iokit/Kernel/IOCommandGate.cpp

   1 /*
   2  * Copyright (c) 1998-2000, 2009-2010 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 #define IOKIT_ENABLE_SHARED_PTR
  30
  31 #include <libkern/OSDebug.h>
  32 #include <libkern/c++/OSSharedPtr.h>
  33
  34 #include <IOKit/IOCommandGate.h>
  35 #include <IOKit/IOWorkLoop.h>
  36 #include <IOKit/IOReturn.h>
  37 #include <IOKit/IOTimeStamp.h>
  38 #include <IOKit/IOKitDebug.h>
  39
  40 #define super IOEventSource
  41
  42 OSDefineMetaClassAndStructorsWithZone(IOCommandGate, IOEventSource, ZC_NONE)
  43 #if __LP64__
  44 OSMetaClassDefineReservedUnused(IOCommandGate, 0);
  45 #else
  46 OSMetaClassDefineReservedUsedX86(IOCommandGate, 0);
  47 #endif
  48 OSMetaClassDefineReservedUnused(IOCommandGate, 1);
  49 OSMetaClassDefineReservedUnused(IOCommandGate, 2);
  50 OSMetaClassDefineReservedUnused(IOCommandGate, 3);
  51 OSMetaClassDefineReservedUnused(IOCommandGate, 4);
  52 OSMetaClassDefineReservedUnused(IOCommandGate, 5);
  53 OSMetaClassDefineReservedUnused(IOCommandGate, 6);
  54 OSMetaClassDefineReservedUnused(IOCommandGate, 7);
  55
  56 #if IOKITSTATS
  57
  58 #define IOStatisticsInitializeCounter() \
  59 do { \
  60         IOStatistics::setCounterType(IOEventSource::reserved->counter, kIOStatisticsCommandGateCounter); \
  61 } while (0)
  62
  63 #define IOStatisticsActionCall() \
  64 do { \
  65         IOStatistics::countCommandGateActionCall(IOEventSource::reserved->counter); \
  66 } while (0)
  67
  68 #else
  69
  70 #define IOStatisticsInitializeCounter()
  71 #define IOStatisticsActionCall()
  72
  73 #endif /* IOKITSTATS */
  74
  75 bool
  76 IOCommandGate::init(OSObject *inOwner, Action inAction)
  77 {
  78         bool res = super::init(inOwner, (IOEventSource::Action) inAction);
  79         if (res) {
  80                 IOStatisticsInitializeCounter();
  81         }
  82
  83         return res;
  84 }
  85
  86 OSSharedPtr<IOCommandGate>
  87 IOCommandGate::commandGate(OSObject *inOwner, Action inAction)
  88 {
  89         OSSharedPtr<IOCommandGate> me = OSMakeShared<IOCommandGate>();
  90
  91         if (me && !me->init(inOwner, inAction)) {
  92                 return nullptr;
  93         }
  94
  95         return me;
  96 }
  97
  98 /* virtual */ void
  99 IOCommandGate::disable()
 100 {
 101         if (workLoop && !workLoop->inGate()) {
 102                 OSReportWithBacktrace("IOCommandGate::disable() called when not gated");
 103         }
 104
 105         super::disable();
 106 }
 107
 108 /* virtual */ void
 109 IOCommandGate::enable()
 110 {
 111         if (workLoop) {
 112                 closeGate();
 113                 super::enable();
 114                 wakeupGate(&enabled, /* oneThread */ false); // Unblock sleeping threads
 115                 openGate();
 116         }
 117 }
 118
 119 /* virtual */ void
 120 IOCommandGate::free()
 121 {
