1============= 2Ioctl Numbers 3============= 4 519 October 1999 6 7Michael Elizabeth Chastain 8<mec@shout.net> 9 10If you are adding new ioctl's to the kernel, you should use the _IO 11macros 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 21system calls 'write' and 'read'. For example, a SET_FOO ioctl would 22be _IOW, although the kernel would actually read data from user space; 23a GET_FOO ioctl would be _IOR, although the kernel would actually write 24data to user space. 25 26The first argument to _IO, _IOW, _IOR, or _IOWR is an identifying letter 27or number from the table below. Because of the large number of drivers, 28many drivers share a partial letter with other drivers. 29 30If you are writing a driver for a new device and need a letter, pick an 31unused block with enough room for expansion: 32 to 256 ioctl commands 32should suffice. You can register the block by patching this file and 33submitting the patch through :doc:`usual patch submission process 34</process/submitting-patches>`. 35 36The second argument to _IO, _IOW, _IOR, or _IOWR is a sequence number 37to 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 39out of the kernel (e.g. 'int' or 'struct foo'). NOTE! Do NOT use 40sizeof(arg) as the third argument as this results in your ioctl thinking 41it passes an argument of type size_t. 42 43Some devices use their major number as the identifier; this is OK, as 44long as it is unique. Some devices are irregular and don't follow any 45convention at all. 46 47Following 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 65This table lists ioctls visible from userland, excluding ones from 66drivers/staging/. 67 68==== ===== ======================================================= ================================================================ 69Code Seq# Include File Comments 70 (hex) 71==== ===== ======================================================= ================================================================ 720x00 00-1F linux/fs.h conflict! 730x00 00-1F scsi/scsi_ioctl.h conflict! 740x00 00-1F linux/fb.h conflict! 750x00 00-1F linux/wavefront.h conflict! 760x02 all linux/fd.h 770x03 all linux/hdreg.h 780x04 D2-DC linux/umsdos_fs.h Dead since 2.6.11, but don't reuse these. 790x06 all linux/lp.h 800x07 9F-D0 linux/vmw_vmci_defs.h, uapi/linux/vm_sockets.h 810x09 all linux/raid/md_u.h 820x10 00-0F drivers/char/s390/vmcp.h 830x10 10-1F arch/s390/include/uapi/sclp_ctl.h 840x10 20-2F arch/s390/include/uapi/asm/hypfs.h 850x12 all linux/fs.h BLK* ioctls 86 linux/blkpg.h 87 linux/blkzoned.h 88 linux/blk-crypto.h 890x15 all linux/fs.h FS_IOC_* ioctls 900x1b all InfiniBand Subsystem 91 <http://infiniband.sourceforge.net/> 920x20 all drivers/cdrom/cm206.h 930x22 all scsi/sg.h 940x3E 00-0F linux/counter.h <mailto:linux-iio@vger.kernel.org> 95'!' 00-1F uapi/linux/seccomp.h 96'#' 00-3F IEEE 1394 Subsystem 97 Block for the entire subsystem 98'$' 00-0F linux/perf_counter.h, linux/perf_event.h 99'%' 00-0F include/uapi/linux/stm.h System Trace Module subsystem 100 <mailto:alexander.shishkin@linux.intel.com> 101'&' 00-07 drivers/firewire/nosy-user.h 102'*' 00-1F uapi/linux/user_events.h User Events Subsystem 103 <mailto:linux-trace-kernel@vger.kernel.org> 104'1' 00-1F linux/timepps.h PPS kit from Ulrich Windl 105 <ftp://ftp.de.kernel.org/pub/linux/daemons/ntp/PPS/> 106'2' 01-04 linux/i2o.h 107'3' 00-0F drivers/s390/char/raw3270.h conflict! 