![Tycho Andersen](/assets/img/avatar_default.png)
This patch introduces a means for syscalls matched in seccomp to notify some other task that a particular filter has been triggered. The motivation for this is primarily for use with containers. For example, if a container does an init_module(), we obviously don't want to load this untrusted code, which may be compiled for the wrong version of the kernel anyway. Instead, we could parse the module image, figure out which module the container is trying to load and load it on the host. As another example, containers cannot mount() in general since various filesystems assume a trusted image. However, if an orchestrator knows that e.g. a particular block device has not been exposed to a container for writing, it want to allow the container to mount that block device (that is, handle the mount for it). This patch adds functionality that is already possible via at least two other means that I know about, both of which involve ptrace(): first, one could ptrace attach, and then iterate through syscalls via PTRACE_SYSCALL. Unfortunately this is slow, so a faster version would be to install a filter that does SECCOMP_RET_TRACE, which triggers a PTRACE_EVENT_SECCOMP. Since ptrace allows only one tracer, if the container runtime is that tracer, users inside the container (or outside) trying to debug it will not be able to use ptrace, which is annoying. It also means that older distributions based on Upstart cannot boot inside containers using ptrace, since upstart itself uses ptrace to monitor services while starting. The actual implementation of this is fairly small, although getting the synchronization right was/is slightly complex. Finally, it's worth noting that the classic seccomp TOCTOU of reading memory data from the task still applies here, but can be avoided with careful design of the userspace handler: if the userspace handler reads all of the task memory that is necessary before applying its security policy, the tracee's subsequent memory edits will not be read by the tracer. Signed-off-by: Tycho Andersen <tycho@tycho.ws> CC: Kees Cook <keescook@chromium.org> CC: Andy Lutomirski <luto@amacapital.net> CC: Oleg Nesterov <oleg@redhat.com> CC: Eric W. Biederman <ebiederm@xmission.com> CC: "Serge E. Hallyn" <serge@hallyn.com> Acked-by: Serge Hallyn <serge@hallyn.com> CC: Christian Brauner <christian@brauner.io> CC: Tyler Hicks <tyhicks@canonical.com> CC: Akihiro Suda <suda.akihiro@lab.ntt.co.jp> Signed-off-by: Kees Cook <keescook@chromium.org>
351 lines
13 KiB
Plaintext
351 lines
13 KiB
Plaintext
Ioctl Numbers
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19 October 1999
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Michael Elizabeth Chastain
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<mec@shout.net>
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If you are adding new ioctl's to the kernel, you should use the _IO
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macros defined in <linux/ioctl.h>:
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_IO an ioctl with no parameters
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_IOW an ioctl with write parameters (copy_from_user)
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_IOR an ioctl with read parameters (copy_to_user)
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_IOWR an ioctl with both write and read parameters.
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'Write' and 'read' are from the user's point of view, just like the
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system calls 'write' and 'read'. For example, a SET_FOO ioctl would
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be _IOW, although the kernel would actually read data from user space;
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a GET_FOO ioctl would be _IOR, although the kernel would actually write
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data to user space.
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The first argument to _IO, _IOW, _IOR, or _IOWR is an identifying letter
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or number from the table below. Because of the large number of drivers,
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many drivers share a partial letter with other drivers.
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If you are writing a driver for a new device and need a letter, pick an
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unused block with enough room for expansion: 32 to 256 ioctl commands.
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You can register the block by patching this file and submitting the
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patch to Linus Torvalds. Or you can e-mail me at <mec@shout.net> and
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I'll register one for you.
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The second argument to _IO, _IOW, _IOR, or _IOWR is a sequence number
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to distinguish ioctls from each other. The third argument to _IOW,
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_IOR, or _IOWR is the type of the data going into the kernel or coming
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out of the kernel (e.g. 'int' or 'struct foo'). NOTE! Do NOT use
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sizeof(arg) as the third argument as this results in your ioctl thinking
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it passes an argument of type size_t.
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Some devices use their major number as the identifier; this is OK, as
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long as it is unique. Some devices are irregular and don't follow any
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convention at all.
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Following this convention is good because:
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(1) Keeping the ioctl's globally unique helps error checking:
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if a program calls an ioctl on the wrong device, it will get an
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error rather than some unexpected behaviour.
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(2) The 'strace' build procedure automatically finds ioctl numbers
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defined with _IO, _IOW, _IOR, or _IOWR.
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(3) 'strace' can decode numbers back into useful names when the
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numbers are unique.
