1 /*
2 * Copyright (c) 1998-2012 Apple Inc. All rights reserved.
3 *
4 * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
5 *
6 * This file contains Original Code and/or Modifications of Original Code
7 * as defined in and that are subject to the Apple Public Source License
8 * Version 2.0 (the 'License'). You may not use this file except in
9 * compliance with the License. The rights granted to you under the License
10 * may not be used to create, or enable the creation or redistribution of,
11 * unlawful or unlicensed copies of an Apple operating system, or to
12 * circumvent, violate, or enable the circumvention or violation of, any
13 * terms of an Apple operating system software license agreement.
14 *
15 * Please obtain a copy of the License at
16 * http://www.opensource.apple.com/apsl/ and read it before using this file.
17 *
18 * The Original Code and all software distributed under the License are
19 * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
20 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
21 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
22 * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
23 * Please see the License for the specific language governing rights and
24 * limitations under the License.
25 *
26 * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
27 */
28 /*
29 *
30 */
31
32 #ifndef __IOKIT_IOLOCKS_H
33 #define __IOKIT_IOLOCKS_H
34
35 #ifndef KERNEL
36 #error IOLocks.h is for kernel use only
37 #endif
38
39 #include <sys/appleapiopts.h>
40 #include <sys/cdefs.h>
41
42 #include <IOKit/system.h>
43
44 #include <IOKit/IOReturn.h>
45 #include <IOKit/IOTypes.h>
46 #include <machine/machine_routines.h>
47 #include <libkern/locks.h>
48
49 #ifdef __cplusplus
50 extern "C" {
51 #endif
52
53 /*! @var IOLockGroup
54 * Global lock group used by all IOKit locks. To simplify kext debugging and lock-heat analysis, consider using lck_* locks with a per-driver lock group, as defined in kern/locks.h.
55 */
56 extern lck_grp_t *IOLockGroup;
57
58 #if defined(XNU_KERNEL_PRIVATE)
59 #define IOLOCKS_INLINE 1
60 #endif
61
62 /*
63 * Mutex lock operations
64 */
65
66 #ifdef IOLOCKS_INLINE
67 typedef lck_mtx_t IOLock;
68 #else
69 typedef struct _IOLock IOLock;
70 #endif /* IOLOCKS_INLINE */
71
72
73 /*! @function IOLockAlloc
74 * @abstract Allocates and initializes a mutex.
75 * @discussion Allocates a mutex in general purpose memory, and initializes it. Mutexes are general purpose blocking mutual exclusion locks, supplied by libkern/locks.h. This function may block and so should not be called from interrupt level or while a spin lock is held. IOLocks use the global IOKit lock group, IOLockGroup. To simplify kext debugging and lock-heat analysis, consider using lck_* locks with a per-driver lock group, as defined in kern/locks.h.
76 * @result Pointer to the allocated lock, or zero on failure. */
77
78 IOLock * IOLockAlloc( void );
79
80 /*! @function IOLockFree
81 * @abstract Frees a mutex.
82 * @discussion Frees a lock allocated with IOLockAlloc. Mutex should be unlocked with no waiters.
83 * @param lock Pointer to the allocated lock. */
84
85 void IOLockFree( IOLock * lock);
86
87 /*! @function IOLockGetMachLock
88 * @abstract Accessor to a Mach mutex.
89 * @discussion Accessor to the Mach mutex.
90 * @param lock Pointer to the allocated lock. */
91
92 lck_mtx_t * IOLockGetMachLock( IOLock * lock);
93
94 /*! @function IOLockLock
95 * @abstract Lock a mutex.
96 * @discussion Lock the mutex. If the lock is held by any thread, block waiting for its unlock. This function may block and so should not be called from interrupt level or while a spin lock is held. Locking the mutex recursively from one thread will result in deadlock.
