iokit/Kernel/IOBufferMemoryDescriptor.cpp

   1 /*
   2  * Copyright (c) 1998-2000 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   6  * The contents of this file constitute Original Code as defined in and
   7  * are subject to the Apple Public Source License Version 1.1 (the
   8  * "License").  You may not use this file except in compliance with the
   9  * License.  Please obtain a copy of the License at
  10  * http://www.apple.com/publicsource and read it before using this file.
  11  *
  12  * This Original Code and all software distributed under the License are
  13  * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  14  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  15  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  16  * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT.  Please see the
  17  * License for the specific language governing rights and limitations
  18  * under the License.
  19  *
  20  * @APPLE_LICENSE_HEADER_END@
  21  */
  22 #include <IOKit/assert.h>
  23 #include <IOKit/system.h>
  24
  25 #include <IOKit/IOLib.h>
  26 #include <IOKit/IOBufferMemoryDescriptor.h>
  27
  28 __BEGIN_DECLS
  29 void ipc_port_release_send(ipc_port_t port);
  30 __END_DECLS
  31
  32 extern "C" vm_map_t IOPageableMapForAddress( vm_address_t address );
  33
  34 #define super IOGeneralMemoryDescriptor
  35 OSDefineMetaClassAndStructors(IOBufferMemoryDescriptor,
  36                                 IOGeneralMemoryDescriptor);
  37
  38 bool IOBufferMemoryDescriptor::initWithAddress(
  39                                   void *      /* address       */ ,
  40                                   IOByteCount /* withLength    */ ,
  41                                   IODirection /* withDirection */ )
  42 {
  43     return false;
  44 }
  45
  46 bool IOBufferMemoryDescriptor::initWithAddress(
  47                                   vm_address_t /* address       */ ,
  48                                   IOByteCount  /* withLength    */ ,
  49                                   IODirection  /* withDirection */ ,
  50                                   task_t       /* withTask      */ )
  51 {
  52     return false;
  53 }
  54
  55 bool IOBufferMemoryDescriptor::initWithPhysicalAddress(
  56                                   IOPhysicalAddress /* address       */ ,
  57                                   IOByteCount       /* withLength    */ ,
  58                                   IODirection       /* withDirection */ )
  59 {
  60     return false;
  61 }
  62
  63 bool IOBufferMemoryDescriptor::initWithPhysicalRanges(
  64                                   IOPhysicalRange * /* ranges        */ ,
  65                                   UInt32            /* withCount     */ ,
  66                                   IODirection       /* withDirection */ ,
  67                                   bool              /* asReference   */ )
  68 {
  69     return false;
  70 }
  71
  72 bool IOBufferMemoryDescriptor::initWithRanges(
  73                                   IOVirtualRange * /* ranges        */ ,
  74                                   UInt32           /* withCount     */ ,
  75                                   IODirection      /* withDirection */ ,
  76                                   task_t           /* withTask      */ ,
  77                                   bool             /* asReference   */ )
  78 {
  79     return false;
  80 }
  81
  82 bool IOBufferMemoryDescriptor::initWithOptions(
  83                                IOOptionBits options,
  84                                vm_size_t    capacity,
  85                                vm_offset_t  alignment)
  86 {
  87     if (!capacity)
  88         return false;
  89
  90     _options      = options;
  91     _capacity     = capacity;
  92     _physAddrs    = 0;
  93     _physSegCount = 0;
  94     _buffer       = 0;
  95
  96     if ((options & kIOMemorySharingTypeMask) && (alignment < page_size))
  97         alignment = page_size;
  98
  99     _alignment = alignment;
 100     if (options & kIOMemoryPageable)
 101         /* Allocate some kernel address space. */
 102         _buffer = IOMallocPageable(capacity, alignment);
 103     /* Allocate a wired-down buffer inside kernel space. */
 104     else if (options & kIOMemoryPhysicallyContiguous)
 105         _buffer = IOMallocContiguous(capacity, alignment, 0);
 106     else if (alignment > 1)
 107         _buffer = IOMallocAligned(capacity, alignment);
 108     else
