Documentation/ioctl/ioctl-number.rst

   1 =============
   2 Ioctl Numbers
   3 =============
   4
   5 19 October 1999
   6
   7 Michael Elizabeth Chastain
   8 <mec@shout.net>
   9
  10 If you are adding new ioctl's to the kernel, you should use the _IO
  11 macros defined in <linux/ioctl.h>:
  12
  13     ====== == ============================================
  14     _IO    an ioctl with no parameters
  15     _IOW   an ioctl with write parameters (copy_from_user)
  16     _IOR   an ioctl with read parameters  (copy_to_user)
  17     _IOWR  an ioctl with both write and read parameters.
  18     ====== == ============================================
  19
  20 'Write' and 'read' are from the user's point of view, just like the
  21 system calls 'write' and 'read'.  For example, a SET_FOO ioctl would
  22 be _IOW, although the kernel would actually read data from user space;
  23 a GET_FOO ioctl would be _IOR, although the kernel would actually write
  24 data to user space.
  25
  26 The first argument to _IO, _IOW, _IOR, or _IOWR is an identifying letter
  27 or number from the table below.  Because of the large number of drivers,
  28 many drivers share a partial letter with other drivers.
  29
  30 If you are writing a driver for a new device and need a letter, pick an
  31 unused block with enough room for expansion: 32 to 256 ioctl commands.
  32 You can register the block by patching this file and submitting the
  33 patch to Linus Torvalds.  Or you can e-mail me at <mec@shout.net> and
  34 I'll register one for you.
  35
  36 The second argument to _IO, _IOW, _IOR, or _IOWR is a sequence number
  37 to distinguish ioctls from each other.  The third argument to _IOW,
  38 _IOR, or _IOWR is the type of the data going into the kernel or coming
  39 out of the kernel (e.g.  'int' or 'struct foo').  NOTE!  Do NOT use
  40 sizeof(arg) as the third argument as this results in your ioctl thinking
  41 it passes an argument of type size_t.
  42
  43 Some devices use their major number as the identifier; this is OK, as
  44 long as it is unique.  Some devices are irregular and don't follow any
  45 convention at all.
  46
  47 Following this convention is good because:
  48
  49 (1) Keeping the ioctl's globally unique helps error checking:
  50     if a program calls an ioctl on the wrong device, it will get an
  51     error rather than some unexpected behaviour.
  52
  53 (2) The 'strace' build procedure automatically finds ioctl numbers
  54     defined with _IO, _IOW, _IOR, or _IOWR.
  55
  56 (3) 'strace' can decode numbers back into useful names when the
  57     numbers are unique.
  58
  59 (4) People looking for ioctls can grep for them more easily when
  60     this convention is used to define the ioctl numbers.
  61
  62 (5) When following the convention, the driver code can use generic
  63     code to copy the parameters between user and kernel space.
  64
  65 This table lists ioctls visible from user land for Linux/x86.  It contains
  66 most drivers up to 2.6.31, but I know I am missing some.  There has been
  67 no attempt to list non-X86 architectures or ioctls from drivers/staging/.
  68
  69 ====  =====  ======================================================= ================================================================
  70 Code  Seq#    Include File                                           Comments
  71       (hex)
  72 ====  =====  ======================================================= ================================================================
  73 0x00  00-1F  linux/fs.h                                              conflict!
  74 0x00  00-1F  scsi/scsi_ioctl.h                                       conflict!
  75 0x00  00-1F  linux/fb.h                                              conflict!
  76 0x00  00-1F  linux/wavefront.h                                       conflict!
  77 0x02  all    linux/fd.h
  78 0x03  all    linux/hdreg.h
  79 0x04  D2-DC  linux/umsdos_fs.h                                       Dead since 2.6.11, but don't reuse these.