108'3' 00-1F linux/suspend_ioctls.h, conflict! 109 kernel/power/user.c 110'8' all SNP8023 advanced NIC card 111 <mailto:mcr@solidum.com> 112';' 64-7F linux/vfio.h 113';' 80-FF linux/iommufd.h 114'=' 00-3f uapi/linux/ptp_clock.h <mailto:richardcochran@gmail.com> 115'@' 00-0F linux/radeonfb.h conflict! 116'@' 00-0F drivers/video/aty/aty128fb.c conflict! 117'A' 00-1F linux/apm_bios.h conflict! 118'A' 00-0F linux/agpgart.h, conflict! 119 drivers/char/agp/compat_ioctl.h 120'A' 00-7F sound/asound.h conflict! 121'B' 00-1F linux/cciss_ioctl.h conflict! 122'B' 00-0F include/linux/pmu.h conflict! 123'B' C0-FF advanced bbus <mailto:maassen@uni-freiburg.de> 124'B' 00-0F xen/xenbus_dev.h conflict! 125'C' all linux/soundcard.h conflict! 126'C' 01-2F linux/capi.h conflict! 127'C' F0-FF drivers/net/wan/cosa.h conflict! 128'D' all arch/s390/include/asm/dasd.h 129'D' 40-5F drivers/scsi/dpt/dtpi_ioctl.h Dead since 2022 130'D' 05 drivers/scsi/pmcraid.h 131'E' all linux/input.h conflict! 132'E' 00-0F xen/evtchn.h conflict! 133'F' all linux/fb.h conflict! 134'F' 01-02 drivers/scsi/pmcraid.h conflict! 135'F' 20 drivers/video/fsl-diu-fb.h conflict! 136'F' 20 linux/ivtvfb.h conflict! 137'F' 20 linux/matroxfb.h conflict! 138'F' 20 drivers/video/aty/atyfb_base.c conflict! 139'F' 00-0F video/da8xx-fb.h conflict! 140'F' 80-8F linux/arcfb.h conflict! 141'F' DD video/sstfb.h conflict! 142'G' 00-3F drivers/misc/sgi-gru/grulib.h conflict! 143'G' 00-0F xen/gntalloc.h, xen/gntdev.h conflict! 144'H' 00-7F linux/hiddev.h conflict! 145'H' 00-0F linux/hidraw.h conflict! 146'H' 01 linux/mei.h conflict! 147'H' 02 linux/mei.h conflict! 148'H' 03 linux/mei.h conflict! 149'H' 00-0F sound/asound.h conflict! 150'H' 20-40 sound/asound_fm.h conflict! 151'H' 80-8F sound/sfnt_info.h conflict! 152'H' 10-8F sound/emu10k1.h conflict! 153'H' 10-1F sound/sb16_csp.h conflict! 154'H' 10-1F sound/hda_hwdep.h conflict! 155'H' 40-4F sound/hdspm.h conflict! 156'H' 40-4F sound/hdsp.h conflict! 157'H' 90 sound/usb/usx2y/usb_stream.h 158'H' 00-0F uapi/misc/habanalabs.h conflict! 159'H' A0 uapi/linux/usb/cdc-wdm.h 160'H' C0-F0 net/bluetooth/hci.h conflict! 161'H' C0-DF net/bluetooth/hidp/hidp.h conflict! 162'H' C0-DF net/bluetooth/cmtp/cmtp.h conflict! 163'H' C0-DF net/bluetooth/bnep/bnep.h conflict! 164'H' F1 linux/hid-roccat.h <mailto:erazor_de@users.sourceforge.net> 165'H' F8-FA sound/firewire.h 166'I' all linux/isdn.h conflict! 167'I' 00-0F drivers/isdn/divert/isdn_divert.h conflict! 168'I' 40-4F linux/mISDNif.h conflict! 169'K' all linux/kd.h 170'L' 00-1F linux/loop.h conflict! 171'L' 10-1F drivers/scsi/mpt3sas/mpt3sas_ctl.h conflict! 172'L' E0-FF linux/ppdd.h encrypted disk device driver 173 <http://linux01.gwdg.de/~alatham/ppdd.html> 174'M' all linux/soundcard.h conflict! 175'M' 01-16 mtd/mtd-abi.h conflict! 176 and drivers/mtd/mtdchar.c 177'M' 01-03 drivers/scsi/megaraid/megaraid_sas.h 178'M' 00-0F drivers/video/fsl-diu-fb.h conflict! 179'N' 00-1F drivers/usb/scanner.h 180'N' 40-7F drivers/block/nvme.c 181'N' 80-8F uapi/linux/ntsync.h NT synchronization primitives 182 <mailto:wine-devel@winehq.org> 183'O' 00-06 mtd/ubi-user.h UBI 184'P' all linux/soundcard.h conflict! 