iokit/IOKit/IOMemoryDescriptor.h

   1 /*
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   4  * @APPLE_LICENSE_HEADER_START@
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   8  * This file contains Original Code and/or Modifications of Original Code
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  10  * Version 2.0 (the 'License'). You may not use this file except in
  11  * compliance with the License. Please obtain a copy of the License at
  12  * http://www.opensource.apple.com/apsl/ and read it before using this
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  25 #ifndef _IOMEMORYDESCRIPTOR_H
  26 #define _IOMEMORYDESCRIPTOR_H
  27
  28 #include <sys/cdefs.h>
  29
  30 #include <IOKit/IOTypes.h>
  31 #include <libkern/c++/OSContainers.h>
  32
  33 __BEGIN_DECLS
  34 #include <mach/memory_object_types.h>
  35 __END_DECLS
  36
  37 struct IOPhysicalRange
  38 {
  39     IOPhysicalAddress   address;
  40     IOByteCount         length;
  41 };
  42
  43 class IOMemoryMap;
  44 class IOMapper;
  45
  46 /*
  47  * Direction of transfer, with respect to the described memory.
  48  */
  49 enum IODirection
  50 {
  51     kIODirectionNone  = 0x0,    //                    same as VM_PROT_NONE
  52     kIODirectionIn    = 0x1,    // User land 'read',  same as VM_PROT_READ
  53     kIODirectionOut   = 0x2,    // User land 'write', same as VM_PROT_WRITE
  54     kIODirectionOutIn = kIODirectionOut | kIODirectionIn,
  55     kIODirectionInOut = kIODirectionIn  | kIODirectionOut
  56 };
  57
  58 /*
  59  * IOOptionBits used in the second withRanges variant
  60  */
  61 enum {
  62     kIOMemoryDirectionMask      = 0x00000007,
  63     kIOMemoryAutoPrepare        = 0x00000008,   // Shared with Buffer MD
  64
  65     kIOMemoryTypeVirtual        = 0x00000010,
  66     kIOMemoryTypePhysical       = 0x00000020,
  67     kIOMemoryTypeUPL            = 0x00000030,
  68     kIOMemoryTypeMask           = 0x000000f0,
  69
  70     kIOMemoryAsReference        = 0x00000100,
  71     kIOMemoryBufferPageable     = 0x00000400,
  72     kIOMemoryDontMap            = 0x00000800,
  73 };
  74
  75 #define kIOMapperNone   ((IOMapper *) -1)
  76 #define kIOMapperSystem ((IOMapper *) 0)
  77
  78 /*! @class IOMemoryDescriptor : public OSObject
  79     @abstract An abstract base class defining common methods for describing physical or virtual memory.
  80     @discussion The IOMemoryDescriptor object represents a buffer or range of memory, specified as one or more physical or virtual address ranges. It contains methods to return the memory's physically contiguous segments (fragments), for use with the IOMemoryCursor, and methods to map the memory into any address space with caching and placed mapping options. */
  81
  82 class IOMemoryDescriptor : public OSObject
  83 {
  84     friend class _IOMemoryMap;
  85     friend class IOSubMemoryDescriptor;
  86
  87     OSDeclareDefaultStructors(IOMemoryDescriptor);
  88
  89 protected:
  90 /*! @struct ExpansionData
  91     @discussion This structure will be used to expand the capablilties of this class in the future.
  92     */
  93     struct ExpansionData {
  94         void *                          devicePager;
  95         unsigned int                    pagerContig:1;
  96         unsigned int                    unused:31;
  97         IOMemoryDescriptor *            memory;
  98     };
  99
 100 /*! @var reserved
 101     Reserved for future use.  (Internal use only)  */
 102     ExpansionData * reserved;
 103
 104 protected:
 105     OSSet *             _mappings;
 106     IOOptionBits        _flags;
 107     void *              _memEntry;
 108
 109     IODirection         _direction;        /* DEPRECATED: use _flags instead. direction of transfer */
 110     IOByteCount         _length;           /* length of all ranges */
 111     IOOptionBits        _tag;
 112
 113 public:
 114
 115     virtual IOPhysicalAddress getSourceSegment( IOByteCount offset,
 116                                                 IOByteCount * length );
 117     OSMetaClassDeclareReservedUsed(IOMemoryDescriptor, 0);
 118
 119 /*! @function initWithOptions
 120     @abstract Master initialiser for all variants of memory descriptors.  For a more complete description see IOMemoryDescriptor::withOptions.
 121     @discussion Note this function can be used to re-init a previously created memory descriptor.
