xref: /linux/Documentation/userspace-api/ioctl/ioctl-number.rst (revision 6a143a7cf94730f57544ea14a987dc025364dbb8)
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.
32You can register the block by patching this file and submitting the
33patch to Linus Torvalds.  Or you can e-mail me at <mec@shout.net> and
34I'll register one for you.
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 user land for Linux/x86.  It contains
66most drivers up to 2.6.31, but I know I am missing some.  There has been
67no attempt to list non-X86 architectures or ioctls from drivers/staging/.
68
69====  =====  ======================================================= ================================================================
70Code  Seq#    Include File                                           Comments
71      (hex)
72====  =====  ======================================================= ================================================================
730x00  00-1F  linux/fs.h                                              conflict!
740x00  00-1F  scsi/scsi_ioctl.h                                       conflict!
750x00  00-1F  linux/fb.h                                              conflict!
760x00  00-1F  linux/wavefront.h                                       conflict!
770x02  all    linux/fd.h
780x03  all    linux/hdreg.h
790x04  D2-DC  linux/umsdos_fs.h                                       Dead since 2.6.11, but don't reuse these.
800x06  all    linux/lp.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
86             linux/blkpg.h
870x1b  all                                                            InfiniBand Subsystem
88                                                                     <http://infiniband.sourceforge.net/>
890x20  all    drivers/cdrom/cm206.h
900x22  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'H'   00-7F  linux/hiddev.h                                          conflict!
136'H'   00-0F  linux/hidraw.h                                          conflict!
137'H'   01     linux/mei.h                                             conflict!
138'H'   02     linux/mei.h                                             conflict!
139'H'   03     linux/mei.h                                             conflict!
140'H'   00-0F  sound/asound.h                                          conflict!
141'H'   20-40  sound/asound_fm.h                                       conflict!
142'H'   80-8F  sound/sfnt_info.h                                       conflict!
143'H'   10-8F  sound/emu10k1.h                                         conflict!
144'H'   10-1F  sound/sb16_csp.h                                        conflict!
145'H'   10-1F  sound/hda_hwdep.h                                       conflict!
146'H'   40-4F  sound/hdspm.h                                           conflict!
147'H'   40-4F  sound/hdsp.h                                            conflict!
148'H'   90     sound/usb/usx2y/usb_stream.h
149'H'   00-0F  uapi/misc/habanalabs.h                                  conflict!
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'K'   all    linux/kd.h
161'L'   00-1F  linux/loop.h                                            conflict!
162'L'   10-1F  drivers/scsi/mpt3sas/mpt3sas_ctl.h                      conflict!
163'L'   20-2F  linux/lightnvm.h
164'L'   E0-FF  linux/ppdd.h                                            encrypted disk device driver
165                                                                     <http://linux01.gwdg.de/~alatham/ppdd.html>
166'M'   all    linux/soundcard.h                                       conflict!
167'M'   01-16  mtd/mtd-abi.h                                           conflict!
168      and    drivers/mtd/mtdchar.c
169'M'   01-03  drivers/scsi/megaraid/megaraid_sas.h
170'M'   00-0F  drivers/video/fsl-diu-fb.h                              conflict!
171'N'   00-1F  drivers/usb/scanner.h
172'N'   40-7F  drivers/block/nvme.c
173'O'   00-06  mtd/ubi-user.h                                          UBI
174'P'   all    linux/soundcard.h                                       conflict!
175'P'   60-6F  sound/sscape_ioctl.h                                    conflict!
176'P'   00-0F  drivers/usb/class/usblp.c                               conflict!
177'P'   01-09  drivers/misc/pci_endpoint_test.c                        conflict!
178'Q'   all    linux/soundcard.h
179'R'   00-1F  linux/random.h                                          conflict!
180'R'   01     linux/rfkill.h                                          conflict!
181'R'   C0-DF  net/bluetooth/rfcomm.h
182'R'   E0     uapi/linux/fsl_mc.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'W'   60-61  linux/watch_queue.h
206'X'   all    fs/xfs/xfs_fs.h,                                        conflict!