  80 0x06  all    linux/lp.h
  81 0x09  all    linux/raid/md_u.h
  82 0x10  00-0F  drivers/char/s390/vmcp.h
  83 0x10  10-1F  arch/s390/include/uapi/sclp_ctl.h
  84 0x10  20-2F  arch/s390/include/uapi/asm/hypfs.h
  85 0x12  all    linux/fs.h
  86              linux/blkpg.h
  87 0x1b  all                                                            InfiniBand Subsystem
  88                                                                      <http://infiniband.sourceforge.net/>
  89 0x20  all    drivers/cdrom/cm206.h
  90 0x22  all    scsi/sg.h
  91 '!'   00-1F  uapi/linux/seccomp.h
  92 '#'   00-3F                                                          IEEE 1394 Subsystem
  93                                                                      Block for the entire subsystem
  94 '$'   00-0F  linux/perf_counter.h, linux/perf_event.h
  95 '%'   00-0F  include/uapi/linux/stm.h                                System Trace Module subsystem
  96                                                                      <mailto:alexander.shishkin@linux.intel.com>
  97 '&'   00-07  drivers/firewire/nosy-user.h
  98 '1'   00-1F  linux/timepps.h                                         PPS kit from Ulrich Windl
  99                                                                      <ftp://ftp.de.kernel.org/pub/linux/daemons/ntp/PPS/>
 100 '2'   01-04  linux/i2o.h
 101 '3'   00-0F  drivers/s390/char/raw3270.h                             conflict!
 102 '3'   00-1F  linux/suspend_ioctls.h,                                 conflict!
 103              kernel/power/user.c
 104 '8'   all                                                            SNP8023 advanced NIC card
 105                                                                      <mailto:mcr@solidum.com>
 106 ';'   64-7F  linux/vfio.h
 107 '@'   00-0F  linux/radeonfb.h                                        conflict!
 108 '@'   00-0F  drivers/video/aty/aty128fb.c                            conflict!
 109 'A'   00-1F  linux/apm_bios.h                                        conflict!
 110 'A'   00-0F  linux/agpgart.h,                                        conflict!
 111              drivers/char/agp/compat_ioctl.h
 112 'A'   00-7F  sound/asound.h                                          conflict!
 113 'B'   00-1F  linux/cciss_ioctl.h                                     conflict!
 114 'B'   00-0F  include/linux/pmu.h                                     conflict!
 115 'B'   C0-FF  advanced bbus                                           <mailto:maassen@uni-freiburg.de>
 116 'C'   all    linux/soundcard.h                                       conflict!
 117 'C'   01-2F  linux/capi.h                                            conflict!
 118 'C'   F0-FF  drivers/net/wan/cosa.h                                  conflict!
 119 'D'   all    arch/s390/include/asm/dasd.h
 120 'D'   40-5F  drivers/scsi/dpt/dtpi_ioctl.h
 121 'D'   05     drivers/scsi/pmcraid.h
 122 'E'   all    linux/input.h                                           conflict!
 123 'E'   00-0F  xen/evtchn.h                                            conflict!
 124 'F'   all    linux/fb.h                                              conflict!
 125 'F'   01-02  drivers/scsi/pmcraid.h                                  conflict!
 126 'F'   20     drivers/video/fsl-diu-fb.h                              conflict!
 127 'F'   20     drivers/video/intelfb/intelfb.h                         conflict!
 128 'F'   20     linux/ivtvfb.h                                          conflict!
 129 'F'   20     linux/matroxfb.h                                        conflict!
 130 'F'   20     drivers/video/aty/atyfb_base.c                          conflict!
 131 'F'   00-0F  video/da8xx-fb.h                                        conflict!
 132 'F'   80-8F  linux/arcfb.h                                           conflict!
 133 'F'   DD     video/sstfb.h                                           conflict!
 134 'G'   00-3F  drivers/misc/sgi-gru/grulib.h                           conflict!
 135 'G'   00-0F  linux/gigaset_dev.h                                     conflict!
 136 'H'   00-7F  linux/hiddev.h                                          conflict!
 137 'H'   00-0F  linux/hidraw.h                                          conflict!
 138 'H'   01     linux/mei.h                                             conflict!
 139 'H'   02     linux/mei.h                                             conflict!
 140 'H'   03     linux/mei.h                                             conflict!
 141 'H'   00-0F  sound/asound.h                                          conflict!
