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     lock->mutex = lck_mtx_alloc_init( lockGroup, LCK_ATTR_NULL );
 139     if( lock->mutex ) {
 140                 lock->group = lockGroup;
 141         lock->thread = 0;
 142         lock->count  = 0;
 143     } else {
 144         IODelete( lock, _IORecursiveLock, 1 );
 145         lock = 0;
 146     }
 147
 148     return( (IORecursiveLock *) lock );
 149 }
 150
 151
 152 IORecursiveLock * IORecursiveLockAlloc( void )
 153 {
 154     return IORecursiveLockAllocWithLockGroup( IOLockGroup );
 155 }
 156
 157 void IORecursiveLockFree( IORecursiveLock * _lock )
 158 {
 159     _IORecursiveLock * lock = (_IORecursiveLock *)_lock;
 160
 161     lck_mtx_free( lock->mutex, lock->group );
 162     IODelete( lock, _IORecursiveLock, 1 );
 163 }
 164
 165 lck_mtx_t * IORecursiveLockGetMachLock( IORecursiveLock * lock )
 166 {
 167     return( lock->mutex );
 168 }
 169
 170 void IORecursiveLockLock( IORecursiveLock * _lock)
 171 {
 172     _IORecursiveLock * lock = (_IORecursiveLock *)_lock;
 173
 174     if( lock->thread == IOThreadSelf())
 175         lock->count++;
 176     else {
 177         lck_mtx_lock( lock->mutex );
 178         assert( lock->thread == 0 );
 179         assert( lock->count == 0 );
 180         lock->thread = IOThreadSelf();
 181         lock->count = 1;
 182     }
 183 }
 184
 185 boolean_t IORecursiveLockTryLock( IORecursiveLock * _lock)
 186 {
 187     _IORecursiveLock * lock = (_IORecursiveLock *)_lock;
 188
 189     if( lock->thread == IOThreadSelf()) {
 190         lock->count++;
 191         return( true );
 192     } else {
 193         if( lck_mtx_try_lock( lock->mutex )) {
 194             assert( lock->thread == 0 );
 195             assert( lock->count == 0 );
 196             lock->thread = IOThreadSelf();
 197             lock->count = 1;
 198             return( true );
 199         }
 200     }
 201     return( false );
 202 }
 203
 204 void IORecursiveLockUnlock( IORecursiveLock * _lock)
 205 {
 206     _IORecursiveLock * lock = (_IORecursiveLock *)_lock;
 207
 208     assert( lock->thread == IOThreadSelf() );
 209
 210     if( 0 == (--lock->count)) {
 211         lock->thread = 0;
 212         lck_mtx_unlock( lock->mutex );
 213     }
 214 }
 215
 216 boolean_t IORecursiveLockHaveLock( const IORecursiveLock * _lock)
 217 {
 218     _IORecursiveLock * lock = (_IORecursiveLock *)_lock;
 219
 220     return( lock->thread == IOThreadSelf());
 221 }
 222
 223 int IORecursiveLockSleep(IORecursiveLock *_lock, void *event, UInt32 interType)
 224 {
 225     _IORecursiveLock * lock = (_IORecursiveLock *)_lock;
 226     UInt32 count = lock->count;
 227     int res;
 228
 229     assert(lock->thread == IOThreadSelf());
 230
 231     lock->count = 0;
 232     lock->thread = 0;
 233     res = lck_mtx_sleep(lock->mutex, LCK_SLEEP_PROMOTED_PRI, (event_t) event, (wait_interrupt_t) interType);
 234
 235     // Must re-establish the recursive lock no matter why we woke up
 236     // otherwise we would potentially leave the return path corrupted.
 237     assert(lock->thread == 0);
 238     assert(lock->count == 0);
 239     lock->thread = IOThreadSelf();
 240     lock->count = count;
 241     return res;
 242 }
 243
 244 int     IORecursiveLockSleepDeadline( IORecursiveLock * _lock, void *event,
 245                                   AbsoluteTime deadline, UInt32 interType)
 246 {
 247     _IORecursiveLock * lock = (_IORecursiveLock *)_lock;
 248     UInt32 count = lock->count;
 249     int res;
 250
 251     assert(lock->thread == IOThreadSelf());
 252
 253     lock->count = 0;
 254     lock->thread = 0;
 255     res = lck_mtx_sleep_deadline(lock->mutex, LCK_SLEEP_PROMOTED_PRI, (event_t) event,
 256                                                                       (wait_interrupt_t) interType, __OSAbsoluteTime(deadline));
 257
 258     // Must re-establish the recursive lock no matter why we woke up
 259     // otherwise we would potentially leave the return path corrupted.
 260     assert(lock->thread == 0);
 261     assert(lock->count == 0);
 262     lock->thread = IOThreadSelf();
 263     lock->count = count;
 264     return res;
 265 }
 266
 267 void IORecursiveLockWakeup(IORecursiveLock *, void *event, bool oneThread)
 268 {
 269     thread_wakeup_prim((event_t) event, oneThread, THREAD_AWAKENED);
 270 }
 271
 272 /*
 273  * Complex (read/write) lock operations
 274  */
 275
 276 IORWLock * IORWLockAlloc( void )
 277 {
 278     return(  lck_rw_alloc_init(IOLockGroup, LCK_ATTR_NULL)  );
 279 }
 280
 281 void    IORWLockFree( IORWLock * lock)
 282 {
 283     lck_rw_free( lock, IOLockGroup);
 284 }
 285
 286 lck_rw_t * IORWLockGetMachLock( IORWLock * lock)
 287 {
 288     return( (lck_rw_t *)lock);
 289 }
 290
 291
 292 /*
 293  * Spin locks
 294  */
 295
 296 IOSimpleLock * IOSimpleLockAlloc( void )
 297 {
 298     return( lck_spin_alloc_init( IOLockGroup, LCK_ATTR_NULL) );
 299 }
 300
 301 void IOSimpleLockInit( IOSimpleLock * lock)
 302 {
 303     lck_spin_init( lock, IOLockGroup, LCK_ATTR_NULL);
 304 }
 305
 306 void IOSimpleLockFree( IOSimpleLock * lock )
 307 {
 308     lck_spin_free( lock, IOLockGroup);
 309 }
 310
 311 lck_spin_t * IOSimpleLockGetMachLock( IOSimpleLock * lock)
 312 {
 313     return( (lck_spin_t *)lock);
 314 }
 315
 316 } /* extern "C" */
 317
 318