185'P' 60-6F sound/sscape_ioctl.h conflict! 186'P' 00-0F drivers/usb/class/usblp.c conflict! 187'P' 01-09 drivers/misc/pci_endpoint_test.c conflict! 188'P' 00-0F xen/privcmd.h conflict! 189'P' 00-05 linux/tps6594_pfsm.h conflict! 190'Q' all linux/soundcard.h 191'R' 00-1F linux/random.h conflict! 192'R' 01 linux/rfkill.h conflict! 193'R' 20-2F linux/trace_mmap.h 194'R' C0-DF net/bluetooth/rfcomm.h 195'R' E0 uapi/linux/fsl_mc.h 196'S' all linux/cdrom.h conflict! 197'S' 80-81 scsi/scsi_ioctl.h conflict! 198'S' 82-FF scsi/scsi.h conflict! 199'S' 00-7F sound/asequencer.h conflict! 200'T' all linux/soundcard.h conflict! 201'T' 00-AF sound/asound.h conflict! 202'T' all arch/x86/include/asm/ioctls.h conflict! 203'T' C0-DF linux/if_tun.h conflict! 204'U' all sound/asound.h conflict! 205'U' 00-CF linux/uinput.h conflict! 206'U' 00-EF linux/usbdevice_fs.h 207'U' C0-CF drivers/bluetooth/hci_uart.h 208'V' all linux/vt.h conflict! 209'V' all linux/videodev2.h conflict! 210'V' C0 linux/ivtvfb.h conflict! 211'V' C0 linux/ivtv.h conflict! 212'V' C0 media/si4713.h conflict! 213'W' 00-1F linux/watchdog.h conflict! 214'W' 00-1F linux/wanrouter.h conflict! (pre 3.9) 215'W' 00-3F sound/asound.h conflict! 216'W' 40-5F drivers/pci/switch/switchtec.c 217'W' 60-61 linux/watch_queue.h 218'X' all fs/xfs/xfs_fs.h, conflict! 219 fs/xfs/linux-2.6/xfs_ioctl32.h, 220 include/linux/falloc.h, 221 linux/fs.h, 222'X' all fs/ocfs2/ocfs_fs.h conflict! 223'X' 01 linux/pktcdvd.h conflict! 224'Z' 14-15 drivers/message/fusion/mptctl.h 225'[' 00-3F linux/usb/tmc.h USB Test and Measurement Devices 226 <mailto:gregkh@linuxfoundation.org> 227'a' all linux/atm*.h, linux/sonet.h ATM on linux 228 <http://lrcwww.epfl.ch/> 229'a' 00-0F drivers/crypto/qat/qat_common/adf_cfg_common.h conflict! qat driver 230'b' 00-FF conflict! bit3 vme host bridge 231 <mailto:natalia@nikhefk.nikhef.nl> 232'b' 00-0F linux/dma-buf.h conflict! 233'c' 00-7F linux/comstats.h conflict! 234'c' 00-7F linux/coda.h conflict! 235'c' 00-1F linux/chio.h conflict! 236'c' 80-9F arch/s390/include/asm/chsc.h conflict! 237'c' A0-AF arch/x86/include/asm/msr.h conflict! 238'd' 00-FF linux/char/drm/drm.h conflict! 239'd' 02-40 pcmcia/ds.h conflict! 240'd' F0-FF linux/digi1.h 241'e' all linux/digi1.h conflict! 242'f' 00-1F linux/ext2_fs.h conflict! 243'f' 00-1F linux/ext3_fs.h conflict! 244'f' 00-0F fs/jfs/jfs_dinode.h conflict! 245'f' 00-0F fs/ext4/ext4.h conflict! 246'f' 00-0F linux/fs.h conflict! 247'f' 00-0F fs/ocfs2/ocfs2_fs.h conflict! 248'f' 13-27 linux/fscrypt.h 249'f' 81-8F linux/fsverity.h 250'g' 00-0F linux/usb/gadgetfs.h 251'g' 20-2F linux/usb/g_printer.h 252'h' 00-7F conflict! Charon filesystem 253 <mailto:zapman@interlan.net> 254'h' 00-1F linux/hpet.h conflict! 255'h' 80-8F fs/hfsplus/ioctl.c 256'i' 00-3F linux/i2o-dev.h conflict! 257'i' 0B-1F linux/ipmi.h conflict! 258'i' 80-8F linux/i8k.h 259'i' 90-9F `linux/iio/*.h` IIO 260'j' 00-3F linux/joystick.h 261'k' 00-0F linux/spi/spidev.h conflict! 262'k' 00-05 video/kyro.h conflict! 263'k' 10-17 linux/hsi/hsi_char.h HSI character device 264'l' 00-3F linux/tcfs_fs.h transparent cryptographic file system 265 <http://web.archive.org/web/%2A/http://mikonos.dia.unisa.it/tcfs> 266'l' 40-7F linux/udf_fs_i.h in development: 267 <https://github.com/pali/udftools> 268'm' 00-09 linux/mmtimer.h conflict! 