7 Michael Elizabeth Chastain
10 If you are adding new ioctl's to the kernel, you should use the _IO
11 macros defined in <linux/ioctl.h>:
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 ====== == ============================================
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
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.
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.
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.
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
47 Following this convention is good because:
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.
53 (2) The 'strace' build procedure automatically finds ioctl numbers
54 defined with _IO, _IOW, _IOR, or _IOWR.
56 (3) 'strace' can decode numbers back into useful names when the
59 (4) People looking for ioctls can grep for them more easily when
60 this convention is used to define the ioctl numbers.
62 (5) When following the convention, the driver code can use generic
63 code to copy the parameters between user and kernel space.
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/.
69 ==== ===== ======================================================= ================================================================
70 Code Seq# Include File Comments
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!
78 0x03 all linux/hdreg.h
79 0x04 D2-DC linux/umsdos_fs.h Dead since 2.6.11, but don't reuse these.
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
87 0x1b all InfiniBand Subsystem
88 <http://infiniband.sourceforge.net/>
89 0x20 all drivers/cdrom/cm206.h
91 0x3E 00-0F linux/counter.h <mailto:linux-iio@vger.kernel.org>
92 '!' 00-1F uapi/linux/seccomp.h
93 '#' 00-3F IEEE 1394 Subsystem
94 Block for the entire subsystem
95 '$' 00-0F linux/perf_counter.h, linux/perf_event.h
96 '%' 00-0F include/uapi/linux/stm.h System Trace Module subsystem
97 <mailto:alexander.shishkin@linux.intel.com>
98 '&' 00-07 drivers/firewire/nosy-user.h
99 '1' 00-1F linux/timepps.h PPS kit from Ulrich Windl
100 <ftp://ftp.de.kernel.org/pub/linux/daemons/ntp/PPS/>
101 '2' 01-04 linux/i2o.h
102 '3' 00-0F drivers/s390/char/raw3270.h conflict!
103 '3' 00-1F linux/suspend_ioctls.h, conflict!
105 '8' all SNP8023 advanced NIC card
106 <mailto:mcr@solidum.com>
107 ';' 64-7F linux/vfio.h
108 '=' 00-3f uapi/linux/ptp_clock.h <mailto:richardcochran@gmail.com>
109 '@' 00-0F linux/radeonfb.h conflict!
110 '@' 00-0F drivers/video/aty/aty128fb.c conflict!
111 'A' 00-1F linux/apm_bios.h conflict!
112 'A' 00-0F linux/agpgart.h, conflict!
113 drivers/char/agp/compat_ioctl.h
114 'A' 00-7F sound/asound.h conflict!
115 'B' 00-1F linux/cciss_ioctl.h conflict!
116 'B' 00-0F include/linux/pmu.h conflict!
117 'B' C0-FF advanced bbus <mailto:maassen@uni-freiburg.de>
118 'B' 00-0F xen/xenbus_dev.h conflict!
119 'C' all linux/soundcard.h conflict!
120 'C' 01-2F linux/capi.h conflict!
121 'C' F0-FF drivers/net/wan/cosa.h conflict!
122 'D' all arch/s390/include/asm/dasd.h
123 'D' 40-5F drivers/scsi/dpt/dtpi_ioctl.h Dead since 2022
124 'D' 05 drivers/scsi/pmcraid.h
125 'E' all linux/input.h conflict!
126 'E' 00-0F xen/evtchn.h conflict!
127 'F' all linux/fb.h conflict!
128 'F' 01-02 drivers/scsi/pmcraid.h conflict!
129 'F' 20 drivers/video/fsl-diu-fb.h conflict!
130 'F' 20 drivers/video/intelfb/intelfb.h conflict!
131 'F' 20 linux/ivtvfb.h conflict!
132 'F' 20 linux/matroxfb.h conflict!
133 'F' 20 drivers/video/aty/atyfb_base.c conflict!
134 'F' 00-0F video/da8xx-fb.h conflict!
135 'F' 80-8F linux/arcfb.h conflict!
