iokit/Kernel/IOLocks.cpp

   1 /*
   2  * Copyright (c) 1998-2007 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 #include <IOKit/system.h>
  30
  31 #include <IOKit/IOReturn.h>
  32 #include <IOKit/IOLib.h>
  33 #include <IOKit/assert.h>
  34
  35 #include <IOKit/IOLocksPrivate.h>
  36
  37 extern "C" {
  38 #include <kern/locks.h>
  39
  40 #if defined(__x86_64__)
  41 /* Synthetic event if none is specified, for backwards compatibility only. */
  42 static bool IOLockSleep_NO_EVENT __attribute__((used)) = 0;
  43 #endif
  44
  45 void    IOLockInitWithState( IOLock * lock, IOLockState state)
  46 {
  47     if( state == kIOLockStateLocked)
  48         lck_mtx_lock( lock);
  49 }
  50
  51 IOLock * IOLockAlloc( void )
  52 {
  53     return( lck_mtx_alloc_init(IOLockGroup, LCK_ATTR_NULL) );
  54 }
  55
  56 void    IOLockFree( IOLock * lock)
  57 {
  58     lck_mtx_free( lock, IOLockGroup);
  59 }
  60
  61 lck_mtx_t * IOLockGetMachLock( IOLock * lock)
  62 {
  63     return( (lck_mtx_t *)lock);
  64 }
  65
  66 int     IOLockSleep( IOLock * lock, void *event, UInt32 interType)
  67 {
  68     return (int) lck_mtx_sleep(lock, LCK_SLEEP_PROMOTED_PRI, (event_t) event, (wait_interrupt_t) interType);
  69 }
  70
  71 int     IOLockSleepDeadline( IOLock * lock, void *event,
  72                                 AbsoluteTime deadline, UInt32 interType)
  73 {
  74     return (int) lck_mtx_sleep_deadline(lock, LCK_SLEEP_PROMOTED_PRI, (event_t) event,
  75                                         (wait_interrupt_t) interType, __OSAbsoluteTime(deadline));
  76 }
  77
  78 void    IOLockWakeup(IOLock * lock, void *event, bool oneThread)
  79 {
  80         thread_wakeup_prim((event_t) event, oneThread, THREAD_AWAKENED);
  81 }
  82
  83 #if defined(__x86_64__)
  84 /*
  85  * For backwards compatibility, kexts built against pre-Darwin 14 headers will bind at runtime to this function,
  86  * which supports a NULL event,
  87  */
  88 int     IOLockSleep_legacy_x86_64( IOLock * lock, void *event, UInt32 interType) __asm("_IOLockSleep");
  89 int     IOLockSleepDeadline_legacy_x86_64( IOLock * lock, void *event,
  90                                            AbsoluteTime deadline, UInt32 interType) __asm("_IOLockSleepDeadline");
  91 void    IOLockWakeup_legacy_x86_64(IOLock * lock, void *event, bool oneThread) __asm("_IOLockWakeup");
  92
  93 int     IOLockSleep_legacy_x86_64( IOLock * lock, void *event, UInt32 interType)
  94 {
  95     if (event == NULL)
  96         event = (void *)&IOLockSleep_NO_EVENT;
  97
  98     return IOLockSleep(lock, event, interType);
  99 }
 100
 101 int     IOLockSleepDeadline_legacy_x86_64( IOLock * lock, void *event,
 102                              AbsoluteTime deadline, UInt32 interType)
 103 {
 104     if (event == NULL)
 105         event = (void *)&IOLockSleep_NO_EVENT;
 106
 107     return IOLockSleepDeadline(lock, event, deadline, interType);
 108 }
 109
 110 void    IOLockWakeup_legacy_x86_64(IOLock * lock, void *event, bool oneThread)
 111 {
 112     if (event == NULL)
 113         event = (void *)&IOLockSleep_NO_EVENT;
 114
 115     IOLockWakeup(lock, event, oneThread);
 116 }
 117 #endif /* defined(__x86_64__) */
 118
 119
 120 struct _IORecursiveLock {
 121         lck_mtx_t       mutex;
 122         lck_grp_t       *group;
 123         thread_t        thread;
 124         UInt32          count;
 125 };
 126
 127 IORecursiveLock * IORecursiveLockAllocWithLockGroup( lck_grp_t * lockGroup )
 128 {
 129     _IORecursiveLock * lock;
 130
 131     if( lockGroup == 0 )
 132         return( 0 );
 133
 134     lock = IONew( _IORecursiveLock, 1 );
 135     if( !lock )
 136         return( 0 );
 137
 138     lck_mtx_init( &lock->mutex, lockGroup, LCK_ATTR_NULL );
 139     lock->group = lockGroup;
 140     lock->thread = 0;
 141     lock->count  = 0;
 142
 143     return( (IORecursiveLock *) lock );
 144 }
 145
 146
 147 IORecursiveLock * IORecursiveLockAlloc( void )
 148 {
 149     return IORecursiveLockAllocWithLockGroup( IOLockGroup );
 150 }
 151
 152 void IORecursiveLockFree( IORecursiveLock * _lock )
 153 {
 154     _IORecursiveLock * lock = (_IORecursiveLock *)_lock;
 155
 156     lck_mtx_destroy(&lock->mutex, lock->group);
 157     IODelete( lock, _IORecursiveLock, 1 );
 158 }
 159
 160 lck_mtx_t * IORecursiveLockGetMachLock( IORecursiveLock * lock )
 161 {
 162     return( &lock->mutex );
 163 }
 164
