MdePkg/Library/BaseSynchronizationLib/SynchronizationGcc.c

   1 /** @file
   2   Implementation of synchronization functions.
   3
   4   Copyright (c) 2006 - 2016, Intel Corporation. All rights reserved.<BR>
   5   Portions copyright (c) 2008 - 2009, Apple Inc. All rights reserved.<BR>
   6   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 is byte alignment.
  32   It must be a 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 InternalGetSpinLockProperties ();
  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 is 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 the 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     while (!AcquireSpinLockOrFail (SpinLock)) {
 119       CpuPause ();
 120     }
 121   } else if (!AcquireSpinLockOrFail (SpinLock)) {
 122     //
 123     // Get the current timer value
 124     //
 125     Current = GetPerformanceCounter();
 126
 127     //
 128     // Initialize local variables
 129     //
 130     Start = 0;
 131     End   = 0;
 132     Total = 0;
 133
 134     //
 135     // Retrieve the performance counter properties and compute the number of performance
 136     // counter ticks required to reach the timeout
 137     //
 138     Timeout = DivU64x32 (
 139                 MultU64x32 (
 140                   GetPerformanceCounterProperties (&Start, &End),
 141                   PcdGet32 (PcdSpinLockTimeout)
 142                   ),
 143                 1000000
 144                 );
 145     Cycle = End - Start;
 146     if (Cycle < 0) {
 147       Cycle = -Cycle;
 148     }
 149     Cycle++;
 150
 151     while (!AcquireSpinLockOrFail (SpinLock)) {
 152       CpuPause ();
 153       Previous = Current;
 154       Current  = GetPerformanceCounter();
 155       Delta = (INT64) (Current - Previous);
 156       if (Start > End) {
 157         Delta = -Delta;
 158       }
 159       if (Delta < 0) {
 160         Delta += Cycle;
 161       }
 162       Total += Delta;
 163       ASSERT (Total < Timeout);
 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 the 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      volatile 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      volatile UINT32           *Value
 289   )
 290 {
 291   ASSERT (Value != NULL);
 292   return InternalSyncDecrement (Value);
 293 }
 294
 295 /**
 296   Performs an atomic compare exchange operation on a 16-bit unsigned integer.
 297
 298   Performs an atomic compare exchange operation on the 16-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 16-bit value for the compare exchange
 307                         operation.
 308   @param  CompareValue  A 16-bit value used in compare operation.
 309   @param  ExchangeValue A 16-bit value used in exchange operation.
 310
 311   @return The original *Value before exchange.
 312
 313 **/
 314 UINT16
 315 EFIAPI
 316 InterlockedCompareExchange16 (
 317   IN OUT  volatile UINT16           *Value,
 318   IN      UINT16                    CompareValue,
 319   IN      UINT16                    ExchangeValue
 320   )
 321 {
 322   ASSERT (Value != NULL);
 323   return InternalSyncCompareExchange16 (Value, CompareValue, ExchangeValue);
 324 }
 325
 326 /**
 327   Performs an atomic compare exchange operation on a 32-bit unsigned integer.
 328
 329   Performs an atomic compare exchange operation on the 32-bit unsigned integer
 330   specified by Value.  If Value is equal to CompareValue, then Value is set to
 331   ExchangeValue and CompareValue is returned.  If Value is not equal to CompareValue,
 332   then Value is returned.  The compare exchange operation must be performed using
 333   MP safe mechanisms.
 334
 335   If Value is NULL, then ASSERT().
 336
 337   @param  Value         A pointer to the 32-bit value for the compare exchange
 338                         operation.
 339   @param  CompareValue  A 32-bit value used in compare operation.
 340   @param  ExchangeValue A 32-bit value used in exchange operation.
 341
 342   @return The original *Value before exchange.
 343
 344 **/
 345 UINT32
 346 EFIAPI
 347 InterlockedCompareExchange32 (
 348   IN OUT  volatile UINT32           *Value,
 349   IN      UINT32                    CompareValue,
 350   IN      UINT32                    ExchangeValue
 351   )
 352 {
 353   ASSERT (Value != NULL);
 354   return InternalSyncCompareExchange32 (Value, CompareValue, ExchangeValue);
 355 }
 356
 357 /**
 358   Performs an atomic compare exchange operation on a 64-bit unsigned integer.
 359
 360   Performs an atomic compare exchange operation on the 64-bit unsigned integer specified
 361   by Value.  If Value is equal to CompareValue, then Value is set to ExchangeValue and
 362   CompareValue is returned.  If Value is not equal to CompareValue, then Value is returned.
 363   The compare exchange operation must be performed using MP safe mechanisms.
 364
 365   If Value is NULL, then ASSERT().
 366
 367   @param  Value         A pointer to the 64-bit value for the compare exchange
 368                         operation.
 369   @param  CompareValue  A 64-bit value used in a compare operation.
 370   @param  ExchangeValue A 64-bit value used in an exchange operation.
 371
 372   @return The original *Value before exchange.
 373
 374 **/
 375 UINT64
 376 EFIAPI
 377 InterlockedCompareExchange64 (
 378   IN OUT  volatile UINT64           *Value,
 379   IN      UINT64                    CompareValue,
 380   IN      UINT64                    ExchangeValue
 381   )
 382 {
 383   ASSERT (Value != NULL);
 384   return InternalSyncCompareExchange64 (Value, CompareValue, ExchangeValue);
 385 }
 386
 387 /**
 388   Performs an atomic compare exchange operation on a pointer value.
 389
 390   Performs an atomic compare exchange operation on the pointer value specified
 391   by Value. If Value is equal to CompareValue, then Value is set to
 392   ExchangeValue and CompareValue is returned. If Value is not equal to
 393   CompareValue, then Value is returned. The compare exchange operation must be
 394   performed using MP safe mechanisms.
 395
 396   If Value is NULL, then ASSERT().
 397
 398   @param  Value         A pointer to the pointer value for the compare exchange
 399                         operation.
 400   @param  CompareValue  A pointer value used in a compare operation.
 401   @param  ExchangeValue A pointer value used in an exchange operation.
 402
 403   @return The original *Value before exchange.
 404 **/
 405 VOID *
 406 EFIAPI
 407 InterlockedCompareExchangePointer (
 408   IN OUT  VOID                      * volatile *Value,
 409   IN      VOID                      *CompareValue,
 410   IN      VOID                      *ExchangeValue
 411   )
 412 {
 413   UINT8  SizeOfValue;
 414
 415   SizeOfValue = sizeof (*Value);
 416
 417   switch (SizeOfValue) {
 418     case sizeof (UINT32):
 419       return (VOID*)(UINTN)InterlockedCompareExchange32 (
 420                              (volatile UINT32 *)Value,
 421                              (UINT32)(UINTN)CompareValue,
 422                              (UINT32)(UINTN)ExchangeValue
 423                              );
 424     case sizeof (UINT64):
 425       return (VOID*)(UINTN)InterlockedCompareExchange64 (
 426                              (volatile UINT64 *)Value,
 427                              (UINT64)(UINTN)CompareValue,
 428                              (UINT64)(UINTN)ExchangeValue
 429                              );
 430     default:
 431       ASSERT (FALSE);
 432       return NULL;
 433   }
 434 }