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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.
16 // Include common header file for this module.
20 #include "BaseLibInternals.h"
23 // GCC inline assembly for Read Write Barrier
25 #define _ReadWriteBarrier() do { asm volatile ("": : : "memory"); } while(0)
27 #define SPIN_LOCK_RELEASED ((UINTN) 1)
28 #define SPIN_LOCK_ACQUIRED ((UINTN) 2)
31 Retrieves the architecture specific spin lock alignment requirements for
32 optimal spin lock performance.
34 This function retrieves the spin lock alignment requirements for optimal
35 performance on a given CPU architecture. The spin lock alignment must be a
36 power of two and is returned by this function. If there are no alignment
37 requirements, then 1 must be returned. The spin lock synchronization
38 functions must function correctly if the spin lock size and alignment values
39 returned by this function are not used at all. These values are hints to the
40 consumers of the spin lock synchronization functions to obtain optimal spin
43 @return The architecture specific spin lock alignment.
48 GetSpinLockProperties (
52 // @bug May use a PCD entry to determine this alignment.
57 Initializes a spin lock to the released state and returns the spin lock.
59 This function initializes the spin lock specified by SpinLock to the released
60 state, and returns SpinLock. Optimal performance can be achieved by calling
61 GetSpinLockProperties() to determine the size and alignment requirements for
64 If SpinLock is NULL, then ASSERT().
66 @param SpinLock A pointer to the spin lock to initialize to the released
75 OUT SPIN_LOCK
*SpinLock
78 ASSERT (SpinLock
!= NULL
);
81 *SpinLock
= SPIN_LOCK_RELEASED
;
88 Waits until a spin lock can be placed in the acquired state.
90 This function checks the state of the spin lock specified by SpinLock. If
91 SpinLock is in the released state, then this function places SpinLock in the
92 acquired state and returns SpinLock. Otherwise, this function waits
93 indefinitely for the spin lock to be released, and then places it in the
94 acquired state and returns SpinLock. All state transitions of SpinLock must
95 be performed using MP safe mechanisms.
97 If SpinLock is NULL, then ASSERT().
98 If SpinLock was not initialized with InitializeSpinLock(), then ASSERT().
99 If PcdSpinLockTimeout is not zero, and SpinLock is can not be acquired in
100 PcdSpinLockTimeout microseconds, then ASSERT().
102 @param SpinLock A pointer to the spin lock to place in the acquired state.
110 IN OUT SPIN_LOCK
*SpinLock
120 if (PcdGet32 (PcdSpinLockTimeout
) > 0) {
121 Tick
= GetPerformanceCounter ();
122 Timeout
= DivU64x32 (
124 GetPerformanceCounterProperties (&Start
, &End
),
125 PcdGet32 (PcdSpinLockTimeout
)
136 while (!AcquireSpinLockOrFail (SpinLock
)) {
138 ASSERT ((Start
< End
) ^ (Tick
<= GetPerformanceCounter ()));
144 Attempts to place a spin lock in the acquired state.
146 This function checks the state of the spin lock specified by SpinLock. If
147 SpinLock is in the released state, then this function places SpinLock in the
148 acquired state and returns TRUE. Otherwise, FALSE is returned. All state
149 transitions of SpinLock must be performed using MP safe mechanisms.
151 If SpinLock is NULL, then ASSERT().
152 If SpinLock was not initialized with InitializeSpinLock(), then ASSERT().
154 @param SpinLock A pointer to the spin lock to place in the acquired state.
156 @retval TRUE SpinLock was placed in the acquired state.
157 @retval FALSE SpinLock could not be acquired.
162 AcquireSpinLockOrFail (
163 IN OUT SPIN_LOCK
*SpinLock
169 ASSERT (SpinLock
!= NULL
);
171 LockValue
= *SpinLock
;
172 ASSERT (LockValue
== SPIN_LOCK_ACQUIRED
|| LockValue
== SPIN_LOCK_RELEASED
);
174 _ReadWriteBarrier ();
175 Result
= InterlockedCompareExchangePointer (
177 (VOID
*)SPIN_LOCK_RELEASED
,
178 (VOID
*)SPIN_LOCK_ACQUIRED
181 _ReadWriteBarrier ();
182 return (BOOLEAN
) (Result
== (VOID
*) SPIN_LOCK_RELEASED
);
186 Releases a spin lock.
188 This function places the spin lock specified by SpinLock in the release state
189 and returns SpinLock.
191 If SpinLock is NULL, then ASSERT().
192 If SpinLock was not initialized with InitializeSpinLock(), then ASSERT().
194 @param SpinLock A pointer to the spin lock to release.
