3 Michael Elizabeth Chastain
6 If you are adding new ioctl's to the kernel, you should use the _IO
7 macros defined in <linux/ioctl.h>:
9 _IO an ioctl with no parameters
10 _IOW an ioctl with write parameters (copy_from_user)
11 _IOR an ioctl with read parameters (copy_to_user)
12 _IOWR an ioctl with both write and read parameters.
14 'Write' and 'read' are from the user's point of view, just like the
15 system calls 'write' and 'read'. For example, a SET_FOO ioctl would
16 be _IOW, although the kernel would actually read data from user space;
17 a GET_FOO ioctl would be _IOR, although the kernel would actually write
20 The first argument to _IO, _IOW, _IOR, or _IOWR is an identifying letter
21 or number from the table below. Because of the large number of drivers,
22 many drivers share a partial letter with other drivers.
24 If you are writing a driver for a new device and need a letter, pick an
25 unused block with enough room for expansion: 32 to 256 ioctl commands.
26 You can register the block by patching this file and submitting the
27 patch to Linus Torvalds. Or you can e-mail me at <mec@shout.net> and
28 I'll register one for you.
30 The second argument to _IO, _IOW, _IOR, or _IOWR is a sequence number
31 to distinguish ioctls from each other. The third argument to _IOW,
32 _IOR, or _IOWR is the type of the data going into the kernel or coming
33 out of the kernel (e.g. 'int' or 'struct foo'). NOTE! Do NOT use
34 sizeof(arg) as the third argument as this results in your ioctl thinking
35 it passes an argument of type size_t.
37 Some devices use their major number as the identifier; this is OK, as
38 long as it is unique. Some devices are irregular and don't follow any
41 Following this convention is good because:
43 (1) Keeping the ioctl's globally unique helps error checking:
44 if a program calls an ioctl on the wrong device, it will get an
45 error rather than some unexpected behaviour.
47 (2) The 'strace' build procedure automatically finds ioctl numbers
48 defined with _IO, _IOW, _IOR, or _IOWR.
50 (3) 'strace' can decode numbers back into useful names when the
53 (4) People looking for ioctls can grep for them more easily when
54 this convention is used to define the ioctl numbers.
56 (5) When following the convention, the driver code can use generic
57 code to copy the parameters between user and kernel space.
59 This table lists ioctls visible from user land for Linux/x86. It contains
60 most drivers up to 2.6.31, but I know I am missing some. There has been
61 no attempt to list non-X86 architectures or ioctls from drivers/staging/.
63 Code Seq#(hex) Include File Comments
64 ========================================================
65 0x00 00-1F linux/fs.h conflict!
66 0x00 00-1F scsi/scsi_ioctl.h conflict!
67 0x00 00-1F linux/fb.h conflict!
68 0x00 00-1F linux/wavefront.h conflict!
70 0x03 all linux/hdreg.h
71 0x04 D2-DC linux/umsdos_fs.h Dead since 2.6.11, but don't reuse these.
73 0x09 all linux/raid/md_u.h
74 0x10 00-0F drivers/char/s390/vmcp.h
75 0x10 10-1F arch/s390/include/uapi/sclp_ctl.h
76 0x10 20-2F arch/s390/include/uapi/asm/hypfs.h
79 0x1b all InfiniBand Subsystem <http://infiniband.sourceforge.net/>
80 0x20 all drivers/cdrom/cm206.h
82 '#' 00-3F IEEE 1394 Subsystem Block for the entire subsystem
83 '$' 00-0F linux/perf_counter.h, linux/perf_event.h
84 '%' 00-0F include/uapi/linux/stm.h
85 System Trace Module subsystem
86 <mailto:alexander.shishkin@linux.intel.com>
87 '&' 00-07 drivers/firewire/nosy-user.h
88 '1' 00-1F <linux/timepps.h> PPS kit from Ulrich Windl
89 <ftp://ftp.de.kernel.org/pub/linux/daemons/ntp/PPS/>
91 '3' 00-0F drivers/s390/char/raw3270.h conflict!
