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1 | /** @file\r |
2 | Implementation of synchronization functions.\r |
3 | \r |
4 | Copyright (c) 2006, Intel Corporation<BR>\r |
5 | All rights reserved. This program and the accompanying materials\r |
6 | are licensed and made available under the terms and conditions of the BSD License\r |
7 | which accompanies this distribution. The full text of the license may be found at\r |
8 | http://opensource.org/licenses/bsd-license.php\r |
9 | \r |
10 | THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,\r |
11 | WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.\r |
12 | \r |
13 | Module Name: Synchronization.c\r |
14 | \r |
15 | **/\r |
16 | \r |
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17 | #include "BaseLibInternals.h"\r |
18 | \r |
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19 | #define SPIN_LOCK_RELEASED ((UINTN) 1)\r |
20 | #define SPIN_LOCK_ACQUIRED ((UINTN) 2)\r |
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21 | \r |
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22 | /**\r |
23 | Retrieves the architecture specific spin lock alignment requirements for\r |
24 | optimal spin lock performance.\r |
25 | \r |
26 | This function retrieves the spin lock alignment requirements for optimal\r |
27 | performance on a given CPU architecture. The spin lock alignment must be a\r |
28 | power of two and is returned by this function. If there are no alignment\r |
29 | requirements, then 1 must be returned. The spin lock synchronization\r |
30 | functions must function correctly if the spin lock size and alignment values\r |
31 | returned by this function are not used at all. These values are hints to the\r |
32 | consumers of the spin lock synchronization functions to obtain optimal spin\r |
33 | lock performance.\r |
34 | \r |
35 | @return The architecture specific spin lock alignment.\r |
36 | \r |
37 | **/\r |
38 | UINTN\r |
39 | EFIAPI\r |
40 | GetSpinLockProperties (\r |
41 | VOID\r |
42 | )\r |
43 | {\r |
44 | // @bug May use a PCD entry to determine this alignment.\r |
45 | return 32;\r |
46 | }\r |
47 | \r |
48 | /**\r |
49 | Initializes a spin lock to the released state and returns the spin lock.\r |
50 | \r |
51 | This function initializes the spin lock specified by SpinLock to the released\r |
52 | state, and returns SpinLock. Optimal performance can be achieved by calling\r |
53 | GetSpinLockProperties() to determine the size and alignment requirements for\r |
54 | SpinLock.\r |
55 | \r |
56 | If SpinLock is NULL, then ASSERT().\r |
57 | \r |
58 | @param SpinLock A pointer to the spin lock to initialize to the released\r |
59 | state.\r |
60 | \r |
61 | @return SpinLock\r |
62 | \r |
63 | **/\r |
64 | SPIN_LOCK *\r |
65 | EFIAPI\r |
66 | InitializeSpinLock (\r |
67 | OUT SPIN_LOCK *SpinLock\r |
68 | )\r |
69 | {\r |
70 | ASSERT (SpinLock != NULL);\r |
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71 | *SpinLock = SPIN_LOCK_RELEASED;\r |
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72 | return SpinLock;\r |
73 | }\r |
74 | \r |
75 | /**\r |
76 | Waits until a spin lock can be placed in the acquired state.\r |
77 | \r |
78 | This function checks the state of the spin lock specified by SpinLock. If\r |
79 | SpinLock is in the released state, then this function places SpinLock in the\r |
80 | acquired state and returns SpinLock. Otherwise, this function waits\r |
81 | indefinitely for the spin lock to be released, and then places it in the\r |
82 | acquired state and returns SpinLock. All state transitions of SpinLock must\r |