 122     @result true on success, false on failure. */
 123     virtual bool initWithOptions(void *         buffers,
 124                                  UInt32         count,
 125                                  UInt32         offset,
 126                                  task_t         task,
 127                                  IOOptionBits   options,
 128                                  IOMapper *     mapper = 0);
 129     OSMetaClassDeclareReservedUsed(IOMemoryDescriptor, 1);
 130
 131     virtual addr64_t IOMemoryDescriptor::getPhysicalSegment64( IOByteCount offset,
 132                                                                 IOByteCount * length );
 133     OSMetaClassDeclareReservedUsed(IOMemoryDescriptor, 2);
 134
 135 private:
 136
 137     OSMetaClassDeclareReservedUnused(IOMemoryDescriptor, 3);
 138     OSMetaClassDeclareReservedUnused(IOMemoryDescriptor, 4);
 139     OSMetaClassDeclareReservedUnused(IOMemoryDescriptor, 5);
 140     OSMetaClassDeclareReservedUnused(IOMemoryDescriptor, 6);
 141     OSMetaClassDeclareReservedUnused(IOMemoryDescriptor, 7);
 142     OSMetaClassDeclareReservedUnused(IOMemoryDescriptor, 8);
 143     OSMetaClassDeclareReservedUnused(IOMemoryDescriptor, 9);
 144     OSMetaClassDeclareReservedUnused(IOMemoryDescriptor, 10);
 145     OSMetaClassDeclareReservedUnused(IOMemoryDescriptor, 11);
 146     OSMetaClassDeclareReservedUnused(IOMemoryDescriptor, 12);
 147     OSMetaClassDeclareReservedUnused(IOMemoryDescriptor, 13);
 148     OSMetaClassDeclareReservedUnused(IOMemoryDescriptor, 14);
 149     OSMetaClassDeclareReservedUnused(IOMemoryDescriptor, 15);
 150
 151 protected:
 152     virtual void free();
 153 public:
 154     static void initialize( void );
 155
 156 public:
 157 /*! @function withAddress
 158     @abstract Create an IOMemoryDescriptor to describe one virtual range of the kernel task.
 159     @discussion This method creates and initializes an IOMemoryDescriptor for memory consisting of a single virtual memory range mapped into the kernel map.
 160     @param address The virtual address of the first byte in the memory.
 161     @param withLength The length of memory.
 162     @param withDirection An I/O direction to be associated with the descriptor, which may affect the operation of the prepare and complete methods on some architectures.
 163     @result The created IOMemoryDescriptor on success, to be released by the caller, or zero on failure. */
 164
 165     static IOMemoryDescriptor * withAddress(void *       address,
 166                                             IOByteCount  withLength,
 167                                             IODirection  withDirection);
 168
 169 /*! @function withAddress
 170     @abstract Create an IOMemoryDescriptor to describe one virtual range of the specified map.
 171     @discussion This method creates and initializes an IOMemoryDescriptor for memory consisting of a single virtual memory range mapped into the specified map.
 172     @param address The virtual address of the first byte in the memory.
 173     @param withLength The length of memory.
 174     @param withDirection An I/O direction to be associated with the descriptor, which may affect the operation of the prepare and complete methods on some architectures.
 175     @param withTask The task the virtual ranges are mapped into.
 176     @result The created IOMemoryDescriptor on success, to be released by the caller, or zero on failure. */
 177
 178     static IOMemoryDescriptor * withAddress(vm_address_t address,
 179                                             IOByteCount  withLength,
 180                                             IODirection  withDirection,
 181                                             task_t       withTask);
 182
 183 /*! @function withPhysicalAddress
 184     @abstract Create an IOMemoryDescriptor to describe one physical range.
 185     @discussion This method creates and initializes an IOMemoryDescriptor for memory consisting of a single physical memory range.
 186     @param address The physical address of the first byte in the memory.
 187     @param withLength The length of memory.
 188     @param withDirection An I/O direction to be associated with the descriptor, which may affect the operation of the prepare and complete methods on some architectures.
 189     @result The created IOMemoryDescriptor on success, to be released by the caller, or zero on failure. */
 190
 191     static IOMemoryDescriptor * withPhysicalAddress(
 192                                 IOPhysicalAddress       address,
 193                                 IOByteCount             withLength,
 194                                 IODirection             withDirection );
 195
 196 /*! @function withRanges
 197     @abstract Create an IOMemoryDescriptor to describe one or more virtual ranges.
 198     @discussion This method creates and initializes an IOMemoryDescriptor for memory consisting of an array of virtual memory ranges each mapped into a specified source task.
 199     @param ranges An array of IOVirtualRange structures which specify the virtual ranges in the specified map which make up the memory to be described.
 200     @param withCount The member count of the ranges array.
 201     @param withDirection An I/O direction to be associated with the descriptor, which may affect the operation of the prepare and complete methods on some architectures.
 202     @param withTask The task each of the virtual ranges are mapped into.
 203     @param asReference If false, the IOMemoryDescriptor object will make a copy of the ranges array, otherwise, the array will be used in situ, avoiding an extra allocation.
 204     @result The created IOMemoryDescriptor on success, to be released by the caller, or zero on failure. */
 205
 206      static IOMemoryDescriptor * withRanges(IOVirtualRange * ranges,
 207                                             UInt32           withCount,
 208                                             IODirection      withDirection,
 209                                             task_t           withTask,
 210                                             bool             asReference = false);
 211
 212 /*! @function withOptions
 213     @abstract Master initialiser for all variants of memory descriptors.
 214     @discussion This method creates and initializes an IOMemoryDescriptor for memory it has three main variants: Virtual, Physical & mach UPL.  These variants are selected with the options parameter, see below.  This memory descriptor needs to be prepared before it can be used to extract data from the memory described.  However we temporarily have setup a mechanism that automatically prepares kernel_task memory descriptors at creation time.
 215
 216
 217     @param buffers A pointer to an array of IOVirtualRanges or IOPhysicalRanges if the options:type is Virtual or Physical.  For type UPL it is a upl_t returned by the mach/memory_object_types.h apis, primarily used internally by the UBC.
 218
 219     @param count options:type = Virtual or Physical count contains a count of the number of entires in the buffers array.  For options:type = UPL this field contains a total length.
