Add the ReadWriteBarrier in the Acquire/ReleaseSpin to block the unexpected optimizat...
[mirror_edk2.git] / 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 #include "BaseLibInternals.h"
18
19 //
20 // GCC inline assembly for Read Write Barrier
21 //
22 #define _ReadWriteBarrier() do { asm volatile ("": : : "memory"); } while(0)
23
24 #define SPIN_LOCK_RELEASED ((UINTN) 1)
25 #define SPIN_LOCK_ACQUIRED ((UINTN) 2)
26
27 /**
28 Retrieves the architecture specific spin lock alignment requirements for
29 optimal spin lock performance.
30
31 This function retrieves the spin lock alignment requirements for optimal
32 performance on a given CPU architecture. The spin lock alignment must be a
33 power of two and is returned by this function. If there are no alignment
34 requirements, then 1 must be returned. The spin lock synchronization
35 functions must function correctly if the spin lock size and alignment values
36 returned by this function are not used at all. These values are hints to the
37 consumers of the spin lock synchronization functions to obtain optimal spin
38 lock performance.
39
40 @return The architecture specific spin lock alignment.
41
42 **/
43 UINTN
44 EFIAPI
45 GetSpinLockProperties (
46 VOID
47 )
48 {
49 // @bug May use a PCD entry to determine this alignment.
50 return 32;
51 }
52
53 /**
54 Initializes a spin lock to the released state and returns the spin lock.
55
56 This function initializes the spin lock specified by SpinLock to the released
57 state, and returns SpinLock. Optimal performance can be achieved by calling
58 GetSpinLockProperties() to determine the size and alignment requirements for
59 SpinLock.
60
61 If SpinLock is NULL, then ASSERT().
62
63 @param SpinLock A pointer to the spin lock to initialize to the released
64 state.
65
66 @return SpinLock
67
68 **/
69 SPIN_LOCK *
70 EFIAPI
71 InitializeSpinLock (
72 OUT SPIN_LOCK *SpinLock
73 )
74 {
75 ASSERT (SpinLock != NULL);
76
77 _ReadWriteBarrier();
78 *SpinLock = SPIN_LOCK_RELEASED;
79 _ReadWriteBarrier();
80
81 return SpinLock;
82 }
83
84 /**
85 Waits until a spin lock can be placed in the acquired state.
86
87 This function checks the state of the spin lock specified by SpinLock. If
88 SpinLock is in the released state, then this function places SpinLock in the
89 acquired state and returns SpinLock. Otherwise, this function waits
90 indefinitely for the spin lock to be released, and then places it in the
91 acquired state and returns SpinLock. All state transitions of SpinLock must
92 be performed using MP safe mechanisms.
93
94 If SpinLock is NULL, then ASSERT().
95 If SpinLock was not initialized with InitializeSpinLock(), then ASSERT().
96 If PcdSpinLockTimeout is not zero, and SpinLock is can not be acquired in
97 PcdSpinLockTimeout microseconds, then ASSERT().
98
99 @param SpinLock A pointer to the spin lock to place in the acquired state.
100
101 @return SpinLock
102
103 **/
104 SPIN_LOCK *
105 EFIAPI
106 AcquireSpinLock (
107 IN OUT SPIN_LOCK *SpinLock
108 )
109 {
110 UINT64 Tick;
111 UINT64 Start, End;
112 UINT64 Timeout;
113
114 Tick = 0;
115 Start = 0;
116 End = 0;
117 if (PcdGet32 (PcdSpinLockTimeout) > 0) {
118 Tick = GetPerformanceCounter ();
119 Timeout = DivU64x32 (
120 MultU64x32 (
121 GetPerformanceCounterProperties (&Start, &End),
122 PcdGet32 (PcdSpinLockTimeout)
123 ),
124 1000000
125 );
126 if (Start < End) {
127 Tick += Timeout;
128 } else {
129 Tick -= Timeout;
130 }
131 }
132
133 while (!AcquireSpinLockOrFail (SpinLock)) {
134 CpuPause ();
135 ASSERT ((Start < End) ^ (Tick <= GetPerformanceCounter ()));
136 }
137 return SpinLock;
138 }
139
140 /**
141 Attempts to place a spin lock in the acquired state.
142
143 This function checks the state of the spin lock specified by SpinLock. If
144 SpinLock is in the released state, then this function places SpinLock in the
145 acquired state and returns TRUE. Otherwise, FALSE is returned. All state
146 transitions of SpinLock must be performed using MP safe mechanisms.