 142 'H'   20-40  sound/asound_fm.h                                       conflict!
 143 'H'   80-8F  sound/sfnt_info.h                                       conflict!
 144 'H'   10-8F  sound/emu10k1.h                                         conflict!
 145 'H'   10-1F  sound/sb16_csp.h                                        conflict!
 146 'H'   10-1F  sound/hda_hwdep.h                                       conflict!
 147 'H'   40-4F  sound/hdspm.h                                           conflict!
 148 'H'   40-4F  sound/hdsp.h                                            conflict!
 149 'H'   90     sound/usb/usx2y/usb_stream.h
 150 'H'   A0     uapi/linux/usb/cdc-wdm.h
 151 'H'   C0-F0  net/bluetooth/hci.h                                     conflict!
 152 'H'   C0-DF  net/bluetooth/hidp/hidp.h                               conflict!
 153 'H'   C0-DF  net/bluetooth/cmtp/cmtp.h                               conflict!
 154 'H'   C0-DF  net/bluetooth/bnep/bnep.h                               conflict!
 155 'H'   F1     linux/hid-roccat.h                                      <mailto:erazor_de@users.sourceforge.net>
 156 'H'   F8-FA  sound/firewire.h
 157 'I'   all    linux/isdn.h                                            conflict!
 158 'I'   00-0F  drivers/isdn/divert/isdn_divert.h                       conflict!
 159 'I'   40-4F  linux/mISDNif.h                                         conflict!
 160 'J'   00-1F  drivers/scsi/gdth_ioctl.h
 161 'K'   all    linux/kd.h
 162 'L'   00-1F  linux/loop.h                                            conflict!
 163 'L'   10-1F  drivers/scsi/mpt3sas/mpt3sas_ctl.h                      conflict!
 164 'L'   20-2F  linux/lightnvm.h
 165 'L'   E0-FF  linux/ppdd.h                                            encrypted disk device driver
 166                                                                      <http://linux01.gwdg.de/~alatham/ppdd.html>
 167 'M'   all    linux/soundcard.h                                       conflict!
 168 'M'   01-16  mtd/mtd-abi.h                                           conflict!
 169       and    drivers/mtd/mtdchar.c
 170 'M'   01-03  drivers/scsi/megaraid/megaraid_sas.h
 171 'M'   00-0F  drivers/video/fsl-diu-fb.h                              conflict!
 172 'N'   00-1F  drivers/usb/scanner.h
 173 'N'   40-7F  drivers/block/nvme.c
 174 'O'   00-06  mtd/ubi-user.h                                          UBI
 175 'P'   all    linux/soundcard.h                                       conflict!
 176 'P'   60-6F  sound/sscape_ioctl.h                                    conflict!
 177 'P'   00-0F  drivers/usb/class/usblp.c                               conflict!
 178 'P'   01-09  drivers/misc/pci_endpoint_test.c                        conflict!
 179 'Q'   all    linux/soundcard.h
 180 'R'   00-1F  linux/random.h                                          conflict!
 181 'R'   01     linux/rfkill.h                                          conflict!
 182 'R'   C0-DF  net/bluetooth/rfcomm.h
 183 'S'   all    linux/cdrom.h                                           conflict!
 184 'S'   80-81  scsi/scsi_ioctl.h                                       conflict!
 185 'S'   82-FF  scsi/scsi.h                                             conflict!
 186 'S'   00-7F  sound/asequencer.h                                      conflict!
 187 'T'   all    linux/soundcard.h                                       conflict!
 188 'T'   00-AF  sound/asound.h                                          conflict!
 189 'T'   all    arch/x86/include/asm/ioctls.h                           conflict!
 190 'T'   C0-DF  linux/if_tun.h                                          conflict!
 191 'U'   all    sound/asound.h                                          conflict!
 192 'U'   00-CF  linux/uinput.h                                          conflict!
 193 'U'   00-EF  linux/usbdevice_fs.h
 194 'U'   C0-CF  drivers/bluetooth/hci_uart.h
 195 'V'   all    linux/vt.h                                              conflict!
 196 'V'   all    linux/videodev2.h                                       conflict!