 220
 221     @param offset Only used when options:type = UPL, in which case this field contains an offset for the memory within the buffers upl.
 222
 223     @param task Only used options:type = Virtual, The task each of the virtual ranges are mapped into.
 224
 225     @param options
 226         kIOMemoryDirectionMask (options:direction)      This nibble indicates the I/O direction to be associated with the descriptor, which may affect the operation of the prepare and complete methods on some architectures.
 227         kIOMemoryTypeMask (options:type)        kIOMemoryTypeVirtual, kIOMemoryTypePhysical, kIOMemoryTypeUPL Indicates that what type of memory basic memory descriptor to use.  This sub-field also controls the interpretation of the buffers, count, offset & task parameters.
 228         kIOMemoryAsReference    For options:type = Virtual or Physical this indicate that the memory descriptor need not copy the ranges array into local memory.  This is an optimisation to try to minimise unnecessary allocations.
 229         kIOMemoryBufferPageable Only used by the IOBufferMemoryDescriptor as an indication that the kernel virtual memory is in fact pageable and we need to use the kernel pageable submap rather than the default map.
 230         kIOMemoryNoAutoPrepare  Indicates that the temporary AutoPrepare of kernel_task memory should not be performed.
 231
 232     @param mapper Which IOMapper should be used to map the in-memory physical addresses into I/O space addresses.  Defaults to 0 which indicates that the system mapper is to be used, if present.
 233
 234     @result The created IOMemoryDescriptor on success, to be released by the caller, or zero on failure. */
 235
 236     static IOMemoryDescriptor *withOptions(void *       buffers,
 237                                            UInt32       count,
 238                                            UInt32       offset,
 239                                            task_t       task,
 240                                            IOOptionBits options,
 241                                            IOMapper *   mapper = 0);
 242
 243 /*! @function withPhysicalRanges
 244     @abstract Create an IOMemoryDescriptor to describe one or more physical ranges.
 245     @discussion  This method creates and initializes an IOMemoryDescriptor for memory consisting of an array of physical memory ranges.
 246     @param ranges An array of IOPhysicalRange structures which specify the physical ranges which make up the memory to be described.
 247     @param withCount The member count of the ranges array.
 248     @param withDirection An I/O direction to be associated with the descriptor, which may affect the operation of the prepare and complete methods on some architectures.
 249     @param asReference If false, the IOMemoryDescriptor object will make a copy of the ranges array, otherwise, the array will be used in situ, avoiding an extra allocation.
 250     @result The created IOMemoryDescriptor on success, to be released by the caller, or zero on failure. */
 251
 252     static IOMemoryDescriptor * withPhysicalRanges(
 253                                             IOPhysicalRange *   ranges,
 254                                             UInt32              withCount,
 255                                             IODirection         withDirection,
 256                                             bool                asReference = false);
 257
 258 /*! @function withSubRange
 259     @abstract Create an IOMemoryDescriptor to describe a subrange of an existing descriptor.
 260     @discussion  This method creates and initializes an IOMemoryDescriptor for memory consisting of a subrange of the specified memory descriptor. The parent memory descriptor is retained by the new descriptor.
 261     @param of The parent IOMemoryDescriptor of which a subrange is to be used for the new descriptor, which will be retained by the subrange IOMemoryDescriptor.
 262     @param offset A byte offset into the parent memory descriptor's memory.
 263     @param length The length of the subrange.
 264     @param withDirection An I/O direction to be associated with the descriptor, which may affect the operation of the prepare and complete methods on some architectures. This is used over the direction of the parent descriptor.
 265     @result The created IOMemoryDescriptor on success, to be released by the caller, or zero on failure. */
 266
 267     static IOMemoryDescriptor * withSubRange(IOMemoryDescriptor *of,
 268                                              IOByteCount offset,
 269                                              IOByteCount length,
 270                                              IODirection withDirection);
 271
 272 /*! @function initWithAddress
 273     @abstract Initialize or reinitialize an IOMemoryDescriptor to describe one virtual range of the kernel task.
 274     @discussion This method initializes an IOMemoryDescriptor for memory consisting of a single virtual memory range mapped into the kernel map. An IOMemoryDescriptor can be re-used by calling initWithAddress or initWithRanges again on an existing instance -- note this behavior is not commonly supported in other IOKit classes, although it is supported here.
 275     @param address The virtual address of the first byte in the memory.
 276     @param withLength The length of memory.
 277     @param withDirection An I/O direction to be associated with the descriptor, which may affect the operation of the prepare and complete methods on some architectures.
 278     @result true on success, false on failure. */
 279
 280     virtual bool initWithAddress(void *       address,
 281                                  IOByteCount  withLength,
 282                                  IODirection  withDirection) = 0;
 283
 284 /*! @function initWithAddress
 285     @abstract Initialize or reinitialize an IOMemoryDescriptor to describe one virtual range of the specified map.
 286     @discussion This method initializes an IOMemoryDescriptor for memory consisting of a single virtual memory range mapped into the specified map. An IOMemoryDescriptor can be re-used by calling initWithAddress or initWithRanges again on an existing instance -- note this behavior is not commonly supported in other IOKit classes, although it is supported here.
 287     @param address The virtual address of the first byte in the memory.
 288     @param withLength The length of memory.
 289     @param withDirection An I/O direction to be associated with the descriptor, which may affect the operation of the prepare and complete methods on some architectures.