97 * @param lock Pointer to the allocated lock. */
98
99 #ifdef IOLOCKS_INLINE
100 #define IOLockLock(l) lck_mtx_lock(l)
101 #else
102 void IOLockLock( IOLock * lock);
103 #endif /* !IOLOCKS_INLINE */
104
105 /*! @function IOLockTryLock
106 * @abstract Attempt to lock a mutex.
107 * @discussion Lock the mutex if it is currently unlocked, and return true. If the lock is held by any thread, return false.
108 * @param lock Pointer to the allocated lock.
109 * @result True if the mutex was unlocked and is now locked by the caller, otherwise false. */
110
111 #ifdef IOLOCKS_INLINE
112 #define IOLockTryLock(l) lck_mtx_try_lock(l)
113 #else
114 boolean_t IOLockTryLock( IOLock * lock);
115 #endif /* !IOLOCKS_INLINE */
116
117 /*! @function IOLockUnlock
118 * @abstract Unlock a mutex.
119 * @discussion Unlock the mutex and wake any blocked waiters. Results are undefined if the caller has not locked the mutex. This function may block and so should not be called from interrupt level or while a spin lock is held.
120 * @param lock Pointer to the allocated lock. */
121
122 #ifdef IOLOCKS_INLINE
123 #define IOLockUnlock(l) lck_mtx_unlock(l)
124 #else
125 void IOLockUnlock( IOLock * lock);
126 #endif /* !IOLOCKS_INLINE */
127
128 /*! @function IOLockSleep
129 * @abstract Sleep with mutex unlock and relock
130 * @discussion Prepare to sleep,unlock the mutex, and re-acquire it on wakeup. Results are undefined if the caller has not locked the mutex. This function may block and so should not be called from interrupt level or while a spin lock is held.
131 * @param lock Pointer to the locked lock.
132 * @param event The event to sleep on. Must be non-NULL.
133 * @param interType How can the sleep be interrupted.
134 * @result The wait-result value indicating how the thread was awakened.*/
135 int IOLockSleep( IOLock * lock, void *event, UInt32 interType) __DARWIN14_ALIAS(IOLockSleep);
136
137 int IOLockSleepDeadline( IOLock * lock, void *event,
138 AbsoluteTime deadline, UInt32 interType) __DARWIN14_ALIAS(IOLockSleepDeadline);
139
140 void IOLockWakeup(IOLock * lock, void *event, bool oneThread) __DARWIN14_ALIAS(IOLockWakeup);
141
142 #ifdef XNU_KERNEL_PRIVATE
143 /*! @enum IOLockAssertState
144 * @abstract Used with IOLockAssert to assert the state of a lock.
145 */
146 typedef enum {
147 kIOLockAssertOwned = LCK_ASSERT_OWNED,
148 kIOLockAssertNotOwned = LCK_ASSERT_NOTOWNED
149 } IOLockAssertState;
150
151 #ifdef IOLOCKS_INLINE
152 #define IOLockAssert(l, type) LCK_MTX_ASSERT(l, type)
153
154 /*! @function IOLockInlineInit()
155 * @abstract Initializes an inline lock.
156 */
157 void IOLockInlineInit(IOLock *);
158
159 /*! @function IOLockInlineDestroy()
160 * @abstract Destroys an inline lock.
161 */
162 void IOLockInlineDestroy(IOLock *);
163
164 #else
165 /*! @function IOLockAssert
166 * @abstract Assert that lock is either held or not held by current thread.
167 * @discussion Call with either kIOLockAssertOwned or kIOLockAssertNotOwned.
168 * Panics the kernel if the lock is not owned if called with kIOLockAssertOwned,
169 * and vice-versa.