136 'F' DD video/sstfb.h conflict!
137 'G' 00-3F drivers/misc/sgi-gru/grulib.h conflict!
138 'G' 00-0F xen/gntalloc.h, xen/gntdev.h conflict!
139 'H' 00-7F linux/hiddev.h conflict!
140 'H' 00-0F linux/hidraw.h conflict!
141 'H' 01 linux/mei.h conflict!
142 'H' 02 linux/mei.h conflict!
143 'H' 03 linux/mei.h conflict!
144 'H' 00-0F sound/asound.h conflict!
145 'H' 20-40 sound/asound_fm.h conflict!
146 'H' 80-8F sound/sfnt_info.h conflict!
147 'H' 10-8F sound/emu10k1.h conflict!
148 'H' 10-1F sound/sb16_csp.h conflict!
149 'H' 10-1F sound/hda_hwdep.h conflict!
150 'H' 40-4F sound/hdspm.h conflict!
151 'H' 40-4F sound/hdsp.h conflict!
152 'H' 90 sound/usb/usx2y/usb_stream.h
153 'H' 00-0F uapi/misc/habanalabs.h conflict!
154 'H' A0 uapi/linux/usb/cdc-wdm.h
155 'H' C0-F0 net/bluetooth/hci.h conflict!
156 'H' C0-DF net/bluetooth/hidp/hidp.h conflict!
157 'H' C0-DF net/bluetooth/cmtp/cmtp.h conflict!
158 'H' C0-DF net/bluetooth/bnep/bnep.h conflict!
159 'H' F1 linux/hid-roccat.h <mailto:erazor_de@users.sourceforge.net>
160 'H' F8-FA sound/firewire.h
161 'I' all linux/isdn.h conflict!
162 'I' 00-0F drivers/isdn/divert/isdn_divert.h conflict!
163 'I' 40-4F linux/mISDNif.h conflict!
165 'L' 00-1F linux/loop.h conflict!
166 'L' 10-1F drivers/scsi/mpt3sas/mpt3sas_ctl.h conflict!
167 'L' E0-FF linux/ppdd.h encrypted disk device driver
168 <http://linux01.gwdg.de/~alatham/ppdd.html>
169 'M' all linux/soundcard.h conflict!
170 'M' 01-16 mtd/mtd-abi.h conflict!
171 and drivers/mtd/mtdchar.c
172 'M' 01-03 drivers/scsi/megaraid/megaraid_sas.h
173 'M' 00-0F drivers/video/fsl-diu-fb.h conflict!
174 'N' 00-1F drivers/usb/scanner.h
175 'N' 40-7F drivers/block/nvme.c
176 'O' 00-06 mtd/ubi-user.h UBI
177 'P' all linux/soundcard.h conflict!
178 'P' 60-6F sound/sscape_ioctl.h conflict!
179 'P' 00-0F drivers/usb/class/usblp.c conflict!
180 'P' 01-09 drivers/misc/pci_endpoint_test.c conflict!
181 'P' 00-0F xen/privcmd.h conflict!
182 'Q' all linux/soundcard.h
183 'R' 00-1F linux/random.h conflict!
184 'R' 01 linux/rfkill.h conflict!
185 'R' C0-DF net/bluetooth/rfcomm.h
186 'R' E0 uapi/linux/fsl_mc.h
187 'S' all linux/cdrom.h conflict!
188 'S' 80-81 scsi/scsi_ioctl.h conflict!
189 'S' 82-FF scsi/scsi.h conflict!
190 'S' 00-7F sound/asequencer.h conflict!
191 'T' all linux/soundcard.h conflict!
192 'T' 00-AF sound/asound.h conflict!
193 'T' all arch/x86/include/asm/ioctls.h conflict!
194 'T' C0-DF linux/if_tun.h conflict!
195 'U' all sound/asound.h conflict!
196 'U' 00-CF linux/uinput.h conflict!
197 'U' 00-EF linux/usbdevice_fs.h
198 'U' C0-CF drivers/bluetooth/hci_uart.h
199 'V' all linux/vt.h conflict!