 290     @param withTask The task the virtual ranges are mapped into.
 291     @result true on success, false on failure. */
 292
 293     virtual bool initWithAddress(vm_address_t address,
 294                                  IOByteCount  withLength,
 295                                  IODirection  withDirection,
 296                                  task_t       withTask) = 0;
 297
 298 /*! @function initWithPhysicalAddress
 299     @abstract Initialize or reinitialize an IOMemoryDescriptor to describe one physical range.
 300     @discussion This method initializes an IOMemoryDescriptor for memory consisting of a single physical memory range. An IOMemoryDescriptor can be re-used by calling initWithAddress or initWithRanges again on an existing instance -- note this behavior is not commonly supported in other IOKit classes, although it is supported here.
 301     @param address The physical address of the first byte in the memory.
 302     @param withLength The length of memory.
 303     @param withDirection An I/O direction to be associated with the descriptor, which may affect the operation of the prepare and complete methods on some architectures.
 304     @result true on success, false on failure. */
 305
 306     virtual bool initWithPhysicalAddress(
 307                                  IOPhysicalAddress      address,
 308                                  IOByteCount            withLength,
 309                                  IODirection            withDirection ) = 0;
 310
 311 /*! @function initWithRanges
 312     @abstract Initialize or reinitialize an IOMemoryDescriptor to describe one or more virtual ranges.
 313     @discussion This method initializes an IOMemoryDescriptor for memory consisting of an array of virtual memory ranges each mapped into a specified source task. An IOMemoryDescriptor can be re-used by calling initWithAddress or initWithRanges again on an existing instance -- note this behavior is not commonly supported in other IOKit classes, although it is supported here.
 314     @param ranges An array of IOVirtualRange structures which specify the virtual ranges in the specified map which make up the memory to be described.
 315     @param withCount The member count of the ranges array.
 316     @param withDirection An I/O direction to be associated with the descriptor, which may affect the operation of the prepare and complete methods on some architectures.
 317     @param withTask The task each of the virtual ranges are mapped into.
 318     @param asReference If false, the IOMemoryDescriptor object will make a copy of the ranges array, otherwise, the array will be used in situ, avoiding an extra allocation.
 319     @result true on success, false on failure. */
 320
 321     virtual bool initWithRanges(IOVirtualRange * ranges,
 322                                 UInt32           withCount,
 323                                 IODirection      withDirection,
 324                                 task_t           withTask,
 325                                 bool             asReference = false) = 0;
 326
 327 /*! @function initWithPhysicalRanges
 328     @abstract Initialize or reinitialize an IOMemoryDescriptor to describe one or more physical ranges.
 329     @discussion  This method initializes an IOMemoryDescriptor for memory consisting of an array of physical memory ranges. An IOMemoryDescriptor can be re-used by calling initWithAddress or initWithRanges again on an existing instance -- note this behavior is not commonly supported in other IOKit classes, although it is supported here.
 330     @param ranges An array of IOPhysicalRange structures which specify the physical ranges which make up the memory to be described.
 331     @param withCount The member count of the ranges array.
 332     @param withDirection An I/O direction to be associated with the descriptor, which may affect the operation of the prepare and complete methods on some architectures.
 333     @param asReference If false, the IOMemoryDescriptor object will make a copy of the ranges array, otherwise, the array will be used in situ, avoiding an extra allocation.
 334     @result true on success, false on failure. */
 335
 336     virtual bool initWithPhysicalRanges(IOPhysicalRange * ranges,
 337                                         UInt32           withCount,
 338                                         IODirection      withDirection,
 339                                         bool             asReference = false) = 0;
 340
 341 /*! @function getDirection
 342     @abstract Accessor to get the direction the memory descriptor was created with.
 343     @discussion This method returns the direction the memory descriptor was created with.
 344     @result The direction. */
 345
 346     virtual IODirection getDirection() const;
 347
 348 /*! @function getLength
 349     @abstract Accessor to get the length of the memory descriptor (over all its ranges).
 350     @discussion This method returns the total length of the memory described by the descriptor, ie. the sum of its ranges' lengths.
 351     @result The byte count. */
 352
 353     virtual IOByteCount getLength() const;
 354
 355 /*! @function setTag
 356     @abstract Set the tag for the memory descriptor.
 357     @discussion This method sets the tag for the memory descriptor. Tag bits are not interpreted by IOMemoryDescriptor.
 358     @param tag The tag. */
 359
 360     virtual void setTag( IOOptionBits tag );
 361
 362 /*! @function getTag
 363     @abstract Accessor to the retrieve the tag for the memory descriptor.
 364     @discussion This method returns the tag for the memory descriptor. Tag bits are not interpreted by IOMemoryDescriptor.
 365     @result The tag. */
 366
 367     virtual IOOptionBits getTag( void );
 368
 369 /*! @function readBytes
 370     @abstract Copy data from the memory descriptor's buffer to the specified buffer.
 371     @discussion This method copies data from the memory descriptor's memory at the given offset, to the caller's buffer.
 372     @param offset A byte offset into the memory descriptor's memory.
 373     @param bytes The caller supplied buffer to copy the data to.
 374     @param withLength The length of the data to copy.
 375     @result The number of bytes copied, zero will be returned if the specified offset is beyond the length of the descriptor. */
 376
 377     virtual IOByteCount readBytes(IOByteCount offset,
 378                                 void * bytes, IOByteCount withLength);
 379
 380 /*! @function writeBytes
 381     @abstract Copy data to the memory descriptor's buffer from the specified buffer.