 122         if (workLoop) {
 123                 setWorkLoop(NULL);
 124         }
 125         super::free();
 126 }
 127
 128 enum{
 129         kSleepersRemoved     = 0x00000001,
 130         kSleepersWaitEnabled = 0x00000002,
 131         kSleepersActions     = 0x00000100,
 132         kSleepersActionsMask = 0xffffff00,
 133 };
 134
 135 /* virtual */ void
 136 IOCommandGate::setWorkLoop(IOWorkLoop *inWorkLoop)
 137 {
 138         IOWorkLoop * wl;
 139         uintptr_t  * sleepersP = (uintptr_t *) &reserved;
 140         bool         defer;
 141
 142         if (!inWorkLoop && (wl = workLoop)) {           // tearing down
 143                 wl->closeGate();
 144                 *sleepersP |= kSleepersRemoved;
 145                 while (*sleepersP & kSleepersWaitEnabled) {
 146                         thread_wakeup_with_result(&enabled, THREAD_INTERRUPTED);
 147                         sleepGate(sleepersP, THREAD_UNINT);
 148                 }
 149                 *sleepersP &= ~kSleepersWaitEnabled;
 150                 defer = (0 != (kSleepersActionsMask & *sleepersP));
 151                 if (!defer) {
 152                         super::setWorkLoop(NULL);
 153                         *sleepersP &= ~kSleepersRemoved;
 154                 }
 155                 wl->openGate();
 156                 return;
 157         }
 158
 159         super::setWorkLoop(inWorkLoop);
 160 }
 161
 162 IOReturn
 163 IOCommandGate::runCommand(void *arg0, void *arg1,
 164     void *arg2, void *arg3)
 165 {
 166         return runAction((Action) action, arg0, arg1, arg2, arg3);
 167 }
 168
 169 IOReturn
 170 IOCommandGate::attemptCommand(void *arg0, void *arg1,
 171     void *arg2, void *arg3)
 172 {
 173         return attemptAction((Action) action, arg0, arg1, arg2, arg3);
 174 }
 175
 176
 177 static IOReturn
 178 IOCommandGateActionToBlock(OSObject *owner,
 179     void *arg0, void *arg1,
 180     void *arg2, void *arg3)
 181 {
 182         return ((IOEventSource::ActionBlock) arg0)();
 183 }
 184
 185 IOReturn
 186 IOCommandGate::runActionBlock(ActionBlock _action)
 187 {
 188         return runAction(&IOCommandGateActionToBlock, _action);
 189 }
 190
 191 IOReturn
 192 IOCommandGate::runAction(Action inAction,
 193     void *arg0, void *arg1,
 194     void *arg2, void *arg3)
 195 {
 196         IOWorkLoop * wl;
 197         uintptr_t  * sleepersP;
 198
 199         if (!inAction) {
 200                 return kIOReturnBadArgument;
 201         }
 202         if (!(wl = workLoop)) {
 203                 return kIOReturnNotReady;
 204         }
 205
 206         // closeGate is recursive needn't worry if we already hold the lock.
 207         wl->closeGate();
 208         sleepersP = (uintptr_t *) &reserved;
 209
 210         // If the command gate is disabled and we aren't on the workloop thread
 211         // itself then sleep until we get enabled.