207             fs/xfs/linux-2.6/xfs_ioctl32.h,
208             include/linux/falloc.h,
209             linux/fs.h,
210'X'   all    fs/ocfs2/ocfs_fs.h                                      conflict!
211'X'   01     linux/pktcdvd.h                                         conflict!
212'Y'   all    linux/cyclades.h
213'Z'   14-15  drivers/message/fusion/mptctl.h
214'['   00-3F  linux/usb/tmc.h                                         USB Test and Measurement Devices
215                                                                     <mailto:gregkh@linuxfoundation.org>
216'a'   all    linux/atm*.h, linux/sonet.h                             ATM on linux
217                                                                     <http://lrcwww.epfl.ch/>
218'a'   00-0F  drivers/crypto/qat/qat_common/adf_cfg_common.h          conflict! qat driver
219'b'   00-FF                                                          conflict! bit3 vme host bridge
220                                                                     <mailto:natalia@nikhefk.nikhef.nl>
221'c'   all    linux/cm4000_cs.h                                       conflict!
222'c'   00-7F  linux/comstats.h                                        conflict!
223'c'   00-7F  linux/coda.h                                            conflict!
224'c'   00-1F  linux/chio.h                                            conflict!
225'c'   80-9F  arch/s390/include/asm/chsc.h                            conflict!
226'c'   A0-AF  arch/x86/include/asm/msr.h conflict!
227'd'   00-FF  linux/char/drm/drm.h                                    conflict!
228'd'   02-40  pcmcia/ds.h                                             conflict!
229'd'   F0-FF  linux/digi1.h
230'e'   all    linux/digi1.h                                           conflict!
231'f'   00-1F  linux/ext2_fs.h                                         conflict!
232'f'   00-1F  linux/ext3_fs.h                                         conflict!
233'f'   00-0F  fs/jfs/jfs_dinode.h                                     conflict!
234'f'   00-0F  fs/ext4/ext4.h                                          conflict!
235'f'   00-0F  linux/fs.h                                              conflict!
236'f'   00-0F  fs/ocfs2/ocfs2_fs.h                                     conflict!
237'f'   13-27  linux/fscrypt.h
238'f'   81-8F  linux/fsverity.h
239'g'   00-0F  linux/usb/gadgetfs.h
240'g'   20-2F  linux/usb/g_printer.h
241'h'   00-7F                                                          conflict! Charon filesystem
242                                                                     <mailto:zapman@interlan.net>
243'h'   00-1F  linux/hpet.h                                            conflict!
244'h'   80-8F  fs/hfsplus/ioctl.c
245'i'   00-3F  linux/i2o-dev.h                                         conflict!
246'i'   0B-1F  linux/ipmi.h                                            conflict!
247'i'   80-8F  linux/i8k.h
248'j'   00-3F  linux/joystick.h
249'k'   00-0F  linux/spi/spidev.h                                      conflict!
250'k'   00-05  video/kyro.h                                            conflict!
251'k'   10-17  linux/hsi/hsi_char.h                                    HSI character device
252'l'   00-3F  linux/tcfs_fs.h                                         transparent cryptographic file system
253                                                                     <http://web.archive.org/web/%2A/http://mikonos.dia.unisa.it/tcfs>
254'l'   40-7F  linux/udf_fs_i.h                                        in development:
255                                                                     <http://sourceforge.net/projects/linux-udf/>
256'm'   00-09  linux/mmtimer.h                                         conflict!
257'm'   all    linux/mtio.h                                            conflict!
258'm'   all    linux/soundcard.h                                       conflict!
259'm'   all    linux/synclink.h                                        conflict!
260'm'   00-19  drivers/message/fusion/mptctl.h                         conflict!
261'm'   00     drivers/scsi/megaraid/megaraid_ioctl.h                  conflict!