200 'V' all linux/videodev2.h conflict!
201 'V' C0 linux/ivtvfb.h conflict!
202 'V' C0 linux/ivtv.h conflict!
203 'V' C0 media/davinci/vpfe_capture.h conflict!
204 'V' C0 media/si4713.h conflict!
205 'W' 00-1F linux/watchdog.h conflict!
206 'W' 00-1F linux/wanrouter.h conflict! (pre 3.9)
207 'W' 00-3F sound/asound.h conflict!
208 'W' 40-5F drivers/pci/switch/switchtec.c
209 'W' 60-61 linux/watch_queue.h
210 'X' all fs/xfs/xfs_fs.h, conflict!
211 fs/xfs/linux-2.6/xfs_ioctl32.h,
212 include/linux/falloc.h,
214 'X' all fs/ocfs2/ocfs_fs.h conflict!
215 'X' 01 linux/pktcdvd.h conflict!
216 'Z' 14-15 drivers/message/fusion/mptctl.h
217 '[' 00-3F linux/usb/tmc.h USB Test and Measurement Devices
218 <mailto:gregkh@linuxfoundation.org>
219 'a' all linux/atm*.h, linux/sonet.h ATM on linux
220 <http://lrcwww.epfl.ch/>
221 'a' 00-0F drivers/crypto/qat/qat_common/adf_cfg_common.h conflict! qat driver
222 'b' 00-FF conflict! bit3 vme host bridge
223 <mailto:natalia@nikhefk.nikhef.nl>
224 'c' all linux/cm4000_cs.h conflict!
225 'c' 00-7F linux/comstats.h conflict!
226 'c' 00-7F linux/coda.h conflict!
227 'c' 00-1F linux/chio.h conflict!
228 'c' 80-9F arch/s390/include/asm/chsc.h conflict!
229 'c' A0-AF arch/x86/include/asm/msr.h conflict!
230 'd' 00-FF linux/char/drm/drm.h conflict!
231 'd' 02-40 pcmcia/ds.h conflict!
232 'd' F0-FF linux/digi1.h
233 'e' all linux/digi1.h conflict!
234 'f' 00-1F linux/ext2_fs.h conflict!
235 'f' 00-1F linux/ext3_fs.h conflict!
236 'f' 00-0F fs/jfs/jfs_dinode.h conflict!
237 'f' 00-0F fs/ext4/ext4.h conflict!
238 'f' 00-0F linux/fs.h conflict!
239 'f' 00-0F fs/ocfs2/ocfs2_fs.h conflict!
240 'f' 13-27 linux/fscrypt.h
241 'f' 81-8F linux/fsverity.h
242 'g' 00-0F linux/usb/gadgetfs.h
243 'g' 20-2F linux/usb/g_printer.h
244 'h' 00-7F conflict! Charon filesystem
245 <mailto:zapman@interlan.net>
246 'h' 00-1F linux/hpet.h conflict!
247 'h' 80-8F fs/hfsplus/ioctl.c
248 'i' 00-3F linux/i2o-dev.h conflict!
249 'i' 0B-1F linux/ipmi.h conflict!
250 'i' 80-8F linux/i8k.h
251 'i' 90-9F `linux/iio/*.h` IIO
252 'j' 00-3F linux/joystick.h
253 'k' 00-0F linux/spi/spidev.h conflict!
254 'k' 00-05 video/kyro.h conflict!
255 'k' 10-17 linux/hsi/hsi_char.h HSI character device
256 'l' 00-3F linux/tcfs_fs.h transparent cryptographic file system
257 <http://web.archive.org/web/%2A/http://mikonos.dia.unisa.it/tcfs>
258 'l' 40-7F linux/udf_fs_i.h in development:
259 <https://github.com/pali/udftools>
260 'm' 00-09 linux/mmtimer.h conflict!
261 'm' all linux/mtio.h conflict!
262 'm' all linux/soundcard.h conflict!
