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 'G' 00-0F linux/gigaset_dev.h conflict!
136 'H' 00-7F linux/hiddev.h conflict!
137 'H' 00-0F linux/hidraw.h conflict!
138 'H' 01 linux/mei.h conflict!
139 'H' 02 linux/mei.h conflict!
140 'H' 03 linux/mei.h conflict!
141 'H' 00-0F sound/asound.h conflict!
142 'H' 20-40 sound/asound_fm.h conflict!
143 'H' 80-8F sound/sfnt_info.h conflict!
144 'H' 10-8F sound/emu10k1.h conflict!
145 'H' 10-1F sound/sb16_csp.h conflict!
146 'H' 10-1F sound/hda_hwdep.h conflict!
147 'H' 40-4F sound/hdspm.h conflict!
148 'H' 40-4F sound/hdsp.h conflict!
149 'H' 90 sound/usb/usx2y/usb_stream.h
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 'J' 00-1F drivers/scsi/gdth_ioctl.h
162 'L' 00-1F linux/loop.h conflict!
163 'L' 10-1F drivers/scsi/mpt3sas/mpt3sas_ctl.h conflict!
164 'L' 20-2F linux/lightnvm.h
165 'L' E0-FF linux/ppdd.h encrypted disk device driver
166 <http://linux01.gwdg.de/~alatham/ppdd.html>
167 'M' all linux/soundcard.h conflict!
168 'M' 01-16 mtd/mtd-abi.h conflict!
169 and drivers/mtd/mtdchar.c
170 'M' 01-03 drivers/scsi/megaraid/megaraid_sas.h
171 'M' 00-0F drivers/video/fsl-diu-fb.h conflict!
172 'N' 00-1F drivers/usb/scanner.h
173 'N' 40-7F drivers/block/nvme.c
174 'O' 00-06 mtd/ubi-user.h UBI
175 'P' all linux/soundcard.h conflict!
176 'P' 60-6F sound/sscape_ioctl.h conflict!
177 'P' 00-0F drivers/usb/class/usblp.c conflict!
178 'P' 01-09 drivers/misc/pci_endpoint_test.c conflict!
179 'Q' all linux/soundcard.h
180 'R' 00-1F linux/random.h conflict!
181 'R' 01 linux/rfkill.h conflict!
182 'R' C0-DF net/bluetooth/rfcomm.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 'X' all fs/xfs/xfs_fs.h, conflict!
206 fs/xfs/linux-2.6/xfs_ioctl32.h,
207 include/linux/falloc.h,
209 'X' all fs/ocfs2/ocfs_fs.h conflict!
210 'X' 01 linux/pktcdvd.h conflict!
211 'Y' all linux/cyclades.h
212 'Z' 14-15 drivers/message/fusion/mptctl.h
213 '[' 00-3F linux/usb/tmc.h USB Test and Measurement Devices
214 <mailto:gregkh@linuxfoundation.org>
215 'a' all linux/atm*.h, linux/sonet.h ATM on linux
216 <http://lrcwww.epfl.ch/>
217 'a' 00-0F drivers/crypto/qat/qat_common/adf_cfg_common.h conflict! qat driver
218 'b' 00-FF conflict! bit3 vme host bridge
219 <mailto:natalia@nikhefk.nikhef.nl>
220 'c' all linux/cm4000_cs.h conflict!
221 'c' 00-7F linux/comstats.h conflict!
222 'c' 00-7F linux/coda.h conflict!
223 'c' 00-1F linux/chio.h conflict!
224 'c' 80-9F arch/s390/include/asm/chsc.h conflict!
225 'c' A0-AF arch/x86/include/asm/msr.h conflict!
226 'd' 00-FF linux/char/drm/drm.h conflict!
227 'd' 02-40 pcmcia/ds.h conflict!
228 'd' F0-FF linux/digi1.h
229 'e' all linux/digi1.h conflict!
230 'f' 00-1F linux/ext2_fs.h conflict!
231 'f' 00-1F linux/ext3_fs.h conflict!
232 'f' 00-0F fs/jfs/jfs_dinode.h conflict!
