iokit/Kernel/IOCommandGate.cpp

   1 /*
   2  * Copyright (c) 1998-2000 Apple Computer, 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 #include <libkern/OSDebug.h>
  29
  30 #include <IOKit/IOCommandGate.h>
  31 #include <IOKit/IOWorkLoop.h>
  32 #include <IOKit/IOReturn.h>
  33 #include <IOKit/IOTimeStamp.h>
  34
  35 #define super IOEventSource
  36
  37 OSDefineMetaClassAndStructors(IOCommandGate, IOEventSource)
  38 #if __LP64__
  39 OSMetaClassDefineReservedUnused(IOCommandGate, 0);
  40 #else
  41 OSMetaClassDefineReservedUsed(IOCommandGate, 0);
  42 #endif
  43 OSMetaClassDefineReservedUnused(IOCommandGate, 1);
  44 OSMetaClassDefineReservedUnused(IOCommandGate, 2);
  45 OSMetaClassDefineReservedUnused(IOCommandGate, 3);
  46 OSMetaClassDefineReservedUnused(IOCommandGate, 4);
  47 OSMetaClassDefineReservedUnused(IOCommandGate, 5);
  48 OSMetaClassDefineReservedUnused(IOCommandGate, 6);
  49 OSMetaClassDefineReservedUnused(IOCommandGate, 7);
  50
  51 bool IOCommandGate::checkForWork() { return false; }
  52
  53 bool IOCommandGate::init(OSObject *inOwner, Action inAction)
  54 {
  55     return super::init(inOwner, (IOEventSource::Action) inAction);
  56 }
  57
  58 IOCommandGate *
  59 IOCommandGate::commandGate(OSObject *inOwner, Action inAction)
  60 {
  61     IOCommandGate *me = new IOCommandGate;
  62
  63     if (me && !me->init(inOwner, inAction)) {
  64         me->release();
  65         return 0;
  66     }
  67
  68     return me;
  69 }
  70
  71 /* virtual */ void IOCommandGate::disable()
  72 {
  73     if (workLoop && !workLoop->inGate())
  74         OSReportWithBacktrace("IOCommandGate::disable() called when not gated");
  75
  76     super::disable();
  77 }
  78
  79 /* virtual */ void IOCommandGate::enable()
  80 {
  81     if (workLoop) {
  82         closeGate();
  83         super::enable();
  84         wakeupGate(&enabled, /* oneThread */ false); // Unblock sleeping threads
  85         openGate();
  86     }
  87 }
  88
  89 /* virtual */ void IOCommandGate::free()
  90 {
  91     setWorkLoop(0);
  92     super::free();
  93 }
  94
  95 /* virtual */ void IOCommandGate::setWorkLoop(IOWorkLoop *inWorkLoop)
  96 {
  97     uintptr_t *sleepersP = (uintptr_t *) &reserved;
  98     if (!inWorkLoop && workLoop) {              // tearing down
  99         closeGate();
 100         *sleepersP |= 1;
 101         while (*sleepersP >> 1) {
 102             thread_wakeup_with_result(&enabled, THREAD_INTERRUPTED);
 103             sleepGate(sleepersP, THREAD_UNINT);
 104         }
 105         *sleepersP = 0;
 106         openGate();
 107     }
 108     else
 109
 110     super::setWorkLoop(inWorkLoop);
 111 }
 112
 113 IOReturn IOCommandGate::runCommand(void *arg0, void *arg1,
 114                                    void *arg2, void *arg3)
 115 {
 116     return runAction((Action) action, arg0, arg1, arg2, arg3);
 117 }
 118
 119 IOReturn IOCommandGate::attemptCommand(void *arg0, void *arg1,
 120                                        void *arg2, void *arg3)
 121 {
 122     return attemptAction((Action) action, arg0, arg1, arg2, arg3);
 123 }
 124
 125 IOReturn IOCommandGate::runAction(Action inAction,
 126                                   void *arg0, void *arg1,
 127                                   void *arg2, void *arg3)
 128 {
 129     if (!inAction)
 130         return kIOReturnBadArgument;
 131
 132     IOTimeStampConstant(IODBG_CMDQ(IOCMDQ_ACTION),
 133                         (uintptr_t) inAction, (uintptr_t) owner);
 134
 135     // closeGate is recursive needn't worry if we already hold the lock.
 136     closeGate();
 137
 138     // If the command gate is disabled and we aren't on the workloop thread
 139     // itself then sleep until we get enabled.
 140     IOReturn res;
 141     if (!workLoop->onThread()) {
 142         while (!enabled) {
 143             uintptr_t *sleepersP = (uintptr_t *) &reserved;
 144
 145             *sleepersP += 2;
 146             IOReturn res = sleepGate(&enabled, THREAD_ABORTSAFE);
 147             *sleepersP -= 2;
 148
 149             bool wakeupTearDown = (*sleepersP & 1);
 150             if (res || wakeupTearDown) {
 151                 openGate();
 152
 153                  if (wakeupTearDown)
 154                      commandWakeup(sleepersP);  // No further resources used
 155
 156                 return kIOReturnAborted;
 157             }
 158         }
 159     }
 160
 161     // Must be gated and on the work loop or enabled
 162     res = (*inAction)(owner, arg0, arg1, arg2, arg3);
 163     openGate();
 164
 165     return res;
 166 }
 167
 168 IOReturn IOCommandGate::attemptAction(Action inAction,
 169                                       void *arg0, void *arg1,
 170                                       void *arg2, void *arg3)
 171 {
 172     IOReturn res;
 173
 174     if (!inAction)
 175         return kIOReturnBadArgument;
 176
 177     // Try to close the gate if can't get return immediately.
 178     if (!tryCloseGate())
 179         return kIOReturnCannotLock;
 180
 181     // If the command gate is disabled then sleep until we get a wakeup
 182     if (!workLoop->onThread() && !enabled)
 183         res = kIOReturnNotPermitted;
 184     else {
 185         IOTimeStampConstant(IODBG_CMDQ(IOCMDQ_ACTION),
 186                             (uintptr_t) inAction, (uintptr_t) owner);
 187
 188         res = (*inAction)(owner, arg0, arg1, arg2, arg3);
 189     }
 190
 191     openGate();
 192
 193     return res;
 194 }
 195
 196 IOReturn IOCommandGate::commandSleep(void *event, UInt32 interruptible)
 197 {
 198     if (!workLoop->inGate())
 199         return kIOReturnNotPermitted;
 200
 201     return sleepGate(event, interruptible);
 202 }
 203
 204 IOReturn IOCommandGate::commandSleep(void *event, AbsoluteTime deadline, UInt32 interruptible)
 205 {
 206     if (!workLoop->inGate())
 207         return kIOReturnNotPermitted;
 208
 209     return sleepGate(event, deadline, interruptible);
 210 }
 211
 212 void IOCommandGate::commandWakeup(void *event, bool oneThread)
 213 {
 214     wakeupGate(event, oneThread);
 215 }