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
85 0x12 all linux/fs.h BLK* ioctls
87 0x15 all linux/fs.h FS_IOC_* ioctls
88 0x1b all InfiniBand Subsystem
89 <http://infiniband.sourceforge.net/>
90 0x20 all drivers/cdrom/cm206.h
92 0x3E 00-0F linux/counter.h <mailto:linux-iio@vger.kernel.org>
93 '!' 00-1F uapi/linux/seccomp.h
94 '#' 00-3F IEEE 1394 Subsystem
95 Block for the entire subsystem
96 '$' 00-0F linux/perf_counter.h, linux/perf_event.h
97 '%' 00-0F include/uapi/linux/stm.h System Trace Module subsystem
98 <mailto:alexander.shishkin@linux.intel.com>
99 '&' 00-07 drivers/firewire/nosy-user.h
100 '1' 00-1F linux/timepps.h PPS kit from Ulrich Windl
101 <ftp://ftp.de.kernel.org/pub/linux/daemons/ntp/PPS/>
102 '2' 01-04 linux/i2o.h
103 '3' 00-0F drivers/s390/char/raw3270.h conflict!
104 '3' 00-1F linux/suspend_ioctls.h, conflict!
106 '8' all SNP8023 advanced NIC card
107 <mailto:mcr@solidum.com>
108 ';' 64-7F linux/vfio.h
109 ';' 80-FF linux/iommufd.h
110 '=' 00-3f uapi/linux/ptp_clock.h <mailto:richardcochran@gmail.com>
111 '@' 00-0F linux/radeonfb.h conflict!
112 '@' 00-0F drivers/video/aty/aty128fb.c conflict!
113 'A' 00-1F linux/apm_bios.h conflict!
114 'A' 00-0F linux/agpgart.h, conflict!
115 drivers/char/agp/compat_ioctl.h
116 'A' 00-7F sound/asound.h conflict!
117 'B' 00-1F linux/cciss_ioctl.h conflict!
118 'B' 00-0F include/linux/pmu.h conflict!
119 'B' C0-FF advanced bbus <mailto:maassen@uni-freiburg.de>
120 'B' 00-0F xen/xenbus_dev.h conflict!
121 'C' all linux/soundcard.h conflict!
122 'C' 01-2F linux/capi.h conflict!
123 'C' F0-FF drivers/net/wan/cosa.h conflict!
124 'D' all arch/s390/include/asm/dasd.h
125 'D' 40-5F drivers/scsi/dpt/dtpi_ioctl.h Dead since 2022
126 'D' 05 drivers/scsi/pmcraid.h
127 'E' all linux/input.h conflict!
128 'E' 00-0F xen/evtchn.h conflict!
129 'F' all linux/fb.h conflict!
130 'F' 01-02 drivers/scsi/pmcraid.h conflict!
131 'F' 20 drivers/video/fsl-diu-fb.h conflict!
132 'F' 20 linux/ivtvfb.h conflict!
133 'F' 20 linux/matroxfb.h conflict!
134 'F' 20 drivers/video/aty/atyfb_base.c conflict!
135 'F' 00-0F video/da8xx-fb.h conflict!
136 'F' 80-8F linux/arcfb.h conflict!
137 'F' DD video/sstfb.h conflict!
138 'G' 00-3F drivers/misc/sgi-gru/grulib.h conflict!
139 'G' 00-0F xen/gntalloc.h, xen/gntdev.h conflict!
140 'H' 00-7F linux/hiddev.h conflict!
141 'H' 00-0F linux/hidraw.h conflict!
142 'H' 01 linux/mei.h conflict!
143 'H' 02 linux/mei.h conflict!
144 'H' 03 linux/mei.h conflict!
145 'H' 00-0F sound/asound.h conflict!
146 'H' 20-40 sound/asound_fm.h conflict!
147 'H' 80-8F sound/sfnt_info.h conflict!
148 'H' 10-8F sound/emu10k1.h conflict!
