)) {
 337     case sizeof (UINT32):
 338       return (VOID*)(UINTN)InterlockedCompareExchange32 (
 339                              (UINT32*)Value,
 340                              (UINT32)(UINTN)CompareValue,
 341                              (UINT32)(UINTN)ExchangeValue
 342                              );
 343     case sizeof (UINT64):
 344       return (VOID*)(UINTN)InterlockedCompareExchange64 (
 345                              (UINT64*)Value,
 346                              (UINT64)(UINTN)CompareValue,
 347                              (UINT64)(UINTN)ExchangeValue
 348                              );
 349     default:
 350       ASSERT (FALSE);
 351       return NULL;
 352   }
 353 }