 109         _buffer = IOMalloc(capacity);
 110
 111     if (!_buffer)
 112         return false;
 113
 114     _singleRange.v.address = (vm_address_t) _buffer;
 115     _singleRange.v.length  = capacity;
 116
 117     if (!super::initWithRanges(&_singleRange.v, 1,
 118                                 (IODirection) (options & kIOMemoryDirectionMask),
 119                                 kernel_task, true))
 120         return false;
 121
 122     if (options & kIOMemoryPageable) {
 123         _flags |= kIOMemoryRequiresWire;
 124
 125         kern_return_t kr;
 126         ipc_port_t sharedMem = (ipc_port_t) _memEntry;
 127         vm_size_t size = _ranges.v[0].length;
 128
 129         // must create the entry before any pages are allocated
 130         if( 0 == sharedMem) {
 131             kr = mach_make_memory_entry( IOPageableMapForAddress( _ranges.v[0].address ),
 132                         &size, _ranges.v[0].address,
 133                         VM_PROT_READ | VM_PROT_WRITE, &sharedMem,
 134                         NULL );
 135             if( (KERN_SUCCESS == kr) && (size != _ranges.v[0].length)) {
 136                 ipc_port_release_send( sharedMem );
 137                 kr = kIOReturnVMError;
 138             }
 139             if( KERN_SUCCESS != kr)
 140                 sharedMem = 0;
 141             _memEntry = (void *) sharedMem;
 142         }
 143
 144     } else {
 145         /* Precompute virtual-to-physical page mappings. */
 146         vm_address_t inBuffer = (vm_address_t) _buffer;
 147         _physSegCount = atop(trunc_page(inBuffer + capacity - 1) -
 148                             trunc_page(inBuffer)) + 1;
 149         _physAddrs = IONew(IOPhysicalAddress, _physSegCount);
 150         if (!_physAddrs)
 151             return false;
 152
 153         inBuffer = trunc_page(inBuffer);
 154         for (unsigned i = 0; i < _physSegCount; i++) {
 155             _physAddrs[i] = pmap_extract(get_task_pmap(kernel_task), inBuffer);
 156             assert(_physAddrs[i]); /* supposed to be wired */
 157             inBuffer += page_size;
 158         }
 159     }
 160
 161     setLength(capacity);
 162
 163     return true;
 164 }
 165
 166 IOBufferMemoryDescriptor * IOBufferMemoryDescriptor::withOptions(
 167                                             IOOptionBits options,
 168                                             vm_size_t    capacity,
 169                                             vm_offset_t  alignment = 1)
 170 {
 171     IOBufferMemoryDescriptor *me = new IOBufferMemoryDescriptor;
 172
 173     if (me && !me->initWithOptions(options, capacity, alignment)) {
 174         me->release();
 175         me = 0;
 176     }
 177     return me;
 178 }
 179
 180
 181 /*
 182  * withCapacity:
 183  *
 184  * Returns a new IOBufferMemoryDescriptor with a buffer large enough to
 185  * hold capacity bytes.  The descriptor's length is initially set to the capacity.
 186  */
 187 IOBufferMemoryDescriptor *
 188 IOBufferMemoryDescriptor::withCapacity(vm_size_t   inCapacity,
 189                                        IODirection inDirection,
 190                                        bool        inContiguous)
 191 {
 192     return( IOBufferMemoryDescriptor::withOptions(
 193                inDirection | kIOMemoryUnshared
 194                 | (inContiguous ? kIOMemoryPhysicallyContiguous : 0),
 195                inCapacity, inContiguous ? inCapacity : 1 ));
 196 }
 197
 198 /*
 199  * initWithBytes:
 200  *
 201  * Initialize a new IOBufferMemoryDescriptor preloaded with bytes (copied).
 202  * The descriptor's length and capacity are set to the input buffer's size.
 203  */
 204 bool IOBufferMemoryDescriptor::initWithBytes(const void * inBytes,
 205                                              vm_size_t    inLength,
 206                                              IODirection  inDirection,
 207                                              bool         inContiguous)
 208 {
 209     if (!initWithOptions(
 210                inDirection | kIOMemoryUnshared
 211                 | (inContiguous ? kIOMemoryPhysicallyContiguous : 0),
 212                inLength, inLength ))
 213         return false;
 214
 215     // start out with no data
 216     setLength(0);
 217
 218     if (!appendBytes(inBytes, inLength))
 219         return false;
 220
 221     return true;
 222 }
 223
 224 /*
 225  * withBytes:
 226  *
 227  * Returns a new IOBufferMemoryDescriptor preloaded with bytes (copied).