149 'H' 10-1F sound/sb16_csp.h conflict!
150 'H' 10-1F sound/hda_hwdep.h conflict!
151 'H' 40-4F sound/hdspm.h conflict!
152 'H' 40-4F sound/hdsp.h conflict!
153 'H' 90 sound/usb/usx2y/usb_stream.h
154 'H' 00-0F uapi/misc/habanalabs.h conflict!
155 'H' A0 uapi/linux/usb/cdc-wdm.h
156 'H' C0-F0 net/bluetooth/hci.h conflict!
157 'H' C0-DF net/bluetooth/hidp/hidp.h conflict!
158 'H' C0-DF net/bluetooth/cmtp/cmtp.h conflict!
159 'H' C0-DF net/bluetooth/bnep/bnep.h conflict!
160 'H' F1 linux/hid-roccat.h <mailto:erazor_de@users.sourceforge.net>
161 'H' F8-FA sound/firewire.h
162 'I' all linux/isdn.h conflict!
163 'I' 00-0F drivers/isdn/divert/isdn_divert.h conflict!
164 'I' 40-4F linux/mISDNif.h conflict!
166 'L' 00-1F linux/loop.h conflict!
167 'L' 10-1F drivers/scsi/mpt3sas/mpt3sas_ctl.h conflict!
168 'L' E0-FF linux/ppdd.h encrypted disk device driver
169 <http://linux01.gwdg.de/~alatham/ppdd.html>
170 'M' all linux/soundcard.h conflict!
171 'M' 01-16 mtd/mtd-abi.h conflict!
172 and drivers/mtd/mtdchar.c
173 'M' 01-03 drivers/scsi/megaraid/megaraid_sas.h
174 'M' 00-0F drivers/video/fsl-diu-fb.h conflict!
175 'N' 00-1F drivers/usb/scanner.h
176 'N' 40-7F drivers/block/nvme.c
177 'O' 00-06 mtd/ubi-user.h UBI
178 'P' all linux/soundcard.h conflict!
179 'P' 60-6F sound/sscape_ioctl.h conflict!
180 'P' 00-0F drivers/usb/class/usblp.c conflict!
181 'P' 01-09 drivers/misc/pci_endpoint_test.c conflict!
182 'P' 00-0F xen/privcmd.h conflict!
183 'P' 00-05 linux/tps6594_pfsm.h conflict!
184 'Q' all linux/soundcard.h
185 'R' 00-1F linux/random.h conflict!
186 'R' 01 linux/rfkill.h conflict!
187 'R' C0-DF net/bluetooth/rfcomm.h
188 'R' E0 uapi/linux/fsl_mc.h
189 'S' all linux/cdrom.h conflict!
190 'S' 80-81 scsi/scsi_ioctl.h conflict!
191 'S' 82-FF scsi/scsi.h conflict!
192 'S' 00-7F sound/asequencer.h conflict!
193 'T' all linux/soundcard.h conflict!
194 'T' 00-AF sound/asound.h conflict!
195 'T' all arch/x86/include/asm/ioctls.h conflict!
196 'T' C0-DF linux/if_tun.h conflict!
197 'U' all sound/asound.h conflict!
198 'U' 00-CF linux/uinput.h conflict!
199 'U' 00-EF linux/usbdevice_fs.h
200 'U' C0-CF drivers/bluetooth/hci_uart.h
201 'V' all linux/vt.h conflict!
202 'V' all linux/videodev2.h conflict!
203 'V' C0 linux/ivtvfb.h conflict!
204 'V' C0 linux/ivtv.h conflict!
205 'V' C0 media/si4713.h conflict!
206 'W' 00-1F linux/watchdog.h conflict!
207 'W' 00-1F linux/wanrouter.h conflict! (pre 3.9)
208 'W' 00-3F sound/asound.h conflict!
