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 '!' 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!
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!
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,
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
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!
300 'z' 10-4F drivers/s390/crypto/zcrypt_api.h conflict!
301 '|' 00-7F linux/media.h
302 0x80 00-1F linux/fb.h
303 0x89 00-06 arch/x86/include/asm/sockios.h
304 0x89 0B-DF linux/sockios.h
305 0x89 E0-EF linux/sockios.h SIOCPROTOPRIVATE range
306 0x89 E0-EF linux/dn.h PROTOPRIVATE range
307 0x89 F0-FF linux/sockios.h SIOCDEVPRIVATE range
308 0x8B all linux/wireless.h
309 0x8C 00-3F WiNRADiO driver
310 <http://www.winradio.com.au/>
311 0x90 00 drivers/cdrom/sbpcd.h
312 0x92 00-0F drivers/usb/mon/mon_bin.c
313 0x93 60-7F linux/auto_fs.h
314 0x94 all fs/btrfs/ioctl.h Btrfs filesystem
315 and linux/fs.h some lifted to vfs/generic
316 0x97 00-7F fs/ceph/ioctl.h Ceph file system
317 0x99 00-0F 537-Addinboard driver
318 <mailto:buk@buks.ipn.de>
319 0xA0 all linux/sdp/sdp.h Industrial Device Project
320 <mailto:kenji@bitgate.com>
321 0xA1 0 linux/vtpm_proxy.h TPM Emulator Proxy Driver
322 0xA2 all uapi/linux/acrn.h ACRN hypervisor
323 0xA3 80-8F Port ACL in development:
324 <mailto:tlewis@mindspring.com>
325 0xA3 90-9F linux/dtlk.h
326 0xA4 00-1F uapi/linux/tee.h Generic TEE subsystem
327 0xA4 00-1F uapi/asm/sgx.h <mailto:linux-sgx@vger.kernel.org>
328 0xA5 01 linux/surface_aggregator/cdev.h Microsoft Surface Platform System Aggregator
329 <mailto:luzmaximilian@gmail.com>
330 0xAA 00-3F linux/uapi/linux/userfaultfd.h
331 0xAB 00-1F linux/nbd.h
332 0xAC 00-1F linux/raw.h
333 0xAD 00 Netfilter device in development:
334 <mailto:rusty@rustcorp.com.au>
335 0xAE 00-1F linux/kvm.h Kernel-based Virtual Machine
336 <mailto:kvm@vger.kernel.org>
337 0xAE 40-FF linux/kvm.h Kernel-based Virtual Machine
338 <mailto:kvm@vger.kernel.org>
339 0xAE 20-3F linux/nitro_enclaves.h Nitro Enclaves
340 0xAF 00-1F linux/fsl_hypervisor.h Freescale hypervisor
341 0xB0 all RATIO devices in development:
342 <mailto:vgo@ratio.de>
344 <mailto:mostrows@styx.uwaterloo.ca>
345 0xB3 00 linux/mmc/ioctl.h
346 0xB4 00-0F linux/gpio.h <mailto:linux-gpio@vger.kernel.org>
347 0xB5 00-0F uapi/linux/rpmsg.h <mailto:linux-remoteproc@vger.kernel.org>
348 0xB6 all linux/fpga-dfl.h
349 0xB7 all uapi/linux/remoteproc_cdev.h <mailto:linux-remoteproc@vger.kernel.org>
350 0xC0 00-0F linux/usb/iowarrior.h
351 0xCA 00-0F uapi/misc/cxl.h
352 0xCA 10-2F uapi/misc/ocxl.h
353 0xCA 80-BF uapi/scsi/cxlflash_ioctl.h
354 0xCB 00-1F CBM serial IEC bus in development:
355 <mailto:michael.klein@puffin.lb.shuttle.de>
356 0xCC 00-0F drivers/misc/ibmvmc.h pseries VMC driver
357 0xCD 01 linux/reiserfs_fs.h
358 0xCE 01-02 uapi/linux/cxl_mem.h Compute Express Link Memory Devices
359 0xCF 02 fs/cifs/ioctl.c
360 0xDB 00-0F drivers/char/mwave/mwavepub.h
361 0xDD 00-3F ZFCP device driver see drivers/s390/scsi/
362 <mailto:aherrman@de.ibm.com>
363 0xE5 00-3F linux/fuse.h
364 0xEC 00-01 drivers/platform/chrome/cros_ec_dev.h ChromeOS EC driver
365 0xF3 00-3F drivers/usb/misc/sisusbvga/sisusb.h sisfb (in development)
366 <mailto:thomas@winischhofer.net>
367 0xF6 all LTTng Linux Trace Toolkit Next Generation
368 <mailto:mathieu.desnoyers@efficios.com>
369 0xFD all linux/dm-ioctl.h
370 0xFE all linux/isst_if.h
371 ==== ===== ======================================================= ================================================================