MdePkg/Library/BaseSynchronizationLib/SynchronizationGcc.c

   1 /** @file
   2   Implementation of synchronization functions.
   3
   4   Copyright (c) 2006 - 2008, Intel Corporation<BR>
   5   Portions Copyright (c) 2008-2009 Apple Inc.<BR>
   6   All rights reserved. This program and the accompanying materials
   7   are licensed and made available under the terms and conditions of the BSD License
   8   which accompanies this distribution.  The full text of the license may be found at
   9   http://opensource.org/licenses/bsd-license.php
  10
  11   THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
  12   WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
  13
  14 **/
  15
  16 #include "BaseSynchronizationLibInternals.h"
  17
  18 //
  19 // GCC inline assembly for Read Write Barrier
  20 //
  21 #define _ReadWriteBarrier() do { __asm__ __volatile__ ("": : : "memory"); } while(0)
  22
  23 #define SPIN_LOCK_RELEASED          ((UINTN) 1)
  24 #define SPIN_LOCK_ACQUIRED          ((UINTN) 2)
  25
  26 /**
  27   Retrieves the architecture specific spin lock alignment requirements for
  28   optimal spin lock performance.
  29
  30   This function retrieves the spin lock alignment requirements for optimal
  31   performance on a given CPU architecture. The spin lock alignment must be a
  32   power of two and is returned by this function. If there are no alignment
  33   requirements, then 1 must be returned. The spin lock synchronization
  34   functions must function correctly if the spin lock size and alignment values
  35   returned by this function are not used at all. These values are hints to the
  36   consumers of the spin lock synchronization functions to obtain optimal spin
  37   lock performance.
  38
  39   @return The architecture specific spin lock alignment.
  40
  41 **/
  42 UINTN
  43 EFIAPI
  44 GetSpinLockProperties (
  45   VOID
  46   )
  47 {
  48   return 32;
  49 }
  50
  51 /**
  52   Initializes a spin lock to the released state and returns the spin lock.
  53
  54   This function initializes the spin lock specified by SpinLock to the released
  55   state, and returns SpinLock. Optimal performance can be achieved by calling
  56   GetSpinLockProperties() to determine the size and alignment requirements for
  57   SpinLock.
  58
  59   If SpinLock is NULL, then ASSERT().
  60
  61   @param  SpinLock  A pointer to the spin lock to initialize to the released
  62                     state.
  63
  64   @return SpinLock in release state.
  65
  66 **/
  67 SPIN_LOCK *
  68 EFIAPI
  69 InitializeSpinLock (
  70   OUT      SPIN_LOCK                 *SpinLock
  71   )
  72 {
  73   ASSERT (SpinLock != NULL);
  74
  75   _ReadWriteBarrier();
  76   *SpinLock = SPIN_LOCK_RELEASED;
  77   _ReadWriteBarrier();
  78
  79   return SpinLock;
  80 }
  81
  82 /**
  83   Waits until a spin lock can be placed in the acquired state.
  84
  85   This function checks the state of the spin lock specified by SpinLock. If
  86   SpinLock is in the released state, then this function places SpinLock in the
  87   acquired state and returns SpinLock. Otherwise, this function waits
  88   indefinitely for the spin lock to be released, and then places it in the
  89   acquired state and returns SpinLock. All state transitions of SpinLock must
  90   be performed using MP safe mechanisms.
  91
  92   If SpinLock is NULL, then ASSERT().
  93   If SpinLock was not initialized with InitializeSpinLock(), then ASSERT().
  94   If PcdSpinLockTimeout is not zero, and SpinLock is can not be acquired in
  95   PcdSpinLockTimeout microseconds, then ASSERT().
  96
  97   @param  SpinLock  A pointer to the spin lock to place in the acquired state.
  98
  99   @return SpinLock acquired lock.