 382     @discussion This method copies data to the memory descriptor's memory at the given offset, from the caller's buffer.
 383     @param offset A byte offset into the memory descriptor's memory.
 384     @param bytes The caller supplied buffer to copy the data from.
 385     @param withLength The length of the data to copy.
 386     @result The number of bytes copied, zero will be returned if the specified offset is beyond the length of the descriptor. */
 387
 388     virtual IOByteCount writeBytes(IOByteCount offset,
 389                                 const void * bytes, IOByteCount withLength);
 390
 391 /*! @function getPhysicalSegment
 392     @abstract Break a memory descriptor into its physically contiguous segments.
 393     @discussion This method returns the physical address of the byte at the given offset into the memory, and optionally the length of the physically contiguous segment from that offset.
 394     @param offset A byte offset into the memory whose physical address to return.
 395     @param length If non-zero, getPhysicalSegment will store here the length of the physically contiguous segement at the given offset.
 396     @result A physical address, or zero if the offset is beyond the length of the memory. */
 397
 398     virtual IOPhysicalAddress getPhysicalSegment(IOByteCount offset,
 399                                                  IOByteCount * length) = 0;
 400
 401 /*! @function getPhysicalAddress
 402     @abstract Return the physical address of the first byte in the memory.
 403     @discussion This method returns the physical address of the  first byte in the memory. It is most useful on memory known to be physically contiguous.
 404     @result A physical address. */
 405
 406     /* inline */ IOPhysicalAddress getPhysicalAddress();
 407         /* { return( getPhysicalSegment( 0, 0 )); } */
 408
 409     /* DEPRECATED */ /* USE INSTEAD: map(), readBytes(), writeBytes() */
 410     /* DEPRECATED */ virtual void * getVirtualSegment(IOByteCount offset,
 411     /* DEPRECATED */                                    IOByteCount * length) = 0;
 412     /* DEPRECATED */ /* USE INSTEAD: map(), readBytes(), writeBytes() */
 413
 414 /*! @function prepare
 415     @abstract Prepare the memory for an I/O transfer.
 416     @discussion This involves paging in the memory, if necessary, and wiring it down for the duration of the transfer.  The complete() method completes the processing of the memory after the I/O transfer finishes.  Note that the prepare call is not thread safe and it is expected that the client will more easily be able to guarantee single threading a particular memory descriptor.
 417     @param forDirection The direction of the I/O just completed, or kIODirectionNone for the direction specified by the memory descriptor.
 418     @result An IOReturn code. */
 419
 420     virtual IOReturn prepare(IODirection forDirection = kIODirectionNone) = 0;
 421
 422 /*! @function complete
 423     @abstract Complete processing of the memory after an I/O transfer finishes.
 424     @discussion This method should not be called unless a prepare was previously issued; the prepare() and complete() must occur in pairs, before and after an I/O transfer involving pageable memory.  In 10.3 or greater systems the direction argument to complete is not longer respected.  The direction is totally determined at prepare() time.
 425     @param forDirection DEPRECATED The direction of the I/O just completed, or kIODirectionNone for the direction specified by the memory descriptor.
 426     @result An IOReturn code. */
 427
 428     virtual IOReturn complete(IODirection forDirection = kIODirectionNone) = 0;
 429
 430     /*
 431      * Mapping functions.
 432      */
 433
 434 /*! @function map
 435     @abstract Maps a IOMemoryDescriptor into a task.
 436     @discussion This is the general purpose method to map all or part of the memory described by a memory descriptor into a task at any available address, or at a fixed address if possible. Caching & read-only options may be set for the mapping. The mapping is represented as a returned reference to a IOMemoryMap object, which may be shared if the mapping is compatible with an existing mapping of the IOMemoryDescriptor. The IOMemoryMap object returned should be released only when the caller has finished accessing the mapping, as freeing the object destroys the mapping.
 437     @param intoTask Sets the target task for the mapping. Pass kernel_task for the kernel address space.
 438     @param atAddress If a placed mapping is requested, atAddress specifies its address, and the kIOMapAnywhere should not be set. Otherwise, atAddress is ignored.
 439     @param options Mapping options are defined in IOTypes.h,<br>
 440         kIOMapAnywhere should be passed if the mapping can be created anywhere. If not set, the atAddress parameter sets the location of the mapping, if it is available in the target map.<br>
 441         kIOMapDefaultCache to inhibit the cache in I/O areas, kIOMapCopybackCache in general purpose RAM.<br>
 442         kIOMapInhibitCache, kIOMapWriteThruCache, kIOMapCopybackCache to set the appropriate caching.<br>
 443         kIOMapReadOnly to allow only read only accesses to the memory - writes will cause and access fault.<br>
 444         kIOMapReference will only succeed if the mapping already exists, and the IOMemoryMap object is just an extra reference, ie. no new mapping will be created.<br>
 445     @param offset Is a beginning offset into the IOMemoryDescriptor's memory where the mapping starts. Zero is the default to map all the memory.
 446     @param length Is the length of the mapping requested for a subset of the IOMemoryDescriptor. Zero is the default to map all the memory.
