[CRYPTO] Add x86_64 asm AES

Implementation:
===============
The encrypt/decrypt code is based on an x86 implementation I did a while
ago which I never published. This unpublished implementation does
include an assembler based key schedule and precomputed tables. For
simplicity and best acceptance, however, I took Gladman's in-kernel code
for table generation and key schedule for the kernel port of my
assembler code and modified this code to produce the key schedule as
required by my assembler implementation. File locations and Kconfig are
kept similar to the i586 AES assembler implementation.
It may seem a little bit strange to use 32 bit I/O and registers in the
assembler implementation but this gives the best code size. My
implementation takes one instruction more per round compared to
Gladman's x86 assembler but it doesn't require any stack for local
variables or saved registers and it is less serialized than Gladman's
code.
Note that all comparisons to Gladman's code were done after my code was
implemented. I did only use FIPS PUB 197 for the implementation so my
implementation is independent work.
If anybody has a better assembler solution for x86_64 I'll be pleased to
have my code replaced with the better solution.

Testing:
========
The implementation passes the in-kernel crypto testing module and I'm
running it without any problems on my laptop where it is mainly used for
dm-crypt.

Microbenchmark:
===============
The microbenchmark was done in userspace with similar compile flags as
used during kernel compile.
Encrypt/decrypt is about 35% faster than the generic C implementation.
As the generic C as well as my assembler implementation are both table
I don't really expect that there is much room for further
improvements though I'll be glad to be corrected here.
The key schedule is about 5% slower than the generic C implementation.
This is due to the fact that some more work has to be done in the key
schedule routine to fit the schedule to the assembler implementation.

Code Size:
==========
Encrypt and decrypt are together about 2.1 Kbytes smaller than the
generic C implementation which is important with regard to L1 cache
usage. The key schedule routine is about 100 bytes larger than the
generic C implementation.

Data Size:
==========
There's no difference in data size requirements between the assembler
implementation and the generic C implementation.

License:
========
Gladmans's code is dual BSD/GPL whereas my assembler code is GPLv2 only
(I'm  not going to change the license for my code). So I had to change
the module license for the x86_64 aes module from 'Dual BSD/GPL' to
'GPL' to reflect the most restrictive license within the module.

Signed-off-by: Andreas Steinmetz <ast@domdv.de>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 21 insertions, 1 deletions

diff --git a/crypto/Kconfig b/crypto/Kconfig
index 90d6089d60ed..256c0b1fed10 100644
--- a/crypto/Kconfig
+++ b/crypto/Kconfig
@@ -146,7 +146,7 @@ config CRYPTO_SERPENT
 
 config CRYPTO_AES
         tristate "AES cipher algorithms"
-        depends on CRYPTO && !((X86 || UML_X86) && !64BIT)
+        depends on CRYPTO && !(X86 || UML_X86)
         help
           AES cipher algorithms (FIPS-197). AES uses the Rijndael 
           algorithm.
@@ -184,6 +184,26 @@ config CRYPTO_AES_586
 
           See <http://csrc.nist.gov/encryption/aes/> for more information.
 
+config CRYPTO_AES_X86_64
+        tristate "AES cipher algorithms (x86_64)"
+        depends on CRYPTO && ((X86 || UML_X86) && 64BIT)
+        help
+          AES cipher algorithms (FIPS-197). AES uses the Rijndael 
+          algorithm.
+
+          Rijndael appears to be consistently a very good performer in
+          both hardware and software across a wide range of computing 
+          environments regardless of its use in feedback or non-feedback 
+          modes. Its key setup time is excellent, and its key agility is 
+          good. Rijndael's very low memory requirements make it very well 
+          suited for restricted-space environments, in which it also 
+          demonstrates excellent performance. Rijndael's operations are 
+          among the easiest to defend against power and timing attacks. 
+
+          The AES specifies three key sizes: 128, 192 and 256 bits        
+
+          See <http://csrc.nist.gov/encryption/aes/> for more information.
+
 config CRYPTO_CAST5
         tristate "CAST5 (CAST-128) cipher algorithm"
         depends on CRYPTO