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git.proxmox.com Git - mirror_edk2.git/blob - MdePkg/Library/BaseLib/SynchronizationGcc.c
2 Implementation of synchronization functions.
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
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.
13 Module Name: SynchronizationGcc.c
18 // Include common header file for this module.
22 #include "BaseLibInternals.h"
25 // GCC inline assembly for Read Write Barrier
27 #define _ReadWriteBarrier() do { asm volatile ("": : : "memory"); } while(0)
29 #define SPIN_LOCK_RELEASED ((UINTN) 1)
30 #define SPIN_LOCK_ACQUIRED ((UINTN) 2)
33 Retrieves the architecture specific spin lock alignment requirements for
34 optimal spin lock performance.
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
45 @return The architecture specific spin lock alignment.
50 GetSpinLockProperties (
54 // @bug May use a PCD entry to determine this alignment.
59 Initializes a spin lock to the released state and returns the spin lock.
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
66 If SpinLock is NULL, then ASSERT().
68 @param SpinLock A pointer to the spin lock to initialize to the released
77 OUT SPIN_LOCK
*SpinLock
80 ASSERT (SpinLock
!= NULL
);
83 *SpinLock
= SPIN_LOCK_RELEASED
;
90 Waits until a spin lock can be placed in the acquired state.
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.
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().
104 @param SpinLock A pointer to the spin lock to place in the acquired state.
112 IN OUT SPIN_LOCK
*SpinLock
122 if (PcdGet32 (PcdSpinLockTimeout
) > 0) {
123 Tick
= GetPerformanceCounter ();
124 Timeout
= DivU64x32 (
126 GetPerformanceCounterProperties (&Start
, &End
),
127 PcdGet32 (PcdSpinLockTimeout
)
138 while (!AcquireSpinLockOrFail (SpinLock
)) {
140 ASSERT ((Start
< End
) ^ (Tick
<= GetPerformanceCounter ()));
146 Attempts to place a spin lock in the acquired state.
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.
153 If SpinLock is NULL, then ASSERT().
154 If SpinLock was not initialized with InitializeSpinLock(), then ASSERT().
156 @param SpinLock A pointer to the spin lock to place in the acquired state.
158 @retval TRUE SpinLock was placed in the acquired state.
159 @retval FALSE SpinLock could not be acquired.
164 AcquireSpinLockOrFail (
165 IN OUT SPIN_LOCK
*SpinLock
171 ASSERT (SpinLock
!= NULL
);
173 LockValue
= *SpinLock
;
174 ASSERT (LockValue
== SPIN_LOCK_ACQUIRED
|| LockValue
== SPIN_LOCK_RELEASED
);
176 _ReadWriteBarrier ();
177 Result
= InterlockedCompareExchangePointer (
179 (VOID
*)SPIN_LOCK_RELEASED
,
180 (VOID
*)SPIN_LOCK_ACQUIRED
183 _ReadWriteBarrier ();
184 return (BOOLEAN
) (Result
== (VOID
*) SPIN_LOCK_RELEASED
);
188 Releases a spin lock.
190 This function places the spin lock specified by SpinLock in the release state
191 and returns SpinLock.
193 If SpinLock is NULL, then ASSERT().
194 If SpinLock was not initialized with InitializeSpinLock(), then ASSERT().
196 @param SpinLock A pointer to the spin lock to release.
204 IN OUT SPIN_LOCK
*SpinLock
209 ASSERT (SpinLock
!= NULL
);
211 LockValue
= *SpinLock
;
212 ASSERT (LockValue
== SPIN_LOCK_ACQUIRED
|| LockValue
== SPIN_LOCK_RELEASED
);
214 _ReadWriteBarrier ();
215 *SpinLock
= SPIN_LOCK_RELEASED
;
216 _ReadWriteBarrier ();
222 Performs an atomic increment of an 32-bit unsigned integer.
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.
229 If Value is NULL, then ASSERT().
231 @param Value A pointer to the 32-bit value to increment.
233 @return The incremented value.
238 InterlockedIncrement (
242 ASSERT (Value
!= NULL
);
243 return InternalSyncIncrement (Value
);
247 Performs an atomic decrement of an 32-bit unsigned integer.
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.
254 If Value is NULL, then ASSERT().
256 @param Value A pointer to the 32-bit value to decrement.
258 @return The decremented value.
263 InterlockedDecrement (
267 ASSERT (Value
!= NULL
);
268 return InternalSyncDecrement (Value
);
272 Performs an atomic compare exchange operation on a 32-bit unsigned integer.
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
280 If Value is NULL, then ASSERT().
282 @param Value A pointer to the 32-bit value for the compare exchange
284 @param CompareValue 32-bit value used in compare operation.
285 @param ExchangeValue 32-bit value used in exchange operation.
287 @return The original *Value before exchange.
292 InterlockedCompareExchange32 (
293 IN OUT UINT32
*Value
,
294 IN UINT32 CompareValue
,
295 IN UINT32 ExchangeValue
298 ASSERT (Value
!= NULL
);
299 return InternalSyncCompareExchange32 (Value
, CompareValue
, ExchangeValue
);
303 Performs an atomic compare exchange operation on a 64-bit unsigned integer.
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.
310 If Value is NULL, then ASSERT().
312 @param Value A pointer to the 64-bit value for the compare exchange
314 @param CompareValue 64-bit value used in compare operation.
315 @param ExchangeValue 64-bit value used in exchange operation.
317 @return The original *Value before exchange.
322 InterlockedCompareExchange64 (
323 IN OUT UINT64
*Value
,
324 IN UINT64 CompareValue
,
325 IN UINT64 ExchangeValue
328 ASSERT (Value
!= NULL
);
329 return InternalSyncCompareExchange64 (Value
, CompareValue
, ExchangeValue
);
333 Performs an atomic compare exchange operation on a pointer value.
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.
341 If Value is NULL, then ASSERT().
343 @param Value A pointer to the pointer value for the compare exchange
345 @param CompareValue Pointer value used in compare operation.
346 @param ExchangeValue Pointer value used in exchange operation.
351 InterlockedCompareExchangePointer (
353 IN VOID
*CompareValue
,
354 IN VOID
*ExchangeValue
359 SizeOfValue
= sizeof (*Value
);
361 switch (SizeOfValue
) {
362 case sizeof (UINT32
):
363 return (VOID
*)(UINTN
)InterlockedCompareExchange32 (
365 (UINT32
)(UINTN
)CompareValue
,
366 (UINT32
)(UINTN
)ExchangeValue
368 case sizeof (UINT64
):
369 return (VOID
*)(UINTN
)InterlockedCompareExchange64 (
371 (UINT64
)(UINTN
)CompareValue
,
372 (UINT64
)(UINTN
)ExchangeValue