 212         IOReturn res;
 213         if (!wl->onThread()) {
 214                 while (!enabled) {
 215                         IOReturn sleepResult = kIOReturnSuccess;
 216                         if (workLoop) {
 217                                 *sleepersP |= kSleepersWaitEnabled;
 218                                 sleepResult = wl->sleepGate(&enabled, THREAD_INTERRUPTIBLE);
 219                                 *sleepersP &= ~kSleepersWaitEnabled;
 220                         }
 221                         bool wakeupTearDown = (!workLoop || (0 != (*sleepersP & kSleepersRemoved)));
 222                         if ((kIOReturnSuccess != sleepResult) || wakeupTearDown) {
 223                                 wl->openGate();
 224
 225                                 if (wakeupTearDown) {
 226                                         wl->wakeupGate(sleepersP, false); // No further resources used
 227                                 }
 228                                 return kIOReturnAborted;
 229                         }
 230                 }
 231         }
 232
 233         bool trace = (gIOKitTrace & kIOTraceCommandGates) ? true : false;
 234
 235         if (trace) {
 236                 IOTimeStampStartConstant(IODBG_CMDQ(IOCMDQ_ACTION),
 237                     VM_KERNEL_ADDRHIDE(inAction), VM_KERNEL_ADDRHIDE(owner));
 238         }
 239
 240         IOStatisticsActionCall();
 241
 242         // Must be gated and on the work loop or enabled
 243
 244         *sleepersP += kSleepersActions;
 245         res = (*inAction)(owner, arg0, arg1, arg2, arg3);
 246         *sleepersP -= kSleepersActions;
 247
 248         if (trace) {
 249                 IOTimeStampEndConstant(IODBG_CMDQ(IOCMDQ_ACTION),
 250                     VM_KERNEL_ADDRHIDE(inAction), VM_KERNEL_ADDRHIDE(owner));
 251         }
 252
 253         if (kSleepersRemoved == ((kSleepersActionsMask | kSleepersRemoved) & *sleepersP)) {
 254                 // no actions outstanding
 255                 *sleepersP &= ~kSleepersRemoved;
 256                 super::setWorkLoop(NULL);
 257         }
 258
 259         wl->openGate();
 260
 261         return res;
 262 }
 263
 264 IOReturn
 265 IOCommandGate::attemptAction(Action inAction,
 266     void *arg0, void *arg1,
 267     void *arg2, void *arg3)
 268 {
 269         IOReturn res;
 270         IOWorkLoop * wl;
 271
 272         if (!inAction) {
 273                 return kIOReturnBadArgument;
 274         }
 275         if (!(wl = workLoop)) {
 276                 return kIOReturnNotReady;
 277         }
 278
 279         // Try to close the gate if can't get return immediately.
 280         if (!wl->tryCloseGate()) {
 281                 return kIOReturnCannotLock;
 282         }
 283
 284         // If the command gate is disabled then sleep until we get a wakeup
 285         if (!wl->onThread() && !enabled) {
 286                 res = kIOReturnNotPermitted;
 287         } else {
 288                 bool trace = (gIOKitTrace & kIOTraceCommandGates) ? true : false;
 289
 290                 if (trace) {
 291                         IOTimeStampStartConstant(IODBG_CMDQ(IOCMDQ_ACTION),
 292                             VM_KERNEL_ADDRHIDE(inAction), VM_KERNEL_ADDRHIDE(owner));
 293                 }
 294
 295                 IOStatisticsActionCall();
 296
 297                 res = (*inAction)(owner, arg0, arg1, arg2, arg3);
 298
 299                 if (trace) {
 300                         IOTimeStampEndConstant(IODBG_CMDQ(IOCMDQ_ACTION),
 301                             VM_KERNEL_ADDRHIDE(inAction), VM_KERNEL_ADDRHIDE(owner));
 302                 }
 303         }
 304
 305         wl->openGate();
 306
 307         return res;
 308 }
 309
 310 IOReturn
 311 IOCommandGate::commandSleep(void *event, UInt32 interruptible)
 312 {
 313         if (!workLoop->inGate()) {
 314                 /* The equivalent of 'msleep' while not holding the mutex is invalid */
 315                 panic("invalid commandSleep while not holding the gate");
 316         }
 317
 318         return sleepGate(event, interruptible);
 319 }
 320
 321 IOReturn
 322 IOCommandGate::commandSleep(void *event, AbsoluteTime deadline, UInt32 interruptible)
 323 {
 324         if (!workLoop->inGate()) {
 325                 /* The equivalent of 'msleep' while not holding the mutex is invalid */
 326                 panic("invalid commandSleep while not holding the gate");
 327         }
 328
 329         return sleepGate(event, deadline, interruptible);
 330 }
 331
 332 void
 333 IOCommandGate::commandWakeup(void *event, bool oneThread)
 334 {
 335         wakeupGate(event, oneThread);
 336 }