 197 'V'   C0     linux/ivtvfb.h                                          conflict!
 198 'V'   C0     linux/ivtv.h                                            conflict!
 199 'V'   C0     media/davinci/vpfe_capture.h                            conflict!
 200 'V'   C0     media/si4713.h                                          conflict!
 201 'W'   00-1F  linux/watchdog.h                                        conflict!
 202 'W'   00-1F  linux/wanrouter.h                                       conflict! (pre 3.9)
 203 'W'   00-3F  sound/asound.h                                          conflict!
 204 'W'   40-5F  drivers/pci/switch/switchtec.c
 205 'X'   all    fs/xfs/xfs_fs.h,                                        conflict!
 206              fs/xfs/linux-2.6/xfs_ioctl32.h,
 207              include/linux/falloc.h,
 208              linux/fs.h,
 209 'X'   all    fs/ocfs2/ocfs_fs.h                                      conflict!
 210 'X'   01     linux/pktcdvd.h                                         conflict!
 211 'Y'   all    linux/cyclades.h
 212 'Z'   14-15  drivers/message/fusion/mptctl.h
 213 '['   00-3F  linux/usb/tmc.h                                         USB Test and Measurement Devices
 214                                                                      <mailto:gregkh@linuxfoundation.org>
 215 'a'   all    linux/atm*.h, linux/sonet.h                             ATM on linux
 216                                                                      <http://lrcwww.epfl.ch/>
 217 'a'   00-0F  drivers/crypto/qat/qat_common/adf_cfg_common.h          conflict! qat driver
 218 'b'   00-FF                                                          conflict! bit3 vme host bridge
 219                                                                      <mailto:natalia@nikhefk.nikhef.nl>
 220 'c'   all    linux/cm4000_cs.h                                       conflict!
 221 'c'   00-7F  linux/comstats.h                                        conflict!
 222 'c'   00-7F  linux/coda.h                                            conflict!
 223 'c'   00-1F  linux/chio.h                                            conflict!
 224 'c'   80-9F  arch/s390/include/asm/chsc.h                            conflict!
 225 'c'   A0-AF  arch/x86/include/asm/msr.h conflict!
 226 'd'   00-FF  linux/char/drm/drm.h                                    conflict!
 227 'd'   02-40  pcmcia/ds.h                                             conflict!
 228 'd'   F0-FF  linux/digi1.h
 229 'e'   all    linux/digi1.h                                           conflict!
 230 'f'   00-1F  linux/ext2_fs.h                                         conflict!
 231 'f'   00-1F  linux/ext3_fs.h                                         conflict!
 232 'f'   00-0F  fs/jfs/jfs_dinode.h                                     conflict!
 233 'f'   00-0F  fs/ext4/ext4.h                                          conflict!
 234 'f'   00-0F  linux/fs.h                                              conflict!
 235 'f'   00-0F  fs/ocfs2/ocfs2_fs.h                                     conflict!
 236 'g'   00-0F  linux/usb/gadgetfs.h
 237 'g'   20-2F  linux/usb/g_printer.h
 238 'h'   00-7F                                                          conflict! Charon filesystem
 239                                                                      <mailto:zapman@interlan.net>
 240 'h'   00-1F  linux/hpet.h                                            conflict!
 241 'h'   80-8F  fs/hfsplus/ioctl.c
 242 'i'   00-3F  linux/i2o-dev.h                                         conflict!
 243 'i'   0B-1F  linux/ipmi.h                                            conflict!
 244 'i'   80-8F  linux/i8k.h
 245 'j'   00-3F  linux/joystick.h
 246 'k'   00-0F  linux/spi/spidev.h                                      conflict!
 247 'k'   00-05  video/kyro.h                                            conflict!
 248 'k'   10-17  linux/hsi/hsi_char.h                                    HSI character device
 249 'l'   00-3F  linux/tcfs_fs.h                                         transparent cryptographic file system
 250                                                                      <http://web.archive.org/web/%2A/http://mikonos.dia.unisa.it/tcfs>
 251 'l'   40-7F  linux/udf_fs_i.h                                        in development:
 252                                                                      <http://sourceforge.net/projects/linux-udf/>
 253 'm'   00-09  linux/mmtimer.h                                         conflict!
