1 /* 2 * Copyright (c) 1998-2009 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 41 #include <IOKit/system.h> 42 43 #include <IOKit/IOReturn.h> 44 #include <IOKit/IOTypes.h> 45 46 #ifdef __cplusplus 47 extern "C" { 48 #endif 49 50 #include <libkern/locks.h> 51 #include <machine/machine_routines.h> 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. Any blocked waiters will not be woken. 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 #if defined(__i386__) 126 void IOLockUnlock( IOLock * lock) __DARWIN10_ALIAS(IOLockUnlock); 127 #else /* !__i386__ */ 128 void IOLockUnlock( IOLock * lock); 129 #endif /* __i386__ */ 130 #endif /* !IOLOCKS_INLINE */ 131 132 /*! @function IOLockSleep 133 @abstract Sleep with mutex unlock and relock 134 @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. 135 @param lock Pointer to the locked lock. 136 @param event The event to sleep on. 137 @param interType How can the sleep be interrupted. 138 @result The wait-result value indicating how the thread was awakened.*/ 139 int IOLockSleep( IOLock * lock, void *event, UInt32 interType); 140 141 int IOLockSleepDeadline( IOLock * lock, void *event, 142 AbsoluteTime deadline, UInt32 interType); 143 144 void IOLockWakeup(IOLock * lock, void *event, bool oneThread); 145 146 #ifdef __APPLE_API_OBSOLETE 147 148 /* The following API is deprecated */ 149 150 typedef enum { 151 kIOLockStateUnlocked = 0, 152 kIOLockStateLocked = 1 153 } IOLockState; 154 155 void IOLockInitWithState( IOLock * lock, IOLockState state); 156 #define IOLockInit( l ) IOLockInitWithState( l, kIOLockStateUnlocked); 157 158 static __inline__ void IOTakeLock( IOLock * lock) { IOLockLock(lock); } 159 static __inline__ boolean_t IOTryLock( IOLock * lock) { return(IOLockTryLock(lock)); } 160 static __inline__ void IOUnlock( IOLock * lock) { IOLockUnlock(lock); } 161 162 #endif /* __APPLE_API_OBSOLETE */ 163 164 /* 165 * Recursive lock operations 166 */ 167 168 typedef struct _IORecursiveLock IORecursiveLock; 169 170 /*! @function IORecursiveLockAlloc 171 @abstract Allocates and initializes an recursive lock. 172 @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. 173 @result Pointer to the allocated lock, or zero on failure. */ 174 175 IORecursiveLock * IORecursiveLockAlloc( void ); 176 177 /*! @function IORecursiveLockFree 178 @abstract Frees a recursive lock. 179 @discussion Frees a lock allocated with IORecursiveLockAlloc. Any blocked waiters will not be woken. 180 @param lock Pointer to the allocated lock. */ 181 182 void IORecursiveLockFree( IORecursiveLock * lock); 183 184 /*! @function IORecursiveLockGetMachLock 185 @abstract Accessor to a Mach mutex. 186 @discussion Accessor to the Mach mutex. 187 @param lock Pointer to the allocated lock. */ 188 189 lck_mtx_t * IORecursiveLockGetMachLock( IORecursiveLock * lock); 190 191 /*! @function IORecursiveLockLock 192 @abstract Lock a recursive lock. 193 @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. 194 @param lock Pointer to the allocated lock. */ 195 196 void IORecursiveLockLock( IORecursiveLock * lock); 197 198 /*! @function IORecursiveLockTryLock 199 @abstract Attempt to lock a recursive lock. 200 @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. 201 @param lock Pointer to the allocated lock. 202 @result True if the lock is now locked by the caller, otherwise false. */ 203 204 boolean_t IORecursiveLockTryLock( IORecursiveLock * lock); 205 206 /*! @function IORecursiveLockUnlock 207 @abstract Unlock a recursive lock. 208 @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. 