 228  * The descriptor's length and capacity are set to the input buffer's size.
 229  */
 230 IOBufferMemoryDescriptor *
 231 IOBufferMemoryDescriptor::withBytes(const void * inBytes,
 232                                     vm_size_t    inLength,
 233                                     IODirection  inDirection,
 234                                     bool         inContiguous)
 235 {
 236     IOBufferMemoryDescriptor *me = new IOBufferMemoryDescriptor;
 237
 238     if (me && !me->initWithBytes(inBytes, inLength, inDirection, inContiguous)){
 239         me->release();
 240         me = 0;
 241     }
 242     return me;
 243 }
 244
 245 /*
 246  * free:
 247  *
 248  * Free resources
 249  */
 250 void IOBufferMemoryDescriptor::free()
 251 {
 252     IOOptionBits options   = _options;
 253     vm_size_t    size      = _capacity;
 254     void *       buffer    = _buffer;
 255     vm_offset_t  alignment = _alignment;
 256
 257     if (_physAddrs)
 258         IODelete(_physAddrs, IOPhysicalAddress, _physSegCount);
 259
 260     /* super::free may unwire - deallocate buffer afterwards */
 261     super::free();
 262
 263     if (buffer) {
 264         if (options & kIOMemoryPageable)
 265             IOFreePageable(buffer, size);
 266         else {
 267             if (options & kIOMemoryPhysicallyContiguous)
 268                 IOFreeContiguous(buffer, size);
 269             else if (alignment > 1)
 270                 IOFreeAligned(buffer, size);
 271             else
 272                 IOFree(buffer, size);
 273         }
 274     }
 275 }
 276
 277 /*
 278  * getCapacity:
 279  *
 280  * Get the buffer capacity
 281  */
 282 vm_size_t IOBufferMemoryDescriptor::getCapacity() const
 283 {
 284     return _capacity;
 285 }
 286
 287 /*
 288  * setLength:
 289  *
 290  * Change the buffer length of the memory descriptor.  When a new buffer
 291  * is created, the initial length of the buffer is set to be the same as
 292  * the capacity.  The length can be adjusted via setLength for a shorter
 293  * transfer (there is no need to create more buffer descriptors when you
 294  * can reuse an existing one, even for different transfer sizes).   Note
 295  * that the specified length must not exceed the capacity of the buffer.
 296  */
 297 void IOBufferMemoryDescriptor::setLength(vm_size_t length)
 298 {
 299     assert(length <= _capacity);
 300
 301     _length = length;
 302     _singleRange.v.length = length;
 303 }
 304
 305 /*
 306  * setDirection:
 307  *
 308  * Change the direction of the transfer.  This method allows one to redirect
 309  * the descriptor's transfer direction.  This eliminates the need to destroy
 310  * and create new buffers when different transfer directions are needed.
 311  */
 312 void IOBufferMemoryDescriptor::setDirection(IODirection direction)
 313 {
 314     _direction = direction;
 315 }
 316
 317 /*
 318  * appendBytes:
 319  *
 320  * Add some data to the end of the buffer.  This method automatically
 321  * maintains the memory descriptor buffer length.  Note that appendBytes
 322  * will not copy past the end of the memory descriptor's current capacity.