170 */
171 void IOLockAssert(IOLock * lock, IOLockAssertState type);
172 #endif /* !IOLOCKS_INLINE */
173 #endif /* !XNU_KERNEL_PRIVATE */
174
175 #ifdef __APPLE_API_OBSOLETE
176
177 /* The following API is deprecated */
178
179 typedef enum {
180 kIOLockStateUnlocked = 0,
181 kIOLockStateLocked = 1
182 } IOLockState;
183
184 void IOLockInitWithState( IOLock * lock, IOLockState state);
185 #define IOLockInit( l ) IOLockInitWithState( l, kIOLockStateUnlocked);
186
187 static __inline__ void
IOTakeLock(IOLock * lock)188 IOTakeLock( IOLock * lock)
189 {
190 IOLockLock(lock);
191 }
192 static __inline__ boolean_t
IOTryLock(IOLock * lock)193 IOTryLock( IOLock * lock)
194 {
195 return IOLockTryLock(lock);
196 }
197 static __inline__ void
IOUnlock(IOLock * lock)198 IOUnlock( IOLock * lock)
199 {
200 IOLockUnlock(lock);
201 }
202
203 #endif /* __APPLE_API_OBSOLETE */
204
205 /*
206 * Recursive lock operations
207 */
208
209 typedef struct _IORecursiveLock IORecursiveLock;
210
211 /*! @function IORecursiveLockAlloc
212 * @abstract Allocates and initializes an recursive lock.
213 * @discussion Allocates a recursive lock in general purpose memory, and initializes it. Recursive locks function identically to mutexes but allow one thread to lock more than once, with balanced unlocks. IORecursiveLocks use the global IOKit lock group, IOLockGroup. To simplify kext debugging and lock-heat analysis, consider using lck_* locks with a per-driver lock group, as defined in kern/locks.h.
214 * @result Pointer to the allocated lock, or zero on failure. */
215
216 IORecursiveLock * IORecursiveLockAlloc( void );
217
218 /*! @function IORecursiveLockFree
219 * @abstract Frees a recursive lock.
220 * @discussion Frees a lock allocated with IORecursiveLockAlloc. Lock should be unlocked with no waiters.
221 * @param lock Pointer to the allocated lock. */
222
223 void IORecursiveLockFree( IORecursiveLock * lock);
224
225 /*! @function IORecursiveLockGetMachLock
226 * @abstract Accessor to a Mach mutex.
227 * @discussion Accessor to the Mach mutex.
228 * @param lock Pointer to the allocated lock. */
229
230 lck_mtx_t * IORecursiveLockGetMachLock( IORecursiveLock * lock);
231
232 /*! @function IORecursiveLockLock
233 * @abstract Lock a recursive lock.
234 * @discussion Lock the recursive lock. If the lock is held by another thread, block waiting for its unlock. This function may block and so should not be called from interrupt level or while a spin lock is held. The lock may be taken recursively by the same thread, with a balanced number of calls to IORecursiveLockUnlock.
235 * @param lock Pointer to the allocated lock. */
236
237 void IORecursiveLockLock( IORecursiveLock * lock);
238
239 /*! @function IORecursiveLockTryLock
240 * @abstract Attempt to lock a recursive lock.
241 * @discussion Lock the lock if it is currently unlocked, or held by the calling thread, and return true. If the lock is held by another thread, return false. Successful calls to IORecursiveLockTryLock should be balanced with calls to IORecursiveLockUnlock.
242 * @param lock Pointer to the allocated lock.
243 * @result True if the lock is now locked by the caller, otherwise false. */
244
245 boolean_t IORecursiveLockTryLock( IORecursiveLock * lock);
246
247 /*! @function IORecursiveLockUnlock
248 * @abstract Unlock a recursive lock.
249 * @discussion Undo one call to IORecursiveLockLock, if the lock is now unlocked wake any blocked waiters. Results are undefined if the caller does not balance calls to IORecursiveLockLock with IORecursiveLockUnlock. This function may block and so should not be called from interrupt level or while a spin lock is held.
250 * @param lock Pointer to the allocated lock. */
251
252 void IORecursiveLockUnlock( IORecursiveLock * lock);
253
254 /*! @function IORecursiveLockHaveLock
255 * @abstract Check if a recursive lock is held by the calling thread.
