a80f702696
Make the ARM scalar AES implementation closer to constant-time by disabling interrupts and prefetching the tables into L1 cache. This is feasible because due to ARM's "free" rotations, the main tables are only 1024 bytes instead of the usual 4096 used by most AES implementations. On ARM Cortex-A7, the speed loss is only about 5%. The resulting code is still over twice as fast as aes_ti.c. Responsiveness is potentially a concern, but interrupts are only disabled for a single AES block. Note that even after these changes, the implementation still isn't necessarily guaranteed to be constant-time; see https://cr.yp.to/antiforgery/cachetiming-20050414.pdf for a discussion of the many difficulties involved in writing truly constant-time AES software. But it's valuable to make such attacks more difficult. Much of this patch is based on patches suggested by Ard Biesheuvel. Suggested-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Signed-off-by: Eric Biggers <ebiggers@google.com> Reviewed-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> (cherry picked from commit 913a3aa07d16e5b302f408d497a4b829910de247 https://git.kernel.org/pub/scm/linux/kernel/git/herbert/cryptodev-2.6.git master) Bug: 112008522 Test: As series, see Ic61c13b53facfd2173065be715a7ee5f3af8760b Change-Id: I453a7b71c3bb0051106b37cdb71d4511fd4e388a Signed-off-by: Eric Biggers <ebiggers@google.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.
See Documentation/00-INDEX for a list of what is contained in each file.
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.