209 'W' 40-5F drivers/pci/switch/switchtec.c
210 'W' 60-61 linux/watch_queue.h
211 'X' all fs/xfs/xfs_fs.h, conflict!
212 fs/xfs/linux-2.6/xfs_ioctl32.h,
213 include/linux/falloc.h,
215 'X' all fs/ocfs2/ocfs_fs.h conflict!
216 'X' 01 linux/pktcdvd.h conflict!
217 'Z' 14-15 drivers/message/fusion/mptctl.h
218 '[' 00-3F linux/usb/tmc.h USB Test and Measurement Devices
219 <mailto:gregkh@linuxfoundation.org>
220 'a' all linux/atm*.h, linux/sonet.h ATM on linux
221 <http://lrcwww.epfl.ch/>
222 'a' 00-0F drivers/crypto/qat/qat_common/adf_cfg_common.h conflict! qat driver
223 'b' 00-FF conflict! bit3 vme host bridge
224 <mailto:natalia@nikhefk.nikhef.nl>
225 'b' 00-0F linux/dma-buf.h conflict!
226 'c' 00-7F linux/comstats.h conflict!
227 'c' 00-7F linux/coda.h conflict!
228 'c' 00-1F linux/chio.h conflict!
229 'c' 80-9F arch/s390/include/asm/chsc.h conflict!
230 'c' A0-AF arch/x86/include/asm/msr.h conflict!
231 'd' 00-FF linux/char/drm/drm.h conflict!
232 'd' 02-40 pcmcia/ds.h conflict!
233 'd' F0-FF linux/digi1.h
234 'e' all linux/digi1.h conflict!
235 'f' 00-1F linux/ext2_fs.h conflict!
236 'f' 00-1F linux/ext3_fs.h conflict!
237 'f' 00-0F fs/jfs/jfs_dinode.h conflict!
238 'f' 00-0F fs/ext4/ext4.h conflict!
239 'f' 00-0F linux/fs.h conflict!
240 'f' 00-0F fs/ocfs2/ocfs2_fs.h conflict!
241 'f' 13-27 linux/fscrypt.h
242 'f' 81-8F linux/fsverity.h
243 'g' 00-0F linux/usb/gadgetfs.h
244 'g' 20-2F linux/usb/g_printer.h
245 'h' 00-7F conflict! Charon filesystem
246 <mailto:zapman@interlan.net>
247 'h' 00-1F linux/hpet.h conflict!
248 'h' 80-8F fs/hfsplus/ioctl.c
249 'i' 00-3F linux/i2o-dev.h conflict!
250 'i' 0B-1F linux/ipmi.h conflict!
251 'i' 80-8F linux/i8k.h
252 'i' 90-9F `linux/iio/*.h` IIO
253 'j' 00-3F linux/joystick.h
254 'k' 00-0F linux/spi/spidev.h conflict!
255 'k' 00-05 video/kyro.h conflict!
256 'k' 10-17 linux/hsi/hsi_char.h HSI character device
257 'l' 00-3F linux/tcfs_fs.h transparent cryptographic file system
258 <http://web.archive.org/web/%2A/http://mikonos.dia.unisa.it/tcfs>
259 'l' 40-7F linux/udf_fs_i.h in development:
260 <https://github.com/pali/udftools>
261 'm' 00-09 linux/mmtimer.h conflict!
262 'm' all linux/mtio.h conflict!
263 'm' all linux/soundcard.h conflict!
264 'm' all linux/synclink.h conflict!
265 'm' 00-19 drivers/message/fusion/mptctl.h conflict!
266 'm' 00 drivers/scsi/megaraid/megaraid_ioctl.h conflict!