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(4) People looking for ioctls can grep for them more easily when
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this convention is used to define the ioctl numbers.
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(5) When following the convention, the driver code can use generic
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code to copy the parameters between user and kernel space.
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This table lists ioctls visible from user land for Linux/x86. It contains
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most drivers up to 2.6.31, but I know I am missing some. There has been
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no attempt to list non-X86 architectures or ioctls from drivers/staging/.
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Code Seq#(hex) Include File Comments
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========================================================
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0x00 00-1F linux/fs.h conflict!
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0x00 00-1F scsi/scsi_ioctl.h conflict!
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0x00 00-1F linux/fb.h conflict!
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0x00 00-1F linux/wavefront.h conflict!
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0x02 all linux/fd.h
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0x03 all linux/hdreg.h
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0x04 D2-DC linux/umsdos_fs.h Dead since 2.6.11, but don't reuse these.
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0x06 all linux/lp.h
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0x09 all linux/raid/md_u.h
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0x10 00-0F drivers/char/s390/vmcp.h
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0x10 10-1F arch/s390/include/uapi/sclp_ctl.h
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0x10 20-2F arch/s390/include/uapi/asm/hypfs.h
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0x12 all linux/fs.h
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linux/blkpg.h
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0x1b all InfiniBand Subsystem <http://infiniband.sourceforge.net/>
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0x20 all drivers/cdrom/cm206.h
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0x22 all scsi/sg.h
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'!' 00-1F uapi/linux/seccomp.h
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'#' 00-3F IEEE 1394 Subsystem Block for the entire subsystem
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'$' 00-0F linux/perf_counter.h, linux/perf_event.h
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'%' 00-0F include/uapi/linux/stm.h
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System Trace Module subsystem
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<mailto:alexander.shishkin@linux.intel.com>
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'&' 00-07 drivers/firewire/nosy-user.h
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'1' 00-1F <linux/timepps.h> PPS kit from Ulrich Windl
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<ftp://ftp.de.kernel.org/pub/linux/daemons/ntp/PPS/>
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'2' 01-04 linux/i2o.h
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'3' 00-0F drivers/s390/char/raw3270.h conflict!
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'3' 00-1F linux/suspend_ioctls.h conflict!
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and kernel/power/user.c
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'8' all SNP8023 advanced NIC card
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<mailto:mcr@solidum.com>
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';' 64-7F linux/vfio.h
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'@' 00-0F linux/radeonfb.h conflict!
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'@' 00-0F drivers/video/aty/aty128fb.c conflict!
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'A' 00-1F linux/apm_bios.h conflict!
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'A' 00-0F linux/agpgart.h conflict!
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and drivers/char/agp/compat_ioctl.h
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'A' 00-7F sound/asound.h conflict!
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'B' 00-1F linux/cciss_ioctl.h conflict!
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'B' 00-0F include/linux/pmu.h conflict!
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'B' C0-FF advanced bbus
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<mailto:maassen@uni-freiburg.de>
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'C' all linux/soundcard.h conflict!
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'C' 01-2F linux/capi.h conflict!
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'C' F0-FF drivers/net/wan/cosa.h conflict!
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'D' all arch/s390/include/asm/dasd.h
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'D' 40-5F drivers/scsi/dpt/dtpi_ioctl.h
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'D' 05 drivers/scsi/pmcraid.h
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'E' all linux/input.h conflict!
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'E' 00-0F xen/evtchn.h conflict!
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'F' all linux/fb.h conflict!
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'F' 01-02 drivers/scsi/pmcraid.h conflict!
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'F' 20 drivers/video/fsl-diu-fb.h conflict!
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'F' 20 drivers/video/intelfb/intelfb.h conflict!
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'F' 20 linux/ivtvfb.h conflict!
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'F' 20 linux/matroxfb.h conflict!
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'F' 20 drivers/video/aty/atyfb_base.c conflict!
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'F' 00-0F video/da8xx-fb.h conflict!
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'F' 80-8F linux/arcfb.h conflict!
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'F' DD video/sstfb.h conflict!
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'G' 00-3F drivers/misc/sgi-gru/grulib.h conflict!
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'G' 00-0F linux/gigaset_dev.h conflict!
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'H' 00-7F linux/hiddev.h conflict!
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'H' 00-0F linux/hidraw.h conflict!
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'H' 01 linux/mei.h conflict!
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'H' 02 linux/mei.h conflict!
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'H' 03 linux/mei.h conflict!
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'H' 00-0F sound/asound.h conflict!
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'H' 20-40 sound/asound_fm.h conflict!