83 | be performed using MP safe mechanisms.\r |
84 | \r |
85 | If SpinLock is NULL, then ASSERT().\r |
86 | If SpinLock was not initialized with InitializeSpinLock(), then ASSERT().\r |
87 | If PcdSpinLockTimeout is not zero, and SpinLock is can not be acquired in\r |
88 | PcdSpinLockTimeout microseconds, then ASSERT().\r |
89 | \r |
90 | @param SpinLock A pointer to the spin lock to place in the acquired state.\r |
91 | \r |
92 | @return SpinLock\r |
93 | \r |
94 | **/\r |
95 | SPIN_LOCK *\r |
96 | EFIAPI\r |
97 | AcquireSpinLock (\r |
98 | IN OUT SPIN_LOCK *SpinLock\r |
99 | )\r |
100 | {\r |
101 | UINT64 Tick;\r |
102 | UINT64 Start, End;\r |
103 | UINT64 Timeout;\r |
104 | \r |
105 | Tick = 0;\r |
106 | Start = 0;\r |
107 | End = 0;\r |
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108 | if (PcdGet32 (PcdSpinLockTimeout) > 0) {\r |
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109 | Tick = GetPerformanceCounter ();\r |
110 | Timeout = DivU64x32 (\r |
111 | MultU64x32 (\r |
112 | GetPerformanceCounterProperties (&Start, &End),\r |
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113 | PcdGet32 (PcdSpinLockTimeout)\r |
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114 | ),\r |
115 | 1000000\r |
116 | );\r |
117 | if (Start < End) {\r |
118 | Tick += Timeout;\r |
119 | } else {\r |
120 | Tick -= Timeout;\r |
121 | }\r |
122 | }\r |
123 | \r |
124 | while (!AcquireSpinLockOrFail (SpinLock)) {\r |
125 | CpuPause ();\r |
126 | ASSERT ((Start < End) ^ (Tick <= GetPerformanceCounter ()));\r |
127 | }\r |
128 | return SpinLock;\r |
129 | }\r |
130 | \r |
131 | /**\r |
132 | Attempts to place a spin lock in the acquired state.\r |
133 | \r |
134 | This function checks the state of the spin lock specified by SpinLock. If\r |
135 | SpinLock is in the released state, then this function places SpinLock in the\r |
136 | acquired state and returns TRUE. Otherwise, FALSE is returned. All state\r |
137 | transitions of SpinLock must be performed using MP safe mechanisms.\r |
138 | \r |
139 | If SpinLock is NULL, then ASSERT().\r |
140 | If SpinLock was not initialized with InitializeSpinLock(), then ASSERT().\r |
141 | \r |
142 | @param SpinLock A pointer to the spin lock to place in the acquired state.\r |
143 | \r |
144 | @retval TRUE SpinLock was placed in the acquired state.\r |
145 | @retval FALSE SpinLock could not be acquired.\r |
146 | \r |
147 | **/\r |
148 | BOOLEAN\r |
149 | EFIAPI\r |
150 | AcquireSpinLockOrFail (\r |
151 | IN OUT SPIN_LOCK *SpinLock\r |
152 | )\r |
153 | {\r |
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154 | SPIN_LOCK LockValue;\r |
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155 | \r |
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156 | ASSERT (SpinLock != NULL);\r |
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157 | \r |
158 | LockValue = *SpinLock;\r |
159 | ASSERT (LockValue == SPIN_LOCK_ACQUIRED || LockValue == SPIN_LOCK_RELEASED);\r |
160 | \r |
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161 | return (BOOLEAN)(\r |
162 | InterlockedCompareExchangePointer (\r |
163 | (VOID**)SpinLock,\r |
164 | (VOID*)SPIN_LOCK_RELEASED,\r |
165 | (VOID*)SPIN_LOCK_ACQUIRED\r |
166 | ) == (VOID*)SPIN_LOCK_RELEASED\r |
167 | );\r |
168 | }\r |
169 | \r |
170 | /**\r |
171 | Releases a spin lock.\r |
172 | \r |
173 | This function places the spin lock specified by SpinLock in the release state\r |
174 | and returns SpinLock.\r |
175 | \r |
176 | If SpinLock is NULL, then ASSERT().\r |
177 | If SpinLock was not initialized with InitializeSpinLock(), then ASSERT().\r |
178 | \r |