233 'f' 00-0F fs/ext4/ext4.h conflict!
234 'f' 00-0F linux/fs.h conflict!
235 'f' 00-0F fs/ocfs2/ocfs2_fs.h conflict!
236 'f' 81-8F linux/fsverity.h
237 'g' 00-0F linux/usb/gadgetfs.h
238 'g' 20-2F linux/usb/g_printer.h
239 'h' 00-7F conflict! Charon filesystem
240 <mailto:zapman@interlan.net>
241 'h' 00-1F linux/hpet.h conflict!
242 'h' 80-8F fs/hfsplus/ioctl.c
243 'i' 00-3F linux/i2o-dev.h conflict!
244 'i' 0B-1F linux/ipmi.h conflict!
245 'i' 80-8F linux/i8k.h
246 'j' 00-3F linux/joystick.h
247 'k' 00-0F linux/spi/spidev.h conflict!
248 'k' 00-05 video/kyro.h conflict!
249 'k' 10-17 linux/hsi/hsi_char.h HSI character device
250 'l' 00-3F linux/tcfs_fs.h transparent cryptographic file system
251 <http://web.archive.org/web/%2A/http://mikonos.dia.unisa.it/tcfs>
252 'l' 40-7F linux/udf_fs_i.h in development:
253 <http://sourceforge.net/projects/linux-udf/>
254 'm' 00-09 linux/mmtimer.h conflict!
255 'm' all linux/mtio.h conflict!
256 'm' all linux/soundcard.h conflict!
257 'm' all linux/synclink.h conflict!
258 'm' 00-19 drivers/message/fusion/mptctl.h conflict!
259 'm' 00 drivers/scsi/megaraid/megaraid_ioctl.h conflict!
260 'n' 00-7F linux/ncp_fs.h and fs/ncpfs/ioctl.c
261 'n' 80-8F uapi/linux/nilfs2_api.h NILFS2
262 'n' E0-FF linux/matroxfb.h matroxfb
263 'o' 00-1F fs/ocfs2/ocfs2_fs.h OCFS2
264 'o' 00-03 mtd/ubi-user.h conflict! (OCFS2 and UBI overlaps)
265 'o' 40-41 mtd/ubi-user.h UBI
266 'o' 01-A1 `linux/dvb/*.h` DVB
267 'p' 00-0F linux/phantom.h conflict! (OpenHaptics needs this)
268 'p' 00-1F linux/rtc.h conflict!
269 'p' 00-3F linux/mc146818rtc.h conflict!
270 'p' 40-7F linux/nvram.h
271 'p' 80-9F linux/ppdev.h user-space parport
272 <mailto:tim@cyberelk.net>
273 'p' A1-A5 linux/pps.h LinuxPPS
274 <mailto:giometti@linux.it>
275 'q' 00-1F linux/serio.h
276 'q' 80-FF linux/telephony.h Internet PhoneJACK, Internet LineJACK
277 linux/ixjuser.h <http://web.archive.org/web/%2A/http://www.quicknet.net>
278 'r' 00-1F linux/msdos_fs.h and fs/fat/dir.c
280 't' 00-7F linux/ppp-ioctl.h
281 't' 80-8F linux/isdn_ppp.h
282 't' 90-91 linux/toshiba.h toshiba and toshiba_acpi SMM
283 'u' 00-1F linux/smb_fs.h gone
284 'u' 20-3F linux/uvcvideo.h USB video class host driver
285 'u' 40-4f linux/udmabuf.h userspace dma-buf misc device
286 'v' 00-1F linux/ext2_fs.h conflict!
287 'v' 00-1F linux/fs.h conflict!
288 'v' 00-0F linux/sonypi.h conflict!
289 'v' 00-0F media/v4l2-subdev.h conflict!
290 'v' C0-FF linux/meye.h conflict!
291 'w' all CERN SCI driver
292 'y' 00-1F packet based user level communications
293 <mailto:zapman@interlan.net>
294 'z' 00-3F CAN bus card conflict!
295 <mailto:hdstich@connectu.ulm.circular.de>
296 'z' 40-7F CAN bus card conflict!
