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