92 '3' 00-1F linux/suspend_ioctls.h conflict!
93 and kernel/power/user.c
94 '8' all SNP8023 advanced NIC card
95 <mailto:mcr@solidum.com>
96 ';' 64-7F linux/vfio.h
97 '@' 00-0F linux/radeonfb.h conflict!
98 '@' 00-0F drivers/video/aty/aty128fb.c conflict!
99 'A' 00-1F linux/apm_bios.h conflict!
100 'A' 00-0F linux/agpgart.h conflict!
101 and drivers/char/agp/compat_ioctl.h
102 'A' 00-7F sound/asound.h conflict!
103 'B' 00-1F linux/cciss_ioctl.h conflict!
104 'B' 00-0F include/linux/pmu.h conflict!
105 'B' C0-FF advanced bbus
106 <mailto:maassen@uni-freiburg.de>
107 'C' all linux/soundcard.h conflict!
108 'C' 01-2F linux/capi.h conflict!
109 'C' F0-FF drivers/net/wan/cosa.h conflict!
110 'D' all arch/s390/include/asm/dasd.h
111 'D' 40-5F drivers/scsi/dpt/dtpi_ioctl.h
112 'D' 05 drivers/scsi/pmcraid.h
113 'E' all linux/input.h conflict!
114 'E' 00-0F xen/evtchn.h conflict!
115 'F' all linux/fb.h conflict!
116 'F' 01-02 drivers/scsi/pmcraid.h conflict!
117 'F' 20 drivers/video/fsl-diu-fb.h conflict!
118 'F' 20 drivers/video/intelfb/intelfb.h conflict!
119 'F' 20 linux/ivtvfb.h conflict!
120 'F' 20 linux/matroxfb.h conflict!
121 'F' 20 drivers/video/aty/atyfb_base.c conflict!
122 'F' 00-0F video/da8xx-fb.h conflict!
123 'F' 80-8F linux/arcfb.h conflict!
124 'F' DD video/sstfb.h conflict!
125 'G' 00-3F drivers/misc/sgi-gru/grulib.h conflict!
126 'G' 00-0F linux/gigaset_dev.h conflict!
127 'H' 00-7F linux/hiddev.h conflict!
128 'H' 00-0F linux/hidraw.h conflict!
129 'H' 01 linux/mei.h conflict!
130 'H' 02 linux/mei.h conflict!
131 'H' 03 linux/mei.h conflict!
132 'H' 00-0F sound/asound.h conflict!
133 'H' 20-40 sound/asound_fm.h conflict!
134 'H' 80-8F sound/sfnt_info.h conflict!
135 'H' 10-8F sound/emu10k1.h conflict!
136 'H' 10-1F sound/sb16_csp.h conflict!
137 'H' 10-1F sound/hda_hwdep.h conflict!
138 'H' 40-4F sound/hdspm.h conflict!
139 'H' 40-4F sound/hdsp.h conflict!
140 'H' 90 sound/usb/usx2y/usb_stream.h
141 'H' A0 uapi/linux/usb/cdc-wdm.h
142 'H' C0-F0 net/bluetooth/hci.h conflict!
143 'H' C0-DF net/bluetooth/hidp/hidp.h conflict!
144 'H' C0-DF net/bluetooth/cmtp/cmtp.h conflict!
145 'H' C0-DF net/bluetooth/bnep/bnep.h conflict!
146 'H' F1 linux/hid-roccat.h <mailto:erazor_de@users.sourceforge.net>
147 'H' F8-FA sound/firewire.h
148 'I' all linux/isdn.h conflict!
149 'I' 00-0F drivers/isdn/divert/isdn_divert.h conflict!
150 'I' 40-4F linux/mISDNif.h conflict!