298 'z' 10-4F drivers/s390/crypto/zcrypt_api.h conflict!
299 '|' 00-7F linux/media.h
300 0x80 00-1F linux/fb.h
301 0x89 00-06 arch/x86/include/asm/sockios.h
302 0x89 0B-DF linux/sockios.h
303 0x89 E0-EF linux/sockios.h SIOCPROTOPRIVATE range
304 0x89 E0-EF linux/dn.h PROTOPRIVATE range
305 0x89 F0-FF linux/sockios.h SIOCDEVPRIVATE range
306 0x8B all linux/wireless.h
307 0x8C 00-3F WiNRADiO driver
308 <http://www.winradio.com.au/>
309 0x90 00 drivers/cdrom/sbpcd.h
310 0x92 00-0F drivers/usb/mon/mon_bin.c
311 0x93 60-7F linux/auto_fs.h
312 0x94 all fs/btrfs/ioctl.h Btrfs filesystem
313 and linux/fs.h some lifted to vfs/generic
314 0x97 00-7F fs/ceph/ioctl.h Ceph file system
315 0x99 00-0F 537-Addinboard driver
316 <mailto:buk@buks.ipn.de>
317 0xA0 all linux/sdp/sdp.h Industrial Device Project
318 <mailto:kenji@bitgate.com>
319 0xA1 0 linux/vtpm_proxy.h TPM Emulator Proxy Driver
320 0xA3 80-8F Port ACL in development:
321 <mailto:tlewis@mindspring.com>
322 0xA3 90-9F linux/dtlk.h
323 0xA4 00-1F uapi/linux/tee.h Generic TEE subsystem
324 0xAA 00-3F linux/uapi/linux/userfaultfd.h
325 0xAB 00-1F linux/nbd.h
326 0xAC 00-1F linux/raw.h
327 0xAD 00 Netfilter device in development:
328 <mailto:rusty@rustcorp.com.au>
329 0xAE all linux/kvm.h Kernel-based Virtual Machine
330 <mailto:kvm@vger.kernel.org>
331 0xAF 00-1F linux/fsl_hypervisor.h Freescale hypervisor
332 0xB0 all RATIO devices in development:
333 <mailto:vgo@ratio.de>
335 <mailto:mostrows@styx.uwaterloo.ca>
336 0xB3 00 linux/mmc/ioctl.h
337 0xB4 00-0F linux/gpio.h <mailto:linux-gpio@vger.kernel.org>
338 0xB5 00-0F uapi/linux/rpmsg.h <mailto:linux-remoteproc@vger.kernel.org>
339 0xB6 all linux/fpga-dfl.h
340 0xC0 00-0F linux/usb/iowarrior.h
341 0xCA 00-0F uapi/misc/cxl.h
342 0xCA 10-2F uapi/misc/ocxl.h
343 0xCA 80-BF uapi/scsi/cxlflash_ioctl.h
344 0xCB 00-1F CBM serial IEC bus in development:
345 <mailto:michael.klein@puffin.lb.shuttle.de>
346 0xCC 00-0F drivers/misc/ibmvmc.h pseries VMC driver
347 0xCD 01 linux/reiserfs_fs.h
348 0xCF 02 fs/cifs/ioctl.c
349 0xDB 00-0F drivers/char/mwave/mwavepub.h
350 0xDD 00-3F ZFCP device driver see drivers/s390/scsi/
351 <mailto:aherrman@de.ibm.com>
352 0xE5 00-3F linux/fuse.h
353 0xEC 00-01 drivers/platform/chrome/cros_ec_dev.h ChromeOS EC driver
354 0xF3 00-3F drivers/usb/misc/sisusbvga/sisusb.h sisfb (in development)
355 <mailto:thomas@winischhofer.net>
356 0xF4 00-1F video/mbxfb.h mbxfb
358 0xF6 all LTTng Linux Trace Toolkit Next Generation
359 <mailto:mathieu.desnoyers@efficios.com>
360 0xFD all linux/dm-ioctl.h
361 0xFE all linux/isst_if.h
362 ==== ===== ======================================================= ================================================================