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 reStructuredText 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.
Sudeep Holla
authored
FFA_MSG_SEND_DIRECT_{REQ,RESP} supported only x3-x7 to pass implementation
defined values as part of the message. This may not be sufficient sometimes
and also it would be good to use all the registers supported by SMCCC v1.2
(x0-x17) for such register based communication.
Also another limitation with the FFA_MSG_SEND_DIRECT_{REQ,RESP} is the
ability to target a specific service within the partition based on it's
UUID.
In order to address both of the above limitation, FF-A v1.2 introduced
FFA_MSG_SEND_DIRECT_{REQ,RESP}2 which has the ability to target the
message to a specific service based on its UUID within a partition as
well as utilise all the available registers(x4-x17 specifically) for
the communication.
This change adds support for FFA_MSG_SEND_DIRECT_REQ2 and
FFA_MSG_SEND_DIRECT_RESP2.
Message-Id: <20240820-ffa_v1-2-v2-5-18c0c5f3c65e@arm.com>
Signed-off-by: 
Sudeep Holla <sudeep.holla@arm.com>