151 'J' 00-1F drivers/scsi/gdth_ioctl.h
153 'L' 00-1F linux/loop.h conflict!
154 'L' 10-1F drivers/scsi/mpt2sas/mpt2sas_ctl.h conflict!
155 'L' E0-FF linux/ppdd.h encrypted disk device driver
156 <http://linux01.gwdg.de/~alatham/ppdd.html>
157 'M' all linux/soundcard.h conflict!
158 'M' 01-16 mtd/mtd-abi.h conflict!
159 and drivers/mtd/mtdchar.c
160 'M' 01-03 drivers/scsi/megaraid/megaraid_sas.h
161 'M' 00-0F drivers/video/fsl-diu-fb.h conflict!
162 'N' 00-1F drivers/usb/scanner.h
163 'N' 40-7F drivers/block/nvme.c
164 'O' 00-06 mtd/ubi-user.h UBI
165 'P' all linux/soundcard.h conflict!
166 'P' 60-6F sound/sscape_ioctl.h conflict!
167 'P' 00-0F drivers/usb/class/usblp.c conflict!
168 'Q' all linux/soundcard.h
169 'R' 00-1F linux/random.h conflict!
170 'R' 01 linux/rfkill.h conflict!
171 'R' C0-DF net/bluetooth/rfcomm.h
172 'S' all linux/cdrom.h conflict!
173 'S' 80-81 scsi/scsi_ioctl.h conflict!
174 'S' 82-FF scsi/scsi.h conflict!
175 'S' 00-7F sound/asequencer.h conflict!
176 'T' all linux/soundcard.h conflict!
177 'T' 00-AF sound/asound.h conflict!
178 'T' all arch/x86/include/asm/ioctls.h conflict!
179 'T' C0-DF linux/if_tun.h conflict!
180 'U' all sound/asound.h conflict!
181 'U' 00-CF linux/uinput.h conflict!
182 'U' 00-EF linux/usbdevice_fs.h
183 'U' C0-CF drivers/bluetooth/hci_uart.h
184 'V' all linux/vt.h conflict!
185 'V' all linux/videodev2.h conflict!
186 'V' C0 linux/ivtvfb.h conflict!
187 'V' C0 linux/ivtv.h conflict!
188 'V' C0 media/davinci/vpfe_capture.h conflict!
189 'V' C0 media/si4713.h conflict!
190 'W' 00-1F linux/watchdog.h conflict!
191 'W' 00-1F linux/wanrouter.h conflict! (pre 3.9)
192 'W' 00-3F sound/asound.h conflict!
193 'X' all fs/xfs/xfs_fs.h conflict!
194 and fs/xfs/linux-2.6/xfs_ioctl32.h
195 and include/linux/falloc.h
197 'X' all fs/ocfs2/ocfs_fs.h conflict!
198 'X' 01 linux/pktcdvd.h conflict!
199 'Y' all linux/cyclades.h
200 'Z' 14-15 drivers/message/fusion/mptctl.h
201 '[' 00-07 linux/usb/tmc.h USB Test and Measurement Devices
202 <mailto:gregkh@linuxfoundation.org>
203 'a' all linux/atm*.h, linux/sonet.h ATM on linux
204 <http://lrcwww.epfl.ch/>
205 'a' 00-0F drivers/crypto/qat/qat_common/adf_cfg_common.h conflict! qat driver
206 'b' 00-FF conflict! bit3 vme host bridge
207 <mailto:natalia@nikhefk.nikhef.nl>
208 'c' all linux/cm4000_cs.h conflict!
209 'c' 00-7F linux/comstats.h conflict!
210 'c' 00-7F linux/coda.h conflict!
211 'c' 00-1F linux/chio.h conflict!
212 'c' 80-9F arch/s390/include/asm/chsc.h conflict!
213 'c' A0-AF arch/x86/include/asm/msr.h conflict!
214 'd' 00-FF linux/char/drm/drm/h conflict!