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'H' 80-8F sound/sfnt_info.h conflict!
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'H' 10-8F sound/emu10k1.h conflict!
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'H' 10-1F sound/sb16_csp.h conflict!
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'H' 10-1F sound/hda_hwdep.h conflict!
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'H' 40-4F sound/hdspm.h conflict!
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'H' 40-4F sound/hdsp.h conflict!
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'H' 90 sound/usb/usx2y/usb_stream.h
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'H' A0 uapi/linux/usb/cdc-wdm.h
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'H' C0-F0 net/bluetooth/hci.h conflict!
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'H' C0-DF net/bluetooth/hidp/hidp.h conflict!
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'H' C0-DF net/bluetooth/cmtp/cmtp.h conflict!
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'H' C0-DF net/bluetooth/bnep/bnep.h conflict!
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'H' F1 linux/hid-roccat.h <mailto:erazor_de@users.sourceforge.net>
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'H' F8-FA sound/firewire.h
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'I' all linux/isdn.h conflict!
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'I' 00-0F drivers/isdn/divert/isdn_divert.h conflict!
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'I' 40-4F linux/mISDNif.h conflict!
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'J' 00-1F drivers/scsi/gdth_ioctl.h
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'K' all linux/kd.h
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'L' 00-1F linux/loop.h conflict!
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'L' 10-1F drivers/scsi/mpt3sas/mpt3sas_ctl.h conflict!
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'L' 20-2F linux/lightnvm.h
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'L' E0-FF linux/ppdd.h encrypted disk device driver
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<http://linux01.gwdg.de/~alatham/ppdd.html>
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'M' all linux/soundcard.h conflict!
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'M' 01-16 mtd/mtd-abi.h conflict!
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and drivers/mtd/mtdchar.c
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'M' 01-03 drivers/scsi/megaraid/megaraid_sas.h
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'M' 00-0F drivers/video/fsl-diu-fb.h conflict!
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'N' 00-1F drivers/usb/scanner.h
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'N' 40-7F drivers/block/nvme.c
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'O' 00-06 mtd/ubi-user.h UBI
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'P' all linux/soundcard.h conflict!
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'P' 60-6F sound/sscape_ioctl.h conflict!
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'P' 00-0F drivers/usb/class/usblp.c conflict!
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'P' 01-09 drivers/misc/pci_endpoint_test.c conflict!
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'Q' all linux/soundcard.h
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'R' 00-1F linux/random.h conflict!
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'R' 01 linux/rfkill.h conflict!
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'R' C0-DF net/bluetooth/rfcomm.h
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'S' all linux/cdrom.h conflict!
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'S' 80-81 scsi/scsi_ioctl.h conflict!
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'S' 82-FF scsi/scsi.h conflict!
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'S' 00-7F sound/asequencer.h conflict!
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'T' all linux/soundcard.h conflict!
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'T' 00-AF sound/asound.h conflict!
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'T' all arch/x86/include/asm/ioctls.h conflict!
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'T' C0-DF linux/if_tun.h conflict!
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'U' all sound/asound.h conflict!
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'U' 00-CF linux/uinput.h conflict!
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'U' 00-EF linux/usbdevice_fs.h
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'U' C0-CF drivers/bluetooth/hci_uart.h
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'V' all linux/vt.h conflict!
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'V' all linux/videodev2.h conflict!
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'V' C0 linux/ivtvfb.h conflict!
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'V' C0 linux/ivtv.h conflict!
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'V' C0 media/davinci/vpfe_capture.h conflict!
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'V' C0 media/si4713.h conflict!
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'W' 00-1F linux/watchdog.h conflict!
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'W' 00-1F linux/wanrouter.h conflict! (pre 3.9)
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'W' 00-3F sound/asound.h conflict!
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'W' 40-5F drivers/pci/switch/switchtec.c
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'X' all fs/xfs/xfs_fs.h conflict!
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and fs/xfs/linux-2.6/xfs_ioctl32.h
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and include/linux/falloc.h
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and linux/fs.h
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'X' all fs/ocfs2/ocfs_fs.h conflict!
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'X' 01 linux/pktcdvd.h conflict!
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'Y' all linux/cyclades.h
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'Z' 14-15 drivers/message/fusion/mptctl.h
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'[' 00-3F linux/usb/tmc.h USB Test and Measurement Devices
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<mailto:gregkh@linuxfoundation.org>
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'a' all linux/atm*.h, linux/sonet.h ATM on linux
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<http://lrcwww.epfl.ch/>
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'a' 00-0F drivers/crypto/qat/qat_common/adf_cfg_common.h conflict! qat driver
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'b' 00-FF conflict! bit3 vme host bridge
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<mailto:natalia@nikhefk.nikhef.nl>
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'c' all linux/cm4000_cs.h conflict!