 447     @result A reference to an IOMemoryMap object representing the mapping, which can supply the virtual address of the mapping and other information. The mapping may be shared with multiple callers - multiple maps are avoided if a compatible one exists. The IOMemoryMap object returned should be released only when the caller has finished accessing the mapping, as freeing the object destroys the mapping. The IOMemoryMap instance also retains the IOMemoryDescriptor it maps while it exists. */
 448
 449     virtual IOMemoryMap *       map(
 450         task_t          intoTask,
 451         IOVirtualAddress        atAddress,
 452         IOOptionBits            options,
 453         IOByteCount             offset = 0,
 454         IOByteCount             length = 0 );
 455
 456 /*! @function map
 457     @abstract Maps a IOMemoryDescriptor into the kernel map.
 458     @discussion This is a shortcut method to map all the memory described by a memory descriptor into the kernel map at any available address. See the full version of the map method for further details.
 459     @param options Mapping options as in the full version of the map method, with kIOMapAnywhere assumed.
 460     @result See the full version of the map method. */
 461
 462     virtual IOMemoryMap *       map(
 463         IOOptionBits            options = 0 );
 464
 465 /*! @function setMapping
 466     @abstract Establishes an already existing mapping.
 467     @discussion This method tells the IOMemoryDescriptor about a mapping that exists, but was created elsewhere. It allows later callers of the map method to share this externally created mapping. The IOMemoryMap object returned is created to represent it. This method is not commonly needed.
 468     @param task Address space in which the mapping exists.
 469     @param mapAddress Virtual address of the mapping.
 470     @param options Caching and read-only attributes of the mapping.
 471     @result A IOMemoryMap object created to represent the mapping. */
 472
 473     virtual IOMemoryMap *       setMapping(
 474         task_t          task,
 475         IOVirtualAddress        mapAddress,
 476         IOOptionBits            options = 0 );
 477
 478     // Following methods are private implementation
 479
 480     // make virtual
 481     IOReturn redirect( task_t safeTask, bool redirect );
 482
 483     IOReturn handleFault(
 484         void *                  pager,
 485         vm_map_t                addressMap,
 486         IOVirtualAddress        address,
 487         IOByteCount             sourceOffset,
 488         IOByteCount             length,
 489         IOOptionBits            options );
 490
 491 protected:
 492     virtual IOMemoryMap *       makeMapping(
 493         IOMemoryDescriptor *    owner,
 494         task_t          intoTask,
 495         IOVirtualAddress        atAddress,
 496         IOOptionBits            options,
 497         IOByteCount             offset,
 498         IOByteCount             length );
 499
 500     virtual void                addMapping(
 501         IOMemoryMap *           mapping );
 502
 503     virtual void                removeMapping(
 504         IOMemoryMap *           mapping );
 505
 506     virtual IOReturn doMap(
 507         vm_map_t                addressMap,
 508         IOVirtualAddress *      atAddress,
 509         IOOptionBits            options,
 510         IOByteCount             sourceOffset = 0,
 511         IOByteCount             length = 0 );
 512
 513     virtual IOReturn doUnmap(
 514         vm_map_t                addressMap,
 515         IOVirtualAddress        logical,
 516         IOByteCount             length );
 517 };
 518
 519 /* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
 520
 521 /*! @class IOMemoryMap : public OSObject
 522     @abstract An abstract base class defining common methods for describing a memory mapping.
 523     @discussion The IOMemoryMap object represents a mapped range of memory, described by a IOMemoryDescriptor. The mapping may be in the kernel or a non-kernel task and has processor cache mode attributes. IOMemoryMap instances are created by IOMemoryDescriptor when it creates mappings in its map method, and returned to the caller. */
 524
 525 class IOMemoryMap : public OSObject
 526 {
 527     OSDeclareAbstractStructors(IOMemoryMap)
 528
 529 public:
 530 /*! @function getVirtualAddress
 531     @abstract Accessor to the virtual address of the first byte in the mapping.
 532     @discussion This method returns the virtual address of the first byte in the mapping.
 533     @result A virtual address. */
 534
 535     virtual IOVirtualAddress    getVirtualAddress() = 0;
 536
 537 /*! @function getPhysicalSegment
 538     @abstract Break a mapping into its physically contiguous segments.
 539     @discussion This method returns the physical address of the byte at the given offset into the mapping, and optionally the length of the physically contiguous segment from that offset. It functions similarly to IOMemoryDescriptor::getPhysicalSegment.
 540     @param offset A byte offset into the mapping whose physical address to return.
 541     @param length If non-zero, getPhysicalSegment will store here the length of the physically contiguous segement at the given offset.
 542     @result A physical address, or zero if the offset is beyond the length of the mapping. */
 543
 544     virtual IOPhysicalAddress   getPhysicalSegment(IOByteCount offset,
 545                                                    IOByteCount * length) = 0;
 546
 547 /*! @function getPhysicalAddress
 548     @abstract Return the physical address of the first byte in the mapping.
 549     @discussion This method returns the physical address of the  first byte in the mapping. It is most useful on mappings known to be physically contiguous.
 550     @result A physical address. */
 551
 552     /* inline */ IOPhysicalAddress getPhysicalAddress();
 553         /* { return( getPhysicalSegment( 0, 0 )); } */
 554
 555 /*! @function getLength
 556     @abstract Accessor to the length of the mapping.
 557     @discussion This method returns the length of the mapping.
 558     @result A byte count. */
 559
 560     virtual IOByteCount         getLength() = 0;
 561
 562 /*! @function getAddressTask
 563     @abstract Accessor to the task of the mapping.