 100
 101 **/
 102 SPIN_LOCK *
 103 EFIAPI
 104 AcquireSpinLock (
 105   IN OUT  SPIN_LOCK                 *SpinLock
 106   )
 107 {
 108   UINT64  Current;
 109   UINT64  Previous;
 110   UINT64  Total;
 111   UINT64  Start;
 112   UINT64  End;
 113   UINT64  Timeout;
 114   INT64   Cycle;
 115   INT64   Delta;
 116
 117   if (PcdGet32 (PcdSpinLockTimeout) > 0) {
 118     //
 119     // Get the current timer value
 120     //
 121     Current = GetPerformanceCounter();
 122
 123     //
 124     // Initialize local variables
 125     //
 126     Start = 0;
 127     End   = 0;
 128     Total = 0;
 129
 130     //
 131     // Retrieve the performance counter properties and compute the number of performance
 132     // counter ticks required to reach the timeout
 133     //
 134     Timeout = DivU64x32 (
 135                 MultU64x32 (
 136                   GetPerformanceCounterProperties (&Start, &End),
 137                   PcdGet32 (PcdSpinLockTimeout)
 138                   ),
 139                 1000000
 140                 );
 141     Cycle = End - Start;
 142     if (Cycle < 0) {
 143       Cycle = -Cycle;
 144     }
 145     Cycle++;
 146
 147     while (!AcquireSpinLockOrFail (SpinLock)) {
 148       CpuPause ();
 149       Previous = Current;
 150       Current  = GetPerformanceCounter();
 151       Delta = (INT64) (Current - Previous);
 152       if (Start > End) {
 153         Delta = -Delta;
 154       }
 155       if (Delta < 0) {
 156         Delta += Cycle;
 157       }
 158       Total += Delta;
 159       ASSERT (Total < Timeout);
 160     }
 161   } else {
 162     while (!AcquireSpinLockOrFail (SpinLock)) {
 163       CpuPause ();
 164     }
 165   }
 166   return SpinLock;
 167 }
 168
 169 /**
 170   Attempts to place a spin lock in the acquired state.
 171
 172   This function checks the state of the spin lock specified by SpinLock. If
 173   SpinLock is in the released state, then this function places SpinLock in the
 174   acquired state and returns TRUE. Otherwise, FALSE is returned. All state
 175   transitions of SpinLock must be performed using MP safe mechanisms.
 176
 177   If SpinLock is NULL, then ASSERT().
 178   If SpinLock was not initialized with InitializeSpinLock(), then ASSERT().
 179
 180   @param  SpinLock  A pointer to the spin lock to place in the acquired state.
 181
 182   @retval TRUE  SpinLock was placed in the acquired state.
 183   @retval FALSE SpinLock could not be acquired.
 184
 185 **/
 186 BOOLEAN
 187 EFIAPI
 188 AcquireSpinLockOrFail (
 189   IN OUT  SPIN_LOCK                 *SpinLock
 190   )
 191 {
 192   SPIN_LOCK   LockValue;
 193   VOID        *Result;
 194
 195   ASSERT (SpinLock != NULL);
 196
 197   LockValue = *SpinLock;
 198   ASSERT (LockValue == SPIN_LOCK_ACQUIRED || LockValue == SPIN_LOCK_RELEASED);
 199
 200   _ReadWriteBarrier ();
 201   Result = InterlockedCompareExchangePointer (
 202              (VOID**)SpinLock,
 203              (VOID*)SPIN_LOCK_RELEASED,
 204              (VOID*)SPIN_LOCK_ACQUIRED
 205            );
 206
 207   _ReadWriteBarrier ();
 208   return (BOOLEAN) (Result == (VOID*) SPIN_LOCK_RELEASED);
 209 }
 210
 211 /**
 212   Releases a spin lock.
 213
 214   This function places the spin lock specified by SpinLock in the release state
 215   and returns SpinLock.
 216
 217   If SpinLock is NULL, then ASSERT().
 218   If SpinLock was not initialized with InitializeSpinLock(), then ASSERT().
 219
 220   @param  SpinLock  A pointer to the spin lock to release.
 221
 222   @return SpinLock released lock.
 223
 224 **/
 225 SPIN_LOCK *
 226 EFIAPI
 227 ReleaseSpinLock (
 228   IN OUT  SPIN_LOCK                 *SpinLock
 229   )
 230 {
 231   SPIN_LOCK    LockValue;
 232
 233   ASSERT (SpinLock != NULL);
 234
 235   LockValue = *SpinLock;
 236   ASSERT (LockValue == SPIN_LOCK_ACQUIRED || LockValue == SPIN_LOCK_RELEASED);
 237
 238   _ReadWriteBarrier ();
 239   *SpinLock = SPIN_LOCK_RELEASED;
 240   _ReadWriteBarrier ();
 241
 242   return SpinLock;
 243 }
 244
 245 /**
 246   Performs an atomic increment of an 32-bit unsigned integer.
 247
 248   Performs an atomic increment of the 32-bit unsigned integer specified by
 249   Value and returns the incremented value. The increment operation must be
 250   performed using MP safe mechanisms. The state of the return value is not
 251   guaranteed to be MP safe.
 252
 253   If Value is NULL, then ASSERT().
 254
 255   @param  Value A pointer to the 32-bit value to increment.
 256
 257   @return The incremented value.
 258
 259 **/
 260 UINT32
 261 EFIAPI
 262 InterlockedIncrement (
 263   IN      UINT32                    *Value
 264   )
 265 {
 266   ASSERT (Value != NULL);
 267   return InternalSyncIncrement (Value);
 268 }
 269
 270 /**
 271   Performs an atomic decrement of an 32-bit unsigned integer.
 272
 273   Performs an atomic decrement of the 32-bit unsigned integer specified by
 274   Value and returns the decremented value. The decrement operation must be
 275   performed using MP safe mechanisms. The state of the return value is not
 276   guaranteed to be MP safe.