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'c' 00-7F linux/comstats.h conflict!
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'c' 00-7F linux/coda.h conflict!
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'c' 00-1F linux/chio.h conflict!
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'c' 80-9F arch/s390/include/asm/chsc.h conflict!
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'c' A0-AF arch/x86/include/asm/msr.h conflict!
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'd' 00-FF linux/char/drm/drm.h conflict!
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'd' 02-40 pcmcia/ds.h conflict!
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'd' F0-FF linux/digi1.h
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'e' all linux/digi1.h conflict!
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'f' 00-1F linux/ext2_fs.h conflict!
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'f' 00-1F linux/ext3_fs.h conflict!
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'f' 00-0F fs/jfs/jfs_dinode.h conflict!
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'f' 00-0F fs/ext4/ext4.h conflict!
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'f' 00-0F linux/fs.h conflict!
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'f' 00-0F fs/ocfs2/ocfs2_fs.h conflict!
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'g' 00-0F linux/usb/gadgetfs.h
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'g' 20-2F linux/usb/g_printer.h
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'h' 00-7F conflict! Charon filesystem
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<mailto:zapman@interlan.net>
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'h' 00-1F linux/hpet.h conflict!
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'h' 80-8F fs/hfsplus/ioctl.c
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'i' 00-3F linux/i2o-dev.h conflict!
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'i' 0B-1F linux/ipmi.h conflict!
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'i' 80-8F linux/i8k.h
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'j' 00-3F linux/joystick.h
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'k' 00-0F linux/spi/spidev.h conflict!
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'k' 00-05 video/kyro.h conflict!
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'k' 10-17 linux/hsi/hsi_char.h HSI character device
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'l' 00-3F linux/tcfs_fs.h transparent cryptographic file system
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<http://web.archive.org/web/*/http://mikonos.dia.unisa.it/tcfs>
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'l' 40-7F linux/udf_fs_i.h in development:
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<http://sourceforge.net/projects/linux-udf/>
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'm' 00-09 linux/mmtimer.h conflict!
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'm' all linux/mtio.h conflict!
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'm' all linux/soundcard.h conflict!
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'm' all linux/synclink.h conflict!
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'm' 00-19 drivers/message/fusion/mptctl.h conflict!
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'm' 00 drivers/scsi/megaraid/megaraid_ioctl.h conflict!
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'n' 00-7F linux/ncp_fs.h and fs/ncpfs/ioctl.c
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'n' 80-8F uapi/linux/nilfs2_api.h NILFS2
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'n' E0-FF linux/matroxfb.h matroxfb
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'o' 00-1F fs/ocfs2/ocfs2_fs.h OCFS2
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'o' 00-03 mtd/ubi-user.h conflict! (OCFS2 and UBI overlaps)
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'o' 40-41 mtd/ubi-user.h UBI
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'o' 01-A1 linux/dvb/*.h DVB
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'p' 00-0F linux/phantom.h conflict! (OpenHaptics needs this)
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'p' 00-1F linux/rtc.h conflict!
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'p' 00-3F linux/mc146818rtc.h conflict!
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'p' 40-7F linux/nvram.h
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'p' 80-9F linux/ppdev.h user-space parport
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<mailto:tim@cyberelk.net>
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'p' A1-A5 linux/pps.h LinuxPPS
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<mailto:giometti@linux.it>
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'q' 00-1F linux/serio.h
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'q' 80-FF linux/telephony.h Internet PhoneJACK, Internet LineJACK
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linux/ixjuser.h <http://web.archive.org/web/*/http://www.quicknet.net>
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'r' 00-1F linux/msdos_fs.h and fs/fat/dir.c
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's' all linux/cdk.h
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't' 00-7F linux/ppp-ioctl.h
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't' 80-8F linux/isdn_ppp.h
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't' 90-91 linux/toshiba.h toshiba and toshiba_acpi SMM
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'u' 00-1F linux/smb_fs.h gone
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'u' 20-3F linux/uvcvideo.h USB video class host driver
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'u' 40-4f linux/udmabuf.h userspace dma-buf misc device
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'v' 00-1F linux/ext2_fs.h conflict!
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'v' 00-1F linux/fs.h conflict!
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'v' 00-0F linux/sonypi.h conflict!