 254 'm'   all    linux/mtio.h                                            conflict!
 255 'm'   all    linux/soundcard.h                                       conflict!
 256 'm'   all    linux/synclink.h                                        conflict!
 257 'm'   00-19  drivers/message/fusion/mptctl.h                         conflict!
 258 'm'   00     drivers/scsi/megaraid/megaraid_ioctl.h                  conflict!
 259 'n'   00-7F  linux/ncp_fs.h and fs/ncpfs/ioctl.c
 260 'n'   80-8F  uapi/linux/nilfs2_api.h                                 NILFS2
 261 'n'   E0-FF  linux/matroxfb.h                                        matroxfb
 262 'o'   00-1F  fs/ocfs2/ocfs2_fs.h                                     OCFS2
 263 'o'   00-03  mtd/ubi-user.h                                          conflict! (OCFS2 and UBI overlaps)
 264 'o'   40-41  mtd/ubi-user.h                                          UBI
 265 'o'   01-A1  `linux/dvb/*.h`                                         DVB
 266 'p'   00-0F  linux/phantom.h                                         conflict! (OpenHaptics needs this)
 267 'p'   00-1F  linux/rtc.h                                             conflict!
 268 'p'   00-3F  linux/mc146818rtc.h                                     conflict!
 269 'p'   40-7F  linux/nvram.h
 270 'p'   80-9F  linux/ppdev.h                                           user-space parport
 271                                                                      <mailto:tim@cyberelk.net>
 272 'p'   A1-A5  linux/pps.h                                             LinuxPPS
 273                                                                      <mailto:giometti@linux.it>
 274 'q'   00-1F  linux/serio.h
 275 'q'   80-FF  linux/telephony.h                                       Internet PhoneJACK, Internet LineJACK
 276              linux/ixjuser.h                                         <http://web.archive.org/web/%2A/http://www.quicknet.net>
 277 'r'   00-1F  linux/msdos_fs.h and fs/fat/dir.c
 278 's'   all    linux/cdk.h
 279 't'   00-7F  linux/ppp-ioctl.h
 280 't'   80-8F  linux/isdn_ppp.h
 281 't'   90-91  linux/toshiba.h                                         toshiba and toshiba_acpi SMM
 282 'u'   00-1F  linux/smb_fs.h                                          gone
 283 'u'   20-3F  linux/uvcvideo.h                                        USB video class host driver
 284 'u'   40-4f  linux/udmabuf.h                                         userspace dma-buf misc device
 285 'v'   00-1F  linux/ext2_fs.h                                         conflict!
 286 'v'   00-1F  linux/fs.h                                              conflict!
 287 'v'   00-0F  linux/sonypi.h                                          conflict!
 288 'v'   00-0F  media/v4l2-subdev.h                                     conflict!
 289 'v'   C0-FF  linux/meye.h                                            conflict!
 290 'w'   all                                                            CERN SCI driver
 291 'y'   00-1F                                                          packet based user level communications
 292                                                                      <mailto:zapman@interlan.net>
 293 'z'   00-3F                                                          CAN bus card conflict!
 294                                                                      <mailto:hdstich@connectu.ulm.circular.de>
 295 'z'   40-7F                                                          CAN bus card conflict!
 296                                                                      <mailto:oe@port.de>
 297 'z'   10-4F  drivers/s390/crypto/zcrypt_api.h                        conflict!