202 IN OUT SPIN_LOCK
*SpinLock
207 ASSERT (SpinLock
!= NULL
);
209 LockValue
= *SpinLock
;
210 ASSERT (LockValue
== SPIN_LOCK_ACQUIRED
|| LockValue
== SPIN_LOCK_RELEASED
);
212 _ReadWriteBarrier ();
213 *SpinLock
= SPIN_LOCK_RELEASED
;
214 _ReadWriteBarrier ();
220 Performs an atomic increment of an 32-bit unsigned integer.
222 Performs an atomic increment of the 32-bit unsigned integer specified by
223 Value and returns the incremented value. The increment operation must be
224 performed using MP safe mechanisms. The state of the return value is not
225 guaranteed to be MP safe.
227 If Value is NULL, then ASSERT().
229 @param Value A pointer to the 32-bit value to increment.
231 @return The incremented value.
236 InterlockedIncrement (
240 ASSERT (Value
!= NULL
);
241 return InternalSyncIncrement (Value
);
245 Performs an atomic decrement of an 32-bit unsigned integer.
247 Performs an atomic decrement of the 32-bit unsigned integer specified by
248 Value and returns the decremented value. The decrement operation must be
249 performed using MP safe mechanisms. The state of the return value is not
250 guaranteed to be MP safe.
252 If Value is NULL, then ASSERT().
254 @param Value A pointer to the 32-bit value to decrement.
256 @return The decremented value.
261 InterlockedDecrement (
265 ASSERT (Value
!= NULL
);
266 return InternalSyncDecrement (Value
);
270 Performs an atomic compare exchange operation on a 32-bit unsigned integer.
272 Performs an atomic compare exchange operation on the 32-bit unsigned integer
273 specified by Value. If Value is equal to CompareValue, then Value is set to
274 ExchangeValue and CompareValue is returned. If Value is not equal to CompareValue,
275 then Value is returned. The compare exchange operation must be performed using
278 If Value is NULL, then ASSERT().
280 @param Value A pointer to the 32-bit value for the compare exchange
282 @param CompareValue 32-bit value used in compare operation.
283 @param ExchangeValue 32-bit value used in exchange operation.
285 @return The original *Value before exchange.
290 InterlockedCompareExchange32 (
291 IN OUT UINT32
*Value
,
292 IN UINT32 CompareValue
,
293 IN UINT32 ExchangeValue
296 ASSERT (Value
!= NULL
);
297 return InternalSyncCompareExchange32 (Value
, CompareValue
, ExchangeValue
);
301 Performs an atomic compare exchange operation on a 64-bit unsigned integer.
303 Performs an atomic compare exchange operation on the 64-bit unsigned integer specified
304 by Value. If Value is equal to CompareValue, then Value is set to ExchangeValue and
305 CompareValue is returned. If Value is not equal to CompareValue, then Value is returned.
306 The compare exchange operation must be performed using MP safe mechanisms.
308 If Value is NULL, then ASSERT().
310 @param Value A pointer to the 64-bit value for the compare exchange
312 @param CompareValue 64-bit value used in compare operation.
313 @param ExchangeValue 64-bit value used in exchange operation.
315 @return The original *Value before exchange.
320 InterlockedCompareExchange64 (
321 IN OUT UINT64
*Value
,
322 IN UINT64 CompareValue
,
323 IN UINT64 ExchangeValue
326 ASSERT (Value
!= NULL
);
327 return InternalSyncCompareExchange64 (Value
, CompareValue
, ExchangeValue
);
331 Performs an atomic compare exchange operation on a pointer value.
333 Performs an atomic compare exchange operation on the pointer value specified
334 by Value. If Value is equal to CompareValue, then Value is set to
335 ExchangeValue and CompareValue is returned. If Value is not equal to
336 CompareValue, then Value is returned. The compare exchange operation must be
337 performed using MP safe mechanisms.
339 If Value is NULL, then ASSERT().
341 @param Value A pointer to the pointer value for the compare exchange
343 @param CompareValue Pointer value used in compare operation.
344 @param ExchangeValue Pointer value used in exchange operation.
349 InterlockedCompareExchangePointer (
351 IN VOID
*CompareValue
,
352 IN VOID
*ExchangeValue
357 SizeOfValue
= sizeof (*Value
);
359 switch (SizeOfValue
) {
360 case sizeof (UINT32
):
361 return (VOID
*)(UINTN
)InterlockedCompareExchange32 (
363 (UINT32
)(UINTN
)CompareValue
,
364 (UINT32
)(UINTN
)ExchangeValue
366 case sizeof (UINT64
):
367 return (VOID
*)(UINTN
)InterlockedCompareExchange64 (
369 (UINT64
)(UINTN
)CompareValue
,
370 (UINT64
)(UINTN
)ExchangeValue