209 @param lock Pointer to the allocated lock. */ 210 211 void IORecursiveLockUnlock( IORecursiveLock * lock); 212 213 /*! @function IORecursiveLockHaveLock 214 @abstract Check if a recursive lock is held by the calling thread. 215 @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. 216 @param lock Pointer to the allocated lock. 217 @result True if the calling thread holds the lock otherwise false. */ 218 219 boolean_t IORecursiveLockHaveLock( const IORecursiveLock * lock); 220 221 extern int IORecursiveLockSleep( IORecursiveLock *_lock, 222 void *event, UInt32 interType); 223 extern int IORecursiveLockSleepDeadline( IORecursiveLock * _lock, void *event, 224 AbsoluteTime deadline, UInt32 interType); 225 extern void IORecursiveLockWakeup( IORecursiveLock *_lock, 226 void *event, bool oneThread); 227 228 /* 229 * Complex (read/write) lock operations 230 */ 231 232 #ifdef IOLOCKS_INLINE 233 typedef lck_rw_t IORWLock; 234 #else 235 typedef struct _IORWLock IORWLock; 236 #endif /* IOLOCKS_INLINE */ 237 238 /*! @function IORWLockAlloc 239 @abstract Allocates and initializes a read/write lock. 240 @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. 241 @result Pointer to the allocated lock, or zero on failure. */ 242 243 IORWLock * IORWLockAlloc( void ); 244 245 /*! @function IORWLockFree 246 @abstract Frees a read/write lock. 247 @discussion Frees a lock allocated with IORWLockAlloc. Any blocked waiters will not be woken. 248 @param lock Pointer to the allocated lock. */ 249 250 void IORWLockFree( IORWLock * lock); 251 252 /*! @function IORWLockGetMachLock 253 @abstract Accessor to a Mach read/write lock. 254 @discussion Accessor to the Mach read/write lock. 255 @param lock Pointer to the allocated lock. */ 256 257 lck_rw_t * IORWLockGetMachLock( IORWLock * lock); 258 259 /*! @function IORWLockRead 260 @abstract Lock a read/write lock for read. 261 @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. 262 @param lock Pointer to the allocated lock. */ 263 264 #ifdef IOLOCKS_INLINE 265 #define IORWLockRead(l) lck_rw_lock_shared(l) 266 #else 267 void IORWLockRead(IORWLock * lock); 268 #endif /* !IOLOCKS_INLINE */ 269 270 /*! @function IORWLockWrite 271 @abstract Lock a read/write lock for write. 272 @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. 273 @param lock Pointer to the allocated lock. */ 274 275 #ifdef IOLOCKS_INLINE 276 #define IORWLockWrite(l) lck_rw_lock_exclusive(l) 277 #else 278 void IORWLockWrite( IORWLock * lock); 279 #endif /* !IOLOCKS_INLINE */ 280 281 /*! @function IORWLockUnlock 282 @abstract Unlock a read/write lock. 283 @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. 284 @param lock Pointer to the allocated lock. */ 285 286 #ifdef IOLOCKS_INLINE 287 #define IORWLockUnlock(l) lck_rw_done(l) 288 #else 289 void IORWLockUnlock( IORWLock * lock); 290 #endif /* !IOLOCKS_INLINE */ 291 292 293 #ifdef __APPLE_API_OBSOLETE 294 295 /* The following API is deprecated */ 296 297 static __inline__ void IOReadLock( IORWLock * lock) { IORWLockRead(lock); } 298 static __inline__ void IOWriteLock( IORWLock * lock) { IORWLockWrite(lock); } 299 static __inline__ void IORWUnlock( IORWLock * lock) { IORWLockUnlock(lock); } 300 301 #endif /* __APPLE_API_OBSOLETE */ 302 303 304 /* 305 * Simple locks. Cannot block while holding a simple lock. 306 */ 307 308 #ifdef IOLOCKS_INLINE 309 typedef lck_spin_t IOSimpleLock; 310 #else 311 typedef struct _IOSimpleLock IOSimpleLock; 312 #endif /* IOLOCKS_INLINE */ 313 314 /*! @function IOSimpleLockAlloc 315 @abstract Allocates and initializes a spin lock. 316 @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. 