179 | @param SpinLock A pointer to the spin lock to release.\r |
180 | \r |
181 | @return SpinLock\r |
182 | \r |
183 | **/\r |
184 | SPIN_LOCK *\r |
185 | EFIAPI\r |
186 | ReleaseSpinLock (\r |
187 | IN OUT SPIN_LOCK *SpinLock\r |
188 | )\r |
189 | {\r |
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190 | SPIN_LOCK LockValue;\r |
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191 | \r |
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192 | ASSERT (SpinLock != NULL);\r |
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193 | \r |
194 | LockValue = *SpinLock;\r |
195 | ASSERT (LockValue == SPIN_LOCK_ACQUIRED || LockValue == SPIN_LOCK_RELEASED);\r |
196 | \r |
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197 | *SpinLock = SPIN_LOCK_RELEASED;\r |
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198 | return SpinLock;\r |
199 | }\r |
200 | \r |
201 | /**\r |
202 | Performs an atomic increment of an 32-bit unsigned integer.\r |
203 | \r |
204 | Performs an atomic increment of the 32-bit unsigned integer specified by\r |
205 | Value and returns the incremented value. The increment operation must be\r |
206 | performed using MP safe mechanisms. The state of the return value is not\r |
207 | guaranteed to be MP safe.\r |
208 | \r |
209 | If Value is NULL, then ASSERT().\r |
210 | \r |
211 | @param Value A pointer to the 32-bit value to increment.\r |
212 | \r |
213 | @return The incremented value.\r |
214 | \r |
215 | **/\r |
216 | UINT32\r |
217 | EFIAPI\r |
218 | InterlockedIncrement (\r |
219 | IN UINT32 *Value\r |
220 | )\r |
221 | {\r |
222 | ASSERT (Value != NULL);\r |
223 | return InternalSyncIncrement (Value);\r |
224 | }\r |
225 | \r |
226 | /**\r |
227 | Performs an atomic decrement of an 32-bit unsigned integer.\r |
228 | \r |
229 | Performs an atomic decrement of the 32-bit unsigned integer specified by\r |
230 | Value and returns the decremented value. The decrement operation must be\r |
231 | performed using MP safe mechanisms. The state of the return value is not\r |
232 | guaranteed to be MP safe.\r |
233 | \r |
234 | If Value is NULL, then ASSERT().\r |
235 | \r |
236 | @param Value A pointer to the 32-bit value to decrement.\r |
237 | \r |
238 | @return The decremented value.\r |
239 | \r |
240 | **/\r |
241 | UINT32\r |
242 | EFIAPI\r |
243 | InterlockedDecrement (\r |
244 | IN UINT32 *Value\r |
245 | )\r |
246 | {\r |
247 | ASSERT (Value != NULL);\r |
248 | return InternalSyncDecrement (Value);\r |
249 | }\r |
250 | \r |
251 | /**\r |
252 | Performs an atomic compare exchange operation on a 32-bit unsigned integer.\r |
253 | \r |
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254 | Performs an atomic compare exchange operation on the 32-bit unsigned integer\r |
255 | specified by Value. If Value is equal to CompareValue, then Value is set to \r |
256 | ExchangeValue and CompareValue is returned. If Value is not equal to CompareValue,\r |
257 | then Value is returned. The compare exchange operation must be performed using \r |
258 | MP safe mechanisms.\r |
259 | \r |
260 | If Value is NULL, then ASSERT().\r |
261 | \r |
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262 | @param Value A pointer to the 32-bit value for the compare exchange\r |
263 | operation.\r |
264 | @param CompareValue 32-bit value used in compare operation.\r |
265 | @param ExchangeValue 32-bit value used in exchange operation.\r |
266 | \r |
267 | @return The original *Value before exchange.\r |
268 | \r |
269 | **/\r |
270 | UINT32\r |
271 | EFIAPI\r |
272 | InterlockedCompareExchange32 (\r |
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273 | IN OUT UINT32 *Value,\r |
