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