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