215 'd' 02-40 pcmcia/ds.h conflict!
216 'd' F0-FF linux/digi1.h
217 'e' all linux/digi1.h conflict!
218 'e' 00-1F drivers/net/irda/irtty-sir.h conflict!
219 'f' 00-1F linux/ext2_fs.h conflict!
220 'f' 00-1F linux/ext3_fs.h conflict!
221 'f' 00-0F fs/jfs/jfs_dinode.h conflict!
222 'f' 00-0F fs/ext4/ext4.h conflict!
223 'f' 00-0F linux/fs.h conflict!
224 'f' 00-0F fs/ocfs2/ocfs2_fs.h conflict!
225 'g' 00-0F linux/usb/gadgetfs.h
226 'g' 20-2F linux/usb/g_printer.h
227 'h' 00-7F conflict! Charon filesystem
228 <mailto:zapman@interlan.net>
229 'h' 00-1F linux/hpet.h conflict!
230 'h' 80-8F fs/hfsplus/ioctl.c
231 'i' 00-3F linux/i2o-dev.h conflict!
232 'i' 0B-1F linux/ipmi.h conflict!
233 'i' 80-8F linux/i8k.h
234 'j' 00-3F linux/joystick.h
235 'k' 00-0F linux/spi/spidev.h conflict!
236 'k' 00-05 video/kyro.h conflict!
237 'k' 10-17 linux/hsi/hsi_char.h HSI character device
238 'l' 00-3F linux/tcfs_fs.h transparent cryptographic file system
239 <http://web.archive.org/web/*/http://mikonos.dia.unisa.it/tcfs>
240 'l' 40-7F linux/udf_fs_i.h in development:
241 <http://sourceforge.net/projects/linux-udf/>
242 'm' 00-09 linux/mmtimer.h conflict!
243 'm' all linux/mtio.h conflict!
244 'm' all linux/soundcard.h conflict!
245 'm' all linux/synclink.h conflict!
246 'm' 00-19 drivers/message/fusion/mptctl.h conflict!
247 'm' 00 drivers/scsi/megaraid/megaraid_ioctl.h conflict!
248 'm' 00-1F net/irda/irmod.h conflict!
249 'n' 00-7F linux/ncp_fs.h and fs/ncpfs/ioctl.c
250 'n' 80-8F linux/nilfs2_fs.h NILFS2
251 'n' E0-FF linux/matroxfb.h matroxfb
252 'o' 00-1F fs/ocfs2/ocfs2_fs.h OCFS2
253 'o' 00-03 mtd/ubi-user.h conflict! (OCFS2 and UBI overlaps)
254 'o' 40-41 mtd/ubi-user.h UBI
255 'o' 01-A1 linux/dvb/*.h DVB
256 'p' 00-0F linux/phantom.h conflict! (OpenHaptics needs this)
257 'p' 00-1F linux/rtc.h conflict!
258 'p' 00-3F linux/mc146818rtc.h conflict!
259 'p' 40-7F linux/nvram.h
260 'p' 80-9F linux/ppdev.h user-space parport
261 <mailto:tim@cyberelk.net>
262 'p' A1-A5 linux/pps.h LinuxPPS
263 <mailto:giometti@linux.it>
264 'q' 00-1F linux/serio.h
265 'q' 80-FF linux/telephony.h Internet PhoneJACK, Internet LineJACK
266 linux/ixjuser.h <http://web.archive.org/web/*/http://www.quicknet.net>
267 'r' 00-1F linux/msdos_fs.h and fs/fat/dir.c
269 't' 00-7F linux/ppp-ioctl.h
270 't' 80-8F linux/isdn_ppp.h
271 't' 90-91 linux/toshiba.h toshiba and toshiba_acpi SMM
272 'u' 00-1F linux/smb_fs.h gone
273 'u' 20-3F linux/uvcvideo.h USB video class host driver
274 'v' 00-1F linux/ext2_fs.h conflict!