 277
 278   If Value is NULL, then ASSERT().
 279
 280   @param  Value A pointer to the 32-bit value to decrement.
 281
 282   @return The decremented value.
 283
 284 **/
 285 UINT32
 286 EFIAPI
 287 InterlockedDecrement (
 288   IN      UINT32                    *Value
 289   )
 290 {
 291   ASSERT (Value != NULL);
 292   return InternalSyncDecrement (Value);
 293 }
 294
 295 /**
 296   Performs an atomic compare exchange operation on a 32-bit unsigned integer.
 297
 298   Performs an atomic compare exchange operation on the 32-bit unsigned integer
 299   specified by Value.  If Value is equal to CompareValue, then Value is set to
 300   ExchangeValue and CompareValue is returned.  If Value is not equal to CompareValue,
 301   then Value is returned.  The compare exchange operation must be performed using
 302   MP safe mechanisms.
 303
 304   If Value is NULL, then ASSERT().
 305
 306   @param  Value         A pointer to the 32-bit value for the compare exchange
 307                         operation.
 308   @param  CompareValue  32-bit value used in compare operation.
 309   @param  ExchangeValue 32-bit value used in exchange operation.
 310
 311   @return The original *Value before exchange.
 312
 313 **/
 314 UINT32
 315 EFIAPI
 316 InterlockedCompareExchange32 (
 317   IN OUT  UINT32                    *Value,
 318   IN      UINT32                    CompareValue,
 319   IN      UINT32                    ExchangeValue
 320   )
 321 {
 322   ASSERT (Value != NULL);
 323   return InternalSyncCompareExchange32 (Value, CompareValue, ExchangeValue);
 324 }
 325
 326 /**
 327   Performs an atomic compare exchange operation on a 64-bit unsigned integer.
 328
 329   Performs an atomic compare exchange operation on the 64-bit unsigned integer specified
 330   by Value.  If Value is equal to CompareValue, then Value is set to ExchangeValue and
 331   CompareValue is returned.  If Value is not equal to CompareValue, then Value is returned.
 332   The compare exchange operation must be performed using MP safe mechanisms.
 333
 334   If Value is NULL, then ASSERT().
 335
 336   @param  Value         A pointer to the 64-bit value for the compare exchange
 337                         operation.
 338   @param  CompareValue  64-bit value used in compare operation.
 339   @param  ExchangeValue 64-bit value used in exchange operation.
 340
 341   @return The original *Value before exchange.
 342
 343 **/
 344 UINT64
 345 EFIAPI
 346 InterlockedCompareExchange64 (
 347   IN OUT  UINT64                    *Value,
 348   IN      UINT64                    CompareValue,
 349   IN      UINT64                    ExchangeValue
 350   )
 351 {
 352   ASSERT (Value != NULL);
 353   return InternalSyncCompareExchange64 (Value, CompareValue, ExchangeValue);
 354 }
 355
 356 /**
 357   Performs an atomic compare exchange operation on a pointer value.
 358
 359   Performs an atomic compare exchange operation on the pointer value specified
 360   by Value. If Value is equal to CompareValue, then Value is set to
 361   ExchangeValue and CompareValue is returned. If Value is not equal to
 362   CompareValue, then Value is returned. The compare exchange operation must be
 363   performed using MP safe mechanisms.
 364
 365   If Value is NULL, then ASSERT().
 366
 367   @param  Value         A pointer to the pointer value for the compare exchange
 368                         operation.
 369   @param  CompareValue  Pointer value used in compare operation.
 370   @param  ExchangeValue Pointer value used in exchange operation.
 371
 372   @return The original *Value before exchange.
 373 **/
 374 VOID *
 375 EFIAPI
 376 InterlockedCompareExchangePointer (
 377   IN OUT  VOID                      **Value,
 378   IN      VOID                      *CompareValue,
 379   IN      VOID                      *ExchangeValue
 380   )
 381 {
 382   UINT8  SizeOfValue;
 383
 384   SizeOfValue = sizeof (*Value);
 385
 386   switch (SizeOfValue) {
 387     case sizeof (UINT32):
 388       return (VOID*)(UINTN)InterlockedCompareExchange32 (
 389                              (UINT32*)Value,
 390                              (UINT32)(UINTN)CompareValue,
 391                              (UINT32)(UINTN)ExchangeValue
 392                              );
 393     case sizeof (UINT64):
 394       return (VOID*)(UINTN)InterlockedCompareExchange64 (
 395                              (UINT64*)Value,
 396                              (UINT64)(UINTN)CompareValue,
 397                              (UINT64)(UINTN)ExchangeValue
 398                              );
 399     default:
 400       ASSERT (FALSE);
 401       return NULL;
 402   }
 403 }