269'm' all linux/mtio.h conflict! 270'm' all linux/soundcard.h conflict! 271'm' all linux/synclink.h conflict! 272'm' 00-19 drivers/message/fusion/mptctl.h conflict! 273'm' 00 drivers/scsi/megaraid/megaraid_ioctl.h conflict! 274'n' 00-7F linux/ncp_fs.h and fs/ncpfs/ioctl.c 275'n' 80-8F uapi/linux/nilfs2_api.h NILFS2 276'n' E0-FF linux/matroxfb.h matroxfb 277'o' 00-1F fs/ocfs2/ocfs2_fs.h OCFS2 278'o' 00-03 mtd/ubi-user.h conflict! (OCFS2 and UBI overlaps) 279'o' 40-41 mtd/ubi-user.h UBI 280'o' 01-A1 `linux/dvb/*.h` DVB 281'p' 00-0F linux/phantom.h conflict! (OpenHaptics needs this) 282'p' 00-1F linux/rtc.h conflict! 283'p' 40-7F linux/nvram.h 284'p' 80-9F linux/ppdev.h user-space parport 285 <mailto:tim@cyberelk.net> 286'p' A1-A5 linux/pps.h LinuxPPS 287'p' B1-B3 linux/pps_gen.h LinuxPPS 288 <mailto:giometti@linux.it> 289'q' 00-1F linux/serio.h 290'q' 80-FF linux/telephony.h Internet PhoneJACK, Internet LineJACK 291 linux/ixjuser.h <http://web.archive.org/web/%2A/http://www.quicknet.net> 292'r' 00-1F linux/msdos_fs.h and fs/fat/dir.c 293's' all linux/cdk.h 294't' 00-7F linux/ppp-ioctl.h 295't' 80-8F linux/isdn_ppp.h 296't' 90-91 linux/toshiba.h toshiba and toshiba_acpi SMM 297'u' 00-1F linux/smb_fs.h gone 298'u' 00-2F linux/ublk_cmd.h conflict! 299'u' 20-3F linux/uvcvideo.h USB video class host driver 300'u' 40-4f linux/udmabuf.h userspace dma-buf misc device 301'v' 00-1F linux/ext2_fs.h conflict! 302'v' 00-1F linux/fs.h conflict! 303'v' 00-0F linux/sonypi.h conflict! 304'v' 00-0F media/v4l2-subdev.h conflict! 305'v' 20-27 arch/powerpc/include/uapi/asm/vas-api.h VAS API 306'v' C0-FF linux/meye.h conflict! 307'w' all CERN SCI driver 308'y' 00-1F packet based user level communications 309 <mailto:zapman@interlan.net> 310'z' 00-3F CAN bus card conflict! 311 <mailto:hdstich@connectu.ulm.circular.de> 312'z' 40-7F CAN bus card conflict! 313 <mailto:oe@port.de> 314'z' 10-4F drivers/s390/crypto/zcrypt_api.h conflict! 315'|' 00-7F linux/media.h 316'|' 80-9F samples/ Any sample and example drivers 3170x80 00-1F linux/fb.h 3180x81 00-1F linux/vduse.h 3190x89 00-06 arch/x86/include/asm/sockios.h 3200x89 0B-DF linux/sockios.h 3210x89 E0-EF linux/sockios.h SIOCPROTOPRIVATE range 3220x89 F0-FF linux/sockios.h SIOCDEVPRIVATE range 3230x8A 00-1F linux/eventpoll.h 3240x8B all linux/wireless.h 3250x8C 00-3F WiNRADiO driver 326 <http://www.winradio.com.au/> 3270x90 00 drivers/cdrom/sbpcd.h 3280x92 00-0F drivers/usb/mon/mon_bin.c 3290x93 60-7F linux/auto_fs.h 3300x94 all fs/btrfs/ioctl.h Btrfs filesystem 331 and linux/fs.h some lifted to vfs/generic 3320x97 00-7F fs/ceph/ioctl.h Ceph file system 3330x99 00-0F 537-Addinboard driver 334 <mailto:buk@buks.ipn.de> 3350x9A 00-0F include/uapi/fwctl/fwctl.h 3360xA0 all linux/sdp/sdp.h Industrial Device Project 337 <mailto:kenji@bitgate.com> 3380xA1 0 linux/vtpm_proxy.h TPM Emulator Proxy Driver 3390xA2 all uapi/linux/acrn.h ACRN hypervisor 3400xA3 80-8F Port ACL in development: 341 <mailto:tlewis@mindspring.com> 3420xA3 90-9F linux/dtlk.h 3430xA4 00-1F uapi/linux/tee.h Generic TEE subsystem 3440xA4 00-1F uapi/asm/sgx.h <mailto:linux-sgx@vger.kernel.org> 3450xA5 