 564     @discussion This method returns the mach task the mapping exists in.
 565     @result A mach task_t. */
 566
 567     virtual task_t              getAddressTask() = 0;
 568
 569 /*! @function getMemoryDescriptor
 570     @abstract Accessor to the IOMemoryDescriptor the mapping was created from.
 571     @discussion This method returns the IOMemoryDescriptor the mapping was created from.
 572     @result An IOMemoryDescriptor reference, which is valid while the IOMemoryMap object is retained. It should not be released by the caller. */
 573
 574     virtual IOMemoryDescriptor * getMemoryDescriptor() = 0;
 575
 576 /*! @function getMapOptions
 577     @abstract Accessor to the options the mapping was created with.
 578     @discussion This method returns the options to IOMemoryDescriptor::map the mapping was created with.
 579     @result Options for the mapping, including cache settings. */
 580
 581     virtual IOOptionBits        getMapOptions() = 0;
 582
 583 /*! @function unmap
 584     @abstract Force the IOMemoryMap to unmap, without destroying the object.
 585     @discussion IOMemoryMap instances will unmap themselves upon free, ie. when the last client with a reference calls release. This method forces the IOMemoryMap to destroy the mapping it represents, regardless of the number of clients. It is not generally used.
 586     @result An IOReturn code. */
 587
 588     virtual IOReturn            unmap() = 0;
 589
 590     virtual void                taskDied() = 0;
 591 };
 592
 593 /* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
 594
 595 // The following classes are private implementation of IOMemoryDescriptor - they
 596 // should not be referenced directly, just through the public API's in the
 597 // IOMemoryDescriptor class. For example, an IOGeneralMemoryDescriptor instance
 598 // might be created by IOMemoryDescriptor::withAddress(), but there should be
 599 // no need to reference as anything but a generic IOMemoryDescriptor *.
 600
 601 // Also these flags should not overlap with the options to
 602 //      IOMemoryDescriptor::initWithRanges(... IOOptionsBits options);
 603
 604 enum {
 605     kIOMemoryPreparedReadOnly   = 0x00008000,
 606 };
 607
 608 class IOGeneralMemoryDescriptor : public IOMemoryDescriptor
 609 {
 610     OSDeclareDefaultStructors(IOGeneralMemoryDescriptor);
 611
 612 protected:
 613     union {
 614         IOVirtualRange *  v;
 615         IOPhysicalRange * p;
 616     }                   _ranges;            /* list of address ranges */
 617     unsigned            _rangesCount;       /* number of address ranges in list */
 618     bool                _rangesIsAllocated; /* is list allocated by us? */
 619
 620     task_t              _task;               /* task where all ranges are mapped to */
 621
 622     union {
 623         IOVirtualRange  v;
 624         IOPhysicalRange p;
 625     }                   _singleRange;      /* storage space for a single range */
 626
 627     unsigned            _wireCount;        /* number of outstanding wires */
 628
 629     /* DEPRECATED */ vm_address_t _cachedVirtualAddress;  /* a cached virtual-to-physical */
 630
 631     /* DEPRECATED */ IOPhysicalAddress  _cachedPhysicalAddress;
 632
 633     bool                _initialized;      /* has superclass been initialized? */
 634
 635     virtual void free();
 636
 637
 638 private:
 639     // Internal API may be made virtual at some time in the future.
 640     IOReturn wireVirtual(IODirection forDirection);
 641
 642     /* DEPRECATED */ IOByteCount _position; /* absolute position over all ranges */
 643     /* DEPRECATED */ virtual void setPosition(IOByteCount position);
 644
 645 /*
 646  * DEPRECATED IOByteCount _positionAtIndex; // relative position within range #n
 647  *
 648  * Re-use the _positionAtIndex as a count of the number of pages in
 649  * this memory descriptor.  Convieniently vm_address_t is an unsigned integer
 650  * type so I can get away without having to change the type.