 165 void IORecursiveLockLock( IORecursiveLock * _lock)
 166 {
 167     _IORecursiveLock * lock = (_IORecursiveLock *)_lock;
 168
 169     if( lock->thread == IOThreadSelf())
 170         lock->count++;
 171     else {
 172         lck_mtx_lock( &lock->mutex );
 173         assert( lock->thread == 0 );
 174         assert( lock->count == 0 );
 175         lock->thread = IOThreadSelf();
 176         lock->count = 1;
 177     }
 178 }
 179
 180 boolean_t IORecursiveLockTryLock( IORecursiveLock * _lock)
 181 {
 182     _IORecursiveLock * lock = (_IORecursiveLock *)_lock;
 183
 184     if( lock->thread == IOThreadSelf()) {
 185         lock->count++;
 186         return( true );
 187     } else {
 188         if( lck_mtx_try_lock( &lock->mutex )) {
 189             assert( lock->thread == 0 );
 190             assert( lock->count == 0 );
 191             lock->thread = IOThreadSelf();
 192             lock->count = 1;
 193             return( true );
 194         }
 195     }
 196     return( false );
 197 }
 198
 199 void IORecursiveLockUnlock( IORecursiveLock * _lock)
 200 {
 201     _IORecursiveLock * lock = (_IORecursiveLock *)_lock;
 202
 203     assert( lock->thread == IOThreadSelf() );
 204
 205     if( 0 == (--lock->count)) {
 206         lock->thread = 0;
 207         lck_mtx_unlock( &lock->mutex );
 208     }
 209 }
 210
 211 boolean_t IORecursiveLockHaveLock( const IORecursiveLock * _lock)
 212 {
 213     _IORecursiveLock * lock = (_IORecursiveLock *)_lock;
 214
 215     return( lock->thread == IOThreadSelf());
 216 }
 217
 218 int IORecursiveLockSleep(IORecursiveLock *_lock, void *event, UInt32 interType)
 219 {
 220     _IORecursiveLock * lock = (_IORecursiveLock *)_lock;
 221     UInt32 count = lock->count;
 222     int res;
 223
 224     assert(lock->thread == IOThreadSelf());
 225
 226     lock->count = 0;
 227     lock->thread = 0;
 228     res = lck_mtx_sleep(&lock->mutex, LCK_SLEEP_PROMOTED_PRI, (event_t) event, (wait_interrupt_t) interType);
 229
 230     // Must re-establish the recursive lock no matter why we woke up
 231     // otherwise we would potentially leave the return path corrupted.
 232     assert(lock->thread == 0);
 233     assert(lock->count == 0);
 234     lock->thread = IOThreadSelf();
 235     lock->count = count;
 236     return res;
 237 }
 238
 239 int     IORecursiveLockSleepDeadline( IORecursiveLock * _lock, void *event,
 240                                   AbsoluteTime deadline, UInt32 interType)
 241 {
 242     _IORecursiveLock * lock = (_IORecursiveLock *)_lock;
 243     UInt32 count = lock->count;
 244     int res;
 245
 246     assert(lock->thread == IOThreadSelf());
 247
 248     lock->count = 0;
 249     lock->thread = 0;
 250     res = lck_mtx_sleep_deadline(&lock->mutex, LCK_SLEEP_PROMOTED_PRI, (event_t) event,
 251                                                                       (wait_interrupt_t) interType, __OSAbsoluteTime(deadline));
 252
 253     // Must re-establish the recursive lock no matter why we woke up
 254     // otherwise we would potentially leave the return path corrupted.
 255     assert(lock->thread == 0);
 256     assert(lock->count == 0);
 257     lock->thread = IOThreadSelf();
 258     lock->count = count;
 259     return res;
 260 }
 261
 262 void IORecursiveLockWakeup(IORecursiveLock *, void *event, bool oneThread)
 263 {
 264     thread_wakeup_prim((event_t) event, oneThread, THREAD_AWAKENED);
 265 }
 266
 267 /*
 268  * Complex (read/write) lock operations
 269  */
 270
 271 IORWLock * IORWLockAlloc( void )
 272 {
 273     return(  lck_rw_alloc_init(IOLockGroup, LCK_ATTR_NULL)  );
 274 }
 275
 276 void    IORWLockFree( IORWLock * lock)
 277 {
 278     lck_rw_free( lock, IOLockGroup);
 279 }
 280
 281 lck_rw_t * IORWLockGetMachLock( IORWLock * lock)
 282 {
 283     return( (lck_rw_t *)lock);
 284 }
 285
 286
 287 /*
 288  * Spin locks
 289  */
 290
 291 IOSimpleLock * IOSimpleLockAlloc( void )
 292 {
 293     return( lck_spin_alloc_init( IOLockGroup, LCK_ATTR_NULL) );
 294 }
 295
 296 void IOSimpleLockInit( IOSimpleLock * lock)
 297 {
 298     lck_spin_init( lock, IOLockGroup, LCK_ATTR_NULL);
 299 }
 300
 301 void IOSimpleLockFree( IOSimpleLock * lock )
 302 {
 303     lck_spin_free( lock, IOLockGroup);
 304 }
 305
 306 lck_spin_t * IOSimpleLockGetMachLock( IOSimpleLock * lock)
 307 {
 308     return( (lck_spin_t *)lock);
 309 }
 310
 311 } /* extern "C" */
 312
 313