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'v' 00-0F media/v4l2-subdev.h conflict!
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'v' C0-FF linux/meye.h conflict!
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'w' all CERN SCI driver
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'y' 00-1F packet based user level communications
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<mailto:zapman@interlan.net>
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'z' 00-3F CAN bus card conflict!
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<mailto:hdstich@connectu.ulm.circular.de>
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'z' 40-7F CAN bus card conflict!
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<mailto:oe@port.de>
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'z' 10-4F drivers/s390/crypto/zcrypt_api.h conflict!
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'|' 00-7F linux/media.h
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0x80 00-1F linux/fb.h
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0x89 00-06 arch/x86/include/asm/sockios.h
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0x89 0B-DF linux/sockios.h
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0x89 E0-EF linux/sockios.h SIOCPROTOPRIVATE range
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0x89 E0-EF linux/dn.h PROTOPRIVATE range
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0x89 F0-FF linux/sockios.h SIOCDEVPRIVATE range
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0x8B all linux/wireless.h
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0x8C 00-3F WiNRADiO driver
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<http://www.winradio.com.au/>
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0x90 00 drivers/cdrom/sbpcd.h
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0x92 00-0F drivers/usb/mon/mon_bin.c
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0x93 60-7F linux/auto_fs.h
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0x94 all fs/btrfs/ioctl.h Btrfs filesystem
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and linux/fs.h some lifted to vfs/generic
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0x97 00-7F fs/ceph/ioctl.h Ceph file system
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0x99 00-0F 537-Addinboard driver
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<mailto:buk@buks.ipn.de>
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0xA0 all linux/sdp/sdp.h Industrial Device Project
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<mailto:kenji@bitgate.com>
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0xA1 0 linux/vtpm_proxy.h TPM Emulator Proxy Driver
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0xA3 80-8F Port ACL in development:
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<mailto:tlewis@mindspring.com>
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0xA3 90-9F linux/dtlk.h
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0xA4 00-1F uapi/linux/tee.h Generic TEE subsystem
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0xAA 00-3F linux/uapi/linux/userfaultfd.h
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0xAB 00-1F linux/nbd.h
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0xAC 00-1F linux/raw.h
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0xAD 00 Netfilter device in development:
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<mailto:rusty@rustcorp.com.au>
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0xAE all linux/kvm.h Kernel-based Virtual Machine
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<mailto:kvm@vger.kernel.org>
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0xAF 00-1F linux/fsl_hypervisor.h Freescale hypervisor
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0xB0 all RATIO devices in development:
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<mailto:vgo@ratio.de>
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0xB1 00-1F PPPoX <mailto:mostrows@styx.uwaterloo.ca>
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0xB3 00 linux/mmc/ioctl.h
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0xB4 00-0F linux/gpio.h <mailto:linux-gpio@vger.kernel.org>
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|
0xB5 00-0F uapi/linux/rpmsg.h <mailto:linux-remoteproc@vger.kernel.org>
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|
0xB6 all linux/fpga-dfl.h
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|
0xC0 00-0F linux/usb/iowarrior.h
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|
0xCA 00-0F uapi/misc/cxl.h
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|
0xCA 10-2F uapi/misc/ocxl.h
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|
0xCA 80-BF uapi/scsi/cxlflash_ioctl.h
|
|
0xCB 00-1F CBM serial IEC bus in development:
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|
<mailto:michael.klein@puffin.lb.shuttle.de>
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|
0xCC 00-0F drivers/misc/ibmvmc.h pseries VMC driver
|
|
0xCD 01 linux/reiserfs_fs.h
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|
0xCF 02 fs/cifs/ioctl.c
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|
0xDB 00-0F drivers/char/mwave/mwavepub.h
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|
0xDD 00-3F ZFCP device driver see drivers/s390/scsi/
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|
<mailto:aherrman@de.ibm.com>
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|
0xE5 00-3F linux/fuse.h
|
|
0xEC 00-01 drivers/platform/chrome/cros_ec_dev.h ChromeOS EC driver
|
|
0xF3 00-3F drivers/usb/misc/sisusbvga/sisusb.h sisfb (in development)
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|
<mailto:thomas@winischhofer.net>
|
|
0xF4 00-1F video/mbxfb.h mbxfb
|
|
<mailto:raph@8d.com>
|
|
0xF6 all LTTng Linux Trace Toolkit Next Generation
|
|
<mailto:mathieu.desnoyers@efficios.com>
|
|
0xFD all linux/dm-ioctl.h
|