267 'n' 00-7F linux/ncp_fs.h and fs/ncpfs/ioctl.c
268 'n' 80-8F uapi/linux/nilfs2_api.h NILFS2
269 'n' E0-FF linux/matroxfb.h matroxfb
270 'o' 00-1F fs/ocfs2/ocfs2_fs.h OCFS2
271 'o' 00-03 mtd/ubi-user.h conflict! (OCFS2 and UBI overlaps)
272 'o' 40-41 mtd/ubi-user.h UBI
273 'o' 01-A1 `linux/dvb/*.h` DVB
274 'p' 00-0F linux/phantom.h conflict! (OpenHaptics needs this)
275 'p' 00-1F linux/rtc.h conflict!
276 'p' 40-7F linux/nvram.h
277 'p' 80-9F linux/ppdev.h user-space parport
278 <mailto:tim@cyberelk.net>
279 'p' A1-A5 linux/pps.h LinuxPPS
280 <mailto:giometti@linux.it>
281 'q' 00-1F linux/serio.h
282 'q' 80-FF linux/telephony.h Internet PhoneJACK, Internet LineJACK
283 linux/ixjuser.h <http://web.archive.org/web/%2A/http://www.quicknet.net>
284 'r' 00-1F linux/msdos_fs.h and fs/fat/dir.c
286 't' 00-7F linux/ppp-ioctl.h
287 't' 80-8F linux/isdn_ppp.h
288 't' 90-91 linux/toshiba.h toshiba and toshiba_acpi SMM
289 'u' 00-1F linux/smb_fs.h gone
290 'u' 20-3F linux/uvcvideo.h USB video class host driver
291 'u' 40-4f linux/udmabuf.h userspace dma-buf misc device
292 'v' 00-1F linux/ext2_fs.h conflict!
293 'v' 00-1F linux/fs.h conflict!
294 'v' 00-0F linux/sonypi.h conflict!
295 'v' 00-0F media/v4l2-subdev.h conflict!
296 'v' 20-27 arch/powerpc/include/uapi/asm/vas-api.h VAS API
297 'v' C0-FF linux/meye.h conflict!
298 'w' all CERN SCI driver
299 'y' 00-1F packet based user level communications
300 <mailto:zapman@interlan.net>
301 'z' 00-3F CAN bus card conflict!
302 <mailto:hdstich@connectu.ulm.circular.de>
303 'z' 40-7F CAN bus card conflict!
305 'z' 10-4F drivers/s390/crypto/zcrypt_api.h conflict!
306 '|' 00-7F linux/media.h
307 0x80 00-1F linux/fb.h
308 0x81 00-1F linux/vduse.h
309 0x89 00-06 arch/x86/include/asm/sockios.h
310 0x89 0B-DF linux/sockios.h
311 0x89 E0-EF linux/sockios.h SIOCPROTOPRIVATE range
312 0x89 F0-FF linux/sockios.h SIOCDEVPRIVATE range
313 0x8A 00-1F linux/eventpoll.h
314 0x8B all linux/wireless.h
315 0x8C 00-3F WiNRADiO driver
316 <http://www.winradio.com.au/>
317 0x90 00 drivers/cdrom/sbpcd.h
318 0x92 00-0F drivers/usb/mon/mon_bin.c
319 0x93 60-7F linux/auto_fs.h
320 0x94 all fs/btrfs/ioctl.h Btrfs filesystem
321 and linux/fs.h some lifted to vfs/generic
322 0x97 00-7F fs/ceph/ioctl.h Ceph file system
323 0x99 00-0F 537-Addinboard driver
324 <mailto:buk@buks.ipn.de>
325 0xA0 all linux/sdp/sdp.h Industrial Device Project
326 <mailto:kenji@bitgate.com>
327 0xA1 0 linux/vtpm_proxy.h TPM Emulator Proxy Driver
328 0xA2 all uapi/linux/acrn.h ACRN hypervisor
329 0xA3 80-8F Port ACL in development:
330 <mailto:tlewis@mindspring.com>
331 0xA3 90-9F linux/dtlk.h
332 0xA4 00-1F uapi/linux/tee.h Generic TEE subsystem
333 0xA4 00-1F uapi/asm/sgx.h <mailto:linux-sgx@vger.kernel.org>
