cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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gen-errors.rst (2939B)

      1.. SPDX-License-Identifier: GFDL-1.1-no-invariants-or-later
      2
      3.. _gen_errors:
      4
      5*******************
      6Generic Error Codes
      7*******************
      8
      9
     10.. _gen-errors:
     11
     12.. tabularcolumns:: |p{2.5cm}|p{15.0cm}|
     13
     14.. flat-table:: Generic error codes
     15    :header-rows:  0
     16    :stub-columns: 0
     17    :widths: 1 16
     18
     19
     20    -  -  ``EAGAIN`` (aka ``EWOULDBLOCK``)
     21
     22       -  The ioctl can't be handled because the device is in state where it
     23	  can't perform it. This could happen for example in case where
     24	  device is sleeping and ioctl is performed to query statistics. It
     25	  is also returned when the ioctl would need to wait for an event,
     26	  but the device was opened in non-blocking mode.
     27
     28    -  -  ``EBADF``
     29
     30       -  The file descriptor is not a valid.
     31
     32    -  -  ``EBUSY``
     33
     34       -  The ioctl can't be handled because the device is busy. This is
     35	  typically return while device is streaming, and an ioctl tried to
     36	  change something that would affect the stream, or would require
     37	  the usage of a hardware resource that was already allocated. The
     38	  ioctl must not be retried without performing another action to fix
     39	  the problem first (typically: stop the stream before retrying).
     40
     41    -  -  ``EFAULT``
     42
     43       -  There was a failure while copying data from/to userspace, probably
     44	  caused by an invalid pointer reference.
     45
     46    -  -  ``EINVAL``
     47
     48       -  One or more of the ioctl parameters are invalid or out of the
     49	  allowed range. This is a widely used error code. See the
     50	  individual ioctl requests for specific causes.
     51
     52    -  -  ``ENODEV``
     53
     54       -  Device not found or was removed.
     55
     56    -  -  ``ENOMEM``
     57
     58       -  There's not enough memory to handle the desired operation.
     59
     60    -  -  ``ENOTTY``
     61
     62       -  The ioctl is not supported by the driver, actually meaning that
     63	  the required functionality is not available, or the file
     64	  descriptor is not for a media device.
     65
     66    -  -  ``ENOSPC``
     67
     68       -  On USB devices, the stream ioctl's can return this error, meaning
     69	  that this request would overcommit the usb bandwidth reserved for
     70	  periodic transfers (up to 80% of the USB bandwidth).
     71
     72    -  -  ``EPERM``
     73
     74       -  Permission denied. Can be returned if the device needs write
     75	  permission, or some special capabilities is needed (e. g. root)
     76
     77    -  -  ``EIO``
     78
     79       -  I/O error. Typically used when there are problems communicating with
     80          a hardware device. This could indicate broken or flaky hardware.
     81	  It's a 'Something is wrong, I give up!' type of error.
     82
     83    -  - ``ENXIO``
     84
     85       -  No device corresponding to this device special file exists.
     86
     87
     88.. note::
     89
     90  #. This list is not exhaustive; ioctls may return other error codes.
     91     Since errors may have side effects such as a driver reset,
     92     applications should abort on unexpected errors, or otherwise
     93     assume that the device is in a bad state.
     94
     95  #. Request-specific error codes are listed in the individual
     96     requests descriptions.