583fa5e71c
Add a straightforward IOCTL that provides a mechanism for userspace to query the supported memory device commands. CXL commands as they appear to userspace are described as part of the UAPI kerneldoc. The command list returned via this IOCTL will contain the full set of commands that the driver supports, however, some of those commands may not be available for use by userspace. Memory device commands first appear in the CXL 2.0 specification. They are submitted through a mailbox mechanism specified in the CXL 2.0 specification. The send command allows userspace to issue mailbox commands directly to the hardware. The list of available commands to send are the output of the query command. The driver verifies basic properties of the command and possibly inspect the input (or output) payload to determine whether or not the command is allowed (or might taint the kernel). Reported-by: kernel test robot <lkp@intel.com> # bug in earlier revision Reported-by: Stephen Rothwell <sfr@canb.auug.org.au> Signed-off-by: Ben Widawsky <ben.widawsky@intel.com> Reviewed-by: Dan Williams <dan.j.williams@intel.com> (v2) Cc: Al Viro <viro@zeniv.linux.org.uk> Link: https://lore.kernel.org/r/20210217040958.1354670-5-ben.widawsky@intel.com Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.