256 * @discussion If the lock is held by the calling thread, return true, otherwise the lock is unlocked, or held by another thread and false is returned.
257 * @param lock Pointer to the allocated lock.
258 * @result True if the calling thread holds the lock otherwise false. */
259
260 boolean_t IORecursiveLockHaveLock( const IORecursiveLock * lock);
261
262 extern int IORecursiveLockSleep( IORecursiveLock *_lock,
263 void *event, UInt32 interType);
264 extern int IORecursiveLockSleepDeadline( IORecursiveLock * _lock, void *event,
265 AbsoluteTime deadline, UInt32 interType);
266 extern void IORecursiveLockWakeup( IORecursiveLock *_lock,
267 void *event, bool oneThread);
268
269 /*
270 * Complex (read/write) lock operations
271 */
272
273 #ifdef IOLOCKS_INLINE
274 typedef lck_rw_t IORWLock;
275 #else
276 typedef struct _IORWLock IORWLock;
277 #endif /* IOLOCKS_INLINE */
278
279 /*! @function IORWLockAlloc
280 * @abstract Allocates and initializes a read/write lock.
281 * @discussion Allocates and initializes a read/write lock in general purpose memory. Read/write locks provide for multiple readers, one exclusive writer, and are supplied by libkern/locks.h. This function may block and so should not be called from interrupt level or while a spin lock is held. IORWLocks use the global IOKit lock group, IOLockGroup. To simplify kext debugging and lock-heat analysis, consider using lck_* locks with a per-driver lock group, as defined in kern/locks.h.
282 * @result Pointer to the allocated lock, or zero on failure. */
283
284 IORWLock * IORWLockAlloc( void );
285
286 /*! @function IORWLockFree
287 * @abstract Frees a read/write lock.
288 * @discussion Frees a lock allocated with IORWLockAlloc. Lock should be unlocked with no waiters.
289 * @param lock Pointer to the allocated lock. */
290
291 void IORWLockFree( IORWLock * lock);
292
293 /*! @function IORWLockGetMachLock
294 * @abstract Accessor to a Mach read/write lock.
295 * @discussion Accessor to the Mach read/write lock.
296 * @param lock Pointer to the allocated lock. */
297
298 lck_rw_t * IORWLockGetMachLock( IORWLock * lock);
299
300 /*! @function IORWLockRead
301 * @abstract Lock a read/write lock for read.
302 * @discussion Lock the lock for read, allowing multiple readers when there are no writers. If the lock is held for write, block waiting for its unlock. This function may block and so should not be called from interrupt level or while a spin lock is held. Locking the lock recursively from one thread, for read or write, can result in deadlock.
303 * @param lock Pointer to the allocated lock. */
304
305 #ifdef IOLOCKS_INLINE
306 #define IORWLockRead(l) lck_rw_lock_shared(l)
307 #else
308 void IORWLockRead(IORWLock * lock);
309 #endif /* !IOLOCKS_INLINE */
310
311 /*! @function IORWLockTryRead
312 * @abstract Attempt to lock a read/write lock for read.
313 * @discussion Lock the lock for read, allowing multiple readers when there are no writers. If the lock is held for write, return false. Return true otherwise.
314 * @param lock Pointer to the allocated lock. */
315
316 #ifdef IOLOCKS_INLINE
317 #define IORWLockTryRead(l) lck_rw_try_lock_shared(l)
318 #else
319 void IORWLockTryRead( IORWLock * lock);
320 #endif /* !IOLOCKS_INLINE */
321
322 /*! @function IORWLockWrite
323 * @abstract Lock a read/write lock for write.
324 * @discussion Lock the lock for write, allowing one writer exlusive access. If the lock is held for read or write, block waiting for its unlock. This function may block and so should not be called from interrupt level or while a spin lock is held. Locking the lock recursively from one thread, for read or write, can result in deadlock.