263 'm' all linux/synclink.h conflict!
264 'm' 00-19 drivers/message/fusion/mptctl.h conflict!
265 'm' 00 drivers/scsi/megaraid/megaraid_ioctl.h conflict!
266 'n' 00-7F linux/ncp_fs.h and fs/ncpfs/ioctl.c
267 'n' 80-8F uapi/linux/nilfs2_api.h NILFS2
268 'n' E0-FF linux/matroxfb.h matroxfb
269 'o' 00-1F fs/ocfs2/ocfs2_fs.h OCFS2
270 'o' 00-03 mtd/ubi-user.h conflict! (OCFS2 and UBI overlaps)
271 'o' 40-41 mtd/ubi-user.h UBI
272 'o' 01-A1 `linux/dvb/*.h` DVB
273 'p' 00-0F linux/phantom.h conflict! (OpenHaptics needs this)
274 'p' 00-1F linux/rtc.h conflict!
275 'p' 40-7F linux/nvram.h
276 'p' 80-9F linux/ppdev.h user-space parport
277 <mailto:tim@cyberelk.net>
278 'p' A1-A5 linux/pps.h LinuxPPS
279 <mailto:giometti@linux.it>
280 'q' 00-1F linux/serio.h
281 'q' 80-FF linux/telephony.h Internet PhoneJACK, Internet LineJACK
282 linux/ixjuser.h <http://web.archive.org/web/%2A/http://www.quicknet.net>
283 'r' 00-1F linux/msdos_fs.h and fs/fat/dir.c
285 't' 00-7F linux/ppp-ioctl.h
286 't' 80-8F linux/isdn_ppp.h
287 't' 90-91 linux/toshiba.h toshiba and toshiba_acpi SMM
288 'u' 00-1F linux/smb_fs.h gone
289 'u' 20-3F linux/uvcvideo.h USB video class host driver
290 'u' 40-4f linux/udmabuf.h userspace dma-buf misc device
291 'v' 00-1F linux/ext2_fs.h conflict!
292 'v' 00-1F linux/fs.h conflict!
293 'v' 00-0F linux/sonypi.h conflict!
294 'v' 00-0F media/v4l2-subdev.h conflict!
295 'v' 20-27 arch/powerpc/include/uapi/asm/vas-api.h VAS API
296 'v' C0-FF linux/meye.h conflict!
297 'w' all CERN SCI driver
298 'y' 00-1F packet based user level communications
299 <mailto:zapman@interlan.net>
300 'z' 00-3F CAN bus card conflict!
301 <mailto:hdstich@connectu.ulm.circular.de>
302 'z' 40-7F CAN bus card conflict!
304 'z' 10-4F drivers/s390/crypto/zcrypt_api.h conflict!
305 '|' 00-7F linux/media.h
306 0x80 00-1F linux/fb.h
307 0x81 00-1F linux/vduse.h
308 0x89 00-06 arch/x86/include/asm/sockios.h
309 0x89 0B-DF linux/sockios.h
310 0x89 E0-EF linux/sockios.h SIOCPROTOPRIVATE range
311 0x89 F0-FF linux/sockios.h SIOCDEVPRIVATE range
312 0x8B all linux/wireless.h
313 0x8C 00-3F WiNRADiO driver
314 <http://www.winradio.com.au/>
315 0x90 00 drivers/cdrom/sbpcd.h
316 0x92 00-0F drivers/usb/mon/mon_bin.c
317 0x93 60-7F linux/auto_fs.h
318 0x94 all fs/btrfs/ioctl.h Btrfs filesystem
319 and linux/fs.h some lifted to vfs/generic
320 0x97 00-7F fs/ceph/ioctl.h Ceph file system
321 0x99 00-0F 537-Addinboard driver
322 <mailto:buk@buks.ipn.de>
323 0xA0 all linux/sdp/sdp.h Industrial Device Project
324 <mailto:kenji@bitgate.com>
325 0xA1 0 linux/vtpm_proxy.h TPM Emulator Proxy Driver
326 0xA2 all uapi/linux/acrn.h ACRN hypervisor