 323  */
 324 bool
 325 IOBufferMemoryDescriptor::appendBytes(const void * bytes, vm_size_t withLength)
 326 {
 327     vm_size_t actualBytesToCopy = min(withLength, _capacity - _length);
 328
 329     assert(_length <= _capacity);
 330     bcopy(/* from */ bytes, (void *)(_singleRange.v.address + _length),
 331           actualBytesToCopy);
 332     _length += actualBytesToCopy;
 333     _singleRange.v.length += actualBytesToCopy;
 334
 335     return true;
 336 }
 337
 338 /*
 339  * getBytesNoCopy:
 340  *
 341  * Return the virtual address of the beginning of the buffer
 342  */
 343 void * IOBufferMemoryDescriptor::getBytesNoCopy()
 344 {
 345     return (void *)_singleRange.v.address;
 346 }
 347
 348 /*
 349  * getBytesNoCopy:
 350  *
 351  * Return the virtual address of an offset from the beginning of the buffer
 352  */
 353 void *
 354 IOBufferMemoryDescriptor::getBytesNoCopy(vm_size_t start, vm_size_t withLength)
 355 {
 356     if (start < _length && (start + withLength) <= _length)
 357         return (void *)(_singleRange.v.address + start);
 358     return 0;
 359 }
 360
 361 /*
 362  * getPhysicalSegment:
 363  *
 364  * Get the physical address of the buffer, relative to the current position.
 365  * If the current position is at the end of the buffer, a zero is returned.
 366  */
 367 IOPhysicalAddress
 368 IOBufferMemoryDescriptor::getPhysicalSegment(IOByteCount offset,
 369                                         IOByteCount * lengthOfSegment)
 370 {
 371     IOPhysicalAddress physAddr;
 372
 373     if( offset != _position)
 374         setPosition( offset );
 375
 376     assert(_position <= _length);
 377
 378     /* Fail gracefully if the position is at (or past) the end-of-buffer. */
 379     if (_position >= _length) {
 380         *lengthOfSegment = 0;
 381         return 0;
 382     }
 383
 384     if (_options & kIOMemoryPageable) {
 385         physAddr = super::getPhysicalSegment(offset, lengthOfSegment);
 386
 387     } else {
 388         /* Compute the largest contiguous physical length possible. */
 389         vm_address_t actualPos  = _singleRange.v.address + _position;
 390         vm_address_t actualPage = trunc_page(actualPos);
 391         unsigned     physInd    = atop(actualPage-trunc_page(_singleRange.v.address));
 392
 393         vm_size_t physicalLength = actualPage + page_size - actualPos;
 394         for (unsigned index = physInd + 1; index < _physSegCount &&
 395             _physAddrs[index] == _physAddrs[index-1] + page_size; index++) {
 396             physicalLength += page_size;
 397         }
 398
 399         /* Clip contiguous physical length at the end-of-buffer. */
 400         if (physicalLength > _length - _position)
 401             physicalLength = _length - _position;
 402
 403         *lengthOfSegment = physicalLength;
 404         physAddr = _physAddrs[physInd] + (actualPos - actualPage);
 405     }
 406
 407     return physAddr;
 408 }
 409
 410 OSMetaClassDefineReservedUnused(IOBufferMemoryDescriptor, 0);
 411 OSMetaClassDefineReservedUnused(IOBufferMemoryDescriptor, 1);
 412 OSMetaClassDefineReservedUnused(IOBufferMemoryDescriptor, 2);
 413 OSMetaClassDefineReservedUnused(IOBufferMemoryDescriptor, 3);
 414 OSMetaClassDefineReservedUnused(IOBufferMemoryDescriptor, 4);
 415 OSMetaClassDefineReservedUnused(IOBufferMemoryDescriptor, 5);
 416 OSMetaClassDefineReservedUnused(IOBufferMemoryDescriptor, 6);
 417 OSMetaClassDefineReservedUnused(IOBufferMemoryDescriptor, 7);
 418 OSMetaClassDefineReservedUnused(IOBufferMemoryDescriptor, 8);
 419 OSMetaClassDefineReservedUnused(IOBufferMemoryDescriptor, 9);
 420 OSMetaClassDefineReservedUnused(IOBufferMemoryDescriptor, 10);
 421 OSMetaClassDefineReservedUnused(IOBufferMemoryDescriptor, 11);
 422 OSMetaClassDefineReservedUnused(IOBufferMemoryDescriptor, 12);
 423 OSMetaClassDefineReservedUnused(IOBufferMemoryDescriptor, 13);
 424 OSMetaClassDefineReservedUnused(IOBufferMemoryDescriptor, 14);
 425 OSMetaClassDefineReservedUnused(IOBufferMemoryDescriptor, 15);