 651  */
 652     unsigned int                _pages;
 653
 654 /* DEPRECATED */ unsigned    _positionAtOffset;  //range #n in which position is now
 655
 656     OSData *_memoryEntries;
 657
 658     /* DEPRECATED */ vm_offset_t _kernPtrAligned;
 659     /* DEPRECATED */ unsigned    _kernPtrAtIndex;
 660     /* DEPRECATED */ IOByteCount  _kernSize;
 661
 662     /* DEPRECATED */ virtual void mapIntoKernel(unsigned rangeIndex);
 663     /* DEPRECATED */ virtual void unmapFromKernel();
 664
 665 public:
 666     /*
 667      * IOMemoryDescriptor required methods
 668      */
 669
 670     // Master initaliser
 671     virtual bool initWithOptions(void *         buffers,
 672                                  UInt32         count,
 673                                  UInt32         offset,
 674                                  task_t         task,
 675                                  IOOptionBits   options,
 676                                  IOMapper *     mapper = 0);
 677
 678     // Secondary initialisers
 679     virtual bool initWithAddress(void *         address,
 680                                  IOByteCount    withLength,
 681                                  IODirection    withDirection);
 682
 683     virtual bool initWithAddress(vm_address_t   address,
 684                                  IOByteCount    withLength,
 685                                  IODirection    withDirection,
 686                                  task_t         withTask);
 687
 688     virtual bool initWithPhysicalAddress(
 689                                  IOPhysicalAddress      address,
 690                                  IOByteCount            withLength,
 691                                  IODirection            withDirection );
 692
 693     virtual bool initWithRanges(        IOVirtualRange * ranges,
 694                                         UInt32           withCount,
 695                                         IODirection      withDirection,
 696                                         task_t           withTask,
 697                                         bool             asReference = false);
 698
 699     virtual bool initWithPhysicalRanges(IOPhysicalRange * ranges,
 700                                         UInt32           withCount,
 701                                         IODirection      withDirection,
 702                                         bool             asReference = false);
 703
 704     virtual IOPhysicalAddress getPhysicalSegment(IOByteCount offset,
 705                                                  IOByteCount * length);
 706
 707     virtual IOPhysicalAddress getSourceSegment(IOByteCount offset,
 708                                                IOByteCount * length);
 709
 710     /* DEPRECATED */ virtual void * getVirtualSegment(IOByteCount offset,
 711     /* DEPRECATED */                                    IOByteCount * length);
 712
 713     virtual IOReturn prepare(IODirection forDirection = kIODirectionNone);
 714
 715     virtual IOReturn complete(IODirection forDirection = kIODirectionNone);
 716
 717     virtual IOReturn doMap(
 718         vm_map_t                addressMap,
 719         IOVirtualAddress *      atAddress,
 720         IOOptionBits            options,
 721         IOByteCount             sourceOffset = 0,
 722         IOByteCount             length = 0 );
 723
 724     virtual IOReturn doUnmap(
 725         vm_map_t                addressMap,
 726         IOVirtualAddress        logical,
 727         IOByteCount             length );
 728     virtual bool serialize(OSSerialize *s) const;
 729 };
 730
 731 /* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
 732
 733 class IOSubMemoryDescriptor : public IOMemoryDescriptor
 734 {
 735     friend class IOMemoryDescriptor;
 736
 737     OSDeclareDefaultStructors(IOSubMemoryDescriptor);
 738
 739 protected:
 740     IOMemoryDescriptor * _parent;
 741     IOByteCount          _start;
 742
 743     virtual void free();
 744
 745     virtual bool initWithAddress(void *       address,
 746                                  IOByteCount    withLength,
 747                                  IODirection  withDirection);
 748
 749     virtual bool initWithAddress(vm_address_t address,
 750                                  IOByteCount    withLength,
 751                                  IODirection  withDirection,
 752                                  task_t       withTask);
 753
 754     virtual bool initWithPhysicalAddress(
 755                                  IOPhysicalAddress      address,
 756                                  IOByteCount            withLength,
 757                                  IODirection            withDirection );
 758
 759     virtual bool initWithRanges(        IOVirtualRange * ranges,
 760                                         UInt32           withCount,
 761                                         IODirection      withDirection,
 762                                         task_t           withTask,
 763                                         bool             asReference = false);
 764
 765     virtual bool initWithPhysicalRanges(IOPhysicalRange * ranges,
 766                                         UInt32           withCount,
 767                                         IODirection      withDirection,
 768                                         bool             asReference = false);
 769
 770     IOMemoryDescriptor::withAddress;
 771     IOMemoryDescriptor::withPhysicalAddress;
 772     IOMemoryDescriptor::withPhysicalRanges;
 773     IOMemoryDescriptor::withRanges;
 774     IOMemoryDescriptor::withSubRange;
 775
 776 public:
 777     /*
 778      * Initialize or reinitialize an IOSubMemoryDescriptor to describe
 779      * a subrange of an existing descriptor.
 780      *
 781      * An IOSubMemoryDescriptor can be re-used by calling initSubRange
 782      * again on an existing instance -- note that this behavior is not
 783      * commonly supported in other IOKit classes, although it is here.
 784      */
 785     virtual bool initSubRange( IOMemoryDescriptor * parent,
 786                                 IOByteCount offset, IOByteCount length,
 787                                 IODirection withDirection );
 788
 789     /*
 790      * IOMemoryDescriptor required methods
 791      */
 792
 793     virtual IOPhysicalAddress getPhysicalSegment(IOByteCount offset,
 794                                                  IOByteCount * length);
 795
 796     virtual IOPhysicalAddress getSourceSegment(IOByteCount offset,
 797                                                IOByteCount * length);
 798
 799     virtual IOByteCount readBytes(IOByteCount offset,
 800                                 void * bytes, IOByteCount withLength);
 801
 802     virtual IOByteCount writeBytes(IOByteCount offset,
 803                                 const void * bytes, IOByteCount withLength);
 804
 805     virtual void * getVirtualSegment(IOByteCount offset,
 806                                         IOByteCount * length);
 807
 808     virtual IOReturn prepare(IODirection forDirection = kIODirectionNone);
 809
 810     virtual IOReturn complete(IODirection forDirection = kIODirectionNone);
 811
 812     // make virtual
 813     IOReturn redirect( task_t safeTask, bool redirect );
 814
 815     virtual bool serialize(OSSerialize *s) const;
 816
 817 protected:
 818     virtual IOMemoryMap *       makeMapping(
 819         IOMemoryDescriptor *    owner,
 820         task_t          intoTask,
 821         IOVirtualAddress        atAddress,
 822         IOOptionBits            options,
 823         IOByteCount             offset,
 824         IOByteCount             length );
 825 };
 826
 827 /* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
 828
 829 #endif /* !_IOMEMORYDESCRIPTOR_H */