275 'v' 00-1F linux/fs.h conflict!
276 'v' 00-0F linux/sonypi.h conflict!
277 'v' C0-FF linux/meye.h conflict!
278 'w' all CERN SCI driver
279 'y' 00-1F packet based user level communications
280 <mailto:zapman@interlan.net>
281 'z' 00-3F CAN bus card conflict!
282 <mailto:hdstich@connectu.ulm.circular.de>
283 'z' 40-7F CAN bus card conflict!
285 'z' 10-4F drivers/s390/crypto/zcrypt_api.h conflict!
286 '|' 00-7F linux/media.h
287 0x80 00-1F linux/fb.h
288 0x89 00-06 arch/x86/include/asm/sockios.h
289 0x89 0B-DF linux/sockios.h
290 0x89 E0-EF linux/sockios.h SIOCPROTOPRIVATE range
291 0x89 E0-EF linux/dn.h PROTOPRIVATE range
292 0x89 F0-FF linux/sockios.h SIOCDEVPRIVATE range
293 0x8B all linux/wireless.h
294 0x8C 00-3F WiNRADiO driver
295 <http://www.winradio.com.au/>
296 0x90 00 drivers/cdrom/sbpcd.h
297 0x92 00-0F drivers/usb/mon/mon_bin.c
298 0x93 60-7F linux/auto_fs.h
299 0x94 all fs/btrfs/ioctl.h
300 0x97 00-7F fs/ceph/ioctl.h Ceph file system
301 0x99 00-0F 537-Addinboard driver
302 <mailto:buk@buks.ipn.de>
303 0xA0 all linux/sdp/sdp.h Industrial Device Project
304 <mailto:kenji@bitgate.com>
305 0xA2 00-0F arch/tile/include/asm/hardwall.h
306 0xA3 80-8F Port ACL in development:
307 <mailto:tlewis@mindspring.com>
308 0xA3 90-9F linux/dtlk.h
309 0xAA 00-3F linux/uapi/linux/userfaultfd.h
310 0xAB 00-1F linux/nbd.h
311 0xAC 00-1F linux/raw.h
312 0xAD 00 Netfilter device in development:
313 <mailto:rusty@rustcorp.com.au>
314 0xAE all linux/kvm.h Kernel-based Virtual Machine
315 <mailto:kvm@vger.kernel.org>
316 0xAF 00-1F linux/fsl_hypervisor.h Freescale hypervisor
317 0xB0 all RATIO devices in development:
318 <mailto:vgo@ratio.de>
319 0xB1 00-1F PPPoX <mailto:mostrows@styx.uwaterloo.ca>
320 0xB3 00 linux/mmc/ioctl.h
321 0xC0 00-0F linux/usb/iowarrior.h
322 0xCA 00-0F uapi/misc/cxl.h
323 0xCA 80-8F uapi/scsi/cxlflash_ioctl.h
324 0xCB 00-1F CBM serial IEC bus in development:
325 <mailto:michael.klein@puffin.lb.shuttle.de>
326 0xCD 01 linux/reiserfs_fs.h
327 0xCF 02 fs/cifs/ioctl.c
328 0xDB 00-0F drivers/char/mwave/mwavepub.h
329 0xDD 00-3F ZFCP device driver see drivers/s390/scsi/
330 <mailto:aherrman@de.ibm.com>
331 0xE5 00-3F linux/fuse.h
332 0xEC 00-01 drivers/platform/chrome/cros_ec_dev.h ChromeOS EC driver
333 0xF3 00-3F drivers/usb/misc/sisusbvga/sisusb.h sisfb (in development)
334 <mailto:thomas@winischhofer.net>
335 0xF4 00-1F video/mbxfb.h mbxfb
337 0xF6 all LTTng Linux Trace Toolkit Next Generation
338 <mailto:mathieu.desnoyers@efficios.com>
339 0xFD all linux/dm-ioctl.h