01-05 linux/surface_aggregator/cdev.h Microsoft Surface Platform System Aggregator 346 <mailto:luzmaximilian@gmail.com> 3470xA5 20-2F linux/surface_aggregator/dtx.h Microsoft Surface DTX driver 348 <mailto:luzmaximilian@gmail.com> 3490xAA 00-3F linux/uapi/linux/userfaultfd.h 3500xAB 00-1F linux/nbd.h 3510xAC 00-1F linux/raw.h 3520xAD 00 Netfilter device in development: 353 <mailto:rusty@rustcorp.com.au> 3540xAE 00-1F linux/kvm.h Kernel-based Virtual Machine 355 <mailto:kvm@vger.kernel.org> 3560xAE 40-FF linux/kvm.h Kernel-based Virtual Machine 357 <mailto:kvm@vger.kernel.org> 3580xAE 20-3F linux/nitro_enclaves.h Nitro Enclaves 3590xAF 00-1F linux/fsl_hypervisor.h Freescale hypervisor 3600xB0 all RATIO devices in development: 361 <mailto:vgo@ratio.de> 3620xB1 00-1F PPPoX 363 <mailto:mostrows@styx.uwaterloo.ca> 3640xB2 00 arch/powerpc/include/uapi/asm/papr-vpd.h powerpc/pseries VPD API 365 <mailto:linuxppc-dev> 3660xB2 01-02 arch/powerpc/include/uapi/asm/papr-sysparm.h powerpc/pseries system parameter API 367 <mailto:linuxppc-dev> 3680xB2 03-05 arch/powerpc/include/uapi/asm/papr-indices.h powerpc/pseries indices API 369 <mailto:linuxppc-dev> 3700xB2 06-07 arch/powerpc/include/uapi/asm/papr-platform-dump.h powerpc/pseries Platform Dump API 371 <mailto:linuxppc-dev> 3720xB2 08 powerpc/include/uapi/asm/papr-physical-attestation.h powerpc/pseries Physical Attestation API 373 <mailto:linuxppc-dev> 3740xB3 00 linux/mmc/ioctl.h 3750xB4 00-0F linux/gpio.h <mailto:linux-gpio@vger.kernel.org> 3760xB5 00-0F uapi/linux/rpmsg.h <mailto:linux-remoteproc@vger.kernel.org> 3770xB6 all linux/fpga-dfl.h 3780xB7 all uapi/linux/remoteproc_cdev.h <mailto:linux-remoteproc@vger.kernel.org> 3790xB7 all uapi/linux/nsfs.h <mailto:Andrei Vagin <avagin@openvz.org>> 3800xB8 01-02 uapi/misc/mrvl_cn10k_dpi.h Marvell CN10K DPI driver 3810xB8 all uapi/linux/mshv.h Microsoft Hyper-V /dev/mshv driver 382 <mailto:linux-hyperv@vger.kernel.org> 3830xC0 00-0F linux/usb/iowarrior.h 3840xCA 00-0F uapi/misc/cxl.h Dead since 6.15 3850xCA 10-2F uapi/misc/ocxl.h 3860xCA 80-BF uapi/scsi/cxlflash_ioctl.h Dead since 6.15 3870xCB 00-1F CBM serial IEC bus in development: 388 <mailto:michael.klein@puffin.lb.shuttle.de> 3890xCC 00-0F drivers/misc/ibmvmc.h pseries VMC driver 3900xCD 01 linux/reiserfs_fs.h Dead since 6.13 3910xCE 01-02 uapi/linux/cxl_mem.h Compute Express Link Memory Devices 3920xCF 02 fs/smb/client/cifs_ioctl.h 3930xDB 00-0F drivers/char/mwave/mwavepub.h 3940xDD 00-3F ZFCP device driver see drivers/s390/scsi/ 395 <mailto:aherrman@de.ibm.com> 3960xE5 00-3F linux/fuse.h 3970xEC 00-01 drivers/platform/chrome/cros_ec_dev.h ChromeOS EC driver 3980xEE 00-09 uapi/linux/pfrut.h Platform Firmware Runtime Update and Telemetry 3990xF3 00-3F drivers/usb/misc/sisusbvga/sisusb.h sisfb (in development) 400 <mailto:thomas@winischhofer.net> 4010xF6 all LTTng Linux Trace Toolkit Next Generation 402 <mailto:mathieu.desnoyers@efficios.com> 4030xF8 all arch/x86/include/uapi/asm/amd_hsmp.h AMD HSMP EPYC system management interface driver 404 <mailto:nchatrad@amd.com> 4050xFD all linux/dm-ioctl.h 4060xFE all linux/isst_if.h 407==== ===== ======================================================= ================================================================ 408