 298 '|'   00-7F  linux/media.h
 299 0x80  00-1F  linux/fb.h
 300 0x89  00-06  arch/x86/include/asm/sockios.h
 301 0x89  0B-DF  linux/sockios.h
 302 0x89  E0-EF  linux/sockios.h                                         SIOCPROTOPRIVATE range
 303 0x89  E0-EF  linux/dn.h                                              PROTOPRIVATE range
 304 0x89  F0-FF  linux/sockios.h                                         SIOCDEVPRIVATE range
 305 0x8B  all    linux/wireless.h
 306 0x8C  00-3F                                                          WiNRADiO driver
 307                                                                      <http://www.winradio.com.au/>
 308 0x90  00     drivers/cdrom/sbpcd.h
 309 0x92  00-0F  drivers/usb/mon/mon_bin.c
 310 0x93  60-7F  linux/auto_fs.h
 311 0x94  all    fs/btrfs/ioctl.h                                        Btrfs filesystem
 312              and linux/fs.h                                          some lifted to vfs/generic
 313 0x97  00-7F  fs/ceph/ioctl.h                                         Ceph file system
 314 0x99  00-0F                                                          537-Addinboard driver
 315                                                                      <mailto:buk@buks.ipn.de>
 316 0xA0  all    linux/sdp/sdp.h                                         Industrial Device Project
 317                                                                      <mailto:kenji@bitgate.com>
 318 0xA1  0      linux/vtpm_proxy.h                                      TPM Emulator Proxy Driver
 319 0xA3  80-8F                                                          Port ACL  in development:
 320                                                                      <mailto:tlewis@mindspring.com>
 321 0xA3  90-9F  linux/dtlk.h
 322 0xA4  00-1F  uapi/linux/tee.h                                        Generic TEE subsystem
 323 0xAA  00-3F  linux/uapi/linux/userfaultfd.h
 324 0xAB  00-1F  linux/nbd.h
 325 0xAC  00-1F  linux/raw.h
 326 0xAD  00                                                             Netfilter device in development:
 327                                                                      <mailto:rusty@rustcorp.com.au>
 328 0xAE  all    linux/kvm.h                                             Kernel-based Virtual Machine
 329                                                                      <mailto:kvm@vger.kernel.org>
 330 0xAF  00-1F  linux/fsl_hypervisor.h                                  Freescale hypervisor
 331 0xB0  all                                                            RATIO devices in development:
 332                                                                      <mailto:vgo@ratio.de>
 333 0xB1  00-1F                                                          PPPoX
 334                                                                      <mailto:mostrows@styx.uwaterloo.ca>
 335 0xB3  00     linux/mmc/ioctl.h
 336 0xB4  00-0F  linux/gpio.h                                            <mailto:linux-gpio@vger.kernel.org>
 337 0xB5  00-0F  uapi/linux/rpmsg.h                                      <mailto:linux-remoteproc@vger.kernel.org>
 338 0xB6  all    linux/fpga-dfl.h
 339 0xC0  00-0F  linux/usb/iowarrior.h
 340 0xCA  00-0F  uapi/misc/cxl.h
 341 0xCA  10-2F  uapi/misc/ocxl.h
 342 0xCA  80-BF  uapi/scsi/cxlflash_ioctl.h
 343 0xCB  00-1F                                                          CBM serial IEC bus in development:
 344                                                                      <mailto:michael.klein@puffin.lb.shuttle.de>
 345 0xCC  00-0F  drivers/misc/ibmvmc.h                                   pseries VMC driver
 346 0xCD  01     linux/reiserfs_fs.h
 347 0xCF  02     fs/cifs/ioctl.c
 348 0xDB  00-0F  drivers/char/mwave/mwavepub.h
 349 0xDD  00-3F                                                          ZFCP device driver see drivers/s390/scsi/
 350                                                                      <mailto:aherrman@de.ibm.com>
 351 0xE5  00-3F  linux/fuse.h
 352 0xEC  00-01  drivers/platform/chrome/cros_ec_dev.h                   ChromeOS EC driver
 353 0xF3  00-3F  drivers/usb/misc/sisusbvga/sisusb.h                     sisfb (in development)
 354                                                                      <mailto:thomas@winischhofer.net>
 355 0xF4  00-1F  video/mbxfb.h                                           mbxfb
 356                                                                      <mailto:raph@8d.com>
 357 0xF6  all                                                            LTTng Linux Trace Toolkit Next Generation
 358                                                                      <mailto:mathieu.desnoyers@efficios.com>
 359 0xFD  all    linux/dm-ioctl.h
 360 0xFE  all    linux/isst_if.h
 361 ====  =====  ======================================================= ================================================================