325 * @param lock Pointer to the allocated lock. */
326
327 #ifdef IOLOCKS_INLINE
328 #define IORWLockWrite(l) lck_rw_lock_exclusive(l)
329 #else
330 void IORWLockWrite( IORWLock * lock);
331 #endif /* !IOLOCKS_INLINE */
332
333 /*! @function IORWLockTryWrite
334 * @abstract Attempt to lock a read/write lock for write.
335 * @discussion Lock the lock for write, allowing one writer exlusive access. If the lock is held for read or write, return false. Return true otherwise.
336 * @param lock Pointer to the allocated lock. */
337
338 #ifdef IOLOCKS_INLINE
339 #define IORWLockTryWrite(l) lck_rw_try_lock_exclusive(l)
340 #else
341 void IORWLockTryWrite( IORWLock * lock);
342 #endif /* !IOLOCKS_INLINE */
343
344 /*! @function IORWLockUnlock
345 * @abstract Unlock a read/write lock.
346 * @discussion Undo one call to IORWLockRead or IORWLockWrite. Results are undefined if the caller has not locked the lock. This function may block and so should not be called from interrupt level or while a spin lock is held.
347 * @param lock Pointer to the allocated lock. */
348
349 #ifdef IOLOCKS_INLINE
350 #define IORWLockUnlock(l) lck_rw_done(l)
351 #else
352 void IORWLockUnlock( IORWLock * lock);
353 #endif /* !IOLOCKS_INLINE */
354
355 #ifdef XNU_KERNEL_PRIVATE
356 /*! @enum IORWLockAssertState
357 * @abstract Used with IORWLockAssert to assert the state of a lock.
358 */
359 typedef enum {
360 kIORWLockAssertRead = LCK_RW_ASSERT_SHARED,
361 kIORWLockAssertWrite = LCK_RW_ASSERT_EXCLUSIVE,
362 kIORWLockAssertHeld = LCK_RW_ASSERT_HELD,
363 kIORWLockAssertNotHeld = LCK_RW_ASSERT_NOTHELD
364 } IORWLockAssertState;
365
366 #ifdef IOLOCKS_INLINE
367 #define IORWLockAssert(l, type) LCK_RW_ASSERT(l, type)
368
369 /*! @function IORWLockInlineInit()
370 * @abstract Initializes an inline lock.
371 */
372 void IORWLockInlineInit(IORWLock *);
373
374 /*! @function IORWLockInlineDestroy()
375 * @abstract Destroys an inline lock.
376 */
377 void IORWLockInlineDestroy(IORWLock *);
378
379 #else
380 /*! @function IORWLockAssert
381 * @abstract Assert that a reader-writer lock is either held or not held
382 * by the current thread.
383 * @discussion Call with a value defined by the IORWLockAssertState type.
384 * If the specified lock is not in the state specified by the type argument,
385 * then the kernel will panic.
386 */
387 void IORWLockAssert(IORWLock * lock, IORWLockAssertState type);
388 #endif /* !IOLOCKS_INLINE */
389 #endif /* !XNU_KERNEL_PRIVATE */
390
391 #ifdef __APPLE_API_OBSOLETE
392
393 /* The following API is deprecated */
394
395 static __inline__ void
IOReadLock(IORWLock * lock)396 IOReadLock( IORWLock * lock)
397 {
398 IORWLockRead(lock);
399 }
400 static __inline__ void
IOWriteLock(IORWLock * lock)401 IOWriteLock( IORWLock * lock)
402 {
403 IORWLockWrite(lock);
404 }
405 static __inline__ void
IORWUnlock(IORWLock * lock)406 IORWUnlock( IORWLock * lock)
407 {
408 IORWLockUnlock(lock);
409 }
410
411 #endif /* __APPLE_API_OBSOLETE */
412
413
414 /*
415 * Simple locks. Cannot block while holding a simple lock.