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274 | IN UINT32 CompareValue,\r |
275 | IN UINT32 ExchangeValue\r |
276 | )\r |
277 | {\r |
278 | ASSERT (Value != NULL);\r |
279 | return InternalSyncCompareExchange32 (Value, CompareValue, ExchangeValue);\r |
280 | }\r |
281 | \r |
282 | /**\r |
283 | Performs an atomic compare exchange operation on a 64-bit unsigned integer.\r |
284 | \r |
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285 | Performs an atomic compare exchange operation on the 64-bit unsigned integer specified \r |
286 | by Value. If Value is equal to CompareValue, then Value is set to ExchangeValue and \r |
287 | CompareValue is returned. If Value is not equal to CompareValue, then Value is returned. \r |
288 | The compare exchange operation must be performed using MP safe mechanisms.\r |
289 | \r |
290 | If Value is NULL, then ASSERT().\r |
291 | \r |
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292 | @param Value A pointer to the 64-bit value for the compare exchange\r |
293 | operation.\r |
294 | @param CompareValue 64-bit value used in compare operation.\r |
295 | @param ExchangeValue 64-bit value used in exchange operation.\r |
296 | \r |
297 | @return The original *Value before exchange.\r |
298 | \r |
299 | **/\r |
300 | UINT64\r |
301 | EFIAPI\r |
302 | InterlockedCompareExchange64 (\r |
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303 | IN OUT UINT64 *Value,\r |
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304 | IN UINT64 CompareValue,\r |
305 | IN UINT64 ExchangeValue\r |
306 | )\r |
307 | {\r |
308 | ASSERT (Value != NULL);\r |
309 | return InternalSyncCompareExchange64 (Value, CompareValue, ExchangeValue);\r |
310 | }\r |
311 | \r |
312 | /**\r |
313 | Performs an atomic compare exchange operation on a pointer value.\r |
314 | \r |
315 | Performs an atomic compare exchange operation on the pointer value specified\r |
316 | by Value. If Value is equal to CompareValue, then Value is set to\r |
317 | ExchangeValue and CompareValue is returned. If Value is not equal to\r |
318 | CompareValue, then Value is returned. The compare exchange operation must be\r |
319 | performed using MP safe mechanisms.\r |
320 | \r |
321 | If Value is NULL, then ASSERT().\r |
322 | \r |
323 | @param Value A pointer to the pointer value for the compare exchange\r |
324 | operation.\r |
325 | @param CompareValue Pointer value used in compare operation.\r |
326 | @param ExchangeValue Pointer value used in exchange operation.\r |
327 | \r |
328 | **/\r |
329 | VOID *\r |
330 | EFIAPI\r |
331 | InterlockedCompareExchangePointer (\r |
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332 | IN OUT VOID **Value,\r |
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333 | IN VOID *CompareValue,\r |
334 | IN VOID *ExchangeValue\r |
335 | )\r |
336 | {\r |
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337 | UINT8 SizeOfValue;\r |
338 | \r |
339 | SizeOfValue = sizeof (*Value);\r |
340 | \r |
341 | switch (SizeOfValue) {\r |
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342 | case sizeof (UINT32):\r |
343 | return (VOID*)(UINTN)InterlockedCompareExchange32 (\r |
344 | (UINT32*)Value,\r |
345 | (UINT32)(UINTN)CompareValue,\r |
346 | (UINT32)(UINTN)ExchangeValue\r |
347 | );\r |
348 | case sizeof (UINT64):\r |
349 | return (VOID*)(UINTN)InterlockedCompareExchange64 (\r |
350 | (UINT64*)Value,\r |
351 | (UINT64)(UINTN)CompareValue,\r |
352 | (UINT64)(UINTN)ExchangeValue\r |
353 | );\r |
354 | default:\r |
355 | ASSERT (FALSE);\r |
356 | return NULL;\r |
357 | }\r |
358 | }\r |