262'n'   00-7F  linux/ncp_fs.h and fs/ncpfs/ioctl.c
263'n'   80-8F  uapi/linux/nilfs2_api.h                                 NILFS2
264'n'   E0-FF  linux/matroxfb.h                                        matroxfb
265'o'   00-1F  fs/ocfs2/ocfs2_fs.h                                     OCFS2
266'o'   00-03  mtd/ubi-user.h                                          conflict! (OCFS2 and UBI overlaps)
267'o'   40-41  mtd/ubi-user.h                                          UBI
268'o'   01-A1  `linux/dvb/*.h`                                         DVB
269'p'   00-0F  linux/phantom.h                                         conflict! (OpenHaptics needs this)
270'p'   00-1F  linux/rtc.h                                             conflict!
271'p'   40-7F  linux/nvram.h
272'p'   80-9F  linux/ppdev.h                                           user-space parport
273                                                                     <mailto:tim@cyberelk.net>
274'p'   A1-A5  linux/pps.h                                             LinuxPPS
275                                                                     <mailto:giometti@linux.it>
276'q'   00-1F  linux/serio.h
277'q'   80-FF  linux/telephony.h                                       Internet PhoneJACK, Internet LineJACK
278             linux/ixjuser.h                                         <http://web.archive.org/web/%2A/http://www.quicknet.net>
279'r'   00-1F  linux/msdos_fs.h and fs/fat/dir.c
280's'   all    linux/cdk.h
281't'   00-7F  linux/ppp-ioctl.h
282't'   80-8F  linux/isdn_ppp.h
283't'   90-91  linux/toshiba.h                                         toshiba and toshiba_acpi SMM
284'u'   00-1F  linux/smb_fs.h                                          gone
285'u'   20-3F  linux/uvcvideo.h                                        USB video class host driver
286'u'   40-4f  linux/udmabuf.h                                         userspace dma-buf misc device
287'v'   00-1F  linux/ext2_fs.h                                         conflict!
288'v'   00-1F  linux/fs.h                                              conflict!
289'v'   00-0F  linux/sonypi.h                                          conflict!
290'v'   00-0F  media/v4l2-subdev.h                                     conflict!
291'v'   20-27  arch/powerpc/include/uapi/asm/vas-api.h		     VAS API
292'v'   C0-FF  linux/meye.h                                            conflict!
293'w'   all                                                            CERN SCI driver
294'y'   00-1F                                                          packet based user level communications
295                                                                     <mailto:zapman@interlan.net>
296'z'   00-3F                                                          CAN bus card conflict!
297                                                                     <mailto:hdstich@connectu.ulm.circular.de>
298'z'   40-7F                                                          CAN bus card conflict!
299                                                                     <mailto:oe@port.de>
300'z'   10-4F  drivers/s390/crypto/zcrypt_api.h                        conflict!
301'|'   00-7F  linux/media.h
3020x80  00-1F  linux/fb.h
3030x89  00-06  arch/x86/include/asm/sockios.h
3040x89  0B-DF  linux/sockios.h
3050x89  E0-EF  linux/sockios.h                                         SIOCPROTOPRIVATE range
3060x89  E0-EF  linux/dn.h                                              PROTOPRIVATE range
3070x89  F0-FF  linux/sockios.h                                         SIOCDEVPRIVATE range
3080x8B  all    linux/wireless.h
3090x8C  00-3F                                                          WiNRADiO driver
310                                                                     <http://www.winradio.com.au/>
3110x90  00     drivers/cdrom/sbpcd.h
3120x92  00-0F  drivers/usb/mon/mon_bin.c
3130x93  60-7F  linux/auto_fs.h
3140x94  all    fs/btrfs/ioctl.h                                        Btrfs filesystem
315             and linux/fs.h                                          some lifted to vfs/generic
3160x97  00-7F  fs/ceph/ioctl.h                                         Ceph file system
3170x99  00-0F                                                          537-Addinboard driver
318                                                                     <mailto:buk@buks.ipn.de>