327 0xA3 80-8F Port ACL in development:
328 <mailto:tlewis@mindspring.com>
329 0xA3 90-9F linux/dtlk.h
330 0xA4 00-1F uapi/linux/tee.h Generic TEE subsystem
331 0xA4 00-1F uapi/asm/sgx.h <mailto:linux-sgx@vger.kernel.org>
332 0xA5 01-05 linux/surface_aggregator/cdev.h Microsoft Surface Platform System Aggregator
333 <mailto:luzmaximilian@gmail.com>
334 0xA5 20-2F linux/surface_aggregator/dtx.h Microsoft Surface DTX driver
335 <mailto:luzmaximilian@gmail.com>
336 0xAA 00-3F linux/uapi/linux/userfaultfd.h
337 0xAB 00-1F linux/nbd.h
338 0xAC 00-1F linux/raw.h
339 0xAD 00 Netfilter device in development:
340 <mailto:rusty@rustcorp.com.au>
341 0xAE 00-1F linux/kvm.h Kernel-based Virtual Machine
342 <mailto:kvm@vger.kernel.org>
343 0xAE 40-FF linux/kvm.h Kernel-based Virtual Machine
344 <mailto:kvm@vger.kernel.org>
345 0xAE 20-3F linux/nitro_enclaves.h Nitro Enclaves
346 0xAF 00-1F linux/fsl_hypervisor.h Freescale hypervisor
347 0xB0 all RATIO devices in development:
348 <mailto:vgo@ratio.de>
350 <mailto:mostrows@styx.uwaterloo.ca>
351 0xB3 00 linux/mmc/ioctl.h
352 0xB4 00-0F linux/gpio.h <mailto:linux-gpio@vger.kernel.org>
353 0xB5 00-0F uapi/linux/rpmsg.h <mailto:linux-remoteproc@vger.kernel.org>
354 0xB6 all linux/fpga-dfl.h
355 0xB7 all uapi/linux/remoteproc_cdev.h <mailto:linux-remoteproc@vger.kernel.org>
356 0xB7 all uapi/linux/nsfs.h <mailto:Andrei Vagin <avagin@openvz.org>>
357 0xC0 00-0F linux/usb/iowarrior.h
358 0xCA 00-0F uapi/misc/cxl.h
359 0xCA 10-2F uapi/misc/ocxl.h
360 0xCA 80-BF uapi/scsi/cxlflash_ioctl.h
361 0xCB 00-1F CBM serial IEC bus in development:
362 <mailto:michael.klein@puffin.lb.shuttle.de>
363 0xCC 00-0F drivers/misc/ibmvmc.h pseries VMC driver
364 0xCD 01 linux/reiserfs_fs.h
365 0xCE 01-02 uapi/linux/cxl_mem.h Compute Express Link Memory Devices
366 0xCF 02 fs/cifs/ioctl.c
367 0xDB 00-0F drivers/char/mwave/mwavepub.h
368 0xDD 00-3F ZFCP device driver see drivers/s390/scsi/
369 <mailto:aherrman@de.ibm.com>
370 0xE5 00-3F linux/fuse.h
371 0xEC 00-01 drivers/platform/chrome/cros_ec_dev.h ChromeOS EC driver
372 0xEE 00-09 uapi/linux/pfrut.h Platform Firmware Runtime Update and Telemetry
373 0xF3 00-3F drivers/usb/misc/sisusbvga/sisusb.h sisfb (in development)
374 <mailto:thomas@winischhofer.net>
375 0xF6 all LTTng Linux Trace Toolkit Next Generation
376 <mailto:mathieu.desnoyers@efficios.com>
377 0xF8 all arch/x86/include/uapi/asm/amd_hsmp.h AMD HSMP EPYC system management interface driver
378 <mailto:nchatrad@amd.com>
379 0xFD all linux/dm-ioctl.h
380 0xFE all linux/isst_if.h
381 ==== ===== ======================================================= ================================================================