416 */
417
418 #ifdef IOLOCKS_INLINE
419 typedef lck_spin_t IOSimpleLock;
420 #else
421 typedef struct _IOSimpleLock IOSimpleLock;
422 #endif /* IOLOCKS_INLINE */
423
424 /*! @function IOSimpleLockAlloc
425 * @abstract Allocates and initializes a spin lock.
426 * @discussion Allocates and initializes a spin lock in general purpose memory. Spin locks provide non-blocking mutual exclusion for synchronization between thread context and interrupt context, or for multiprocessor synchronization, and are supplied by libkern/locks.h. This function may block and so should not be called from interrupt level or while a spin lock is held. IOSimpleLocks use the global IOKit lock group, IOLockGroup. To simplify kext debugging and lock-heat analysis, consider using lck_* locks with a per-driver lock group, as defined in kern/locks.h.
427 * @result Pointer to the allocated lock, or zero on failure. */
428
429 IOSimpleLock * IOSimpleLockAlloc( void );
430
431 /*! @function IOSimpleLockFree
432 * @abstract Frees a spin lock.
433 * @discussion Frees a lock allocated with IOSimpleLockAlloc.
434 * @param lock Pointer to the lock. */
435
436 void IOSimpleLockFree( IOSimpleLock * lock );
437
438 /*! @function IOSimpleLockGetMachLock
439 * @abstract Accessor to a Mach spin lock.
440 * @discussion Accessor to the Mach spin lock.
441 * @param lock Pointer to the allocated lock. */
442
443 lck_spin_t * IOSimpleLockGetMachLock( IOSimpleLock * lock);
444
445 /*! @function IOSimpleLockInit
446 * @abstract Initialize a spin lock.
447 * @discussion Initialize a non heap allocated spin lock to the unlocked state. Use this function when your lock is, for example, a member variable. You will need to call IOSimpleLockDestroy when you are finished with the lock to avoid lock group refcount leaks.
448 * @param lock Pointer to the lock. */
449
450 void IOSimpleLockInit( IOSimpleLock * lock );
451
452 /*! @function IOSimpleLockDestroy
453 * @abstract De-initializes (destroys) a spin lock initialized with IOSimpleLockInit
454 * @discussion Destroy / De-initialize a non heap allocated spin lock, releasing any system resources such as lock group refcounts.
455 * @param lock Pointer to the lock. */
456
457 void IOSimpleLockDestroy( IOSimpleLock * lock );
458
459 /*! @function IOSimpleLockLock
460 * @abstract Lock a spin lock.
461 * @discussion Lock the spin lock. If the lock is held, spin waiting for its unlock. Spin locks disable preemption, cannot be held across any blocking operation, and should be held for very short periods. When used to synchronize between interrupt context and thread context they should be locked with interrupts disabled - IOSimpleLockLockDisableInterrupt() will do both. Locking the lock recursively from one thread will result in deadlock.
462 * @param lock Pointer to the lock. */
463
464 #ifdef IOLOCKS_INLINE
465 #define IOSimpleLockLock(l) lck_spin_lock(l)
466 #else
467 void IOSimpleLockLock( IOSimpleLock * lock );
468 #endif /* !IOLOCKS_INLINE */
469
470
471 /*! @function IOSimpleLockTryLock
472 * @abstract Attempt to lock a spin lock.
473 * @discussion Lock the spin lock if it is currently unlocked, and return true. If the lock is held, return false. Successful calls to IOSimpleLockTryLock should be balanced with calls to IOSimpleLockUnlock.
474 * @param lock Pointer to the lock.
