565def1542
The CCM code as originally written attempted to use as few NEON registers as possible, to avoid having to eagerly preserve/restore the entire NEON register file at every call to kernel_neon_begin/end. At that time, this API took a number of NEON registers as a parameter, and only preserved that many registers. Today, the NEON register file is restored lazily, and the old API is long gone. This means we can use as many NEON registers as we can make meaningful use of, which means in the AES case that we can keep all round keys in registers rather than reloading each of them for each AES block processed. On Cortex-A53, this results in a speedup of more than 50%. (From 4 cycles per byte to 2.6 cycles per byte) Signed-off-by: Ard Biesheuvel <ardb@kernel.org> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
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.