3190xA0  all    linux/sdp/sdp.h                                         Industrial Device Project
320                                                                     <mailto:kenji@bitgate.com>
3210xA1  0      linux/vtpm_proxy.h                                      TPM Emulator Proxy Driver
3220xA2  all    uapi/linux/acrn.h                                       ACRN hypervisor
3230xA3  80-8F                                                          Port ACL  in development:
324                                                                     <mailto:tlewis@mindspring.com>
3250xA3  90-9F  linux/dtlk.h
3260xA4  00-1F  uapi/linux/tee.h                                        Generic TEE subsystem
3270xA4  00-1F  uapi/asm/sgx.h                                          <mailto:linux-sgx@vger.kernel.org>
3280xA5  01     linux/surface_aggregator/cdev.h                         Microsoft Surface Platform System Aggregator
329                                                                     <mailto:luzmaximilian@gmail.com>
3300xAA  00-3F  linux/uapi/linux/userfaultfd.h
3310xAB  00-1F  linux/nbd.h
3320xAC  00-1F  linux/raw.h
3330xAD  00                                                             Netfilter device in development:
334                                                                     <mailto:rusty@rustcorp.com.au>
3350xAE  00-1F  linux/kvm.h                                             Kernel-based Virtual Machine
336                                                                     <mailto:kvm@vger.kernel.org>
3370xAE  40-FF  linux/kvm.h                                             Kernel-based Virtual Machine
338                                                                     <mailto:kvm@vger.kernel.org>
3390xAE  20-3F  linux/nitro_enclaves.h                                  Nitro Enclaves
3400xAF  00-1F  linux/fsl_hypervisor.h                                  Freescale hypervisor
3410xB0  all                                                            RATIO devices in development:
342                                                                     <mailto:vgo@ratio.de>
3430xB1  00-1F                                                          PPPoX
344                                                                     <mailto:mostrows@styx.uwaterloo.ca>
3450xB3  00     linux/mmc/ioctl.h
3460xB4  00-0F  linux/gpio.h                                            <mailto:linux-gpio@vger.kernel.org>
3470xB5  00-0F  uapi/linux/rpmsg.h                                      <mailto:linux-remoteproc@vger.kernel.org>
3480xB6  all    linux/fpga-dfl.h
3490xB7  all    uapi/linux/remoteproc_cdev.h                            <mailto:linux-remoteproc@vger.kernel.org>
3500xC0  00-0F  linux/usb/iowarrior.h
3510xCA  00-0F  uapi/misc/cxl.h
3520xCA  10-2F  uapi/misc/ocxl.h
3530xCA  80-BF  uapi/scsi/cxlflash_ioctl.h
3540xCB  00-1F                                                          CBM serial IEC bus in development:
355                                                                     <mailto:michael.klein@puffin.lb.shuttle.de>
3560xCC  00-0F  drivers/misc/ibmvmc.h                                   pseries VMC driver
3570xCD  01     linux/reiserfs_fs.h
3580xCE  01-02  uapi/linux/cxl_mem.h                                    Compute Express Link Memory Devices
3590xCF  02     fs/cifs/ioctl.c
3600xDB  00-0F  drivers/char/mwave/mwavepub.h
3610xDD  00-3F                                                          ZFCP device driver see drivers/s390/scsi/
362                                                                     <mailto:aherrman@de.ibm.com>
3630xE5  00-3F  linux/fuse.h
3640xEC  00-01  drivers/platform/chrome/cros_ec_dev.h                   ChromeOS EC driver
3650xF3  00-3F  drivers/usb/misc/sisusbvga/sisusb.h                     sisfb (in development)
366                                                                     <mailto:thomas@winischhofer.net>
3670xF6  all                                                            LTTng Linux Trace Toolkit Next Generation
368                                                                     <mailto:mathieu.desnoyers@efficios.com>
3690xFD  all    linux/dm-ioctl.h
3700xFE  all    linux/isst_if.h
371====  =====  ======================================================= ================================================================
372