147
148 If SpinLock is NULL, then ASSERT().
149 If SpinLock was not initialized with InitializeSpinLock(), then ASSERT().
150
151 @param SpinLock A pointer to the spin lock to place in the acquired state.
152
153 @retval TRUE SpinLock was placed in the acquired state.
154 @retval FALSE SpinLock could not be acquired.
155
156 **/
157 BOOLEAN
158 EFIAPI
159 AcquireSpinLockOrFail (
160 IN OUT SPIN_LOCK *SpinLock
161 )
162 {
163 VOID *Result;
164
165 ASSERT (SpinLock != NULL);
166 ASSERT (*SpinLock == SPIN_LOCK_ACQUIRED || *SpinLock == SPIN_LOCK_RELEASED);
167
168 _ReadWriteBarrier ();
169 Result = InterlockedCompareExchangePointer (
170 (VOID**)SpinLock,
171 (VOID*)SPIN_LOCK_RELEASED,
172 (VOID*)SPIN_LOCK_ACQUIRED
173 );
174
175 _ReadWriteBarrier ();
176 return (BOOLEAN) (Result == (VOID*) SPIN_LOCK_RELEASED);
177 }
178
179 /**
180 Releases a spin lock.
181
182 This function places the spin lock specified by SpinLock in the release state
183 and returns SpinLock.
184
185 If SpinLock is NULL, then ASSERT().
186 If SpinLock was not initialized with InitializeSpinLock(), then ASSERT().
187
188 @param SpinLock A pointer to the spin lock to release.
189
190 @return SpinLock
191
192 **/
193 SPIN_LOCK *
194 EFIAPI
195 ReleaseSpinLock (
196 IN OUT SPIN_LOCK *SpinLock
197 )
198 {
199 ASSERT (SpinLock != NULL);
200 ASSERT (*SpinLock == SPIN_LOCK_ACQUIRED || *SpinLock == SPIN_LOCK_RELEASED);
201
202 _ReadWriteBarrier ();
203 *SpinLock = SPIN_LOCK_RELEASED;
204 _ReadWriteBarrier ();
205
206 return SpinLock;
207 }
208
209 /**
210 Performs an atomic increment of an 32-bit unsigned integer.
211
212 Performs an atomic increment of the 32-bit unsigned integer specified by
213 Value and returns the incremented value. The increment operation must be
214 performed using MP safe mechanisms. The state of the return value is not
215 guaranteed to be MP safe.
216
217 If Value is NULL, then ASSERT().
218
219 @param Value A pointer to the 32-bit value to increment.
220
221 @return The incremented value.
222
223 **/
224 UINT32
225 EFIAPI
226 InterlockedIncrement (
227 IN UINT32 *Value
228 )
229 {
230 ASSERT (Value != NULL);
231 return InternalSyncIncrement (Value);
232 }
233
234 /**
235 Performs an atomic decrement of an 32-bit unsigned integer.
236
237 Performs an atomic decrement of the 32-bit unsigned integer specified by
238 Value and returns the decremented value. The decrement operation must be
239 performed using MP safe mechanisms. The state of the return value is not
240 guaranteed to be MP safe.
241
242 If Value is NULL, then ASSERT().
243
244 @param Value A pointer to the 32-bit value to decrement.
245
246 @return The decremented value.
