On Wed, Oct 22, 2014 at 05:31:32PM +0100, Ard Biesheuvel wrote:

On 22 October 2014 18:25, Catalin Marinas [off-list ref] wrote:

quoted

On Wed, Oct 22, 2014 at 08:15:32AM +0100, Ard Biesheuvel wrote:

quoted

This patch implements the AES key schedule generation using ARMv8
Crypto Instructions. It replaces the table based C implementation
in aes_generic.ko, which means we can drop the dependency on that
module.

I don't really understand the AES stuff but there's something else I
noticed: if you build a kernel with the crypto stuff and run it on an
implementation that does not have the crypto extensions, there does not
seem to be any check for not using these algorithms (or falling back to
the generic implementation). Does the kernel end up with undef faults?

No, that is handled by

https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=67bad2fdb754dbef14596c0b5d28b3a12c8dfe84
https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=3be1a5c4f75989cf457f13f38ff0913dff6d4996

and the modules use module_cpu_feature_match(), so they are only
installed if the corresponding hwcap bit is set.

Ah, I remember that now. Does this allow to use the generic C
implementation if the crypto extensions aren't available?

-- 
Catalin