317 @result Pointer to the allocated lock, or zero on failure. */ 318 319 IOSimpleLock * IOSimpleLockAlloc( void ); 320 321 /*! @function IOSimpleLockFree 322 @abstract Frees a spin lock. 323 @discussion Frees a lock allocated with IOSimpleLockAlloc. 324 @param lock Pointer to the lock. */ 325 326 void IOSimpleLockFree( IOSimpleLock * lock ); 327 328 /*! @function IOSimpleLockGetMachLock 329 @abstract Accessor to a Mach spin lock. 330 @discussion Accessor to the Mach spin lock. 331 @param lock Pointer to the allocated lock. */ 332 333 lck_spin_t * IOSimpleLockGetMachLock( IOSimpleLock * lock); 334 335 /*! @function IOSimpleLockInit 336 @abstract Initialize a spin lock. 337 @discussion Initialize an embedded spin lock, to the unlocked state. 338 @param lock Pointer to the lock. */ 339 340 void IOSimpleLockInit( IOSimpleLock * lock ); 341 342 /*! @function IOSimpleLockLock 343 @abstract Lock a spin lock. 344 @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. 345 @param lock Pointer to the lock. */ 346 347 #ifdef IOLOCKS_INLINE 348 #define IOSimpleLockLock(l) lck_spin_lock(l) 349 #else 350 void IOSimpleLockLock( IOSimpleLock * lock ); 351 #endif /* !IOLOCKS_INLINE */ 352 353 354 /*! @function IOSimpleLockTryLock 355 @abstract Attempt to lock a spin lock. 356 @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. 357 @param lock Pointer to the lock. 358 @result True if the lock was unlocked and is now locked by the caller, otherwise false. */ 359 360 #ifdef IOLOCKS_INLINE 361 #define IOSimpleLockTryLock(l) lck_spin_try_lock(l) 362 #else 363 boolean_t IOSimpleLockTryLock( IOSimpleLock * lock ); 364 #endif /* !IOLOCKS_INLINE */ 365 366 /*! @function IOSimpleLockUnlock 367 @abstract Unlock a spin lock. 368 @discussion Unlock the lock, and restore preemption. Results are undefined if the caller has not locked the lock. 369 @param lock Pointer to the lock. */ 370 371 #ifdef IOLOCKS_INLINE 372 #define IOSimpleLockUnlock(l) lck_spin_unlock(l) 373 #else 374 void IOSimpleLockUnlock( IOSimpleLock * lock ); 375 #endif /* !IOLOCKS_INLINE */ 376 377 #if __LP64__ 378 typedef boolean_t IOInterruptState; 379 #else 380 typedef long int IOInterruptState; 381 #endif 382 383 /*! @function IOSimpleLockLockDisableInterrupt 384 @abstract Lock a spin lock. 385 @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. 386 @param lock Pointer to the lock. */ 387 388 static __inline__ 389 IOInterruptState IOSimpleLockLockDisableInterrupt( IOSimpleLock * lock ) 390 { 391 IOInterruptState state = ml_set_interrupts_enabled( false ); 392 IOSimpleLockLock( lock ); 393 return( state ); 394 } 395 396 /*! @function IOSimpleLockUnlockEnableInterrupt 397 @abstract Unlock a spin lock, and restore interrupt state. 398 @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. 399 @param lock Pointer to the lock. 400 @param state The interrupt state returned by IOSimpleLockLockDisableInterrupt() */ 401 402 static __inline__ 403 void IOSimpleLockUnlockEnableInterrupt( IOSimpleLock * lock, 404 IOInterruptState state ) 405 { 406 IOSimpleLockUnlock( lock ); 407 ml_set_interrupts_enabled( state ); 408 } 409 410 #ifdef __cplusplus 411 } /* extern "C" */ 412 #endif 413 414 #endif /* !__IOKIT_IOLOCKS_H */ 415 416