[PATCH] arm64/lib: add optimized implementation of sha_transform

[Ard Biesheuvel]

On 17 March 2014 22:18, Marek Vasut <marex at denx.de> wrote:
> On Friday, March 14, 2014 at 04:02:33 PM, Ard Biesheuvel wrote:
>> This implementation keeps the 64 bytes of workspace in registers rather
>> than on the stack, eliminating most of the loads and stores, and reducing
>> the instruction count by about 25%.
>>
>> Signed-off-by: Ard Biesheuvel <ard.biesheuvel at linaro.org>
>> ---
>> Hello all,
>>
>> No performance numbers I am allowed to share, unfortunately, so if anyone
>> else (with access to actual, representative hardware) would care to have a
>> go, I would be very grateful.
>>
>> This can be done by building the tcrypt.ko module (CONFIG_CRYPTO_TEST=m),
>> and inserting the module using 'mode=303' as a parameter (note that the
>> insmod always fails, but produces its test output to the kernel log). Also
>> note that the sha_transform() function will be part of the kernel proper,
>> so just rebuilding the sha1_generic module is not sufficient.
>>
>> Cheers,
>
> Won't the function sha_transform() collide with the one in lib/sha1.c ? Or will
> the one in lib/sha1.c be overriden somehow ?
>

No, this works pretty well, in fact: arch/*/lib has precedence over
lib/, and objects (declared with lib-y +=)  are only included to
satisfy unresolved dependencies. So the second (generic) sha1.o will
not get linked.

> Otherwise:
>
> Reviewed-by: Marek Vasut <marex at denx.de>
>

Thanks. I did send a v2 which is actually a lot different from the
version you reviewed, so I won't carry over your reviewed-by without
your acknowledgement.

Cheers,
Ard.