475 * @result True if the lock was unlocked and is now locked by the caller, otherwise false. */
476
477 #ifdef IOLOCKS_INLINE
478 #define IOSimpleLockTryLock(l) lck_spin_try_lock(l)
479 #else
480 boolean_t IOSimpleLockTryLock( IOSimpleLock * lock );
481 #endif /* !IOLOCKS_INLINE */
482
483 /*! @function IOSimpleLockUnlock
484 * @abstract Unlock a spin lock.
485 * @discussion Unlock the lock, and restore preemption. Results are undefined if the caller has not locked the lock.
486 * @param lock Pointer to the lock. */
487
488 #ifdef IOLOCKS_INLINE
489 #define IOSimpleLockUnlock(l) lck_spin_unlock(l)
490 #else
491 void IOSimpleLockUnlock( IOSimpleLock * lock );
492 #endif /* !IOLOCKS_INLINE */
493
494 #ifdef XNU_KERNEL_PRIVATE
495 /*! @enum IOSimpleLockAssertState
496 * @abstract Used with IOSimpleLockAssert to assert the state of a lock.
497 */
498 typedef enum {
499 kIOSimpleLockAssertOwned = LCK_ASSERT_OWNED,
500 kIOSimpleLockAssertNotOwned = LCK_ASSERT_NOTOWNED
501 } IOSimpleLockAssertState;
502
503 #ifdef IOLOCKS_INLINE
504 #define IOSimpleLockAssert(l, type) LCK_SPIN_ASSERT(l, type)
505 #else
506 /*! @function IOSimpleLockAssert
507 * @abstract Assert that spinlock is either held or not held by current thread.
508 * @discussion Call with either kIOSimpleLockAssertOwned or kIOSimpleLockAssertNotOwned.
509 * Panics the kernel if the lock is not owned if called with
510 * kIOSimpleLockAssertOwned and vice-versa.
511 */
512 void IOSimpleLockAssert(IOSimpleLock *lock, IOSimpleLockAssertState type);
513 #endif /* !IOLOCKS_INLINE */
514 #endif /* !XNU_KERNEL_PRIVATE */
515
516 #if __LP64__
517 typedef boolean_t IOInterruptState;
518 #else
519 typedef long int IOInterruptState;
520 #endif
521
522 /*! @function IOSimpleLockLockDisableInterrupt
523 * @abstract Lock a spin lock.
524 * @discussion Lock the spin lock. If the lock is held, spin waiting for its unlock. Simple locks disable preemption, cannot be held across any blocking operation, and should be held for very short periods. When used to synchronize between interrupt context and thread context they should be locked with interrupts disabled - IOSimpleLockLockDisableInterrupt() will do both. Locking the lock recursively from one thread will result in deadlock.
525 * @param lock Pointer to the lock. */
526
527 static __inline__
528 IOInterruptState
IOSimpleLockLockDisableInterrupt(IOSimpleLock * lock)529 IOSimpleLockLockDisableInterrupt( IOSimpleLock * lock )
530 {
531 IOInterruptState state = ml_set_interrupts_enabled( false );
532 IOSimpleLockLock( lock );
533 return state;
534 }
535
536 /*! @function IOSimpleLockUnlockEnableInterrupt
537 * @abstract Unlock a spin lock, and restore interrupt state.
538 * @discussion Unlock the lock, and restore preemption and interrupts to the state as they were when the lock was taken. Results are undefined if the caller has not locked the lock.
539 * @param lock Pointer to the lock.
540 * @param state The interrupt state returned by IOSimpleLockLockDisableInterrupt() */
541
542 static __inline__
543 void
IOSimpleLockUnlockEnableInterrupt(IOSimpleLock * lock,IOInterruptState state)544 IOSimpleLockUnlockEnableInterrupt( IOSimpleLock * lock,
545 IOInterruptState state )
546 {
547 IOSimpleLockUnlock( lock );
548 ml_set_interrupts_enabled( state );
549 }
550
551 #ifdef __cplusplus
552 } /* extern "C" */
553 #endif
554
555 #endif /* !__IOKIT_IOLOCKS_H */
556