334 0xA5 01-05 linux/surface_aggregator/cdev.h Microsoft Surface Platform System Aggregator
335 <mailto:luzmaximilian@gmail.com>
336 0xA5 20-2F linux/surface_aggregator/dtx.h Microsoft Surface DTX driver
337 <mailto:luzmaximilian@gmail.com>
338 0xAA 00-3F linux/uapi/linux/userfaultfd.h
339 0xAB 00-1F linux/nbd.h
340 0xAC 00-1F linux/raw.h
341 0xAD 00 Netfilter device in development:
342 <mailto:rusty@rustcorp.com.au>
343 0xAE 00-1F linux/kvm.h Kernel-based Virtual Machine
344 <mailto:kvm@vger.kernel.org>
345 0xAE 40-FF linux/kvm.h Kernel-based Virtual Machine
346 <mailto:kvm@vger.kernel.org>
347 0xAE 20-3F linux/nitro_enclaves.h Nitro Enclaves
348 0xAF 00-1F linux/fsl_hypervisor.h Freescale hypervisor
349 0xB0 all RATIO devices in development:
350 <mailto:vgo@ratio.de>
352 <mailto:mostrows@styx.uwaterloo.ca>
353 0xB2 00 arch/powerpc/include/uapi/asm/papr-vpd.h powerpc/pseries VPD API
354 <mailto:linuxppc-dev>
355 0xB2 01-02 arch/powerpc/include/uapi/asm/papr-sysparm.h powerpc/pseries system parameter API
356 <mailto:linuxppc-dev>
357 0xB3 00 linux/mmc/ioctl.h
358 0xB4 00-0F linux/gpio.h <mailto:linux-gpio@vger.kernel.org>
359 0xB5 00-0F uapi/linux/rpmsg.h <mailto:linux-remoteproc@vger.kernel.org>
360 0xB6 all linux/fpga-dfl.h
361 0xB7 all uapi/linux/remoteproc_cdev.h <mailto:linux-remoteproc@vger.kernel.org>
362 0xB7 all uapi/linux/nsfs.h <mailto:Andrei Vagin <avagin@openvz.org>>
363 0xC0 00-0F linux/usb/iowarrior.h
364 0xCA 00-0F uapi/misc/cxl.h
365 0xCA 10-2F uapi/misc/ocxl.h
366 0xCA 80-BF uapi/scsi/cxlflash_ioctl.h
367 0xCB 00-1F CBM serial IEC bus in development:
368 <mailto:michael.klein@puffin.lb.shuttle.de>
369 0xCC 00-0F drivers/misc/ibmvmc.h pseries VMC driver
370 0xCD 01 linux/reiserfs_fs.h
371 0xCE 01-02 uapi/linux/cxl_mem.h Compute Express Link Memory Devices
372 0xCF 02 fs/smb/client/cifs_ioctl.h
373 0xDB 00-0F drivers/char/mwave/mwavepub.h
374 0xDD 00-3F ZFCP device driver see drivers/s390/scsi/
375 <mailto:aherrman@de.ibm.com>
376 0xE5 00-3F linux/fuse.h
377 0xEC 00-01 drivers/platform/chrome/cros_ec_dev.h ChromeOS EC driver
378 0xEE 00-09 uapi/linux/pfrut.h Platform Firmware Runtime Update and Telemetry
379 0xF3 00-3F drivers/usb/misc/sisusbvga/sisusb.h sisfb (in development)
380 <mailto:thomas@winischhofer.net>
381 0xF6 all LTTng Linux Trace Toolkit Next Generation
382 <mailto:mathieu.desnoyers@efficios.com>
383 0xF8 all arch/x86/include/uapi/asm/amd_hsmp.h AMD HSMP EPYC system management interface driver
384 <mailto:nchatrad@amd.com>
385 0xFD all linux/dm-ioctl.h
386 0xFE all linux/isst_if.h
387 ==== ===== ======================================================= ================================================================