247
248 **/
249 UINT32
250 EFIAPI
251 InterlockedDecrement (
252 IN UINT32 *Value
253 )
254 {
255 ASSERT (Value != NULL);
256 return InternalSyncDecrement (Value);
257 }
258
259 /**
260 Performs an atomic compare exchange operation on a 32-bit unsigned integer.
261
262 Performs an atomic compare exchange operation on the 32-bit unsigned integer
263 specified by Value. If Value is equal to CompareValue, then Value is set to
264 ExchangeValue and CompareValue is returned. If Value is not equal to CompareValue,
265 then Value is returned. The compare exchange operation must be performed using
266 MP safe mechanisms.
267
268 If Value is NULL, then ASSERT().
269
270 @param Value A pointer to the 32-bit value for the compare exchange
271 operation.
272 @param CompareValue 32-bit value used in compare operation.
273 @param ExchangeValue 32-bit value used in exchange operation.
274
275 @return The original *Value before exchange.
276
277 **/
278 UINT32
279 EFIAPI
280 InterlockedCompareExchange32 (
281 IN OUT UINT32 *Value,
282 IN UINT32 CompareValue,
283 IN UINT32 ExchangeValue
284 )
285 {
286 ASSERT (Value != NULL);
287 return InternalSyncCompareExchange32 (Value, CompareValue, ExchangeValue);
288 }
289
290 /**
291 Performs an atomic compare exchange operation on a 64-bit unsigned integer.
292
293 Performs an atomic compare exchange operation on the 64-bit unsigned integer specified
294 by Value. If Value is equal to CompareValue, then Value is set to ExchangeValue and
295 CompareValue is returned. If Value is not equal to CompareValue, then Value is returned.
296 The compare exchange operation must be performed using MP safe mechanisms.
297
298 If Value is NULL, then ASSERT().
299
300 @param Value A pointer to the 64-bit value for the compare exchange
301 operation.
302 @param CompareValue 64-bit value used in compare operation.
303 @param ExchangeValue 64-bit value used in exchange operation.
304
305 @return The original *Value before exchange.
306
307 **/
308 UINT64
309 EFIAPI
310 InterlockedCompareExchange64 (
311 IN OUT UINT64 *Value,
312 IN UINT64 CompareValue,
313 IN UINT64 ExchangeValue
314 )
315 {
316 ASSERT (Value != NULL);
317 return InternalSyncCompareExchange64 (Value, CompareValue, ExchangeValue);
318 }
319
320 /**
321 Performs an atomic compare exchange operation on a pointer value.
322
323 Performs an atomic compare exchange operation on the pointer value specified
324 by Value. If Value is equal to CompareValue, then Value is set to
325 ExchangeValue and CompareValue is returned. If Value is not equal to
326 CompareValue, then Value is returned. The compare exchange operation must be
327 performed using MP safe mechanisms.
328
329 If Value is NULL, then ASSERT().
330
331 @param Value A pointer to the pointer value for the compare exchange
332 operation.
333 @param CompareValue Pointer value used in compare operation.
334 @param ExchangeValue Pointer value used in exchange operation.
335
336 **/
337 VOID *
338 EFIAPI
339 InterlockedCompareExchangePointer (
340 IN OUT VOID **Value,
341 IN VOID *CompareValue,
342 IN VOID *ExchangeValue
343 )
344 {
345 UINT8 SizeOfValue;
346
347 SizeOfValue = sizeof (*Value);
348
349 switch (SizeOfValue) {
350 case sizeof (UINT32):
351 return (VOID*)(UINTN)InterlockedCompareExchange32 (
352 (UINT32*)Value,
353 (UINT32)(UINTN)CompareValue,
354 (UINT32)(UINTN)ExchangeValue
355 );
356 case sizeof (UINT64):
357 return (VOID*)(UINTN)InterlockedCompareExchange64 (
358 (UINT64*)Value,
359 (UINT64)(UINTN)CompareValue,
360 (UINT64)(UINTN)ExchangeValue
361 );
362 default:
363 ASSERT (FALSE);
364 return NULL;
365 }
366 }